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Sample records for pao1 preferentially grows

  1. Effects of long-term use of the preferential COX-2 inhibitor meloxicam on growing pigs

    NARCIS (Netherlands)

    Gorissen, B.M.C.; Uilenreef, J.J.; Bergmann, W.; Meijer, E.; van Rietbergen, B.; van der Staay, F.J.; van Weeren, P.R.; Wolschrijn, C.F.

    2017-01-01

    Meloxicam, a preferential COX-2 inhibitor, is a commonly used nSAID in pigs. Besides having potential side effects on the gastrointestinal tract, this type of drug might potentially affect osteogenesis and chondrogenesis, processes relevant to growing pigs. Therefore, the effects of long-term

  2. Effects of long-term use of the preferential COX-2 inhibitor meloxicam on growing pigs

    NARCIS (Netherlands)

    Gorissen, Ben M C|info:eu-repo/dai/nl/372825788; Uilenreef, Joost J|info:eu-repo/dai/nl/30483095X; Bergmann, Willie|info:eu-repo/dai/nl/36275585X; Meijer, Ellen|info:eu-repo/dai/nl/375288015; van Rietbergen, Bert; van der Staay, Franz Josef|info:eu-repo/dai/nl/074262653; Weeren, P René van; Wolschrijn, Claudia F|info:eu-repo/dai/nl/271539496

    2017-01-01

    Meloxicam, a preferential COX-2 inhibitor, is a commonly used NSAID in pigs. Besides having potential side effects on the gastrointestinal tract, this type of drug might potentially affect osteogenesis and chondrogenesis, processes relevant to growing pigs. Therefore, the effects of long-term

  3. Statistical properties and attack tolerance of growing networks with algebraic preferential attachment

    International Nuclear Information System (INIS)

    Liu Zonghua; Lai Yingcheng; Ye Nong

    2002-01-01

    We consider growing networks with algebraic preferential attachment and address two questions: (1) what is the effect of temporal fluctuations in the number of new links acquired by the network? and (2) what is the network tolerance against random failures and intentional attacks? We find that the fluctuations generally have little effect on the network properties, although they lead to a plateau behavior for small degrees in the connectivity distribution. Formulas are derived for the evolution and distribution of the network connectivity, which are tested by numerical simulations. Numerical study of the effect of failures and attacks suggests that networks constructed under algebraic preferential attachment are more robust than scale-free networks

  4. Effects of long-term use of the preferential COX-2 inhibitor meloxicam on growing pigs.

    Science.gov (United States)

    Gorissen, Ben M C; Uilenreef, Joost J; Bergmann, Wilhelmina; Meijer, Ellen; van Rietbergen, Bert; van der Staay, Franz Josef; Weeren, P René van; Wolschrijn, Claudia F

    2017-11-25

    Meloxicam, a preferential COX-2 inhibitor, is a commonly used NSAID in pigs. Besides having potential side effects on the gastrointestinal tract, this type of drug might potentially affect osteogenesis and chondrogenesis, processes relevant to growing pigs. Therefore, the effects of long-term meloxicam treatment on growing pigs were studied. Twelve piglets (n=6 receiving daily meloxicam 0.4 mg/kg orally from 48 until 110 days of age; n=6 receiving only applesauce (vehicle control)) were subjected to visual and objective gait analysis by pressure plate measurements at several time points. Following euthanasia a complete postmortem examination was performed and samples of the talus and distal tibia, including the distal physis, were collected. Trabecular bone microarchitecture was analysed by microCT scanning, bone stiffness by compression testing and growth plate morphology using light microscopy. Animals were not lame and gait patterns did not differ between the groups. Pathological examination revealed no lesions compatible with known side effects of NSAIDs. Trabecular bone microarchitecture and growth plate morphology did not differ between the two groups. The findings of this in vivo study reduce concerns regarding the long-term use of meloxicam in young, growing piglets. © British Veterinary Association (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. Quorum quenching by an N-acyl-homoserine lactone acylase from Pseudomonas aeruginosa PAO1

    NARCIS (Netherlands)

    Sio, CF; Otten, LG; Cool, RH; Diggle, SP; Braun, PG; Daykin, M; Camara, M; Williams, P; Quax, WJ; Bos, R

    The virulence of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 is controlled by an N-acyl-homoserine lactone (AHL)-dependent quorum-sensing system. During functional analysis of putative acylase genes in the P. aeruginosa PAO1 genome, the PA2385 gene was found to encode an acylase

  6. Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress

    DEFF Research Database (Denmark)

    Orlandi, Viviana T; Bolognese, Fabrizio; Chiodaroli, Luca

    2015-01-01

    by exogenous photosensitizers and visible light. To evaluate whether P. aeruginosa pigments can contribute to its relative tolerance to PDT, we analysed the response to this treatment of isogenic transposon mutants of P. aeruginosa PAO1 with altered pigmentation. In general, in the presence of pigments...

  7. Extracts of Cordia gilletii de wild (Boraginaceae) quench the quorum sensing of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Okusa, Philippe N; Rasamiravaka, Tsiry; Vandeputte, Olivier; Stévigny, Caroline; Jaziri, Mondher El; Duez, Pierre

    2014-01-01

    The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties like disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect on the production of Pseudomonas aeruginosa major virulence factors regulated by QS. The effect of C. gilletii extracts on virulence factors of P. aeruginosa PAO1 was studied by the evaluation of the production of pyocyanine, elastase and biofilm; and by the measurement of the expression of QS-related genes. The dichloromethane extract from root barks was found to quench the production of pyocyanin, a QS-dependent virulence factor in P. aeruginosa PAO1. Moreover, this extract specifically inhibits the expression of several QS-regulated genes (i.e. lasB, rhlA, lasI, lasR, rhlI, and rhlR) and reduces biofilm formation by PAO1. This study contributes to explain the efficacy of C. gilletii in the traditional treatment of infectious diseases caused by P. aeruginosa.

  8. Extracts of Cordia gilletii de wild (Boraginaceae) quench the quorum sensing of Pseudomonas aeruginosa PAO1

    Science.gov (United States)

    Okusa, Philippe N.; Rasamiravaka, Tsiry; Vandeputte, Olivier; Stévigny, Caroline; Jaziri, Mondher El; Duez, Pierre

    2014-01-01

    Aim: The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties like disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect on the production of Pseudomonas aeruginosa major virulence factors regulated by QS. Materials and Methods: The effect of C. gilletii extracts on virulence factors of P. aeruginosa PAO1 was studied by the evaluation of the production of pyocyanine, elastase and biofilm; and by the measurement of the expression of QS-related genes. Results: The dichloromethane extract from root barks was found to quench the production of pyocyanin, a QS-dependent virulence factor in P. aeruginosa PAO1. Moreover, this extract specifically inhibits the expression of several QS-regulated genes (i.e. lasB, rhlA, lasI, lasR, rhlI, and rhlR) and reduces biofilm formation by PAO1. Conclusion: This study contributes to explain the efficacy of C. gilletii in the traditional treatment of infectious diseases caused by P. aeruginosa. PMID:26401363

  9. Effect of bacteriocin and exopolysaccharides isolated from probiotic on P. aeruginosa PAO1 biofilm.

    Science.gov (United States)

    Sharma, Vivek; Harjai, Kusum; Shukla, Geeta

    2018-03-01

    Microorganisms develop biofilms on indwelling medical devices and are associated with biofilm-related infections, resulting in substantial morbidity and mortality. Therefore, to prevent and control biofilm-associated infections, the present study was designed to assess the anti-biofilm potential of postbiotics derived from probiotic organisms against most prevalent biofilm-forming Pseudomonas aeruginosa PAO1. Eighty lactic acid bacteria isolated from eight neonatal fecal samples possessed antibacterial activity against P. aeruginosa PAO1. Among these, only four lactic acid bacteria produced both bacteriocin and exopolysaccharides but only one isolate was found to maximally attenuate the P. aeruginosa PAO1 biofilm. More specifically, the phenotypic and probiotic characterization showed that the isolated lactic acid bacteria were gram positive, non-motile, and catalase and oxidase negative; tolerated acidic and alkaline pH; has bile salt concentration; showed 53% hydrophobicity; and was found to be non-hemolytic. Phylogenetically, the organism was found to be probiotic Lactobacillus fermentum with accession no. KT998657. Interestingly, pre-coating of a microtiter plate either with bacteriocin or with exopolysaccharides as well as their combination significantly (p < 0.05) reduced the number of viable cells forming biofilms to 41.7% compared with simultaneous coating of postbiotics that had 72.4% biofilm-forming viable cells as observed by flow cytometry and confocal laser scanning microscopy. Therefore, it can be anticipated that postbiotics as the natural biointerventions can be employed as the prophylactic agents for medical devices used to treat gastrointestinal and urinary tract infections.

  10. Piper betle leaf extract affects the quorum sensing and hence virulence of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Datta, Siraj; Jana, Debanjan; Maity, Tilak Raj; Samanta, Aveek; Banerjee, Rajarshi

    2016-06-01

    Quorum sensing (QS) plays an important role in virulence of Pseudomonas aeruginosa, blocking of QS ability are viewed as viable antimicrobial chemotherapy and which may prove to be a safe anti-virulent drug. Bioactive components from Piper betle have been reported to possess antimicrobial ability. This study envisages on the anti-QS properties of ethanolic extract of P. betle leaf (PbLE) using P. aeruginosa PAO1 as a model organism. A marked reduction in swarming, swimming, and twitching ability of the bacteria is demonstrated in presence of PbLE. The biofilm and pyocyanin production also shows a marked reduction in presence of PbLE, though it does not affect the bacterial growth. Thus, the studies hint on the possible effect of the bioactive components of PbLE on reducing the virulent ability of the bacteria; identification of bioactive compounds should be investigated further.

  11. Pseudomonas aeruginosa PAO1 exopolysaccharides are important for mixed species biofilm community development and stress tolerance

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    Saravanan ePeriasamy

    2015-08-01

    Full Text Available Pseudomonas aeruginosa PAO1 produces three polysaccharides, alginate, Psl and Pel that play distinct roles in attachment and biofilm formation for monospecies biofilms. Considerably less is known about their role in the development of mixed species biofilm communities. This study has investigated the roles of alginate, Psl and Pel during biofilm formation of P. aeruginosa in a defined and experimentally informative mixed species biofilm community, consisting of P. aeruginosa, Pseudomonas protegens and Klebsiella pneumoniae. Loss of the Psl polysaccharide had the biggest impact on the integration of P. aeruginosa in the mixed species biofilms, where the percent composition of the psl mutant was significantly lower (0.06% than its wild-type parent (2.44%. In contrast, loss of the Pel polysaccharide had no impact on mixed species biofilm development. Loss of alginate or its overproduction resulted in P. aeruginosa representing 8.4% and 18.11%, respectively, of the mixed species biofilm. Dual species biofilms of P. aeruginosa and K. pneumoniae were not affected by loss of alginate, Pel or Psl, while the mucoid P. aeruginosa strain achieved a greater biomass than its parent strain. When P. aeruginosa was grown with P. protegens, loss of the Pel or alginate polysaccharides resulted in biofilms that were not significantly different from biofilms formed by the wild-type PAO1. In contrast, overproduction of alginate resulted in biofilms that were comprised of 35-40% of P. aeruginosa, which was significantly higher than the wild-type (5-20%. Loss of the Psl polysaccharide significantly reduced the percentage composition of P. aeruginosa in dual species biofilms with P. protegens (<1%. Loss of the Psl polysaccharide significantly disrupted the communal stress resistance of the three species biofilms. Thus, the polysaccharide composition of an individual species significantly impacts mixed species biofilm development and the emergent properties of such

  12. Feeding behaviour of Caenorhabditis elegans is an indicator of Pseudomonas aeruginosa PAO1 virulence

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    Shawn Lewenza

    2014-08-01

    Full Text Available Caenorhabditis elegans is commonly used as an infection model for pathogenesis studies in Pseudomonas aeruginosa. The standard virulence assays rely on the slow and fast killing or paralysis of nematodes but here we developed a behaviour assay to monitor the preferred bacterial food sources of C. elegans. We monitored the food preferences of nematodes fed the wild type PAO1 and mutants in the type III secretion (T3S system, which is a conserved mechanism to inject secreted effectors into the host cell cytosol. A ΔexsEΔpscD mutant defective for type III secretion served as a preferred food source, while an ΔexsE mutant that overexpresses the T3S effectors was avoided. Both food sources were ingested and observed in the gastrointestinal tract. Using the slow killing assay, we showed that the ΔexsEΔpscD had reduced virulence and thus confirmed that preferred food sources are less virulent than the wild type. Next we developed a high throughput feeding behaviour assay with 48 possible food colonies in order to screen a transposon mutant library and identify potential virulence genes. C. elegans identified and consumed preferred food colonies from a grid of 48 choices. The mutants identified as preferred food sources included known virulence genes, as well as novel genes not identified in previous C. elegans infection studies. Slow killing assays were performed and confirmed that several preferred food sources also showed reduced virulence. We propose that C. elegans feeding behaviour can be used as a sensitive indicator of virulence for P. aeruginosa PAO1.

  13. Effect of nitrofurans and NO generators on biofilm formation by Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370.

    Science.gov (United States)

    Zaitseva, Julia; Granik, Vladimir; Belik, Alexandr; Koksharova, Olga; Khmel, Inessa

    2009-06-01

    Antibacterial drugs in the nitrofuran series, such as nitrofurazone, furazidin, nitrofurantoin and nifuroxazide, as well as the nitric oxide generators sodium nitroprusside and isosorbide mononitrate in concentrations that do not suppress bacterial growth, were shown to increase the capacity of pathogenic bacteria Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370 to form biofilms. At 25-100microg/ml, nitrofurans 2-2.5-fold enhanced biofilm formation of P. aeruginosa PAO1, and NO donors 3-6-fold. For B. cenocepacia 370, the enhancement was 2-5-fold (nitrofurans) and 4.5-fold (sodium nitroprusside), respectively.

  14. Lysophosphatidic acid inhibition of the accumulation of Pseudomonas aeruginosa PAO1 alginate, pyoverdin, elastase and LasA

    DEFF Research Database (Denmark)

    Laux, D.C.; Corson, J.M.; Givskov, Michael Christian

    2002-01-01

    . In the present study, a lysophospholipid, 1-paimitoyl-2-hydroxy-sn-glycero-3-phosphate [also called monopalmitoylphosphatidic acid (MPPA)], which accumulates in inflammatory exudates, was shown to inhibit the extracellular accumulation of P. aeruginosa PAO1 alginate, elastase, LasA protease and the siderophore...

  15. Origin and characteristics of Pseudomonas aeruginosa PAO1 clones surviving after the induction of transposable prophages

    Energy Technology Data Exchange (ETDEWEB)

    Krylov, V.N.; Solov`era, T.I.; Burkal`tseva, M.V. [State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow (Russian Federation)] [and others

    1995-08-01

    Various mutations cancelling the lethal effect of phage lytic development and simultaneous phenotypic modifications were found in rare clones surviving after incubation at 42{degrees}C of Pseudomonas aeruginosa (D3112 cts15), lysogenic for thermoinducible mutant cts15 of the transposable prophage (TP) D3112. All mutations arose prior to thermal induction. Temperature induction of other bacteriophages (nontransposable) did not lead to selection of bacterial morphological mutants. Therefore, it was concluded that mutagenesis occurred upon the partial (reversible) TP derepression accompanied by coupled replication-transposition of TP, the latter being the direct cause of the mutator effect. Isolation of the P. aeruginosa PAO1 mutant R10 (this mutant is resistant to infection with TP at 42{degrees}C) allowed the proper selection and examination of numerous survivors. Comparison of their types derived from lysogens with different prophage location indicated that the number of secondary sites where TP integration is possible without the loss of cell viability is limited. Several transposition events occurred in the history of some survivors (during a repeated or single derepression event). Type D clones, which produce small colonies, are of special interest, because mechanisms underlying the survival of such clones are extremely diverse, and their phenotypes indicate the possibility of stable chromosomal rearrangements in the genome of P. aeruginosa. 16 refs., 2 figs., 2 tabs.

  16. The Antiproliferative Effect of Cyclodipeptides from Pseudomonas aeruginosa PAO1 on HeLa Cells Involves Inhibition of Phosphorylation of Akt and S6k Kinases.

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    Hernández-Padilla, Laura; Vázquez-Rivera, Dolores; Sánchez-Briones, Luis A; Díaz-Pérez, Alma L; Moreno-Rodríguez, José; Moreno-Eutimio, Mario A; Meza-Carmen, Victor; Cruz, Homero Reyes-De la; Campos-García, Jesús

    2017-06-20

    Pseudomonas aeruginosa PAO1, a potential pathogen of plants and animals, produces the cyclodipeptides cyclo(l-Pro-l-Tyr), cyclo(l-Pro-l-Phe), and cyclo(l-Pro-l-Val) (PAO1-CDPs), whose effects have been implicated in inhibition of human tumor cell line proliferation. Our purpose was to investigate in depth in the mechanisms of HeLa cell proliferation inhibition by the PAO1-CDPs. The results indicate that PAO1-CDPs, both purified individually and in mixtures, inhibited HeLa cell proliferation by arresting the cell cycle at the G0-G1 transition. The crude PAO1-CDPs mixture promoted cell death in HeLa cells in a dose-dependent manner, showing efficacy similar to that of isolated PAO1-CDPs (LD 50 of 60-250 µM) and inducing apoptosis with EC 50 between 0.6 and 3.0 µM. Moreover, PAO1-CDPs showed a higher proapoptotic activity (~10³-10⁵ fold) than their synthetic analogs did. Subsequently, the PAO1-CDPs affected mitochondrial membrane potential and induced apoptosis by caspase-9-dependent pathway. The mechanism of inhibition of cells proliferation in HeLa cells involves inhibition of phosphorylation of both Akt-S473 and S6k-T389 protein kinases, showing a cyclic behavior of their expression and phosphorylation in a time and concentration-dependent fashion. Taken together our findings indicate that PI3K-Akt-mTOR-S6k signaling pathway blockage is involved in the antiproliferative effect of the PAO1-CDPs.

  17. The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1

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    Yee Meng Chong

    2018-04-01

    Full Text Available The quorum sensing (QS system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P. aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C. violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants.

  18. Expression, purification, crystallization and preliminary crystallographic analysis of PA3885 (TpbA) from Pseudomonas aeruginosa PAO1

    International Nuclear Information System (INIS)

    Yang, Wen; Li, Kan; Bai, Yuwei; Zhou, Ruimin; Zhou, Weihong; Bartlam, Mark

    2010-01-01

    PA3885 (TpbA), a tyrosine phosphatase, may function as a balancing factor between biofilm formation and motility in the opportunistic pathogen P. aeruginosa. Here, the expression, purification, crystallization and preliminary crystallographic analysis of PA3885 from P. aeruginosa PAO1 are reported. Biofilms are important in cell communication and growth in most bacteria and are also responsible for most human clinical infections and diseases. Quorum-sensing systems have been identified to be crucial for biofilm formation and regulation. PA3885 (TpbA), a tyrosine phosphatase, is reported to convert extracellular quorum-sensing signals into internal gene-cascade reactions that result in reduced biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa. Here, PA3885 from P. aeruginosa PAO1 was expressed, purified and crystallized. Single crystals were studied by X-ray crystallography and native diffraction data were collected to 2.8 Å resolution. These crystals were determined to belong to space group C2. It was not possible to conclusively determine the number of proteins in the asymmetric unit from the preliminary X-ray diffraction data analysis alone and attempts to determine the crystal structure of PA3885 are currently under way

  19. Anti-quorum sensing activity of Psidium guajava L. flavonoids against Chromobacterium violaceum and Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Vasavi, Halkare Suryanarayana; Arun, Ananthapadmanabha Bhagwath; Rekha, Punchapady-Devasya

    2014-05-01

    Psidium guajava L., which has been used traditionally as a medicinal plant, was explored for anti-quorum sensing (QS) activity. The anti-QS activity of the flavonoid (FL) fraction of P. guajava leaves was determined using a biosensor bioassay with Chromobacterium violaceum CV026. Detailed investigation of the effects of the FL-fraction on QS-regulated violacein production in C. violaceum ATCC12472 and pyocyanin production, proteolytic, elastolytic activities, swarming motility and biofilm formation in Pseudomonas aeruginosa PAO1 was performed using standard methods. Possible mechanisms of QS-inhibition were studied by assessing violacein production in response to N-acyl homoserine lactone (AHL) synthesis in the presence of the FL-fraction in C. violaceum ATCC31532 and by evaluating the induction of violacein in the mutant C. violaceum CV026 by AHL extracted from the culture supernatants of C. violaceum 31532. Active compounds in the FL-fraction were identified by liquid chromatography-mass spectrometry (LC-MS). Inhibition of violacein production by the FL-fraction in a C. violaceum CV026 biosensor bioassay indicated possible anti-QS activity. The FL-fraction showed concentration-dependent decreases in violacein production in C. violaceum 12472 and inhibited pyocyanin production, proteolytic and elastolytic activities, swarming motility and biofilm formation in P. aeruginosa PAO1. Interestingly, the FL-fraction did not inhibit AHL synthesis; AHL extracted from cultures of C. violaceum 31532 grown in the presence of the FL-fraction induced violacein in the mutant C. violaceum CV026. LC-MS analysis revealed the presence of quercetin and quercetin-3-O-arabinoside in the FL-fraction. Both quercetin and quercetin-3-O-arabinoside inhibited violacein production in C. violaceum 12472, at 50 and 100 μg/mL, respectively. Results of this study provide scope for further research to exploit these active molecules as anti-QS agents. © 2014 The Societies and Wiley Publishing

  20. Bioproduction of D-Tagatose from D-Galactose Using Phosphoglucose Isomerase from Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Patel, Manisha J; Patel, Arti T; Akhani, Rekha; Dedania, Samir; Patel, Darshan H

    2016-07-01

    Pseudomonas aeruginosa PAO1 phosphoglucose isomerase was purified as an active soluble form by a single-step purification using Ni-NTA chromatography that showed homogeneity on SDS-PAGE with molecular mass ∼62 kDa. The optimum temperature and pH for the maximum isomerization activity with D-galactose were 60 °C and 7.0, respectively. Generally, sugar phosphate isomerases show metal-independent activity but PA-PGI exhibited metal-dependent isomerization activity with aldosugars and optimally catalyzed the D-galactose isomerization in the presence of 1.0 mM MnCl2. The apparent Km and Vmax for D-galactose under standardized conditions were calculated to be 1029 mM (±31.30 with S.E.) and 5.95 U/mg (±0.9 with S.E.), respectively. Equilibrium reached after 180 min with production of 567.51 μM D-tagatose from 1000 mM of D-galactose. Though, the bioconversion ratio is low but it can be increased by immobilization and enzyme engineering. Although various L-arabinose isomerases have been characterized for bioproduction of D-tagatose, P. aeruginosa glucose phosphate isomerase is distinguished from the other L-arabinose isomerases by its optimal temperature (60 °C) for D-tagatose production being mesophilic bacteria, making it an alternate choice for bulk production.

  1. Multiple antibiotic susceptibility of polyphosphate kinase mutants (ppk1 and ppk2 from Pseudomonas aeruginosa PAO1 as revealed by global phenotypic analysis

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    Javiera Ortiz-Severín

    2015-01-01

    Full Text Available BACKGROUND: Pseudomonas aeruginosa is known to be a multidrug resistant opportunistic pathogen. Particularly, P. aeruginosa PAO1 polyphosphate kinase mutant (ppk1 is deficient in motility, quorum sensing, biofilm formation and virulence FINDINGS: By using Phenotypic Microarrays (PM we analyzed near 2000 phenotypes of P. aeruginosa PAO1 polyP kinase mutants (ppk1 and ppk2. We found that both ppk mutants shared most of the phenotypic changes and interestingly many of them related to susceptibility toward numerous and different type of antibiotics such as Ciprofloxacin, Chloramphenicol and Rifampicin CONCLUSIONS: Combining the fact that ppk1 mutants have reduced virulence and are more susceptible to antibiotics, polyP synthesis and particularly PPK1, is a good target for the design of molecules with anti-virulence and anti-persistence properties.

  2. Bioproduction of L-Aspartic Acid and Cinnamic Acid by L-Aspartate Ammonia Lyase from Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Patel, Arti T; Akhani, Rekha C; Patel, Manisha J; Dedania, Samir R; Patel, Darshan H

    2017-06-01

    Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) catalyses the reversible amination and deamination of L-aspartic acid to fumaric acid which can be used to produce important biochemical. In this study, we have explored the characteristics of aspartase from Pseudomonas aeruginosa PAO1 (PA-AspA). To overproduce PA-AspA, the 1425-bp gene was introduced in Escherichia coli BL21 and purified. A 51.0-kDa protein was observed as a homogenous purified protein on SDS-PAGE. The enzyme was optimally active at pH 8.0 and 35 °C. PA-AspA has retained 56% activity after 7 days of incubation at 35 °C, which displays the hyperthermostablility characteristics of the enzyme. PA-AspA is activated in the presence of metal ions and Mg2+ is found to be most effective. Among the substrates tested for specificity of PA-AspA, L-phenylalanine (38.35 ± 2.68) showed the highest specific activity followed by L-aspartic acid (31.21 ± 3.31) and fumarate (5.42 ± 2.94). K m values for L-phenylalanine, L-aspartic acid and fumarate were 1.71 mM, 0.346 μM and 2 M, respectively. The catalytic efficiency (k cat /K m ) for L-aspartic acid (14.18 s -1  mM -1 ) was higher than that for L-phenylalanine (4.65 s -1  mM -1 ). For bioconversion, from an initial concentration of 1000 mM of fumarate and 30 mM of L-phenylalanine, PA-AspA was found to convert 395.31 μM L-aspartic acid and 3.47 mM cinnamic acid, respectively.

  3. Methanol Extract from Anogeissus leiocarpus (DC Guill. et Perr. (Combretaceae Stem Bark Quenches the Quorum Sensing of Pseudomonas aeruginosa PAO1

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    Vincent Ouedraogo

    2016-10-01

    Full Text Available Background: Due to its extensive arsenal of virulence factors and inherent resistance to antibiotics, Pseudomonas aeruginosa is a threat particularly in immunocompromised patients. Considering the central role of quorum sensing in the production of virulence factors, inhibition of bacterial communication mechanism constitute an opportunity to attenuate pathogenicity of bacteria resistant to available antibiotics. Our study aimed to assess the anti-quorum sensing activity of Anogeissus leiocarpus, traditionally used in Burkina Faso, for the treatment of infected burn wounds. Methods: Investigations were carried out on methanol extract from A. leiocarpus stem bark. The reporter strains Chromobacterium violaceum CV026 and P. aeruginosa PAO1 derivatives were used to evidence any interference with the bacterial quorum sensing and expression of related genes. P. aeruginosa PAO1 was used to measure the impact on pyocyanin production. Results: At a sub-inhibitory concentration (100 µg/mL, A. leiocarpus methanol extract quenched the quorum sensing mechanism of P. aeruginosa PAO1 by down-streaming the rhlR gene, with a subsequent reduction of pyocyanin production. Moreover, the antioxidant polyphenols evidenced are able to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-quorum sensing activities of A. leiocarpus stem bark could justify its traditional use in the treatment of infected burn wounds.

  4. Reverting antibiotic tolerance of Pseudomonas aeruginosa PAO1 persister cells by (Z-4-bromo-5-(bromomethylene-3-methylfuran-2(5H-one.

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    Jiachuan Pan

    Full Text Available BACKGROUND: Bacteria are well known to form dormant persister cells that are tolerant to most antibiotics. Such intrinsic tolerance also facilitates the development of multidrug resistance through acquired mechanisms. Thus persister cells are a promising target for developing more effective methods to control chronic infections and help prevent the development of multidrug-resistant bacteria. However, control of persister cells is still an unmet challenge. METHODOLOGY/PRINCIPAL FINDINGS: We show in this report that (Z-4-bromo-5-(bromomethylene-3-methylfuran-2(5H-one (BF8 can restore the antibiotic susceptibility of Pseudomonas aeruginosa PAO1 persister cells at growth non-inhibitory concentrations. Persister control by BF8 was found to be effective against both planktonic and biofilm cells of P. aeruginosa PAO1. Interestingly, although BF8 is an inhibitor of quorum sensing (QS in Gram-negative bacteria, the data in this study suggest that the activities of BF8 to revert antibiotic tolerance of P. aeruginosa PAO1 persister cells is not through QS inhibition and may involve other targets. CONCLUSION: BF8 can sensitize P. aeruginosa persister cells to antibiotics.

  5. [Formation of the Pseudomonas aeruginosa PAO1 biofilms in the presence of hydrogen peroxide; the effect of the AiiA gene].

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    Pliuta, V A; Andreenko, Iu V; Kuznetsov, A E; Khmel', I A

    2013-01-01

    In the natural ecosystems, most bacteria exist as specifically organized biofilms attached to various surfaces; the biofilms have a complex architecture and are surrounded by an exopolymeric matrix. The bacteria in the biofilms are extremely resistant to antibacterial agents. The ability of the pathogenic bacteria to produce biofilms causes serious problems in medicine. Therefore, the study of the action of different compounds with antibacterial activity is of great interest. In this work, we studied the effect of the hydrogen peroxide (H2O2) on the formation of biofilms by Pseudomonas aeruginosa PAO1. It was shown that H2O2 in concentrations that do not suppress bacterial growth (or suppress it only weakly) stimulates the formation of the biofilms. At higher concentrations, H2O2 inhibits the formation of the biofilms. In order to determine if the stimulation of the biofilm formation depends on Quorum Sensing (QS) regulation, the plasmid pME6863 containing the heterologous gene aiiA encoding the N-acyl-homoserine lactonase AiiA was introduced into P. aeruginosa PAO1. The synthesis by cells of this enzyme degrading N-acyl-homoserine lactones (AHL), signaling molecules of the QS systems, led to the absence of the stimulation of the biofilm formation by the action of H2O2. This fact indicates that the stimulation of the biofilm formation in the presence of H2O2 depends on the functioning of the QS systems of the gene expression regulation of P. aeruginosa PAO1.

  6. Ellagic acid derivatives from Terminalia chebula Retz. downregulate the expression of quorum sensing genes to attenuate Pseudomonas aeruginosa PAO1 virulence.

    Directory of Open Access Journals (Sweden)

    Sajal Sarabhai

    Full Text Available BACKGROUND: Burgeoning antibiotic resistance in Pseudomonas aeruginosa has necessitated the development of anti pathogenic agents that can quench acylhomoserine lactone (AHL mediated QS with least risk of resistance. This study explores the anti quorum sensing potential of T. chebula Retz. and identification of probable compounds(s showing anti QS activity and the mechanism of attenuation of P. aeruginosa PAO1 virulence factors. METHODS AND RESULTS: Methanol extract of T. chebula Retz. fruit showed anti QS activity using Agrobacterium tumefaciens A136. Bioactive fraction (F7, obtained by fractionation of methanol extract using Sephadex LH20, showed significant reduction (p<0.001 in QS regulated production of extracellular virulence factors in P. aeruginosa PAO1. Biofilm formation and alginate were significantly (p<0.05 reduced with enhanced (20% susceptibility to tobramycin. Real Time PCR of F7 treated P. aeruginosa showed down regulation of autoinducer synthase (lasI and rhlI and their cognate receptor (lasR and rhlR genes by 89, 90, 90 and 93%, respectively. Electrospray Ionization Mass Spectrometry also showed 90 and 64% reduction in the production of 3-oxo-C(12HSL and C(4HSL after treatment. Decrease in AHLs as one of the mechanisms of quorum quenching by F7 was supported by the reversal of inhibited swarming motility in F7-treated P. aeruginosa PAO1 on addition of C(4HSL. F7 also showed antagonistic activity against 3-oxo-C(12HSL-dependent QS in E. coli bioreporter. C. elegans fed on F7-treated P. aeruginosa showed enhanced survival with LT50 increasing from 24 to 72 h. LC-ESI-MS of F7 revealed the presence of ellagic acid derivatives responsible for anti QS activity in T. chebula extract. CONCLUSIONS: This is the first report on anti QS activity of T. chebula fruit linked to EADs which down regulate the expression of lasIR and rhlIR genes with concomitant decrease in AHLs in P. aeruginosa PAO1 causing attenuation of its virulence factors

  7. Cross-Regulation between the phz1 and phz2 Operons Maintain a Balanced Level of Phenazine Biosynthesis in Pseudomonas aeruginosa PAO1.

    Directory of Open Access Journals (Sweden)

    Qinna Cui

    Full Text Available Gene duplication often provides selective advantages for the survival of microorganisms in adapting to varying environmental conditions. P. aeruginosa PAO1 possesses two seven-gene operons [phz1 (phzA1B1C1D1E1F1G1 and phz2 (phzA2B2C2D2E2F2G2] that are involved in the biosynthesis of phenazine-1-carboxylic acid and its derivatives. Although the two operons are highly homologous and their functions are well known, it is unclear how the two phz operons coordinate their expressions to maintain the phenazine biosynthesis. By constructing single and double deletion mutants of the two phz operons, we found that the phz1-deletion mutant produced the same or less amount of phenazine-1-carboxylic acid and pyocyanin in GA medium than the phz2-knockout mutant while the phz1-phz2 double knockout mutant did not produce any phenazines. By generating phzA1 and phzA2 translational and transcriptional fusions with a truncated lacZ reporter, we found that the expression of the phz1 operon increased significantly at the post-transcriptional level and did not alter at the transcriptional level in the absence of the phz2 operon. Surprisingly, the expression the phz2 operon increased significantly at the post-transcriptional level and only moderately at the transcriptional level in the absence of the phz1 operon. Our findings suggested that a complex cross-regulation existed between the phz1 and phz2 operons. By mediating the upregulation of one phz operon expression while the other was deleted, this crosstalk would maintain the homeostatic balance of phenazine biosynthesis in P. aeruginosa PAO1.

  8. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1

    Directory of Open Access Journals (Sweden)

    Huiming Tang

    2018-03-01

    Full Text Available Quorum sensing (QS regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ, the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT and ΔrhlR strains are significantly higher than those in the ΔlasR strain. Supplementation of ΔlasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa. This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  9. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Tang, Huiming; Zhang, Yunyun; Ma, Yifan; Tang, Mengmeng; Shen, Dongsheng; Wang, Meizhen

    2018-01-01

    Quorum sensing (QS) regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ), the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT) expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT) and Δ rhlR strains are significantly higher than those in the Δ lasR strain. Supplementation of Δ lasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa . This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  10. Normal modal preferential consequence

    CSIR Research Space (South Africa)

    Britz, K

    2012-12-01

    Full Text Available beyond the basic (propositional) KLM postulates, thereby making use of the additional expressivity provided by modal logic. In particular, we show that the additional constraints we impose on the preferential semantics ensure that the rule...

  11. Preferential role restrictions

    CSIR Research Space (South Africa)

    Britz, K

    2013-07-01

    Full Text Available ., Pozzato, G.: ALC+T : a preferential exten- sion of description logics. Fundamenta Informaticae 96(3), 341–372 (2009) 15. Giordano, L., Olivetti, N., Gliozzi, V., Pozzato, G.: A minimal model semantics for nonmonotonic reasoning. In: Proc. JELIA. pp. 228...

  12. Preferential Affirmative Action.

    Science.gov (United States)

    Bell, Derrick A., Jr.

    1982-01-01

    Discusses the philosophical rationale for preferential affirmative action presented by Daniel C. Maguire in "A New American Justice." Maintains that self-interest bars present society's acceptance of Maguire's theories of justice, as demonstrated in negative reactions to the Harvard Law Review's affirmative action plan. (MJL)

  13. Grow, Baby, Grow

    Science.gov (United States)

    Maybe you quit smoking during your pregnancy. Or maybe you struggled and weren’t able to stay quit. Now that your baby is here, trying to stay away from smoking is still important. That’s because the chemicals in smoke can make it harder for your baby to grow like he or she should.

  14. Preferential reasoning for modal logics

    CSIR Research Space (South Africa)

    Britz, K

    2011-11-01

    Full Text Available Modal logic is the foundation for a versatile and well-established class of knowledge representation formalisms in artificial intelligence. Enriching modal logics with non-monotonic reasoning capabilities such as preferential reasoning as developed...

  15. Biosynthesis of the Common Polysaccharide Antigen of Pseudomonas aeruginosa PAO1: Characterization and Role of GDP-D-Rhamnose:GlcNAc/GalNAc-Diphosphate-Lipid α1,3-D-Rhamnosyltransferase WbpZ.

    Science.gov (United States)

    Wang, Shuo; Hao, Youai; Lam, Joseph S; Vlahakis, Jason Z; Szarek, Walter A; Vinnikova, Anna; Veselovsky, Vladimir V; Brockhausen, Inka

    2015-06-15

    The opportunistic pathogen Pseudomonas aeruginosa produces two major cell surface lipopolysaccharides, characterized by distinct O antigens, called common polysaccharide antigen (CPA) and O-specific antigen (OSA). CPA contains a polymer of D-rhamnose (D-Rha) in α1-2 and α1-3 linkages. Three putative glycosyltransferase genes, wbpX, wbpY, and wbpZ, are part of the CPA biosynthesis cluster. To characterize the enzymatic function of the wbpZ gene product, we chemically synthesized the donor substrate GDP-D-Rha and enzymatically synthesized GDP-D-[(3)H]Rha. Using nuclear magnetic resonance (NMR) spectroscopy, we showed that WbpZ transferred one D-Rha residue from GDP-D-Rha in α1-3 linkage to both GlcNAc- and GalNAc-diphosphate-lipid acceptor substrates. WbpZ is also capable of transferring D-mannose (D-Man) to these acceptors. Therefore, WbpZ has a relaxed specificity with respect to both acceptor and donor substrates. The diphosphate group of the acceptor, however, is required for activity. WbpZ does not require divalent metal ion for activity and exhibits an unusually high pH optimum of 9. WbpZ from PAO1 is therefore a GDP-D-Rha:GlcNAc/GalNAc-diphosphate-lipid α1,3-D-rhamnosyltransferase that has significant activity of GDP-D-Man:GlcNAc/GalNAc-diphosphate-lipid α1,3-D-mannosyltransferase. We used site-directed mutagenesis to replace the Asp residues of the two DXD motifs with Ala. Neither of the mutant constructs of wbpZ (D172A or D254A) could be used to rescue CPA biosynthesis in the ΔwbpZ knockout mutant in a complementation assay. This suggested that D172 and D254 are essential for WbpZ function. This work is the first detailed characterization study of a D-Rha-transferase and a critical step in the development of CPA synthesis inhibitors. This is the first characterization of a D-rhamnosyltransferase and shows that it is essential in Pseudomonas aeruginosa for the synthesis of the common polysaccharide antigen. Copyright © 2015, American Society for

  16. Non-preferential Trading Clubs

    DEFF Research Database (Denmark)

    Raimondos-Møller, Pascalis; Woodland, Alan D.

    2006-01-01

    This paper examines the welfare implications of non-discriminatory tariff reforms by a subset of countries, which we term a non-preferential trading club. We show that there exist coordinated tariff reforms, accompanied by appropriate income transfers between the member countries, that unambiguou......This paper examines the welfare implications of non-discriminatory tariff reforms by a subset of countries, which we term a non-preferential trading club. We show that there exist coordinated tariff reforms, accompanied by appropriate income transfers between the member countries...

  17. A Weighted Evolving Network with Community Size Preferential Attachment

    International Nuclear Information System (INIS)

    Zhuo Zhiwei; Shan Erfang

    2010-01-01

    Community structure is an important characteristic in real complex network. It is a network consists of groups of nodes within which links are dense but among which links are sparse. In this paper, the evolving network include node, link and community growth and we apply the community size preferential attachment and strength preferential attachment to a growing weighted network model and utilize weight assigning mechanism from BBV model. The resulting network reflects the intrinsic community structure with generalized power-law distributions of nodes' degrees and strengths.

  18. Information filtering via preferential diffusion

    Science.gov (United States)

    Lü, Linyuan; Liu, Weiping

    2011-06-01

    Recommender systems have shown great potential in addressing the information overload problem, namely helping users in finding interesting and relevant objects within a huge information space. Some physical dynamics, including the heat conduction process and mass or energy diffusion on networks, have recently found applications in personalized recommendation. Most of the previous studies focus overwhelmingly on recommendation accuracy as the only important factor, while overlooking the significance of diversity and novelty that indeed provide the vitality of the system. In this paper, we propose a recommendation algorithm based on the preferential diffusion process on a user-object bipartite network. Numerical analyses on two benchmark data sets, MovieLens and Netflix, indicate that our method outperforms the state-of-the-art methods. Specifically, it can not only provide more accurate recommendations, but also generate more diverse and novel recommendations by accurately recommending unpopular objects.

  19. Popularity versus similarity in growing networks

    Science.gov (United States)

    Krioukov, Dmitri; Papadopoulos, Fragkiskos; Kitsak, Maksim; Serrano, Mariangeles; Boguna, Marian

    2012-02-01

    Preferential attachment is a powerful mechanism explaining the emergence of scaling in growing networks. If new connections are established preferentially to more popular nodes in a network, then the network is scale-free. Here we show that not only popularity but also similarity is a strong force shaping the network structure and dynamics. We develop a framework where new connections, instead of preferring popular nodes, optimize certain trade-offs between popularity and similarity. The framework admits a geometric interpretation, in which preferential attachment emerges from local optimization processes. As opposed to preferential attachment, the optimization framework accurately describes large-scale evolution of technological (Internet), social (web of trust), and biological (E.coli metabolic) networks, predicting the probability of new links in them with a remarkable precision. The developed framework can thus be used for predicting new links in evolving networks, and provides a different perspective on preferential attachment as an emergent phenomenon.

  20. Hamiltonian dynamics of preferential attachment

    International Nuclear Information System (INIS)

    Zuev, Konstantin; Papadopoulos, Fragkiskos; Krioukov, Dmitri

    2016-01-01

    Prediction and control of network dynamics are grand-challenge problems in network science. The lack of understanding of fundamental laws driving the dynamics of networks is among the reasons why many practical problems of great significance remain unsolved for decades. Here we study the dynamics of networks evolving according to preferential attachment (PA), known to approximate well the large-scale growth dynamics of a variety of real networks. We show that this dynamics is Hamiltonian, thus casting the study of complex networks dynamics to the powerful canonical formalism, in which the time evolution of a dynamical system is described by Hamilton’s equations. We derive the explicit form of the Hamiltonian that governs network growth in PA. This Hamiltonian turns out to be nearly identical to graph energy in the configuration model, which shows that the ensemble of random graphs generated by PA is nearly identical to the ensemble of random graphs with scale-free degree distributions. In other words, PA generates nothing but random graphs with power-law degree distribution. The extension of the developed canonical formalism for network analysis to richer geometric network models with non-degenerate groups of symmetries may eventually lead to a system of equations describing network dynamics at small scales. (paper)

  1. 15 CFR 700.14 - Preferential scheduling.

    Science.gov (United States)

    2010-01-01

    ...) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE REGULATIONS DEFENSE PRIORITIES AND ALLOCATIONS SYSTEM Industrial Priorities § 700.14 Preferential scheduling. (a) A...

  2. Concept model semantics for DL preferential reasoning

    CSIR Research Space (South Africa)

    Britz, K

    2011-07-01

    Full Text Available ., Olivetti, N., Gliozzi, V., Pozzato, G.: ALC +T : a preferential exten- sion of description logics. Fund. Informatica 96(3), 341{372 (2009) 7. Kraus, S., Lehmann, D., Magidor, M.: Nonmonotonic reasoning, preferential mod- els and cumulative logics. Arti...

  3. Growing Pains

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Heat expands and cold contracts: it’s a simple thermodynamic rule. But when temperatures swing from 300 K to near-absolute zero, this rule can mean a contraction of more than 80 metres across the LHC’s 27-km-long cryogenic system. Keeping this growth in check are compensators (a.k.a. bellows), which shrink and stretch in response to thermodynamic changes. Leak tests and X-rays now underway in the tunnel have revealed that these “joints” might be suffering from growing pains…   This 25-μm weld crack is thought to be the cause of the helium leaks. Prior to the LS1 warm-up, CERN’s cryogenic experts knew of two points in the machine’s cryogenic distribution system that were leaking helium. Fortunately, these leaks were sufficiently small, confined to known sub-sectors of the cryogenic line and – with help from the vacuum team (TE-VSC) – could easily be compensated for. But as the machine warmed up f...

  4. Semantic foundation for preferential description logics

    CSIR Research Space (South Africa)

    Britz, K

    2011-12-01

    Full Text Available Description logics are a well-established family of knowledge representation formalisms in Artificial Intelligence. Enriching description logics with non-monotonic reasoning capabilities, especially preferential reasoning as developed by Lehmann...

  5. Discovering Preferential Patterns in Sectoral Trade Networks.

    Science.gov (United States)

    Cingolani, Isabella; Piccardi, Carlo; Tajoli, Lucia

    2015-01-01

    We analyze the patterns of import/export bilateral relations, with the aim of assessing the relevance and shape of "preferentiality" in countries' trade decisions. Preferentiality here is defined as the tendency to concentrate trade on one or few partners. With this purpose, we adopt a systemic approach through the use of the tools of complex network analysis. In particular, we apply a pattern detection approach based on community and pseudocommunity analysis, in order to highlight the groups of countries within which most of members' trade occur. The method is applied to two intra-industry trade networks consisting of 221 countries, relative to the low-tech "Textiles and Textile Articles" and the high-tech "Electronics" sectors for the year 2006, to look at the structure of world trade before the start of the international financial crisis. It turns out that the two networks display some similarities and some differences in preferential trade patterns: they both include few significant communities that define narrow sets of countries trading with each other as preferential destinations markets or supply sources, and they are characterized by the presence of similar hierarchical structures, led by the largest economies. But there are also distinctive features due to the characteristics of the industries examined, in which the organization of production and the destination markets are different. Overall, the extent of preferentiality and partner selection at the sector level confirm the relevance of international trade costs still today, inducing countries to seek the highest efficiency in their trade patterns.

  6. A generalized theory of preferential linking

    Science.gov (United States)

    Hu, Haibo; Guo, Jinli; Liu, Xuan; Wang, Xiaofan

    2014-12-01

    There are diverse mechanisms driving the evolution of social networks. A key open question dealing with understanding their evolution is: How do various preferential linking mechanisms produce networks with different features? In this paper we first empirically study preferential linking phenomena in an evolving online social network, find and validate the linear preference. We propose an analyzable model which captures the real growth process of the network and reveals the underlying mechanism dominating its evolution. Furthermore based on preferential linking we propose a generalized model reproducing the evolution of online social networks, and present unified analytical results describing network characteristics for 27 preference scenarios. We study the mathematical structure of degree distributions and find that within the framework of preferential linking analytical degree distributions can only be the combinations of finite kinds of functions which are related to rational, logarithmic and inverse tangent functions, and extremely complex network structure will emerge even for very simple sublinear preferential linking. This work not only provides a verifiable origin for the emergence of various network characteristics in social networks, but bridges the micro individuals' behaviors and the global organization of social networks.

  7. Preferential sampling in veterinary parasitological surveillance

    Directory of Open Access Journals (Sweden)

    Lorenzo Cecconi

    2016-04-01

    Full Text Available In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of farms using several sampling designs. For example, opportunistic surveys or informative sampling designs are very common. Preferential sampling refers to any situation in which the spatial process and the sampling locations are not independent. Most examples of preferential sampling in the spatial statistics literature are in environmental statistics with focus on pollutant monitors, and it has been shown that, if preferential sampling is present and is not accounted for in the statistical modelling and data analysis, statistical inference can be misleading. In this paper, working in the context of veterinary parasitology, we propose and use geostatistical models to predict the continuous and spatially-varying risk of a parasite infection. Specifically, breaking with the common practice in veterinary parasitological surveillance to ignore preferential sampling even though informative or opportunistic samples are very common, we specify a two-stage hierarchical Bayesian model that adjusts for preferential sampling and we apply it to data on Fasciola hepatica infection in sheep farms in Campania region (Southern Italy in the years 2013-2014.

  8. Comparing perceptual and preferential decision making.

    Science.gov (United States)

    Dutilh, Gilles; Rieskamp, Jörg

    2016-06-01

    Perceptual and preferential decision making have been studied largely in isolation. Perceptual decisions are considered to be at a non-deliberative cognitive level and have an outside criterion that defines the quality of decisions. Preferential decisions are considered to be at a higher cognitive level and the quality of decisions depend on the decision maker's subjective goals. Besides these crucial differences, both types of decisions also have in common that uncertain information about the choice situation has to be processed before a decision can be made. The present work aims to acknowledge the commonalities of both types of decision making to lay bare the crucial differences. For this aim we examine perceptual and preferential decisions with a novel choice paradigm that uses the identical stimulus material for both types of decisions. This paradigm allows us to model the decisions and response times of both types of decisions with the same sequential sampling model, the drift diffusion model. The results illustrate that the different incentive structure in both types of tasks changes people's behavior so that they process information more efficiently and respond more cautiously in the perceptual as compared to the preferential task. These findings set out a perspective for further integration of perceptual and preferential decision making in a single ramework.

  9. Preferential attachment in evolutionary earthquake networks

    Science.gov (United States)

    Rezaei, Soghra; Moghaddasi, Hanieh; Darooneh, Amir Hossein

    2018-04-01

    Earthquakes as spatio-temporal complex systems have been recently studied using complex network theory. Seismic networks are dynamical networks due to addition of new seismic events over time leading to establishing new nodes and links to the network. Here we have constructed Iran and Italy seismic networks based on Hybrid Model and testified the preferential attachment hypothesis for the connection of new nodes which states that it is more probable for newly added nodes to join the highly connected nodes comparing to the less connected ones. We showed that the preferential attachment is present in the case of earthquakes network and the attachment rate has a linear relationship with node degree. We have also found the seismic passive points, the most probable points to be influenced by other seismic places, using their preferential attachment values.

  10. Preferential flow occurs in unsaturated conditions

    Science.gov (United States)

    Nimmo, John R.

    2012-01-01

    Because it commonly generates high-speed, high-volume flow with minimal exposure to solid earth materials, preferential flow in the unsaturated zone is a dominant influence in many problems of infiltration, recharge, contaminant transport, and ecohydrology. By definition, preferential flow occurs in a portion of a medium – that is, a preferred part, whether a pathway, pore, or macroscopic subvolume. There are many possible classification schemes, but usual consideration of preferential flow includes macropore or fracture flow, funneled flow determined by macroscale heterogeneities, and fingered flow determined by hydraulic instability rather than intrinsic heterogeneity. That preferential flow is spatially concentrated associates it with other characteristics that are typical, although not defining: it tends to be unusually fast, to transport high fluxes, and to occur with hydraulic disequilibrium within the medium. It also has a tendency to occur in association with large conduits and high water content, although these are less universal than is commonly assumed. Predictive unsaturated-zone flow models in common use employ several different criteria for when and where preferential flow occurs, almost always requiring a nearly saturated medium. A threshold to be exceeded may be specified in terms of the following (i) water content; (ii) matric potential, typically a value high enough to cause capillary filling in a macropore of minimum size; (iii) infiltration capacity or other indication of incipient surface ponding; or (iv) other conditions related to total filling of certain pores. Yet preferential flow does occur without meeting these criteria. My purpose in this commentary is to point out important exceptions and implications of ignoring them. Some of these pertain mainly to macropore flow, others to fingered or funneled flow, and others to combined or undifferentiated flow modes.

  11. Reverse preferential spread in complex networks

    Science.gov (United States)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  12. Defeasible modes of inference: A preferential perspective

    CSIR Research Space (South Africa)

    Britz, K

    2012-06-01

    Full Text Available . Hence UM = f(Mi; wj) j i 2 f1; 2g; j 2 f1; 2; 3; 4gg. We construct a preferential model (Definition 4) in which to check the satisfiability and truth of a few sentences. The purpose is to illustrate the semantics of our notion of defea- sibility... exceptional situations would the pile be on while the cooler is off, e.g. during a serious malfunction (states s7 and s8). In the preferential model P depicted above, one can check that s6 2 Jh^ p p f:hK: at s6 we have a hazardous situ- ation...

  13. The Probabilistic Nature of Preferential Choice

    Science.gov (United States)

    Rieskamp, Jorg

    2008-01-01

    Previous research has developed a variety of theories explaining when and why people's decisions under risk deviate from the standard economic view of expected utility maximization. These theories are limited in their predictive accuracy in that they do not explain the probabilistic nature of preferential choice, that is, why an individual makes…

  14. Preferential flow from pore to landscape scales

    Science.gov (United States)

    Koestel, J. K.; Jarvis, N.; Larsbo, M.

    2017-12-01

    In this presentation, we give a brief personal overview of some recent progress in quantifying preferential flow in the vadose zone, based on our own work and those of other researchers. One key challenge is to bridge the gap between the scales at which preferential flow occurs (i.e. pore to Darcy scales) and the scales of interest for management (i.e. fields, catchments, regions). We present results of recent studies that exemplify the potential of 3-D non-invasive imaging techniques to visualize and quantify flow processes at the pore scale. These studies should lead to a better understanding of how the topology of macropore networks control key state variables like matric potential and thus the strength of preferential flow under variable initial and boundary conditions. Extrapolation of this process knowledge to larger scales will remain difficult, since measurement technologies to quantify macropore networks at these larger scales are lacking. Recent work suggests that the application of key concepts from percolation theory could be useful in this context. Investigation of the larger Darcy-scale heterogeneities that generate preferential flow patterns at the soil profile, hillslope and field scales has been facilitated by hydro-geophysical measurement techniques that produce highly spatially and temporally resolved data. At larger regional and global scales, improved methods of data-mining and analyses of large datasets (machine learning) may help to parameterize models as well as lead to new insights into the relationships between soil susceptibility to preferential flow and site attributes (climate, land uses, soil types).

  15. Popularity versus similarity in growing networks.

    Science.gov (United States)

    Papadopoulos, Fragkiskos; Kitsak, Maksim; Serrano, M Ángeles; Boguñá, Marián; Krioukov, Dmitri

    2012-09-27

    The principle that 'popularity is attractive' underlies preferential attachment, which is a common explanation for the emergence of scaling in growing networks. If new connections are made preferentially to more popular nodes, then the resulting distribution of the number of connections possessed by nodes follows power laws, as observed in many real networks. Preferential attachment has been directly validated for some real networks (including the Internet), and can be a consequence of different underlying processes based on node fitness, ranking, optimization, random walks or duplication. Here we show that popularity is just one dimension of attractiveness; another dimension is similarity. We develop a framework in which new connections optimize certain trade-offs between popularity and similarity, instead of simply preferring popular nodes. The framework has a geometric interpretation in which popularity preference emerges from local optimization. As opposed to preferential attachment, our optimization framework accurately describes the large-scale evolution of technological (the Internet), social (trust relationships between people) and biological (Escherichia coli metabolic) networks, predicting the probability of new links with high precision. The framework that we have developed can thus be used for predicting new links in evolving networks, and provides a different perspective on preferential attachment as an emergent phenomenon.

  16. Complex networks as an emerging property of hierarchical preferential attachment

    Science.gov (United States)

    Hébert-Dufresne, Laurent; Laurence, Edward; Allard, Antoine; Young, Jean-Gabriel; Dubé, Louis J.

    2015-12-01

    Real complex systems are not rigidly structured; no clear rules or blueprints exist for their construction. Yet, amidst their apparent randomness, complex structural properties universally emerge. We propose that an important class of complex systems can be modeled as an organization of many embedded levels (potentially infinite in number), all of them following the same universal growth principle known as preferential attachment. We give examples of such hierarchy in real systems, for instance, in the pyramid of production entities of the film industry. More importantly, we show how real complex networks can be interpreted as a projection of our model, from which their scale independence, their clustering, their hierarchy, their fractality, and their navigability naturally emerge. Our results suggest that complex networks, viewed as growing systems, can be quite simple, and that the apparent complexity of their structure is largely a reflection of their unobserved hierarchical nature.

  17. Preferential acceleration in collisionless supernova shocks

    International Nuclear Information System (INIS)

    Hainebach, K.; Eichler, D.; Schramm, D.

    1979-01-01

    The preferential acceleration and resulting cosmic ray abundance enhancements of heavy elements (relative to protons) are calculated in the collisionless supernova shock acceleration model described by Eichler in earlier work. Rapidly increasing enhancements up to several tens times solar ratios are obtained as a function of atomic weight over charge at the time of acceleration. For material typical of hot phase interstellar medium, good agreement is obtained with the observed abundance enhancements

  18. Preferential Attachment in Online Networks: Measurement and Explanations

    NARCIS (Netherlands)

    Kunegis, J; Blattner, M; Moser, C.

    2013-01-01

    We perform an empirical study of the preferential attachment phenomenon in temporal networks and show that on the Web, networks follow a nonlinear preferential attachment model in which the exponent depends on the type of network considered. The classical preferential attachment model for networks

  19. Growing media [Chapter 5

    Science.gov (United States)

    Douglass F. Jacobs; Thomas D. Landis; Tara Luna

    2009-01-01

    Selecting the proper growing medium is one of the most important considerations in nursery plant production. A growing medium can be defined as a substance through which roots grow and extract water and nutrients. In native plant nurseries, a growing medium can consist of native soil but is more commonly an "artificial soil" composed of materials such as peat...

  20. Preferential treatment and exemption policy impacts energy

    International Nuclear Information System (INIS)

    Doelle, R.R.

    1991-01-01

    This paper reports on the preferential treatment and exemption policy of the Federal Energy Regulatory Commission (FERC) for State and State Agencies which creates an anticompetitive and restraint of trade attitude in California against the development of alternative energy resources by the private sector when such development competes directly with state owned power generation under the State Water and Central Valley Water Projects, particularly in the area of water and power supply. The existing state water policy fails to address the effects of global warming and the adverse potential of the greenhouse effect in California, i.e. rising tides can seriously impact sea water intrusion problems of the San Francisco Bay-Delta Area by not only flooding agricultural lands in the Delta and Central Valley, but impacting the supply of water to large population areas in Southern and Northern California, especially when coupled with drought conditions. The California investigative research results herein reported demonstrates the fallacy of a preferential treatment and exemption policy in a free market economy, especially when such policy creates the potential for excessive state budget burdens upon the public in the face of questionable subsidies to special interest, i.e., allowing the resulting windfall profits to be passed onto major utilities and commingled at the expense of public interest so as to undermine the financial means for development of alternative energy resources. The cited Congressional and State Legislative Laws which provide the ways and means to resolve any energy or water resource problems are only as good as the enforcement and the commitment by the executive branch of government and the lawmakers to up-hold existing laws

  1. Preferential solvation: dividing surface vs excess numbers.

    Science.gov (United States)

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-04-10

    How do osmolytes affect the conformation and configuration of supramolecular assembly, such as ion channel opening and actin polymerization? The key to the answer lies in the excess solvation numbers of water and osmolyte molecules; these numbers are determinable solely from experimental data, as guaranteed by the phase rule, as we show through the exact solution theory of Kirkwood and Buff (KB). The osmotic stress technique (OST), in contrast, purposes to yield alternative hydration numbers through the use of the dividing surface borrowed from the adsorption theory. However, we show (i) OST is equivalent, when it becomes exact, to the crowding effect in which the osmolyte exclusion dominates over hydration; (ii) crowding is not the universal driving force of the osmolyte effect (e.g., actin polymerization); (iii) the dividing surface for solvation is useful only for crowding, unlike in the adsorption theory which necessitates its use due to the phase rule. KB thus clarifies the true meaning and limitations of the older perspectives on preferential solvation (such as solvent binding models, crowding, and OST), and enables excess number determination without any further assumptions.

  2. Modeling online social networks based on preferential linking

    International Nuclear Information System (INIS)

    Hu Hai-Bo; Chen Jun; Guo Jin-Li

    2012-01-01

    We study the phenomena of preferential linking in a large-scale evolving online social network and find that the linear preference holds for preferential creation, preferential acceptance, and preferential attachment. Based on the linear preference, we propose an analyzable model, which illustrates the mechanism of network growth and reproduces the process of network evolution. Our simulations demonstrate that the degree distribution of the network produced by the model is in good agreement with that of the real network. This work provides a possible bridge between the micro-mechanisms of network growth and the macrostructures of online social networks

  3. The response dynamics of preferential choice.

    Science.gov (United States)

    Koop, Gregory J; Johnson, Joseph G

    2013-12-01

    The ubiquity of psychological process models requires an increased degree of sophistication in the methods and metrics that we use to evaluate them. We contribute to this venture by capitalizing on recent work in cognitive science analyzing response dynamics, which shows that the bearing information processing dynamics have on intended action is also revealed in the motor system. This decidedly "embodied" view suggests that researchers are missing out on potential dependent variables with which to evaluate their models-those associated with the motor response that produces a choice. The current work develops a method for collecting and analyzing such data in the domain of decision making. We first validate this method using widely normed stimuli from the International Affective Picture System (Experiment 1), and demonstrate that curvature in response trajectories provides a metric of the competition between choice options. We next extend the method to risky decision making (Experiment 2) and develop predictions for three popular classes of process model. The data provided by response dynamics demonstrate that choices contrary to the maxim of risk seeking in losses and risk aversion in gains may be the product of at least one "online" preference reversal, and can thus begin to discriminate amongst the candidate models. Finally, we incorporate attentional data collected via eye-tracking (Experiment 3) to develop a formal computational model of joint information sampling and preference accumulation. In sum, we validate response dynamics for use in preferential choice tasks and demonstrate the unique conclusions afforded by response dynamics over and above traditional methods. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Distributed network generation based on preferential attachment in ABS

    NARCIS (Netherlands)

    K. Azadbakht (Keyvan); N. Bezirgiannis (Nikolaos); F.S. de Boer (Frank)

    2017-01-01

    textabstractGeneration of social networks using Preferential Attachment (PA) mechanism is proposed in the Barabasi-Albert model. In this mechanism, new nodes are introduced to the network sequentially and they attach to the existing nodes preferentially where the preference can be based on the

  5. Early detection of preferential channeling in reverse electrodialysis

    NARCIS (Netherlands)

    Vermaas, David; Saakes, Michel; Nijmeijer, Dorothea C.

    2014-01-01

    Membrane applications often experience fouling, which prevent uniform flow distribution through the feed water compartments, i.e. preferential channeling may occur. This research shows the effect of preferential channeling on energy generation from mixing salt water and fresh water using reverse

  6. Preferentially Cytotoxic Constituents of Andrographis paniculata and their Preferential Cytotoxicity against Human Pancreatic Cancer Cell Lines.

    Science.gov (United States)

    Lee, Sullim; Morita, Hiroyuki; Tezuka, Yasuhiro

    2015-07-01

    In the course of our search for anticancer agents based on a novel anti-austerity strategy, we found that the 70% EtOH extract of the crude drug Andrographis Herba (aerial parts of Andrographis paniculata), used in Japanese Kampo medicines, killed PANC-1 human pancreatic cancer cells preferentially in nutrient-deprived medium (NDM). Phytochemical investigation of the 70% EtOH extract led to the isolation of 21 known compounds consisting of six labdane-type diterpenes (11, 15, 17-19, 21), six flavones (5, 7, 10, 12, 14, 20), three flavanones (2, 6, 16), two sterols (3, 8), a fatty acid (1), a phthalate (4), a triterpene (9), and a monoterpene (13). Among them, 14-deoxy-11,12-didehydroandrographolide (17) displayed the most potent preferential cytotoxicity against PANC-1 and PSN-1 cells with PC50 values of 10.0 μM and 9.27 μM, respectively. Microscopical observation, double staining with ethidium bromide (EB) and acridine orange (AO), and flow cytometry with propidium iodide/annexin V double staining indicated that 14-deoxy-11,12-didehydroandrographolide (17) triggered apoptosis-like cell death in NDM with an amino acids and/or serum-sensitive mode.

  7. Preferential Market Access, Foreign Aid and Economic Development

    DEFF Research Database (Denmark)

    Afesorgbor, Sylvanus Kwaku; Abreha, Kaleb Girma

    contributed to the economic development of the beneficiary countries. Focusing on the ACP countries over the period 1970-2009, we show that only the EU preferential scheme is effective in promoting exports and that market access plays a significant and economically large role in the development of beneficiary......Several studies highlight that exporters in developing countries face substantial trade costs. To reduce these costs, a few developed countries mainly Canada, the EU, Japan and the USA granted preferential market access to these exporters. We assess whether these preferential accesses have...

  8. Soil properties and preferential solute transport at the field scale

    DEFF Research Database (Denmark)

    Koestel, J K; Minh, Luong Nhat; Nørgaard, Trine

    An important fraction of water flow and solute transport through soil takes place through preferential flow paths. Although this had been already observed in the nineteenth century, it had been forgotten by the scientific community until it was rediscovered during the 1970s. The awareness...... of the relevance of preferential flow was broadly re-established in the community by the early 1990s. However, since then, the notion remains widespread among soil scientists that the occurrence and strength of preferential flow cannot be predicted from measurable proxy variables such as soil properties or land...

  9. Growing Safflower in Utah

    OpenAIRE

    Pace, M. G.; Israelsen, C. E.; Creech, E.; Allen, N.

    2015-01-01

    This fact sheet provides information on growing safflower in Utah. It has become popular on dryland farms in rotation with winter wheat. Safflower seed provides three products, oil, meal, and birdseed.

  10. Conceptualization of preferential flow for hillslope stability assessment

    Science.gov (United States)

    Kukemilks, Karlis; Wagner, Jean-Frank; Saks, Tomas; Brunner, Philip

    2018-03-01

    This study uses two approaches to conceptualize preferential flow with the goal to investigate their influence on hillslope stability. Synthetic three-dimensional hydrogeological models using dual-permeability and discrete-fracture conceptualization were subsequently integrated into slope stability simulations. The slope stability simulations reveal significant differences in slope stability depending on the preferential flow conceptualization applied, despite similar small-scale hydrogeological responses of the system. This can be explained by a local-scale increase of pore-water pressures observed in the scenario with discrete fractures. The study illustrates the critical importance of correctly conceptualizing preferential flow for slope stability simulations. It further demonstrates that the combination of the latest generation of physically based hydrogeological models with slope stability simulations allows for improvement to current modeling approaches through more complex consideration of preferential flow paths.

  11. Emergence of global preferential attachment from local interaction

    International Nuclear Information System (INIS)

    Li Menghui; Fan Ying; Wu Jinshan; Di Zengru; Gao Liang

    2010-01-01

    Global degree/strength-based preferential attachment is widely used as an evolution mechanism of networks. But it is hard to believe that any individual can get global information and shape the network architecture based on it. In this paper, it is found that the global preferential attachment emerges from the local interaction models, including the distance-dependent preferential attachment (DDPA) evolving model of weighted networks (Li et al 2006 New J. Phys. 8 72), the acquaintance network model (Davidsen et al 2002 Phys. Rev. Lett. 88 128701) and the connecting nearest-neighbor (CNN) model (Vazquez 2003 Phys. Rev. E 67 056104). For the DDPA model and the CNN model, the attachment rate depends linearly on the degree or vertex strength, whereas for the acquaintance network model, the dependence follows a sublinear power law. It implies that for the evolution of social networks, local contact could be more fundamental than the presumed global preferential attachment.

  12. Preferential attachment in the evolution of metabolic networks

    Directory of Open Access Journals (Sweden)

    Elofsson Arne

    2005-11-01

    Full Text Available Abstract Background Many biological networks show some characteristics of scale-free networks. Scale-free networks can evolve through preferential attachment where new nodes are preferentially attached to well connected nodes. In networks which have evolved through preferential attachment older nodes should have a higher average connectivity than younger nodes. Here we have investigated preferential attachment in the context of metabolic networks. Results The connectivities of the enzymes in the metabolic network of Escherichia coli were determined and representatives for these enzymes were located in 11 eukaryotes, 17 archaea and 46 bacteria. E. coli enzymes which have representatives in eukaryotes have a higher average connectivity while enzymes which are represented only in the prokaryotes, and especially the enzymes only present in βγ-proteobacteria, have lower connectivities than expected by chance. Interestingly, the enzymes which have been proposed as candidates for horizontal gene transfer have a higher average connectivity than the other enzymes. Furthermore, It was found that new edges are added to the highly connected enzymes at a faster rate than to enzymes with low connectivities which is consistent with preferential attachment. Conclusion Here, we have found indications of preferential attachment in the metabolic network of E. coli. A possible biological explanation for preferential attachment growth of metabolic networks is that novel enzymes created through gene duplication maintain some of the compounds involved in the original reaction, throughout its future evolution. In addition, we found that enzymes which are candidates for horizontal gene transfer have a higher average connectivity than other enzymes. This indicates that while new enzymes are attached preferentially to highly connected enzymes, these highly connected enzymes have sometimes been introduced into the E. coli genome by horizontal gene transfer. We speculate

  13. Evolutionary game dynamics in a growing structured population

    Energy Technology Data Exchange (ETDEWEB)

    Poncela, Julia; Gomez-Gardenes, Jesus; Moreno, Yamir [Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, E-50009 Zaragoza (Spain); Traulsen, Arne [Emmy-Noether Group for Evolutionary Dynamics, Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, 24306 Ploen (Germany)], E-mail: traulsen@evolbio.mpg.de

    2009-08-15

    We discuss a model for evolutionary game dynamics in a growing, network-structured population. In our model, new players can either make connections to random preexisting players or preferentially attach to those that have been successful in the past. The latter depends on the dynamics of strategies in the game, which we implement following the so-called Fermi rule such that the limits of weak and strong strategy selection can be explored. Our framework allows to address general evolutionary games. With only two parameters describing the preferential attachment and the intensity of selection, we describe a wide range of network structures and evolutionary scenarios. Our results show that even for moderate payoff preferential attachment, over represented hubs arise. Interestingly, we find that while the networks are growing, high levels of cooperation are attained, but the same network structure does not promote cooperation as a static network. Therefore, the mechanism of payoff preferential attachment is different to those usually invoked to explain the promotion of cooperation in static, already-grown networks.

  14. Evolutionary game dynamics in a growing structured population

    International Nuclear Information System (INIS)

    Poncela, Julia; Gomez-Gardenes, Jesus; Moreno, Yamir; Traulsen, Arne

    2009-01-01

    We discuss a model for evolutionary game dynamics in a growing, network-structured population. In our model, new players can either make connections to random preexisting players or preferentially attach to those that have been successful in the past. The latter depends on the dynamics of strategies in the game, which we implement following the so-called Fermi rule such that the limits of weak and strong strategy selection can be explored. Our framework allows to address general evolutionary games. With only two parameters describing the preferential attachment and the intensity of selection, we describe a wide range of network structures and evolutionary scenarios. Our results show that even for moderate payoff preferential attachment, over represented hubs arise. Interestingly, we find that while the networks are growing, high levels of cooperation are attained, but the same network structure does not promote cooperation as a static network. Therefore, the mechanism of payoff preferential attachment is different to those usually invoked to explain the promotion of cooperation in static, already-grown networks.

  15. Preferential flow through intact soil cores: Effects of matrix head

    Energy Technology Data Exchange (ETDEWEB)

    Langner, H.W.; Gaber, H.M.; Wraith, J.M.; Huwe, B.; Inskeep, W.P.

    1999-12-01

    Continuous soil pores may act as pathways for preferential flow depending on their size and water status (filled or drained), the latter being largely controlled by the soil matrix head (h). The literature contains a wide range of proposed minimal pore sizes that may contribute to preferential flow. The objective of this study was to examine the relationship between h (and corresponding pore sizes) and preferential solute transport in a naturally structured soil. Tracer ({sup 3}H{sub 2}O and pentafluorobenzoic acid, [PFBA]) miscible displacement experiments were performed at several h values in intact soil cores (15-cm diameter, 30-cm length) using an apparatus especially suited to maintain constant h while collecting large effluent volumes. To test for the occurrence of preferential flow, observed breakthrough curves (BTCs) were evaluated for physical nonequilibrium (PNE) using a comparison between fitted local equilibrium (PNE) and PNE models. Fitting results of the observed BTCs indicated absence of PNE in all solute transport experiments at h {le} {minus}10 cm. Experiments at h {ge} {minus}5 cm consistently exhibited PNE conditions, indicating the presence of preferential flow. These results suggest that soil pores with effective radii of 150 {micro}m and smaller (water-filled at h = {minus}10 cm) do not contribute to preferential flow. Observed pore water velocities were not indicative of the presence or absence of preferential flow conditions. Continuous measurements of soil water content ({theta}) using time domain reflectometry (TDR) revealed that at h = {minus}10 cm, <2% of the soil volume had drained.

  16. Growing Plants and Minds

    Science.gov (United States)

    Presser, Ashley Lewis; Kamdar, Danae; Vidiksis, Regan; Goldstein, Marion; Dominguez, Ximena; Orr, Jillian

    2017-01-01

    Many preschool classrooms explore plant growth. However, because many plants take a long time to grow, it is often hard to facilitate engagement in some practices (i.e., since change is typically not observable from one day to another, children often forget their prior predictions or cannot recall what plants looked like days or weeks earlier).…

  17. Growing Backyard Textiles

    Science.gov (United States)

    Nelson, Eleanor Hall

    1975-01-01

    For those involved in creative work with textiles, the degree of control possible in texture, finish, and color of fiber by growing and processing one's own (perhaps with students' help) can make the experience rewarding. The author describes the processes for flax and nettles and gives tips on necessary equipment. (Author/AJ)

  18. Growing networks with mixed attachment mechanisms

    International Nuclear Information System (INIS)

    Shao Zhigang; Zou Xianwu; Tan Zhijie; Jin Zhunzhi

    2006-01-01

    Networks grow and evolve when new nodes and links are added in. There are two methods to add the links: uniform attachment and preferential attachment. We take account of the addition of links with mixed attachment between uniform attachment and preferential attachment in proportion. By using numerical simulations and analysis based on a continuum theory, we obtain that the degree distribution P(k) has an extended power-law form P(k) ∼ (k + k 0 ) -γ . When the number of edges k of a node is much larger than a certain value k 0 , the degree distribution reduces to the power-law form P(k) ∼ k -γ ; and when k is much smaller than k 0 , the degree distribution degenerates into the exponential form P(k)∼exp(-yk/k 0 ). It has been found that degree distribution possesses this extended power-law form for many real networks, such as the movie actor network, the citation network of scientific papers and diverse protein interaction networks

  19. Properties of acatalasic cells growing in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Krooth, R S; Howell, R R; Hamilton, H B

    1961-07-19

    Acatalasia, a disease due to homozygosity for a Mendelian gene, is characterized by the absence of the enzyme catalase from the tissues of the human body. Red cells from heterozygotes have enzyme activities about one-half normal. In this report, the development of cell lines from skin biopsies of an affected homozygote, a heterozygote and eight control patients is described. The cell type is the euploid fibroblast. It was found that acatalasic cells lacked the enzyme, even after growing for many months in a medium rich in catalase. The control lines all had mean catalase activity double or more that of the heterozygous line. Selection experiments, measuring growth of cells exposed for 20 minutes to varying concentrations of hydrogen peroxide, did not provide a system for preferentially eliminating acatalastic cells. Certain other experiments were performed bearing on the enzymatic defect in this disease. 23 references, 7 figures, 6 tables.

  20. Current challenges in quantifying preferential flow through the vadose zone

    Science.gov (United States)

    Koestel, John; Larsbo, Mats; Jarvis, Nick

    2017-04-01

    In this presentation, we give an overview of current challenges in quantifying preferential flow through the vadose zone. A review of the literature suggests that current generation models do not fully reflect the present state of process understanding and empirical knowledge of preferential flow. We believe that the development of improved models will be stimulated by the increasingly widespread application of novel imaging technologies as well as future advances in computational power and numerical techniques. One of the main challenges in this respect is to bridge the large gap between the scales at which preferential flow occurs (pore to Darcy scales) and the scale of interest for management (fields, catchments, regions). Studies at the pore scale are being supported by the development of 3-D non-invasive imaging and numerical simulation techniques. These studies are leading to a better understanding of how macropore network topology and initial/boundary conditions control key state variables like matric potential and thus the strength of preferential flow. Extrapolation of this knowledge to larger scales would require support from theoretical frameworks such as key concepts from percolation and network theory, since we lack measurement technologies to quantify macropore networks at these large scales. Linked hydro-geophysical measurement techniques that produce highly spatially and temporally resolved data enable investigation of the larger-scale heterogeneities that can generate preferential flow patterns at pedon, hillslope and field scales. At larger regional and global scales, improved methods of data-mining and analyses of large datasets (machine learning) may help in parameterizing models as well as lead to new insights into the relationships between soil susceptibility to preferential flow and site attributes (climate, land uses, soil types).

  1. How to Grow Old

    Institute of Scientific and Technical Information of China (English)

    Bertrand Russell

    2008-01-01

    <正>1. In spite of the title, this article will really be on how not to grow old, which, at my time of life, is a much more important subject. My first advice would be to choose your ancestors carefully. Although both my parents died young, I have done well in this respect as regards my other ancestors. My maternal grandfather, it is true, was cut off in the flower of his youth at the age of sixty-seven,

  2. Preferential ascus discharge during cross maturation in Sordaria brevicollis.

    Science.gov (United States)

    MacDonald, D J; Bond, D J

    1974-02-01

    Crosses involving spore color mutants of Sordaria brevicollis all showed a decline in the frequency of second division asymmetric asci (2:2:2:2's) as the cross matured. This decline was due to the preferential maturation and/or discharge of these asci. The proportion of spindle overlap and recombinational asci within the group did not change as shown by ascus dissection. The preferential discharge was also found to occur in two-point crosses where the asci did not contain wild-type spores.

  3. Preferential interactions and the effect of protein PEGylation

    DEFF Research Database (Denmark)

    Holm, Louise Stenstrup; Thulstrup, Peter Waaben; Kasimova, Marina Robertovna

    2015-01-01

    enthalpy was decreased to half the value for PEGylated lysozyme. The ratio between calorimetric and van't Hoff enthalpy suggests that our PEGylated lysozyme is a dimer. CONCLUSION/SIGNIFICANCE: The PEGylated model protein displayed similar stability responses to the addition of preferentially active...

  4. Unified Model for Generation Complex Networks with Utility Preferential Attachment

    International Nuclear Information System (INIS)

    Wu Jianjun; Gao Ziyou; Sun Huijun

    2006-01-01

    In this paper, based on the utility preferential attachment, we propose a new unified model to generate different network topologies such as scale-free, small-world and random networks. Moreover, a new network structure named super scale network is found, which has monopoly characteristic in our simulation experiments. Finally, the characteristics of this new network are given.

  5. Growth of preferential attachment random graphs via continuous ...

    Indian Academy of Sciences (India)

    Preferential attachment processes have a long history dating back at least to Yule ... We remark that some connections to branching and continuous-time Markov ..... convenience, we provide a short proof of Lemma 2.1 in the general form in ...

  6. The impact of preferential procurement in South African construction ...

    African Journals Online (AJOL)

    The impact of preferential procurement in South African construction industry. ... The outcome of this study shows that there are problems in the implementation of PPPFA during tendering and procurement processes and procedures for achieving success in government projects. Key words: HDIs, PPPFA, Policies, ...

  7. Fitness networks for real world systems via modified preferential attachment

    Science.gov (United States)

    Shang, Ke-ke; Small, Michael; Yan, Wei-sheng

    2017-05-01

    Complex networks are virtually ubiquitous, and the Barabási and Albert model (BA model) has became an acknowledged standard for the modelling of these systems. The so-called BA model is a kind of preferential attachment growth model based on the intuitive premise that popularity is attractive. However, preferential attachment alone is insufficient to describe the diversity of complex networks observed in the real world. In this paper we first use the accuracy of a link prediction method, as a metric for network fitness. The link prediction method predicts the occurrence of links consistent with preferential attachment, the performance of this link prediction scheme is then a natural measure of the ;preferential-attachment-likeness; of a given network. We then propose several modification methods and modified BA models to construct networks which more accurately describe the fitness properties of real networks. We find that all features assortativity, degree distribution and rich-club formation can play significant roles for the network construction and eventual structure. Moreover, link sparsity and the size of a network are key factors for network reconstruction. In addition, we find that the structure of the network which is limited by geographic location (nodes are embedded in a Euclidean space and connectivity is correlated with distances) differs from other typical networks. In social networks, we observe that the high school contact network has similar structure as the friends network and so we speculate that the contact behaviours can reflect real friendships.

  8. Estimating preferential flow in karstic aquifers using statistical mixed models.

    Science.gov (United States)

    Anaya, Angel A; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J; Meeker, John D; Alshawabkeh, Akram N

    2014-01-01

    Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models (SMMs) are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the SMMs used in the study. © 2013, National Ground Water Association.

  9. Predicting Alcohol, Cigarette, and Marijuana Use from Preferential Music Consumption

    Science.gov (United States)

    Oberle, Crystal D.; Garcia, Javier A.

    2015-01-01

    This study investigated whether use of alcohol, cigarettes, and marijuana may be predicted from preferential consumption of particular music genres. Undergraduates (257 women and 78 men) completed a questionnaire assessing these variables. Partial correlation analyses, controlling for sensation-seeking tendencies and behaviors, revealed that…

  10. Growing a market economy

    Energy Technology Data Exchange (ETDEWEB)

    Basu, N.; Pryor, R.J.

    1997-09-01

    This report presents a microsimulation model of a transition economy. Transition is defined as the process of moving from a state-enterprise economy to a market economy. The emphasis is on growing a market economy starting from basic microprinciples. The model described in this report extends and modifies the capabilities of Aspen, a new agent-based model that is being developed at Sandia National Laboratories on a massively parallel Paragon computer. Aspen is significantly different from traditional models of the economy. Aspen`s emphasis on disequilibrium growth paths, its analysis based on evolution and emergent behavior rather than on a mechanistic view of society, and its use of learning algorithms to simulate the behavior of some agents rather than an assumption of perfect rationality make this model well-suited for analyzing economic variables of interest from transition economies. Preliminary results from several runs of the model are included.

  11. The growing fibroadenoma

    International Nuclear Information System (INIS)

    Sanders, Linda M; Sara, Rana

    2015-01-01

    Fibroadenomas (FAs) are the most common tumors of the breast clinically and pathologically in adolescent and young women but may be discovered at any age. With increasing use of core biopsy rather than excision for diagnosis, it is now commonplace to follow these lesions with imaging. To assess the incidence of epithelial abnormalities (atypia, in situ or invasive, ductal or lobular malignancies) in FAs diagnosed by core biopsy and to re-evaluate the management paradigm for any growing FA. A retrospective review of the senior author’s pathology results over 19 years identified 2062 nodular FAs (biopsied by ultrasound or stereotactic guidance). Eighty-three core biopsied FAs were identified which subsequently enlarged. Twelve of 2062 of core biopsied nodules demonstrated atypia, in situ, or invasive malignancy (ductal or lobular) within or adjacent to the FA (0.58%). Eighty-three FAs enlarged and underwent either surgical excision (n = 65), repeat core biopsy (n = 9), or imaging follow-up (n = 9). The incidence of atypia, in situ or invasive malignancy was 0/83 (0%). Two enlarging FAs were subsequently surgically diagnosed as benign phyllodes tumors (PT). Malignancy in or adjacent to a core biopsied FA is rare. The risk of cancer in a growing FA is even rarer; none were present in our series. FAs with abnormal epithelial abnormalities require excision. Otherwise, FAs without epithelial abnormality diagnosed by core biopsy need no specific follow-up considering the negligible incidence of conversion to malignancy. The breast interventionalist must know how to manage discordant pathology results

  12. Is there reciprocity in preferential trade agreements on services?

    OpenAIRE

    Marchetti, Juan; Roy, Martin; Zoratto, Laura

    2012-01-01

    Are market access commitments on services in Preferential Trade Agreements (PTAs) reciprocal or simply unilateral? If reciprocal, do concessions granted in services depend on concessions received from the trading partner in other services or in non-services areas as well? In this paper we investigate the presence of reciprocity in bilateral services agreements, by sub-sector, mode of supply and type of agreement (North-North, South-North, South-South). To do so, we use a database of concessio...

  13. Preferential growth in FeCoV/Ti:N multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, D.; Senthil Kumar, M.; Boeni, P.; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The preferential growth in Fe{sub 0.50}Co{sub 0.48}V{sub 0.02}/Ti:N multilayers was studied by X-ray diffraction. X-ray specular reflectometry and subsequent simulation of the spectra was used to extract information about the thickness and interface roughness of individual layers. The investigation gives structural information about the material combination and its potential for the use of neutron polarizers. (author) 2 figs., 1 tab., 2 refs.

  14. Bioclogging in Porous Media: Preferential Flow Paths and Anomalous Transport

    Science.gov (United States)

    Holzner, M.; Carrel, M.; Morales, V.; Derlon, N.; Beltran, M. A.; Morgenroth, E.; Kaufmann, R.

    2016-12-01

    Biofilms are sessile communities of microorganisms held together by an extracellular polymeric substance that enables surface colonization. In porous media (e.g. soils, trickling filters etc.) biofilm growth has been shown to affect the hydrodynamics in a complex fashion at the pore-scale by clogging individual pores and enhancing preferential flow pathways and anomalous transport. These phenomena are a direct consequence of microbial growth and metabolism, mass transfer processes and complex flow velocity fields possibly exhibiting pronounced three-dimensional features. Despite considerable past work, however, it is not fully understood how bioclogging interacts with flow and mass transport processes in porous media. In this work we use imaging techniques to determine the flow velocities and the distribution of biofilm in a porous medium. Three-dimensional millimodels are packed with a transparent porous medium and a glucose solution to match the optical refractive index. The models are inoculated with planktonic wildtype bacteria and biofilm cultivated for 60 h under a constant flow and nutrient conditions. The pore flow velocities in the increasingly bioclogged medium are measured using 3D particle tracking velocimetry (3D-PTV). The three-dimensional spatial distribution of the biofilm within the pore space is assessed by imaging the model with X-Ray microtomography. We find that biofilm growth increases the complexity of the pore space, leading to the formation of preferential flow pathways and "dead" pore zones. The probability of persistent high and low velocity regions (within preferential paths resp. stagnant flow regions) thus increases upon biofilm growth, leading to an enhancement of anomalous transport. The structural data seems to indicate that the largest pores are not getting clogged and carry the preferential flow, whereas intricated structures develop in the smallest pores, where the flow becomes almost stagnant. These findings may be relevant for

  15. Melting ice, growing trade?

    Directory of Open Access Journals (Sweden)

    Sami Bensassi

    2016-05-01

    Full Text Available Abstract Large reductions in Arctic sea ice, most notably in summer, coupled with growing interest in Arctic shipping and resource exploitation have renewed interest in the economic potential of the Northern Sea Route (NSR. Two key constraints on the future viability of the NSR pertain to bathymetry and the future evolution of the sea ice cover. Climate model projections of future sea ice conditions throughout the rest of the century suggest that even under the most “aggressive” emission scenario, increases in international trade between Europe and Asia will be very low. The large inter-annual variability of weather and sea ice conditions in the route, the Russian toll imposed for transiting the NSR, together with high insurance costs and scarce loading/unloading opportunities, limit the use of the NSR. We show that even if these obstacles are removed, the duration of the opening of the NSR over the course of the century is not long enough to offer a consequent boost to international trade at the macroeconomic level.

  16. Preferential adsorption of uranium ions in aqueous solutions by polymers

    International Nuclear Information System (INIS)

    Sakuragi, Masako; Ichimura, Kunihiro; Fujishige, Shoei; Kato, Masao

    1981-01-01

    Amidoxime fiber and triazine fiber were prepared by chemical modification of commercially available polyacrylonitril fiber. It was found that the Amidoxime fiber is efficient to adsorb uranium ions in the artificial sea water. The efficiency of the preferential adsorption decreases by treatment the material with an acid-or an alkaline-solution. The triazine fiber adsorbs uranium ions only in aqueous solutions of such uranyl acetate, in the absence of other ions. In the artificial sea water, it adsorbs other ions instead of uranium. The preferential adsorption of uranium ions was further investigated with a series of polystyrenesulfonamides. Among the polystyrene derivatives, those having carboxyl groups, derived from imino diacetic acid (PSt-Imi), β-alanine (PSt-Ala), glycine (PSt-Gly), and sarcosine (PSt-Sar) were qualified for further discussion. However, it was found that the amount of adsorption of uranium ions by PSt-Imi decreases with increasing the volume of the artificial sea water and/or the duration of the treatment. Taking into account the facts, the preferential adsorption of uranium ions by PSt-Imi in aqueous solution was discussed in detail. (author)

  17. Formal requirements for exclusion of the preferential right to shares

    Directory of Open Access Journals (Sweden)

    Marjanski Vladimir

    2014-01-01

    Full Text Available A preferential subscription right to shares is a subjective property right of a shareholder based on which he or she has a preferential right of subscription to shares from a new issue in proportion to the number of fully paid-in shares of that class he or she holds on the date of adoption of the decision on issuing of shares compared with the total number of shares of that class. However, this right of a shareholder can be completely or partially excluded, if formal and substantial requirements for such exclusion are met. This paper focuses primarily on analysis of formal requirements for exclusion envisaged by the Serbian Law on Companies with a brief review of EU law and comparative law. According to the Serbian Law on Companies, there are three formal requirements for exclusion of a preferential subscription right: 1. shares are issued through the offer for which there is no obligation to publish a prospectus; 2. there is a written proposal for exclusion from the Board of Directors, or of the Supervisory Board if a company has a two-tier management system; 3. the exclusion is based on a decision of the General Meeting of the Joint-stock company. With regards formal requirements, the paper concentrates on several weaknesses of the Serbian Law on Companies which considerably undermine the position of the so-called small shareholders.

  18. Growing Galaxies Gently

    Science.gov (United States)

    2010-10-01

    New observations from ESO's Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. In the first few billion years after the Big Bang the mass of a typical galaxy increased dramatically and understanding why this happened is one of the hottest problems in modern astrophysics. The results appear in the 14 October issue of the journal Nature. The first galaxies formed well before the Universe was one billion years old and were much smaller than the giant systems - including the Milky Way - that we see today. So somehow the average galaxy size has increased as the Universe has evolved. Galaxies often collide and then merge to form larger systems and this process is certainly an important growth mechanism. However, an additional, gentler way has been proposed. A European team of astronomers has used ESO's Very Large Telescope to test this very different idea - that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early Universe and forming new stars from this primitive material. Just as a commercial company can expand either by merging with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways - by merging with other galaxies or by accreting material. The team leader, Giovanni Cresci (Osservatorio Astrofisico di Arcetri) says: "The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe." The discovery will have a major impact on our understanding of the evolution of the Universe from the Big Bang to the present day. Theories of galaxy formation and evolution may have to be re-written. The group began by selecting three very distant galaxies to see if they could find evidence

  19. Preferential and Non-Preferential Approaches to Trade Liberalization in East Asia: What Differences Do Utilization Rates and Reciprocity Make?

    OpenAIRE

    Menon, Jayant

    2013-01-01

    Previous studies on the impacts of free trade agreements (FTAs) in East Asia have assumed full utilization of preferences. The evidence suggests that this assumption is seriously in error, with the estimated uptake particularly low in East Asia. In this paper, we assume a more realistic utilization rate in estimating impacts. We find that actual utilization rates significantly diminish the benefits from preferential liberalization, but in a non-linear way. Reciprocity is an important motivati...

  20. Statistics of leaders and lead changes in growing networks

    International Nuclear Information System (INIS)

    Godrèche, C; Grandclaude, H; Luck, J M

    2010-01-01

    We investigate various aspects of the statistics of leaders in growing network models defined by stochastic attachment rules. The leader is the node with highest degree at a given time (or the node which reached that degree first if there are co-leaders). This comprehensive study includes the full distribution of the degree of the leader, its identity, the number of co-leaders, as well as several observables characterizing the whole history of lead changes: number of lead changes, number of distinct leaders, lead persistence probability. We successively consider the following network models: uniform attachment, linear attachment (the Barabási–Albert model), and generalized preferential attachment with initial attractiveness

  1. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.; Li, Yan; Cathles, L. M.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  2. Using DC electrical resistivity tomography to quantify preferential flow in fractured rock environments

    CSIR Research Space (South Africa)

    May, F

    2011-09-01

    Full Text Available . This investigation aims to identify preferential flow paths in fractured rock environments. Time-lapse Electrical Resistivity Tomography (TLERT, Lund Imaging System), is regarded as a suitable method for identifying preferential water flow....

  3. Field investigation of preferential fissure flow paths with hydrochemical analysis of small-scale sprinkling experiments

    NARCIS (Netherlands)

    Krzeminska, D.M.; Bogaard, T.A.; Debieche, T.H.; Cervi, F.; Marc, V.; Malet, J.P.

    2014-01-01

    The unsaturated zone largely controls groundwater recharge by buffering precipitation while at the same time providing preferential flow paths for infiltration. The importance of preferential flow on landslide hydrology is recognised in the literature; however, its monitoring and quantification

  4. Numerical modeling of the effect of preferential flow on hillslope hydrology and slope stability

    NARCIS (Netherlands)

    Shao, W.

    2017-01-01

    The topic of this thesis is the quantification of the influence of preferential flow on landslide-triggering in potentially unstable slopes. Preferential flow paths (e.g., cracks, macropores, fissures, pipes, etc.) commonly exists in slopes. Flow velocities in preferential flow paths can be

  5. Innovation and nested preferential growth in chess playing behavior

    Science.gov (United States)

    Perotti, J. I.; Jo, H.-H.; Schaigorodsky, A. L.; Billoni, O. V.

    2013-11-01

    Complexity develops via the incorporation of innovative properties. Chess is one of the most complex strategy games, where expert contenders exercise decision making by imitating old games or introducing innovations. In this work, we study innovation in chess by analyzing how different move sequences are played at the population level. It is found that the probability of exploring a new or innovative move decreases as a power law with the frequency of the preceding move sequence. Chess players also exploit already known move sequences according to their frequencies, following a preferential growth mechanism. Furthermore, innovation in chess exhibits Heaps' law suggesting similarities with the process of vocabulary growth. We propose a robust generative mechanism based on nested Yule-Simon preferential growth processes that reproduces the empirical observations. These results, supporting the self-similar nature of innovations in chess are important in the context of decision making in a competitive scenario, and extend the scope of relevant findings recently discovered regarding the emergence of Zipf's law in chess.

  6. Preferential lentiviral targeting of astrocytes in the central nervous system.

    Directory of Open Access Journals (Sweden)

    Michael Fassler

    Full Text Available The ability to visualize and genetically manipulate specific cell populations of the central nervous system (CNS is fundamental to a better understanding of brain functions at the cellular and molecular levels. Tools to selectively target cells of the CNS include molecular genetics, imaging, and use of transgenic animals. However, these approaches are technically challenging, time consuming, and difficult to control. Viral-mediated targeting of cells in the CNS can be highly beneficial for studying and treating neurodegenerative diseases. Yet, despite specific marking of numerous cell types in the CNS, in vivo selective targeting of astrocytes has not been optimized. In this study, preferential targeting of astrocytes in the CNS was demonstrated using engineered lentiviruses that were pseudotyped with a modified Sindbis envelope and displayed anti-GLAST IgG on their surfaces as an attachment moiety. Viral tropism for astrocytes was initially verified in vitro in primary mixed glia cultures. When injected into the brains of mice, lentiviruses that displayed GLAST IgG on their surface, exhibited preferential astrocyte targeting, compared to pseudotyped lentiviruses that did not incorporate any IgG or that expressed a control isotype IgG. Overall, this approach is highly flexible and can be exploited to selectively target astrocytes or other cell types of the CNS. As such, it can open a window to visualize and genetically manipulate astrocytes or other cells of the CNS as means of research and treatment.

  7. Stationary and nonstationary properties of evolving networks with preferential linkage

    International Nuclear Information System (INIS)

    Jezewski, W.

    2002-01-01

    Networks evolving by preferential attachment of both external and internal links are investigated. The rate of adding an external link is assumed to depend linearly on the degree of a preexisting node to which a new node is connected. The process of creating an internal link, between a pair of existing vertices, is assumed to be controlled entirely by the vertex that has more links than the other vertex in the pair, and the rate of creation of such a link is assumed to be, in general, nonlinear in the degree of the more strongly connected vertex. It is shown that degree distributions of networks evolving only by creating internal links display for large degrees a nonstationary power-law decay with a time-dependent scaling exponent. Nonstationary power-law behaviors are numerically shown to persist even when the number of nodes is not fixed and both external and internal connections are introduced, provided that the rate of preferential attachment of internal connections is nonlinear. It is argued that nonstationary effects are not unlikely in real networks, although these effects may not be apparent, especially in networks with a slowly varying mean degree

  8. Waste streams that preferentially corrode 55-gallon steel storage drums

    International Nuclear Information System (INIS)

    Zirker, L.R.; Beitel, G.A.; Reece, C.M.

    1995-06-01

    When 55-gal steel drum waste containers fail in service, i.e., leak, corrode or breach, the standard fix has been to overpack the drum. When a drum fails and is overpacked into an 83-gal overpack drum, there are several negative consequences. Identifying waste streams that preferentially corrode steel drums is essential to the pollution prevention philosophy that ''an ounce of prevention is worth a pound of cure.'' It is essential that facilities perform pollution prevention measures at the front end of processes to reduce pollution on the back end. If these waste streams can be identified before they are packaged, the initial drum packaging system could be fortified or increased to eliminate future drum failures, breaches, clean-ups, and the plethora of other consequences. Therefore, a survey was conducted throughout the US Department of Energy complex for information concerning waste streams that have demonstrated preferential corrosion of 55-gal steel drums. From 21 site contacts, 21 waste streams were so identified. The major components of these waste streams include acids, salts, and solvent liquids, sludges, and still bottoms. The solvent-based waste streams typically had the shortest time to failure, 0.5 to 2 years. This report provides the results of this survey and research

  9. Antimicrobial and anti-biofilm effect of a novel BODIPY photosensitizer against Pseudomonas aeruginosa PAO1

    DEFF Research Database (Denmark)

    Orlandi, Viviana Teresa; Rybtke, Morten; Caruso, Enrico

    2014-01-01

    Photodynamic therapy (PDT) combines the use of organic dyes (photosensitizers, PSs) and visible light in order to elicit a photo-oxidative stress which causes bacterial death. GD11, a recently synthesized PS belonging to the boron-dipyrromethene (BODIPY) class, was demonstrated to be efficient...

  10. Preparation and characterization of magnetorheological fluids by dispersion of carbonyl iron microparticles in PAO/1-octanol

    International Nuclear Information System (INIS)

    Morillas, Jose R; De Vicente, Juan; Bombard, Antonio J F

    2016-01-01

    This work reports an investigation into the effect of 1-octanol concentration in the formulation of concentrated polyalphaolefin-based magnetorheological fluids. Special emphasis is paid to the understanding of their kinetic stability and redispersibility characteristics in the ‘off-state’ (absence of magnetic field). Techniques employed involve light scattering, electroacoustics and rheometry, using a vane tool, to precisely determine the yield value. The results obtained show a minimum in the rheological material functions for 1-octanol concentrations within the range 0.5–5.0 wt%. This finding is tentatively explained in terms of the potential energy of interaction between the dispersed particles as a result of the formation of 1-octanol micelles in good agreement with Bombard and Dukhin (2014 Langmuir 30 4517–21). (paper)

  11. Preparation and characterization of magnetorheological fluids by dispersion of carbonyl iron microparticles in PAO/1-octanol

    Science.gov (United States)

    Morillas, Jose R.; Bombard, Antonio J. F.; de Vicente, Juan

    2016-01-01

    This work reports an investigation into the effect of 1-octanol concentration in the formulation of concentrated polyalphaolefin-based magnetorheological fluids. Special emphasis is paid to the understanding of their kinetic stability and redispersibility characteristics in the ‘off-state’ (absence of magnetic field). Techniques employed involve light scattering, electroacoustics and rheometry, using a vane tool, to precisely determine the yield value. The results obtained show a minimum in the rheological material functions for 1-octanol concentrations within the range 0.5-5.0 wt%. This finding is tentatively explained in terms of the potential energy of interaction between the dispersed particles as a result of the formation of 1-octanol micelles in good agreement with Bombard and Dukhin (2014 Langmuir 30 4517-21).

  12. Proteomic Response of Pseudomonas aeruginosa PAO1 Adhering to Solid Surfaces

    Directory of Open Access Journals (Sweden)

    Morgan Guilbaud

    2017-08-01

    Full Text Available Pseudomonas aeruginosa is a pathogenic micro-organism responsible for many hospital-acquired infections. It is able to adhere to solid surfaces and develop an immobilized community or so-called biofilm. Many studies have been focusing on the use of specific materials to prevent the formation of these biofilms, but the reactivity of the bacteria in contact to surfaces remains unknown. The aim of this study was to evaluate the impact of the abiotic surface on the physiology of adherent bacteria. Three different materials, stainless steel (SS, glass (G, and polystyrene (PS that were relevant to industrial or medical environments were characterized at the physicochemical level in terms of their hydrophobicity and roughness. We showed that SS was moderately hydrophilic and rough, potentially containing crevices, G was hydrophilic and smooth while PS was hydrophobic and smooth. We further showed that P. aeruginosa cells were more likely able to adhere to SS and G rather than PS surfaces under our experimental conditions. The physiological response of P. aeruginosa when adhering to each of these materials was then evaluated by global proteomic analysis. The abundance of 70 proteins was shown to differ between the materials suggesting that their abundance was modified as a function of the material to which bacteria adhered. Our data lead to enabling the identification of abundance patterns that appeared to be specific to a given surface. Taken together, our data showed that P. aeruginosa is capable of sensing and responding to a surface probably via specific programmes to adapt its physiological response accordingly.

  13. Response of Pseudomonas aeruginosa PAO1 to low shear modeled microgravity

    Data.gov (United States)

    National Aeronautics and Space Administration — Anticipating the risk for infectious disease during space exploration and habitation is a critical factor to ensure safety health and performance of the crewmembers....

  14. Preferential Pathway for Glycine Formation in Star-Forming Regions

    Science.gov (United States)

    Pilling, S.; Boechat-Roberty, H. M.; Baptista, L.; Santos A. C., F.

    Interstellar clouds, similar to that from which the solar system was formed, contain many organic molecules including aldehydes, acids, ketones, and sugars Ehrenfreund & Charnley (2000). Those organic compounds have important functions in terrestrial biochemistry and could also have been important in prebiotic synthesis. The simplest amino acid, glycine (NH2CH2COOH), was recently detected in the hot molecular cores Sgr B2(N-LMH), Orion KL, and W51 e1/e2 Kuan et al. (2003). The formic acid (HCOOH) and acetic acid(CH3COOH) have also been detected in those regions Liu et al. (2002), Remijan et al. (2004). The goal of this work is to study experimentally photoionization and photodissociation processes of glycine precursor molecules, acetic acid and formic acid to elucidate a possible preferentially in the glycine synthesis between ice and gas phase. The measurements were taken at the Brazilian Synchrotron Light Laboratory (LNLS), employing soft X-ray photons from a toroidal grating monochromator TGM) beamline (100 - 310 eV). The experimental set up consists of a high vacuum chamber with a Time-Of-Flight Mass Spectrometer (TOF-MS). Mass spectra were obtained using PhotoElectron PhotoIon Coincidence (PEPICO) technique. Kinetic energy distributions and abundances for each ionic fragment have been obtained from the analysis of the corresponding peak shapes in the mass spectra. Dissociative and non-dissociative photoionization cross sections for both molecules were also determined Boechat-Roberty, Pilling & Santos (2005). Due to the high photodissociation cross section of formic acid it is possible that in PDRs regions, just after molecules evaporation from the grains surface, it is almost destructed by soft X-rays, justifying the observed low abundance of HCOOH in gaseous phase Ehrenfreund et al. (2001). Acetic acid have shown to be more stable to the ionizing field, and its main outcomes from dissociation process were the reactive ionic fragments COOH+ and CH3CO+. To

  15. Growing container seedlings: Three considerations

    Science.gov (United States)

    Kas Dumroese; Thomas D. Landis

    2015-01-01

    The science of growing reforestation and conservation plants in containers has continually evolved, and three simple observations may greatly improve seedling quality. First, retaining stock in its original container for more than one growing season should be avoided. Second, strongly taprooted species now being grown as bareroot stock may be good candidates...

  16. Affecting factors of preferential flow in the forest of the Three Gorges area, Yangtze River

    Institute of Scientific and Technical Information of China (English)

    CHENG Jinhua; ZHANG Hongjiang; HE Fan; QI Shenglin; SUN Yanhong; ZHANG Youyan; SHI Yuhu

    2007-01-01

    In order to study the factors affecting preferential flow,a 2.9 m-long,2.6 m-deep soil profile was dug in the Quxi watershed,Yangtze River.To analyze the influence of rainfall on preferential flow,the preferential flow process was observed when the rainfalls were recorded.Soil physical and infiltration characteristics were also measured to study their effect on preferential flow.The results showed that the rainfall amount that could cause preferential flow was over 26 mm.There are four types of rainfall in the Three Gorges area,namely gradually dropping rain,even rain,sudden rain and peak rain.Preferential flow process was found to be relevant to the rainfall process.It was determined that with different rainfall types,preferential flow appeared at different times,occurring first in peak rain,followed by sudden rain,gradually dropping rain,and then even rain.Preferential flow would appear when the rainfall intensity was over 0.075 mm/min.In the studied area,the coarse soil particles increased with the soil depth,and for the deeper soil layer,the coarse particles promote the formation of preferential flow.Preferential flow accelerates the steady infiltration rate in the 83-110 cm soil horizon,and the quickly moving water in this horizon also enhanced the further formation and development of preferential flow.

  17. Protein-solvent preferential interactions, protein hydration, and the modulation of biochemical reactions by solvent components.

    Science.gov (United States)

    Timasheff, Serge N

    2002-07-23

    Solvent additives (cosolvents, osmolytes) modulate biochemical reactions if, during the course of the reaction, there is a change in preferential interactions of solvent components with the reacting system. Preferential interactions can be expressed in terms of preferential binding of the cosolvent or its preferential exclusion (preferential hydration). The driving force is the perturbation by the protein of the chemical potential of the cosolvent. It is shown that the measured change of the amount of water in contact with protein during the course of the reaction modulated by an osmolyte is a change in preferential hydration that is strictly a measure of the cosolvent chemical potential perturbation by the protein in the ternary water-protein-cosolvent system. It is not equal to the change in water of hydration, because water of hydration is a reflection strictly of protein-water forces in a binary system. There is no direct relation between water of preferential hydration and water of hydration.

  18. Monkeys preferentially process body information while viewing affective displays.

    Science.gov (United States)

    Bliss-Moreau, Eliza; Moadab, Gilda; Machado, Christopher J

    2017-08-01

    Despite evolutionary claims about the function of facial behaviors across phylogeny, rarely are those hypotheses tested in a comparative context-that is, by evaluating how nonhuman animals process such behaviors. Further, while increasing evidence indicates that humans make meaning of faces by integrating contextual information, including that from the body, the extent to which nonhuman animals process contextual information during affective displays is unknown. In the present study, we evaluated the extent to which rhesus macaques (Macaca mulatta) process dynamic affective displays of conspecifics that included both facial and body behaviors. Contrary to hypotheses that they would preferentially attend to faces during affective displays, monkeys looked for longest, most frequently, and first at conspecifics' bodies rather than their heads. These findings indicate that macaques, like humans, attend to available contextual information during the processing of affective displays, and that the body may also be providing unique information about affective states. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Network evolution by nonlinear preferential rewiring of edges

    Science.gov (United States)

    Xu, Xin-Jian; Hu, Xiao-Ming; Zhang, Li-Jie

    2011-06-01

    The mathematical framework for small-world networks proposed in a seminal paper by Watts and Strogatz sparked a widespread interest in modeling complex networks in the past decade. However, most of research contributing to static models is in contrast to real-world dynamic networks, such as social and biological networks, which are characterized by rearrangements of connections among agents. In this paper, we study dynamic networks evolved by nonlinear preferential rewiring of edges. The total numbers of vertices and edges of the network are conserved, but edges are continuously rewired according to the nonlinear preference. Assuming power-law kernels with exponents α and β, the network structures in stationary states display a distinct behavior, depending only on β. For β>1, the network is highly heterogeneous with the emergence of starlike structures. For β<1, the network is widely homogeneous with a typical connectivity. At β=1, the network is scale free with an exponential cutoff.

  20. Preferential rifting of continents - A source of displaced terranes

    Science.gov (United States)

    Vink, G. E.; Morgan, W. J.; Zhao, W.-L.

    1984-01-01

    Lithospheric rifting, while prevalent in the continents, rarely occurs in oceanic regions. To explain this preferential rifting of continents, the total strength of different lithospheres is compared by integrating the limits of lithospheric stress with depth. Comparisons of total strength indicate that continental lithosphere is weaker than oceanic lithosphere by about a factor of three. Also, a thickened crust can halve the total strength of normal continental lithosphere. Because the weakest area acts as a stress guide, any rifting close to an ocean-continent boundary would prefer a continental pathway. This results in the formation of small continental fragments or microplates that, once accreted back to a continent during subduction, are seen as displaced terranes. In addition, the large crustal thicknesses associated with suture zones would make such areas likely locations for future rifting episodes. This results in the tendency of new oceans to open along the suture where a former ocean had closed.

  1. Seeking a preferential option for the rural poor in Chile

    Directory of Open Access Journals (Sweden)

    Edward Dew

    2006-01-01

    Full Text Available From colonial times well into the twentieth century (and, unfortunately, even beyond the man/land relationship in Latin America has been markedly unjust. Small numbers of families have owned large tracts of the best land, while large numbers of poor families have struggled with tiny plots of marginal land or labored on the estates of the rich. Chile was no exception to this pattern. Thus, its experiment with land reform in the 1960s and 1970s, the setback of reform under the military in the 1970s and 1980s, and the resumption of reform under democrats in the 1990s, may provide lessons for the rest of Latin America. Is a preferential option for the rural poor still possible in a neoliberal economic system? In Chile, the answer is a qualified “yes”

  2. Personalized recommendation based on preferential bidirectional mass diffusion

    Science.gov (United States)

    Chen, Guilin; Gao, Tianrun; Zhu, Xuzhen; Tian, Hui; Yang, Zhao

    2017-03-01

    Recommendation system provides a promising way to alleviate the dilemma of information overload. In physical dynamics, mass diffusion has been used to design effective recommendation algorithms on bipartite network. However, most of the previous studies focus overwhelmingly on unidirectional mass diffusion from collected objects to uncollected objects, while overlooking the opposite direction, leading to the risk of similarity estimation deviation and performance degradation. In addition, they are biased towards recommending popular objects which will not necessarily promote the accuracy but make the recommendation lack diversity and novelty that indeed contribute to the vitality of the system. To overcome the aforementioned disadvantages, we propose a preferential bidirectional mass diffusion (PBMD) algorithm by penalizing the weight of popular objects in bidirectional diffusion. Experiments are evaluated on three benchmark datasets (Movielens, Netflix and Amazon) by 10-fold cross validation, and results indicate that PBMD remarkably outperforms the mainstream methods in accuracy, diversity and novelty.

  3. Predicting Alcohol, Cigarette, and Marijuana Use From Preferential Music Consumption.

    Science.gov (United States)

    Oberle, Crystal D; Garcia, Javier A

    2015-01-01

    This study investigated whether use of alcohol, cigarettes, and marijuana may be predicted from preferential consumption of particular music genres. Undergraduates (257 women and 78 men) completed a questionnaire assessing these variables. Partial correlation analyses, controlling for sensation-seeking tendencies and behaviors, revealed that listening to conventional music (pop, country, and religious genres) was negatively correlated with cigarette smoking (p=.001) and marijuana use (pmusic (rap or hip-hop and soul or funk genres) was positively correlated with marijuana use (p=.004). The only significant predictor of alcohol use was country music, with which it was positively correlated (p=.04). This research suggests an especially harmful influence of energetic music on marijuana use. © The Author(s) 2015.

  4. A preferential coating technique for fabricating large, high quality optics

    International Nuclear Information System (INIS)

    Alcock, S.G.; Cockerton, S.

    2010-01-01

    A major challenge facing optic manufacturers is the fabrication of large mirrors (>1 m) with minimal residual slope errors (<0.5 μrad rms). We present a differential coating method with the potential to satisfy such exacting technical demands. Iterative cycles of measurement using the Diamond-NOM, followed by preferential deposition, were performed on a 1200 mm long, silicon mirror. The applied coatings were observed to reduce the optical slope and figure errors from 1.62 to 0.44 μrad rms, and from 208 to 13 nm rms, respectively. It is hoped that this research will lead to commercially available products, of direct benefit to the Synchrotron, Free Electron Laser, Astronomy, Space, and Laser communities, who all require state-of-the-art optics.

  5. An algorithm for preferential selection of spectroscopic targets in LEGUE

    International Nuclear Information System (INIS)

    Carlin, Jeffrey L.; Newberg, Heidi Jo; Lépine, Sébastien; Deng Licai; Chen Yuqin; Fu Xiaoting; Gao Shuang; Li Jing; Liu Chao; Beers, Timothy C.; Christlieb, Norbert; Grillmair, Carl J.; Guhathakurta, Puragra; Han Zhanwen; Hou Jinliang; Lee, Hsu-Tai; Liu Xiaowei; Pan Kaike; Sellwood, J. A.; Wang Hongchi

    2012-01-01

    We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly-varying, well-understood selection function and the desire to preferentially select certain types of targets. Some target-selection examples are shown that illustrate different possibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot survey, which began in October 2011.

  6. Preferential emission into epsilon-near-zero metamaterial [Invited

    International Nuclear Information System (INIS)

    Galfsky, Tal; Sun, Zheng; Jacob, Zubin; Menon, Vinod M.

    2015-01-01

    We report the use of epsilon near zero (ENZ) metamaterial to control spontaneous emission from Zinc-Oxide (ZnO) excitons. The ENZ material consists of alternating layers of silver and alumina with subwavelength thicknesses, resulting in an effective medium where one of the components of the dielectric constant approach zero between 370nm-440nm wavelength range. Bulk ZnO with photoluminescence maximum in the ENZ regime was deposited via atomic layer deposition to obtain a smooth film with near field coupling to the ENZ metamaterial. Preferential emission from the ZnO layer into the metamaterial with suppression of forward emission by 90% in comparison to ZnO on silicon is observed. We attribute this observation to the presence of dispersionless plasmonic modes in the ENZ regime as shown by the results of theoretical modeling presented here. Integration of ENZ metamaterials with light emitters is an attractive platform for realizing a low threshold subwavelength laser

  7. Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

    Directory of Open Access Journals (Sweden)

    Miyabara E.H.

    2005-01-01

    Full Text Available Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA, on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001 and CsA significantly reduced the body weight gain (15.5%; P = 0.01 during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29%, respectively, P < 0.05. CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001. Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

  8. Organization of growing random networks

    International Nuclear Information System (INIS)

    Krapivsky, P. L.; Redner, S.

    2001-01-01

    The organizational development of growing random networks is investigated. These growing networks are built by adding nodes successively, and linking each to an earlier node of degree k with an attachment probability A k . When A k grows more slowly than linearly with k, the number of nodes with k links, N k (t), decays faster than a power law in k, while for A k growing faster than linearly in k, a single node emerges which connects to nearly all other nodes. When A k is asymptotically linear, N k (t)∼tk -ν , with ν dependent on details of the attachment probability, but in the range 2 -2 power-law tail, where s is the component size. The out component has a typical size of order lnt, and it provides basic insights into the genealogy of the network

  9. Coercion, autonomy, and the preferential option for the poor in the ethics of organ transplantation.

    Science.gov (United States)

    Jaycox, Michael P

    2012-12-01

    The debate concerning whether to legalize and regulate the global market in human organs is hindered by a lack of adequate bioethical language. The author argues that the preferential option for the poor, a theological category, can provide the grounding for an inductive moral epistemology adequate for reforming the use of culturally Western bioethical language. He proposes that the traditional, Western concept of bioethical coercion ought to be modified and expanded because the conditions of the market system, as viewed from the perspective of organ vendors systemically deprived of access to sufficient resources, are sufficiently exploitative as to diminish the possibility of these vendors giving informed consent. Moreover, empirical studies conducted by professionals in medicine, sociology, psychiatry, economics, and medical anthropology continue to contribute support to the growing interdisciplinary consensus that functionally coercive structural factors exert the most significant influence upon a vendor's decision to sell an organ within any market, regardless of legality or degree of regulation. Therefore any proposal to legalize and regulate the organ market remains patently unethical because doing so would likely function to constrain further the agency of poor potential vendors. © 2012 Blackwell Publishing Ltd.

  10. Preferential inclusion of extrachromosomal genetic elements in yeast meiotic spores.

    Science.gov (United States)

    Brewer, B J; Fangman, W L

    1980-09-01

    During meiosis and sporulation in the yeast Saccharomyces cerevisiae, extrachromosomal traits are efficiently transmitted to haploid spores. Although the pattern of inheritance of chromosomal traits reflects the mechanism of regular chromosomal segregation in meiosis, it is not known what processes are reflected by the efficient inheritance of extrachromosomal traits. Because extrachromosomal genetic elements in yeast are present in multiple copies, perpetuation of an extrachromosomal trait could occur by the passive envelopment of a subset of copies or by an active sequestering of all or a subset of copies within the four spores. We show that only subsets of the four extrachromosomal nucleic acids commonly found in yeast are transmitted through meiosis--55% of mitochondrial DNA copies, 82% of the 2-micron DNA plasmids, and about 70% of the L and M double-stranded RNAs. However, electron micrographs of serial sections through yeast asci indicate that the four spore enclose only 30% of the total ascus material. Thus these extrachromosomal elements are preferentially included within the spores, indicating that their inheritance is not a random process. Transmission of mitochondrial DNA can be accounted for by the observed enclosure of 52% of the mitochondrial volume within the spores. The high transmission frequencies of the double-stranded RNAs (which exist as virus-like particles in the cytoplasm) and 2-micron DNA must indicate that either these nucleic acids are actively recruited from the cytoplasm by some mechanism or they are associated in some way with the nucleus during meiosis.

  11. Maximum entropy networks are more controllable than preferential attachment networks

    International Nuclear Information System (INIS)

    Hou, Lvlin; Small, Michael; Lao, Songyang

    2014-01-01

    A maximum entropy (ME) method to generate typical scale-free networks has been recently introduced. We investigate the controllability of ME networks and Barabási–Albert preferential attachment networks. Our experimental results show that ME networks are significantly more easily controlled than BA networks of the same size and the same degree distribution. Moreover, the control profiles are used to provide insight into control properties of both classes of network. We identify and classify the driver nodes and analyze the connectivity of their neighbors. We find that driver nodes in ME networks have fewer mutual neighbors and that their neighbors have lower average degree. We conclude that the properties of the neighbors of driver node sensitively affect the network controllability. Hence, subtle and important structural differences exist between BA networks and typical scale-free networks of the same degree distribution. - Highlights: • The controllability of maximum entropy (ME) and Barabási–Albert (BA) networks is investigated. • ME networks are significantly more easily controlled than BA networks of the same degree distribution. • The properties of the neighbors of driver node sensitively affect the network controllability. • Subtle and important structural differences exist between BA networks and typical scale-free networks

  12. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium

    International Nuclear Information System (INIS)

    Lipinski, Michael J.; Albelda, M. Teresa; Frias, Juan C.; Anderson, Stasia A.; Luger, Dror; Westman, Peter C.; Escarcega, Ricardo O.; Hellinga, David G.; Waksman, Ron; Arai, Andrew E.; Epstein, Stephen E.

    2016-01-01

    Introduction: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia–reperfusion murine myocardial infarction model. Methods: Mice underwent ischemia–reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24 h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. Results: The mean size of the liposomes was 100 nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163 ± 31% vs. 13 ± 14%, p = 0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Conclusions: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.

  13. Effect of reactor heat transfer limitations on CO preferential oxidation

    Science.gov (United States)

    Ouyang, X.; Besser, R. S.

    Our recent studies of CO preferential oxidation (PrOx) identified systematic differences between the characteristic curves of CO conversion for a microchannel reactor with thin-film wall catalyst and conventional mini packed-bed lab reactors (m-PBR's). Strong evidence has suggested that the reverse water-gas-shift (r-WGS) side reaction activated by temperature gradients in m-PBR's is the source of these differences. In the present work, a quasi-3D tubular non-isothermal reactor model based on the finite difference method was constructed to quantitatively study the effect of heat transport resistance on PrOx reaction behavior. First, the kinetic expressions for the three principal reactions involved were formed based on the combination of experimental data and literature reports and their parameters were evaluated with a non-linear regression method. Based on the resulting kinetic model and an energy balance derived for PrOx, the finite difference method was then adopted for the quasi-3D model. This model was then used to simulate both the microreactor and m-PBR's and to gain insights into their different conversion behavior. Simulation showed that the temperature gradients in m-PBR's favor the reverse water-gas-shift (r-WGS) reaction, thus causing a much narrower range of permissible operating temperature compared to the microreactor. Accordingly, the extremely efficient heat removal of the microchannel/thin-film catalyst system eliminates temperature gradients and efficiently prevents the onset of the r-WGS reaction.

  14. Short-ranged memory model with preferential growth

    Science.gov (United States)

    Schaigorodsky, Ana L.; Perotti, Juan I.; Almeira, Nahuel; Billoni, Orlando V.

    2018-02-01

    In this work we introduce a variant of the Yule-Simon model for preferential growth by incorporating a finite kernel to model the effects of bounded memory. We characterize the properties of the model combining analytical arguments with extensive numerical simulations. In particular, we analyze the lifetime and popularity distributions by mapping the model dynamics to corresponding Markov chains and branching processes, respectively. These distributions follow power laws with well-defined exponents that are within the range of the empirical data reported in ecologies. Interestingly, by varying the innovation rate, this simple out-of-equilibrium model exhibits many of the characteristics of a continuous phase transition and, around the critical point, it generates time series with power-law popularity, lifetime and interevent time distributions, and nontrivial temporal correlations, such as a bursty dynamics in analogy with the activity of solar flares. Our results suggest that an appropriate balance between innovation and oblivion rates could provide an explanatory framework for many of the properties commonly observed in many complex systems.

  15. Functional hierarchy underlies preferential connectivity disturbances in schizophrenia.

    Science.gov (United States)

    Yang, Genevieve J; Murray, John D; Wang, Xiao-Jing; Glahn, David C; Pearlson, Godfrey D; Repovs, Grega; Krystal, John H; Anticevic, Alan

    2016-01-12

    Schizophrenia may involve an elevated excitation/inhibition (E/I) ratio in cortical microcircuits. It remains unknown how this regulatory disturbance maps onto neuroimaging findings. To address this issue, we implemented E/I perturbations within a neural model of large-scale functional connectivity, which predicted hyperconnectivity following E/I elevation. To test predictions, we examined resting-state functional MRI in 161 schizophrenia patients and 164 healthy subjects. As predicted, patients exhibited elevated functional connectivity that correlated with symptom levels, and was most prominent in association cortices, such as the fronto-parietal control network. This pattern was absent in patients with bipolar disorder (n = 73). To account for the pattern observed in schizophrenia, we integrated neurobiologically plausible, hierarchical differences in association vs. sensory recurrent neuronal dynamics into our model. This in silico architecture revealed preferential vulnerability of association networks to E/I imbalance, which we verified empirically. Reported effects implicate widespread microcircuit E/I imbalance as a parsimonious mechanism for emergent inhomogeneous dysconnectivity in schizophrenia.

  16. Multimodality imaging demonstrates trafficking of liposomes preferentially to ischemic myocardium

    Energy Technology Data Exchange (ETDEWEB)

    Lipinski, Michael J., E-mail: mjlipinski12@gmail.com [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Albelda, M. Teresa [GIBI2" 3" 0, Grupo de Investigación Biomédica en Imagen, IIS La Fe, Valencia (Spain); Frias, Juan C. [Departamento de Ciencias Biomédicas, Universidad CEU Cardenal Herrera, Valencia (Spain); Anderson, Stasia A. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Luger, Dror; Westman, Peter C.; Escarcega, Ricardo O.; Hellinga, David G.; Waksman, Ron [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States); Arai, Andrew E. [Advanced Cardiovascular Imaging Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Epstein, Stephen E. [MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC (United States)

    2016-03-15

    Introduction: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia–reperfusion murine myocardial infarction model. Methods: Mice underwent ischemia–reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24 h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. Results: The mean size of the liposomes was 100 nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163 ± 31% vs. 13 ± 14%, p = 0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. Conclusions: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.

  17. Growing Oppression, Growing Resistance : LGBT Activism and Europeanisation in Macedonia

    NARCIS (Netherlands)

    Miškovska Kajevska, A.; Bilić, B.

    2016-01-01

    This chapter provides one of the first socio-historical overviews of the LGBT groups in Macedonia and argues that an important impetus for the proliferation of LGBT activities has been the growing state-endorsed homophobia starting from 2008. The homophobic rhetoric of the ruling parties was clearly

  18. Cheap heat grows in fields

    International Nuclear Information System (INIS)

    Haluza, I.

    2006-01-01

    Slovak farmers resemble the peasants from the film T he Magnificent Seven . They keep complaining about their fate but consider any innovation as an interference. And that is why they still have not started growing fast-growing wood although the number of heating plants processing bio-mass from forests and fields is growing. Natural gas is expensive and coal creates pollution. Energy from biomass is becoming a good business and also creates new business opportunities - growing the raw material it needs. Such heating plants usually use waste from wood processing companies and Slovak Forests (Lesy SR) has also started deliveries of chip wood from old forests. There are plantations of fast growing wood suitable for heat production of over 500-thousand hectares throughout the EU. This is about 10% of Slovakian's area where the first plantations are also already being set up. The first promising plantation project was launched this spring. And this is not a project launched and backed by a big company but a starting up businessman, Miroslav Forgac from Kosice. He founded his company, Forgim, last winter. Without big money involved and thank to a new business idea he managed to persuade farmers to set up the first plantations. He supplied the seedlings and the business has started with 75 ha of plantations around Trnava, Sala, Komarno, Lucenec, Poprad and Kosice. He is gradually signing contracts with other landowners and next year the area of plantations is set to grow by 1500 ha. Plantations of fast growing trees such as willow, poplar and acacia regenerate by new trees growing out of the roots of the old and from cut trees so from one seedling and one investment there can be several harvests. Swedish willows from Forgim regenerate 20 to 25 years after the first planting. And only then new seedlings have to be purchased. Using special machines that even cut the wood to wood chips the plantations can be 'harvested' every three years. Unlike crops, the fields do not

  19. Partial preferential chromosome pairing is genotype dependent in tetraploid rose.

    Science.gov (United States)

    Bourke, Peter M; Arens, Paul; Voorrips, Roeland E; Esselink, G Danny; Koning-Boucoiran, Carole F S; Van't Westende, Wendy P C; Santos Leonardo, Tiago; Wissink, Patrick; Zheng, Chaozhi; van Geest, Geert; Visser, Richard G F; Krens, Frans A; Smulders, Marinus J M; Maliepaard, Chris

    2017-04-01

    It has long been recognised that polyploid species do not always neatly fall into the categories of auto- or allopolyploid, leading to the term 'segmental allopolyploid' to describe everything in between. The meiotic behaviour of such intermediate species is not fully understood, nor is there consensus as to how to model their inheritance patterns. In this study we used a tetraploid cut rose (Rosa hybrida) population, genotyped using the 68K WagRhSNP array, to construct an ultra-high-density linkage map of all homologous chromosomes using methods previously developed for autotetraploids. Using the predicted bivalent configurations in this population we quantified differences in pairing behaviour among and along homologous chromosomes, leading us to correct our estimates of recombination frequency to account for this behaviour. This resulted in the re-mapping of 25 695 SNP markers across all homologues of the seven rose chromosomes, tailored to the pairing behaviour of each chromosome in each parent. We confirmed the inferred differences in pairing behaviour among chromosomes by examining repulsion-phase linkage estimates, which also carry information about preferential pairing and recombination. Currently, the closest sequenced relative to rose is Fragaria vesca. Aligning the integrated ultra-dense rose map with the strawberry genome sequence provided a detailed picture of the synteny, confirming overall co-linearity but also revealing new genomic rearrangements. Our results suggest that pairing affinities may vary along chromosome arms, which broadens our current understanding of segmental allopolyploidy. © 2017 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

  20. Frac Sand Mines Are Preferentially Sited in Unzoned Rural Areas.

    Directory of Open Access Journals (Sweden)

    Christina Locke

    Full Text Available Shifting markets can cause unexpected, stochastic changes in rural landscapes that may take local communities by surprise. Preferential siting of new industrial facilities in poor areas or in areas with few regulatory restrictions can have implications for environmental sustainability, human health, and social justice. This study focuses on frac sand mining-the mining of high-quality silica sand used in hydraulic fracturing processes for gas and oil extraction. Frac sand mining gained prominence in the 2000s in the upper midwestern United States where nonmetallic mining is regulated primarily by local zoning. I asked whether frac sand mines were more commonly sited in rural townships without formal zoning regulations or planning processes than in those that undertook zoning and planning before the frac sand boom. I also asked if mine prevalence was correlated with socioeconomic differences across townships. After creating a probability surface to map areas most suitable for frac sand mine occurrence, I developed neutral landscape models from which to compare actual mine distributions in zoned and unzoned areas at three different spatial extents. Mines were significantly clustered in unzoned jurisdictions at the statewide level and in 7 of the 8 counties with at least three frac sand mines and some unzoned land. Subsequent regression analyses showed mine prevalence to be uncorrelated with land value, tax rate, or per capita income, but correlated with remoteness and zoning. The predicted mine count in unzoned townships was over two times higher than that in zoned townships. However, the county with the most mines by far was under a county zoning ordinance, perhaps indicating industry preferences for locations with clear, homogenous rules over patchwork regulation. Rural communities can use the case of frac sand mining as motivation to discuss and plan for sudden land-use predicaments, rather than wait to grapple with unfamiliar legal processes

  1. Frac Sand Mines Are Preferentially Sited in Unzoned Rural Areas.

    Science.gov (United States)

    Locke, Christina

    2015-01-01

    Shifting markets can cause unexpected, stochastic changes in rural landscapes that may take local communities by surprise. Preferential siting of new industrial facilities in poor areas or in areas with few regulatory restrictions can have implications for environmental sustainability, human health, and social justice. This study focuses on frac sand mining-the mining of high-quality silica sand used in hydraulic fracturing processes for gas and oil extraction. Frac sand mining gained prominence in the 2000s in the upper midwestern United States where nonmetallic mining is regulated primarily by local zoning. I asked whether frac sand mines were more commonly sited in rural townships without formal zoning regulations or planning processes than in those that undertook zoning and planning before the frac sand boom. I also asked if mine prevalence was correlated with socioeconomic differences across townships. After creating a probability surface to map areas most suitable for frac sand mine occurrence, I developed neutral landscape models from which to compare actual mine distributions in zoned and unzoned areas at three different spatial extents. Mines were significantly clustered in unzoned jurisdictions at the statewide level and in 7 of the 8 counties with at least three frac sand mines and some unzoned land. Subsequent regression analyses showed mine prevalence to be uncorrelated with land value, tax rate, or per capita income, but correlated with remoteness and zoning. The predicted mine count in unzoned townships was over two times higher than that in zoned townships. However, the county with the most mines by far was under a county zoning ordinance, perhaps indicating industry preferences for locations with clear, homogenous rules over patchwork regulation. Rural communities can use the case of frac sand mining as motivation to discuss and plan for sudden land-use predicaments, rather than wait to grapple with unfamiliar legal processes during a period of

  2. Exploring Classroom Hydroponics. Growing Ideas.

    Science.gov (United States)

    National Gardening Association, Burlington, VT.

    Growing Ideas, the National Gardening Association's series for elementary, middle, and junior high school educators, helps teachers engage students in using plants and gardens as contexts for developing a deeper, richer understanding of the world around them. This volume's focus is on hydroponics. It presents basic hydroponics information along…

  3. Organization of growing random networks

    Energy Technology Data Exchange (ETDEWEB)

    Krapivsky, P. L.; Redner, S.

    2001-06-01

    The organizational development of growing random networks is investigated. These growing networks are built by adding nodes successively, and linking each to an earlier node of degree k with an attachment probability A{sub k}. When A{sub k} grows more slowly than linearly with k, the number of nodes with k links, N{sub k}(t), decays faster than a power law in k, while for A{sub k} growing faster than linearly in k, a single node emerges which connects to nearly all other nodes. When A{sub k} is asymptotically linear, N{sub k}(t){similar_to}tk{sup {minus}{nu}}, with {nu} dependent on details of the attachment probability, but in the range 2{lt}{nu}{lt}{infinity}. The combined age and degree distribution of nodes shows that old nodes typically have a large degree. There is also a significant correlation in the degrees of neighboring nodes, so that nodes of similar degree are more likely to be connected. The size distributions of the in and out components of the network with respect to a given node{emdash}namely, its {open_quotes}descendants{close_quotes} and {open_quotes}ancestors{close_quotes}{emdash}are also determined. The in component exhibits a robust s{sup {minus}2} power-law tail, where s is the component size. The out component has a typical size of order lnt, and it provides basic insights into the genealogy of the network.

  4. Growing an Emerging Research University

    Science.gov (United States)

    Birx, Donald L.; Anderson-Fletcher, Elizabeth; Whitney, Elizabeth

    2013-01-01

    The emerging research college or university is one of the most formidable resources a region has to reinvent and grow its economy. This paper is the first of two that outlines a process of building research universities that enhance regional technology development and facilitate flexible networks of collaboration and resource sharing. Although the…

  5. Growing Crystals on the Ceiling.

    Science.gov (United States)

    Christman, Robert A.

    1980-01-01

    Described is a method of studying growing crystals in a classroom utilizing a carrousel projector standing vertically. A saturated salt solution is placed on a slide on the lens of the projector and the heat from the projector causes the water to evaporate and salt to crystalize. (Author/DS)

  6. Agglomerative clustering of growing squares

    NARCIS (Netherlands)

    Castermans, Thom; Speckmann, Bettina; Staals, Frank; Verbeek, Kevin; Bender, M.A.; Farach-Colton, M.; Mosteiro, M.A.

    2018-01-01

    We study an agglomerative clustering problem motivated by interactive glyphs in geo-visualization. Consider a set of disjoint square glyphs on an interactive map. When the user zooms out, the glyphs grow in size relative to the map, possibly with different speeds. When two glyphs intersect, we wish

  7. Inferences from growing trees backwards

    Science.gov (United States)

    David W. Green; Kent A. McDonald

    1997-01-01

    The objective of this paper is to illustrate how longitudinal stress wave techniques can be useful in tracking the future quality of a growing tree. Monitoring the quality of selected trees in a plantation forest could provide early input to decisions on the effectiveness of management practices, or future utilization options, for trees in a plantation. There will...

  8. COFFEE GROWING AREAS OF ETHIOPIA"

    African Journals Online (AJOL)

    accelerated economic growth, part of which is hoped to be achieved via increased ... at the Fifth International Conference on the Ethiopian Economy held at the United ... Samuel and Ludi: Agricultural commercialisation in coffee growing areas. ... Ethiopia produces and exports one of the best fighland coffees in the world.

  9. Your Health Buddies Matter: Preferential Selection and Social Influence on Weight Management in an Online Health Social Network.

    Science.gov (United States)

    Meng, Jingbo

    2016-12-01

    A growing number of online social networks are designed with the intention to promote health by providing virtual space wherein individuals can seek and share information and support with similar others. Research has shown that real-world social networks have a significant influence on one's health behavior and outcomes. However, there is a dearth of studies on how individuals form social networks in virtual space and whether such online social networks exert any impact on individuals' health outcomes. Built on the Multi-Theoretical Multilevel (MTML) framework and drawing from literature on social influence, this study examined the mechanisms underlying the formation of an online health social network and empirically tested social influence on individual health outcomes through the network. Situated in a weight management social networking site, the study tracked a health buddy network of 709 users and their weight management activities and outcomes for 4 months. Actor-based modeling was used to test the joint dynamics of preferential selection and social influence among health buddies. The results showed that baseline, inbreeding, and health status homophily significantly predicted preferential selection of health buddies in the weight management social networking site, whereas self-interest in seeking experiential health information did not. The study also found peer influence of online health buddy networks on individual weight outcomes, such that an individual's odds of losing weight increased if, on average, the individual's health buddies were losing weight.

  10. Preferential flow in water-repellent sandy soils : model development and lysimeter experiments

    NARCIS (Netherlands)

    Rooij, de G.H.

    1996-01-01


    When water enters a water-repellent topsoil, preferential flow paths develop and the flow bypasses a large part of the unsaturated zone. Therefore, preferential flow caused by water- repellency is expected to accelerate solute leaching to the groundwater. In soils with water-repellent

  11. Spreading dynamics of an e-commerce preferential information model on scale-free networks

    Science.gov (United States)

    Wan, Chen; Li, Tao; Guan, Zhi-Hong; Wang, Yuanmei; Liu, Xiongding

    2017-02-01

    In order to study the influence of the preferential degree and the heterogeneity of underlying networks on the spread of preferential e-commerce information, we propose a novel susceptible-infected-beneficial model based on scale-free networks. The spreading dynamics of the preferential information are analyzed in detail using the mean-field theory. We determine the basic reproductive number and equilibria. The theoretical analysis indicates that the basic reproductive number depends mainly on the preferential degree and the topology of the underlying networks. We prove the global stability of the information-elimination equilibrium. The permanence of preferential information and the global attractivity of the information-prevailing equilibrium are also studied in detail. Some numerical simulations are presented to verify the theoretical results.

  12. Dynamics of epidemic diseases on a growing adaptive network.

    Science.gov (United States)

    Demirel, Güven; Barter, Edmund; Gross, Thilo

    2017-02-10

    The study of epidemics on static networks has revealed important effects on disease prevalence of network topological features such as the variance of the degree distribution, i.e. the distribution of the number of neighbors of nodes, and the maximum degree. Here, we analyze an adaptive network where the degree distribution is not independent of epidemics but is shaped through disease-induced dynamics and mortality in a complex interplay. We study the dynamics of a network that grows according to a preferential attachment rule, while nodes are simultaneously removed from the network due to disease-induced mortality. We investigate the prevalence of the disease using individual-based simulations and a heterogeneous node approximation. Our results suggest that in this system in the thermodynamic limit no epidemic thresholds exist, while the interplay between network growth and epidemic spreading leads to exponential networks for any finite rate of infectiousness when the disease persists.

  13. KEPLER EXOPLANET CANDIDATE HOST STARS ARE PREFERENTIALLY METAL RICH

    International Nuclear Information System (INIS)

    Schlaufman, Kevin C.; Laughlin, Gregory

    2011-01-01

    We find that Kepler exoplanet candidate (EC) host stars are preferentially metal rich, including the low-mass stellar hosts of small-radius ECs. The last observation confirms a tentative hint that there is a correlation between the metallicity of low-mass stars and the presence of low-mass and small-radius exoplanets. In particular, we compare the J-H-g-r color-color distribution of Kepler EC host stars with a control sample of dwarf stars selected from the ∼150, 000 stars observed during Q1 and Q2 of the Kepler mission but with no detected planets. We find that at J - H = 0.30 characteristic of solar-type stars, the average g-r color of stars that host giant ECs is 4σ redder than the average color of the stars in the control sample. At the same J - H color, the average g-r color of solar-type stars that host small-radius ECs is indistinguishable from the average color of the stars in the control sample. In addition, we find that at J - H = 0.62 indicative of late K dwarfs, the average g-r color of stars that host small-radius ECs is 4σ redder than the average color of the stars in the control sample. These offsets are unlikely to be caused by differential reddening, age differences between the two populations, or the presence of giant stars in the control sample. Stellar models suggest that the first color offset is due to a 0.2 dex enhancement in [Fe/H] of the giant EC host population at M * ∼ 1 M sun , while Sloan photometry of M 67 and NGC 6791 suggests that the second color offset is due to a similar [Fe/H] enhancement of the small-radius EC host population at M * ∼ 0.7 M sun . These correlations are a natural consequence of the core-accretion model of planet formation.

  14. Stream Clustering of Growing Objects

    Science.gov (United States)

    Siddiqui, Zaigham Faraz; Spiliopoulou, Myra

    We study incremental clustering of objects that grow and accumulate over time. The objects come from a multi-table stream e.g. streams of Customer and Transaction. As the Transactions stream accumulates, the Customers’ profiles grow. First, we use an incremental propositionalisation to convert the multi-table stream into a single-table stream upon which we apply clustering. For this purpose, we develop an online version of K-Means algorithm that can handle these swelling objects and any new objects that arrive. The algorithm also monitors the quality of the model and performs re-clustering when it deteriorates. We evaluate our method on the PKDD Challenge 1999 dataset.

  15. Millennium bim managing growing demand

    OpenAIRE

    Lopes, Francisca Barbosa Malpique de Paiva

    2014-01-01

    Millennium bim, the Mozambican operation of Millennium bcp group, was the Company selected to serve as background for the development of a teaching case in Marketing. This case is followed by a teaching note, and is intended to be used as a pedagogical tool in undergraduate and/or graduate programs. Even though Mozambique is still characterized by high financial exclusion, the number of people entering within the banking industry has been growing at a fast pace. Actually, the demand for fi...

  16. How do normal faults grow?

    OpenAIRE

    Blækkan, Ingvild; Bell, Rebecca; Rotevatn, Atle; Jackson, Christopher; Tvedt, Anette

    2018-01-01

    Faults grow via a sympathetic increase in their displacement and length (isolated fault model), or by rapid length establishment and subsequent displacement accrual (constant-length fault model). To test the significance and applicability of these two models, we use time-series displacement (D) and length (L) data extracted for faults from nature and experiments. We document a range of fault behaviours, from sympathetic D-L fault growth (isolated growth) to sub-vertical D-L growth trajectorie...

  17. Tannic Acid Preferentially Targets Estrogen Receptor-Positive Breast Cancer

    Directory of Open Access Journals (Sweden)

    Brian W. Booth

    2013-01-01

    Full Text Available Research efforts investigating the potential of natural compounds in the fight against cancer are growing. Tannic acid (TA belongs to the class of hydrolysable tannins and is found in numerous plants and foods. TA is a potent collagen cross-linking agent; the purpose of this study was to generate TA-cross-linked beads and assess the effects on breast cancer cell growth. Collagen beads were stable at body temperature following crosslinking. Exposure to collagen beads with higher levels of TA inhibited proliferation and induced apoptosis in normal and cancer cells. TA-induced apoptosis involved activation of caspase 3/7 and caspase 9 but not caspase 8. Breast cancer cells expressing the estrogen receptor were more susceptible to the effects of TA. Taken together the results suggest that TA has the potential to become an anti-ER+ breast cancer treatment or preventative agent.

  18. Preferential Allele Expression Analysis Identifies Shared Germline and Somatic Driver Genes in Advanced Ovarian Cancer

    Science.gov (United States)

    Halabi, Najeeb M.; Martinez, Alejandra; Al-Farsi, Halema; Mery, Eliane; Puydenus, Laurence; Pujol, Pascal; Khalak, Hanif G.; McLurcan, Cameron; Ferron, Gwenael; Querleu, Denis; Al-Azwani, Iman; Al-Dous, Eman; Mohamoud, Yasmin A.; Malek, Joel A.; Rafii, Arash

    2016-01-01

    Identifying genes where a variant allele is preferentially expressed in tumors could lead to a better understanding of cancer biology and optimization of targeted therapy. However, tumor sample heterogeneity complicates standard approaches for detecting preferential allele expression. We therefore developed a novel approach combining genome and transcriptome sequencing data from the same sample that corrects for sample heterogeneity and identifies significant preferentially expressed alleles. We applied this analysis to epithelial ovarian cancer samples consisting of matched primary ovary and peritoneum and lymph node metastasis. We find that preferentially expressed variant alleles include germline and somatic variants, are shared at a relatively high frequency between patients, and are in gene networks known to be involved in cancer processes. Analysis at a patient level identifies patient-specific preferentially expressed alleles in genes that are targets for known drugs. Analysis at a site level identifies patterns of site specific preferential allele expression with similar pathways being impacted in the primary and metastasis sites. We conclude that genes with preferentially expressed variant alleles can act as cancer drivers and that targeting those genes could lead to new therapeutic strategies. PMID:26735499

  19. Dental implants in growing children

    Directory of Open Access Journals (Sweden)

    S K Mishra

    2013-01-01

    Full Text Available The replacement of teeth by implants is usually restricted to patients with completed craniofacial growth. The aim of this literature review is to discuss the use of dental implants in normal growing patients and in patients with ectodermal dysplasia and the influence of maxillary and mandibular skeletal and dental growth on the stability of those implants. It is recommended that while deciding the optimal individual time point of implant insertion, the status of skeletal growth, the degree of hypodontia, and extension of related psychological stress should be taken into account, in addition to the status of existing dentition and dental compliance of a pediatric patient.

  20. Torsion of a growing shaft

    Directory of Open Access Journals (Sweden)

    Alexander V. Manzhirov

    2017-12-01

    Full Text Available The torsion of a shaft by rigid disks is considered. The shaft has the form of circular cylinder. Two rigid disks are attached to its end faces. The process of continuous growth of such shaft under the influence of twisting torques applied to the disks is studied. Dual series equations which reflect the mathematical content of the problem at the different stages of the growing process are derived and solved. Results of the numerical analysis and singularities of the qualitative mechanical behaviour of the fundamental characteristics are discussed.

  1. Growing energy demand - environmental impact

    International Nuclear Information System (INIS)

    Rama Rao, G.A.

    2012-01-01

    Scientists can bring information, insights, and analytical skills to bear on matters of public concern. Often they can help the public and its representatives to understand the likely causes of events (such as natural and technological disasters) and to estimate the possible effects of projected policies. Often they can testify to what is not possible. Even so, scientists can seldom bring definitive answers to matters of public debate. Some issues are too complex to fit within the current scope of science, or there may be little reliable information available, or the values involved may lie outside of science. Scientists and technologists strive to find an answer to the growing energy demand

  2. How fast do eels grow

    International Nuclear Information System (INIS)

    Hansen, H.J.M.

    1988-01-01

    Not so very much about the growth pattern of the eel is known yet. Eels move about nearly all the time. They are thus very difficult to follow and we do not, for examble, yet know how long it actually takes for them to grow to maturity in the wild. So far, a macroscopic analysis of the number of bright and dark areas (growth rings) in the 'earstones' has been used to determine eel age, but this method was recently challenged. Use of radioisotopes has been suggested previously for this purpose. For this present study the rare earth elements, europium-152 and europium-155 are used. When incubated in artificial sea water, a satisfactory final radioactive label was achieved. Two experiments were planned in collaboration with the Swedish Environmental Protection Agency. 2000 Elvers were set out in 1982, in the cooling water outlet of the Oskarshamn nuclear power plant, each marked with europium-155. In 1984 another 10 000 elvers labelled with europium-152 were set out under similar conditions. The idea was mainly to see how fast the eels would grow, and to compare their known age with that determined by examining the earstones. Results showed that there was no clear-cut correlation between actual eel age and the biological age determination used so far. During four years, only 10 of the original 1300 eels were recaptured. It is thus hard to say anything definite from our results on the viability of setting out elvers in the environment

  3. Preferential Price and Trade Tied Aid in Fiji: Implications on Price ...

    African Journals Online (AJOL)

    Pacific island countries (PICs) have been receiving the highest percapita aid .... dimension of the preferential price by examining the role of forecast price as an ..... Abbot, D and S. Pollard (2004) Hardship and Poverty in the Pacific, Asian.

  4. Inert Carbon Nanoparticles for the Assessment of Preferential Flow in Saturated Dual-Permeability Porous Media

    KAUST Repository

    Yao, Chuanjin; Zhao, Yushi; Lei, Guanglun; Steenhuis, Tammo S.; Cathles, Lawrence M.

    2017-01-01

    appropriately, nanoparticles together with a chemical tracer can assess the preferential flow in heterogeneous environments. The results also implement the dual tracer tests in heterogeneous environments by simultaneously injecting chemical and nanoparticle

  5. A summary of the theory of the preferential sputtering of alloys

    International Nuclear Information System (INIS)

    Kelly, R.; Harrison, D.E.

    1985-01-01

    Preferential sputtering of alloys arises from mass differences, chemical binding differences and bombardment-induced gibbsian segregation. The relations underlying the mass effect, the chemical binding effect and bombardment-induced gibbsian segregation in binary alloys are given. (Auth.)

  6. Viking Disruptions or Growing Integration?

    DEFF Research Database (Denmark)

    Sindbæk, Søren Michael

    2012-01-01

    Long-distance communication has emerged as a particular focus for archaeological exploration using network theory, analysis, and modelling. Initial attempts to adapt methods from social network analysis to archaeological data have, however, struggled to produce decisive results. This paper...... demonstrates how formal network analysis can be combined with a contextual reading of evidence relating to a long-distance communication network in the past. A study of the combined distributions of ten vessel types in 152 settlement sites from the 10th century suggests the outline of the core structure...... of the network. The model implies that 10th century long-distance exchange in the North Sea region featured long-distance links equal to those of the Carolingian emporia trade, and represented a growth in terms of new axes of integration, above all the growing links between the Scandinavian Peninsula...

  7. Growing the Blockchain information infrastructure

    DEFF Research Database (Denmark)

    Jabbar, Karim; Bjørn, Pernille

    2017-01-01

    In this paper, we present ethnographic data that unpacks the everyday work of some of the many infrastructuring agents who contribute to creating, sustaining and growing the Blockchain information infrastructure. We argue that this infrastructuring work takes the form of entrepreneurial actions......, which are self-initiated and primarily directed at sustaining or increasing the initiator’s stake in the emerging information infrastructure. These entrepreneurial actions wrestle against the affordances of the installed base of the Blockchain infrastructure, and take the shape of engaging...... or circumventing activities. These activities purposefully aim at either influencing or working around the enablers and constraints afforded by the Blockchain information infrastructure, as its installed base is gaining inertia. This study contributes to our understanding of the purpose of infrastructuring, seen...

  8. Supplies should match growing demand

    International Nuclear Information System (INIS)

    Rasmusen, H.J.

    1997-01-01

    The natural gas industry is currently enjoying healthy growth prospects. Not only is the demand for natural gas steadily growing; the outlook for increasing gas reserves is promising as well. The success of natural gas in the marketplace reflects, on one hand, continuous attention paid to public and customer requirements and, on the other hand, the ability of the gas industry to direct technological developments toward the increasing public demand for gas at competitive market prices supplied in a reliable, safe and environmentally friendly manner. In the past, the gas industry has been involved in the development of technologies for everything from gas production to the end user and from borehole to burner tip, and the author believes that the industry must continue or even increase its emphasis on technology in the future in order to capture new market opportunities. He explains this by looking at the supply side, the demand side and the structural side of the business

  9. How to grow great leaders.

    Science.gov (United States)

    Ready, Douglas A

    2004-12-01

    Few leaders excel at both the unit and enterprise levels. More than ever, though, corporations need people capable of running business units, functions, or regions and focusing on broader company goals. It's up to organizations to develop leaders who can manage the inherent tensions between unit and enterprise priorities. Take the example of RBC Financial Group, one of the largest, most profitable companies in Canada. In the mid-1990's, RBC revamped its competitive strategy in a couple of ways. After the government announced that the Big Six banks in Canada could neither merge with nor acquire one another, RBC decided to grow through cross-border acquisitions. Additionally, because customers were starting to seek bundled products and services, RBC reached across its traditional stand-alone businesses to offer integrated solutions. These changes in strategy didn't elicit immediate companywide support. Instinctively, employees reacted against what would amount to a delicate balancing act: They would have to lift their focus out of their silos while continuing to meet unit goals. However, by communicating extensively with staff members, cross-fertilizing talent across unit boundaries, and targeting rewards to shape performance, RBC was able to cultivate rising leaders with the unit expertise and the enterprise vision to help the company fulfill its new aims. Growing such well-rounded leaders takes sustained effort because unit-enterprise tensions are quite real. Three common conditions reinforce these tensions. First, most organizational structures foster silo thinking and unimaginative career paths. Second, most companies lack venues for airing and resolving conflicts that arise when there are competing priorities. Third, many have misguided reward systems that pit unit performance against enterprise considerations. Such long-established patterns of organizational behavior are tough to break. Fortunately, as RBC discovered, people can be trained to think and work

  10. Anisotropic Negative Thermal Expansion Behavior of the As-Fabricated Ti-Rich and Equiatomic Ti-Ni Alloys Induced by Preferential Grain Orientation

    Science.gov (United States)

    Zhao, Zhong-Xun; Ma, Xiao; Cao, Shan-Shan; Ke, Chang-Bo; Zhang, Xin-Ping

    2018-03-01

    The present study focuses on the anisotropic negative thermal expansion (NTE) behaviors of Ti-rich (Ti54Ni46) and equiatomic Ti-Ni (Ti50Ni50) alloys fabricated by vacuum arc melting and without subsequent plastic deformation. Both alloys exhibit NTE responses in vertical and horizontal directions, and the total strains and CTEs of the NTE stage along the two mutually perpendicular measuring directions are obviously different, indicating obvious anisotropic NTE behavior of the alloys. Besides, the numerical differences between the starting temperature of NTE and austenitic transformation and between the finishing temperature of NTE and austenitic transformation are very small, which indicates that an apparent relationship exists between the NTE behavior and the phase transformation. The microstructure in the vertical cross sections shows obviously preferential orientation characteristics: Ti2Ni phases of both alloys grow along the vertical direction, and B19' martensite of Ti50Ni50 alloy has distinct preferential orientation, which results from a large temperature gradient between the top and the bottom of the button ingots during solidification. The microstructure with preferential orientation induces the anisotropic NTE behavior of the samples.

  11. Which key properties controls the preferential transport in the vadose zone under transient hydrological conditions

    Science.gov (United States)

    Groh, J.; Vanderborght, J.; Puetz, T.; Gerke, H. H.; Rupp, H.; Wollschlaeger, U.; Stumpp, C.; Priesack, E.; Vereecken, H.

    2015-12-01

    Understanding water flow and solute transport in the unsaturated zone is of great importance for an appropriate land use management strategy. The quantification and prediction of water and solute fluxes through the vadose zone can help to improve management practices in order to limit potential risk on our fresh water resources. Water related solute transport and residence time is strongly affected by preferential flow paths in the soil. Water flow in soils depends on soil properties and site factors (climate or experiment conditions, land use) and are therefore important factors to understand preferential solute transport in the unsaturated zone. However our understanding and knowledge of which on-site properties or conditions define and enhance preferential flow and transport is still poor and mostly limited onto laboratory experimental conditions (small column length and steady state boundary conditions). Within the TERENO SOILCan lysimeter network, which was designed to study the effects of climate change on soil functions, a bromide tracer was applied on 62 lysimeter at eight different test sites between Dec. 2013 and Jan. 2014. The TERENO SOILCan infrastructure offers the unique possibility to study the occurrence of preferential flow and transport of various soil types under different natural transient hydrological conditions and land use (crop, bare and grassland) at eight TERENO SOILCan observatories. Working with lysimeter replicates at each observatory allows defining the spatial variability of preferential transport and flow. Additionally lysimeters in the network were transferred within and between observatories in order to subject them to different rainfall and temperature regimes and enable us to relate the soil type susceptibility of preferential flow and transport not only to site specific physical and land use properties, but also to different transient boundary conditions. Comparison and statistical analysis between preferential flow indicators 5

  12. TWO MEASURES OF THE DEPENDENCE OF PREFERENTIAL RANKINGS ON CATEGORICAL VARIABLES

    Directory of Open Access Journals (Sweden)

    Lissowski Grzegorz

    2017-06-01

    Full Text Available The aim of this paper is to apply a general methodology for constructing statistical methods, which is based on decision theory, to give a statistical description of preferential rankings, with a focus on the rankings’ dependence on categorical variables. In the paper, I use functions of description errors that are based on the Kemeny and Hamming distances between preferential orderings, but the proposed methodology can also be applied to other methods of estimating description errors.

  13. Growing hairs in shorn cattle

    Directory of Open Access Journals (Sweden)

    Cecília José Veríssimo

    2013-12-01

    Full Text Available The shearing operation can provide double benefits to the cattle: they can become more heat tolerant and the tick infestation decreases. The cattle tick Rhipicephalus (Boophilus microplus causes great losses to dairy cattle, especially to the Holstein cattle because they are very susceptible to this tick. Its control is becoming each day more difficult, owing to the increasing resistance to acaricides they are acquiring. The objective of this work was to study the growing of haircoat following shearing. We made our experiment with 17 animals, 7 females and 10 males. They were shaved on the anterior third (head, neck, dewlap, scapula and arm of one side, at random. The work was performed in two steps: they were shorn for the first time on August 2nd 2012, with a size 10 blade in a clipper Oster model GoldenA5, which left the fur coat 2 mm long. Then we evaluated the hair length growing by collecting fortnightly three sample of hairs in the middle of the scapula, with  electric pliers, modified for this purpose, in both sides of the animals, sheared and non-sheared, until 30 days after this shearing. The three hair samples were put inside a little plastic bag per animal. Meanwhile, as we thought that the animals shearing had to be done closer to the skin, we decided to shear them again (in the same side shorn before, on October 2nd 2012. We changed our procedure using the same machine, but now with a blade size 30, which left the fur coat 1mm thick. After that, we collected again, fortnightly, samples of hairs on both sides during 2 months. The 10 longest hairs in the plastig bag were measured using a graph paper and the average per animal was calculated in each data and blade. A random design was applied for statistical analysis, the hair length of both sides, sheared and non sheared were compared by a two related samples tests – Wilcoxon, in a non parametric test, using the SPSSP 12.0 program, in each data within each blade. Using blade size

  14. Case grows for climate change

    Energy Technology Data Exchange (ETDEWEB)

    Hileman, B.

    1999-08-09

    In the four years since the IPCC stated that 'the balance of evidence suggests a discernible human influence on global climate', evidence for anomalous warming has become more compelling, and as a result scientists have become more concerned that human-induced climate change has already arrived. The article summarises recent extra evidence on global temperatures, carbon dioxide measurements, ice shelf breakup, coral bleaching, unstable climates and improved climate models. At the time of the Kyoto conference, the US became keen on the idea that enhancing forest and soil carbon sequestration was a good way to offset emissions reduction targets. Congress is however under the opinion on that the Kyoto protocol presents a threat to the US economy, and senate is very unlikely to ratify the protocol during the Clinton Administration. The debate as to whether the US government should mandate major emission reduction or wait for more scientific certainty may continue for a number of years, but, growing concern of scientists and the public for the harmful effects of climate change may cause a change. 4 figs., 8 photos.

  15. Protein nutrition of growing cattle

    International Nuclear Information System (INIS)

    Chalupa, W.; Scott, G.C.

    1976-01-01

    In vitro studies on apparent degradation of amino acids by mixed and pure cultures of rumen bacteria demonstrated that (a) amino acids are degraded at differing rates (Arg, Thr>Lys, Phe, Leu, Ile>Val, Met); (b) certain amino acids (Met, Val, Try, Orn) are degraded to greater extents when fermented alone than in conjunction with other amino acids; (c) individual strains of rumen bacteria do not utilize all amino acids; and (d) total ruminal degradation of amino acids is the result of extensive bacterial interaction, and may vary greatly depending on the predominant types of micro-organisms present. Abomasal infusion of a mixture of 10 essential amino acids consistently increased nitrogen retention, but attempts to elucidate primary limiting amino acids were not conclusive. Our data suggested that supplementary methionine alone may not significantly increase nitrogen retention, but methionine must be present in order to obtain responses from other amino acids. Methionine plus lysine plus threonine usually increased nitrogen retention, but the magnitude of responses varied. The classical nitrogen balance technique may lack the sensitivity needed to detect small responses resulting from supplements of single amino acids, or growing cattle, unlike sheep used for wool growth, may not be suffering from specific amino acid deficiencies. Chemical suppression of ruminal degradation of amino acids produced significant increases in nitrogen retention and growth, and improved feed efficiencies. Productivity responses to rumen bypass techniques would seem to depend primarily upon (a) the degree to which dietary protein is degraded in the rumen, and (b) the quantity of absorbable amino acids supplied by the diet in relation to quantities required by the animal. (author)

  16. Growing population causes of unemployment.

    Science.gov (United States)

    1995-01-01

    At the March, 1995, International Meeting on Population and Social Development in Copenhagen, during the session on unemployment, underemployment, and population it was stated that the problem of employment was the extent to which a nation's labor supply was not matched by labor demand or job opportunities. Population was thus a supply factor, and the country's economic situation was a demand factor. The demographic variables that were considered important in the supply of labor were: a) the size and rate of growth of the population, which was a function of the birth rate, the death rate, and migration; and b) the age structure of the population, which was also a product of the rate of growth of the population and its distribution. An imbalance between the supply of labor and the demand for it gave rise to unemployment and underemployment. The vicious cycle generated by a high dependency burden associated with a young age-structure led to low savings and investments, which in turn led to low economic growth and a low standard of living. This produced high fertility rates, which in turn heightened the dependency burden perpetuating the cycle. This vicious cycle could be broken at only two points: at the high fertility stage, primarily by introducing family planning programs; and at the stage of low economic growth, by adopting policies to accelerate economic growth. To be successful, however, both actions had to be pursued simultaneously. Numerous participants emphasized the global nature of the issue of unemployment and underemployment; the effects of international competition and restrictive trade policies on employment opportunities. The growing disparity between North and South had created a social injustice between countries. Several participants called for more humane policies that favored democracy and promoted human development, and asked for assistance to help create an enabling environment for social and economic development.

  17. How Your Fetus Grows During Pregnancy

    Science.gov (United States)

    ... Patients About ACOG How Your Fetus Grows During Pregnancy Home For Patients Search FAQs How Your Fetus ... 2018 PDF Format How Your Fetus Grows During Pregnancy Pregnancy How does pregnancy begin? What is the ...

  18. Menopausal women's positive experience of growing older

    DEFF Research Database (Denmark)

    Hvas, Lotte

    2006-01-01

    This paper aims to describe menopausal women's positive experience of growing older and becoming middle-aged.......This paper aims to describe menopausal women's positive experience of growing older and becoming middle-aged....

  19. Transcriptome-wide identification of preferentially expressed genes in the hypothalamus and pituitary gland.

    Science.gov (United States)

    St-Amand, Jonny; Yoshioka, Mayumi; Tanaka, Keitaro; Nishida, Yuichiro

    2011-01-01

    To identify preferentially expressed genes in the central endocrine organs of the hypothalamus and pituitary gland, we generated transcriptome-wide mRNA profiles of the hypothalamus, pituitary gland, and parietal cortex in male mice (12-15 weeks old) using serial analysis of gene expression (SAGE). Total counts of SAGE tags for the hypothalamus, pituitary gland, and parietal cortex were 165824, 126688, and 161045 tags, respectively. This represented 59244, 45151, and 55131 distinct tags, respectively. Comparison of these mRNA profiles revealed that 22 mRNA species, including three potential novel transcripts, were preferentially expressed in the hypothalamus. In addition to well-known hypothalamic transcripts, such as hypocretin, several genes involved in hormone function, intracellular transduction, metabolism, protein transport, steroidogenesis, extracellular matrix, and brain disease were identified as preferentially expressed hypothalamic transcripts. In the pituitary gland, 106 mRNA species, including 60 potential novel transcripts, were preferentially expressed. In addition to well-known pituitary genes, such as growth hormone and thyroid stimulating hormone beta, a number of genes classified to function in transport, amino acid metabolism, intracellular transduction, cell adhesion, disulfide bond formation, stress response, transcription, protein synthesis, and turnover, cell differentiation, the cell cycle, and in the cytoskeleton and extracellular matrix were also preferentially expressed. In conclusion, the current study identified not only well-known hypothalamic and pituitary transcripts but also a number of new candidates likely to be involved in endocrine homeostatic systems regulated by the hypothalamus and pituitary gland.

  20. Transcriptome-wide identification of preferentially expressed genes in the hypothalamus and pituitary gland

    Directory of Open Access Journals (Sweden)

    Jonny eSt-Amand

    2012-01-01

    Full Text Available To identify preferentially expressed genes in the central endocrine organs of the hypothalamus and pituitary gland, we generated transcriptome-wide mRNA profiles of the mouse hypothalamus, pituitary gland and parietal cortex using serial analysis of gene expression (SAGE. Total counts of SAGE tags for the hypothalamus, pituitary gland and parietal cortex were 165824, 126688 and 161045 tags, respectively. This represented 59244, 45151 and 55131 distinct tags, respectively. Comparison of these mRNA profiles revealed that 22 mRNA species, including three potential novel transcripts, were preferentially expressed in the hypothalamus. In addition to well-known hypothalamic transcripts, such as hypocretin, several genes involved in hormone function, intracellular transduction, metabolism, protein transport, steroidogenesis, extracellular matrix and brain disease were identified as preferentially expressed hypothalamic transcripts. In the pituitary gland, 106 mRNA species, including 60 potential novel transcripts, were preferentially expressed. In addition to well-known pituitary genes, such as growth hormone and thyroid stimulating hormone beta, a number of genes classified to function in transport, amino acid metabolism, intracellular transduction, cell adhesion, disulfide bond formation, stress response, transcription, protein synthesis and turnover, cell differentiation, the cell cycle and in the cytoskeleton and extracellular matrix were also preferentially expressed. In conclusion, the current study identified not only well-known hypothalamic and pituitary transcripts but also a number of new candidates likely to be involved in endocrine homeostatic systems regulated by the hypothalamus and pituitary gland.

  1. Nutritional studies on growing rabbits

    International Nuclear Information System (INIS)

    Hassan, A.M.E.A.M.

    2013-01-01

    This work was carried out to study the effect of adding drinking water with either, copper sulfate, ascorbic acid or drinking cooled water on growth performance (live body weight,body weight gain, feed intake, feed conversion and water consumption), digestibility coefficients of nutrients, carcass traits, some physiological parameters and economical efficiency of growing NZW rabbits under Egyptian summer conditions. Ninety six weanling New Zealand White (NZW) male rabbits at five weeks of age and nearly similar average body weight (650.3 ±3.7 g) were randomly divided into eight treatment groups (twelve rabbits in each group), and then each group was subdivided into four replicates, each of three rabbits. The rabbits were assigned to drinking water as follow: the 1 st group was given fresh tap water without any additives as a control. The 2 n d, 3 r d and 4 t h groups were given tap fresh water supplemented with copper sulfate at levels of 40, 80 and 120 mg/L drinking water, respectively. The 5 t h, 6 t h and 7 t h groups were given tap fresh water supplemented with ascorbic acid at levels of 250, 500 and 750 mg/L drinking water, respectively. The 8 t h group was given cooled drinking water (CW) at 10-15 degree C. Results showed that supplementation of 40 or 80 mg copper sulfate/L or 500 mg ascorbic acid/L to heat-stressed rabbits drinking water improved final live body weight, body weight gain, daily water consumption, feed conversion ratio, performance index and economical efficiency. Hot carcass percentage was significantly (P<0.01) decreased with 80 mg/L copper sulfate and increased significantly (P<0.01) due to supplementation the drinking water with 250 mg ascorbic acid/L. Cooled water (10-15 degree C) improved significantly (P<0.01) each of final body weight, body weight gain, feed conversion ratio, performance index, economical efficiency and decreased significantly (P<0.01) each of hot carcass %, dressed weight %, heart %, total giblets %, rectal

  2. Preferential flow in the vadose zone and interface dynamics: Impact of microbial exudates

    Science.gov (United States)

    Li, Biting; Pales, Ashley R.; Clifford, Heather M.; Kupis, Shyla; Hennessy, Sarah; Liang, Wei-Zhen; Moysey, Stephen; Powell, Brian; Finneran, Kevin T.; Darnault, Christophe J. G.

    2018-03-01

    In the hydrological cycle, the infiltration process is a critical component in the distribution of water into the soil and in the groundwater system. The nonlinear dynamics of the soil infiltration process yield preferential flow which affects the water distribution in soil. Preferential flow is influenced by the interactions between water, soil, plants, and microorganisms. Although the relationship among the plant roots, their rhizodeposits and water transport in soil has been the subject of extensive study, the effect of microbial exudates has been studied in only a few cases. Here the authors investigated the influence of two artificial microbial exudates-catechol and riboflavin-on the infiltration process, particularly unstable fingered flow, one form of preferential flow. Flow experiments investigating the effects of types and concentrations of microbial exudates on unstable fingered flow were conducted in a two-dimensional tank that was filled with ASTM

  3. How Medical Tourism Enables Preferential Access to Care: Four Patterns from the Canadian Context.

    Science.gov (United States)

    Snyder, Jeremy; Johnston, Rory; Crooks, Valorie A; Morgan, Jeff; Adams, Krystyna

    2017-06-01

    Medical tourism is the practice of traveling across international borders with the intention of accessing medical care, paid for out-of-pocket. This practice has implications for preferential access to medical care for Canadians both through inbound and outbound medical tourism. In this paper, we identify four patterns of medical tourism with implications for preferential access to care by Canadians: (1) Inbound medical tourism to Canada's public hospitals; (2) Inbound medical tourism to a First Nations reserve; (3) Canadian patients opting to go abroad for medical tourism; and (4) Canadian patients traveling abroad with a Canadian surgeon. These patterns of medical tourism affect preferential access to health care by Canadians by circumventing domestic regulation of care, creating jurisdictional tensions over the provision of health care, and undermining solidarity with the Canadian health system.

  4. Kinds and meaning of preferential credits for development of agriculture and rural areas

    Directory of Open Access Journals (Sweden)

    Antoni Mickiewicz

    2013-06-01

    Full Text Available The theme of the paper was of preferential credits granted in two periods, that means after Poland’s accession to the European Union (2004-2006 and in the period after introduction of new legal regulations (2007-2010. The institution responsible for realisation of preferential credits was Agency of Restructuring and Modernisation of Agriculture which delegated its rights to banks. The credit policy in first period of our functioning in the European Union relied on gradual ending old legal regulations, not compliant with EU standards and undertaking activities in adaptation of Polish agriculture to standards obeyed in EU-15 Member States. Directions of preferential credits granting were changed in 2007. There were introduced 7 credit lines which aim was improvement of production efficiency, better use of production base in agricultural farms and acceleration of agrarian changes. The biggest beneficiaries of structural pensions were young farmers and farmers who wanted to increase the size of their farms.

  5. Inert Carbon Nanoparticles for the Assessment of Preferential Flow in Saturated Dual-Permeability Porous Media

    KAUST Repository

    Yao, Chuanjin

    2017-06-07

    Knowledge of preferential flow in heterogeneous environments is essential for enhanced hydrocarbon recovery, geothermal energy extraction, and successful sequestration of chemical waste and carbon dioxide. Dual tracer tests using nanoparticles with a chemical tracer could indicate the preferential flow. A dual-permeability model with a high permeable core channel surrounded by a low permeable annulus was constructed and used to determine the viability of an inert carbon nanoparticle tracer for this application. A series of column experiments were conducted to demonstrate how this nanoparticle tracer can be used to implement the dual tracer tests in heterogeneous environments. The results indicate that, with the injection rate selected and controlled appropriately, nanoparticles together with a chemical tracer can assess the preferential flow in heterogeneous environments. The results also implement the dual tracer tests in heterogeneous environments by simultaneously injecting chemical and nanoparticle tracers.

  6. When and where does preferential flow matter - from observation to large scale modelling

    Science.gov (United States)

    Weiler, Markus; Leistert, Hannes; Steinbrich, Andreas

    2017-04-01

    Preferential flow can be of relevance in a wide range of soils and the interaction of different processes and factors are still difficult to assess. As most studies (including our own studies) focusing on the effect of preferential flow are based on relatively high precipitation rates, there is always the question how relevant preferential flow is under natural conditions, considering the site specific precipitation characteristics, the effect of the drying and wetting cycle on the initial soil water condition and shrinkage cracks, the site specific soil properties, soil structure and rock fragments, and the effect of plant roots and soil fauna (e.g. earthworm channels). In order to assess this question, we developed the distributed, process-based model RoGeR (Runoff Generation Research) to include a large number relevant features and processes of preferential flow in soils. The model was developed from a large number of process based research and experiments and includes preferential flow in roots, earthworm channels, along rock fragments and shrinkage cracks. We parameterized the uncalibrated model at a high spatial resolution of 5x5m for the whole state of Baden-Württemberg in Germany using LiDAR data, degree of sealing, landuse, soil properties and geology. As the model is an event based model, we derived typical event based precipitation characteristics based on rainfall duration, mean intensity and amount. Using the site-specific variability of initial soil moisture derived from a water balance model based on the same dataset, we simulated the infiltration and recharge amounts of all event classes derived from the event precipitation characteristics and initial soil moisture conditions. The analysis of the simulation results allowed us to extracts the relevance of preferential flow for infiltration and recharge considering all factors above. We could clearly see a strong effect of the soil properties and land-use, but also, particular for clay rich soils a

  7. Introduction to the Special Issue: Precarious Solidarity-Preferential Access in Canadian Health Care.

    Science.gov (United States)

    Reid, Lynette

    2017-06-01

    Systems of universal health coverage may aspire to provide care based on need and not ability to pay; the complexities of this aspiration (conceptual, practical, and ethical) call for normative analysis. This special issue arises in the wake of a judicial inquiry into preferential access in the Canadian province of Alberta, the Vertes Commission. I describe this inquiry and set out a taxonomy of forms of differential and preferential access. Papers in this special issue focus on the conceptual specification of health system boundaries (the concept of medical need) and on the normative questions raised by complex models of funding and delivery of care, where patients, providers, and services cross system boundaries.

  8. Preferential Solvation of Silver (I) Bromate in Methanol-Dimethylsulfoxide Mixtures

    Science.gov (United States)

    Janardhanan, S.; Kalidas, C.

    1984-06-01

    The solubiltiy of silver bromate, the Gibbs transfer energy of Ag+ and BrO3- and the solvent transport number in methanol-dimethyl sulfoxide mixtures are reported. The solubility of silver bromate increases with addition of DMSO. The Gibbs energy of transfer of the silver ion (based on the ferrocene reference method) decreases, while that of the bromate ion becomes slightly negative with the addition of DMSO. The solvent transport number A passes through a maximum (⊿ = 1.0 at XDMSO = 0.65. From these results, it is concluded that the silver ion is preferentially solvated by DMSO whereas the bromate ion shows no preferential solvation.

  9. Consequences of preferential flow in cracking clay soils for contamination-risk of shallow aquifers

    NARCIS (Netherlands)

    Oostindie, K.; Bronswijk, J.J.B.

    1995-01-01

    A method is presented to asses the contamination risk of aquifers covered with cracking clay soils, with special emphasis on preferential flow through shrinkage cracks. A water extraction area was divided into units with homogeneous soil types and hydrological conditions. For each unit, a

  10. Study of a diffusion flamelet model, with preferential diffusion effects included

    NARCIS (Netherlands)

    Delhaye, S.; Somers, L.M.T.; Bongers, H.; Oijen, van J.A.; Goey, de L.P.H.; Dias, V.

    2005-01-01

    The non-premixed flamelet model of Peters [1] (model1), which does not include preferential diffusion effects is investigated. Two similar models are presented, but without the assumption of unity Lewis numbers. One of these models was derived by Peters & Pitsch [2] (model2), while the other one was

  11. Preferential selection based on degree difference in the spatial prisoner's dilemma games

    Science.gov (United States)

    Huang, Changwei; Dai, Qionglin; Cheng, Hongyan; Li, Haihong

    2017-10-01

    Strategy evolution in spatial evolutionary games is generally implemented through imitation processes between individuals. In most previous studies, it is assumed that individuals pick up one of their neighbors randomly to learn from. However, by considering the heterogeneity of individuals' influence in the real society, preferential selection is more realistic. Here, we introduce a preferential selection mechanism based on degree difference into spatial prisoner's dilemma games on Erdös-Rényi networks and Barabási-Albert scale-free networks and investigate the effects of the preferential selection on cooperation. The results show that, when the individuals prefer to choose the neighbors who have small degree difference with themselves to imitate, cooperation is hurt by the preferential selection. In contrast, when the individuals prefer to choose those large degree difference neighbors to learn from, there exists optimal preference strength resulting in the maximal cooperation level no matter what the network structure is. In addition, we investigate the robustness of the results against variations of the noise, the average degree and the size of network in the model, and find that the qualitative features of the results are unchanged.

  12. Identification of Homophily and Preferential Recruitment in Respondent-Driven Sampling.

    Science.gov (United States)

    Crawford, Forrest W; Aronow, Peter M; Zeng, Li; Li, Jianghong

    2018-01-01

    Respondent-driven sampling (RDS) is a link-tracing procedure used in epidemiologic research on hidden or hard-to-reach populations in which subjects recruit others via their social networks. Estimates from RDS studies may have poor statistical properties due to statistical dependence in sampled subjects' traits. Two distinct mechanisms account for dependence in an RDS study: homophily, the tendency for individuals to share social ties with others exhibiting similar characteristics, and preferential recruitment, in which recruiters do not recruit uniformly at random from their network alters. The different effects of network homophily and preferential recruitment in RDS studies have been a source of confusion and controversy in methodological and empirical research in epidemiology. In this work, we gave formal definitions of homophily and preferential recruitment and showed that neither is identified in typical RDS studies. We derived nonparametric identification regions for homophily and preferential recruitment and showed that these parameters were not identified unless the network took a degenerate form. The results indicated that claims of homophily or recruitment bias measured from empirical RDS studies may not be credible. We applied our identification results to a study involving both a network census and RDS on a population of injection drug users in Hartford, Connecticut (2012-2013). © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Preferential aerosolization of bacteria in bioaerosols generated in vitro.

    Science.gov (United States)

    Perrott, P; Turgeon, N; Gauthier-Levesque, L; Duchaine, C

    2017-09-01

    Little is known about how bacteria are aerosolized in terms of whether some bacteria will be found in the air more readily than others that are present in the source. This report describes in vitro experiments to compare aerosolization rates (also known as preferential aerosolization) of Gram-positive and Gram-negative bacteria as well as rod- and coccus-shaped bacteria, using two nebulization conditions. A consortium of five bacterial species was aerosolized in a homemade chamber. Aerosols generated with a commercial nebulizer and a homemade bubble-burst aerosol generator were compared. Data suggest that Pseudomonas aeruginosa was preferentially aerosolized in comparison to Moraxella catarrhalis, Lactobacillus paracasei, Staphylococcus aureus and Streptococcus suis, independently of the method of aerosolization. Bacterial integrity of Strep. suis was more preserved compared to other bacteria studied as revealed with PMA-qPCR. We reported the design of an aerosol chamber and bubble-burst generator for the in vitro study of preferential aerosolization. In our setting, preferential aerosolization was influenced by bacterial properties instead of aerosolization mechanism. These findings could have important implications for predicting the composition of bioaerosols in various locations such as wastewater treatment plants, agricultural settings and health care settings. © 2017 The Society for Applied Microbiology.

  14. Using Dye Tracer for Visualization of Preferential Flow at Macro- and Microscales

    Czech Academy of Sciences Publication Activity Database

    Kodešová, R.; Němeček, K.; Kodeš, V.; Žigová, Anna

    2012-01-01

    Roč. 11, č. 1 (2012), s. 287-295 ISSN 1539-1663 R&D Projects: GA ČR GA526/08/0434 Institutional research plan: CEZ:AV0Z30130516 Keywords : dye tracer * preferential flow * soil types * macro- and microsccale Subject RIV: DF - Soil Science Impact factor: 2.200, year: 2012

  15. Effects of Soil Compaction and Organic Carbon Content on Preferential Flow in Loamy Field Soils

    DEFF Research Database (Denmark)

    Soares, Antonio; Moldrup, Per; Vendelboe, Anders Lindblad

    2015-01-01

    Preferential flow and transport through macropores affects plant water use efficiency and enhances leaching of agrochemicals and the transport of colloids, thereby increasing the risk for contamination of groundwater resources. As part of the Danish Pesticide Leaching Assessment Program this study...

  16. Emergency abdominal aortic aneurysm repair with a preferential endovascular strategy : Mortality and cost-effectiveness analysis

    NARCIS (Netherlands)

    Kapma, Marten R.; Groen, Henk; Oranen, Bjorn I.; van der Hilst, Christian S.; Tielliu, Ignace F.; Zeebregts, Clark J.; Prins, Ted R.; van den Dungen, Jan J.; Verhoeven, Eric L.

    2007-01-01

    Purpose: To assess mortality and treatment costs of a new management protocol with preferential use of emergency endovascular aneurysm repair (eEVAR) for acute abdominal aortic aneurysm (AAA). Methods: From September 2003 until February 2005, 49 consecutive patients (45 men; mean age 71 years) with

  17. Preferential semantics for action specification in first-order modal action logic

    NARCIS (Netherlands)

    Broersen, Jan; Wieringa, Roelf J.

    In this paper we investigate preferential semantics for declarative specifications in a First Order Modal Action Logic. We address some well known problems: the frame problem, the qualification problem and the ramification problem. We incorporate the assumptions that are inherent to both the frame

  18. Using the dye tracer for visualization of preferential flow in macro and micro-scale

    Czech Academy of Sciences Publication Activity Database

    Kodešová, R.; Němeček, K.; Kodeš, V.; Fér, M.; Jirků, V.; Nikodem, A.; Žigová, Anna; Jakšík, O.; Kočárek, M.

    2010-01-01

    Roč. 12, - (2010) ISSN 1029-7006. [European Geosciences Union General Assembly 2010. 02.05.2010-07.05.2010, Wienna] R&D Projects: GA ČR GA526/08/0434 Institutional research plan: CEZ:AV0Z30130516 Keywords : dye tracer * preferential flow * micromorphology Subject RIV: DF - Soil Science

  19. Evidence for preferential flux flow at the grain boundaries of superconducting RF-quality niobium

    Science.gov (United States)

    Sung, Z.-H.; Lee, P. J.; Gurevich, A.; Larbalestier, D. C.

    2018-04-01

    The question of whether grain boundaries (GBs) in niobium can be responsible for lowered operating field (B RF) or quality factor (Q 0) in superconducting radio frequency (SRF) cavities is still controversial. Here, we show by direct DC transport across planar GBs isolated from a slice of very large-grain SRF-quality Nb that vortices can preferentially flow along the grain boundary when the external magnetic field lies in the GB plane. However, increasing the misalignment between the GB plane and the external magnetic field vector markedly reduces preferential flux flow along the GB. Importantly, we find that preferential GB flux flow is more prominent for a buffered chemical polished than for an electropolished bi-crystal. The voltage-current characteristics of GBs are similar to those seen in low angle grain boundaries of high temperature superconductors where there is clear evidence of suppression of the superconducting order parameter at the GB. While local weakening of superconductivity at GBs in cuprates and pnictides is intrinsic, deterioration of current transparency of GBs in Nb appears to be extrinsic, since the polishing method clearly affect the local GB degradation. The dependence of preferential GB flux flow on important cavity preparation and experimental variables, particularly the final chemical treatment and the angle between the magnetic field and the GB plane, suggests two more reasons why real cavity performance can be so variable.

  20. Winning the competition for supplier resources: The role of preferential resource allocation from suppliers

    NARCIS (Netherlands)

    Pulles, Niels Jaring; Veldman, Jasper; Schiele, Holger

    2016-01-01

    Purpose This paper examines the competition between buying firms for the supplier’s competitive resources. The purpose of this paper is to examine how indirect capabilities – the ability to access external resources – can help in obtaining preferential resource allocation from suppliers.

  1. 19 CFR 10.233 - Articles eligible for preferential tariff treatment.

    Science.gov (United States)

    2010-04-01

    ... control of the customs authority of the intermediate country; (ii) Did not enter into the commerce of the... 19 Customs Duties 1 2010-04-01 2010-04-01 false Articles eligible for preferential tariff treatment. 10.233 Section 10.233 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND...

  2. The dynamics of power laws : fitness and aging in preferential attachment trees

    NARCIS (Netherlands)

    Garavaglia, A.; van der Hofstad, R.W.; Woeginger, G.

    2017-01-01

    Continuous-time branching processes describe the evolution of a population whose individuals generate a random number of children according to a birth process. Such branching processes can be used to understand preferential attachment models in which the birth rates are linear functions. We are

  3. Hypoxia preferentially destroys GABAergic neurons in developing rat neocortex explants in culture

    NARCIS (Netherlands)

    Romijn, H. J.; Ruijter, J. M.; Wolters, P. S.

    1988-01-01

    The hypothesis that hypoxic ischemia before or during the human birth process preferentially destroys GABAergic nerve cells, particularly in the neocortex, was tested in a tissue culture model system. To that end, rat neocortex explants dissected from 6-day-old rat pups and cultured to a

  4. Common mycorrhizal networks amplify competition by preferential mineral nutrient allocation to large host plants.

    Science.gov (United States)

    Weremijewicz, Joanna; Sternberg, Leonel da Silveira Lobo O'Reilly; Janos, David P

    2016-10-01

    Arbuscular mycorrhizal (AM) fungi interconnect plants in common mycorrhizal networks (CMNs) which can amplify competition among neighbors. Amplified competition might result from the fungi supplying mineral nutrients preferentially to hosts that abundantly provide fixed carbon, as suggested by research with organ-cultured roots. We examined whether CMNs supplied (15) N preferentially to large, nonshaded, whole plants. We conducted an intraspecific target-neighbor pot experiment with Andropogon gerardii and several AM fungi in intact, severed or prevented CMNs. Neighbors were supplied (15) N, and half of the target plants were shaded. Intact CMNs increased target dry weight (DW), intensified competition and increased size inequality. Shading decreased target weight, but shaded plants in intact CMNs had mycorrhizal colonization similar to that of sunlit plants. AM fungi in intact CMNs acquired (15) N from the substrate of neighbors and preferentially allocated it to sunlit, large, target plants. Sunlit, intact CMN, target plants acquired as much as 27% of their nitrogen from the vicinity of their neighbors, but shaded targets did not. These results suggest that AM fungi in CMNs preferentially provide mineral nutrients to those conspecific host individuals best able to provide them with fixed carbon or representing the strongest sinks, thereby potentially amplifying asymmetric competition below ground. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  5. Surface morphology and preferential orientation growth of TaC crystals formed by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xiong Xiang, E-mail: Xiong228@sina.co [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China); Chen Zhaoke; Huang Baiyun; Li Guodong [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China); Zheng Feng [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Xiao Peng; Zhang Hongbo [State Key Lab for Powder Metallurgy, Central South University, Changsha 410083 (China)

    2009-04-02

    TaC film was deposited on (002) graphite sheet by isothermal chemical vapor deposition using TaCl{sub 5}-Ar-C{sub 3}H{sub 6} mixtures, with deposition temperature 1200 {sup o}C and pressure about 200 Pa. The influence of deposition position (or deposition rate) on preferential orientation and surface morphology of TaC crystals were investigated by X-ray diffraction and scanning electron microscopy methods. The deposits are TaC plus trace of C. The crystals are large individual columns with pyramidal-shape at deposition rate of 32.4-37.3 {mu}m/h, complex columnar at 37.3-45.6 {mu}m/h, lenticular-like at 45.6-54.6 {mu}m/h and cauliflower-like at 54.6-77.3 {mu}m/h, with <001>, near <001>, <110> and no clear preferential orientation, respectively. These results agree in part with the preditions of the Pangarov's model of the relationship between deposition rate and preferential growth orientation. The growth mechanism of TaC crystals in <001>, near <001>, <111> and no clear preferential orientation can be fairly explained by the growth parameter {alpha} with Van der Drift's model, deterioration model and Meakin model. Furthermore, a nucleation and coalescence model is also proposed to explain the formation mechanism of <110> lenticular-like crystals.

  6. Exploring the antecedents of preferential customer treatment by suppliers: a mixed methods approach

    NARCIS (Netherlands)

    Huttinger, Lisa; Schiele, Holger; Schröer, Dennis

    2014-01-01

    Purpose – This paper aims to understand the factors that influence a supplier’s choice to treat selected customers more preferentially than others. Suppliers often lack the resources to treat all their customers equally, instead having to make choices to treat some customers as preferred. Empirical

  7. Inhibition of a Putative Dihydropyrimidinase from Pseudomonas aeruginosa PAO1 by Flavonoids and Substrates of Cyclic Amidohydrolases.

    Directory of Open Access Journals (Sweden)

    Cheng-Yang Huang

    Full Text Available Dihydropyrimidinase is a member of the cyclic amidohydrolase family, which also includes allantoinase, dihydroorotase, hydantoinase, and imidase. These metalloenzymes possess very similar active sites and may use a similar mechanism for catalysis. However, whether the substrates and inhibitors of other cyclic amidohydrolases can inhibit dihydropyrimidinase remains unclear. This study investigated the inhibition of dihydropyrimidinase by flavonoids and substrates of other cyclic amidohydrolases. Allantoin, dihydroorotate, 5-hydantoin acetic acid, acetohydroxamate, orotic acid, and 3-amino-1,2,4-triazole could slightly inhibit dihydropyrimidinase, and the IC50 values of these compounds were within the millimolar range. The inhibition of dihydropyrimidinase by flavonoids, such as myricetin, quercetin, kaempferol, galangin, dihydromyricetin, and myricitrin, was also investigated. Some of these compounds are known as inhibitors of allantoinase and dihydroorotase. Although the inhibitory effects of these flavonoids on dihydropyrimidinase were substrate-dependent, dihydromyricetin significantly inhibited dihydropyrimidinase with IC50 values of 48 and 40 μM for the substrates dihydrouracil and 5-propyl-hydantoin, respectively. The results from the Lineweaver-Burk plot indicated that dihydromyricetin was a competitive inhibitor. Results from fluorescence quenching analysis indicated that dihydromyricetin could form a stable complex with dihydropyrimidinase with the K(d value of 22.6 μM. A structural study using PatchDock showed that dihydromyricetin was docked in the active site pocket of dihydropyrimidinase, which was consistent with the findings from kinetic and fluorescence studies. This study was the first to demonstrate that naturally occurring product dihydromyricetin inhibited dihydropyrimidinase, even more than the substrate analogs (>3 orders of magnitude. These flavonols, particularly myricetin, may serve as drug leads and dirty drugs (for multiple targets for designing compounds that target several cyclic amidohydrolases.

  8. The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1

    OpenAIRE

    Yee Meng Chong; Kah Yan How; Wai Fong Yin; Kok Gan Chan

    2018-01-01

    The quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation ...

  9. High-resolution visualization of Pseudomonas aeruginosa PAO1 biofilms by freeze-substitution transmission electron microscopy.

    Science.gov (United States)

    Hunter, Ryan C; Beveridge, Terry J

    2005-11-01

    High-pressure freeze-substitution and transmission electron microscopy have been used for high-resolution imaging of the natural structure of a gram-negative biofilm. Unlike more conventional embedding techniques, this method confirms many of the observations seen by confocal microscopy but with finer structural detail. It further reveals that there is a structural complexity to biofilms at both the cellular and extracellular matrix levels that has not been seen before. Different domains of healthy and lysed cells exist randomly dispersed within a single biofilm as well as different structural organizations of exopolymers. Particulate matter is suspended within this network of fibers and appears to be an integral part of the exopolymeric substance (EPS). O-side chains extending from the outer membrane are integrated into EPS polymers so as to form a continuum. Together, the results support the concept of physical microenvironments within biofilms and show a complexity that was hitherto unknown.

  10. MOLECULAR GENE CLONING OF NICOTINE-DEHIDROGENASE FROM THE pAO1 MEGAPLASMID OF ARTHROBACTER NICOTINOVORANS

    Directory of Open Access Journals (Sweden)

    Andreea Andrei

    2013-10-01

    Full Text Available 6-hydroxi-L-nicotine (6HNic has an important potential as a drug for neuro-degenerative disorders and a  suitable simple and reliable method for obtaining contaminant-free 6HNic preparations is required. Here, we envision the in-vitro production of 6HNic by using purified nicotine-dehydrogenase (NDH followed by HPLC or capillary electrophoresis techniques and we focus on the isolation and cloning of the three genes coding the NDH enzyme.  A PCR protocol was established for easy amplification and the DNA fragment containing the ndhLSM genes was directionally cloned into the pART2 vector.

  11. The influence of preferential flow on pressure propagation and landslide triggering of the Rocca Pitigliana landslide

    Science.gov (United States)

    Shao, Wei; Bogaard, Thom; Bakker, Mark; Berti, Matteo

    2016-12-01

    The fast pore water pressure response to rain events is an important triggering factor for slope instability. The fast pressure response may be caused by preferential flow that bypasses the soil matrix. Currently, most of the hydro-mechanical models simulate pore water pressure using a single-permeability model, which cannot quantify the effects of preferential flow on pressure propagation and landslide triggering. Previous studies showed that a model based on the linear-diffusion equation can simulate the fast pressure propagation in near-saturated landslides such as the Rocca Pitigliana landslide. In such a model, the diffusion coefficient depends on the degree of saturation, which makes it difficult to use the model for predictions. In this study, the influence of preferential flow on pressure propagation and slope stability is investigated with a 1D dual-permeability model coupled with an infinite-slope stability approach. The dual-permeability model uses two modified Darcy-Richards equations to simultaneously simulate the matrix flow and preferential flow in hillslopes. The simulated pressure head is used in an infinite-slope stability analysis to identify the influence of preferential flow on the fast pressure response and landslide triggering. The dual-permeability model simulates the height and arrival of the pressure peak reasonably well. Performance of the dual-permeability model is as good as or better than the linear-diffusion model even though the dual-permeability model is calibrated for two single pulse rain events only, while the linear-diffusion model is calibrated for each rain event separately. In conclusion, the 1D dual-permeability model is a promising tool for landslides under similar conditions.

  12. The fictional transition of the preferential orientation of yttria-stabilized zirconia thin films

    International Nuclear Information System (INIS)

    Lamas, J.S.; Leroy, W.P.; Depla, D.

    2012-01-01

    The fundamental study of the microstructural and textural evolution of yttria-stabilized zirconia (YSZ) thin films is of great importance given that the crystallographic properties are intimately related to their extrinsic or functional properties. In order to study these properties, YSZ thin films were obtained using dual magnetron sputtering. The results of a polar plot graph, based on X-ray diffraction (XRD) data, seem to indicate a transition from [200] out-of-plane preferential orientation to [111], indicating a dependence on composition and yttrium target–substrate (Y T–S) distance at low pressure. However, no transition is identified at high pressure, showing only [111] out-of-plane orientation, independent of composition and Y T–S distance. Scanning electron microscopy (SEM) indicates a tilt in the columnar structure of the film but no other microstructural change is in evidence, possibly related to the growth transition from [200] to [111]. Pole figures were used to clarify the texture transition in the YSZ thin films. These results indicate that there is indeed no transition in the preferential orientation of the films from [200] to [111] but a tilt of the [200] orientation towards the zirconium source. Detailed study using pole figures and SEM, clearly indicated that no growth zone transition was present and the effect is caused by geometrical configuration, contradicting expectations from standard θ/2θ XRD measurements. - Highlights: ► Study of the preferential orientation of Yttria-stabilized zirconia thin films ► Comparison of the preferential orientation at two different chamber pressures ► Correlation with the energy per adparticle and the extended structure zone model ► Use of pole figures analyses to clarify the change in the preferential orientation

  13. The fictional transition of the preferential orientation of yttria-stabilized zirconia thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lamas, J.S., E-mail: Jerika.Lamas@UGent.be; Leroy, W.P.; Depla, D.

    2012-12-15

    The fundamental study of the microstructural and textural evolution of yttria-stabilized zirconia (YSZ) thin films is of great importance given that the crystallographic properties are intimately related to their extrinsic or functional properties. In order to study these properties, YSZ thin films were obtained using dual magnetron sputtering. The results of a polar plot graph, based on X-ray diffraction (XRD) data, seem to indicate a transition from [200] out-of-plane preferential orientation to [111], indicating a dependence on composition and yttrium target-substrate (Y T-S) distance at low pressure. However, no transition is identified at high pressure, showing only [111] out-of-plane orientation, independent of composition and Y T-S distance. Scanning electron microscopy (SEM) indicates a tilt in the columnar structure of the film but no other microstructural change is in evidence, possibly related to the growth transition from [200] to [111]. Pole figures were used to clarify the texture transition in the YSZ thin films. These results indicate that there is indeed no transition in the preferential orientation of the films from [200] to [111] but a tilt of the [200] orientation towards the zirconium source. Detailed study using pole figures and SEM, clearly indicated that no growth zone transition was present and the effect is caused by geometrical configuration, contradicting expectations from standard {theta}/2{theta} XRD measurements. - Highlights: Black-Right-Pointing-Pointer Study of the preferential orientation of Yttria-stabilized zirconia thin films Black-Right-Pointing-Pointer Comparison of the preferential orientation at two different chamber pressures Black-Right-Pointing-Pointer Correlation with the energy per adparticle and the extended structure zone model Black-Right-Pointing-Pointer Use of pole figures analyses to clarify the change in the preferential orientation.

  14. Preferential transport of isoproturon at a plot scale and a field scale tile-drained site

    Science.gov (United States)

    Zehe, Erwin; Flühler, Hannes

    2001-06-01

    Irrigation experiments using the tracers Brilliant Blue (BB) and Bromide (Br) were conducted on three plots of 1.4×1.4 m 2 (plot scale) and a field scale subsurface drained test site (900 m 2) to clarify mechanisms causing rapid transport of surface applied Isoproturon (IPU) during preferential flow events. One of the small plots (site 10) and the field scale test site are located on the same field. One day after irrigation of the plot scale sites the Br and IPU concentration in two vertical soil profiles as well as the macroporousity on separate profiles and hydraulic properties of single macropores were determined. During irrigation of the field scale test site discharge, soil moisture as well as the concentration of IPU and Br in the drainage outlet were measured. Preferential flow in deep penetrating earthworm burrows caused a fast breakthrough of IPU and Br into the tile drain (1.2 m depth) at the field scale site as well as leaching of IPU into the subsoil (>0.8 m) at site 10. The results suggest a hierarchy of preconditions for the occurrence of preferential flow events of which a sufficient number of deep penetrating macropores interconnected to the soil surface seems to be the most important one. Moreover there is evidence that facilitated transport of IPU attached to mobile soil particles occurred during the preferential flow events at the field scale site and site 10. The susceptibility for preferential flow as well as the susceptibility for facilitated transport appear to be intrinsic properties of the investigated soil.

  15. Motility and Chemotaxis Mediate the Preferential Colonization of Gastric Injury Sites by Helicobacter pylori

    Science.gov (United States)

    Aihara, Eitaro; Closson, Chet; Matthis, Andrea L.; Schumacher, Michael A.; Engevik, Amy C.; Zavros, Yana; Ottemann, Karen M.; Montrose, Marshall H.

    2014-01-01

    Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases

  16. Response of growing bones to irradiation

    International Nuclear Information System (INIS)

    Gonzalez Gonzalez, D.

    1980-01-01

    This thesis describes the effects of ionizing radiations on growing bones. The epiphyseal disc of growing mouse tibia was selected as a model for the experiments. An attempt has been made to obtain clinical data from irradiated bones during the childhood and to quantitate this information. Within the range of possibilities correlations have been established between the experimental and clinical data. (Auth.)

  17. Combination of hypothiocyanite and lactoferrin (ALX-109) enhances the ability of tobramycin and aztreonam to eliminate Pseudomonas aeruginosa biofilms growing on cystic fibrosis airway epithelial cells.

    Science.gov (United States)

    Moreau-Marquis, Sophie; Coutermarsh, Bonita; Stanton, Bruce A

    2015-01-01

    Chelating iron may be a promising new therapy to eliminate Pseudomonas aeruginosa biofilms in the lungs of cystic fibrosis (CF) patients. Here, we investigate whether ALX-109 [a defined combination of an investigational drug containing lactoferrin (an iron-binding glycoprotein) and hypothiocyanite (a bactericidal agent)], alone and in combination with tobramycin or aztreonam, reduces P. aeruginosa biofilms grown on human CF airway epithelial cells. P. aeruginosa (PAO1 and six clinical isolates of Pseudomonas) biofilms grown at the apical surface of confluent monolayers of CF airway epithelial cells were treated with ALX-109, either alone or in combination with tobramycin or aztreonam. Bacterial cfu remaining after treatment were determined by plate counting. ALX-109 alone reduced PAO1 biofilm formation, but had no effect on established biofilms. ALX-109 enhanced the ability of tobramycin and aztreonam to inhibit PAO1 biofilm formation and to reduce established PAO1 biofilms. ALX-109 and tobramycin were additive in disrupting established biofilms formed by six clinical isolates of P. aeruginosa obtained from the sputum of CF patients. Mucoid P. aeruginosa isolates were most susceptible to the combination of ALX-109 and tobramycin. In addition, ALX-109 also enhanced the ability of aztreonam to reduce established PAO1 biofilms. Inhalation therapy combining hypothiocyanite and lactoferrin with TOBI(®) (tobramycin) or Cayston(®) (aztreonam) may be beneficial to CF patients by decreasing the airway bacterial burden of P. aeruginosa. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  18. Complex growing networks with intrinsic vertex fitness

    International Nuclear Information System (INIS)

    Bedogne, C.; Rodgers, G. J.

    2006-01-01

    One of the major questions in complex network research is to identify the range of mechanisms by which a complex network can self organize into a scale-free state. In this paper we investigate the interplay between a fitness linking mechanism and both random and preferential attachment. In our models, each vertex is assigned a fitness x, drawn from a probability distribution ρ(x). In Model A, at each time step a vertex is added and joined to an existing vertex, selected at random, with probability p and an edge is introduced between vertices with fitnesses x and y, with a rate f(x,y), with probability 1-p. Model B differs from Model A in that, with probability p, edges are added with preferential attachment rather than randomly. The analysis of Model A shows that, for every fixed fitness x, the network's degree distribution decays exponentially. In Model B we recover instead a power-law degree distribution whose exponent depends only on p, and we show how this result can be generalized. The properties of a number of particular networks are examined

  19. Origin of preferential flow and its controlling factors on emission potential using numerical simulations and lab experiments

    NARCIS (Netherlands)

    Baviskar, S.M.; Heimovaara, T.J.

    2015-01-01

    We believe the unsaturated and heterogeneous nature of landfills leads to the emergence of preferential pathways of water and dissolved compounds through the waste body. In this research we explore the origin of preferential flow in a porous media with a deterministic numerical model. In this model

  20. THE DISTRIBUTION OF PREFERENTIAL PATHS AND ITS RELATION TO THE SOIL CHARACTERISTICS IN THE THREE GORGES AREA, CHINA

    Institute of Scientific and Technical Information of China (English)

    Hongjiang ZHANG; Jinhua CHENG; Yuhu SHI; Yun CHENG

    2007-01-01

    To study the characteristics of the distribution of the preferential paths and the affecting factors in the Three Gorges area, four soil profiles were dug to observe the distribution of preferential paths in the Quxi watershed in the Yangtze River basin. The Morisita exponential test method was used to examine the distribution type of preferential paths. The physical properties and infiltration characteristics of the soil were also measured to evaluate their relationship to preferential paths. The results showed that in this area, preferential paths clustered and mainly distributed in the 80-100 cm soil layer, and along the interface between the weathered layer and semi-weathered layer. There were more non-capillary pores in the 83-110 cm layer than in the other layers. It can be derived that most non-capillary pores in this layer were preferential paths caused by geological processes and rotten plant roots. The percentage of coarse soil particles increased with the depth of the soil layer. In the deeper soil layer, the coarse soil particles helped the formation of preferential paths. The fastest steady infiltration rate was observed in the of 83-110cm layer, which is inferred to be due to the greater number of preferential paths.

  1. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  2. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  3. Preferential Alignment of Hydroxyapatite Crystallites in Nanocomposites with Chemically Disintegrated Silk Fibroin

    International Nuclear Information System (INIS)

    Nemoto, Rei; Wang Li; Ikoma, Toshiyuki; Tanaka, Junzo; Senna, Mamoru

    2004-01-01

    Hydroxyapatite (HAp) nanocrystals were prepared at room temperature by a coprecipitation method from Ca(OH) 2 and H 3 PO 4 , in the presence of chemically disintegrated silk fibroin (SF). Adsorbed amounts of cations on SF and crystallinity of HAp in the composite were increased by the chemical disintegration of SF higher order structure. Preferential alignment of c-axis of HAp crystallites along the longitudinal direction of ca. 150nm SF fibril was observed. These changes due to disintegration of SF were discussed in terms of the chemical interaction between HAp and SF. The resulted composite with preferential alignment of HAp nanocrystals is a good candidate as a starting material for bone substitutes

  4. Brain tumor initiating cells adapt to restricted nutrition through preferential glucose uptake.

    Science.gov (United States)

    Flavahan, William A; Wu, Qiulian; Hitomi, Masahiro; Rahim, Nasiha; Kim, Youngmi; Sloan, Andrew E; Weil, Robert J; Nakano, Ichiro; Sarkaria, Jann N; Stringer, Brett W; Day, Bryan W; Li, Meizhang; Lathia, Justin D; Rich, Jeremy N; Hjelmeland, Anita B

    2013-10-01

    Like all cancers, brain tumors require a continuous source of energy and molecular resources for new cell production. In normal brain, glucose is an essential neuronal fuel, but the blood-brain barrier limits its delivery. We now report that nutrient restriction contributes to tumor progression by enriching for brain tumor initiating cells (BTICs) owing to preferential BTIC survival and to adaptation of non-BTICs through acquisition of BTIC features. BTICs outcompete for glucose uptake by co-opting the high affinity neuronal glucose transporter, type 3 (Glut3, SLC2A3). BTICs preferentially express Glut3, and targeting Glut3 inhibits BTIC growth and tumorigenic potential. Glut3, but not Glut1, correlates with poor survival in brain tumors and other cancers; thus, tumor initiating cells may extract nutrients with high affinity. As altered metabolism represents a cancer hallmark, metabolic reprogramming may maintain the tumor hierarchy and portend poor prognosis.

  5. A Novel Preferential Diffusion Recommendation Algorithm Based on User’s Nearest Neighbors

    Directory of Open Access Journals (Sweden)

    Fuguo Zhang

    2017-01-01

    Full Text Available Recommender system is a very efficient way to deal with the problem of information overload for online users. In recent years, network based recommendation algorithms have demonstrated much better performance than the standard collaborative filtering methods. However, most of network based algorithms do not give a high enough weight to the influence of the target user’s nearest neighbors in the resource diffusion process, while a user or an object with high degree will obtain larger influence in the standard mass diffusion algorithm. In this paper, we propose a novel preferential diffusion recommendation algorithm considering the significance of the target user’s nearest neighbors and evaluate it in the three real-world data sets: MovieLens 100k, MovieLens 1M, and Epinions. Experiments results demonstrate that the novel preferential diffusion recommendation algorithm based on user’s nearest neighbors can significantly improve the recommendation accuracy and diversity.

  6. [Characters of infiltration and preferential flow of black soil in Northeast China under different tillage patterns].

    Science.gov (United States)

    Li, Wen-Feng; Zhang, Xiao-Ping; Liang, Ai-Zhen; Shen, Yan; Shi, Xiu-Huan; Luo, Jin-Ming; Yang, Xue-Ming

    2008-07-01

    By using dye tracer and double-ring infiltrometer techniques, the characters of infiltration and preferential flow of black soil under no-tillage (NT) and fall moldboard plow (MP) were compared after six years continuous management. The results showed that the infiltration rate was higher under NT than under MP. When the infiltration reached steady, the infiltration rate and accumulative infiltration capacity under NT were 1.35 and 1.44 times as high as those under MP, respectively. The penetration depth of methylene blue reached a depth of 43 cm in NT soil, being 16 cm deeper than that in MP soil. Comparing with MP soil, NT soil had better development of pore structure and more biological pores, and presented better preferential flow character, which were of importance for water infiltration and soil and water conservation.

  7. Epidemic propagation on adaptive coevolutionary networks with preferential local-world reconnecting strategy

    International Nuclear Information System (INIS)

    Song Yu-Rong; Jiang Guo-Ping; Gong Yong-Wang

    2013-01-01

    In the propagation of an epidemic in a population, individuals adaptively adjust their behavior to avoid the risk of an epidemic. Differently from existing studies where new links are established randomly, a local link is established preferentially in this paper. We propose a new preferentially reconnecting edge strategy depending on spatial distance (PR-SD). For the PR-SD strategy, the new link is established at random with probability p and in a shortest distance with the probability 1 − p. We establish the epidemic model on an adaptive network using Cellular Automata, and demonstrate the effectiveness of the proposed model by numerical simulations. The results show that the smaller the value of parameter p, the more difficult the epidemic spread is. The PR-SD strategy breaks long-range links and establishes as many short-range links as possible, which causes the network efficiency to decrease quickly and the propagation of the epidemic is restrained effectively. (general)

  8. THE EFFECT OF PREFERENTIAL TRADE AREAS (PTAs IN THE PERSPECTIVE OF REGIONALISM: THE CASE OF ASEAN

    Directory of Open Access Journals (Sweden)

    Abdurrahman Al-Faqiih

    2016-03-01

    Full Text Available The issue of regionalism particularly in the matter of preferential trade area is not an old fashion debate, but it becomes a prominent feature and a popular tool for global trading system. However, it does not mean that the regionalism might always bring benefit for any actor especially in terms of every national interest in the region. This paper would elaborate the effect of preferential trade area (PTAs establishment on the economic interest of ASEAN countries member. Through literature study, this paper concludes that the PTAs produce many positive benefits for the ASEAN countries member. The flexibility of partnerships and coverage selection under PTAs has helped ASEAN solve the crisis and increase efficiency as well as stimulate the main goal of global fair trade by expanding economic linkages. Thus, it could be said that PTAs enhance the multilateralism under the WTO system

  9. Estimation of Airline Benefits from Avionics Upgrade under Preferential Merge Re-sequence Scheduling

    Science.gov (United States)

    Kotegawa, Tatsuya; Cayabyab, Charlene Anne; Almog, Noam

    2013-01-01

    Modernization of the airline fleet avionics is essential to fully enable future technologies and procedures for increasing national airspace system capacity. However in the current national airspace system, system-wide benefits gained by avionics upgrade are not fully directed to aircraft/airlines that upgrade, resulting in slow fleet modernization rate. Preferential merge re-sequence scheduling is a best-equipped-best-served concept designed to incentivize avionics upgrade among airlines by allowing aircraft with new avionics (high-equipped) to be re-sequenced ahead of aircraft without the upgrades (low-equipped) at enroute merge waypoints. The goal of this study is to investigate the potential benefits gained or lost by airlines under a high or low-equipped fleet scenario if preferential merge resequence scheduling is implemented.

  10. Preferential emission of photon emulsion nuclei in high energy nuclear disintegration

    International Nuclear Information System (INIS)

    Sarkar, Subir; Bhattacharjee, B.; Goswami, T.D.

    1997-01-01

    In the present work an effort has been made to observe such preferential emission, if any, in the CNO group of photo emulsion nuclei. Here the angle between any two slow (β b = 3,4,5 and 6. Assuming the fragments to be emitted isotropically as expected from evaporation theory, possible angles between any two tracks are computed separately for disintegrating centres with the same number of N b

  11. Separation of Enantiomers by Preferential Crystallization: Mathematical Modeling of a Coupled Crystallizer Configuration

    DEFF Research Database (Denmark)

    Chaaban, Joussef Hussein; Dam-Johansen, Kim; Skovby, Tommy

    2014-01-01

    A mathematical model describing the separation of enantiomers by simultaneous preferential crystallization in a coupled crystallizer configuration is developed. The model was validated against experimental data for a chemical model compound, the conglomerate forming system of asparagine monohydrate....... The racemic compound and the pure enantiomer can be separated simultaneously in each crystallizer, having sufficient enrichment of the pure enantiomer in the feed solution. The model can also be extended to represent a fully continuous separation process taking into account the continuous supply...

  12. Self-potential monitoring of a thermal pulse advecting through a preferential flow path

    Science.gov (United States)

    Ikard, S. J.; Revil, A.

    2014-11-01

    There is a need to develop new non-intrusive geophysical methods to detect preferential flow paths in heterogeneous porous media. A laboratory experiment is performed to non-invasively localize a preferential flow pathway in a sandbox using a heat pulse monitored by time-lapse self-potential measurements. Our goal is to investigate the amplitude of the intrinsic thermoelectric self-potential anomalies and the ability of this method to track preferential flow paths. A negative self-potential anomaly (-10 to -15 mV with respect to the background signals) is observed at the surface of the tank after hot water is injected in the upstream reservoir during steady state flow between the upstream and downstream reservoirs of the sandbox. Repeating the same experiment with the same volume of water injected upstream, but at the same temperature as the background pore water, produces a negligible self-potential anomaly. The negative self-potential anomaly is possibly associated with an intrinsic thermoelectric effect, with the temperature dependence of the streaming potential coupling coefficient, or with an apparent thermoelectric effect associated with the temperature dependence of the electrodes themselves. We model the experiment in 3D using a finite element code. Our results show that time-lapse self-potential signals can be used to track the position of traveling heat flow pulses in saturated porous materials, and therefore to find preferential flow pathways, especially in a very permeable environment and in real time. The numerical model and the data allows quantifying the intrinsic thermoelectric coupling coefficient, which is on the order of -0.3 to -1.8 mV per degree Celsius. The temperature dependence of the streaming potential during the experiment is negligible with respect to the intrinsic thermoelectric coupling. However, the temperature dependence of the potential of the electrodes needs to be accounted for and is far from being negligible if the electrodes

  13. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing

    OpenAIRE

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-01-01

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Conseq...

  14. Comments on possible preferential order-disorder in A-15 compounds based upon Nb

    International Nuclear Information System (INIS)

    Cox, D.E.

    1977-01-01

    The possible existence of preferential B-site disorder in A-15 compounds recently claimed on the basis of x-ray powder diffraction data but questioned from the viewpoint of known phase diagrams is examined for some Nb-based compounds of this type. It is concluded that x-ray powder data do not allow the determination of both order and compositional variables as suggested, and the latter must therefore be determined by some other method. (author)

  15. Preferential Trade Agreements and the Law and Politics of GATT Article XXIV

    DEFF Research Database (Denmark)

    Alavi, Amin

    2010-01-01

    The tasks Preferential Trade Agreements (PTAs) perform are expressed in their scope and covered issues, thus in order to be WTO compatible these aspects of PTAs should comply with the relevant WTO rules. This paper examines which aspects of PTAs can violate these rules and therefore can be challe...... be challenged before the WTO Dis-pute Settlement Body, who may initiate such cases and why there hasn´t been more cases dealing with this im-portant issue....

  16. Are Preferential Trade Agreements with Non-trade Objectives a Stumbling Block for Multilateral Liberalization?

    OpenAIRE

    Nuno Limão

    2007-01-01

    In many preferential trade agreements (PTAs), countries exchange not only reductions in trade barriers but also cooperation in non-trade issues such as labour and environmental standards, intellectual property, etc. We provide a model of PTAs motivated by cooperation in non-trade issues and analyse its implications for global free trade and welfare. We find that such PTAs increase the cost of multilateral tariff reductions and thus cause a stumbling block to global free trade. This occurs bec...

  17. Solution thermodynamics and preferential solvation of sulfamethazine in (methanol + water) mixtures

    International Nuclear Information System (INIS)

    Delgado, Daniel R.; Almanza, Ovidio A.; Martínez, Fleming; Peña, María A.; Jouyban, Abolghasem; Acree, William E.

    2016-01-01

    Highlights: • Solubility of sulfamethazine (SMT) was measured in (methanol + water) mixtures. • SMT solubility was correlated with Jouyban–Acree model. • Gibbs energy, enthalpy, and entropy of dissolution of SMT were calculated. • Non-linear enthalpy–entropy relationship was observed for SMT. • Preferential solvation of SMT by methanol was analyzed by using the IKBI method. - Abstract: The solubility of sulfamethazine (SMT) in {methanol (1) + water (2)} co-solvent mixtures was determined at five different temperatures from (293.15 to 313.15) K. The sulfonamide exhibited its highest mole fraction solubility in pure methanol (δ 1 = 29.6 MPa 1/2 ) and its lowest mole fraction solubility in water (δ 2 = 47.8 MPa 1/2 ) at each of the five temperatures studied. The Jouyban–Acree model was used to correlate/predict the solubility values. The respective apparent thermodynamic functions Gibbs energy, enthalpy, and entropy of solution were obtained from the solubility data through the van’t Hoff and Gibbs equations. Apparent thermodynamic quantities of mixing were also calculated for this drug using values of the ideal solubility reported in the literature. A non-linear enthalpy–entropy relationship was noted for SMT in plots of both the enthalpy vs. Gibbs energy of mixing and the enthalpy vs. entropy of mixing. These plots suggest two different trends according to the slopes obtained when the composition of the mixtures changes. Accordingly, the mechanism for SMT transfer processes in water-rich mixtures from water to the mixture with 0.70 in mass fraction of methanol is entropy driven. Conversely, the mechanism is enthalpy driven in mixtures whenever the methanol composition exceeds 0.70 mol fraction. An inverse Kirkwood–Buff integral analysis of the preferential solvation of SMT indicated that the drug is preferentially solvated by water in water-rich mixtures but is preferentially solvated by methanol in methanol-rich mixtures.

  18. Post-learning hippocampal dynamics promote preferential retention of rewarding events

    Science.gov (United States)

    Gruber, Matthias J.; Ritchey, Maureen; Wang, Shao-Fang; Doss, Manoj K.; Ranganath, Charan

    2016-01-01

    Reward motivation is known to modulate memory encoding, and this effect depends on interactions between the substantia nigra/ ventral tegmental area complex (SN/VTA) and the hippocampus. It is unknown, however, whether these interactions influence offline neural activity in the human brain that is thought to promote memory consolidation. Here, we used functional magnetic resonance imaging (fMRI) to test the effect of reward motivation on post-learning neural dynamics and subsequent memory for objects that were learned in high- or low-reward motivation contexts. We found that post-learning increases in resting-state functional connectivity between the SN/VTA and hippocampus predicted preferential retention of objects that were learned in high-reward contexts. In addition, multivariate pattern classification revealed that hippocampal representations of high-reward contexts were preferentially reactivated during post-learning rest, and the number of hippocampal reactivations was predictive of preferential retention of items learned in high-reward contexts. These findings indicate that reward motivation alters offline post-learning dynamics between the SN/VTA and hippocampus, providing novel evidence for a potential mechanism by which reward could influence memory consolidation. PMID:26875624

  19. Effects of fine root length density and root biomass on soil preferential flow in forest ecosystems

    Directory of Open Access Journals (Sweden)

    Yinghu Zhang

    2015-04-01

    Full Text Available Aim of study: The study was conducted to characterize the impacts of plant roots systems (e.g., root length density and root biomass on soil preferential flow in forest ecosystems. Area of study: The study was carried out in Jiufeng National Forest Park, Beijing, China. Material and methods: The flow patterns were measured by field dye tracing experiments. Different species (Sophora japonica Linn,Platycladus orientalis Franco, Quercus dentata Thunbwere quantified in two replicates, and 12 soil depth were applied. Plant roots were sampled in the sieving methods. Root length density and root biomass were measured by WinRHIZO. Dye coverage was implied in the image analysis, and maximum depth of dye infiltration by direct measurement. Main results: Root length density and root biomass decreased with the increasing distance from soil surface, and root length density was 81.6% higher in preferential pathways than in soil matrix, and 66.7% for root biomass with respect to all experimental plots. Plant roots were densely distributed in the upper soil layers. Dye coverage was almost 100% in the upper 5-10 cm, but then decreased rapidly with soil depth. Root length density and root biomass were different from species: Platycladus orientalis Franco > Quercus dentata Thunb > Sophora japonica Linn. Research highlights: The results indicated that fine roots systems had strong effects on soil preferential flow, particularly root channels enhancing nutrition transport across soil profiles in forest dynamics.

  20. Dihydroartemisinin induces apoptosis preferentially via a Bim-mediated intrinsic pathway in hepatocarcinoma cells.

    Science.gov (United States)

    Qin, Guiqi; Zhao, ChuBiao; Zhang, Lili; Liu, Hongyu; Quan, Yingyao; Chai, Liuying; Wu, Shengnan; Wang, Xiaoping; Chen, Tongsheng

    2015-08-01

    This report is designed to dissect the detail molecular mechanism by which dihydroartemisinin (DHA), a derivative of artemisinin, induces apoptosis in human hepatocellular carcinoma (HCC) cells. DHA induced a loss of the mitochondrial transmemberane potential (ΔΨm), release of cytochrome c, activation of caspases, and externalization of phosphatidylserine indicative of apoptosis induction. Compared with the modest inhibitory effects of silencing Bax, silencing Bak largely prevented DHA-induced ΔΨm collapse and apoptosis though DHA induced a commensurable activation of Bax and Bak, demonstrating a key role of the Bak-mediated intrinsic apoptosis pathway. DHA did not induce Bid cleavage and translocation from cytoplasm to mitochondria and had little effects on the expressions of Puma and Noxa, but did increase Bim and Bak expressions and decrease Mcl-1 expression. Furthermore, the cytotoxicity of DHA was remarkably reduced by silencing Bim, and modestly but significantly reduced by silencing Puma or Noxa. Silencing Bim or Noxa preferentially reduced DHA-induced Bak activation, while silencing Puma preferentially reduced DHA-induced Bax activation, demonstrating that Bim and to a lesser extent Noxa act as upstream mediators to trigger the Bak-mediated intrinsic apoptosis pathway. In addition, silencing Mcl-1 enhanced DHA-induced Bak activation and apoptosis. Taken together, our data demonstrate a crucial role of Bim in preferentially regulating the Bak/Mcl-1 rheostat to mediate DHA-induced apoptosis in HCC cells.

  1. Effects of preferential concentration on direct radiation transmission in a turbulent duct flow

    Science.gov (United States)

    Villafane, Laura; Banko, Andrew; Kim, Ji Hoon; Elkins, Chris; Eaton, John

    2017-11-01

    Inertial particles in turbulent flows preferentially concentrate, giving rise to spatial and temporal fluctuations of particle number density that affect radiation transmission through the medium. Positive particle correlations enhance direct transmission when compared to the exponential attenuation predicted by the Beer's Law for randomly distributed particles. In the context of a particle based solar receiver, this work studies the effects of preferential concentration and optical depth on direct transmission through a particle laden turbulent duct flow. Time resolved measurements of transmission through the mixture were performed for various particle loadings and Reynolds numbers, thus varying particle correlation lengths, optical depth and concentration fluctuations. These measurements were made using a photodiode to record the transmission of a collimated laser beam along the wall bisector of the duct. A synchronized high-speed camera provided particle positions along most of the beam path. Average and fluctuating radiation transmission results are compared to predictions derived from the imaged number density fields and to simplified analytical models. Simplified models are able to capture the correct trends with varying loading and preferential concentration. This work is funded by the Department of Energy's National Nuclear Security Administration, Grant #DE-NA0002373-1.

  2. Preferential radiosensitization of G1 checkpoint--deficient cells by methylxanthines

    International Nuclear Information System (INIS)

    Russell, Kenneth J.; Wiens, Linda W.; Demers, G. William; Galloway, Denise A.; Le, Tiep; Rice, Glenn C.; Bianco, James A.; Singer, Jack W.; Groudine, Mark

    1996-01-01

    Purpose: To develop a checkpoint-based strategy for preferential radiosensitization of human tumors with deficient and/or mutant p53. Methods and Materials: A549 human lung adenocarcinoma cell lines differing in their expression of the p53 tumor suppressor gene were produced by transduction with the E6 oncogene from human papilloma virus type 16. The cells expressing E6 (E6+) lack a G1 arrest in response to ionizing radiation, are deficient in p53 and p21 expression, and exhibit a fivefold greater clonogenic survival following 10 Gy radiation. Results: Postirradiation incubation with millimolar concentrations of the methylxanthine pentoxifylline (PTX) results in preferential radiosensitization of the E6+ cells compared to the LXSN+ vector transduced controls. There is a threefold sensitization of the LXSN+ cells and a 15-fold sensitization of the E6+ cells, which results in equal clonogenic survival of the two lines. Flow cytometry reveals PTX abrogation of the radiation induced G2 arrest for both cell lines. PTX also prolongs G1 transit for both cell lines. Preliminary results are presented using a novel methylxanthine, lisofylline (LSF), which has similar cell cycle effects on G1 and G2 and achieves differential radiosensitization at micromolar concentrations that are sustainable in humans. Conclusions: This checkpoint-based strategy is a promising approach for achieving preferential radiosensitization of p53- tumors relative to p53+ normal tissues

  3. Preferential transfer of certain plasma membrane proteins onto T and B cells by trogocytosis.

    Directory of Open Access Journals (Sweden)

    Sandrine Daubeuf

    2010-01-01

    Full Text Available T and B cells capture antigens via membrane fragments of antigen presenting cells (APC in a process termed trogocytosis. Whether (and how a preferential transfer of some APC components occurs during trogocytosis is still largely unknown. We analyzed the transfer onto murine T and B cells of a large panel of fluorescent proteins with different intra-cellular localizations in the APC or various types of anchors in the plasma membrane (PM. Only the latter were transferred by trogocytosis, albeit with different efficiencies. Unexpectedly, proteins anchored to the PM's cytoplasmic face, or recruited to it via interaction with phosphinositides, were more efficiently transferred than those facing the outside of the cell. For proteins spanning the PM's whole width, transfer efficiency was found to vary quite substantially, with tetraspanins, CD4 and FcRgamma found among the most efficiently transferred proteins. We exploited our findings to set immunodiagnostic assays based on the capture of preferentially transferred components onto T or B cells. The preferential transfer documented here should prove useful in deciphering the cellular structures involved in trogocytosis.

  4. Geostatistical integration and uncertainty in pollutant concentration surface under preferential sampling

    Directory of Open Access Journals (Sweden)

    Laura Grisotto

    2016-04-01

    Full Text Available In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main interest in statistical integration and uncertainty. We used PM10 data arising from the air quality network of the Environmental Protection Agency of Lombardy Region (Italy and numerical outputs from the deterministic model. We specified an inhomogeneous Poisson process for the sampling locations intensities and a shared spatial random component model for the dependence between the spatial location of monitors and the pollution surface. We found greater predicted standard deviation differences in areas not properly covered by the air quality network. In conclusion, in this context inferences on prediction uncertainty may be misleading when geostatistical modelling does not take into account preferential sampling.

  5. Telomerase and Tel1p Preferentially Associate with Short Telomeres in S. cerevisiae

    Science.gov (United States)

    Sabourin, Michelle; Tuzon, Creighton T.; Zakian, Virginia A.

    2009-01-01

    SUMMARY In diverse organisms, telomerase preferentially elongates short telomeres. We generated a single short telomere in otherwise wild-type (WT) S. cerevisiae cells. The binding of the positive regulators Ku and Cdc13p was similar at short and WT-length telomeres. The negative regulators Rif1p and Rif2p were present at the short telomere, although Rif2p levels were reduced. Two telomerase holoenzyme components, Est1p and Est2p, were preferentially enriched at short telomeres in late S/G2 phase, the time of telomerase action. Tel1p, the yeast ATM-like checkpoint kinase, was highly enriched at short telomeres from early S through G2 phase and even into the next cell cycle. Nonetheless, induction of a single short telomere did not elicit a cell-cycle arrest. Tel1p binding was dependent on Xrs2p and required for preferential binding of telomerase to short telomeres. These data suggest that Tel1p targets telomerase to the DNA ends most in need of extension. PMID:17656141

  6. Beneficial Effect of Preferential Music on Exercise Induced Changes in Heart Rate Variability.

    Science.gov (United States)

    Archana, R; Mukilan, R

    2016-05-01

    Music is known to reduce pain, anxiety and fear in several stressful conditions in both males and females. Further, listening to preferred music enhances the endurance during running performance of women rather than listening to non-preferred music. In recent years Heart Rate Variability (HRV) has been used as an indicator of autonomic nervous activity. This study was aimed to assess the effectiveness of preferential music on HRV after moderate exercise. This was an experimental study done in 30 healthy students aged between 20-25 years, of either sex. HRV was measured at rest, 15 minutes of exercise only and 15 minutes of exercise with listening preferential music in same participants. Data was analysed by One-Way ANOVA and Tukey HSD Post-hoc Test. Statistical significance was taken to be a p-value of less than 0.05. Low frequency and high frequency component was significantly increased followed by only exercise. Music minimized increase in both high and low frequency component followed by exercise. However, only high frequency change was statistically significant. LF/HF ratio was significantly increased followed by only exercise. Music significantly minimized increase in LF/HF ratio. This study provides the preliminary evidence that listening to preferential music could be an effective method of relaxation, as indicated by a shift of the autonomic balance towards the parasympathetic activity among medical students.

  7. PAFit: A Statistical Method for Measuring Preferential Attachment in Temporal Complex Networks.

    Directory of Open Access Journals (Sweden)

    Thong Pham

    Full Text Available Preferential attachment is a stochastic process that has been proposed to explain certain topological features characteristic of complex networks from diverse domains. The systematic investigation of preferential attachment is an important area of research in network science, not only for the theoretical matter of verifying whether this hypothesized process is operative in real-world networks, but also for the practical insights that follow from knowledge of its functional form. Here we describe a maximum likelihood based estimation method for the measurement of preferential attachment in temporal complex networks. We call the method PAFit, and implement it in an R package of the same name. PAFit constitutes an advance over previous methods primarily because we based it on a nonparametric statistical framework that enables attachment kernel estimation free of any assumptions about its functional form. We show this results in PAFit outperforming the popular methods of Jeong and Newman in Monte Carlo simulations. What is more, we found that the application of PAFit to a publically available Flickr social network dataset yielded clear evidence for a deviation of the attachment kernel from the popularly assumed log-linear form. Independent of our main work, we provide a correction to a consequential error in Newman's original method which had evidently gone unnoticed since its publication over a decade ago.

  8. Visualization of airflow growing soap bubbles

    Science.gov (United States)

    Al Rahbi, Hamood; Bock, Matthew; Ryu, Sangjin

    2016-11-01

    Visualizing airflow inside growing soap bubbles can answer questions regarding the fluid dynamics of soap bubble blowing, which is a model system for flows with a gas-liquid-gas interface. Also, understanding the soap bubble blowing process is practical because it can contribute to controlling industrial processes similar to soap bubble blowing. In this study, we visualized airflow which grows soap bubbles using the smoke wire technique to understand how airflow blows soap bubbles. The soap bubble blower setup was built to mimic the human blowing process of soap bubbles, which consists of a blower, a nozzle and a bubble ring. The smoke wire was placed between the nozzle and the bubble ring, and smoke-visualized airflow was captured using a high speed camera. Our visualization shows how air jet flows into the growing soap bubble on the ring and how the airflow interacts with the soap film of growing bubble.

  9. Anticipated ethical challenges with growing molecular prenatal ...

    African Journals Online (AJOL)

    Anticipated ethical challenges with growing molecular prenatal diagnosis in Nigeria. ... Bayero Journal of Pure and Applied Sciences ... Ethical standards in medical laboratories are derived from medical ethics therefore, the four fundamental ...

  10. Growing America's Energy Future

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    The emerging U.S. bioenergy industry provides a secure and growing supply of transportation fuels, biopower, and bioproducts produced from a range of abundant, renewable biomass resources. Bioenergy can help ensure a secure, sustainable, and economically sound future by reducing U.S. dependence on foreign oil, developing domestic clean energy sources, and generating domestic green jobs. Bioenergy can also help address growing concerns about climate change by reducing greenhouse gas emissions to create a healthier environment for current and future generations.

  11. Modelling rapid subsurface flow at the hillslope scale with explicit representation of preferential flow paths

    Science.gov (United States)

    Wienhöfer, J.; Zehe, E.

    2012-04-01

    Rapid lateral flow processes via preferential flow paths are widely accepted to play a key role for rainfall-runoff response in temperate humid headwater catchments. A quantitative description of these processes, however, is still a major challenge in hydrological research, not least because detailed information about the architecture of subsurface flow paths are often impossible to obtain at a natural site without disturbing the system. Our study combines physically based modelling and field observations with the objective to better understand how flow network configurations influence the hydrological response of hillslopes. The system under investigation is a forested hillslope with a small perennial spring at the study area Heumöser, a headwater catchment of the Dornbirnerach in Vorarlberg, Austria. In-situ points measurements of field-saturated hydraulic conductivity and dye staining experiments at the plot scale revealed that shrinkage cracks and biogenic macropores function as preferential flow paths in the fine-textured soils of the study area, and these preferential flow structures were active in fast subsurface transport of artificial tracers at the hillslope scale. For modelling of water and solute transport, we followed the approach of implementing preferential flow paths as spatially explicit structures of high hydraulic conductivity and low retention within the 2D process-based model CATFLOW. Many potential configurations of the flow path network were generated as realisations of a stochastic process informed by macropore characteristics derived from the plot scale observations. Together with different realisations of soil hydraulic parameters, this approach results in a Monte Carlo study. The model setups were used for short-term simulation of a sprinkling and tracer experiment, and the results were evaluated against measured discharges and tracer breakthrough curves. Although both criteria were taken for model evaluation, still several model setups

  12. Motility and chemotaxis mediate the preferential colonization of gastric injury sites by Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Eitaro Aihara

    2014-07-01

    Full Text Available Helicobacter pylori (H. pylori is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1 significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB or chemotaxis (ΔcheY. ΔmotB (10(6 failed to colonize ulcerated or healthy stomach tissue. ΔcheY (10(6 colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites

  13. Depth resolution and preferential sputtering in depth profiling of sharp interfaces

    International Nuclear Information System (INIS)

    Hofmann, S.; Han, Y.S.; Wang, J.Y.

    2017-01-01

    Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

  14. Depth resolution and preferential sputtering in depth profiling of sharp interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Han, Y.S. [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China); Wang, J.Y., E-mail: wangjy@stu.edu.cn [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China)

    2017-07-15

    Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

  15. A Review on Preferential Oxidation of Carbon Monoxide in Hydrogen Rich Gases

    Directory of Open Access Journals (Sweden)

    A. Mishra

    2011-05-01

    Full Text Available In this review, recent works on the preferential oxidation of carbon monoxide in hydrogen rich gases for fuel cell applications are summarized. H2 is used as a fuel for polymer-electrolyte membrane fuel cell (PEMFC. It is produced by reforming of natural gas or liquid fuels followed by water gas shift reaction. The produced gas consists of H2, CO, and CO2. In which CO content is around 1%, which is highly poisonous for the Pt anode of the PEMFC so that further removal of CO is needed. Catalytic preferential oxidation of CO (CO-PROX is one of the most suitable methods of purification of H2 because of high CO conversion rate at low temperature range, which is preferable for PEMFC operating conditions. Catalysts used for COPROX are mainly noble metal based; gold based and base metal oxide catalysts among them Copper-Ceria based catalysts are the most appropriate due to its low cost, easy availability and result obtained by these catalysts are comparable with the conventional noble metal catalysts. Copyright © 2011 BCREC UNDIP. All rights reserved(Received: 22nd October 2010, Revised: 12nd January 2011, Accepted: 19th January 2011[How to Cite: A. Mishra, R. Prasad. (2011. A Review on Preferential Oxidation of Carbon Monoxide in Hydrogen Rich Gases. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (1: 1-14. doi:10.9767/bcrec.6.1.191.1-14][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.191.1-14 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/191] | View in 

  16. Detection of preferential particle orientation in the atmosphere: Development of an alternative polarization lidar system

    International Nuclear Information System (INIS)

    Geier, Manfred; Arienti, Marco

    2014-01-01

    Increasing interest in polarimetric characterization of atmospheric aerosols has led to the development of complete sample-measuring (Mueller) polarimeters that are capable of measuring the entire backscattering phase matrix of a probed volume. These Mueller polarimeters consist of several moving parts, which limit measurement rates and complicate data analysis. In this paper, we present the concept of a less complex polarization lidar setup for detection of preferential orientation of atmospheric particulates. On the basis of theoretical considerations of data inversion stability and propagation of measurement uncertainties, an optimum optical configuration is established for two modes of operation (with either a linear or a circular polarized incident laser beam). The conceptualized setup falls in the category of incomplete sample-measuring polarimeters and uses four detection channels for simultaneous measurement of the backscattered light. The expected performance characteristics are discussed through an example of a typical aerosol with a small fraction of particles oriented in a preferred direction. The theoretical analysis suggests that achievable accuracies in backscatter cross-sections and depolarization ratios are similar to those with conventional two-channel configurations, while in addition preferential orientation can be detected with the proposed four-channel system for a wide range of conditions. - Highlights: • A theoretical study of a new four-channel lidar concept is offered. • Preferential particle orientation detection could be realized with minor device modifications. • The proposed configuration is optimized to balance inversion uncertainties. • Circular polarized beam is demonstrated to provide the best noise performance. • Operation with ultra-short pulses is proposed to quantify particle number density

  17. Characterization of the preferential movement of elements during sputtering of binary targets

    International Nuclear Information System (INIS)

    Davarya, F.

    1982-01-01

    The knowledge of the physics of ion bombardment effects has matured considerably during the last decade. This has generated an ever increasing number of new applications and the subsequent need for better understanding of the collisional interaction, especially in bombardment of multicomponent materials. This research investigates the near-surface composition changes due to the preferential movement of target elements in binary systems under ion bombardment. The Monte-Carlo code EVOLVE, which has been developed at the University of Maryland for ion transport studies, has been utilized for these investigations. The effects of differences in three key parameters, surface binding energy, displacement energy, and mass of target elements have been studied. It has been observed that in the absence of any binding energy differences, the effect of the mass difference of target elements is contrary to the previously commonly held belief that the lighter target elements tend to be preferentially implanted inward relative to the heavier elements. Cases are presented where preferential inward movement of the heavier elements were observed. Further studies were carried out using EVOLVE and it has been observed that the heavier elements, while having shorter path length relative to the lighter elements, have a longer projected penetration depth. Due to the lack of standard reference materials (SRM's) for studing ion bombardment effects, quantitative comparison of results obtained using different techniques has been unreliable. In an effort to help resolve this need, multilayered thin-film structures (prepared for SRM use) have been studied using both experimental techniques and computer simulaton. The characteristics of those structures which are useful for SMR application, such as layer thickness, layer periodicity, and interface widths are presented

  18. Scale-free behavior of networks with the copresence of preferential and uniform attachment rules

    Science.gov (United States)

    Pachon, Angelica; Sacerdote, Laura; Yang, Shuyi

    2018-05-01

    Complex networks in different areas exhibit degree distributions with a heavy upper tail. A preferential attachment mechanism in a growth process produces a graph with this feature. We herein investigate a variant of the simple preferential attachment model, whose modifications are interesting for two main reasons: to analyze more realistic models and to study the robustness of the scale-free behavior of the degree distribution. We introduce and study a model which takes into account two different attachment rules: a preferential attachment mechanism (with probability 1 - p) that stresses the rich get richer system, and a uniform choice (with probability p) for the most recent nodes, i.e. the nodes belonging to a window of size w to the left of the last born node. The latter highlights a trend to select one of the last added nodes when no information is available. The recent nodes can be either a given fixed number or a proportion (αn) of the total number of existing nodes. In the first case, we prove that this model exhibits an asymptotically power-law degree distribution. The same result is then illustrated through simulations in the second case. When the window of recent nodes has a constant size, we herein prove that the presence of the uniform rule delays the starting time from which the asymptotic regime starts to hold. The mean number of nodes of degree k and the asymptotic degree distribution are also determined analytically. Finally, a sensitivity analysis on the parameters of the model is performed.

  19. Spatial connectivity in a highly heterogeneous aquifer: From cores to preferential flow paths

    Science.gov (United States)

    Bianchi, M.; Zheng, C.; Wilson, C.; Tick, G.R.; Liu, Gaisheng; Gorelick, S.M.

    2011-01-01

    This study investigates connectivity in a small portion of the extremely heterogeneous aquifer at the Macrodispersion Experiment (MADE) site in Columbus, Mississippi. A total of 19 fully penetrating soil cores were collected from a rectangular grid of 4 m by 4 m. Detailed grain size analysis was performed on 5 cm segments of each core, yielding 1740 hydraulic conductivity (K) estimates. Three different geostatistical simulation methods were used to generate 3-D conditional realizations of the K field for the sampled block. Particle tracking calculations showed that the fastest particles, as represented by the first 5% to arrive, converge along preferential flow paths and exit the model domain within preferred areas. These 5% fastest flow paths accounted for about 40% of the flow. The distribution of preferential flow paths and particle exit locations is clearly influenced by the occurrence of clusters formed by interconnected cells with K equal to or greater than the 0.9 decile of the data distribution (10% of the volume). The fraction of particle paths within the high-K clusters ranges from 43% to 69%. In variogram-based K fields, some of the fastest paths are through media with lower K values, suggesting that transport connectivity may not require fully connected zones of relatively homogenous K. The high degree of flow and transport connectivity was confirmed by the values of two groups of connectivity indicators. In particular, the ratio between effective and geometric mean K (on average, about 2) and the ratio between the average arrival time and the arrival time of the fastest particles (on average, about 9) are consistent with flow and advective transport behavior characterized by channeling along preferential flow paths. ?? 2011 by the American Geophysical Union.

  20. Preferential production and transport of grass-derived pyrogenic carbon in NE-Australian savanna ecosystems

    Science.gov (United States)

    Saiz, Gustavo; Goodrick, Iain; Wurster, Christopher; Nelson, Paul N.; Wynn, Jonathan; Bird, Michael

    2017-12-01

    Understanding the main factors driving fire regimes in grasslands and savannas is critical to better manage their biodiversity and functions. Moreover, improving our knowledge on pyrogenic carbon (PyC) dynamics, including formation, transport and deposition, is fundamental to better understand a significant slow-cycling component of the global carbon cycle, particularly as these ecosystems account for a substantial proportion of the area globally burnt. However, a thorough assessment of past fire regimes in grass-dominated ecosystems is problematic due to challenges in interpreting the charcoal record of sediments. It is therefore critical to adopt appropriate sampling and analytical methods to allow the acquisition of reliable data and information on savanna fire dynamics. This study uses hydrogen pyrolysis (HyPy) to quantify PyC abundance and stable isotope composition (δ13C) in recent sediments across 38 micro-catchments covering a wide range of mixed C3/C4 vegetation in north Queensland, Australia. We exploited the contrasting δ13C values of grasses (i.e. C4; δ13C >-15‰) and woody vegetation (i.e. C3; δ13C <-24‰) to assess the preferential production and transport of grass-derived PyC in savanna ecosystems. Analyses were conducted on bulk and size-fractionated samples to determine the fractions into which PyC preferentially accumulates. Our data show that the δ13C value of PyC in the sediments is decoupled from the δ13C value of total organic carbon, which suggests that a significant component of PyC may be derived from incomplete grass combustion, even when the proportion of C4 grass biomass in the catchment was relatively small. Furthermore, we conducted 16 experimental burns that indicate that there is a comminution of PyC produced in-situ to smaller particles, which facilitates the transport of this material, potentially affecting its preservation potential. Savanna fires preferentially burn the grass understory rather than large trees, leading to

  1. Characterization and quantification of preferential flow in fractured rock systems, using resistivity tomography

    CSIR Research Space (South Africa)

    May, F

    2010-11-01

    Full Text Available , N Jovanovic2 and A Rozanov1 University of Stellenbosch1 and Council for Scientific and Industrial Research (CSIR)2 Characterization and quantification of preferential flow in fractured rock systems, using resistivity tomography Introduction... of slow and fast flowing pathways. Materials and Methods TABLE 1 DATE, TIME AND WEATHER CONDITIONS DURING RESISTIVITY TOMOGRAPHY SURVEY Survey No. Date Start time End time Precipitation (mm) Description KB001 8/27/2010 12H00 13H40 0.0 Sunny KB002 8...

  2. Pressure-induced preferential growth of nanocrystals in amorphous Nd9Fe85B6

    International Nuclear Information System (INIS)

    Wu Wei; Li Wei; Sun Hongyu; Li Hui; Zhang Xiangyi; Li Xiaohong; Liu Baoting

    2008-01-01

    Control over the growth and crystallographic orientation of nanocrystals in amorphous alloys is of particular importance for the development of advanced nanocrystalline materials. In the present study, Nd 2 Fe 14 B nanocrystals with a strong crystallographic texture along the [410] direction have been produced in Nd-lean amorphous Nd 9 Fe 85 B 6 under a high pressure of 6 GPa at 923 K. This is attributed to the high pressure inducing the preferential growth of Nd 2 Fe 14 B nanocrystals in the alloy. The present study demonstrates the potential application of high-pressure technology in controlling nanocrystalline orientation in amorphous alloys

  3. Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

    Science.gov (United States)

    Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

    2016-09-21

    Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

  4. A Little Salesmanship "Grows" a Long Way

    Science.gov (United States)

    Montas, Leah

    2012-01-01

    Goshen Elementary PTA's membership shrank the first year the author was PTA president. In the back of her mind, she was bothered by the fact that their membership numbers had dropped. So, after she attended a regional session with her vice president on growing membership, she got the courage to propose something different. They discussed with…

  5. Growing Income Inequality Threatens American Education

    Science.gov (United States)

    Duncan, Greg J.; Murnane, Richard J.

    2014-01-01

    The first of two articles in consecutive months describes the origins and nature of growing income inequality, and some of its consequences for American children. It documents the increased family income inequality that's occurred over the past 40 years and shows that the increased income disparity has been more than matched by an expanding…

  6. Level crossing analysis of growing surfaces

    International Nuclear Information System (INIS)

    Shahbazi, F; Sobhanian, S; Tabar, M Reza Rahimi; Khorram, S; Frootan, G R; Zahed, H

    2003-01-01

    We investigate the average frequency of positive slope ν + α , crossing the height α = h - h-bar in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities is given

  7. The Growing Diversity of Work Schedules.

    Science.gov (United States)

    Smith, Shirley J.

    1986-01-01

    The author highlights the predominance of the five-day, 40-hour workweek. Although finding little change in recent years in the proportion of workers on 40-hour schedules, Smith notes that there have been some changes in work patterns, with a still small but growing group of workers on "compressed" full-time weeks of less than five days.…

  8. Protect Your Health as You Grow Older

    Science.gov (United States)

    ... you get older. It’s important to: Keep your body and mind active Choose healthy foods Get enough sleep Talk to your doctor ... Just like physical activity is good for your body, activities that challenge your ... your brain healthy. As you grow older, it's important to: Learn ...

  9. Cyber threat intelligence exchange: A growing requirement

    CSIR Research Space (South Africa)

    Veerasamy, Namosha

    2017-06-01

    Full Text Available Managing the rise of cyber-attacks has become a growing challenge. Cyber space has become a battleground of threats ranging from malware to phishing, spam and password theft. Cybersecurity solutions mainly try to take a defensive stance and build a...

  10. Growing a New Generation of Music Teachers

    Science.gov (United States)

    Burrack, Frederick

    2009-01-01

    In many parts of the United States, there is a growing shortage of music teachers to take the place of the retiring teachers. This is most evident in rural areas. If music teachers are not available to fill openings, music positions are sometimes combined, spreading music teachers too thin and requiring them to possess multiple music…

  11. Pueblo Girls: Growing Up in Two Worlds.

    Science.gov (United States)

    Keegan, Marcia

    This book portrays San Ildefonso Pueblo on the east bank of the Rio Grande river in New Mexico through the lives of Sonja, age 10, and her sister Desiree, age 8. Growing up in San Ildefonso Pueblo, the girls enjoy the same activities as other American girls, such as basketball, cheerleading, playing video games, and sending e-mail. But they also…

  12. IntelliGrow 2.0

    DEFF Research Database (Denmark)

    Markvart, Jakob; Aaslyng, Jesper Peter Mazanti; Kalita, Sebastian

    2008-01-01

    the system in full scale in five Danish commercial nurseries. The four steps to reach the goal are: 1) development of a demonstrator giving the grower advice on optimal climate control based on the IntelliGrow concept 2) testing the demonstrator at research facilities followed by tests at growers 3...

  13. Preliminary characterization of slow growing rhizobial strains ...

    African Journals Online (AJOL)

    In this paper, we did some preliminary characterization of six slow growing rhizobial strains, isolated from Retama monosperma (L.) Boiss. root nodules sampled from 3 sites along the coast of Oran (CapeFalcon, Bousfer and MersElHadjadj) in Northwestern Algeria. Results of this study showed that all strains had a very ...

  14. α-chymotrypsin in water-acetone and water-dimethyl sulfoxide mixtures: Effect of preferential solvation and hydration.

    Science.gov (United States)

    Sirotkin, Vladimir A; Kuchierskaya, Alexandra A

    2017-10-01

    We investigated water/organic solvent sorption and residual enzyme activity to simultaneously monitor preferential solvation/hydration of protein macromolecules in the entire range of water content at 25°C. We applied this approach to estimate protein destabilization/stabilization due to the preferential interactions of bovine pancreatic α-chymotrypsin with water-acetone (moderate-strength H-bond acceptor) and water-DMSO (strong H-bond acceptor) mixtures. There are three concentration regimes for the dried α-chymotrypsin. α-Chymotrypsin is preferentially hydrated at high water content. The residual enzyme activity values are close to 100%. At intermediate water content, the dehydrated α-chymotrypsin has a higher affinity for acetone/DMSO than for water. Residual enzyme activity is minimal in this concentration range. The acetone/DMSO molecules are preferentially excluded from the protein surface at the lowest water content, resulting in preferential hydration. The residual catalytic activity in the water-poor acetone is ∼80%, compared with that observed after incubation in pure water. This effect is very small for the water-poor DMSO. Two different schemes are operative for the hydrated enzyme. At high and intermediate water content, α-chymotrypsin exhibits preferential hydration. However, at intermediate water content, in contrast to the dried enzyme, the initially hydrated α-chymotrypsin possesses increased preferential hydration parameters. At low water content, no residual enzyme activity was observed. Preferential binding of DMSO/acetone to α-chymotrypsin was detected. Our data clearly demonstrate that the hydrogen bond accepting ability of organic solvents and the protein hydration level constitute key factors in determining the stability of protein-water-organic solvent systems. © 2017 Wiley Periodicals, Inc.

  15. Grandparental Child Care in Europe: Evidence for Preferential Investment in More Certain Kin

    Directory of Open Access Journals (Sweden)

    Mirkka Danielsbacka

    2011-01-01

    Full Text Available Theories of kin selection and parental investment predict stronger investment in children and grandchildren by women and maternal kin. Due to paternity uncertainty, parental and grandparental investments along paternal lineages are based on less certain genetic relatedness with the children and grandchildren. Additionally, the hypothesis of preferential investment (Laham, Gonsalkorale, and von Hippel, 2005 predicts investment to vary according to available investment options. Two previous studies have tested this hypothesis with small samples and conflicting results. Using the second wave of the large and multinational Survey of Health, Ageing and Retirement in Europe (SHARE, collected in 2006–07, we study the preferential investment hypothesis in contemporary Europe based on self-reported grandparental provision of child care. We predict that 1 maternal grandmothers provide most care for their grandchildren, followed by maternal grandfathers, paternal grandmothers and last by paternal grandfathers; 2 maternal grandfathers and paternal grandmothers provide equal amounts of care when the latter do not have grandchildren via a daughter; 3 women who have grandchildren via both a daughter and a son will look after the children of the daughter more; and 4 men who have grandchildren via both a daughter and a son will look after the children of the daughter more. Results support all four hypotheses and provide evidence for the continuing effects of paternity uncertainty in contemporary kin behavior.

  16. A conductivity study of preferential solvation of lithium ion in acetonitrile-dimethyl sulfoxide mixtures

    International Nuclear Information System (INIS)

    Mozhzhukhina, Nataliia; Longinotti, M. Paula; Corti, Horacio R.; Calvo, Ernesto J.

    2015-01-01

    The electrical mobility of LiPF 6 in acetonitrile–dimethyl sulfoxide (ACN–DMSO) mixtures, a potential electrolyte in oxygen cathodes of lithium-air batteries, has been studied using a very precise conductance technique, which allowed the determination of the infinite dilution molar conductivity and association constant of the salt in the whole composition range. In the search for preferential Li + ion solvation, we also measured the electrical conductivity of tetrabutylammonium hexafluorophosphate (TBAPF 6 ), a salt formed by a bulky cation, over the same composition range. The results show a qualitative change in the curvature of the LiPF 6 molar conductivity composition dependence for ACN molar fraction (x ACN ) ∼ 0.95, which was not observed for TBAPF 6 . The dependence of the measured Li/Li + couple potential with solvent composition also showed a pronounced change around the same composition. We suggest that these observations can be explained by Li + ion preferential solvation by DMSO in ACN–DMSO mixtures with very low molar fractions of DMSO

  17. Preferential selection based on strategy persistence and memory promotes cooperation in evolutionary prisoner's dilemma games

    Science.gov (United States)

    Liu, Yuanming; Huang, Changwei; Dai, Qionglin

    2018-06-01

    Strategy imitation plays a crucial role in evolutionary dynamics when we investigate the spontaneous emergence of cooperation under the framework of evolutionary game theory. Generally, when an individual updates his strategy, he needs to choose a role model whom he will learn from. In previous studies, individuals choose role models randomly from their neighbors. In recent works, researchers have considered that individuals choose role models according to neighbors' attractiveness characterized by the present network topology or historical payoffs. Here, we associate an individual's attractiveness with the strategy persistence, which characterizes how frequently he changes his strategy. We introduce a preferential parameter α to describe the nonlinear correlation between the selection probability and the strategy persistence and the memory length of individuals M into the evolutionary games. We investigate the effects of α and M on cooperation. Our results show that cooperation could be promoted when α > 0 and at the same time M > 1, which corresponds to the situation that individuals are inclined to select their neighbors with relatively higher persistence levels during the evolution. Moreover, we find that the cooperation level could reach the maximum at an optimal memory length when α > 0. Our work sheds light on how to promote cooperation through preferential selection based on strategy persistence and a limited memory length.

  18. Dependence of crystallite formation and preferential backbone orientations on the side chain pattern in PBDTTPD polymers

    KAUST Repository

    El Labban, Abdulrahman

    2014-11-26

    (Figure Presented) Alkyl substituents appended to the π-conjugated main chain account for the solution-processability and film-forming properties of most π-conjugated polymers for organic electronic device applications, including field-effect transistors (FETs) and bulk-heterojunction (BHJ) solar cells. Beyond film-forming properties, recent work has emphasized the determining role that side-chain substituents play on polymer self-assembly and thin-film nanostructural order, and, in turn, on device performance. However, the factors that determine polymer crystallite orientation in thin-films, implying preferential backbone orientation relative to the device substrate, are a matter of some debate, and these structural changes remain difficult to anticipate. In this report, we show how systematic changes in the side-chain pattern of poly(benzo[1,2-b:4,5-b′]dithiophene-alt-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymers can (i) influence the propensity of the polymer to order in the π-stacking direction, and (ii) direct the preferential orientation of the polymer crystallites in thin films (e.g., "face-on" vs "edge-on"). Oriented crystallites, specifically crystallites that are well-ordered in the π-stacking direction, are believed to be a key contributor to improved thin-film device performance in both FETs and BHJ solar cells.

  19. Simulation study of soil water and heat dynamics at two sites with significant preferential flow

    Science.gov (United States)

    Votrubova, J.; Vogel, T.; Dohnal, M.; Tesar, M.

    2012-04-01

    Numerical models based on two hydraulically contrasting flow domains coupled through a simple transfer formula have become a useful tool for modeling both water flow and associated substance transport in structured soils. A comparative numerical study focused on the preferential flow effects on the soil heat transport is presented. Sites located in two different headwater catchments were included. Experimental catchment Liz is situated in a forested mountain area of Sumava Mts. in the southern part of the Czech Republic (altitude: 830 m, mean annual temperature: 6.3°C, mean annual precipitation: 861 mm). Uhlirska catchment is located in the north-west of the Czech Republic in Jizera Mts. and is currently undergoing reforestation (altitude: 820 m, mean annual temperature: 4.6°C, mean annual precipitation: 1400 mm). Both sites are instrumented for monitoring of the relevant meteorological and hydrological variables, as well as the soil moisture and temperature distribution. Changes of the soil water content and temperature during vegetation season were simulated. Model performance was qualitatively evaluated and shown to replicate the field measurements. The soils' heat budgets and the preferential flow effect thereon was compared and analyzed.

  20. Preferential solvation, ion pairing, and dynamics of concentrated aqueous solutions of divalent metal nitrate salts

    Science.gov (United States)

    Yadav, Sushma; Chandra, Amalendu

    2017-12-01

    We have investigated the characteristics of preferential solvation of ions, structure of solvation shells, ion pairing, and dynamics of aqueous solutions of divalent alkaline-earth metal nitrate salts at varying concentration by means of molecular dynamics simulations. Hydration shell structures and the extent of preferential solvation of the metal and nitrate ions in the solutions are investigated through calculations of radial distribution functions, tetrahedral ordering, and also spatial distribution functions. The Mg2+ ions are found to form solvent separated ion-pairs while the Ca2+ and Sr2+ ions form contact ion pairs with the nitrate ions. These findings are further corroborated by excess coordination numbers calculated through Kirkwood-Buff G factors for different ion-ion and ion-water pairs. The ion-pairing propensity is found to be in the order of Mg(NO3) 2 lead to the presence of substantial dynamical heterogeneity in these solutions of strongly interacting ions. The current study helps us to understand the molecular details of hydration structure, ion pairing, and dynamics of water in the solvation shells and also of ion diffusion in aqueous solutions of divalent metal nitrate salts.

  1. Preferential binding effects on protein structure and dynamics revealed by coarse-grained Monte Carlo simulation

    Science.gov (United States)

    Pandey, R. B.; Jacobs, D. J.; Farmer, B. L.

    2017-05-01

    The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered. While the radius of gyration (Rg) of the protein exhibits a non-monotonic dependence on solvent interaction over a wide range of f within an effective medium, an abrupt collapse in Rg occurs in a narrow range of f when solute molecules rapidly bind to a preferential set of sites on the protein. The structure factor S(q) of the protein with wave vector (q) becomes oscillatory in the collapsed state, which reflects segmental correlations caused by spatial fluctuations in solute-protein binding. Spatial fluctuations in solute binding also modify the effective dimension (D) of the protein in fibrous (D ˜ 1.3), random-coil (D ˜ 1.75), and globular (D ˜ 3) conformational ensembles as the interaction strength increases, which differ from an effective medium with respect to the magnitude of D and the length scale.

  2. Integration of HIV in the Human Genome: Which Sites Are Preferential? A Genetic and Statistical Assessment

    Science.gov (United States)

    Gonçalves, Juliana; Moreira, Elsa; Sequeira, Inês J.; Rodrigues, António S.; Rueff, José; Brás, Aldina

    2016-01-01

    Chromosomal fragile sites (FSs) are loci where gaps and breaks may occur and are preferential integration targets for some viruses, for example, Hepatitis B, Epstein-Barr virus, HPV16, HPV18, and MLV vectors. However, the integration of the human immunodeficiency virus (HIV) in Giemsa bands and in FSs is not yet completely clear. This study aimed to assess the integration preferences of HIV in FSs and in Giemsa bands using an in silico study. HIV integration positions from Jurkat cells were used and two nonparametric tests were applied to compare HIV integration in dark versus light bands and in FS versus non-FS (NFSs). The results show that light bands are preferential targets for integration of HIV-1 in Jurkat cells and also that it integrates with equal intensity in FSs and in NFSs. The data indicates that HIV displays different preferences for FSs compared to other viruses. The aim was to develop and apply an approach to predict the conditions and constraints of HIV insertion in the human genome which seems to adequately complement empirical data. PMID:27294106

  3. Anther-preferential expressing gene PMR is essential for the mitosis of pollen development in rice.

    Science.gov (United States)

    Liu, Yaqin; Xu, Ya; Ling, Sheng; Liu, Shasha; Yao, Jialing

    2017-06-01

    Phenotype identification, expression examination, and function prediction declared that the anther-preferential expressing gene PMR may participate in regulation of male gametophyte development in rice. Male germline development in flowering plants produces the pair of sperm cells for double fertilization and the pollen mitosis is a key process of it. Although the structural features of male gametophyte have been defined, the molecular mechanisms regulating the mitotic cell cycle are not well elucidated in rice. Here, we reported an anther-preferential expressing gene in rice, PMR (Pollen Mitosis Relative), playing an essential role in male gametogenesis. When PMR gene was suppressed via RNAi, the mitosis of microspore was severely damaged, and the plants formed unmatured pollens containing only one or two nucleuses at the anthesis, ultimately leading to serious reduction of pollen fertility and seed-setting. The CRISPR mutants, pmr-1 and pmr-2, both showed the similar defects as the PMR-RNAi lines. Further analysis revealed that PMR together with its co-expressing genes were liable to participate in the regulation of DNA metabolism in the nucleus, and affected the activities of some enzymes related to the cell cycle. We finally discussed that unknown protein PMR contained the PHD, SWIB and Plus-3 domains and they might have coordinating functions in regulation pathway of the pollen mitosis in rice.

  4. Enhanced thermoelectric properties of polycrystalline Bi2Te3 core fibers with preferentially oriented nanosheets

    Directory of Open Access Journals (Sweden)

    Min Sun

    2018-03-01

    Full Text Available Bi2Te3-based materials have been reported to be one of the best room-temperature thermoelectric materials, and it is a challenge to substantially improve their thermoelectric properties. Here novel Bi2Te3 core fibers with borosilicate glass cladding were fabricated utilizing a modified molten core drawing method. The Bi2Te3 core of the fiber was found to consist of hexagonal polycrystalline nanosheets, and polycrystalline nanosheets had a preferential orientation; in other words, the hexagonal Bi2Te3 lamellar cleavage more tended to be parallel to the symmetry axis of the fibers. Compared with a homemade 3-mm-diameter Bi2Te3 rod, the polycrystalline nanosheets’ preferential orientation in the 89-μm-diameter Bi2Te3 core increased its electrical conductivity, but deduced its Seebeck coefficient. The Bi2Te3 core exhibits an ultrahigh ZT of 0.73 at 300 K, which is 232% higher than that of the Bi2Te3 rod. The demonstration of fibers with oriented nano-polycrystalline core and the integration with an efficient fabrication technique will pave the way for the fabrication of high-performance thermoelectric fibers.

  5. Dopamine D2 receptors preferentially regulate the development of light responses of the inner retina

    Science.gov (United States)

    Tian, Ning; Xu, Hong-ping; Wang, Ping

    2014-01-01

    Retinal light responsiveness measured via electroretinography undergoes developmental modulation and is thought to be critically regulated by both visual experience and dopamine. The primary goal of this study is to determine whether the dopamine D2 receptor regulates the visual experience-dependent functional development of the retina. Accordingly, we recorded electroretinograms from wild type mice and mice with a genetic deletion of the gene that encodes the dopamine D2 receptor raised under normal cyclic light conditions and constant darkness. Our results demonstrate that mutation of the dopamine D2 receptors preferentially increases the amplitude of the inner retinal light responses evoked by high intensity light measured as oscillatory potentials in adult mice. During postnatal development, all three major components of electroretinograms, the a-wave, b-wave and oscillatory potentials, increase with age. Comparatively, mutation of the dopamine D2 receptors preferentially reduces the age-dependent increase of b-waves evoked by low intensity light. Light deprivation from birth reduces the amplitude of b-waves and completely diminishes the increased amplitude of oscillatory potentials. Taken together, these results demonstrate that the dopamine D2 receptor plays an important role in the activity-dependent functional development of the mouse retina. PMID:25393815

  6. Preferential solvation of fluorenone and 4-hydroxyfluorenone in binary solvent mixtures

    International Nuclear Information System (INIS)

    Jozefowicz, Marek; Heldt, Janina R.

    2003-01-01

    Preferential solvation of fluorenone and 4-hydroxyfluorenone in binary solvent mixtures has been studied using steady-state spectroscopic measurements. This study concerns the solvent-induced shift of the absorption and fluorescence spectra of both molecules in two solvent mixtures, i.e., cyclohexane-tetrahydrofuran and cyclohexane-ethanol. The first system contains polar solute molecules, fluorenone and 4-hydroxyfluorenone, in a mixture of polar aprotic (tetrahydrofuran) and non-polar (cyclohexane) solvents. In the second solvents mixture, hydrogen bonding with solute molecules (ethanol) may occur. The results of spectroscopic measurements are analysed using theoretical models of Bakshiev, Mazurenko and Suppan which describe preferential solvation phenomena. In the case of cyclohexane-tetrahydrofuran mixtures, the deviation from linearity in the absorption and fluorescence solvatochromic shifts vs. the solution polarity is due to non-specific dipolar solvent-solute interactions. For cyclohexane-ethanol binary mixtures, both non-specific and specific (hydrogen bond and proton-relay tautomerization) interactions contribute to the observed solvatochromism

  7. Dynamic preferential allocation to arbuscular mycorrhizal fungi explains fungal succession and coexistence.

    Science.gov (United States)

    Bachelot, Benedicte; Lee, Charlotte T

    2018-02-01

    Evidence accumulates about the role of arbuscular mycorrhizal (AM) fungi in shaping plant communities, but little is known about the factors determining the biomass and coexistence of several types of AM fungi in a plant community. Here, using a consumer-resource framework that treats the relationship between plants and fungi as simultaneous, reciprocal exploitation, we investigated what patterns of dynamic preferential plant carbon allocation to empirically-defined fungal types (on-going partner choice) would be optimal for plants, and how these patterns depend on successional dynamics. We found that ruderal AM fungi can dominate under low steady-state nutrient availability, and competitor AM fungi can dominate at higher steady-state nutrient availability; these are conditions characteristic of early and late succession, respectively. We also found that dynamic preferential allocation alone can maintain a diversity of mutualists, suggesting that on-going partner choice is a new coexistence mechanism for mutualists. Our model can therefore explain both mutualist coexistence and successional strategy, providing a powerful tool to derive testable predictions. © 2017 by the Ecological Society of America.

  8. Preferential microRNA targeting revealed by in vivo competitive binding and differential Argonaute immunoprecipitation.

    Science.gov (United States)

    Werfel, Stanislas; Leierseder, Simon; Ruprecht, Benjamin; Kuster, Bernhard; Engelhardt, Stefan

    2017-09-29

    MicroRNAs (miRNAs) have been described to simultaneously inhibit hundreds of targets, albeit to a modest extent. It was recently proposed that there could exist more specific, exceptionally strong binding to a subgroup of targets. However, it is unknown, whether this is the case and how such targets can be identified. Using Argonaute2-ribonucleoprotein immunoprecipitation and in vivo competitive binding assays, we demonstrate for miRNAs-21, -199-3p and let-7 exceptional regulation of a subset of targets, which are characterized by preferential miRNA binding. We confirm this finding by analysis of independent quantitative proteome and transcriptome datasets obtained after miRNA silencing. Our data suggest that mammalian miRNA activity is guided by preferential binding of a small set of 3'-untranslated regions, thereby shaping a steep gradient of regulation between potential targets. Our approach can be applied for transcriptome-wide identification of such targets independently of the presence of seed complementary sequences or other predictors. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. Preferential site occupancy of alloying elements in TiAl-based phases

    Energy Technology Data Exchange (ETDEWEB)

    Holec, David, E-mail: david.holec@unileoben.ac.at; Reddy, Rajeev K.; Klein, Thomas; Clemens, Helmut [Department of Physical Metallurgy and Materials Testing, Montanuniversität Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

    2016-05-28

    First principles calculations are used to study the preferential occupation of ternary alloying additions into the binary Ti-Al phases, namely, γ-TiAl, α{sub 2}-Ti{sub 3}Al, β{sub o}-TiAl, and B19-TiAl. While the early transition metals (TMs, group IVB, VB, and VIB elements) prefer to substitute for Ti atoms in the γ-, α{sub 2}-, and B19-phases, they preferentially occupy Al sites in the β{sub o}-TiAl. Si is, in this context, an anomaly, as it prefers to sit on the Al sublattice for all four phases. B and C are shown to prefer octahedral Ti-rich interstitial positions instead of substitutional incorporation. The site preference energy is linked with the alloying-induced changes of energy of formation, hence alloying-related (de)stabilisation of the phases. We further show that the phase-stabilisation effect of early TMs on β{sub o}-phase has a different origin depending on their valency. Finally, an extensive comparison of our predictions with available theoretical and experimental data (which is, however, limited mostly to the γ-phase) shows a consistent picture.

  10. The Dynamics of Power laws: Fitness and Aging in Preferential Attachment Trees

    Science.gov (United States)

    Garavaglia, Alessandro; van der Hofstad, Remco; Woeginger, Gerhard

    2017-09-01

    Continuous-time branching processes describe the evolution of a population whose individuals generate a random number of children according to a birth process. Such branching processes can be used to understand preferential attachment models in which the birth rates are linear functions. We are motivated by citation networks, where power-law citation counts are observed as well as aging in the citation patterns. To model this, we introduce fitness and age-dependence in these birth processes. The multiplicative fitness moderates the rate at which children are born, while the aging is integrable, so that individuals receives a finite number of children in their lifetime. We show the existence of a limiting degree distribution for such processes. In the preferential attachment case, where fitness and aging are absent, this limiting degree distribution is known to have power-law tails. We show that the limiting degree distribution has exponential tails for bounded fitnesses in the presence of integrable aging, while the power-law tail is restored when integrable aging is combined with fitness with unbounded support with at most exponential tails. In the absence of integrable aging, such processes are explosive.

  11. Preferential repair of nuclear matrix associated DNA in xeroderma pigmentosum complementation group C

    International Nuclear Information System (INIS)

    Mullenders, L.H.F.; Kesteren, A.C. van; Bussmann, C.J.M.; Zeeland, A.A. van; Natarajan, A.T.

    1984-01-01

    The distribution of ultraviolet-induced DNA repair patches in the genome of xeroderma pigmentosum cells of complementation group C was investigated by determining the molecular weight distribution of repair labeled DNA and prelabeled DNA in alkaline sucrose gradients after treatment with the dimer-specific endonuclease V of bacteriophage T 4 . The results suggest that DNA-repair synthesis in xeroderma pigmentosum cells of complementation group C occurs in localized regions of the genome. Analysis of the spatial distribution of ultraviolet-induced repair patches in DNA loops attached to the nuclear matrix revealed that in xeroderma pigmentosum cells of complementation group C repair patches are preferentially situated near the attachment sites of DNA loops at the nuclear matrix. In normal human fibroblasts the authors observed no enrichment of repair-labeled DNA at the nuclear matrix and repair patches appeared to be distributed randomly along the DNA loops. The enrichment of repair-labeled DNA at the nuclear matrix in xeroderma pigmentosum cells of complementation group C may indicate that the residual DNA-repair synthesis in these cells occurs preferentially in regions of the genome. (Auth.)

  12. Preferential Cyclooxygenase 2 Inhibitors as a Nonhormonal Method of Emergency Contraception: A Look at the Evidence.

    Science.gov (United States)

    Weiss, Erich A; Gandhi, Mona

    2016-04-01

    To review the literature surrounding the use of preferential cyclooxygenase 2 (COX-2) inhibitors as an alternative form of emergency contraception. MEDLINE (1950 to February 2014) was searched using the key words cyclooxygenase or COX-2 combined with contraception, emergency contraception, or ovulation. Results were limited to randomized control trials, controlled clinical trials, and clinical trials. Human trials that measured the effects of COX inhibition on female reproductive potential were included for review. The effects of the COX-2 inhibitors rofecoxib, celecoxib, and meloxicam were evaluated in 6 trials. Each of which was small in scope, enrolled women of variable fertility status, used different dosing regimens, included multiple end points, and had variable results. Insufficient evidence exists to fully support the use of preferential COX-2 inhibitors as a form of emergency contraception. Although all trials resulted in a decrease in ovulatory cycles, outcomes varied between dosing strategies and agents used. A lack of homogeneity in these studies makes comparisons difficult. However, success of meloxicam in multiple trials warrants further study. Larger human trials are necessary before the clinical utility of this method of emergency contraception can be fully appreciated. © The Author(s) 2014.

  13. A cocaine context renews drug seeking preferentially in a subset of individuals.

    Science.gov (United States)

    Saunders, Benjamin T; O'Donnell, Elizabeth G; Aurbach, Elyse L; Robinson, Terry E

    2014-11-01

    Addiction is characterized by a high propensity for relapse, in part because cues associated with drugs can acquire Pavlovian incentive motivational properties, and acting as incentive stimuli, such cues can instigate and invigorate drug-seeking behavior. There is, however, considerable individual variation in the propensity to attribute incentive salience to reward cues. Discrete and localizable reward cues act as much more effective incentive stimuli in some rats ('sign-trackers', STs), than others ('goal-trackers', GTs). We asked whether similar individual variation exists for contextual cues associated with cocaine. Cocaine context conditioned motivation was quantified in two ways: (1) the ability of a cocaine context to evoke conditioned hyperactivity and (2) the ability of a context in which cocaine was previously self-administered to renew cocaine-seeking behavior. Finally, we assessed the effects of intra-accumbens core flupenthixol, a nonselective dopamine receptor antagonist, on context renewal. In contrast to studies using discrete cues, a cocaine context spurred greater conditioned hyperactivity, and more robustly renewed extinguished cocaine seeking in GTs than STs. In addition, cocaine context renewal was blocked by antagonism of dopamine receptors in the accumbens core. Thus, contextual cues associated with cocaine preferentially acquire motivational control over behavior in different individuals than do discrete cues, and in these individuals the ability of a cocaine context to create conditioned motivation for cocaine requires dopamine in the core of the nucleus accumbens. We speculate that different individuals may be preferentially sensitive to different 'triggers' of relapse.

  14. Quantifying Preferential Flow and Seasonal Storage in an Unsaturated Fracture-Facial Domain

    Science.gov (United States)

    Nimmo, J. R.; Malek-Mohammadi, S.

    2012-12-01

    Preferential flow through deep unsaturated zones of fractured rock is hydrologically important to a variety of contaminant transport and water-resource issues. The unsaturated zone of the English Chalk Aquifer provides an important opportunity for a case study of unsaturated preferential flow in isolation from other flow modes. The chalk matrix has low hydraulic conductivity and stays saturated, owing to its fine uniform pores and the wet climate of the region. Therefore the substantial fluxes observed in the unsaturated chalk must be within fractures and interact minimally with matrix material. Price et al. [2000] showed that irregularities on fracture surfaces provide a significant storage capacity in the chalk unsaturated zone, likely accounting for volumes of water required to explain unexpected dry-season water-table stability during substantial continuing streamflow observed by Lewis et al. [1993] In this presentation we discuss and quantify the dynamics of replenishment and drainage of this unsaturated zone fracture-face storage domain using a modification of the source-responsive model of Nimmo [2010]. This model explains the processes in terms of two interacting flow regimes: a film or rivulet preferential flow regime on rough fracture faces, active on an individual-storm timescale, and a regime of adsorptive and surface-tension influences, resembling traditional diffuse formulations of unsaturated flow, effective mainly on a seasonal timescale. The modified model identifies hydraulic parameters for an unsaturated fracture-facial domain lining the fractures. Besides helping to quantify the unsaturated zone storage described by Price et al., these results highlight the importance of research on the topic of unsaturated-flow relations within a near-fracture-surface domain. This model can also facilitate understanding of mechanisms for reinitiation of preferential flow after temporary cessation, which is important in multi-year preferential flow through deep

  15. Growing electronic documents created by researchers

    Directory of Open Access Journals (Sweden)

    Monika Weiss

    2017-05-01

    Full Text Available In the contemporary world technology is an indispensable element, both in personal and professional sphere. Despite the fact, that we do not attach significance to it in our everyday lives, the technological development engulfed us and still reminds us about that. In the face of dynamically growing digitization there occurred a new form of document – an electronic document. The study concerns the growing electronic documentation among researchers working at the Nicolaus Copernicus University in Toruń. The analysis of surveys and interviews resulted in thesis, that researchers use e-document more frequently than analog documentation. Flexibility and accessibility of this type of documents become a problem in personal papers which will be archived in the future – maybe in most part in the form of electronic documentation.

  16. Petroleum demand continues to grow but slowly

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    While it is always entertaining and intellectually stimulating to look at all the marvelous technological alternatives just around the corner for transport, the transport task in Australia continues to grow and so does petroleum consumption. Australia presently consumes more than 750,000 barrels per day of petroleum products. Latest figures are given for petroleum consumption up to the end of August 1998. They indicate that total demand for petrol has continued to grow, but very slowly. Growth in 1997-1998 compared with 1996-1997 was only 0.3%. This trend for very low growth has been continued into July and August, perhaps indicative of a slow down in the economy

  17. Shape of the growing front of biofilms

    Science.gov (United States)

    Wang, Xin; Stone, Howard A.; Golestanian, Ramin

    2017-12-01

    The spatial organization of bacteria in dense biofilms is key to their collective behaviour, and understanding it will be important for medical and technological applications. Here we study the morphology of a compact biofilm that undergoes unidirectional growth, and determine the condition for the stability of the growing interface as a function of the nutrient concentration and mechanical tension. Our study suggests that transient behaviour may play an important role in shaping the structure of a biofilm.

  18. Australia: A Growing Market for Asean Exports?

    OpenAIRE

    Tongzon, J.L.

    1988-01-01

    Much has been written regarding South East Asian countries as growing markets for Australian exports particularly in the past decade. But nothing so far has been done to examine whether ASEAN exports have also experienced some redirection towards the Australian market. The findings confirm our a priori expectations: no significant general reorientation was observed for the ASEAN group of countries, and ASEAN’s country bias declined over the period under study. This is in contrast to the Austr...

  19. Growing Role of Retail in Distribution Channels

    OpenAIRE

    Ishak Mesic

    2011-01-01

    This article aims to demonstrate the growing role of retail trade (retail) in the channels of distribution of goods both in domestic and international markets. Technical-technological development has provided great opportunities for all production of material goods, so that the focus of problem in the economic possibilities of playing shifted from production to sales opportunities, or consumption. The ultimate consumers and their needs and requirements have become a central area of study, bas...

  20. GRoW Buffalo Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Bohm, Martha [Univ. at Buffalo, NY (United States)

    2016-04-17

    This document provides final reporting on the GRoW Home, University at Buffalo's entry to the 2015 Solar Decathlon competition in Irvine, CA. The report summarizes fundraising efforts, documents media outreach, lists online presence, analyzes the organizer's communication, describes post-competition life of the house and future employment plans for student team members. Last, it suggests improvements for future decathlons.

  1. Controlled surface chemistry of diamond/β-SiC composite films for preferential protein adsorption.

    Science.gov (United States)

    Wang, Tao; Handschuh-Wang, Stephan; Yang, Yang; Zhuang, Hao; Schlemper, Christoph; Wesner, Daniel; Schönherr, Holger; Zhang, Wenjun; Jiang, Xin

    2014-02-04

    Diamond and SiC both process extraordinary biocompatible, electronic, and chemical properties. A combination of diamond and SiC may lead to highly stable materials, e.g., for implants or biosensors with excellent sensing properties. Here we report on the controllable surface chemistry of diamond/β-SiC composite films and its effect on protein adsorption. For systematic and high-throughput investigations, novel diamond/β-SiC composite films with gradient composition have been synthesized using the hot filament chemical vapor deposition (HFCVD) technique. As revealed by scanning electron microscopy (SEM), the diamond/β-SiC ratio of the composite films shows a continuous change from pure diamond to β-SiC over a length of ∼ 10 mm on the surface. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to unveil the surface termination of chemically oxidized and hydrogen treated surfaces. The surface chemistry of the composite films was found to depend on diamond/β-SiC ratio and the surface treatment. As observed by confocal fluorescence microscopy, albumin and fibrinogen were preferentially adsorbed from buffer: after surface oxidation, the proteins preferred to adsorb on diamond rather than on β-SiC, resulting in an increasing amount of proteins adsorbed to the gradient surfaces with increasing diamond/β-SiC ratio. By contrast, for hydrogen-treated surfaces, the proteins preferentially adsorbed on β-SiC, leading to a decreasing amount of albumin adsorbed on the gradient surfaces with increasing diamond/β-SiC ratio. The mechanism of preferential protein adsorption is discussed by considering the hydrogen bonding of the water self-association network to OH-terminated surfaces and the change of the polar surface energy component, which was determined according to the van Oss method. These results suggest that the diamond/β-SiC gradient film can be a promising material for biomedical applications which

  2. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Directory of Open Access Journals (Sweden)

    M. O. Cuthbert

    2013-03-01

    Full Text Available Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is presented and tested using a range of numerical models, including a modified soil moisture balance model (SMBM for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via preferential flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in preferential flow pathways due to seasonal ploughing of the topsoil and to a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010 is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  3. The effect of trees on preferential flow and soil infiltrability in an agroforestry parkland in semiarid Burkina Faso.

    Science.gov (United States)

    Bargués Tobella, A; Reese, H; Almaw, A; Bayala, J; Malmer, A; Laudon, H; Ilstedt, U

    2014-04-01

    Water scarcity constrains the livelihoods of millions of people in tropical drylands. Tree planting in these environments is generally discouraged due to the large water consumption by trees, but this view may neglect their potential positive impacts on water availability. The effect of trees on soil hydraulic properties linked to groundwater recharge is poorly understood. In this study, we performed 18 rainfall simulations and tracer experiments in an agroforestry parkland in Burkina Faso to investigate the effect of trees and associated termite mounds on soil infiltrability and preferential flow. The sampling points were distributed in transects each consisting of three positions: (i) under a single tree, (ii) in the middle of an open area, and (iii) under a tree associated with a termite mound. The degree of preferential flow was quantified through parameters based on the dye infiltration patterns, which were analyzed using image analysis of photographs. Our results show that the degree of preferential flow was highest under trees associated with termite mounds, intermediate under single trees, and minimal in the open areas. Tree density also had an influence on the degree of preferential flow, with small open areas having more preferential flow than large ones. Soil infiltrability was higher under single trees than in the open areas or under trees associated with a termite mound. The findings from this study demonstrate that trees have a positive impact on soil hydraulic properties influencing groundwater recharge, and thus such effects must be considered when evaluating the impact of trees on water resources in drylands. Trees in dryland landscapes increase soil infiltrability and preferential flow Termite mounds in association with trees further enhance preferential flow.

  4. Exposure to vibrations in wine growing

    Directory of Open Access Journals (Sweden)

    Domenico Pessina

    2013-09-01

    Full Text Available Apart the winter period, the activity in specialized agricultural cultivations (i.e. wine- and fruit-growing is distributed for a long period of the year. Some tasks, such as pesticide distribution, are repeated several times during the growing season. On the other hand, mechanization is one of the pillars on which is based the modern agriculture management. As a consequence, in wine growing the tractor driver has to be considered a worker potentially subjected to high level of vibrations, due to the poor machinery conditions often encountered, and sometimes to the rough soil surface of the vineyard combined with the high travelling speed adopted in carrying out many operations. About vibrations, the Italian Decree 81/08 basically refers to the European Directive 2002/44/CE, that provides some very strict limits of exposure, both for whole body and hand-arm districts. In Oltrepo pavese, a large hilly area located the south part of the Pavia province (Lombardy - Italy wine growing is the main agricultural activity; for this reason, a detailed survey on the vibration levels recorded at the tractor driver’s seat was carried out, in order to ascertain the real risk to which the operators are exposed. The activity in wine growing has been classified into 6 groups of similar tasks, as follows: 1. canopy management: pruning, trimming, binding, stripping, etc.; 2. soil management: harrowing, hoeing, subsoiling etc.; 3. inter-row management: chopping of pruning , pinching, grass mowing, etc.; 4. crop protection: pesticides and fungicides distribution, sulfidation, foliar fertilization, etc.; 5. grape harvesting: manual or mechanical; 6. transport: from the vineyard to the cellar. For each group of tasks, the vibration levels on 3 the traditional axes (x, y and z were recorded, and then an exposure time was calculated for each of them, in order to ascertain the risk level in comparison to what provided by the dedicated standard. Finally, a detailed

  5. Receptor-isoform-selective insulin analogues give tissue-preferential effects

    DEFF Research Database (Denmark)

    Vienberg, Sara Gry; Bouman, Stephan D; Sørensen, Heidi

    2011-01-01

    The relative expression patterns of the two IR (insulin receptor) isoforms, +/- exon 11 (IR-B/IR-A respectively), are tissue-dependent. Therefore we have developed insulin analogues with different binding affinities for the two isoforms to test whether tissue-preferential biological effects can...... be attained. In rats and mice, IR-B is the most prominent isoform in the liver (> 95%) and fat (> 90%), whereas in muscles IR-A is the dominant isoform (> 95%). As a consequence, the insulin analogue INS-A, which has a higher relative affinity for human IR-A, had a higher relative potency [compared with HI...... (human insulin)] for glycogen synthesis in rat muscle strips (26%) than for glycogen accumulation in rat hepatocytes (5%) and for lipogenesis in rat adipocytes (4%). In contrast, the INS-B analogue, which has an increased affinity for human IR-B, had higher relative potencies (compared with HI...

  6. Preferential Production and Transport of Grass-Derived Pyrogenic Carbon in NE-Australian Savanna Ecosystems

    Directory of Open Access Journals (Sweden)

    Gustavo Saiz

    2018-01-01

    Full Text Available Understanding the main factors driving fire regimes in grasslands and savannas is critical to better manage their biodiversity and functions. Moreover, improving our knowledge on pyrogenic carbon (PyC dynamics, including formation, transport and deposition, is fundamental to better understand a significant slow-cycling component of the global carbon cycle, particularly as these ecosystems account for a substantial proportion of the area globally burnt. However, a thorough assessment of past fire regimes in grass-dominated ecosystems is problematic due to challenges in interpreting the charcoal record of sediments. It is therefore critical to adopt appropriate sampling and analytical methods to allow the acquisition of reliable data and information on savanna fire dynamics. This study uses hydrogen pyrolysis (HyPy to quantify PyC abundance and stable isotope composition (δ13C in recent sediments across 38 micro-catchments covering a wide range of mixed C3/C4 vegetation in north Queensland, Australia. We exploited the contrasting δ13C values of grasses (i.e., C4; δ13C > −15‰ and woody vegetation (i.e., C3; δ13C < −24‰ to assess the preferential production and transport of grass-derived PyC in savanna ecosystems. Analyses were conducted on bulk and size-fractionated samples to determine the fractions into which PyC preferentially accumulates. Our data show that the δ13C value of PyC in the sediments is decoupled from the δ13C value of total organic carbon, which suggests that a significant component of PyC may be derived from incomplete grass combustion, even when the proportion of C4 grass biomass in the catchment was relatively small. Furthermore, we conducted 16 experimental burns that indicate that there is a comminution of PyC produced in-situ to smaller particles, which facilitates the transport of this material, potentially affecting its preservation potential. Savanna fires preferentially burn the grass understory rather than

  7. Schemes for aggregating preferential tariffs in agriculture,export volume effects and African LDCs

    DEFF Research Database (Denmark)

    Yu, Wusheng

    Trade-weighted aggregated tariffs (TWPT) are often used in analyzing the issues of erosion of non-reciprocal preferences. This paper argues that commonly used TWPTs under-estimate the true protection on imports originated from preference-receiving countries, including LDCs. When used in numerical...... simulations of preference erosion and expansion scenarios, the TWPTs tend to incorrectly downplay preference erosion effect of MFN tariff cuts, and understate the export promotion effect of expanding preferences. In light of these claims, an alternative aggregation scheme is developed to calculate aggregated...... preferential tariffs imposed by a number of developed countries on African LDCs. These are shown to be higher than the TWPTs aggregated from the same disaggregated tariff data set. Numerical simulations conducted with the two sets of aggregated tariffs confirm the two claims and suggest that TWPTs may lead...

  8. Nanofibrillar scaffolds induce preferential activation of Rho GTPases in cerebral cortical astrocytes

    Science.gov (United States)

    Tiryaki, Volkan Mujdat; Ayres, Virginia M; Khan, Adeel A; Ahmed, Ijaz; Shreiber, David I; Meiners, Sally

    2012-01-01

    Cerebral cortical astrocyte responses to polyamide nanofibrillar scaffolds versus poly-L-lysine (PLL)-functionalized planar glass, unfunctionalized planar Aclar coverslips, and PLL-functionalized planar Aclar surfaces were investigated by atomic force microscopy and immunocytochemistry. The physical properties of the cell culture environments were evaluated using contact angle and surface roughness measurements and compared. Astrocyte morphological responses, including filopodia, lamellipodia, and stress fiber formation, and stellation were imaged using atomic force microscopy and phalloidin staining for F-actin. Activation of the corresponding Rho GTPase regulators was investigated using immunolabeling with Cdc42, Rac1, and RhoA. Astrocytes cultured on the nanofibrillar scaffolds showed a unique response that included stellation, cell–cell interactions by stellate processes, and evidence of depression of RhoA. The results support the hypothesis that the extracellular environment can trigger preferential activation of members of the Rho GTPase family, with demonstrable morphological consequences for cerebral cortical astrocytes. PMID:22915841

  9. Separation of enantiomers by continuous preferential crystallization: Experimental realization using a coupled crystallizer configuration

    DEFF Research Database (Denmark)

    Chaaban, Joussef Hussein; Dam-Johansen, Kim; Kiil, Søren

    2013-01-01

    The experimental realization of a continuous preferential crystallization process, consisting of two mixed-flow crystallizers coupled via crystal-free liquid exchange streams and with only the liquid phases operating continuously, is addressed. Experiments in triplicate, using the conglomerate....... Successful enantioseparation by crystal growth, with the repeatability being within ±10% deviation, was obtained. However, slow crystal growth, due to a low surface integration rate, led to a negligible consumption of the desired enantiomer added in the feed solution, resulting in low productivities....... Productivities, yields, and purities of solid products were influenced by the morphological differences in the seed crystals. Due to irregularly shaped seed crystals, increase in the productivities and yields were achieved in the L-Tank. Lower purities of solid products from the L-Tank compared to purities...

  10. The preferential orientation and lattice misfit of the directionally solidified Fe-Al-Ta eutectic composite

    Science.gov (United States)

    Cui, Chunjuan; Wang, Pei; Yang, Meng; Wen, Yagang; Ren, Chiqiang; Wang, Songyuan

    2018-01-01

    Fe-Al intermetallic compound has been paid more attentions recently in many fields such as aeronautic, aerospace, automobile, energy and chemical engineering, and so on. In this paper Fe-Al-Ta eutectic was prepared by a modified Bridgman directional solidification technique, and it is found that microstructure of the Fe-Al-Ta eutectic alloy transforms from the broken-lamellar eutectic to cellular eutectic with the increase of the solidification rate. In the cellular eutectic structure, the fibers are parallel to each other within the same grain, but some fibers are deviated from the original orientation at the grain boundaries. To study the crystallographic orientation relationship (OR) between the two phases, the preferential orientation of the Fe-Al-Ta eutectic alloy at the different solidification rates was studied by Selected Area Electron Diffraction (SAED). Moreover, the lattice misfit between Fe2Ta(Al) Laves phase and Fe(Al,Ta) matrix phase was calculated.

  11. Stratification of TAD boundaries reveals preferential insulation of super-enhancers by strong boundaries.

    Science.gov (United States)

    Gong, Yixiao; Lazaris, Charalampos; Sakellaropoulos, Theodore; Lozano, Aurelie; Kambadur, Prabhanjan; Ntziachristos, Panagiotis; Aifantis, Iannis; Tsirigos, Aristotelis

    2018-02-07

    The metazoan genome is compartmentalized in areas of highly interacting chromatin known as topologically associating domains (TADs). TADs are demarcated by boundaries mostly conserved across cell types and even across species. However, a genome-wide characterization of TAD boundary strength in mammals is still lacking. In this study, we first use fused two-dimensional lasso as a machine learning method to improve Hi-C contact matrix reproducibility, and, subsequently, we categorize TAD boundaries based on their insulation score. We demonstrate that higher TAD boundary insulation scores are associated with elevated CTCF levels and that they may differ across cell types. Intriguingly, we observe that super-enhancers are preferentially insulated by strong boundaries. Furthermore, we demonstrate that strong TAD boundaries and super-enhancer elements are frequently co-duplicated in cancer patients. Taken together, our findings suggest that super-enhancers insulated by strong TAD boundaries may be exploited, as a functional unit, by cancer cells to promote oncogenesis.

  12. Preferential Hyperacuity Perimeter (PreView PHP) for detecting choroidal neovascularization study.

    Science.gov (United States)

    Alster, Yair; Bressler, Neil M; Bressler, Susan B; Brimacombe, Judith A; Crompton, R Michael; Duh, Yi-Jing; Gabel, Veit-Peter; Heier, Jeffrey S; Ip, Michael S; Loewenstein, Anat; Packo, Kirk H; Stur, Michael; Toaff, Techiya

    2005-10-01

    To assess the ability of the Preferential Hyperacuity Perimeter (PreView PHP; Carl Zeiss Meditec, Dublin, CA) to detect recent-onset choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) and to differentiate it from an intermediate stage of AMD. Prospective, comparative, concurrent, nonrandomized, multicenter study. Eligible participants' study eyes had a corrected visual acuity of 20/160 or better and either untreated CNV from AMD diagnosed within the last 60 days or an intermediate stage of AMD. After obtaining consent, visual acuity with habitual correction, masked PHP testing, stereoscopic color fundus photography, and fluorescein angiography were performed. Photographs and angiograms were evaluated by graders masked to diagnosis and PHP results. The reading center's diagnosis determined if the patient was categorized as having intermediate AMD or neovascular AMD. A successful study outcome was defined a priori as a sensitivity of at least 80% and a specificity of at least 80%. Of 185 patients who gave consent to be enrolled, 11 (6%) had PHP results judged to be unreliable. An additional 52 were not included because they did not meet all eligibility criteria. Of the remaining 122 patients, 57 had an intermediate stage of AMD and 65 had neovascular AMD. The sensitivity to detect newly diagnosed CNV using PHP testing was 82% (95% confidence interval [CI], 70%-90%). The specificity to differentiate newly diagnosed CNV from the intermediate stage of AMD using PHP testing was 88% (95% CI, 76%-95%). Preferential Hyperacuity Perimeter testing can detect recent-onset CNV resulting from AMD and can differentiate it from an intermediate stage of AMD with high sensitivity and specificity. These data suggest that monitoring with PHP should detect most cases of CNV of recent onset with few false-positive results at a stage when treatment usually would be beneficial. Thus, this monitoring should be considered in the management of the

  13. Imaging Preferential Flow Pathways of Contaminants from Passive Acid Mine Drainage Mitigation Sites Using Electrical Resistivity

    Science.gov (United States)

    Kelley, N.; Mount, G.; Terry, N.; Herndon, E.; Singer, D. M.

    2017-12-01

    The Critical Zone represents the surficial and shallow layer of rock, air, water, and soil where most interactions between living organisms and the Earth occur. Acid mine drainage (AMD) resulting from coal extraction can influence both biological and geochemical processes across this zone. Conservative estimates suggest that more than 300 million gallons of AMD are released daily, making this acidic solution of water and contaminants a common issue in areas with legacy or current coal extraction. Electrical resistivity imaging (ERI) provides a rapid and minimally invasive method to identify and monitor contaminant pathways from AMD remediation systems in the subsurface of the Critical Zone. The technique yields spatially continuous data of subsurface resistivity that can be inverted to determine electrical conductivity as a function of depth. Since elevated concentrations of heavy metals can directly influence soil conductivity, ERI data can be used to trace the flow pathways or perhaps unknown mine conduits and transport of heavy metals through the subsurface near acid mine drainage sources. This study aims to examine preferential contaminant migration from those sources through substrate pores, fractures, and shallow mine workings in the near subsurface surrounding AMD sites in eastern Ohio and western Pennsylvania. We utilize time lapse ERI measures during different hydrologic conditions to better understand the variability of preferential flow pathways in relation to changes in stage and discharge within the remediation systems. To confirm ERI findings, and provide constraint to geochemical reactions occurring in the shallow subsurface, we conducted Inductively Coupled Plasma (ICP) spectrometry analysis of groundwater samples from boreholes along the survey transects. Through these combined methods, we can provide insight into the ability of engineered systems to contain and isolate metals in passive acid mine drainage treatment systems.

  14. Liposomal Fasudil, a Rho-Kinase Inhibitor, for Prolonged Pulmonary Preferential Vasodilation in Pulmonary Arterial Hypertension

    Science.gov (United States)

    Gupta, Vivek; Gupta, Nilesh; Shaik, Imam H.; Mehvar, Reza; McMurtry, Ivan F.; Oka, Masahiko; Nozik-Grayck, Eva; Komatsu, Masanobu; Ahsan, Fakhrul

    2013-01-01

    Current pharmacological interventions for pulmonary arterial hypertension (PAH) require continuous infusions, multiple inhalations, or oral administration of drugs that act on various pathways involved in the pathogenesis of PAH. However, invasive methods of administration, short duration of action, and lack of pulmonary selectivity result in noncompliance and poor patient outcomes. In this study, we tested the hypothesis that encapsulation of an investigational anti-PAH molecule fasudil (HA-1077), a Rho-kinase inhibitor, into liposomal vesicles results in prolonged vasodilation in distal pulmonary arterioles. Liposomes were prepared by hydration and extrusion method and fasudil was loaded by ammonium sulfate-induced transmembrane electrochemical gradient. Liposomes were then characterized for various physicochemical properties. Optimized formulations were tested for pulmonary absorption and their pharmacological efficacy in a monocrotaline (MCT) induced rat model of PAH. The entrapment efficiency of optimized liposomal fasudil formulations was between 68.1±0.8% and 73.6±2.3%, and the cumulative release at 37°C was 98–99% over a period of 5 days. Compared to intravenous (IV) fasudil, a ~10 fold increase in the terminal plasma half-life was observed when liposomal fasudil was administered as aerosols. The t1/2 of IV fasudil was 0.39±0.12 h. and when given as liposomes via pulmonary route, the t1/2 extended to 4.71±0.72 h. One h after intratracheal instillation of liposomal fasudil, mean pulmonary arterial pressure (MPAP) was reduced by 37.6±5.7% and continued to decrease for about 3 h, suggesting that liposomal formulations produced pulmonary preferential vasodilation in MCT induced PAH rats. Overall, this study established the proof-of-principle that aerosolized liposomal fasudil is a feasible option for a non-invasive, controlled release and pulmonary preferential treatment of PAH. PMID:23353807

  15. Spatial information is preferentially processed by the distal part of CA3: implication for memory retrieval.

    Science.gov (United States)

    Flasbeck, Vera; Atucha, Erika; Nakamura, Nozomu H; Yoshida, Motoharu; Sauvage, Magdalena M

    2018-07-16

    For the past decades, CA3 was considered as a single functional entity. However, strong differences between the proximal (close to the dentate gyrus) and the distal (close to CA2) parts of CA3 in terms of connectivity patterns, gene expression and electrophysiological properties suggest that it is not the case. We recently showed that proximal CA3 (together with distal CA1) preferentially deals with non-spatial information [1]. In contrast to proximal CA3, distal CA3 mainly receives and predominantly projects to spatially tuned areas. Here, we tested if distal CA3 preferentially processes spatial information, which would suggest a segregation of the spatial information along the proximodistal axis of CA3. We used a high-resolution imaging technique based on the detection of the expression of the immediate-early gene Arc, commonly used to map activity in the medial temporal lobe. We showed that distal CA3 is strongly recruited in a newly designed delayed nonmatching-to-location task with high memory demands in rats, while proximal CA3 is not. These results indicate a functional segregation of CA3 that mirrors the one reported in CA1, and suggest the existence of a distal CA3- proximal CA1 spatial subnetwork. These findings bring further evidence for the existence of 'specialized' spatial and non-spatial subnetworks segregated along the proximodistal axis of the hippocampus and put forward the 'segregated' view of information processing in the hippocampus as a reasonable alternative to the well-accepted 'integrated' view, according to which spatial and non-spatial information are systematically integrated in the hippocampus to form episodic memory. Copyright © 2018. Published by Elsevier B.V.

  16. Preferential localization of 3H-pentosanpolysulphate to the urinary tract in rats

    International Nuclear Information System (INIS)

    Odlind, B.; Tengblad, A.; Dencker, L.

    1987-01-01

    Endogenous glycosaminoglycans probably have a protective effect in the urinary tract, e.g. against stone formation. The synthetic sulphated polysaccharide pentosanpolysulphate (PPS) has been suggested to exert a similar protective effect e.g. by inhibition of crystallization and bacterial anti-adhesion. We have studied the distribution in rats of tritium-labelled PPS. Chromatography showed this material to contain two distinct peaks with approximate molecular weight around 2.700 (60-70%) and 1.000 (30-40%) daltons. PPS was administered orally and intravenously (5 mg/kg b.wt) to Sprague-Dawley rats, which were killed 1 and 4 hours later, respectively, and subjected to whole-body autoradiography. Autoradiograms of sections from intravenously injected rats showed an extensive distribution of radioactivity in the whole animal, with a notable labelling of connective tissues, while bone and cartilage had low activity. There was upper intestine activity, suggesting some hepatic excretion. The most conspicuous finding, however, was the high concentration in urine and a preferential localization of activity corresponding to the lining of the urinary tract (pelvis, ureter, and bladder). The distribution was similar, but the activity lower after oral administration. After vigorous rinsing, with saline, the radioactivity was still retained in the bladder wall. High amount of radioactivity could be rinsed off by 0.5 M saline. Chromatography of the rinsing solution showed presence of both fractions of PPS previously found in the injection solution. No other peak of activity was found. Since PPS of molecular weight 2.700 and 1.000 is preferentially located to the surface epithelium of the urinary tract in rats, the effects of PPS in urinary tract diseases could depend on surface coating of the epithelium and/or urinary concentrations of PPS. (EG)

  17. Thin film growing by the laser ablation technique: possibilities for growing of dosimetric materials

    International Nuclear Information System (INIS)

    Rojas R, E.M.; Melo M, M.; Enriquez Z, E.; Fernandez G, M.; Haro P, E.; Hernandez P, J.L.

    2005-01-01

    In this talk we will present the basics about the laser ablation technique and how it is used for thin film growing, either as a single film or a stack of thin films, as well as some methods to characterize in real time the film thickness. Finally, we will discuss the possibilities of using laser ablation for growing thin films with applications to dosimetry. (Author)

  18. Impact of preferential sampling on exposure prediction and health effect inference in the context of air pollution epidemiology.

    Science.gov (United States)

    Lee, A; Szpiro, A; Kim, S Y; Sheppard, L

    2015-06-01

    Preferential sampling has been defined in the context of geostatistical modeling as the dependence between the sampling locations and the process that describes the spatial structure of the data. It can occur when networks are designed to find high values. For example, in networks based on the U.S. Clean Air Act monitors are sited to determine whether air quality standards are exceeded. We study the impact of the design of monitor networks in the context of air pollution epidemiology studies. The effect of preferential sampling has been illustrated in the literature by highlighting its impact on spatial predictions. In this paper, we use these predictions as input in a second stage analysis, and we assess how they affect health effect inference. Our work is motivated by data from two United States regulatory networks and health data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. The two networks were designed to monitor air pollution in urban and rural areas respectively, and we found that the health analysis results based on the two networks can lead to different scientific conclusions. We use preferential sampling to gain insight into these differences. We designed a simulation study, and found that the validity and reliability of the health effect estimate can be greatly affected by how we sample the monitor locations. To better understand its effect on second stage inference, we identify two components of preferential sampling that shed light on how preferential sampling alters the properties of the health effect estimate.

  19. The effect of trees on preferential flow and soil infiltrability in an agroforestry parkland in semiarid Burkina Faso

    Science.gov (United States)

    Bargués Tobella, A.; Reese, H.; Almaw, A.; Bayala, J.; Malmer, A.; Laudon, H.; Ilstedt, U.

    2014-04-01

    Water scarcity constrains the livelihoods of millions of people in tropical drylands. Tree planting in these environments is generally discouraged due to the large water consumption by trees, but this view may neglect their potential positive impacts on water availability. The effect of trees on soil hydraulic properties linked to groundwater recharge is poorly understood. In this study, we performed 18 rainfall simulations and tracer experiments in an agroforestry parkland in Burkina Faso to investigate the effect of trees and associated termite mounds on soil infiltrability and preferential flow. The sampling points were distributed in transects each consisting of three positions: (i) under a single tree, (ii) in the middle of an open area, and (iii) under a tree associated with a termite mound. The degree of preferential flow was quantified through parameters based on the dye infiltration patterns, which were analyzed using image analysis of photographs. Our results show that the degree of preferential flow was highest under trees associated with termite mounds, intermediate under single trees, and minimal in the open areas. Tree density also had an influence on the degree of preferential flow, with small open areas having more preferential flow than large ones. Soil infiltrability was higher under single trees than in the open areas or under trees associated with a termite mound. The findings from this study demonstrate that trees have a positive impact on soil hydraulic properties influencing groundwater recharge, and thus such effects must be considered when evaluating the impact of trees on water resources in drylands.

  20. Impact of preferential sampling on exposure prediction and health effect inference in the context of air pollution epidemiology

    Science.gov (United States)

    Lee, A.; Szpiro, A.; Kim, S.Y.; Sheppard, L.

    2018-01-01

    Summary Preferential sampling has been defined in the context of geostatistical modeling as the dependence between the sampling locations and the process that describes the spatial structure of the data. It can occur when networks are designed to find high values. For example, in networks based on the U.S. Clean Air Act monitors are sited to determine whether air quality standards are exceeded. We study the impact of the design of monitor networks in the context of air pollution epidemiology studies. The effect of preferential sampling has been illustrated in the literature by highlighting its impact on spatial predictions. In this paper, we use these predictions as input in a second stage analysis, and we assess how they affect health effect inference. Our work is motivated by data from two United States regulatory networks and health data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution. The two networks were designed to monitor air pollution in urban and rural areas respectively, and we found that the health analysis results based on the two networks can lead to different scientific conclusions. We use preferential sampling to gain insight into these differences. We designed a simulation study, and found that the validity and reliability of the health effect estimate can be greatly affected by how we sample the monitor locations. To better understand its effect on second stage inference, we identify two components of preferential sampling that shed light on how preferential sampling alters the properties of the health effect estimate. PMID:29576734

  1. Balancing practicality and hydrologic realism: a parsimonious approach for simulating rapid groundwater recharge via unsaturated-zone preferential flow

    Science.gov (United States)

    Mirus, Benjamin B.; Nimmo, J.R.

    2013-01-01

    The impact of preferential flow on recharge and contaminant transport poses a considerable challenge to water-resources management. Typical hydrologic models require extensive site characterization, but can underestimate fluxes when preferential flow is significant. A recently developed source-responsive model incorporates film-flow theory with conservation of mass to estimate unsaturated-zone preferential fluxes with readily available data. The term source-responsive describes the sensitivity of preferential flow in response to water availability at the source of input. We present the first rigorous tests of a parsimonious formulation for simulating water table fluctuations using two case studies, both in arid regions with thick unsaturated zones of fractured volcanic rock. Diffuse flow theory cannot adequately capture the observed water table responses at both sites; the source-responsive model is a viable alternative. We treat the active area fraction of preferential flow paths as a scaled function of water inputs at the land surface then calibrate the macropore density to fit observed water table rises. Unlike previous applications, we allow the characteristic film-flow velocity to vary, reflecting the lag time between source and deep water table responses. Analysis of model performance and parameter sensitivity for the two case studies underscores the importance of identifying thresholds for initiation of film flow in unsaturated rocks, and suggests that this parsimonious approach is potentially of great practical value.

  2. Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture.

    Science.gov (United States)

    Grunert, Oliver; Reheul, Dirk; Van Labeke, Marie-Christine; Perneel, Maaike; Hernandez-Sanabria, Emma; Vlaeminck, Siegfried E; Boon, Nico

    2016-05-01

    Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated €15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  3. Cultural systems for growing potatoes in space

    Science.gov (United States)

    Tibbitts, T.; Bula, R.; Corey, R.; Morrow, R.

    1988-01-01

    Higher plants are being evaluated for life support to provide needed food, oxygen and water as well as removal of carbon dioxide from the atmosphere. The successful utilization of plants in space will require the development of not only highly productive growing systems but also highly efficient bioregenerative systems. It will be necessary to recycle all inedible plant parts and all human wastes so that the entire complement of elemental compounds can be reused. Potatoes have been proposed as one of the desirable crops because they are 1) extremely productive, yielding more than 100 metric tons per hectare from field plantings, 2) the edible tubers are high in digestible starch (70%) and protein (10%) on a dry weight basis, 3) up to 80% of the total plant production is in tubers and thus edible, 4) the plants are easily propagated either from tubers or from tissue culture plantlets, 5) the tubers can be utilized with a minimum of processing, and 6) potatoes can be prepared in a variety of different forms for the human diet (Tibbitts et al., 1982). However potatoes have a growth pattern that complicates the development of growing the plants in controlled systems. Tubers are borne on underground stems that are botanically termed 'rhizomes', but in common usage termed 'stolons'. The stolons must be maintained in a dark, moist area with sufficient provision for enlargement of tubers. Stems rapidly terminate in flowers forcing extensive branching and spreading of plants so that individual plants will cover 0.2 m2 or more area. Thus the growing system must be developed to provide an area that is darkened for tuber and root growth and of sufficient size for plant spread. A system developed for growing potatoes, or any plants, in space will have certain requirements that must be met to make them a useful part of a life support system. The system must 1) be constructed of materials, and involve media, that can be reused for many successive cycles of plant growth, 2

  4. Nurturing a growing field: Computers & Geosciences

    Science.gov (United States)

    Mariethoz, Gregoire; Pebesma, Edzer

    2017-10-01

    Computational issues are becoming increasingly critical for virtually all fields of geoscience. This includes the development of improved algorithms and models, strategies for implementing high-performance computing, or the management and visualization of the large datasets provided by an ever-growing number of environmental sensors. Such issues are central to scientific fields as diverse as geological modeling, Earth observation, geophysics or climatology, to name just a few. Related computational advances, across a range of geoscience disciplines, are the core focus of Computers & Geosciences, which is thus a truly multidisciplinary journal.

  5. Play Games to Grow up Bilingual

    DEFF Research Database (Denmark)

    Valente, Andrea; Marchetti, Emanuela

    2007-01-01

    A new kind of computer game is proposed, to support the linguistic development of primary school children, growing in multilingual environments: with it players will be able to simultaneously learn multiple languages. The novel idea is to treat words in different languages as physical items......, that the player can collect and exchange for other words or for concrete objects. A prototype is currently under development, and it will be tested in cooperation with local schools. By design this linguistic game will also be extensible, so parents and teachers can tailor it with respect to languages...... and learning contexts....

  6. Play Games to Grow up Bilingual

    DEFF Research Database (Denmark)

    Valente, Andrea; Marchetti, Emanuela

    2008-01-01

    A new kind of computer game is proposed, to support the linguistic development of primary school children, growing in multilingual environments: with it players will be able to simultaneously learn multiple languages. The novel idea is to treat words in different languages as physical items......, that the player can collect and exchange for other words or for concrete objects. A prototype is currently under development, and it will be tested in cooperation with local schools. By design this linguistic game will also be extensible, so parents and teachers can tailor it with respect to languages...... and learning contexts....

  7. Parallelized Seeded Region Growing Using CUDA

    Directory of Open Access Journals (Sweden)

    Seongjin Park

    2014-01-01

    Full Text Available This paper presents a novel method for parallelizing the seeded region growing (SRG algorithm using Compute Unified Device Architecture (CUDA technology, with intention to overcome the theoretical weakness of SRG algorithm of its computation time being directly proportional to the size of a segmented region. The segmentation performance of the proposed CUDA-based SRG is compared with SRG implementations on single-core CPUs, quad-core CPUs, and shader language programming, using synthetic datasets and 20 body CT scans. Based on the experimental results, the CUDA-based SRG outperforms the other three implementations, advocating that it can substantially assist the segmentation during massive CT screening tests.

  8. Light colour preference of growing rabbits

    Directory of Open Access Journals (Sweden)

    Zsolt Szendrő

    2010-01-01

    Full Text Available The objective of the experiment was to evaluate the light colour preference of growing rabbits placed in a free-choice cage. The experiment was carried out on 128 Pannon White growing rabbits weaned at the age of 5 weeks and placed into blocks (2m2 of four cages. The rabbits could move freely among the four cages (0.5m2 each through swing doors. The cages differed only in the colour of the light applied (white, yellow, green or blue. The lighting schedule was 16L: 8D. From 6 until 10 weeks of age, infrared video recording was performed once a week (24 hours. The number of rabbits in each cage was counted every 15 minutes. Feed consumption was measured weekly. Between 6 and 10 weeks of age the rabbits significantly preferred white light (28.0%. The preference order was the following: yellow (26.3%, blue (23.4% and green (22.3% (P<0.001. No significant differences were recorded in the feed consumption among the cages. In conclusion, the cage preference of the rabbits was slightly affected by the light colour.

  9. Mechanotransduction mechanisms in growing spherically structured tissues

    Science.gov (United States)

    Littlejohns, Euan; Dunlop, Carina M.

    2018-04-01

    There is increasing experimental interest in mechanotransduction in multi-cellular tissues as opposed to single cells. This is driven by a growing awareness of the importance of physiologically relevant three-dimensional culture and of cell–cell and cell–gel interactions in directing growth and development. The paradigm biophysical technique for investigating tissue level mechanobiology in this context is to grow model tissues in artificial gels with well-defined mechanical properties. These studies often indicate that the stiffness of the encapsulating gel can significantly alter cellular behaviours. We demonstrate here potential mechanisms linking tissue growth with stiffness-mediated mechanotransduction. We show how tissue growth in gel systems generates points at which there is a significant qualitative change in the cellular stress and strain experienced. We show analytically how these potential switching points depend on the mechanical properties of the constraining gel and predict when they will occur. Significantly, we identify distinct mechanisms that act separately in each of the stress and strain fields at different times. These observations suggest growth as a potential physical mechanism coupling gel stiffness with cellular mechanotransduction in three-dimensional tissues. We additionally show that non-proliferating areas, in the case that the constraining gel is soft compared with the tissue, will expand and contract passively as a result of growth. Central compartment size is thus seen to not be a reliable indicator on its own for growth initiation or active behaviour.

  10. Optimally growing boundary layer disturbances in a convergent nozzle preceded by a circular pipe

    Science.gov (United States)

    Uzun, Ali; Davis, Timothy B.; Alvi, Farrukh S.; Hussaini, M. Yousuff

    2017-06-01

    We report the findings from a theoretical analysis of optimally growing disturbances in an initially turbulent boundary layer. The motivation behind this study originates from the desire to generate organized structures in an initially turbulent boundary layer via excitation by disturbances that are tailored to be preferentially amplified. Such optimally growing disturbances are of interest for implementation in an active flow control strategy that is investigated for effective jet noise control. Details of the optimal perturbation theory implemented in this study are discussed. The relevant stability equations are derived using both the standard decomposition and the triple decomposition. The chosen test case geometry contains a convergent nozzle, which generates a Mach 0.9 round jet, preceded by a circular pipe. Optimally growing disturbances are introduced at various stations within the circular pipe section to facilitate disturbance energy amplification upstream of the favorable pressure gradient zone within the convergent nozzle, which has a stabilizing effect on disturbance growth. Effects of temporal frequency, disturbance input and output plane locations as well as separation distance between output and input planes are investigated. The results indicate that optimally growing disturbances appear in the form of longitudinal counter-rotating vortex pairs, whose size can be on the order of several times the input plane mean boundary layer thickness. The azimuthal wavenumber, which represents the number of counter-rotating vortex pairs, is found to generally decrease with increasing separation distance. Compared to the standard decomposition, the triple decomposition analysis generally predicts relatively lower azimuthal wavenumbers and significantly reduced energy amplification ratios for the optimal disturbances.

  11. Preferential adsorption of polycarboxylate superplasticizers on cement and silica fume in ultra-high performance concrete (UHPC)

    International Nuclear Information System (INIS)

    Schröfl, Ch.; Gruber, M.; Plank, J.

    2012-01-01

    UHPC is fluidized particularly well when a blend of MPEG- and APEG-type PCEs is applied. Here, the mechanism for this behavior was investigated. Testing individual cement and micro silica pastes revealed that the MPEG-PCE disperses cement better than silica whereas the APEG-PCE fluidizes silica particularly well. This behavior is explained by preferential adsorption of APEG-PCE on silica while MPEG-PCEs exhibit a more balanced affinity to both cement and silica. Adsorption data obtained from individual cement and micro silica pastes were compared with those found for the fully formulated UHPC containing a cement/silica blend. In the UHPC formulation, both PCEs still exhibit preferential and selective adsorption similar as was observed for individual cement and silica pastes. Preferential adsorption of PCEs is explained by their different stereochemistry whereby the carboxylate groups have to match with the steric position of calcium ions/atoms situated at the surfaces of cement hydrates or silica.

  12. Refinement by Rietveld method of a rolled sheet Al-Mg-Si 6063 alloy with preferential orientation

    International Nuclear Information System (INIS)

    Carrio, J.A.G.; Hattori, C.S.; Miranda, L.F.; Domingues Junior, N.I.; Lima, N.B.; Couto, A.A.; Aguiar, A.A.

    2010-01-01

    The Rietveld refinement of a sample with preferential orientation was accomplished using data of X ray diffraction of a rolled 6063 aluminum alloy. The refinement of the preferential orientation by spherical harmonic was accomplished using a symmetry of sample mmm (rolling) until the order of 8 and was compared with experimental pole figures. The four pole figures presented indicate a sharp texture of the planes (111), (200), (220) and (311). The calculated pole figures obtained from the refinement of the X ray diffraction spectrum can incur in mistakes of preferential orientation. This happens because the measure is restricted to the planes parallel to the surface without inference to the symmetry of the sample. (author)

  13. Preferential Flow Paths Allow Deposition of Mobile Organic Carbon Deep into Soil B Horizons

    Science.gov (United States)

    Marin-Spiotta, E.; Chadwick, O.; Kramer, M. G.

    2009-12-01

    Most of our understanding of soil carbon (C) dynamics derives from the top 10 to 20 cm, although globally the majority of the bulk soil C pool is found below those depths. Mineral associated C in deep soil is more stable than that held in surface horizons, and its long-term persistence may contribute to sequestration of anthropogenic C. Carbon can enter deep soil horizons in multiple ways: through biologically-mediated or abiotic physical mixing, illuviation, root inputs, or through a physical disturbance that would cause the burial of an originally shallow organic horizon. In this study, we investigated the role of dissolved organic matter (DOM) in the transport and stabilization of soil C in tropical rainforest volcanic soils, where high rainfall, a highly productive forest, and dominance of highly reactive, non-crystalline minerals contribute to large soil C stocks at depth with long mean residence times. DOM plays an important role in many biological and chemical processes in soils, including nutrient transfer within and across ecosystems. Carbon storage in these soils is linked to movement of both DOC and particulate organic C along infiltration pathways. Climate and soil mineralogical properties create the right conditions for C to be pumped from the organic horizons where microbial activity is highest, to deep mineral horizons, where the potential for stabilization is greatest. High rainfall preserves hydrated short-range order minerals that are subject to strong shrinkage during occasional drought periods. The resulting cracks in subsurface B horizons become pathways for DOM complexed with Fe and Al moving in soil solution during subsequent wet periods. Preferential flow of these organically rich solutes and/or colloids moves C to depth where C, Fe and Al are preferentially deposited on near-vertical crack surfaces and along near-horizonal flow surfaces at horizon boundaries. Long-term deposition forms discontinuous Fe- and OM-cemented lamella that serve to

  14. THE FASTEST GROWING LEAST DEVELOPED COUNTRIES

    Directory of Open Access Journals (Sweden)

    Wioletta NOWAK

    2017-12-01

    Full Text Available The paper presents trends in economic growth and development in twelve least developed countries from 2006 to 2015. The study is based on the data retrieved from the World Bank Database. During the analysed 10 years, seven Asian (Myanmar, Lao PDR, Bhutan, Cambodia, Timor-Leste, Bangladesh, and Afghanistan and five African (Ethiopia, Rwanda, Angola, Sudan, and Mozambique LDCs had average annual GDP per capita growth rates higher than 4.0%. GDP has been largely generated through the services and industry sectors. A few LDCs sustained strong growth mainly because of foreign assistance and in other countries remittances were a significant source of development finance. Resource rich countries recorded high inflows of foreign direct investment. In a few fast growing LDCs the state has been heavily engaged in economy. The analysed LDCs substantially improved their development indicators.

  15. Growing hierarchical probabilistic self-organizing graphs.

    Science.gov (United States)

    López-Rubio, Ezequiel; Palomo, Esteban José

    2011-07-01

    Since the introduction of the growing hierarchical self-organizing map, much work has been done on self-organizing neural models with a dynamic structure. These models allow adjusting the layers of the model to the features of the input dataset. Here we propose a new self-organizing model which is based on a probabilistic mixture of multivariate Gaussian components. The learning rule is derived from the stochastic approximation framework, and a probabilistic criterion is used to control the growth of the model. Moreover, the model is able to adapt to the topology of each layer, so that a hierarchy of dynamic graphs is built. This overcomes the limitations of the self-organizing maps with a fixed topology, and gives rise to a faithful visualization method for high-dimensional data.

  16. Personal stories of growing up sexually.

    Science.gov (United States)

    Beausang, C C

    2000-01-01

    Prevention of problems related to sexuality during adolescence continues to be a major public health challenge. Describing childhood perceptions of sexuality is an important step in understanding sexual issues during adolescence. However, there is a paucity of information about sexuality in early life. Therefore, the purpose of this study was to describe recurrent themes in personal stories of growing up sexually. A thematic analysis with a narrative perspective was applied using the method described by Miles and Huberman (1994). Four interrelated themes pervaded the stories: parents as teachers, sex is secret, learning by experience, and first intercourse as a turning point. These findings have major implications for sexual health education and counseling in addition to further research.

  17. Influence of macroporosity on preferential solute and colloid transport in unsaturated field soils.

    Science.gov (United States)

    Cey, Edwin E; Rudolph, David L; Passmore, Joanna

    2009-06-26

    Transport of solutes and colloids in soils, particularly those subject to preferential flow along macropores, is important for assessing the vulnerability of shallow groundwater to contamination. The objective of this study was to investigate flow and transport phenomena for dissolved and colloid tracers during large infiltration events in partially saturated, macroporous soils. Controlled tracer infiltration tests were completed at two field sites in southern Ontario. A tension infiltrometer (TI) was used to infiltrate water with dissolved Brilliant Blue FCF dye simultaneously with 3.7 microm and 0.53 microm diameter fluorescent microspheres. Infiltration was conducted under maximum infiltration pressure heads ranging from -5.2 to -0.4 cm. All infiltration test sites were excavated to examine and photograph dye-stained flow patterns, map soil features, and collect samples for microsphere enumeration. Results indicated that preferential transport of dye and microspheres via macropores occurred when maximum pressure heads were greater than -3.0 cm, and the corresponding infiltration rates exceeded 2.0 cm h(-1). Dye and microspheres were detected at depths greater than 70 cm under the highest infiltration rates from both sites. Microsphere concentrations in the top 5-10 cm of soil decreased by more than two orders of magnitude relative to input concentrations, yet remained relatively constant with depth thereafter. There was some evidence for increased retention of the 3.7 microm microspheres relative to the 0.53 microm microspheres, particularly at lower infiltration pressures where straining and attachment mechanisms are most prevalent. Microspheres were observed within dye stained soil matrix surrounding individual macropores, illustrating the significance of capillary pressures in controlling the vertical migration of both tracers in the vicinity of the macropores. Overall, microsphere distributions closely followed the dye patterns, with microsphere

  18. The gsdf gene locus harbors evolutionary conserved and clustered genes preferentially expressed in fish previtellogenic oocytes.

    Science.gov (United States)

    Gautier, Aude; Le Gac, Florence; Lareyre, Jean-Jacques

    2011-02-01

    The gonadal soma-derived factor (GSDF) belongs to the transforming growth factor-β superfamily and is conserved in teleostean fish species. Gsdf is specifically expressed in the gonads, and gene expression is restricted to the granulosa and Sertoli cells in trout and medaka. The gsdf gene expression is correlated to early testis differentiation in medaka and was shown to stimulate primordial germ cell and spermatogonia proliferation in trout. In the present study, we show that the gsdf gene localizes to a syntenic chromosomal fragment conserved among vertebrates although no gsdf-related gene is detected on the corresponding genomic region in tetrapods. We demonstrate using quantitative RT-PCR that most of the genes localized in the synteny are specifically expressed in medaka gonads. Gsdf is the only gene of the synteny with a much higher expression in the testis compared to the ovary. In contrast, gene expression pattern analysis of the gsdf surrounding genes (nup54, aff1, klhl8, sdad1, and ptpn13) indicates that these genes are preferentially expressed in the female gonads. The tissue distribution of these genes is highly similar in medaka and zebrafish, two teleostean species that have diverged more than 110 million years ago. The cellular localization of these genes was determined in medaka gonads using the whole-mount in situ hybridization technique. We confirm that gsdf gene expression is restricted to Sertoli and granulosa cells in contact with the premeiotic and meiotic cells. The nup54 gene is expressed in spermatocytes and previtellogenic oocytes. Transcripts corresponding to the ovary-specific genes (aff1, klhl8, and sdad1) are detected only in previtellogenic oocytes. No expression was detected in the gonocytes in 10 dpf embryos. In conclusion, we show that the gsdf gene localizes to a syntenic chromosomal fragment harboring evolutionary conserved genes in vertebrates. These genes are preferentially expressed in previtelloogenic oocytes, and thus, they

  19. A novel physical eco-hydrological model concept for preferential flow based on experimental applications.

    Science.gov (United States)

    Jackisch, Conrad; van Schaik, Loes; Graeff, Thomas; Zehe, Erwin

    2014-05-01

    Preferential flow through macropores often determines hydrological characteristics - especially regarding runoff generation and fast transport of solutes. Macropore settings may yet be very different in nature and dynamics, depending on their origin. While biogenic structures follow activity cycles (e.g. earth worms) and population conditions (e.g. roots), pedogenic and geogenic structures may depend on water stress (e.g. cracks) or large events (e.g. flushed voids between skeleton and soil pipes) or simply persist (e.g. bedrock interface). On the one hand, such dynamic site characteristics can be observed in seasonal changes in its reaction to precipitation. On the other hand, sprinkling experiments accompanied by tracers or time-lapse 3D Ground-Penetrating-Radar are suitable tools to determine infiltration patterns and macropore configuration. However, model representation of the macropore-matrix system is still problematic, because models either rely on effective parameters (assuming well-mixed state) or on explicit advection strongly simplifying or neglecting interaction with the diffusive flow domain. Motivated by the dynamic nature of macropores, we present a novel model approach for interacting diffusive and advective water, solutes and energy transport in structured soils. It solely relies on scale- and process-aware observables. A representative set of macropores (data from sprinkling experiments) determines the process model scale through 1D advective domains. These are connected to a 2D matrix domain which is defined by pedo-physical retention properties. Water is represented as particles. Diffusive flow is governed by a 2D random walk of these particles while advection may take place in the macropore domain. Macropore-matrix interaction is computed as dissipation of the advective momentum of a particle by its experienced drag from the matrix domain. Through a representation of matrix and macropores as connected diffusive and advective domains for water

  20. Ion Frequency Landscape in Growing Plants.

    Directory of Open Access Journals (Sweden)

    Mariusz Pietruszka

    Full Text Available It has been interesting that nearly all of the ion activities that have been analysed thus far have exhibited oscillations that are tightly coupled to growth. Here, we present discrete Fourier transform (DFT spectra with a finite sampling of tip-growing cells and organs that were obtained from voltage measurements of the elongating coleoptiles of maize in situ. The electromotive force (EMF oscillations (~ 0.1 μV were measured in a simple but highly sensitive resistor-inductor circuit (RL circuit, in which the solenoid was initially placed at the tip of the specimen and then was moved thus changing its position in relation to growth (EMF can be measured first at the tip, then at the sub-apical part and finally at the shank. The influx- and efflux-induced oscillations of Ca2+, along with H+, K+ and Cl- were densely sampled (preserving the Nyquist theorem in order to 'grasp the structure' of the pulse, the logarithmic amplitude of pulse spectrum was calculated, and the detected frequencies, which displayed a periodic sequence of pulses, were compared with the literature data. A band of life vital individual pulses was obtained in a single run of the experiment, which not only allowed the fundamental frequencies (and intensities of the processes to be determined but also permitted the phase relations of the various transport processes in the plasma membrane and tonoplast to be established. A discrete (quantised frequency spectrum was achieved for a growing plant for the first time, while all of the metabolic and enzymatic functions of the life cell cycle were preserved using this totally non-invasive treatment.

  1. Liberated PKA Catalytic Subunits Associate with the Membrane via Myristoylation to Preferentially Phosphorylate Membrane Substrates.

    Science.gov (United States)

    Tillo, Shane E; Xiong, Wei-Hong; Takahashi, Maho; Miao, Sheng; Andrade, Adriana L; Fortin, Dale A; Yang, Guang; Qin, Maozhen; Smoody, Barbara F; Stork, Philip J S; Zhong, Haining

    2017-04-18

    Protein kinase A (PKA) has diverse functions in neurons. At rest, the subcellular localization of PKA is controlled by A-kinase anchoring proteins (AKAPs). However, the dynamics of PKA upon activation remain poorly understood. Here, we report that elevation of cyclic AMP (cAMP) in neuronal dendrites causes a significant percentage of the PKA catalytic subunit (PKA-C) molecules to be released from the regulatory subunit (PKA-R). Liberated PKA-C becomes associated with the membrane via N-terminal myristoylation. This membrane association does not require the interaction between PKA-R and AKAPs. It slows the mobility of PKA-C and enriches kinase activity on the membrane. Membrane-residing PKA substrates are preferentially phosphorylated compared to cytosolic substrates. Finally, the myristoylation of PKA-C is critical for normal synaptic function and plasticity. We propose that activation-dependent association of PKA-C renders the membrane a unique PKA-signaling compartment. Constrained mobility of PKA-C may synergize with AKAP anchoring to determine specific PKA function in neurons. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  2. HARP preferentially co-purifies with RPA bound to DNA-PK and blocks RPA phosphorylation.

    Science.gov (United States)

    Quan, Jinhua; Yusufzai, Timur

    2014-05-01

    The HepA-related protein (HARP/SMARCAL1) is an ATP-dependent annealing helicase that is capable of rewinding DNA structures that are stably unwound due to binding of the single-stranded DNA (ssDNA)-binding protein Replication Protein A (RPA). HARP has been implicated in maintaining genome integrity through its role in DNA replication and repair, two processes that generate RPA-coated ssDNA. In addition, mutations in HARP cause a rare disease known as Schimke immuno-osseous dysplasia. In this study, we purified HARP containing complexes with the goal of identifying the predominant factors that stably associate with HARP. We found that HARP preferentially interacts with RPA molecules that are bound to the DNA-dependent protein kinase (DNA-PK). We also found that RPA is phosphorylated by DNA-PK in vitro, while the RPA-HARP complexes are not. Our results suggest that, in addition to its annealing helicase activity, which eliminates the natural binding substrate for RPA, HARP blocks the phosphorylation of RPA by DNA-PK.

  3. Preferential binding of yeast Rad4-Rad23 complex to damaged DNA

    International Nuclear Information System (INIS)

    Jansen, L.E.T.; Verhage, R.A.; Brouwer, J.

    1998-01-01

    The yeast Rad4 and Rad23 proteins form a complex that is involved in nucleotide excision repair (NER). Their function in this process is not known yet, but genetic data suggest that they act in an early step in NER. We have purified an epitope-tagged Rad4.Rad23 (tRad4. Rad23) complex from yeast cells, using a clone overproducing Rad4 with a hemagglutinin-tag at its C terminus. tRad4.Rad23 complex purified by both conventional and immuno-affinity chromatography complements the in vitro repair defect of rad4 and rad23 mutant extracts, demonstrating that these proteins are functional in NER. Using electrophoretic mobility shift assays, we show preferential binding of the tRad4.Rad23 complex to damaged DNA in vitro. UV-irradiated, as well as N-acetoxy-2-(acetylamino)fluorene-treated DNA, is efficiently bound by the protein complex. These data suggest that Rad4.Rad23 interacts with DNA damage during NER and may play a role in recognition of the damage

  4. Counter-regulating on the Internet: Threat elicits preferential processing of positive information.

    Science.gov (United States)

    Greving, Hannah; Sassenberg, Kai; Fetterman, Adam

    2015-09-01

    The Internet is a central source of information. It is increasingly used for information search in self-relevant domains (e.g., health). Self-relevant topics are also associated with specific emotions and motivational states. For example, individuals may fear serious illness and feel threatened. Thus far, the impact of threat has received little attention in Internet-based research. The current studies investigated how threat influences Internet search. Threat is known to elicit the preferential processing of positive information. The self-directed nature of Internet search should particularly provide opportunities for such processing behavior. We predicted that during Internet search, more positive information would be processed (i.e., allocated more attention to) and more positive knowledge would be acquired under threat than in a control condition. Three experiments supported this prediction: Under threat, attention is directed more to positive web pages (Study 1) and positive links (Study 2), and more positive information is acquired (Studies 1 and 3) than in a control condition. Notably, the effect on knowledge acquisition was mediated by the effect on attention allocation during an actual Internet search (Study 1). Thus, Internet search under threat leads to selective processing of positive information and dampens threatened individuals' negative affect. (c) 2015 APA, all rights reserved).

  5. Motile hepatocellular carcinoma cells preferentially secret sugar metabolism regulatory proteins via exosomes.

    Science.gov (United States)

    Zhang, Jing; Lu, Shaohua; Zhou, Ye; Meng, Kun; Chen, Zhipeng; Cui, Yizhi; Shi, Yunfeng; Wang, Tong; He, Qing-Yu

    2017-07-01

    Exosomes are deliverers of critically functional proteins, capable of transforming target cells in numerous cancers, including hepatocellular carcinoma (HCC). We hypothesize that the motility of HCC cells can be featured by comparative proteome of exosomes. Hence, we performed the super-SILAC-based MS analysis on the exosomes secreted by three human HCC cell lines, including the non-motile Hep3B cell, and the motile 97H and LM3 cells. More than 1400 exosomal proteins were confidently quantified in each MS analysis with highly biological reproducibility. We justified that 469 and 443 exosomal proteins represented differentially expressed proteins (DEPs) in the 97H/Hep3B and LM3/Hep3B comparisons, respectively. These DEPs focused on sugar metabolism-centric canonical pathways per ingenuity pathway analysis, which was consistent with the gene ontology analysis on biological process enrichment. These pathways included glycolysis I, gluconeogenesis I and pentose phosphate pathways; and the DEPs enriched in these pathways could form a tightly connected network. By analyzing the relative abundance of proteins and translating mRNAs, we found significantly positive correlation between exosomes and cells. The involved exosomal proteins were again focusing on sugar metabolism. In conclusion, motile HCC cells tend to preferentially export more sugar metabolism-associated proteins via exosomes that differentiate them from non-motile HCC cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Aminopropyltransferases involved in polyamine biosynthesis localize preferentially in the nucleus of plant cells.

    Directory of Open Access Journals (Sweden)

    Borja Belda-Palazón

    Full Text Available Plant aminopropyltransferases consist of a group of enzymes that transfer aminopropyl groups derived from decarboxylated S-adenosyl-methionine (dcAdoMet or dcSAM to propylamine acceptors to produce polyamines, ubiquitous metabolites with positive charge at physiological pH. Spermidine synthase (SPDS uses putrescine as amino acceptor to form spermidine, whereas spermine synthase (SPMS and thermospermine synthase (TSPMS use spermidine as acceptor to synthesize the isomers spermine and thermospermine respectively. In previous work it was shown that both SPDS1 and SPDS2 can physically interact with SPMS although no data concerning the subcellular localization was reported. Here we study the subcellular localization of these enzymes and their protein dimer complexes with gateway-based Bimolecular Fluorescence Complementation (BiFC binary vectors. In addition, we have characterized the molecular weight of the enzyme complexes by gel filtration chromatography with in vitro assembled recombinant enzymes and with endogenous plant protein extracts. Our data suggest that aminopropyltransferases display a dual subcellular localization both in the cytosol and nuclear enriched fractions, and they assemble preferably as dimers. The BiFC transient expression data suggest that aminopropyltransferase heterodimer complexes take place preferentially inside the nucleus.

  7. Rapid and preferential activation of the c-jun gene during the mammalian UV response

    International Nuclear Information System (INIS)

    Devary, Y.; Gottlieb, R.A.; Lau, L.F.; Karin, M.

    1991-01-01

    Exposure of mammalian cells to DNA-damaging agents leads to activation of a genetic response known as the UV response. Because several previously identified UV-inducible genes contain AP-1 binding sites within their promoters, we investigated the induction of AP-1 activity by DNA-damaging agents. We found that expression of both c-jun and c-fos, which encode proteins that participate in formation of the AP-1 complex, is rapidly induced by two different DNA-damaging agents: UV and H2O2. Interestingly, the c-jun gene is far more responsive to UV than any other immediate-early gene that was examined, including c-fos. Other jun and fos genes were only marginally affected by UV or H2O2. Furthermore, UV is a much more efficient inducer of c-jun than phorbol esters, the standard inducers of c-jun expression. This preferential response of the c-jun gene is mediated by its 5' control region and requires the TPA response element, suggesting that this element also serves as an early target for the signal transduction pathway elicited by DNA damage. Both UV and H2O2 lead to a long-lasting increase in AP-1 binding activity, suggesting that AP-1 may mediate the induction of other damage-inducible genes such as human collagenase

  8. Non-preferential fuelling of the Na(+)/K(+)-ATPase pump.

    Science.gov (United States)

    Fernández-Moncada, Ignacio; Barros, L Felipe

    2014-06-15

    There is abundant evidence that glycolysis and the Na(+)/K(+)-ATPase pump are functionally coupled, and it is thought that the nature of the coupling is energetic, with glycolysis providing the ATP that fuels the pump. This notion has been instrumental to current models of brain energy metabolism. However, structural and biophysical considerations suggest that the pump should also have access to mitochondrial ATP, which is much more abundant. In the present study, we have investigated the source of ATP that fuels the Na(+) pump in astrocytes, taking advantage of the high temporal resolution of recently available FRET nanosensors for glucose, lactate and ATP. The activity of the Na(+) pump was assessed in parallel with the Na(+)-sensitive dye SBFI AM (Na(+)-binding benzofuran isophthalate acetoxymethyl ester). OXPHOS (oxidative phosphorylation) inhibition resulted in bulk ATP depletion and a 5-fold stimulation of glycolytic flux, in spite of which Na(+) pumping was inhibited by 90%. Mathematical modelling of ATP dynamics showed that the observed pump failure is inconsistent with preferential fuelling of the Na(+) pump by glycolytic ATP. We conclude that the nature of the functional coupling between the Na(+) pump and the glycolytic machinery is not energetic and that the pump is mainly fuelled by mitochondrial ATP.

  9. Thermodynamics, maximum power, and the dynamics of preferential river flow structures at the continental scale

    Directory of Open Access Journals (Sweden)

    A. Kleidon

    2013-01-01

    Full Text Available The organization of drainage basins shows some reproducible phenomena, as exemplified by self-similar fractal river network structures and typical scaling laws, and these have been related to energetic optimization principles, such as minimization of stream power, minimum energy expenditure or maximum "access". Here we describe the organization and dynamics of drainage systems using thermodynamics, focusing on the generation, dissipation and transfer of free energy associated with river flow and sediment transport. We argue that the organization of drainage basins reflects the fundamental tendency of natural systems to deplete driving gradients as fast as possible through the maximization of free energy generation, thereby accelerating the dynamics of the system. This effectively results in the maximization of sediment export to deplete topographic gradients as fast as possible and potentially involves large-scale feedbacks to continental uplift. We illustrate this thermodynamic description with a set of three highly simplified models related to water and sediment flow and describe the mechanisms and feedbacks involved in the evolution and dynamics of the associated structures. We close by discussing how this thermodynamic perspective is consistent with previous approaches and the implications that such a thermodynamic description has for the understanding and prediction of sub-grid scale organization of drainage systems and preferential flow structures in general.

  10. Characterization of Putative cis-Regulatory Elements in Genes Preferentially Expressed in Arabidopsis Male Meiocytes

    Directory of Open Access Journals (Sweden)

    Junhua Li

    2014-01-01

    Full Text Available Meiosis is essential for plant reproduction because it is the process during which homologous chromosome pairing, synapsis, and meiotic recombination occur. The meiotic transcriptome is difficult to investigate because of the size of meiocytes and the confines of anther lobes. The recent development of isolation techniques has enabled the characterization of transcriptional profiles in male meiocytes of Arabidopsis. Gene expression in male meiocytes shows unique features. The direct interaction of transcription factors (TFs with DNA regulatory sequences forms the basis for the specificity of transcriptional regulation. Here, we identified putative cis-regulatory elements (CREs associated with male meiocyte-expressed genes using in silico tools. The upstream regions (1 kb of the top 50 genes preferentially expressed in Arabidopsis meiocytes possessed conserved motifs. These motifs are putative binding sites of TFs, some of which share common functions, such as roles in cell division. In combination with cell-type-specific analysis, our findings could be a substantial aid for the identification and experimental verification of the protein-DNA interactions for the specific TFs that drive gene expression in meiocytes.

  11. Arctigenin preferentially induces tumor cell death under glucose deprivation by inhibiting cellular energy metabolism.

    Science.gov (United States)

    Gu, Yuan; Qi, Chunting; Sun, Xiaoxiao; Ma, Xiuquan; Zhang, Haohao; Hu, Lihong; Yuan, Junying; Yu, Qiang

    2012-08-15

    Selectively eradicating cancer cells with minimum adverse effects on normal cells is a major challenge in the development of anticancer therapy. We hypothesize that nutrient-limiting conditions frequently encountered by cancer cells in poorly vascularized solid tumors might provide an opportunity for developing selective therapy. In this study, we investigated the function and molecular mechanisms of a natural compound, arctigenin, in regulating tumor cell growth. We demonstrated that arctigenin selectively promoted glucose-starved A549 tumor cells to undergo necrosis by inhibiting mitochondrial respiration. In doing so, arctigenin elevated cellular level of reactive oxygen species (ROS) and blocked cellular energy metabolism in the glucose-starved tumor cells. We also demonstrated that cellular ROS generation was caused by intracellular ATP depletion and played an essential role in the arctigenin-induced tumor cell death under the glucose-limiting condition. Furthermore, we combined arctigenin with the glucose analogue 2-deoxyglucose (2DG) and examined their effects on tumor cell growth. Interestingly, this combination displayed preferential cell-death inducing activity against tumor cells compared to normal cells. Hence, we propose that the combination of arctigenin and 2DG may represent a promising new cancer therapy with minimal normal tissue toxicity. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  12. Mean First Passage Time of Preferential Random Walks on Complex Networks with Applications

    Directory of Open Access Journals (Sweden)

    Zhongtuan Zheng

    2017-01-01

    Full Text Available This paper investigates, both theoretically and numerically, preferential random walks (PRW on weighted complex networks. By using two different analytical methods, two exact expressions are derived for the mean first passage time (MFPT between two nodes. On one hand, the MFPT is got explicitly in terms of the eigenvalues and eigenvectors of a matrix associated with the transition matrix of PRW. On the other hand, the center-product-degree (CPD is introduced as one measure of node strength and it plays a main role in determining the scaling of the MFPT for the PRW. Comparative studies are also performed on PRW and simple random walks (SRW. Numerical simulations of random walks on paradigmatic network models confirm analytical predictions and deepen discussions in different aspects. The work may provide a comprehensive approach for exploring random walks on complex networks, especially biased random walks, which may also help to better understand and tackle some practical problems such as search and routing on networks.

  13. Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise [Department of Biological Sciences, Boise State University, Boise, ID 83725 (United States); Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew [Department of Physics, Boise State University, Boise, ID 83725 (United States)], E-mail: denisewingett@boisestate.edu

    2008-07-23

    Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells ({approx}28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity.

  14. Preferential control of basal dendritic protrusions by EphB2.

    Directory of Open Access Journals (Sweden)

    Matthew S Kayser

    2011-02-01

    Full Text Available The flow of information between neurons in many neural circuits is controlled by a highly specialized site of cell-cell contact known as a synapse. A number of molecules have been identified that are involved in central nervous system synapse development, but knowledge is limited regarding whether these cues direct organization of specific synapse types or on particular regions of individual neurons. Glutamate is the primary excitatory neurotransmitter in the brain, and the majority of glutamatergic synapses occur on mushroom-shaped protrusions called dendritic spines. Changes in the morphology of these structures are associated with long-lasting modulation of synaptic strength thought to underlie learning and memory, and can be abnormal in neuropsychiatric disease. Here, we use rat cortical slice cultures to examine how a previously-described synaptogenic molecule, the EphB2 receptor tyrosine kinase, regulates dendritic protrusion morphology in specific regions of the dendritic arbor in cortical pyramidal neurons. We find that alterations in EphB2 signaling can bidirectionally control protrusion length, and knockdown of EphB2 expression levels reduces the number of dendritic spines and filopodia. Expression of wild-type or dominant negative EphB2 reveals that EphB2 preferentially regulates dendritic protrusion structure in basal dendrites. Our findings suggest that EphB2 may act to specify synapse formation in a particular subcellular region of cortical pyramidal neurons.

  15. Telecoupled governance of land use change: Sustainable palm oil conservation benefits limited by preferential certification

    Science.gov (United States)

    Heilmayr, R.; Carlson, K. M.; Gibbs, H.; Noojipady, P.; Burns, D.; Morton, D. C.; Walker, N.; Paoli, G.; Kremen, C.

    2016-12-01

    Dozens of trans-national corporations have made public commitments to purchase only zero-deforestation palm oil, a commodity responsible for substantial tropical forest loss. Eco-certification is a basic requirement of most such forest-related procurement policies, and >20% of palm oil was certified in 2015.While the impact of certification on deforestation in oil palm plantations has never been tested, such evaluation is critical to inform improvements of voluntary sustainability initiatives. Here, we use a new, comprehensive data set of Roundtable on Sustainable Palm Oil (RSPO) certified and non-certified oil palm plantation boundaries (191,561 km2) in Indonesia, the leading global producer of palm oil to generate robust spatio-temporal estimates of certification's impact on deforestation and fires from 2000-2014. We find that certification reduced forest cover loss embodied in RSPO certified palm oil through two mechanisms. Certification had a significant protective effect, which lowered plantation deforestation rates by 29%.However, due to preferential certification of plantations developed before 2000, little forest was available for protection; forest area conserved totaled 56±4.9 km2. Our models suggest that increased adoption of RSPO certification may reduce the ability of palm oil companies to selectively certify previously cleared regions, and consequently strengthen the role of certification in protecting the tropical forests at greatest risk from agricultural encroachment. We reflect upon the complex interactions between traditional government policies, and emerging market-based governance structures in this telecoupled system.

  16. Enhancement of GABAergic transmission by zolpidem, an imidazopyridine with preferential affinity for type I benzodiazepine receptors.

    Science.gov (United States)

    Biggio, G; Concas, A; Corda, M G; Serra, M

    1989-02-28

    The effect of zolpidem, an imidazopyridine derivative with high affinity at the type I benzodiazepine recognition site, on the function of the GABAA/ionophore receptor complex was studied in vitro. Zolpidem, mimicking the action of diazepam, increased [3H]GABA binding, enhanced muscimol-stimulated 36Cl- uptake and reduced [35S]TBPS binding in rat cortical membrane preparations. Zolpidem was less effective than diazepam on the above parameters. Zolpidem induced a lower increase of [3H]GABA binding (23 vs. 35%) and muscimol-stimulated 36Cl- uptake (22 vs. 40%) and a smaller decrease of [35S]TBPS binding (47 vs. 77%) than diazepam. The finding that zolpidem enhanced the function of GABAergic synapses with an efficacy qualitatively and quantitatively different from that of diazepam suggests that this compound is a partial agonist at the benzodiazepine recognition site. Thus, our results are consistent with the view that the biochemical and pharmacological profile of a benzodiazepine recognition site ligand reflects its efficacy to enhance GABAergic transmission. Whether the preferential affinity of zolpidem at the type I site is involved in its atypical biochemical and pharmacological profile remains to be clarified.

  17. Preferential responses in amygdala and insula during presentation of facial contempt and disgust.

    Science.gov (United States)

    Sambataro, Fabio; Dimalta, Savino; Di Giorgio, Annabella; Taurisano, Paolo; Blasi, Giuseppe; Scarabino, Tommaso; Giannatempo, Giuseppe; Nardini, Marcello; Bertolino, Alessandro

    2006-10-01

    Some authors consider contempt to be a basic emotion while others consider it a variant of disgust. The neural correlates of contempt have not so far been specifically contrasted with disgust. Using functional magnetic resonance imaging (fMRI), we investigated the neural networks involved in the processing of facial contempt and disgust in 24 healthy subjects. Facial recognition of contempt was lower than that of disgust and of neutral faces. The imaging data indicated significant activity in the amygdala and in globus pallidus and putamen during processing of contemptuous faces. Bilateral insula and caudate nuclei and left as well as right inferior frontal gyrus were engaged during processing of disgusted faces. Moreover, direct comparisons of contempt vs. disgust yielded significantly different activations in the amygdala. On the other hand, disgusted faces elicited greater activation than contemptuous faces in the right insula and caudate. Our findings suggest preferential involvement of different neural substrates in the processing of facial emotional expressions of contempt and disgust.

  18. Depth distribution of preferential flow patterns in a sandy loam soil as affected by tillage

    Directory of Open Access Journals (Sweden)

    C. T. Petersen

    1997-01-01

    Full Text Available Dye-tracer studies using the anionic dye Brilliant Blue FCF were conducted on a structured sandy loam soil (Typic Agrudalf. 25 mm of dye solution was applied to the surface of 11 1.6 x 1.6 m field plots, some of which had been subjected to conventional seed bed preparation (harrowing while others had been rotovated to either 5 or 15 cm depth before sowing. The soil was excavated to about 160 cm depth one or two days after dye application. Flow patterns and structural features appearing on vertical or horizontal cross sections were examined and photographed. The flow patterns were digitized, and depth functions for the number of activated flow pathways and the degree of dye coverage were calculated. Dye was found below 100 cm depth on 26 out of 33 vertical cross sections made in conventionally tilled plots showing that preferential flow was a prevailing phenomenon. The depth-averaged number of stained flow pathways in the 25-100 cm layer was significantly smaller in a plot rotovated to 5 cm depth than in a conventionally tilled plot, both under relatively dry initial soil conditions and when the entire soil profiles were initially at field capacity. There were no examples of dye penetration below 25 cm depth one month after deep rotovation. Distinct horizontal structures in flow patterns appearing at 20-40 cm depth coupled with changes in flow domains indicated soil layering with abrupt changes in soil structure and hydraulic properties.

  19. Heterogeneous Ribosomes Preferentially Translate Distinct Subpools of mRNAs Genome-wide.

    Science.gov (United States)

    Shi, Zhen; Fujii, Kotaro; Kovary, Kyle M; Genuth, Naomi R; Röst, Hannes L; Teruel, Mary N; Barna, Maria

    2017-07-06

    Emerging studies have linked the ribosome to more selective control of gene regulation. However, an outstanding question is whether ribosome heterogeneity at the level of core ribosomal proteins (RPs) exists and enables ribosomes to preferentially translate specific mRNAs genome-wide. Here, we measured the absolute abundance of RPs in translating ribosomes and profiled transcripts that are enriched or depleted from select subsets of ribosomes within embryonic stem cells. We find that heterogeneity in RP composition endows ribosomes with differential selectivity for translating subpools of transcripts, including those controlling metabolism, cell cycle, and development. As an example, mRNAs enriched in binding to RPL10A/uL1-containing ribosomes are shown to require RPL10A/uL1 for their efficient translation. Within several of these transcripts, this level of regulation is mediated, at least in part, by internal ribosome entry sites. Together, these results reveal a critical functional link between ribosome heterogeneity and the post-transcriptional circuitry of gene expression. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Preferential host switching and codivergence shaped radiation of bark beetle symbionts, nematodes of Micoletzkya (Nematoda: Diplogastridae).

    Science.gov (United States)

    Susoy, V; Herrmann, M

    2014-05-01

    Host-symbiont systems are of particular interest to evolutionary biology because they allow testable inferences of diversification processes while also providing both a historical basis and an ecological context for studies of adaptation. Our investigations of bark beetle symbionts, predatory nematodes of the genus Micoletzkya, have revealed remarkable diversity of the group along with a high level of host specificity. Cophylogenetic analyses suggest that evolution of the nematodes was largely influenced by the evolutionary history of beetles. The diversification of the symbionts, however, could not be attributed to parallel divergence alone; our results indicate that adaptive radiation of the nematodes was shaped by preferential host shifts among closely related beetles along with codivergence. Whereas ecological and geographic isolation have played a major role in the diversification of Micoletzkya at shallow phylogenetic depths, adaptations towards related hosts have played a role in shaping cophylogenetic structure at a larger evolutionary scale. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  1. A preferential design approach for energy-efficient and robust implantable neural signal processing hardware.

    Science.gov (United States)

    Narasimhan, Seetharam; Chiel, Hillel J; Bhunia, Swarup

    2009-01-01

    For implantable neural interface applications, it is important to compress data and analyze spike patterns across multiple channels in real time. Such a computational task for online neural data processing requires an innovative circuit-architecture level design approach for low-power, robust and area-efficient hardware implementation. Conventional microprocessor or Digital Signal Processing (DSP) chips would dissipate too much power and are too large in size for an implantable system. In this paper, we propose a novel hardware design approach, referred to as "Preferential Design" that exploits the nature of the neural signal processing algorithm to achieve a low-voltage, robust and area-efficient implementation using nanoscale process technology. The basic idea is to isolate the critical components with respect to system performance and design them more conservatively compared to the noncritical ones. This allows aggressive voltage scaling for low power operation while ensuring robustness and area efficiency. We have applied the proposed approach to a neural signal processing algorithm using the Discrete Wavelet Transform (DWT) and observed significant improvement in power and robustness over conventional design.

  2. B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

    Science.gov (United States)

    Dhar, Manoj K.; Kour, Gurmeet; Kaul, Sanjana

    2017-01-01

    Abstract Plantago lagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes. PMID:28919970

  3. Cytotoxic T cells are preferentially activated in the duodenal epithelium from patients with florid coeliac disease.

    Science.gov (United States)

    Buri, Caroline; Burri, Philipp; Bähler, Peter; Straumann, Alex; Müller-Schenker, Beatrice; Birrer, Stefan; Mueller, Christoph

    2005-06-01

    Villous atrophy and increased numbers of intraepithelial T cells in duodenal biopsies represent a hallmark of coeliac disease. In the present study, an attempt has been made to define whether cytotoxic cell subsets are activated in situ in the affected mucosa of susceptible individuals early after ingestion of a gluten-containing diet. Duodenal biopsies from 11 patients with coeliac disease who repeatedly underwent endoscopic biopsy after ingestion of individually dosed amounts of gluten were used for immunohistochemistry and in situ hybridization. To identify the cell subsets expressing perforin mRNA and protein, in situ hybridization and FACS analyses were performed on cells isolated from fresh biopsies. Compared with normal mucosa, the number of intraepithelial lymphocytes containing perforin mRNA and protein increased significantly in tissue samples showing moderate or florid coeliac disease and closely paralleled the severity of morphological alteration, whereas the frequency of perforin-expressing lamina propria lymphocytes increased only moderately. Cells isolated from florid biopsies that expressed perforin mRNA and protein were preferentially T-cell receptor (TCR) alphabeta T cells. The increase in both the absolute number and the percentage of lymphocytes expressing perforin mRNA indicates in situ activation of lymphocytes within the epithelial compartment in florid coeliac disease upon ingestion of a gluten-containing diet in patients predisposed to coeliac disease. Copyright 2005 Pathological Society of Great Britain and Ireland

  4. Farnesyltransferase inhibitor tipifarnib (R115777) preferentially inhibits in vitro autonomous erythropoiesis of polycythemia vera patient cells.

    Science.gov (United States)

    Larghero, Jérôme; Gervais, Nathalie; Cassinat, Bruno; Rain, Jean-Didier; Schlageter, Marie-Hélène; Padua, Rose Ann; Chomienne, Christine; Rousselot, Philippe

    2005-05-01

    Polycythemia vera (PV) is an acquired myeloproliferative disorder with primary expansion of the red cell mass leading to an increased risk of thrombosis and less frequently to myelofibrosis and secondary acute leukemia. Standard therapies include cytoreduction with either phlebotomy or chemotherapeutic agents and antithrombotic drugs. Because long-term exposure to cytotoxic chemotherapy may increase the risk of acute transformation, new therapeutic options are needed. Tipifarnib is a nonpeptidomimetic inhibitor of farnesyl transferase that was developed as a potential inhibitor of RAS signaling. In the present study we report that tipifarnib used at pharmacologically achievable concentrations strongly inhibits the erythroid burst-forming unit (BFU-E) autonomous growth that characterizes patients with PV. Moreover, at low tipifarnib concentrations (0.15 muM), the inhibitory effect was preferentially observed in PV BFU-E progenitors and not in normal BFU-E progenitors and was not rescued by erythropoietin (EPO). Thus tipifarnib may specifically target PV stem cells and may be of clinical interest in the treatment of patients with PV.

  5. Support Effects in the Gold-Catalyzed Preferential Oxidation of CO

    KAUST Repository

    Ivanova, S.

    2010-04-08

    The study of support effects on the gold-catalyzed preferential oxidation of carbon monoxide in the presence of hydrogen (PROX reaction) is possible only with careful control of the gold particle size, which is facilitated by the application of the direct anionic exchange method. Catalytic evaluation of thermally stable gold nanoparticles, with an average size of around 3 nm on a variety of supports (alumina, titania, zirconia, or ceria), clearly shows that the influence of the support on the CO oxidation rate is of primary importance under CO+O 2 conditions and that this influence becomes secondary in the presence of hydrogen. The impact of the support surface structure on the oxidation rates, catalyst selectivity, and catalyst activation/deactivation is investigated in terms of oxygen vacancies, oxygen mobility, OH groups, and surface area on the oxidation rates, catalyst selectivity and catalyst activation/deactivation. It allows the identification of key morphological and structural features of the support to ensure high activity and selectivity in the gold-catalyzed PROX reaction. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Metformin kills and radiosensitizes cancer cells and preferentially kills cancer stem cells

    Science.gov (United States)

    Song, Chang W.; Lee, Hyemi; Dings, Ruud P. M.; Williams, Brent; Powers, John; Santos, Troy Dos; Choi, Bo-Hwa; Park, Heon Joo

    2012-01-01

    The anti-cancer effects of metformin, the most widely used drug for type 2 diabetes, alone or in combination with ionizing radiation were studied with MCF-7 human breast cancer cells and FSaII mouse fibrosarcoma cells. Clinically achievable concentrations of metformin caused significant clonogenic death in cancer cells. Importantly, metformin was preferentially cytotoxic to cancer stem cells relative to non-cancer stem cells. Metformin increased the radiosensitivity of cancer cells in vitro, and significantly enhanced the radiation-induced growth delay of FSaII tumors (s.c.) in the legs of C3H mice. Both metformin and ionizing radiation activated AMPK leading to inactivation of mTOR and suppression of its downstream effectors such as S6K1 and 4EBP1, a crucial signaling pathway for proliferation and survival of cancer cells, in vitro as well as in the in vivo tumors. Conclusion: Metformin kills and radiosensitizes cancer cells and eradicates radioresistant cancer stem cells by activating AMPK and suppressing mTOR. PMID:22500211

  7. Type II and III Taste Bud Cells Preferentially Expressed Kainate Glutamate Receptors in Rats.

    Science.gov (United States)

    Lee, Sang-Bok; Lee, Cil-Han; Kim, Se-Nyun; Chung, Ki-Myung; Cho, Young-Kyung; Kim, Kyung-Nyun

    2009-12-01

    Glutamate-induced cobalt uptake reveals that non-NMDA glutamate receptors (GluRs) are present in rat taste bud cells. Previous studies involving glutamate induced cobalt staining suggest this uptake mainly occurs via kainate type GluRs. It is not known which of the 4 types of taste bud cells express subunits of kainate GluR. Circumvallate and foliate papillae of Sprague-Dawley rats (45~60 days old) were used to search for the mRNAs of subunits of non-NMDA GluRs using RT-PCR with specific primers for GluR1-7, KA1 and KA2. We also performed RT-PCR for GluR5, KA1, PLCbeta2, and NCAM/SNAP 25 in isolated single cells from taste buds. Taste epithelium, including circumvallate or foliate papilla, express mRNAs of GluR5 and KA1. However, non-taste tongue epithelium expresses no subunits of non-NMDA GluRs. Isolated single cell RT-PCR reveals that the mRNAs of GluR5 and KA1 are preferentially expressed in Type II and Type III cells over Type I cells.

  8. Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen

    Energy Technology Data Exchange (ETDEWEB)

    Khan, S.H.; Sorof, S. (Fox Chase Cancer Center, Philadelphia, PA (United States))

    1990-12-01

    Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ{sub 2}, and {Delta}{sup 12}-PGJ{sub 2}, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth inhibitory prostaglandins by L-FABP and the reversible inhibition of thymidine incorporation into DNA by PGA{sub 2} and {Delta}{sup 12}-PGJ{sub 2} in primary cultures of purified rat hepatocytes. As a model ligand, ({sup 3}H)PGA{sub 1} bound to L-FABP specifically, reversibly, rapidly, and with high affinity. Its dissociation constants were 134 nM (high affinity) and 3.6 {mu}M (low affinity). The high-affinity finding of ({sup 3}H)PGA{sup 1} correlated with their growth inhibitory activities reported previously and here. The in vitro actions of L-FABP are compatible with those of a specific and dissociable carrier of growth inhibitory prostaglandins in rat hepatocytes and suggest that the carcinogen may usurp the cellular machinery of the growth inhibitory prostaglandins.

  9. PREFERENTIAL SECRETION OF INDUCIBLE HSP70 BY VITILIGO MELANOCYTES UNDER STRESS

    Science.gov (United States)

    Mosenson, Jeffrey A.; Flood, Kelsey; Klarquist, Jared; Eby, Jonathan M.; Koshoffer, Amy; Boissy, Raymond E.; Overbeck, Andreas; C.Tung, Rebecca; Poole, I. Caroline Le

    2014-01-01

    SUMMARY Inducible HSP70 (HSP70i) chaperones peptides from stressed cells, protecting them from apoptosis. Upon extracellular release, HSP70i serves an adjuvant function, enhancing immune responses to bound peptides. We questioned whether HSP70i differentially protects control and vitiligo melanocytes from stress and subsequent immune responses. We compared expression of HSP70i in skin samples, evaluated the viability of primary vitiligo and control melanocytes exposed to bleaching phenols, and measured secreted HSP70i. We determined whether HSP70i traffics to melanosomes to contact immunogenic proteins by cell fractionation, western blotting, electron microscopy and confocal microscopy. Viability of vitiligo and control melanocytes was equally affected under stress. However, vitiligo melanocytes secreted increased amounts of HSP70i in response to MBEH, corroborating with aberrant HSP70i expression in patient skin. Intracellular HSP70i colocalized with melanosomes, and more so in response to MBEH in vitiligo melanocytes. Thus whereas either agent is cytotoxic to melanocytes, MBEH preferentially induces immune responses to melanocytes. PMID:24354861

  10. Preferential killing of cancer cells and activated human T cells using ZnO nanoparticles

    International Nuclear Information System (INIS)

    Hanley, Cory; Layne, Janet; Feris, Kevin; Wingett, Denise; Punnoose, Alex; Reddy, K M; Coombs, Isaac; Coombs, Andrew

    2008-01-01

    Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine. Here we examine the response of normal human cells to ZnO nanoparticles under different signaling environments and compare it to the response of cancerous cells. ZnO nanoparticles exhibit a strong preferential ability to kill cancerous T cells (∼28-35 x) compared to normal cells. Interestingly, the activation state of the cell contributes toward nanoparticle toxicity, as resting T cells display a relative resistance while cells stimulated through the T cell receptor and CD28 costimulatory pathway show greater toxicity in direct relation to the level of activation. Mechanisms of toxicity appear to involve the generation of reactive oxygen species, with cancerous T cells producing higher inducible levels than normal T cells. In addition, nanoparticles were found to induce apoptosis and the inhibition of reactive oxygen species was found to be protective against nanoparticle induced cell death. The novel findings of cell selective toxicity, towards potential disease causing cells, indicate a potential utility of ZnO nanoparticles in the treatment of cancer and/or autoimmunity

  11. Angular dependence of preferential sputtering and composition in aluminum--copper thin films

    International Nuclear Information System (INIS)

    Rudeck, P.J.; Harper, J.M.E.; Fryer, P.M.

    1989-01-01

    The copper concentration in aluminum--copper alloys can be altered by ion bombardment during film deposition. We have measured the sputtering yields of aluminum and copper in Al--Cu alloys as a function of the Cu concentration (5--13 at. %) and the angle of ion incidence (0--40 0 from normal). During deposition, the films were partially resputtered by 500-eV Ar + ion bombardment from a Kaufman ion source. We found that the Cu sputtering yield decreases by up to a factor of 10 in the alloy, relative to elemental Cu. The Al sputtering yield remains close to the elemental value. The net effect is a strong preferential sputtering of Al relative to Cu, which enhances the Cu concentration in an ion bombarded film. The Al/Cu sputtering yield ratio for normal incidence ion bombardment ranges from 3 to 5 as a function of Cu concentration. This ratio decreases with increasing angle of incidence to as low as 2 for 40 0 incident ions. However, since a higher fraction of the film is resputtered from a sloping surface, a higher Cu concentration is found on a sloping surface relative to a flat surface. These results show that in multicomponent film deposition under ion bombardment, the film composition will vary as a function of the surface topography. We will also show how the level of argon left trapped in the films varies inversely with respect to the ion flux

  12. Preferential superior surface motion in wear simulations of the Charité total disc replacement.

    Science.gov (United States)

    Goreham-Voss, Curtis M; Vicars, Rachel; Hall, Richard M; Brown, Thomas D

    2012-06-01

    Laboratory wear simulations of the dual-bearing surface Charité total disc replacement (TDR) are complicated by the non-specificity of the device's center of rotation (CoR). Previous studies have suggested that articulation of the Charité preferentially occurs at the superior-bearing surface, although it is not clear how sensitive this phenomenon is to lubrication conditions or CoR location. In this study, a computational wear model is used to study the articulation kinematics and wear of the Charité TDR. Implant wear was found to be insensitive to the CoR location, although seemingly non-physiologic endplate motion can result. Articulation and wear were biased significantly to the superior-bearing surface, even in the presence of significant perturbations of loading and friction. The computational wear model provides novel insight into the mechanics and wear of the Charité TDR, allowing for better interpretation of in vivo results, and giving useful insight for designing future laboratory physical tests.

  13. Highly preferential association of NonF508del CF mutations with the M470 allele.

    Science.gov (United States)

    Ciminelli, B M; Bonizzato, A; Bombieri, C; Pompei, F; Gabaldo, M; Ciccacci, C; Begnini, A; Holubova, A; Zorzi, P; Piskackova, T; Macek, M; Castellani, C; Modiano, G; Pignatti, P F

    2007-01-01

    On the basis of previous findings on random individuals, we hypothesized a preferential association of CF causing mutations with the M allele of the M470V polymorphic site of the CFTR gene. We have determined the M/V-CF mutation haplotype in a series of 201 North East Italian and 73 Czech CF patients who were not F508del homozygotes, as F508del was already known to be fully associated with the M allele. Out of 358 not F508del CF genes, 84 carried the V allele and 274 the less common M allele. In the N-E Italian population, MM subjects have a risk of carrying a CF causing mutation 6.9x greater than VV subjects when F508del is excluded and 15.4x when F508del is included. In the Czech population a similar, although less pronounced, association is observed. Besides the possible biological significance of this association, the possibility of exploiting it for a pilot screening program has been explored in a local North East Italian population for which CF patients were characterized for their CF mutation. General M470V genotyping followed by common CF mutation screening limited to couples in which each partner carries at least one M allele would need testing only 39% of the couples, which contribute 89% of the total risk, with a cost benefit.

  14. Preferential Concentration Of Solid Particles In Turbulent Horizontal Circular Pipe Flow

    Science.gov (United States)

    Kim, Jaehee; Yang, Kyung-Soo

    2017-11-01

    In particle-laden turbulent pipe flow, turbophoresis can lead to a preferential concentration of particles near the wall. To investigate this phenomenon, one-way coupled Direct Numerical Simulation (DNS) has been performed. Fully-developed turbulent pipe flow of the carrier fluid (air) is at Reτ = 200 based on the pipe radius and the mean friction velocity, whereas the Stokes numbers of the particles (solid) are St+ = 0.1 , 1 , 10 based on the mean friction velocity and the kinematic viscosity of the fluid. The computational domain for particle simulation is extended along the axial direction by duplicating the domain of the fluid simulation. By doing so, particle statistics in the spatially developing region as well as in the fully-developed region can be obtained. Accumulation of particles has been noticed at St+ = 1 and 10 mostly in the viscous sublayer, more intensive in the latter case. Compared with other authors' previous results, our results suggest that drag force on the particles should be computed by using an empirical correlation and a higher-order interpolation scheme even in a low-Re regime in order to improve the accuracy of particle simulation. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2015R1A2A2A01002981).

  15. Revisiting the origin of the preferential π-π stacking conformation of the (+)-8-phenylmenthyl acrylate

    International Nuclear Information System (INIS)

    Capim, Saulo L.; Santana, Sidney R.; Oliveira, Boaz G. de; Rocha, Gerd B.; Vasconcellos, Mario L.A.A

    2010-01-01

    In this paper we report a theoretical study aiming to revisit the origin of the preferential π-π stacking conformation of the (+)-8-phenylmenthyl acrylate (2). For this, we have applied several DFT and ab initio methods to calculate local minimum geometries, vibrational frequencies, thermochemical properties and 1 H NMR chemical shifts for 2 and the model compound 3-phenylpropyl acrylate (3). We have observed that the MPW1B95 functional was the most suitable method to explain 1 H NMR experimental data which show the stacking conformation of 2 (2S) is more stable that trans conformation (2T) and the stacking conformation of 3 (3S) is less stable that trans conformation (3T). After that, geometrical and energetic features of the intermolecular complex benzene...methylacrylate (4) have also been studied using MPW1B95 method. From our results, we have noticed that both steric and dispersion effects play a key role in the conformational equilibrium of 2. (author)

  16. Young macaques (Macaca fascicularis) preferentially bias attention towards closer, older, and better tool users.

    Science.gov (United States)

    Tan, Amanda W Y; Hemelrijk, Charlotte K; Malaivijitnond, Suchinda; Gumert, Michael D

    2018-05-12

    Examining how animals direct social learning during skill acquisition under natural conditions, generates data for examining hypotheses regarding how transmission biases influence cultural change in animal populations. We studied a population of macaques on Koram Island, Thailand, and examined model-based biases during interactions by unskilled individuals with tool-using group members. We first compared the prevalence of interactions (watching, obtaining food, object exploration) and proximity to tool users during interactions, in developing individuals (infants, juveniles) versus mature non-learners (adolescents, adults), to provide evidence that developing individuals are actively seeking information about tool use from social partners. All infants and juveniles, but only 49% of mature individuals carried out interacted with tool users. Macaques predominantly obtained food by scrounging or stealing, suggesting maximizing scrounging opportunities motivates interactions with tool users. However, while interactions by adults was limited to obtaining food, young macaques and particularly infants also watched tool users and explored objects, indicating additional interest in tool use itself. We then ran matrix correlations to identify interaction biases, and what attributes of tool users influenced these. Biases correlated with social affiliation, but macaques also preferentially targeted tool users that potentially increase scrounging and learning opportunities. Results suggest that social structure may constrain social learning, but the motivation to bias interactions towards tool users to maximize feeding opportunities may also socially modulate learning by facilitating close proximity to better tool users, and further interest in tool-use actions and materials, especially during development.

  17. Infective Juveniles of the Entomopathogenic Nematode Steinernema scapterisci Are Preferentially Activated by Cricket Tissue.

    Directory of Open Access Journals (Sweden)

    Dihong Lu

    Full Text Available Entomopathogenic nematodes are a subgroup of insect-parasitic nematodes that are used in biological control as alternatives or supplements to chemical pesticides. Steinernema scapterisci is an unusual member of the entomopathogenic nematode guild for many reasons including that it is promiscuous in its association with bacteria, it can reproduce in the absence of its described bacterial symbiont, and it is known to have a narrow host range. It is a powerful comparative model within the species and could be used to elucidate parasite specialization. Here we describe a new method of efficiently producing large numbers of S. scapterisci infective juveniles (IJs in house crickets and for quantifying parasitic activation of the IJs upon exposure to host tissue using morphological features. We found that parasite activation is a temporal process with more IJs activating over time. Furthermore, we found that activated IJs secrete a complex mixture of proteins and that S. scapterisci IJs preferentially activate upon exposure to cricket tissue, reaffirming the description of S. scapterisci as a cricket specialist.

  18. Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

    Science.gov (United States)

    Machiela, Mitchell J.; Zhou, Weiyin; Karlins, Eric; Sampson, Joshua N.; Freedman, Neal D.; Yang, Qi; Hicks, Belynda; Dagnall, Casey; Hautman, Christopher; Jacobs, Kevin B.; Abnet, Christian C.; Aldrich, Melinda C.; Amos, Christopher; Amundadottir, Laufey T.; Arslan, Alan A.; Beane-Freeman, Laura E.; Berndt, Sonja I.; Black, Amanda; Blot, William J.; Bock, Cathryn H.; Bracci, Paige M.; Brinton, Louise A.; Bueno-de-Mesquita, H Bas; Burdett, Laurie; Buring, Julie E.; Butler, Mary A.; Canzian, Federico; Carreón, Tania; Chaffee, Kari G.; Chang, I-Shou; Chatterjee, Nilanjan; Chen, Chu; Chen, Constance; Chen, Kexin; Chung, Charles C.; Cook, Linda S.; Crous Bou, Marta; Cullen, Michael; Davis, Faith G.; De Vivo, Immaculata; Ding, Ti; Doherty, Jennifer; Duell, Eric J.; Epstein, Caroline G.; Fan, Jin-Hu; Figueroa, Jonine D.; Fraumeni, Joseph F.; Friedenreich, Christine M.; Fuchs, Charles S.; Gallinger, Steven; Gao, Yu-Tang; Gapstur, Susan M.; Garcia-Closas, Montserrat; Gaudet, Mia M.; Gaziano, J. Michael; Giles, Graham G.; Gillanders, Elizabeth M.; Giovannucci, Edward L.; Goldin, Lynn; Goldstein, Alisa M.; Haiman, Christopher A.; Hallmans, Goran; Hankinson, Susan E.; Harris, Curtis C.; Henriksson, Roger; Holly, Elizabeth A.; Hong, Yun-Chul; Hoover, Robert N.; Hsiung, Chao A.; Hu, Nan; Hu, Wei; Hunter, David J.; Hutchinson, Amy; Jenab, Mazda; Johansen, Christoffer; Khaw, Kay-Tee; Kim, Hee Nam; Kim, Yeul Hong; Kim, Young Tae; Klein, Alison P.; Klein, Robert; Koh, Woon-Puay; Kolonel, Laurence N.; Kooperberg, Charles; Kraft, Peter; Krogh, Vittorio; Kurtz, Robert C.; LaCroix, Andrea; Lan, Qing; Landi, Maria Teresa; Marchand, Loic Le; Li, Donghui; Liang, Xiaolin; Liao, Linda M.; Lin, Dongxin; Liu, Jianjun; Lissowska, Jolanta; Lu, Lingeng; Magliocco, Anthony M.; Malats, Nuria; Matsuo, Keitaro; McNeill, Lorna H.; McWilliams, Robert R.; Melin, Beatrice S.; Mirabello, Lisa; Moore, Lee; Olson, Sara H.; Orlow, Irene; Park, Jae Yong; Patiño-Garcia, Ana; Peplonska, Beata; Peters, Ulrike; Petersen, Gloria M.; Pooler, Loreall; Prescott, Jennifer; Prokunina-Olsson, Ludmila; Purdue, Mark P.; Qiao, You-Lin; Rajaraman, Preetha; Real, Francisco X.; Riboli, Elio; Risch, Harvey A.; Rodriguez-Santiago, Benjamin; Ruder, Avima M.; Savage, Sharon A.; Schumacher, Fredrick; Schwartz, Ann G.; Schwartz, Kendra L.; Seow, Adeline; Wendy Setiawan, Veronica; Severi, Gianluca; Shen, Hongbing; Sheng, Xin; Shin, Min-Ho; Shu, Xiao-Ou; Silverman, Debra T.; Spitz, Margaret R.; Stevens, Victoria L.; Stolzenberg-Solomon, Rachael; Stram, Daniel; Tang, Ze-Zhong; Taylor, Philip R.; Teras, Lauren R.; Tobias, Geoffrey S.; Van Den Berg, David; Visvanathan, Kala; Wacholder, Sholom; Wang, Jiu-Cun; Wang, Zhaoming; Wentzensen, Nicolas; Wheeler, William; White, Emily; Wiencke, John K.; Wolpin, Brian M.; Wong, Maria Pik; Wu, Chen; Wu, Tangchun; Wu, Xifeng; Wu, Yi-Long; Wunder, Jay S.; Xia, Lucy; Yang, Hannah P.; Yang, Pan-Chyr; Yu, Kai; Zanetti, Krista A.; Zeleniuch-Jacquotte, Anne; Zheng, Wei; Zhou, Baosen; Ziegler, Regina G.; Perez-Jurado, Luis A.; Caporaso, Neil E.; Rothman, Nathaniel; Tucker, Margaret; Dean, Michael C.; Yeager, Meredith; Chanock, Stephen J.

    2016-01-01

    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases. PMID:27291797

  19. Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy

    CSIR Research Space (South Africa)

    Chimowa, George

    2017-06-01

    Full Text Available The preferential adsorption of NH(sub3) gas molecules on multi-walled carbon nanotubes (MWCNTs) was studied using in situ Raman spectroscopy. It was observed that the full widths at half maximum of the G band and the intensity ratio I(sub2D...

  20. Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)

    Science.gov (United States)

    Koch, Joshua C.; Ewing, Stephanie A.; Striegl, Robert G.; McKnight, Diane M.

    2013-01-01

    In high-latitude catchments where permafrost is present, runoff dynamics are complicated by seasonal active-layer thaw, which may cause a change in the dominant flowpaths as water increasingly contacts mineral soils of low hydraulic conductivity. A 2-year study, conducted in an upland catchment in Alaska (USA) underlain by frozen, well-sorted eolian silt, examined changes in infiltration and runoff with thaw. It was hypothesized that rapid runoff would be maintained by flow through shallow soils during the early summer and deeper preferential flow later in the summer. Seasonal changes in soil moisture, infiltration, and runoff magnitude, location, and chemistry suggest that transport is rapid, even when soils are thawed to their maximum extent. Between June and September, a shift occurred in the location of runoff, consistent with subsurface preferential flow in steep and wet areas. Uranium isotopes suggest that late summer runoff erodes permafrost, indicating that substantial rapid flow may occur along the frozen boundary. Together, throughflow and deep preferential flow may limit upland boreal catchment water and solute storage, and subsequently biogeochemical cycling on seasonal to annual timescales. Deep preferential flow may be important for stream incision, network drainage development, and the release of ancient carbon to ecosystems

  1. Law [Review of: World trade report 2011: the WTO and preferential trade agreements: from co-existence to coherence

    NARCIS (Netherlands)

    Mathis, J.H.

    2012-01-01

    The World Trade Review asked distinguished scholars from the three different fields of economics (Pravin Krishna), political science (Edward D. Mansfield) and law (James H. Mathis) to independently review the WTO's annual World Trade Report for 2011, the theme of which is The WTO and Preferential

  2. The Limits to Buying Stability in Tibet: Tibetan Representation and Preferentiality in China's Contemporary Public Employment System

    NARCIS (Netherlands)

    A.M. Fischer (Andrew Martín); A. Zenz (Adrian)

    2017-01-01

    textabstractBased on an entirely unexplored source of data, this paper analyses the evolution of Tibetan representation and preferentiality within public employment recruitment across all Tibetan areas from 2007 to 2015. While recruitment collapsed after the end of the job placement system (fenpei)

  3. Preferential processing of self-relevant stimuli occurs mainly at the perceptual and conscious stages of information processing.

    Science.gov (United States)

    Tacikowski, P; Ehrsson, H H

    2016-04-01

    Self-related stimuli, such as one's own name or face, are processed faster and more accurately than other types of stimuli. However, what remains unknown is at which stage of the information processing hierarchy this preferential processing occurs. Our first aim was to determine whether preferential self-processing involves mainly perceptual stages or also post-perceptual stages. We found that self-related priming was stronger than other-related priming only because of perceptual prime-target congruency. Our second aim was to dissociate the role of conscious and unconscious factors in preferential self-processing. To this end, we compared the "self" and "other" conditions in trials where primes were masked or unmasked. In two separate experiments, we found that self-related priming was stronger than other-related priming but only in the unmasked trials. Together, our results suggest that preferential access to the self-concept occurs mainly at the perceptual and conscious stages of the stimulus processing hierarchy. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Targeted detection of in vivo endogenous DNA base damage reveals preferential base excision repair in the transcribed strand.

    Science.gov (United States)

    Reis, António M C; Mills, Wilbur K; Ramachandran, Ilangovan; Friedberg, Errol C; Thompson, David; Queimado, Lurdes

    2012-01-01

    Endogenous DNA damage is removed mainly via base excision repair (BER), however, whether there is preferential strand repair of endogenous DNA damage is still under intense debate. We developed a highly sensitive primer-anchored DNA damage detection assay (PADDA) to map and quantify in vivo endogenous DNA damage. Using PADDA, we documented significantly higher levels of endogenous damage in Saccharomyces cerevisiae cells in stationary phase than in exponential phase. We also documented that yeast BER-defective cells have significantly higher levels of endogenous DNA damage than isogenic wild-type cells at any phase of growth. PADDA provided detailed fingerprint analysis at the single-nucleotide level, documenting for the first time that persistent endogenous nucleotide damage in CAN1 co-localizes with previously reported spontaneous CAN1 mutations. To quickly and reliably quantify endogenous strand-specific DNA damage in the constitutively expressed CAN1 gene, we used PADDA on a real-time PCR setting. We demonstrate that wild-type cells repair endogenous damage preferentially on the CAN1 transcribed strand. In contrast, yeast BER-defective cells accumulate endogenous damage preferentially on the CAN1 transcribed strand. These data provide the first direct evidence for preferential strand repair of endogenous DNA damage and documents the major role of BER in this process.

  5. Modelling the Preferential Solvation of Ferulic Acid in {2-Propanol (1 + Water (2} Mixtures at 298.15 K

    Directory of Open Access Journals (Sweden)

    Abolghasem Jouyban 1,2, Fleming Martínez 3 *

    2017-12-01

    Full Text Available Background: Recently Haq et al. reported the equilibrium solubility in {2-propanol (1 + water (2} mixtures at several temperatures with some numerical correlation analysis. Nevertheless, no attempt was made to evaluate the preferential solvation of this compound by the solvents. Methods: Preferential solvation of ferulic acid in the saturated mixtures at 298.15 K was analyzed based on the inverse Kirkwood-Buff integrals as described in the literature. Results: Ferulic acid is preferentially solvated by water in water-rich mixtures (0.00 < x1 < 0.19 but preferentially solvated by 2-propanol in mixtures with composition 0.19 < x1 < 1.00. Conclusion: These results could be interpreted as a consequence of hydrophobic hydration around the non-polar groups of the solute in the former case (0.00 < x1 < 0.19. Moreover, in the last case (0.19 < x1 < 1.00, the observed trend could be a consequence of the acid behavior of ferulic acid in front to 2-propanol molecules because this cosolvent is more basic than water as described by the respective solvatochromic parameters.

  6. Investigation on the combined operation of water gas shift and preferential oxidation reactor system on the kW scale

    NARCIS (Netherlands)

    O'Connell, M.; Kolb, G.A.; Schelhaas, K.P.; Schuerer, J.; Tiemann, D.; Keller, S.; Reinhard, D.; Hessel, V.

    2010-01-01

    A 5 kWel water gas shift reactor was integrated with a 5 kWel preferential oxidation reactor for the purposes of reducing the carbon monoxide levels in a reformate exit stream to levels below 100 ppm. The integrated system worked best at partial load with CO concentrations being reduced to 40 ppm at

  7. Growing Youth Growing Food: How Vegetable Gardening Influences Young People's Food Consciousness and Eating Habits

    Science.gov (United States)

    Libman, Kimberly

    2007-01-01

    Much attention is currently being paid to rising rates of obesity, especially among youth. In this context, garden-based education can have a role in improving public health. A qualitative study conducted at the Brooklyn Botanic Garden (BBG) Children's Garden provides supporting evidence for the claim that growing vegetables can improve the…

  8. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    Science.gov (United States)

    Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

    2012-01-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  9. Newly-fixed carbon preferentially flows through starch in the unicellular alga Rhodella

    International Nuclear Information System (INIS)

    Kroen, W.K.; Ramus, J.S.

    1989-01-01

    Cells of the unicellular red alga Rhodella reticulata produce copious amounts of anionic extracellular polysaccharides. Previous experiments, comparing growing and non-growing cells, showed little difference in the pattern of initial 14 C partitioning, with a high percentage of label in starch. Short labelling periods, followed by chasing in unlabelled medium, showed rapid movement of carbon through the starch pool within the first 6 hrs, with an accompanying increase in both the protein and mucilage fractions. The overall pattern of carbon metabolism appears fixed throughout growth of the cells, with total carbon input changing with changing growth phase. As starch is extrachloroplastic in the red algae, input of fixed carbon directly into the starch pool may serve as a routing mechanism to direct subsequent carbon metabolism within the cell

  10. Access to capital--a growing concern.

    Science.gov (United States)

    Carlson, Donald A

    2004-01-01

    Access to capital over the next ten years will be one of the biggest challenges healthcare organizations will face as they strive to remain competitive and serve their communities. Meeting the growing needs for capital will require a disciplined and honest assessment of the capital sources that will be available and the best ways of positioning an organization to maximize their uses. It is incumbent on chief executive officers and other senior leaders to create a disciplined process for allocating capital and conveying how that process will be linked to the organization's strategic plan. All of the credit constituencies "buying" healthcare need to fully understand how the organization is positioning itself for future growth and success, and detailed bond marketing plans need to be implemented well before the actual sale of a new bond issue. Large and small healthcare providers will have sufficient access to capital in the future if investors believe that senior hospital executives have a credible plan and are disciplined enough to execute it.

  11. High-purity germanium crystal growing

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1982-10-01

    The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10 10 cm - 3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers

  12. Selective sweeps in growing microbial colonies

    International Nuclear Information System (INIS)

    Korolev, Kirill S; Müller, Melanie J I; Murray, Andrew W; Nelson, David R; Karahan, Nilay; Hallatschek, Oskar

    2012-01-01

    Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction–diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction–diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays. (paper)

  13. Growing markets to sustain oil sands development

    International Nuclear Information System (INIS)

    Wise, T.H.

    2003-01-01

    The utilization of Alberta bitumen for the clean fuels market depends on upgrading, transportation, and refining processes. Forecasts show that oil sands production, which includes synthetic crude oil (SCO), will surpass declining conventional production in Western Canada. Several issues pose a challenge to the oil sands processing industry. The producers' market is affected by crude oil prices, market expansion options, diluent availability/cost, supply cost competitiveness, and regional processing. The common market issues include light/heavy crude prices, oil sands crude qualities, prices of oil sands crudes, pipeline infrastructure, and competitive supplies. The issues facing the refiners are: refining margins, security of crude supply, refined product quality, and competitive product supply. A brief review of markets for Canadian crude oil, including synthetic crude, was provided. The share of the Midwest market by Alberta must be retained and increased. The market expansion options were reviewed for both downstream (refining) and upstream (upgrading) operations. To reach more distant markets such as Southern Midwest, Washington, and California, new pipeline capacity would be required. The market is nearly saturated for Canada's heavy oil supply. More upgrading will be required as bitumen production increases. Market growth is still possible for Canada's SCO but according to forecasts, the market could also become saturated. To increase demand and allow supplies to grow, SCO prices may fall below light crude prices. It was noted that a balance must be achieved in order for producers to increase production and for refiner/upgraders to expand their conversion capacity. tabs., figs

  14. Selective sweeps in growing microbial colonies

    Science.gov (United States)

    Korolev, Kirill S.; Müller, Melanie J. I.; Karahan, Nilay; Murray, Andrew W.; Hallatschek, Oskar; Nelson, David R.

    2012-04-01

    Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction-diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction-diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays.

  15. Overlapping ETS and CRE Motifs (G/CCGGAAGTGACGTCA) Preferentially Bound by GABPα and CREB Proteins

    Science.gov (United States)

    Chatterjee, Raghunath; Zhao, Jianfei; He, Ximiao; Shlyakhtenko, Andrey; Mann, Ishminder; Waterfall, Joshua J.; Meltzer, Paul; Sathyanarayana, B. K.; FitzGerald, Peter C.; Vinson, Charles

    2012-01-01

    Previously, we identified 8-bps long DNA sequences (8-mers) that localize in human proximal promoters and grouped them into known transcription factor binding sites (TFBS). We now examine split 8-mers consisting of two 4-mers separated by 1-bp to 30-bps (X4-N1-30-X4) to identify pairs of TFBS that localize in proximal promoters at a precise distance. These include two overlapping TFBS: the ETS⇔ETS motif (C/GCCGGAAGCGGAA) and the ETS⇔CRE motif (C/GCGGAAGTGACGTCAC). The nucleotides in bold are part of both TFBS. Molecular modeling shows that the ETS⇔CRE motif can be bound simultaneously by both the ETS and the B-ZIP domains without protein-protein clashes. The electrophoretic mobility shift assay (EMSA) shows that the ETS protein GABPα and the B-ZIP protein CREB preferentially bind to the ETS⇔CRE motif only when the two TFBS overlap precisely. In contrast, the ETS domain of ETV5 and CREB interfere with each other for binding the ETS⇔CRE. The 11-mer (CGGAAGTGACG), the conserved part of the ETS⇔CRE motif, occurs 226 times in the human genome and 83% are in known regulatory regions. In vivo GABPα and CREB ChIP-seq peaks identified the ETS⇔CRE as the most enriched motif occurring in promoters of genes involved in mRNA processing, cellular catabolic processes, and stress response, suggesting that a specific class of genes is regulated by this composite motif. PMID:23050235

  16. Cellular location of rat muscle ferritins and their preferential loss during cell isolation.

    Science.gov (United States)

    Linder, M C; Roboz, M; McKown, M J; Pardridge, W M; Zak, R

    1984-04-10

    Heart and other muscles of the rat contain two forms of ferritin separable in polyacrylamide gel electrophoresis. The cellular location of the fast- and slow-migrating ferritins was investigated using primary cultures of hindlimb skeletal muscle, and isolated myocardial cell populations. Muscle and non-muscle cells were isolated in good yield from hearts of adult rats pretreated with large doses of iron to increase their ferritin content. In virtually all cases, the isolated muscle cells contained traces only of the fast-migrating species and the non-muscle cells contained small amounts of the slow-migrating ferritin. During cell isolation, 90-100% of both ferritins was lost and could be recovered in the perfusates and solutions employed, while one third of the total tissue protein, and a larger percentage of creatine phosphokinase, was recovered in the isolated cells. Primary cultures of thigh muscle from adult rats which had differentiated into multi-nucleated myotubes, were incubated for 1-3 days with chelated iron. These cells contained substantial amounts of the electrophoretically fast migrating ferritin, with its characteristic larger Stokes' radius (determined by quantitative polyacrylamide gel electrophoresis). None of the slow-migrating ferritin species was detected, although hindlimb muscle from iron-treated rats contained both forms. It is concluded that the fast-migrating ferritin of muscle, which is much larger and more asymmetric than other ferritins, is confined to the muscle cell population, while the other form is predominantly or exclusively in the non-muscle cells. Both ferritins are lost preferentially over other proteins during procedures which injure muscle tissue.

  17. Preferential recruitment of the basolateral amygdala during memory encoding of negative scenes in posttraumatic stress disorder.

    Science.gov (United States)

    Patel, Ronak; Girard, Todd A; Pukay-Martin, Nicole; Monson, Candice

    2016-04-01

    The vast majority of functional neuroimaging studies in posttraumatic stress disorder (PTSD) have examined the amygdala as a unitary structure. However, an emerging body of studies indicates that separable functions are subserved by discrete amygdala subregions. The basolateral subdivision (BLA), as compared with the centromedial amygdala (CMA), plays a unique role in learning and memory-based processes for threatening events, and alterations to the BLA have been implicated in the pathogenesis of PTSD. We assessed whether PTSD is associated with differential involvement of the BLA versus the CMA during successful encoding of emotionally charged events. Participants with PTSD (n=11) and a trauma-exposed comparison (TEC) group (n=11) viewed a series of photos that varied in valence (negative versus positive) and arousal (high versus low) while undergoing functional magnetic resonance imaging (fMRI). Subsequently, participants completed an old/new recognition memory test. Using analytic methods based on probabilistic cytoarchitectonic mapping, PTSD was associated with greater activation of the BLA, as compared to the CMA, during successful encoding of negative scenes, a finding which was not observed in the TEC group. Moreover, this memory-related activity in the BLA independently predicted PTSD status. Contrary to hypotheses, there was no evidence of altered BLA activity during memory encoding of high arousing relative to low arousing scenes. Task-related brain activation in PTSD does not appear to be consistent across the entire amygdala. Importantly, memory-related processing of negative information in PTSD is associated with preferential recruitment of the BLA. Copyright © 2016. Published by Elsevier Inc.

  18. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress.

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-07-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress.

  19. Zika virus preferentially replicates in the female reproductive tract after vaginal inoculation of rhesus macaques.

    Directory of Open Access Journals (Sweden)

    Timothy Carroll

    2017-07-01

    Full Text Available Zika virus (ZIKV is a mosquito-transmitted virus that can cause severe defects in an infected fetus. ZIKV is also transmitted by sexual contact, although the relative importance of sexual transmission is unclear. To better understand the role of sexual transmission in ZIKV pathogenesis, a nonhuman primate (NHP model of vaginal transmission was developed. ZIKV was readily transmitted to mature cycling female rhesus macaque (RM by vaginal inoculation with 104-106 plaque-forming units (PFU. However, there was variability in susceptibility between the individual RM with 1->8 vaginal inoculations required to establish infection. After treatment with Depoprovera, a widely used contraceptive progestin, two RM that initially resisted 8 vaginal ZIKV inoculations became infected after one ZIKV inoculation. Thus, Depoprovera seemed to enhance susceptibility to vaginal ZIKV transmission. Unexpectedly, the kinetics of virus replication and dissemination after intravaginal ZIKV inoculation were markedly different from RM infected with ZIKV by subcutaneous (SQ virus inoculation. Several groups have reported that after SQ ZIKV inoculation vRNA is rapidly detected in blood plasma with vRNA less common in urine and saliva and only rarely detected in female reproductive tract (FRT secretions. In contrast, in vaginally inoculated RM, plasma vRNA is delayed for several days and ZIKV replication in, and vRNA shedding from, the FRT was found in all 6 animals. Further, after intravaginal transmission ZIKV RNA shedding from FRT secretions was detected before or simultaneously with plasma vRNA, and persisted for at least as long. Thus, ZIKV replication in the FRT was independent of, and often preceded virus replication in the tissues contributing to plasma vRNA. These results support the conclusion that ZIKV preferentially replicates in the FRT after vaginal transmission, but not after SQ transmission, and raise the possibility that there is enhanced fetal infection and

  20. Importance of Pulmonary Vein Preferential Fibrosis for Atrial Fibrillation Promotion in Hypertensive Rat Hearts.

    Science.gov (United States)

    Iwasaki, Yu-Ki; Yamashita, Takeshi; Sekiguchi, Akiko; Hayami, Noriyuki; Shimizu, Wataru

    2016-06-01

    Hypertension is one of the independent risk factors for atrial fibrillation (AF). Pulmonary veins (PVs) play an important role as the substrate for AF and triggers of AF. The purpose of this study was to determine the structural remodelling of the PVs and its effect on promoting AF in hypertensive (HT) rat hearts. Eighteen-week-old Dahl salt-sensitive HT rats and their controls were used for histological and immunohistological analyses, and electrophysiological studies were performed in Langendorff perfused hearts. Masson-trichrome staining revealed that hypertension significantly increased the fibrosis in the PVs, particularly in subendocardial and perivascular areas, compared with that in control rats, however, at this early stage of hypertension, left atrial fibrosis was not prominent. In the HT rat hearts with PVs, electrical stimulation significantly increased the number of repetitive atrial firing and atrial tachycardia inducibility, which significantly diminished after the excision of the PVs. An immunofluorescent analysis revealed that HT rats had PV specific endocardial smooth muscle actin (αSMA)-positive cells with remarkable proliferation of platelet-derived growth factor (PDGF)-C and vascular endothelial growth factor (VEGF), which was lacking in the left atrial structures of the control and the HT rats. Pretreatment with imatinib, a PDGF receptor activity blocker, in HT rats reduced the αSMA-positive cell proliferation and fibrosis in the PVs and also induced a significant reduction in VEGF expression. Also, the drug pretreatment effectively prevented repetitive atrial firing promotion without affecting the blood pressure. PV preferential fibrosis might play an important role in the arrhythmogenic substrate of AF in HT rat hearts. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  1. An Empirical Investigation of Preferential Attachment Among Influential Members of a Large Artificial Community

    Directory of Open Access Journals (Sweden)

    JADERICK P. PABICO

    2014-02-01

    Full Text Available One among the many questions in social network analysis is how links form among members of Internet-mediated social network (ISN, where most members are usually anonymous, while link formation (i.e., interactions between members are facilitated only by non-personal communication technologies. Researchers offer preferential attachment (PA as a possible mechanism that can explain the behaviour of link formation, not only for real-world communities, but for artificial communities, such as ISNs, as well. PA suggests that members choose to be linked with members characterized with many links who are considered “central” to the community. This is because it is believed that central members can be relied to as a channel, if not the source themselves, of information, of wealth, or of any other kind of currency that the community is using. In this paper, the link formation process of members of one large ISN was examined to look for empirical evidences of PA among members who were clustered together according to the order of magnitude of their number of links at the global level. Members whose initial number of links that totals only up to ten thousand exhibit the opposite of PA, while members whose initial number of links that sums greater than ten thousand exhibit PA. This means that the lower bound for initial links for PA, at least for this particular ISN, is 10,000. Additionally, for those members whose link formation follow the PA mechanism, the order of magnitude of the rate of increase in their number of links is proportional to the order of magnitude of their initial number of links.

  2. Is attention based on spatial contextual memory preferentially guided by low spatial frequency signals?

    Science.gov (United States)

    Patai, Eva Zita; Buckley, Alice; Nobre, Anna Christina

    2013-01-01

    A popular model of visual perception states that coarse information (carried by low spatial frequencies) along the dorsal stream is rapidly transmitted to prefrontal and medial temporal areas, activating contextual information from memory, which can in turn constrain detailed input carried by high spatial frequencies arriving at a slower rate along the ventral visual stream, thus facilitating the processing of ambiguous visual stimuli. We were interested in testing whether this model contributes to memory-guided orienting of attention. In particular, we asked whether global, low-spatial frequency (LSF) inputs play a dominant role in triggering contextual memories in order to facilitate the processing of the upcoming target stimulus. We explored this question over four experiments. The first experiment replicated the LSF advantage reported in perceptual discrimination tasks by showing that participants were faster and more accurate at matching a low spatial frequency version of a scene, compared to a high spatial frequency version, to its original counterpart in a forced-choice task. The subsequent three experiments tested the relative contributions of low versus high spatial frequencies during memory-guided covert spatial attention orienting tasks. Replicating the effects of memory-guided attention, pre-exposure to scenes associated with specific spatial memories for target locations (memory cues) led to higher perceptual discrimination and faster response times to identify targets embedded in the scenes. However, either high or low spatial frequency cues were equally effective; LSF signals did not selectively or preferentially contribute to the memory-driven attention benefits to performance. Our results challenge a generalized model that LSFs activate contextual memories, which in turn bias attention and facilitate perception.

  3. Preferential localization of Lactococcus lactis cells entrapped in a caseinate/alginate phase separated system.

    Science.gov (United States)

    Léonard, Lucie; Gharsallaoui, Adem; Ouaali, Fahima; Degraeve, Pascal; Waché, Yves; Saurel, Rémi; Oulahal, Nadia

    2013-09-01

    This study aimed to entrap bioprotective lactic acid bacteria in a sodium caseinate/sodium alginate aqueous two-phase system. Phase diagram at pH=7 showed that sodium alginate and sodium caseinate were not miscible when their concentrations exceeded 1% (w/w) and 6% (w/w), respectively. The stability of the caseinate/alginate two-phase system was also checked at pH values of 6.0 and 5.5. Lactococcus lactis subsp. lactis LAB3 cells were added in a 4% (w/w) caseinate/1.5% (w/w) alginate two-phase system at pH=7. Fluorescence microscopy allowed to observe that the caseinate-rich phase formed droplets dispersed in a continuous alginate-rich phase. The distribution of bacteria in such a system was observed by epifluorescence microscopy: Lc. lactis LAB3 cells stained with Live/Dead(®) Baclight kit™ were located exclusively in the protein phase. Since zeta-potential measurements indicated that alginate, caseinate and bacterial cells all had an overall negative charge at pH 7, the preferential adhesion of LAB cells was assumed to be driven by hydrophobic effect or by depletion phenomena in such biopolymeric systems. Moreover, LAB cells viability was significantly higher in the ternary mixture obtained in the presence of both caseinate and alginate than in single alginate solution. Caseinate/alginate phase separated systems appeared thus well suited for Lc. lactis LAB3 cells entrapment. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Social influence on selection behaviour: Distinguishing local- and global-driven preferential attachment.

    Science.gov (United States)

    Pan, Xue; Hou, Lei; Liu, Kecheng

    2017-01-01

    Social influence drives human selection behaviours when numerous objects competing for limited attentions, which leads to the 'rich get richer' dynamics where popular objects tend to get more attentions. However, evidences have been found that, both the global information of the whole system and the local information among one's friends have significant influence over the one's selection. Consequently, a key question raises that, it is the local information or the global information more determinative for one's selection? Here we compare the local-based influence and global-based influence. We show that, the selection behaviour is mainly driven by the local popularity of the objects while the global popularity plays a supplementary role driving the behaviour only when there is little local information for the user to refer to. Thereby, we propose a network model to describe the mechanism of user-object interaction evolution with social influence, where the users perform either local-driven or global-driven preferential attachments to the objects, i.e., the probability of an objects to be selected by a target user is proportional to either its local popularity or global popularity. The simulation suggests that, about 75% of the attachments should be driven by the local popularity to reproduce the empirical observations. It means that, at least in the studied context where users chose businesses on Yelp, there is a probability of 75% for a user to make a selection according to the local popularity. The proposed model and the numerical findings may shed some light on the study of social influence and evolving social systems.

  5. Digestion of thyroglobulin with purified thyroid lysosomes: preferential release of iodoamino acids

    International Nuclear Information System (INIS)

    Tokuyama, T.; Yoshinari, M.; Rawitch, A.B.; Taurog, A.

    1987-01-01

    [ 131 I]Thyroglobulin [( 131 I]Tg), prepared by either enzymatic iodination of human goiter Tg in vitro or isolation from the thyroids of rats previously injected with 131 I, was digested with a solubilized enzyme mixture prepared from purified hog thyroid lysosomes. The digestion was performed at 37 C for 24 h under nitrogen at pH 5.0 in the presence of 4 mM dithiothreitol. Under these conditions the release of free [ 131 I] iodoamino acids (MIT, DIT, T4, and T3) was quantitatively very similar to that observed with a standard pronase digestion procedure. To determine whether other amino acids in Tg were released as quantitatively as the iodoamino acids, free amino acids in the lysosomal digest were measured, and total free amino acid release was compared with a similar analysis performed after digestion of [ 131 I]Tg with 6 N HCl. Total amino acid release was much less complete than iodoamino acid release, indicating preferential release of iodoamino acids from Tg by lysosomal digestion. Analysis of the lysosomal digest by HPLC on a size exclusion column indicated that Tg was degraded to peptides with a mol wt less than 4000. Assuming that the in vitro lysosomal digestion system represents a valid model for the physiological proteolytic system that degrades Tg, the results of the present study suggest that a substantial portion of the Tg in the thyroid is not degraded to free amino acids and that peptide fragments of Tg are normally present in the thyroid. In such a case, the fate and possible physiological activity of these fragments require further elucidation

  6. The determination of radioactive strontium in environmental samples by preferential ion exchange separation from calcium

    International Nuclear Information System (INIS)

    Fukushima, Hiroto; Nonaka, Nobuhiro; Honda, Tetsutaro; Kimura, Toshimasa; Higuchi, Hideo

    1979-01-01

    The determination of radioactive strontium in environmental samples involves a difficulty in the separation and purification of strontium from large amounts of calcium. The principal technique employed in this study is based on a cation exchange separation after preferential chelation of calcium over strontium by EDTA. The alkaline earth fraction separated from samples is dissolved in 1.2 M HCl and an equivalent amount of EDTA is added. The solution is passed through a Dowex 50W-X8 ion exchange column at a flow rate of 20 ml/min after the pH has been adjusted to 5.1. A fraction of calcium retained on the resin is eluted out with 1.8 l of 2 w/v% EDTA solution at pH 5.1. Then the strontium is eluted with 450 ml of 2 M HCl. The strontium carbonate is precipitated, and the chemical yield is determined. After standing for 14 days to reach the radioactive equilibrium of 90 Sr - 90 Y, the activity of 89 Sr + 90 Sr + 90 Y is measured. Then the activity of 90 Sr + 90 Y is measured by milking the 90 Y. The proposed procedure has been applied to sea water, soil and various ash samples of vegetables, seaweeds and daily foods. The results obtained are in good agreement with those by a classical fuming nitric acid precipitation method. The detection limits are 0.1 pCi/l for 10 l of sea water, 10 pCi/kg for 100 g of soil and 1 pCi/kg-fresh for 20 g ash samples, respectively. (author)

  7. Zika virus preferentially replicates in the female reproductive tract after vaginal inoculation of rhesus macaques.

    Science.gov (United States)

    Carroll, Timothy; Lo, Ming; Lanteri, Marion; Dutra, Joseph; Zarbock, Katie; Silveira, Paola; Rourke, Tracy; Ma, Zhong-Min; Fritts, Linda; O'Connor, Shelby; Busch, Michael; Miller, Christopher J

    2017-07-01

    Zika virus (ZIKV) is a mosquito-transmitted virus that can cause severe defects in an infected fetus. ZIKV is also transmitted by sexual contact, although the relative importance of sexual transmission is unclear. To better understand the role of sexual transmission in ZIKV pathogenesis, a nonhuman primate (NHP) model of vaginal transmission was developed. ZIKV was readily transmitted to mature cycling female rhesus macaque (RM) by vaginal inoculation with 104-106 plaque-forming units (PFU). However, there was variability in susceptibility between the individual RM with 1->8 vaginal inoculations required to establish infection. After treatment with Depoprovera, a widely used contraceptive progestin, two RM that initially resisted 8 vaginal ZIKV inoculations became infected after one ZIKV inoculation. Thus, Depoprovera seemed to enhance susceptibility to vaginal ZIKV transmission. Unexpectedly, the kinetics of virus replication and dissemination after intravaginal ZIKV inoculation were markedly different from RM infected with ZIKV by subcutaneous (SQ) virus inoculation. Several groups have reported that after SQ ZIKV inoculation vRNA is rapidly detected in blood plasma with vRNA less common in urine and saliva and only rarely detected in female reproductive tract (FRT) secretions. In contrast, in vaginally inoculated RM, plasma vRNA is delayed for several days and ZIKV replication in, and vRNA shedding from, the FRT was found in all 6 animals. Further, after intravaginal transmission ZIKV RNA shedding from FRT secretions was detected before or simultaneously with plasma vRNA, and persisted for at least as long. Thus, ZIKV replication in the FRT was independent of, and often preceded virus replication in the tissues contributing to plasma vRNA. These results support the conclusion that ZIKV preferentially replicates in the FRT after vaginal transmission, but not after SQ transmission, and raise the possibility that there is enhanced fetal infection and pathology

  8. Active and Passive 3D Vector Radiative Transfer with Preferentially-Aligned Ice Particles

    Science.gov (United States)

    Adams, I. S.; Munchak, S. J.; Pelissier, C.; Kuo, K. S.; Heymsfield, G. M.

    2017-12-01

    To support the observation of clouds and precipitation using combinations of radars and radiometers, a forward model capable of representing diverse sensing geometries for active and passive instruments is necessary for correctly interpreting and consistently combining multi-sensor measurements from ground-based, airborne, and spaceborne platforms. As such, the Atmospheric Radiative Transfer Simulator (ARTS) uses Monte Carlo integration to produce radar reflectivities and radiometric brightness temperatures for three-dimensional cloud and precipitation input fields. This radiative transfer framework is capable of efficiently sampling Gaussian antenna beams and fully accounting for multiple scattering. By relying on common ray-tracing tools, gaseous absorption models, and scattering properties, the model reproduces accurate and consistent radar and radiometer observables. While such a framework is an important component for simulating remote sensing observables, the key driver for self-consistent radiative transfer calculations of clouds and precipitation is scattering data. Research over the past decade has demonstrated that spheroidal models of frozen hydrometeors cannot accurately reproduce all necessary scattering properties at all desired frequencies. The discrete dipole approximation offers flexibility in calculating scattering for arbitrary particle geometries, but at great computational expense. When considering scattering for certain pristine ice particles, the Extended Boundary Condition Method, or T-Matrix, is much more computationally efficient; however, convergence for T-Matrix calculations fails at large size parameters and high aspect ratios. To address these deficiencies, we implemented the Invariant Imbedding T-Matrix Method (IITM). A brief overview of ARTS and IITM will be given, including details for handling preferentially-aligned hydrometeors. Examples highlighting the performance of the model for simulating space-based and airborne measurements

  9. Preferential retrotransposition in aging yeast mother cells is correlated with increased genome instability.

    Science.gov (United States)

    Patterson, Melissa N; Scannapieco, Alison E; Au, Pak Ho; Dorsey, Savanna; Royer, Catherine A; Maxwell, Patrick H

    2015-10-01

    Retrotransposon expression or mobility is increased with age in multiple species and could promote genome instability or altered gene expression during aging. However, it is unclear whether activation of retrotransposons during aging is an indirect result of global changes in chromatin and gene regulation or a result of retrotransposon-specific mechanisms. Retromobility of a marked chromosomal Ty1 retrotransposon in Saccharomyces cerevisiae was elevated in mother cells relative to their daughter cells, as determined by magnetic cell sorting of mothers and daughters. Retromobility frequencies in aging mother cells were significantly higher than those predicted by cell age and the rate of mobility in young populations, beginning when mother cells were only several generations old. New Ty1 insertions in aging mothers were more strongly correlated with gross chromosome rearrangements than in young cells and were more often at non-preferred target sites. Mother cells were more likely to have high concentrations and bright foci of Ty1 Gag-GFP than their daughter cells. Levels of extrachromosomal Ty1 cDNA were also significantly higher in aged mother cell populations than their daughter cell populations. These observations are consistent with a retrotransposon-specific mechanism that causes retrotransposition to occur preferentially in yeast mother cells as they begin to age, as opposed to activation by phenotypic changes associated with very old age. These findings will likely be relevant for understanding retrotransposons and aging in many organisms, based on similarities in regulation and consequences of retrotransposition in diverse species. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Acrolein preferentially damages nucleolus eliciting ribosomal stress and apoptosis in human cancer cells.

    Science.gov (United States)

    Wang, Hsiang-Tsui; Chen, Tzu-Ying; Weng, Ching-Wen; Yang, Chun-Hsiang; Tang, Moon-Shong

    2016-12-06

    Acrolein (Acr) is a potent cytotoxic and DNA damaging agent which is ubiquitous in the environment and abundant in tobacco smoke. Acr is also an active cytotoxic metabolite of the anti-cancer drugs cyclophosphamide and ifosfamide. The mechanisms via which Acr exerts its anti-cancer activity and cytotoxicity are not clear. In this study, we found that Acr induces cytotoxicity and cell death in human cancer cells with different activities of p53. Acr preferentially binds nucleolar ribosomal DNA (rDNA) to form Acr-deoxyguanosine adducts, and induces oxidative damage to both rDNA and ribosomal RNA (rRNA). Acr triggers ribosomal stress responses, inhibits rRNA synthesis, reduces RNA polymerase I binding to the promoter of rRNA gene, disrupts nucleolar integrity, and impairs ribosome biogenesis and polysome formation. Acr causes an increase in MDM2 levels and phosphorylation of MDM2 in A549 and HeLa cells which are p53 active and p53 inactive, respectively. It enhances the binding of ribosomal protein RPL11 to MDM2 and reduces the binding of p53 and E2F-1 to MDM2 resulting in stabilization/activation of p53 in A549 cells and degradation of E2F-1 in A549 and HeLa cells. We propose that Acr induces ribosomal stress which leads to activation of MDM2 and RPL11-MDM2 binding, consequently, activates p53 and enhances E2F-1 degradation, and that taken together these two processes induce apoptosis and cell death.

  11. Preferential loss of dorsal-hippocampus synapses underlies memory impairments provoked by short, multimodal stress

    Science.gov (United States)

    Maras, P M; Molet, J; Chen, Y; Rice, C; Ji, S G; Solodkin, A; Baram, T Z

    2014-01-01

    The cognitive effects of stress are profound, yet it is unknown if the consequences of concurrent multiple stresses on learning and memory differ from those of a single stress of equal intensity and duration. We compared the effects on hippocampus-dependent memory of concurrent, hours-long light, loud noise, jostling and restraint (multimodal stress) with those of restraint or of loud noise alone. We then examined if differences in memory impairment following these two stress types might derive from their differential impact on hippocampal synapses, distinguishing dorsal and ventral hippocampus. Mice exposed to hours-long restraint or loud noise were modestly or minimally impaired in novel object recognition, whereas similar-duration multimodal stress provoked severe deficits. Differences in memory were not explained by differences in plasma corticosterone levels or numbers of Fos-labeled neurons in stress-sensitive hypothalamic neurons. However, although synapses in hippocampal CA3 were impacted by both restraint and multimodal stress, multimodal stress alone reduced synapse numbers severely in dorsal CA1, a region crucial for hippocampus-dependent memory. Ventral CA1 synapses were not significantly affected by either stress modality. Probing the basis of the preferential loss of dorsal synapses after multimodal stress, we found differential patterns of neuronal activation by the two stress types. Cross-correlation matrices, reflecting functional connectivity among activated regions, demonstrated that multimodal stress reduced hippocampal correlations with septum and thalamus and increased correlations with amygdala and BST. Thus, despite similar effects on plasma corticosterone and on hypothalamic stress-sensitive cells, multimodal and restraint stress differ in their activation of brain networks and in their impact on hippocampal synapses. Both of these processes might contribute to amplified memory impairments following short, multimodal stress. PMID:24589888

  12. Using Smoke Injection in Drains to Identify Potential Preferential Pathways in a Drained Arable Field

    Science.gov (United States)

    Nielsen, M. H.; Petersen, C. T.; Hansen, S.

    2014-12-01

    Macropores forming a continuous pathway between the soil surface and subsurface drains favour the transport of many contaminants from agricultural fields to surface waters. The smoke injection method presented by Shipitalo and Gibbs (2000) used for demonstrating and quantifying such pathways has been further developed and used on a drained Danish sandy loam. In order to identify the preferential pathways to drains, smoke was injected in three 1.15 m deep tile drains (total drain length 93 m), and smoke emitting macropores (SEMP) at the soil surface were counted and characterized as producing either strong or weak plumes compared to reference plumes from 3 and 6 mm wide tubes. In the two situations investigated in the present study - an early spring and an autumn situation, smoke only penetrated the soil surface layer via earthworm burrows located in a 1.0 m wide belt directly above the drain lines. However, it is known from previous studies that desiccation fractures in a dry summer situation also can contribute to the smoke pattern. The distance between SEMP measured along the drain lines was on average 0.46 m whereas the average spacing between SEMP with strong plumes was 2.3 m. Ponded water was applied in 6 cm wide rings placed above 52 burrows including 17 reference burrows which did not emit smoke. Thirteen pathways in the soil were examined using dye tracer and profile excavation. SEMP with strong plumes marked the entrance of highly efficient transport pathways conducting surface applied water and dye tracer into the drain. However, no single burrow was traced all the way from the surface into the drain, the dye patterns branched off in a network of other macropores. Water infiltration rates were significantly higher (P drains and surface waters, pathways being associated primarily with unevenly distributed SEMP producing strong smoke plumes.

  13. Carcass traits and meat quality of different slow growing and fast growing broiler chickens

    Directory of Open Access Journals (Sweden)

    M. Oblakova

    2017-12-01

    Full Text Available Abstract. The experiment was conducted in the breeder farm of department Population genetics, reproduction and technologies of poultry and rabbits at the Agriculture Institute of Stara Zagora. Five lines from the National Gene Pool of Bulgaria: line Ss (Sussex, line E (Barred Plymouth Rock, line NG (New Hampshire, line F (NG x Red Rhode Island, line L (White Plymouth Rock were used as maternal forms in the crossing schedule and line M (Cornish as a paternal form for production of slow-growing broilers. The birds were grown to 84 days. Feeding was done with compound feeds according to the age: starter (1/14 days of age, grower (14/28 days of age, finisher (28/84 days of age. By the end of the experiment, slaughter analysis was performed with 3 female and 3 male broiler chickens per group with live weight corresponding to the average of each genotype. The live weight was determined, as well as the grill weight, the weights of cuts (breast, thighs, wings, edible offal (heart, liver, gizzard and abdominal fat. On the basis of these data, the slaughter yield and body parts ratios were calculated. The data for the live body weights of birds at slaughtering indicated the highest values for group V – 4040g, followed by groups ІV and ІІ – 3271.67g and 3186.67g, respectively (p<0.05. There was a statistically significant difference between the sexes with superiority of male birds (p<0.001. In the other 3 groups, breast meat percentage ranged from 19.48 to 19.84%. The share of thighs from the grill was the greatest in slow-growing chickens from group II – 33.01%, followed by group І – 32.35%, group IV – 32.18%, and the lowest- in groups ІІІ and V (31.91% and 31.18%, respectively. The analysis of data exhibited a significant effect of the genotype on water content of breast meat (resp. Dry matter, with lower values in slow-growing birds from group III – 73.19% (p<0.05, whereas in the other groups it ranged between 73.44 and 73.62%. The

  14. Non-Selective Evolution of Growing Populations.

    Directory of Open Access Journals (Sweden)

    Karl Wienand

    Full Text Available Non-selective effects, like genetic drift, are an important factor in modern conceptions of evolution, and have been extensively studied for constant population sizes (Kimura, 1955; Otto and Whitlock, 1997. Here, we consider non-selective evolution in the case of growing populations that are of small size and have varying trait compositions (e.g. after a population bottleneck. We find that, in these conditions, populations never fixate to a trait, but tend to a random limit composition, and that the distribution of compositions "freezes" to a steady state. This final state is crucially influenced by the initial conditions. We obtain these findings from a combined theoretical and experimental approach, using multiple mixed subpopulations of two Pseudomonas putida strains in non-selective growth conditions (Matthijs et al, 2009 as model system. The experimental results for the population dynamics match the theoretical predictions based on the Pólya urn model (Eggenberger and Pólya, 1923 for all analyzed parameter regimes. In summary, we show that exponential growth stops genetic drift. This result contrasts with previous theoretical analyses of non-selective evolution (e.g. genetic drift, which investigated how traits spread and eventually take over populations (fixate (Kimura, 1955; Otto and Whitlock, 1997. Moreover, our work highlights how deeply growth influences non-selective evolution, and how it plays a key role in maintaining genetic variability. Consequently, it is of particular importance in life-cycles models (Melbinger et al, 2010; Cremer et al, 2011; Cremer et al, 2012 of periodically shrinking and expanding populations.

  15. Protein synthesis in the growing rat lung

    International Nuclear Information System (INIS)

    Kelley, J.; Chrin, L.

    1986-01-01

    Developmental control of protein synthesis in the postnatal growth of the lung has not been systematically studied. In male Fischer 344 rats, lung growth continues linearly as a function of body weight (from 75 to 450 g body weight). To study total protein synthesis in lungs of growing rats, we used the technique of constant intravenous infusion of tritiated leucine, an essential amino acid. Lungs of sacrificed animals were used to determine the leucine incorporation rate into newly synthesized protein. The specific radioactivity of the leucine associated with tRNA extracted from the same lungs served as an absolute index of the precursor leucine pool used for lung protein synthesis. On the basis of these measurements, we were able to calculate the fractional synthesis rate (the proportion of total protein destroyed and replaced each day) of pulmonary proteins for each rat. Under the conditions of isotope infusion, leucyl-tRNA very rapidly equilibrates with free leucine of the plasma and of the extracellular space of the lung. Infusions lasting 30 minutes or less yielded linear rates of protein synthesis without evidence of contamination of lung proteins by newly labeled intravascular albumin. The fractional synthesis rate is considerably higher in juvenile animals (55% per day) than in adult rats (20% per day). After approximately 12 weeks of age, the fractional synthesis rate remains extremely constant in spite of continued slow growth of the lung. It is apparent from these data that in both young and adult rats the bulk of total protein synthesis is devoted to rapidly turning over proteins and that less than 4 percent of newly made protein is committed to tissue growth

  16. The growing need for analytical quality control

    International Nuclear Information System (INIS)

    Suschny, O.; Richman, D.M.

    1974-01-01

    Technological development in a country is directly dependent upon its analytical chemistry or measurement capability, because it is impossible to achieve any level of technological sophistication without the ability to measure. Measurement capability is needed to determine both technological competence and technological consequence. But measurement itself is insufficient. There must be a standard or a reference for comparison. In the complicated world of chemistry the need for reference materials grows with successful technological development. The International Atomic Energy Agency has been distributing calibrated radioisotope solutions, standard reference materials and intercomparison materials since the early 1960's. The purpose of this activity has been to help laboratories in its Member States to assess and, if necessary, to improve the reliability of their analytical work. The value and continued need of this service has been demonstrated by the results of many intercomparisons which proved that without continuing analytical quality control activities, adequate reliability of analytical data could not be taken for granted. Analytical chemistry, lacking the glamour of other aspects of the physical sciences, has not attracted the attention it deserves, but in terms of practical importance, it warrants high priority in any developing technological scheme, because without it there is little chance to evaluate technological success or failure or opportunity to identify the reasons for success or failure. The scope and the size of the future programme of the IAEA in this field has been delineated by recommendations made by several Panels of Experts; all have agreed on the importance of this programme and made detailed recommendations in their areas of expertise. The Agency's resources are limited and it cannot on its own undertake the preparation and distribution of all the materials needed. It can, however, offer a focal point to bring together different

  17. Ultrastructural differences between wall apices of growing and non-growing hyphae of Schizophyllum commune

    International Nuclear Information System (INIS)

    Vermeulen, C.A.; Wessels, J.G.H.

    1984-01-01

    Newly synthesized chitin at the hyphal apex of Schizophyllum commune was shown to be highly susceptible to chitinase degradiation and solubilization by dilute mineral acid. With time this chitin became gradually more resistant to these treatments. With a combination of the shadow-cast technique and electron microscopic autoradiography it could be shown that this process occurred as the newly synthesized chitin moved into subapical parts of growing hyphae but also in non-growing apices which had ceased growth after incorporation of the N-acetyl[6- 3 H]glucosamine. These results are in agreement with a model which explains apical morphogenesis by assuming that the newly synthesized wall material at the apex is plastic due to the presence of individual polymer chains but becomes rigidified because of subsequent physical and chemical changes involving these polymers. (Author)

  18. Growth performance, haematology and cost benefit of growing ...

    African Journals Online (AJOL)

    Growing rabbits on 24-h feed access time (control) recorded a higher (p0.05) across the feed access time and restriction duration. White blood cell was higher in growing rabbits on 2-h feed access ...

  19. A growing danger: the risks posed by marihuana grow-ops

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, F. [Canadian Electricity Association (Canada)

    2005-02-01

    The proliferation of sophisticated illegal indoor multi-plant marihuana cultivation operations is discussed, focusing primarily on public health and safety issues. Public health issues arise from the high level of molds and pollens caused by high humidity, which can cause asthma, respiratory conditions and allergies, particularly among children, and the likelihood of deadly levels of carbon monoxide build-up resulting from faulty rerouting of the residence's ventilation system. Safety issues discussed are: fires and electrocutions associated with the use of electrical diversions or bipasses to circumvent utility meters, the chemical and electrical hazards involved in investigating and dismantling growing operations, the significant dangers to utility crews who must repair illegal electrical bypasses, injuries by the booby-traps planted to protect the operation from other criminals or law enforcement agents, and the physical danger from the violence, including homicide and assaults, carried out by operators to exert control over production and distribution. Although in general, there is a relaxed attitude towards marihuana use in Canada. there is growing evidence of increasing public concern over large-scale growing operations. Nevertheless, to date operators of grow-ops have been dealt with lightly by the justice system. For example, in British Columbia 11,733 cases have come to the attention of police during the 1997 to 2000 period. Of these about half were dealt with informally (i.e. 'no case' seizures) and 2,255 cases led to at least one offender being convicted. The majority of convictions did not result in custodial dispositions. Only 18 per cent of the cases resulted in prison sentences, the average term being only 4.5 months.

  20. Chemical composition of metapleural gland secretions of fungus-growing and non-fungus-growing ants.

    Science.gov (United States)

    Vieira, Alexsandro S; Morgan, E David; Drijfhout, Falko P; Camargo-Mathias, Maria I

    2012-10-01

    The metapleural gland is exclusive to ants, and unusual among exocrine glands in having no mechanism for closure and retention of secretion. As yet, no clear conclusion has been reached as to the function of metapleural gland secretion. Metapleural gland secretions were investigated for fungus-growing ants representing the derived attines Trachymyrmex fuscus, Atta laevigata, and Acromyrmex coronatus, the basal attines Apterostigma pilosum and Mycetarotes parallelus, and non-fungus-growing ants of the tribes Ectatommini (Ectatomma brunneum) and Myrmicini (Pogonomyrmex naegeli). Our results showed that the secretions of leaf-cutting ants (A. laevigata and A. coronatus) and the derived attine, T. fuscus, contain a greater variety and larger quantities of volatile compounds than those of myrmicine and ectatommine ants. The most abundant compounds found in the metapleural glands of A. laevigata and A. coronatus were hydroxyacids, and phenylacetic acid (only in A. laevigata). Indole was present in all groups examined, while skatole was found in large quantities only in attines. Ketones and aldehydes are present in the secretion of some attines. Esters are present in the metapleural gland secretion of all species examined, although mainly in A. laevigata, A. coronatus, and T. fuscus. Compared with basal attines and non-fungus-growing ants, the metapleural glands of leaf-cutting ants produce more acidic compounds that may have an antibiotic or antifungal function.

  1. WSGB: A Web Service-Based Growing Book

    Science.gov (United States)

    Dow, C. R.; Huang, L. H.; Chen, K. H.; Chiu, J. C.; Lin, C. M.

    2006-01-01

    Growing Book refers to an electronic textbook that is co-developed, and has the ability to be constantly maintained, by groups of independent authors, thus creating a rich and ever-growing learning environment that can be conveniently accessible from anywhere. This work designs and implements a Web Service-based Growing Book that has the merits of…

  2. Estimation and upscaling of dual-permeability model parameters for the transport of E.coli D21g in soils with preferential flow

    Science.gov (United States)

    Dual-permeability models are increasingly used to quantify the transport of solutes and microorganisms in soils with preferential flow. An ability to accurately determine the model parameters and their variation with preferential pathway characteristics is crucial for predicting the transport of mi...

  3. Identification of protozoa in dairy lagoon wastewater that consume Escherichia coli O157:H7 preferentially.

    Directory of Open Access Journals (Sweden)

    Subbarao V Ravva

    Full Text Available Escherichia coli O157:H7 (EcO157, an agent of life threatening hemolytic-uremic syndrome, resides in ruminants and is released in feces at numbers as high as 10 million cells/gram. EcO157 could survive in manure for as long as 21 months, but we observed a 90% decrease in cells of an outbreak strain of EcO157 within half a day in wastewater from dairy lagoons. Although chemical, environmental and biological factors may be responsible for this decrease, we observed an 11-fold increase in native protozoa when wastewater was re-inoculated with 2×10(7 cells of EcO157/mL. These protozoa engulfed the green fluorescent protein labeled EcO157 within 2 hours after inoculation, but expelled vacuoles filled with live EcO157 cells within 3 days into surrounding wastewater, whereas other protozoa retained the EcO157-filled vacuoles for 7 days. EcO157 was not detected by confocal microscopy either inside or outside protozoa after 7 days. Mixed cultures of protozoa enriched from wastewater consumed EcO157 preferentially as compared to native aerobic bacteria, but failed to eliminate them when EcO157 cells declined to 10(4/mL. We isolated three protozoa from mixed cultures and typed them by 18S sequencing as Vorticella microstoma, Platyophyra sp. and Colpoda aspera. While all three protozoa internalized EcO157, only Platyophyra and Colpoda acted as predators. Similar to mixed cultures, these protozoa failed to eliminate EcO157 from PBS containing no other supplemental nutrients or prey. However, spiking PBS with cereal grass medium as nutrients induced predation of EcO157 by Platyophyra sp. after 3 days or enhanced predation by Colpoda after 5 days. Therefore, attempts to enrich protozoa to decrease EcO157 from dairy lagoons, may correspond to an increase in protozoa similar to Vorticella and possibly facilitate transport of bacterial pathogens to food crops grown in proximity.

  4. Movement of Cryptosporidium parvum Oocysts through Soils without Preferential Pathways: Exploratory Test

    Directory of Open Access Journals (Sweden)

    Christophe J. G. Darnault

    2017-06-01

    Full Text Available Groundwater contamination by oocysts of the waterborne pathogen Cryptosporidium parvum is a significant cause of animal and human disease worldwide. Although research has been undertaken in the past to determine how specific physical and chemical properties of soils affect the risk of groundwater contamination by C. parvum, there is as yet no clear conclusion concerning the range of mobility of C. parvum that one should expect in field soils. In this context, the key objective of this research was to determine the magnitude of C. parvum transport in a number of soils, under conditions in which fast and preferential transport has been successfully prevented. C. parvum oocysts were applied at the surface of different soils and subjected to artificial rainfall. Apparently for the first time, quantitative PCR was used to detect and enumerate oocysts in the soil columns and in the leachates. The transport of oocysts by infiltrating water, and the considerable retention of oocysts in soil was demonstrated for all soils, although differences in the degree of transport were observed with soils of different types. More oocysts were found in leachates from sandy loam soils than in leachates from loamy sand soils and the retention of oocysts in different soils did not significantly differ. The interaction of various processes of the hydrologic system and biogeochemical mechanisms contributed to the transport of oocysts through the soil matrix. Results suggest that the interplay of clay, organic matter, and Ca2+ facilitates and mediates the transfer of organic matter from mineral surfaces to oocysts surface, resulting in the enhanced breakthrough of oocysts through matrices of sandy loam soils compared to those of loamy sand soils. Although the number of occysts that penetrate the soil matrix account for only a small percentage of initial inputs, they still pose a significant threat to human health, especially in groundwater systems with a water table not

  5. Mouse preferential incising force orientation changes during jaw closing muscle hyperalgesia and is sex dependent.

    Science.gov (United States)

    Widmer, C G; Morris-Wiman, J

    2016-12-01

    Mouse incising is controlled by a central pattern generator and this activity can change in the presence of pain. The incising frequency and maximum force generation decreases with pain. In this study, we used repetitive acidic injections in the left masseter muscle of male and female mice to determine differences between baseline and jaw muscle pain conditions and the effect of sex on preferential incising direction. A within subject design was used to evaluate data previously acquired using multi-axis force data (X, Y and Z) from the 4th baseline recording day and day 7 post-injection (day of maximal pain response) for each mouse of each sex. A total of 34 female and male (age 3-9months) CD-1 mice were evaluated. After mathematically rotating the X and Y axes to align the Y axis to be parallel to the wire struts of the cage top, data were analyzed to determine incising direction preference during baseline (non-pain) and pain (day 7) conditions and between sex. Radar plots of X-Y, X-Z and Y-Z axes depicted the average direction of incising preference between baseline and pain conditions for each sex. Statistical differences among groups were tested using a mixed model ANOVA. Similar to previous findings, female mice had a more robust difference in incising direction preference when comparing male and female pain conditions and this was most evident in the X-Z axes. The incising frequencies most commonly affected were 5.3, 6.2 and 7.6Hz. Male mice varied little in their incising direction preference between the baseline and pain conditions. In addition, statistical comparison of ratios of the percent of time spent incising in the Z versus X axes for each incising frequency found that the incising preference was not different when comparing 5.3 and 7.6Hz frequencies. Finally, female mice used a novel approach to minimize pain while incising by rotating their head and body nearly 180 degrees while males did not use this strategy as frequently. The preferred incising

  6. Effects of subsoil compaction on hydraulic properties and preferential flow in a Swedish clay soil

    DEFF Research Database (Denmark)

    Mossadeghi-Björklund, M; Arvidsson, J.; Keller, Thomas

    2016-01-01

    in saturated hydraulic conductivity, air permeability and number of macropores at the second site. At this site, the traffic also significantly reduced the strength of preferential flow, presumably due to compaction-induced disruption of macropore continuity. In apparent contrast, some previous studies have shown......Soil compaction by vehicular traffic modifies the pore structure and soil hydraulic properties. These changes potentially influence the occurrence of preferential flow, which so far has been little studied. Our aim was to study the effect of compaction on soil hydraulic and transport properties...... transport derived from non-reactive tracer breakthrough curves and measurements of saturated hydraulic conductivity (Ks) and air permeability at the field moisture content (Ka). Although the traffic treatment did not cause any compaction effects at one of the two sites, it did result in significant reductions...

  7. A Growing Anticline in Tainan City, Taiwan

    Science.gov (United States)

    Lee, C.; Lee, C.; Cheng, C.; Liao, C.; Wen, S.

    2001-12-01

    Tainan City has been known as an earthquake prone town since the early immigration of the ¡§Han¡" people from Mainland China about four hundred years ago. For the purpose of clarifying tectonic activity and paleo-earthquakes in the Tainan City area, we have finished the excavation of three trenches and the drilling of four holes at the so-called Houchiali Fault on the eastern margin of the Tainan tableland. We carefully observed the cores and exposures in the trenches, performed a detailed mapping, and took samples for C-14 dating and other types of analysis. The results show the trench sites are located at a flexure scarp without direct evidence of faulting. But, from the fact of tilting of Holocene sediments to about 50 degrees and the development of a fracture system in the sediments, one may realize that this is without doubt an active structure. We have tested many different models to interpret the observed geologic evidence in the trenches and outcrops, finally determined a growing fault-propagation fold model to be the best interpretation for the Tainan Anticline, while the Houchiali fault is a back-kink or a blind back-thrust type. A diapiric fold had been discussed as possible for a long time by many researchers, but a fault-propagation fold in origin does not contradict with a mud diapiric feature, which was formed during the folding. Field evidence shows that the main active phase of the Houchiali Fault and the Tainan Anticline would have been after the deposition of the Tainan Formation about two to three thousand years ago. During the active deformation phase, the Tawan Formation onlaped the Tainan Formation, as well as tilted during the folding, thus, beds on higher stratigraphic horizon show lower dip-angle. Estimated from a detailed geologic profile, the horizontal shortening of the anticline is estimated to be 30 meters. The vertical uplift of the Tainan Formation is also about 30 meters. This indicates that the deformation rate has been about 1

  8. Subacute combined degeneration of the spinal cord: MRI detection of preferential involvement of the posterior columns in a child

    International Nuclear Information System (INIS)

    Wolansky, L.J.; Goldstein, G.; Gozo, A.; Lee, H.J.; Sills, I.; Chatkupt, S.

    1995-01-01

    Subacute combined degeneration of the spinal cord (vitamin B 12 -deficient myelopathy) is a neurologic disorder manifesting progressive symptoms of paresthesia and spastic paralysis. As shown by pathology, it initially involves the posterior columns of the thoracic cord. We present a case of vitamin B 12 deficiency with preferential posterior column involvement of the thoracic cord in a child. Theoretically, this should be the earliest, most reversible stage of the disease, making recognition of this MRI pattern of critical importance. (orig.)

  9. Preferential treatment in transition economy the case of state-owned enterprises in the textile and garment industry in Vietnam

    OpenAIRE

    Knutsen, Hege Merete; Nguyen, Cuong Manh

    2004-01-01

    The article examines the role and contribution of preferential treatment of state enterprises to growth in the textile and garment industry. State enterprises are still the largest single sector in the textile and garment industry in Vietnam, but are losing market shares to private Vietnamese enterprises and foreign-owned enterprises despite the benefits that they enjoy. However, in the present context of economic transition and keen competition in the global market, well-managed state enterp...

  10. Embryonic common snapping turtles (Chelydra serpentina) preferentially regulate intracellular tissue pH during acid-base challenges.

    Science.gov (United States)

    Shartau, Ryan B; Crossley, Dane A; Kohl, Zachary F; Brauner, Colin J

    2016-07-01

    The nests of embryonic turtles naturally experience elevated CO2 (hypercarbia), which leads to increased blood PCO2  and a respiratory acidosis, resulting in reduced blood pH [extracellular pH (pHe)]. Some fishes preferentially regulate tissue pH [intracellular pH (pHi)] against changes in pHe; this has been proposed to be associated with exceptional CO2 tolerance and has never been identified in amniotes. As embryonic turtles may be CO2 tolerant based on nesting strategy, we hypothesized that they preferentially regulate pHi, conferring tolerance to severe acute acid-base challenges. This hypothesis was tested by investigating pH regulation in common snapping turtles (Chelydra serpentina) reared in normoxia then exposed to hypercarbia (13 kPa PCO2 ) for 1 h at three developmental ages: 70% and 90% of incubation, and yearlings. Hypercarbia reduced pHe but not pHi, at all developmental ages. At 70% of incubation, pHe was depressed by 0.324 pH units while pHi of brain, white muscle and lung increased; heart, liver and kidney pHi remained unchanged. At 90% of incubation, pHe was depressed by 0.352 pH units but heart pHi increased with no change in pHi of other tissues. Yearlings exhibited a pHe reduction of 0.235 pH units but had no changes in pHi of any tissues. The results indicate common snapping turtles preferentially regulate pHi during development, but the degree of response is reduced throughout development. This is the first time preferential pHi regulation has been identified in an amniote. These findings may provide insight into the evolution of acid-base homeostasis during development of amniotes, and vertebrates in general. © 2016. Published by The Company of Biologists Ltd.

  11. In defence of partisan justice - an ethical reflection on �the preferential option for the poor�

    Directory of Open Access Journals (Sweden)

    PJ Naude

    2007-09-01

    Full Text Available Can one defend a form of partisan justice? This question is answered in the affirmative in the light of two broad arguments:� The theological argument arises from the preferential option for the poor from Latin America, and the philosophical argument is derived from John Rawls�� notion of the least� advantaged representative person and assistance due to burdened societies in a global context. In closing, a number of important implications of such a partisan notion of both distributive and cultural justice are explicated. This article is developed in three sections. The first section briefly sketches a profile of the different theological arguments underlying a preferential option for the poor as particularly developed by Latin American liberation theologians, and later accepted in wider ecumenical circles.� In the second section, philosophical arguments for a position of �prioritarianism� which seems to support such �preferential option� are outlined.� This is attempted via a discussion of two influential books by well-known� American political philosopher , John Rawls, namely his A theory of justice (1973, and The law of peoples (1999.� Section three concludes the article by demonstrating the synergy between these theological and philosophical views, and by pointing out � in a provisional manner - the important consequences of such a �preferential� or �partisan� view for guiding ethical reflection on local and global socio-economic relations.

  12. Preferential growth of short aligned, metallic-rich single-walled carbon nanotubes from perpendicular layered double hydroxide film.

    Science.gov (United States)

    Zhao, Meng-Qiang; Tian, Gui-Li; Zhang, Qiang; Huang, Jia-Qi; Nie, Jing-Qi; Wei, Fei

    2012-04-07

    Direct bulk growth of single-walled carbon nanotubes (SWCNTs) with required properties, such as diameter, length, and chirality, is the first step to realize their advanced applications in electrical and optical devices, transparent conductive films, and high-performance field-effect transistors. Preferential growth of short aligned, metallic-rich SWCNTs is a great challenge to the carbon nanotube community. We report the bulk preferential growth of short aligned SWCNTs from perpendicular Mo-containing FeMgAl layered double hydroxide (LDH) film by a facile thermal chemical vapor deposition with CH(4) as carbon source. The growth of the short aligned SWCNTs showed a decreased growth velocity with an initial value of 1.9 nm s(-1). Such a low growth velocity made it possible to get aligned SWCNTs shorter than 1 μm with a growth duration less than 15 min. Raman spectra with different excitation wavelengths indicated that the as-grown short aligned SWCNTs showed high selectivity of metallic SWCNTs. Various kinds of materials, such as mica, quartz, Cu foil, and carbon fiber, can serve as the substrates for the growth of perpendicular FeMoMgAl LDH films and also the growth of the short aligned SWCNTs subsequently. These findings highlight the easy route for bulk preferential growth of aligned metallic-rich SWCNTs with well defined length for further bulk characterization and applications. This journal is © The Royal Society of Chemistry 2012

  13. Src Kinase becomes preferentially associated with the VEGFR, KDR/Flk-1, following VEGF stimulation of vascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Wang Jing

    2002-12-01

    Full Text Available Abstract Background The cytoplasmic tyrosine kinase, Src, has been found to play a crucial role in VEGF (vascular endothelial growth factor – dependent vascular permeability involved in angiogenesis. The two main VEGFRs present on vascular endothelial cells are KDR/Flk-1 (kinase insert domain-containing receptor/fetal liver kinase-1 and Flt-1 (Fms-like tyrosine kinase-1. However, to date, it has not been determined which VEGF receptor (VEGFR is involved in binding to and activating Src kinase following VEGF stimulation of the receptors. Results In this report, we demonstrate that Src preferentially associates with KDR/Flk-1 rather than Flt-1 in human umbilical vein endothelial cells (HUVECs, and that VEGF stimulation resulted in an increase of Src activity associated with activated KDR/Flk-1. These findings were determined through immunoprecipitation-kinase experiments and coimmunoprecipitation studies, and were further confirmed by GST-pull-down assays and Far Western studies. However, Fyn and Yes, unlike Src, were found to associate preferentially with Flt-1. Conclusions Thus, Src preferentially associates with KDR/Flk-1, rather than with Flt-1, upon VEGF stimulation in endothelial cells. Our findings further highlight the potential significance of upregulated KDR/Flk-1-associated Src activity in the process of angiogenesis, and help to elucidate more clearly the specific roles and mechanisms involving Src family tyrosine kinase in VEGF-stimulated signal transduction events.

  14. A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide

    Directory of Open Access Journals (Sweden)

    D. M. Krzeminska

    2013-03-01

    Full Text Available The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g., layering, preferential flow paths such as fissures of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps.

  15. Preferential uptake of ribose by primitive cells might explain why RNA was favored over its analogs

    Science.gov (United States)

    Pohorille, Andrew; Wei, Chenyu

    Permeation of molecules through membranes is a fundamental process in biological systems, which not only involves mass and signal transfers between the interior of a contemporary cell and its environment, but was also of crucial importance in the origin of life. In the absence of complex protein transporters, nutrients and building blocks of biopolymers must have been able to permeate membranes at sufficient rates to support primordial metabolism and cel-lular reproduction. From this perspective one class of solutes that is of special interest are monosaccharides, which serve not only as nutritional molecules but also as building blocks for information molecules. In particular, ribose is a part of the RNA backbone, but RNA analogs containing a number of other sugars have also been shown to form stable duplexes. Why, among these possibilities, ribose (and, subsequently, deoxyribose) was selected for the backbone of information polymers is still poorly understood. It was recently found that ribose permeates membranes an order of magnitude faster than its diastereomers, arabinose and xylose [1]. On this basis it was hypothesized that differences in membrane permeability to aldopentoses provide a mechanism for preferential delivery of ribose to primitive cells for subsequent, selective incorporation into nucleotides and their polymers. However, the origins of these unusually large differences had not been well understood. We addressed this issue in molecular dynamics simulations combined with free energy calculations. It was found that the free energy barrier for transferring ribose from water to the bilayer is lower by 1.5-2 kcal/mol than the barrier for transferring the other two aldopentoses. The calculated [2] and measured [1] permeability coefficients are in an excellent agreement. The sugar structures that permeate the membrane are -pyranoses, with a possible contribution of the -anomer for arabinose. The furanoid form of ribose is not substantially involved in

  16. Preferential flow and mixing process in the chemical recharge in subsurface catchments: observations and modeling

    Science.gov (United States)

    Gascuel-Odoux, C.; Rouxel, M.; Molenat, J.; Ruiz, L.; Aquilina, L.; Faucheux, M.; Labasque, T.; Sebilo, M.

    2012-04-01

    Shallow groundwater that develops on hillslopes is the main compartment in headwater catchments for flow and solute transport to rivers. Although spatial and temporal variations in its chemical composition are reported in the literature, there is no coherent description of the way these variations are organized, nor is there an accepted conceptual model for the recharge mechanisms and flows in the groundwater involved. We instrumented an intensive farming and subsurface dominant catchment located in Oceanic Western Europe (Kerbernez, Brittany, France), a headwater catchment included in the Observatory for Research on Environment AgrHyS (Agro-Hydro-System) and a part of the French Network of catchments for environmental research (SOERE RBV focused on the Critical Zone). These systems are strongly constrained by anthropogenic pressures (agriculture) and are characterized by a clear non-equilibrium status. A network of 42 nested piezometers was installed along a 200 m hillslope allowing water sampling along two transects in the permanent water table as well as in what we call the "fluctuating zone", characterized by seasonal alternance of saturated and unsaturated conditions. Water composition was monitored at high frequency (weekly) over a 3-year period for major anion composition and over a one year period for detailed 15N, CFC, SF6 and other dissolved gases. The results demonstrated that (i) the anionic composition in water table fluctuation zone varied significantly compared to deeper portions of the aquifer on the hillslope, confirming that this layer constitutes a main compartment for the mixing of new recharge water and old groundwater, (ii) seasonally, the variations of 15N and CFC are much higher during the recharge period than during the recession period, confirming the preferential flow during early recharge events, iii) variations of nitrate 15N and O18 composition was suggesting any significant denitrification process in the fluctuating zone, confirming

  17. Epidemic outbreaks in growing scale-free networks with local structure

    Science.gov (United States)

    Ni, Shunjiang; Weng, Wenguo; Shen, Shifei; Fan, Weicheng

    2008-09-01

    The class of generative models has already attracted considerable interest from researchers in recent years and much expanded the original ideas described in BA model. Most of these models assume that only one node per time step joins the network. In this paper, we grow the network by adding n interconnected nodes as a local structure into the network at each time step with each new node emanating m new edges linking the node to the preexisting network by preferential attachment. This successfully generates key features observed in social networks. These include power-law degree distribution pk∼k, where μ=(n-1)/m is a tuning parameter defined as the modularity strength of the network, nontrivial clustering, assortative mixing, and modular structure. Moreover, all these features are dependent in a similar way on the parameter μ. We then study the susceptible-infected epidemics on this network with identical infectivity, and find that the initial epidemic behavior is governed by both of the infection scheme and the network structure, especially the modularity strength. The modularity of the network makes the spreading velocity much lower than that of the BA model. On the other hand, increasing the modularity strength will accelerate the propagation velocity.

  18. GrOW briefs: From research to policy | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2017-10-17

    Oct 17, 2017 ... ​For access to more GrOW findings and literature, visit the GrOW Research Series. Learn more about the GrOW program. What we do · Funding · Resources · About IDRC. Knowledge. Innovation. Solutions. Careers · Contact Us · Site map. Sign up now for IDRC news and views sent directly to your inbox ...

  19. Fostering and sustaining innovation in a Fast Growing Agile Company

    OpenAIRE

    Moe, NilsBrede; Barney, Sebastian; Aurum, Aybüe; Khurum, Mahvish; Wohlin, Claes; Barney, Hamish; Gorschek, Tony; Winata, Martha

    2012-01-01

    Sustaining innovation in a fast growing software development company is difficult. As organisations grow, peoples' focus often changes from the big picture of the product being developed to the specific role they fill. This paper presents two complementary approaches that were successfully used to support continued developer-driven innovation in a rapidly growing Australian agile software development company. The method "FedEx TM Day" gives developers one day to showcase a proof of concept th...

  20. Cell wall integrity signaling in plants: "To grow or not to grow that's the question".

    Science.gov (United States)

    Voxeur, Aline; Höfte, Herman

    2016-09-01

    Plants, like yeast, have the ability to monitor alterations in the cell wall architecture that occur during normal growth or in changing environments and to trigger compensatory changes in the cell wall. We discuss how recent advances in our understanding of the cell wall architecture provide new insights into the role of cell wall integrity sensing in growth control. Next we review the properties of membrane receptor-like kinases that have roles in pH control, mechano-sensing and reactive oxygen species accumulation in growing cells and which may be the plant equivalents of the yeast cell wall integrity (CWI) sensors. Finally, we discuss recent findings showing an increasing role for CWI signaling in plant immunity and the adaptation to changes in the ionic environment of plant cells. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Incorporating Edge Information into Best Merge Region-Growing Segmentation

    Science.gov (United States)

    Tilton, James C.; Pasolli, Edoardo

    2014-01-01

    We have previously developed a best merge region-growing approach that integrates nonadjacent region object aggregation with the neighboring region merge process usually employed in region growing segmentation approaches. This approach has been named HSeg, because it provides a hierarchical set of image segmentation results. Up to this point, HSeg considered only global region feature information in the region growing decision process. We present here three new versions of HSeg that include local edge information into the region growing decision process at different levels of rigor. We then compare the effectiveness and processing times of these new versions HSeg with each other and with the original version of HSeg.

  2. Inhibition of Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa PAO1 by Ayurveda Spice Clove (Syzygium Aromaticum Bud Extract

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2012-03-01

    Full Text Available Quorum sensing controls the virulence determinants in most proteobacteria. In this work, the hexane, chloroform and methanol extracts of an Ayurveda spice, namely clove (Syzygium aromaticum, shown anti-quorum sensing activity. Hexane and methanol extracts of clove inhibited the response of C. violaceum CV026 to exogenously supplied N‑hexanoylhomoserine lactone, in turn preventing violacein production. Chloroform and methanol extracts of clove significantly reduced bioluminescence production by E. coli [pSB1075] grown in the presence of N-(3-oxododecanoyl-L-homoserine lactone. We demonstrated that clove extract inhibited quorum sensing-regulated phenotypes in Pseudomonas aeruginosa PA01, including expression of lecA::lux (by hexane extract, swarming (maximum inhibition by methanol extract, pyocyanin (maximum inhibition by hexane extract. This study shows that the presence of natural compounds that exhibit anti-quorum sensing activity in the clove extracts may be useful as the lead of anti-infective drugs.

  3. Cloning, purification, crystallization and preliminary X-ray studies of flagellar hook scaffolding protein FlgD from Pseudomonas aeruginosa PAO1

    International Nuclear Information System (INIS)

    Luo, Miao; Niu, Siqiang; Yin, Yibing; Huang, Ailong; Wang, Deqiang

    2009-01-01

    In order to better elucidate the functions of FlgD in flagellar hook biosynthesis, the three-dimensional structure of FlgD is being determined by X-ray crystallography. Here, the expression, purification, crystallization and preliminary crystallographic analysis of FlgD from P. aeruginosa are reported. FlgD regulates the assembly of the hook cap structure to prevent leakage of hook monomers into the medium and hook monomer polymerization and also plays a role in determination of the correct hook length, with the help of the FliK protein. In order to better elucidate the functions of FlgD in flagellar hook biosynthesis, the three-dimensional structure of FlgD is being determined by X-ray crystallography. Here, the expression, purification, crystallization and preliminary crystallographic analysis of FlgD from P. aeruginosa are reported. The crystal belonged to space group I222 and diffracted to a resolution of 2.5 Å, with unit-cell parameters a = 116.47, b = 118.71, c = 118.85 Å. The crystals are most likely to contain three molecules in the asymmetric unit, with a V M value of 2.73 Å 3 Da −1

  4. Transcriptional and proteomic response of Pseudomonas aeruginosa PAO1 to spaceflight conditions involves Hfq regulation and reveals a role for oxygen

    Data.gov (United States)

    National Aeronautics and Space Administration — Characterization of bacterial behavior in the microgravity environment of spaceflight is of importance towards risk assessment and prevention of infectious disease...

  5. Melting lizards and crying mailboxes: Children's preferential recall of minimally counterintuitive concepts

    Science.gov (United States)

    Banerjee, Konika; Haque, Omar S.; Spelke, Elizabeth S.

    2013-01-01

    Previous research with adults suggests that a catalog of minimally counterintuitive concepts, which underlies supernatural or religious concepts, may constitute a cognitive optimum, and is therefore cognitively encoded and culturally transmitted more successfully than either entirely intuitive concepts or maximally counterintuitive concepts. The current study examines whether children's concept recall similarly is sensitive to the degree of conceptual counterintuitiveness (operationalized as a concept's number of ontological domain violations) for items presented in the context of a fictional narrative. Seven-to-nine-year old children who listened to a story including both intuitive and counterintuitive concepts recalled the counterintuitive concepts containing one (Experiment 1) or two (Experiment 2) but not three (Experiment 3) violations of intuitive ontological expectations significantly more and in greater detail than the intuitive concepts, both immediately after hearing the story and one week later. We conclude that one or two violations of expectation may be a cognitive optimum for children: they are more inferentially rich and therefore more memorable, whereas three or more violations diminish memorability for target concepts. These results suggest that the cognitive bias for minimally counterintuitive ideas is present and active early in human development, near the start of formal religious instruction. This finding supports a growing literature suggesting that diverse, early- emerging, evolved psychological biases predispose humans to hold and perform religious beliefs and practices whose primary form and content is not derived from arbitrary custom or the social environment alone. PMID:23631765

  6. Preferential methanogenic biodegradation of short-chain n-alkanes by microbial communities from two different oil sands tailings ponds.

    Science.gov (United States)

    Mohamad Shahimin, Mohd Faidz; Foght, Julia M; Siddique, Tariq

    2016-05-15

    Oil sands tailings ponds harbor diverse anaerobic microbial communities capable of methanogenic biodegradation of solvent hydrocarbons entrained in the tailings. Mature fine tailings (MFT) from two operators (Albian and CNRL) that use different extraction solvents were incubated with mixtures of either two (n-pentane and n-hexane) or four (n-pentane, n-hexane, n-octane and n-decane) n-alkanes under methanogenic conditions for ~600 d. Microbes in Albian MFT began methane production by ~80 d, achieving complete depletion of n-pentane and n-hexane in the two-alkane mixture and their preferential biodegradation in the four-alkane mixture. Microbes in CNRL MFT preferentially metabolized n-octane and n-decane in the four-alkane mixture after a ~80 d lag but exhibited a lag of ~360 d before commencing biodegradation of n-pentane and n-hexane in the two-alkane mixture. 16S rRNA gene pyrosequencing revealed Peptococcaceae members as key bacterial n-alkane degraders in all treatments except CNRL MFT amended with the four-alkane mixture, in which Anaerolineaceae, Desulfobacteraceae (Desulfobacterium) and Syntrophaceae (Smithella) dominated during n-octane and n-decane biodegradation. Anaerolineaceae sequences increased only in cultures amended with the four-alkane mixture and only during n-octane and n-decane biodegradation. The dominant methanogens were acetoclastic Methanosaetaceae. These results highlight preferential n-alkane biodegradation by microbes in oil sands tailings from different producers, with implications for tailings management and reclamation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Preferential processing of task-irrelevant beloved-related information and task performance: Two event-related potential studies.

    Science.gov (United States)

    Langeslag, Sandra J E; van Strien, Jan W

    2017-09-18

    People who are in love have better attention for beloved-related information, but report having trouble focusing on other tasks, such as (home)work. So, romantic love can both improve and hurt cognition. Emotional information is preferentially processed, which improves task performance when the information is task-relevant, but hurts task performance when it is task-irrelevant. Because beloved-related information is highly emotional, the effects of romantic love on cognition may resemble these effects of emotion on cognition. We examined whether beloved-related information is preferentially processed even when it is task-irrelevant and whether this hurts task performance. In two event-related potential studies, participants who had recently fallen in love performed a visuospatial short-term memory task. Task-irrelevant beloved, friend, and stranger faces were presented during maintenance (Study 1), or encoding (Study 2). The Early Posterior Negativity (EPN) reflecting early automatic attentional capturing and the Late Positive Potential (LPP) reflecting sustained motivated attention were largest for beloved pictures. Thus, beloved pictures are preferentially processed even when they are task-irrelevant. Task performance and reaction times did not differ between beloved, friend, and stranger conditions. Nevertheless, self-reported obsessive thinking about the beloved tended to correlate negatively with task performance, and positively with reaction times, across conditions. So, although task-irrelevant beloved-related information does not impact task performance, more obsessive thinking about the beloved might relate to poorer and slower overall task performance. More research is needed to clarify why people experience trouble focusing on beloved-unrelated tasks and how this negative effect of love on cognition could be reduced. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Interstitial ultrasound ablation of tumors within or adjacent to bone: Contributions of preferential heating at the bone surface

    Science.gov (United States)

    Scott, Serena J.; Prakash, Punit; Salgaonkar, Vasant; Jones, Peter D.; Cam, Richard N.; Han, Misung; Rieke, Viola; Burdette, E. Clif; Diederich, Chris J.

    2013-02-01

    Preferential heating of bone due to high ultrasound attenuation may enhance thermal ablation performed with cathetercooled interstitial ultrasound applicators in or near bone. At the same time, thermally and acoustically insulating cortical bone may protect sensitive structures nearby. 3D acoustic and biothermal transient finite element models were developed to simulate temperature and thermal dose distributions during catheter-cooled interstitial ultrasound ablation near bone. Experiments in ex vivo tissues and tissue-mimicking phantoms were performed to validate the models and to quantify the temperature profiles and ablated volumes for various distances between the interstitial applicator and the bone surface. 3D patient-specific models selected to bracket the range of clinical usage were developed to investigate what types of tumors could be treated, applicator configurations, insertion paths, safety margins, and other parameters. Experiments show that preferential heating at the bone surface decreases treatment times compared to when bone is absent and that all tissue between an applicator and bone can be ablated when they are up to 2 cm apart. Simulations indicate that a 5-7 mm safety margin of normal bone is needed to protect (thermal dose tumors 1.0-3.8 cm (L) and 1.3-3.0 cm (D) near or within bone were ablated (thermal dose > 240 CEM43°C) within 10 min without damaging the nearby spinal cord, lungs, esophagus, trachea, or major vasculature. Preferential absorption of ultrasound by bone may provide improved localization, faster treatment times, and larger treatment zones in tumors in and near bone compared to other heating modalities.

  9. Solubility and preferential solvation of some n-alkyl-parabens in methanol + water mixtures at 298.15 K

    International Nuclear Information System (INIS)

    Cárdenas, Zaira J.; Jiménez, Daniel M.; Delgado, Daniel R.; Almanza, Ovidio A.; Jouyban, Abolghasem; Martínez, Fleming; Acree, William E.

    2017-01-01

    Highlights: • Parabens equilibrium solubility was determined in methanol + water binary mixtures at 298.15 K. • Solubility values were correlated with the Jouyban-Acree model. • Preferential solvation parameters were derived by using the IKBI method. • δx 1,3 values are negative in water-rich mixtures but positive in the other mixtures. - Abstract: Methyl, ethyl and propyl parabens equilibrium solubility was determined in (methanol + water) binary mixtures at 298.15 K. The mole fraction solubility of these compounds increased in 503 (from 2.40 × 10 −4 to 0.121), 1377 (from 9.86 × 10 −5 to 0.136) and 4597 (from 3.73 × 10 −5 to 0.171) times when passing from neat water to neat methanol, for methyl, ethyl and propyl parabens, respectively. All these solubility values were correlated with the Jouyban-Acree model. Preferential solvation parameters by methanol (δx 1,3 ) of these parabens were derived from their thermodynamic solution properties using the inverse Kirkwood-Buff integrals (IKBI) method. For all compounds δx 1,3 values are negative in water-rich mixtures but positive in mixtures with methanol mole fraction greater than 0.32. It is conjecturable that in the former case the hydrophobic hydration around non-polar groups of parabens plays a relevant role in the solvation. Besides, the preferential solvation of these solutes by methanol in mixtures of similar co-solvent compositions and in methanol-rich mixtures could be explained in terms of the higher basic behaviour of methanol.

  10. Temperature Sensitivity of Soil Respiration to Nitrogen Fertilization: Varying Effects between Growing and Non-Growing Seasons

    Science.gov (United States)

    Liu, Qingfang; Wang, Rui; Li, Rujian; Hu, Yaxian; Guo, Shengli

    2016-01-01

    Nitrogen (N) fertilization has a considerable effect on food production and carbon cycling in agro-ecosystems. However, the impacts of N fertilization rates on the temperature sensitivity of soil respiration (Q10) were controversial. Five N rates (N0, N45, N90, N135, and N180) were applied to a continuous winter wheat (Triticum aestivum L.) crop on the semi-arid Loess Plateau, and the in situ soil respiration was monitored during five consecutive years from 2008 to 2013. During the growing season, the mean soil respiration rates increased with increasing N fertilization rates, peaking at 1.53 μmol m−2s−1 in the N135 treatment. A similar dynamic pattern was observed during the non-growing season, yet on average with 7.3% greater soil respiration rates than the growing season. In general for all the N fertilization treatments, the mean Q10 value during the non-growing season was significantly greater than that during the growing season. As N fertilization rates increased, the Q10 values did not change significantly in the growing season but significantly decreased in the non-growing season. Overall, N fertilization markedly influenced soil respirations and Q10 values, in particular posing distinct effects on the Q10 values between the growing and non-growing seasons. PMID:27992576

  11. Evidence of preferential diffusion and segregation of impurities at grain boundaries in very pure niobium used for radiofrequency cavities

    International Nuclear Information System (INIS)

    Antoine, C.; Bonin, B.; Safa, H.; Chevarier, A.; Chevarier, N.; Roux, B.

    1996-01-01

    Grain boundaries (GB) of titaniferous, heat treated and then etched niobium have been observed by nuclear microprobe analysis. The very small area of the probe allows to measure by PIXE quantities of titanium as low as one monolayer at the GB. Concentrations of titanium as high as some atomic percent were found on 6 μm etched samples, giving indication of a preferential diffusion and/or segregation at GB. Titanium was detectable also on 15 μm etched samples but was bellow the sensitivity of the microprobe for 35 μm etched samples. (author)

  12. Evidence of preferential diffusion and segregation of impurities at grain boundaries in very pure niobium used for radiofrequency cavities

    International Nuclear Information System (INIS)

    Antoine, C.; Bonin, B.; Safa, H.; Berthier, B.; Tessier, E.; Trocelier, P.; Chevarier, A.; Chevarier, N.; Roux, B.

    1996-04-01

    In order to overcome dissipation due to impurity segregation at grain boundary, niobium cavities are submitted to a purification annealing (1300 deg C ± 200 deg C under vacuum) during which titanium is evaporated onto the Nb surface. The resulting titanium layer acts as a solid state getter reacting with light impurities (H, C, N, O), thereby removing these impurities from the bulk of the niobium. Evidence of preferential titanium diffusion and segregation at grain boundaries has been studied using PIXE analysis induced by proton microbeam. (author)

  13. Preferential Creation of Polar Translational Boundaries by Interface Engineering in Antiferroelectric PbZrO3 Thin Films

    OpenAIRE

    Wei XK; Vaideeswaran K; Sandu CS; Jia CL; Setter N

    2015-01-01

    Polar translational boundaries (PTBs) are preferentially created in antiferroelectric PbZrO3 films through interfacial engineering. Probe corrected scanning transmission electron microscopy studies reveal that RIII 1 and RI 1 type PTBs are favorably created in PbZrO3/BaZrO3/SrTiO3 and PbZrO3/SrTiO3 films respectively. The relationship between interfacial strain and the internal strain of boundaries is the driving force for the selective formation of PTBs.

  14. Effects of CT Number-Derived Matrix Density on Preferential Flow 1 and Transport in a Macroporous Agricultural Soil

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Moldrup, Per; Lamandé, Mathieu

    2015-01-01

    risks to public health. This study was focused on establishing links between the structural pore space and preferential transport using a combination of standard physical measurement methods for air and water permeabilities, breakthrough experiments, and X-ray Computed Tomography (CT) on large soil...... columns. Substantial structural heterogeneity that resulted in significant variations of flow and tracer transport was observed, despite the textural similarity of investigated samples. Quantification of macropore characteristics with X-ray CT was useful but not sufficient to explain the variability...

  15. Subacute combined degeneration of the spinal cord: MRI detection of preferential involvement of the posterior columns in a child

    Energy Technology Data Exchange (ETDEWEB)

    Wolansky, L.J. [Dept. of Radiology, UMDNJ-New Jersey Medical School, Newark, NJ (United States); Goldstein, G. [Dept. of Radiology, UMDNJ-New Jersey Medical School, Newark, NJ (United States); Gozo, A. [Dept. of Neurosciences, UMDNJ-New Jersey Medical School, Newark, NJ (United States)]|[Dept. of Pediatrics, UMDNJ-New Jersey Medical School, Newark, NJ (United States)]|[Children`s Hospital of New Jersey, Newark, NJ (United States); Lee, H.J. [Dept. of Radiology, UMDNJ-New Jersey Medical School, Newark, NJ (United States); Sills, I. [Dept. of Pediatrics, UMDNJ-New Jersey Medical School, Newark, NJ (United States)]|[Children`s Hospital of New Jersey, Newark, NJ (United States); Chatkupt, S. [Dept. of Neurosciences, UMDNJ-New Jersey Medical School, Newark, NJ (United States)]|[Dept. of Pediatrics, UMDNJ-New Jersey Medical School, Newark, NJ (United States)]|[Children`s Hospital of New Jersey, Newark, NJ (United States)

    1995-03-01

    Subacute combined degeneration of the spinal cord (vitamin B{sub 12}-deficient myelopathy) is a neurologic disorder manifesting progressive symptoms of paresthesia and spastic paralysis. As shown by pathology, it initially involves the posterior columns of the thoracic cord. We present a case of vitamin B{sub 12} deficiency with preferential posterior column involvement of the thoracic cord in a child. Theoretically, this should be the earliest, most reversible stage of the disease, making recognition of this MRI pattern of critical importance. (orig.)

  16. Performance Of Growing Pigs And Finisher Broilers Housed Together

    African Journals Online (AJOL)

    Growth performance and cost of feeding young growing pigs and finisher broilers under integrated broiler/pig production system were investigated. Four young growing pigs (the control) were housed in pen A and fed 4% of their body weight as commercial growers feed. Another 4 were housed in pen B with broilers in ...

  17. Evolution of Communicative Competence in Adolescents Growing up in Orphanages

    Science.gov (United States)

    Ribakova, Laysan A.; Parfilova, Gulfia G.; Karimova, Lilya Sh.; Karimova, Raushan B.

    2015-01-01

    The article describes features of the communicative competence evolution in adolescents growing up in orphanages. The specificity is revealed and definition is given to key concept of the research, namely "communicative competence". Authors emphasize and demonstrate the evaluation peculiarities of the adolescents, growing up in…

  18. Growth and Economic Opportunities for Women (GrOW) Frequently ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Alejandra

    GrOW will take a broad perspective on the types of questions and evidence on ... question; (2) set the outcome in the broader context of the underlying programme theory, ... Communications from the GrOW team with applicants during the ... There are specific criteria and application processes for this call that should be.

  19. Temperature fields in a growing solar silicon crystal

    Directory of Open Access Journals (Sweden)

    Kondrik A. I.

    2012-06-01

    Full Text Available The optimal thermal terms for growing by Czochralski method Si single-crystals, suitable for making photoelectric energy converters, has been defined by the computer simulation method. Dependences of temperature fields character and crystallization front form on the diameter of the crystal, stage and speed of growing, and also on correlation between diameter and height of the crystal has been studied.

  20. Growing media alternatives for forest and native plant nurseries

    Science.gov (United States)

    Thomas D. Landis; Nancy Morgan

    2009-01-01

    The choice of growing medium, along with container type, is one of the critical decisions that must be made when starting a nursery. The first growing medium was called "compost" and was developed in the 1930s at the John Innes Horticultural Institute in Great Britain. It consisted of a loam soil that was amended with peat moss, sand, and fertilizers (Bunt...

  1. The effect of lumbosacral manipulation on growing pains

    Directory of Open Access Journals (Sweden)

    Dawid de Beer

    2015-06-01

    Conclusion: The results from this study, specifically the feedback from parent(s/guardians(s and the pain diaries, indicated that spinal manipulation is beneficial in the treatment of growing pains. The results also showed that other methods of treating growing pains, such as simple leg rubs, may also bring relief.

  2. Hydroxychloroquine preferentially induces apoptosis of CD45RO+ effector T cells by inhibiting autophagy: A possible mechanism for therapeutic modulation of T cells

    OpenAIRE

    van Loosdregt, Jorg; Spreafico, Roberto; Rossetti, Maura; Prakken, Berent J; Lotz, Martin; Albani, Salvatore

    2013-01-01

    Although hydroxychloroquine is used for treatment of numerous autoimmune disorders the mechanism is unclear. We here demonstrate that hydroxychloroquine preferentially induces apoptosis of CD45RO+ memory and effector T cells by inhibiting the survival pathway of autophagy.

  3. Assessment of drought during corn growing season in Northeast China

    Science.gov (United States)

    Zhang, Qi; Hu, Zhenghua

    2018-04-01

    Northeast China has experienced extensive climate change during the past decades. Corn is the primary production crop in China and is sensitive to meteorological disasters, especially drought. Drought has thus greatly endangered crop production and the country's food security. The majority of previous studies has not highlighted farming adaptation activities undertaken within the changed climate, which should not be neglected. In this study, we assessed drought hazard in the corn vegetation growing period, the reproductive growing period, and the whole growing period based on data for yearly corn phenology, daily precipitation, and temperature gathered at 26 agro-meteorological stations across Northeast China from 1981 to 2009. The M-K trend test was used to detect trends in sowing date and drought. The standardized precipitation evapotranspiration index (SPEI) was used to describe drought. Drought frequency and intensity were used to assess the drought hazard in the region. We found that the sowing date was delayed in the southern part of the study area, coupled with a trend towards a shorter and more humid vegetation growing period. In the northern part of the study area, an earlier sowing date increased the length of the vegetation growing period and the reproductive growing period, while drying trends occurred within the two corn growing periods. We assessed the drought hazard during each growing period: the reproductive growing period faced a more severe drought hazard and was also the period where corn was most sensitive to water stress. Drought hazard during the total growing period was closely related to corn yield.

  4. I publish in I edit?--Do editorial board members of urologic journals preferentially publish their own scientific work?

    Science.gov (United States)

    Mani, Jens; Makarević, Jasmina; Juengel, Eva; Ackermann, Hanns; Nelson, Karen; Bartsch, Georg; Haferkamp, Axel; Blaheta, Roman A

    2013-01-01

    Scientists who are members of an editorial board have been accused of preferentially publishing their scientific work in the journal where they serve as editor. Reputation and academic standing do depend on an uninterrupted flow of published scientific work and the question does arise as to whether publication mainly occurs in the self-edited journal. This investigation was designed to determine whether editorial board members of five urological journals were more likely to publish their research reports in their own rather than in other journals. A retrospective analysis was conducted for all original reports published from 2001-2010 by 65 editorial board members nominated to the boards of five impact leading urologic journals in 2006. Publications before editorial board membership, 2001-2005, and publications within the period of time as an editorial board member, 2006-2010, were identified. The impact factors of the journals were also recorded over the time period 2001-2010 to see whether a change in impact factor correlated with publication locality. In the five journals as a whole, scientific work was not preferentially published in the journal in which the scientists served as editor. However, significant heterogeneity among the journals was evident. One journal showed a significant increase in the amount of published papers in the 'own' journal after assumption of editorship, three journals showed no change and one journal showed a highly significant decrease in publishing in the 'own' journal after assumption of editorship.

  5. A Particular Appetite: Cosmological Hydrodynamic Simulations of Preferential Accretion in the Supermassive Black Holes of Milky Way Size Galaxies

    Science.gov (United States)

    Sanchez, Natalie; Bellovary, Jillian M.; Holley-Bockelmann, Kelly

    2016-01-01

    With the use of cosmological hydrodynamic simulations of Milky Way-type galaxies, we identify the preferential source of gas that is accreted by the supermassive black holes (SMBHs) they host. We examine simulations of two Milky Way analogs, each distinguished by a differing merger history. One galaxy is characterized by several major mergers and the other has a more quiescent history. By examining and comparing these two galaxies, which have a similar structure at z=0, we asses the importance of merger history on black hole accretion. This study is an extension of Bellovary et. al. 2013, which studied accretion onto SMBHs in massive, high redshift galaxies. Bellovary found that the fraction of gas accreted by the galaxy was proportional to that which was accreted by its SMBH. Contrary to Bellovary's previous results, we found that though the gas accreted by a quiescent galaxy will mirror the accretion of its central SMBH, a galaxy that is characterized by an active merger history will have a SMBH that preferentially accretes gas gained through mergers. We move forward by examining the angular momentum of the gas accreted by these Milky Way-type galaxies to better understand the mechanisms fueling their central SMBH.

  6. The application of in situ analytical transmission electron microscopy to the study of preferential intergranular oxidation in Alloy 600

    Energy Technology Data Exchange (ETDEWEB)

    Burke, M.G., E-mail: m.g.burke@manchester.ac.uk; Bertali, G.; Prestat, E.; Scenini, F.; Haigh, S.J.

    2017-05-15

    In situ analytical transmission electron microscopy (TEM) can provide a unique perspective on dynamic reactions in a variety of environments, including liquids and gases. In this study, in situ analytical TEM techniques have been applied to examine the localised oxidation reactions that occur in a Ni-Cr-Fe alloy, Alloy 600, using a gas environmental cell at elevated temperatures. The initial stages of preferential intergranular oxidation, shown to be an important precursor phenomenon for intergranular stress corrosion cracking in pressurized water reactors (PWRs), have been successfully identified using the in situ approach. Furthermore, the detailed observations correspond to the ex situ results obtained from bulk specimens tested in hydrogenated steam and in high temperature PWR primary water. The excellent agreement between the in situ and ex situ oxidation studies demonstrates that this approach can be used to investigate the initial stages of preferential intergranular oxidation relevant to nuclear power systems. - Highlights: • In situ analytical TEM has been performed in 1 bar H{sub 2}-H{sub 2}O vapor at 360–480 °C. • Nanoscale GB migration and solute partitioning correlate with ex situ data for Alloy 600 in H{sub 2}-steam. • This technique can provide new insights into localised reactions associated with localised oxidation.

  7. The effects of preferential flow and soil texture on risk assessments of a NORM waste disposal site

    International Nuclear Information System (INIS)

    Pontedeiro, E.M.; Genuchten, M.Th. van; Cotta, R.M.; Simunek, J.

    2010-01-01

    This paper investigates the environmental fate of radionuclide decay chains (specially the 238 U and 232 Th series) being released from a conventional mining installation processing ore containing natural occurring radioactive materials (NORMs). Contaminated waste at the site is being disposed off in an industrial landfill on top of a base of earth material to ensure integrity of the deposit over relatively long geologic times (thousands of years). Brazilian regulations, like those of many other countries, require a performance assessment of the disposal facility using a leaching and off-site transport scenario. We used for this purpose the HYDRUS-1D software package to predict long-term radionuclide transport vertically through both the landfill and the underlying unsaturated zone, and then laterally in groundwater. We assumed that a downgradient well intercepting groundwater was the only source of water for a resident farmer, and that all contaminated water from the well was somehow used in the biosphere. The risk assessment was carried out for both a best-case scenario assuming equilibrium transport in a fine-textured (clay) subsurface, and a worst-case scenario involving preferential flow through a more coarse-textured subsurface. Results show that preferential flow and soil texture both can have a major effect on the results, depending upon the specific radionuclide involved.

  8. Preferential adsorption of volatile hydrocarbons on high surface area chalcogels KMBiTe 3 (M = Cr, Zn, Fe)

    KAUST Repository

    Edhaim, Fatimah

    2017-12-21

    Three chalcogels KCrBiTe3, KZnBiTe3, and KFeBiTe3 were synthesized by the sol–gel metathesis route. K+ and the transition metal cations Cr2+, Zn2+ or Fe2+ connect [BiTe3]3− anions to form amorphous black compounds. Supercritical drying of the black gels produced porous materials with BET surface areas of 230 m2/g (KCrBiTe3), 450 m2/g (KZnBiTe3) and 514 m2/g (KFeBiTe3). The adsorption properties of the resulting chalcogenide aerogels or chalcogels have been studied using volatile organic hydrocarbons (VOCs) and gases as adsorptives. The results show preferential adsorption of toluene vapor over cyclohexane vapor. The adsorption capacity toward toluene is 5.02 mmol/g for KCrBiTe3, 5.58 mmol/g for KZnBiTe3 and 7.89 mmol/g for KFeBiTe3. Preferential adsorption of CO2 over CH4 or H2 was observed for the chalcogels: KCrBiTe3 (CO2/H2: 175, CO2/CH4: 50), KZnBiTe3 (CO2/H2: 180 and CO2/CH4: 60) and KFeBiTe3 (CO2/H2: 225 and CO2/CH4: 65).

  9. The chemokines CCL11, CCL20, CCL21, and CCL24 are preferentially expressed in polarized human secondary lymphoid follicles.

    Science.gov (United States)

    Buri, Caroline; Gutersohn, Andreas; Hauser, Chantal; Kappeler, Andreas; Mueller, Christoph

    2004-10-01

    Chemokines regulate cellular trafficking to and from lymphoid follicles. Here, the distribution pattern of four CCL chemokines is defined by in situ hybridization in human lymphoid follicles from tonsils and lymph nodes (LNs) of newborns and adults. Cells expressing CCL11 (eotaxin) and CCL20 (Exodus) were preferentially located within follicles, while cells expressing CCL21 (secondary lymphoid-tissue chemokine) and CCL24 (eotaxin-2) mRNA were almost exclusively found in the perifollicular areas. Hence, the two CCR3-binding chemokines, CCL11 and CCL24, showed a mutually exclusive expression pattern in the intra- and extra-follicular areas, respectively. Chemokine gene expression paralleled follicular maturation: in tonsils, where approximately 80% of follicles are polarized, CCL11 and CCL20 mRNA-positive cells were detected more frequently than in lymph nodes from adults, where about half of follicles are non-polarized. No intrafollicular chemokine expression was detectable in the primary follicles from newborns. Extrafollicular cells expressing CCL21 and CCL24 were again more frequent in tonsils than in LNs from adults. The observed preferential presence of cells expressing CC chemokines in polarized human lymphoid follicles indicates that chemokines are not only instrumental in the induction of follicle formation, but may also be involved in their further differentiation.

  10. Preferential heating of oxygen 5{sup +} ions by finite-amplitude oblique Alfvén waves

    Energy Technology Data Exchange (ETDEWEB)

    Maneva, Yana G.; Poedts, Stefaan [Centre for mathematical Plasma Astrophysics, KU Leuven, B-3001 Leuven (Belgium); Viñas, Adolfo [NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, 20771 MD (United States); Araneda, Jaime [Departamento de Física, Universidad de Concepción, Casilla 160 - C, Concepción (Chile)

    2016-03-25

    Minor ions in the fast solar wind are known to have higher temperatures and to flow faster than protons in the interplanetary space. In this study we combine previous research on parametric instability theory and 2.5D hybrid simulations to study the onset of preferential heating of Oxygen 5{sup +} ions by large-scale finite-amplitude Alfvén waves in the collisionless fast solar wind. We consider initially non-drifting isotropic multi-species plasma, consisting of isothermal massless fluid electrons, kinetic protons and kinetic Oxygen 5{sup +} ions. The external energy source for the plasma heating and energization are oblique monochromatic Alfvén-cyclotron waves. The waves have been created by rotating the direction of initial parallel pump, which is a solution of the multi-fluid plasma dispersion relation. We consider propagation angles θ ≤ 30°. The obliquely propagating Alfvén pump waves lead to strong diffusion in the ion phase space, resulting in highly anisotropic heavy ion velocity distribution functions and proton beams. We discuss the application of the model to the problems of preferential heating of minor ions in the solar corona and the fast solar wind.

  11. [Left- or right-handed: the effect of a preferential use of one hand or the other on dental hygiene].

    Science.gov (United States)

    Eleveld, C A; Schuller, A A

    2016-02-01

    A research project investigated the extent to which a preferential use of one hand or the other has an effect on dental hygiene on the left or right side of the mouth. The study made use of epidemiological dental-care data from the Netherlands Organisation for Applied Scientific Research and of data from a dental practice specifically collected for this project. The results revealed that among a population which is 85-90% right-handed, statistically significantly more dental plaque was found on the right side of the mouth than on the left. A separate study revealed the prevalence of statistically significantly more dental plaque on the right side than on the left among right-handed people and, among left-handed people, a non-statistically significant trend of more dental plaque on the left than the right. It is concluded that dental hygiene on the left side and the right side of the mouth is very likely to be dependent on the preferential use of one hand or the other. The differences between the left side of the mouth and right among left- and right-handed people are, however, so small that it is questionable whether these should be taken into consideration in giving instructions about dental hygiene.

  12. Growing Homophilic Networks Are Natural Navigable Small Worlds.

    Science.gov (United States)

    Malkov, Yury A; Ponomarenko, Alexander

    2016-01-01

    Navigability, an ability to find a logarithmically short path between elements using only local information, is one of the most fascinating properties of real-life networks. However, the exact mechanism responsible for the formation of navigation properties remained unknown. We show that navigability can be achieved by using only two ingredients present in the majority of networks: network growth and local homophily, giving a persuasive answer how the navigation appears in real-life networks. A very simple algorithm produces hierarchical self-similar optimally wired navigable small world networks with exponential degree distribution by using only local information. Adding preferential attachment produces a scale-free network which has shorter greedy paths, but worse (power law) scaling of the information extraction locality (algorithmic complexity of a search). Introducing saturation of the preferential attachment leads to truncated scale-free degree distribution that offers a good tradeoff between these parameters and can be useful for practical applications. Several features of the model are observed in real-life networks, in particular in the brain neural networks, supporting the earlier suggestions that they are navigable.

  13. Growing Homophilic Networks Are Natural Navigable Small Worlds.

    Directory of Open Access Journals (Sweden)

    Yury A Malkov

    Full Text Available Navigability, an ability to find a logarithmically short path between elements using only local information, is one of the most fascinating properties of real-life networks. However, the exact mechanism responsible for the formation of navigation properties remained unknown. We show that navigability can be achieved by using only two ingredients present in the majority of networks: network growth and local homophily, giving a persuasive answer how the navigation appears in real-life networks. A very simple algorithm produces hierarchical self-similar optimally wired navigable small world networks with exponential degree distribution by using only local information. Adding preferential attachment produces a scale-free network which has shorter greedy paths, but worse (power law scaling of the information extraction locality (algorithmic complexity of a search. Introducing saturation of the preferential attachment leads to truncated scale-free degree distribution that offers a good tradeoff between these parameters and can be useful for practical applications. Several features of the model are observed in real-life networks, in particular in the brain neural networks, supporting the earlier suggestions that they are navigable.

  14. Growing Up Or Growing Old? Cellular Aging Linked With Testosterone Reactivity To Stress In Youth

    Science.gov (United States)

    Drury, Stacy S.; Shirtcliff, Elizabeth A.; Shachet, Andrew; Phan, Jenny; Mabile, Emily; Brett, Zoë H.; Wren, Michael; Esteves, Kyle; Theall, Katherine P.

    2014-01-01

    Background Given the established relation between testosterone and aging in older adults, we tested whether buccal telomere length (TL), an established cellular biomarker of aging, was associated with testosterone levels in youth. Methods Children, mean age 10.2 years, were recruited from the greater New Orleans area and salivary testosterone was measured during both an acute stressor and diurnally. Buccal TL was measured using monochrome multiplex quantitative real-time PCR (MMQ-PCR). Testosterone and telomere length data was available on 77 individuals. The association between buccal TL and testosterone was tested using multivariate Generalized Estimating Equations (GEE) to account for clustering of children within families. Results Greater peak testosterone levels (β=-0.87, p < 0.01) and slower recovery (β=-0.56, p < 0.01) and reactivity (β = -1.22, p < 0.01) following a social stressor were significantly associated with shorter buccal TL after controlling for parental age at conception, child age, sex, sociodemographic factors and puberty. No association was initially present between diurnal measurements of testosterone or morning basal testosterone levels and buccal TL. Sex significantly moderated the relation between testosterone reactivity and buccal TL. Conclusions The association between testosterone and buccal TL supports gonadal maturation as a developmentally sensitive biomarker of aging within youth. As stress levels of testosterone were significantly associated with buccal TL, these findings are consistent with the growing literature linking stress exposure and accelerated maturation. The lack of association of diurnal testosterone or morning basal levels with buccal TL bolsters the notion of a shared stress-related maturational mechanism between cellular stress and the hypothalamic pituitary gonadal (HPG) axis. These data provide novel evidence supporting the interaction of aging, physiologic stress and cellular processes as an underlying

  15. Morphoelastic rods. Part I: A single growing elastic rod

    KAUST Repository

    Moulton, D.E.

    2013-02-01

    A theory for the dynamics and statics of growing elastic rods is presented. First, a single growing rod is considered and the formalism of three-dimensional multiplicative decomposition of morphoelasticity is used to describe the bulk growth of Kirchhoff elastic rods. Possible constitutive laws for growth are discussed and analysed. Second, a rod constrained or glued to a rigid substrate is considered, with the mismatch between the attachment site and the growing rod inducing stress. This stress can eventually lead to instability, bifurcation, and buckling. © 2012 Elsevier Ltd. All rights reserved.

  16. Growing older in the context of needing geriatric assessment

    DEFF Research Database (Denmark)

    Esbensen, Bente Appel; Hvitved, Ida; Andersen, Hanne Elkjær

    2016-01-01

    significant and (v) considerations about the end of life as a component of growing older. The essence was defined as: illness essential for the experience of growing older and pointed to the experience of growing older that highlighted that experiencing illnesses and limitations served as reminders...... methodology. RESULTS: The results led to an overall essence and five themes. The five themes were identified: (i) considerations to avoid weakness, (ii) compensation for the inability to perform certain activities, (iii) aides - a symbol of freedom or limitation, (iv) lifestyle considered being particularly...

  17. Morphoelastic rods. Part I: A single growing elastic rod

    KAUST Repository

    Moulton, D.E.; Lessinnes, T.; Goriely, A.

    2013-01-01

    A theory for the dynamics and statics of growing elastic rods is presented. First, a single growing rod is considered and the formalism of three-dimensional multiplicative decomposition of morphoelasticity is used to describe the bulk growth of Kirchhoff elastic rods. Possible constitutive laws for growth are discussed and analysed. Second, a rod constrained or glued to a rigid substrate is considered, with the mismatch between the attachment site and the growing rod inducing stress. This stress can eventually lead to instability, bifurcation, and buckling. © 2012 Elsevier Ltd. All rights reserved.

  18. China's Soft Power and Growing Influence in Southeast Asia

    National Research Council Canada - National Science Library

    Hwang, Edward F

    2008-01-01

    .... By no means is China able to surpass the United States soft power capabilities. As China's economy and influence in the region continue to grow however, China as an alternative to the United States can become a reality...

  19. Climate Prediction Center Weekly Corn Growing Degree Days

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A corn growing degree day (GDD) is an index used to express crop maturity. The index is computed by subtracting a base temperature of 50?F from the average of the...

  20. Nursery growing of some apple varieties using different grafting ...

    African Journals Online (AJOL)

    Yomi

    2011-12-21

    Dec 21, 2011 ... conditions differences were been determinated according to rootstocks ... been grown since pre-historic times in Asia and Europe ... apple growing country after China and the USA. ... He also pointed out that high cost of work.

  1. Reasons for the Fast Growing Seawater Desalination Capacity in Algeria

    KAUST Repository

    Drouiche, Nadjib; Ghaffour, NorEddine; Naceur, Mohamed Wahib; Mahmoudi, Hacè ne; Ouslimane, Tarik

    2011-01-01

    growing markets. Five desalination plants, including the Africa's largest seawater reverse osmosis project with a total capacity of 200,000 m3 per day, are already in operation and the remaining projects are either under construction or in commissioning

  2. Improving women and youth livelihoods through small and growing ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Small and growing businesses (SGBs) play an important role in lifting people out ... to advance business objectives and development goals simultaneously, thus ... impact of SGBs through a catalyst fund for partnerships between researchers ...

  3. Leadership Makes a Difference Growing Federal Civilian Leaders

    National Research Council Canada - National Science Library

    Muellerweiss, Alice

    2008-01-01

    .... Research indicates that currently our government does not grow effective leaders. Often those "rising to the top" are technical experts with minimal leadership experiences, mostly unacquainted with the fundamentals of leadership...

  4. Eucalypt pests and diseases: growing threats to plantation productivity

    African Journals Online (AJOL)

    Eucalypt pests and diseases: growing threats to plantation productivity. ... Southern Forests: a Journal of Forest Science ... plantations, it is clear that separation of the trees from their natural enemies has resulted in exceptional performance.

  5. Electronic Waste: A Growing Challenge In Nigeria | Ukem | Global ...

    African Journals Online (AJOL)

    Global Journal of Pure and Applied Sciences ... growing problem of electronic waste from the Nigerian perspective, and highlights factors that can militate ... equipment, electronic waste, recycling, environmental pollution, waste management.

  6. Engineering a wild fast-growing Mycoplasma bacterium to generate ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2018-01-12

    Jan 12, 2018 ... The CCPP bacterium causes sick animals to experience severe symptoms ... because antibiotic treatment does not eliminate the responsible bacterium. ... To develop a fast growing CCPP vaccine for cheaper production and ...

  7. Growing axons analysis by using Granulometric Size Distribution

    International Nuclear Information System (INIS)

    Gonzalez, Mariela A; Ballarin, Virginia L; Rapacioli, Melina; CelIn, A R; Sanchez, V; Flores, V

    2011-01-01

    Neurite growth (neuritogenesis) in vitro is a common methodology in the field of developmental neurobiology. Morphological analyses of growing neurites are usually difficult because their thinness and low contrast usually prevent to observe clearly their shape, number, length and spatial orientation. This paper presents the use of the granulometric size distribution in order to automatically obtain information about the shape, size and spatial orientation of growing axons in tissue cultures. The results here presented show that the granulometric size distribution results in a very useful morphological tool since it allows the automatic detection of growing axons and the precise characterization of a relevant parameter indicative of the axonal growth spatial orientation such as the quantification of the angle of deviation of the growing direction. The developed algorithms automatically quantify this orientation by facilitating the analysis of these images, which is important given the large number of images that need to be processed for this type of study.

  8. But How Do You Grow Plants Without Dirt?

    Science.gov (United States)

    Howells, Ronald F.

    1978-01-01

    Describes a class project on hydroponic farming (growing plants in water and in organic nutrients rather than dirt). Students formed a corporation to raise necessary funds and paid dividends from the proceeds earned selling the crop. (JMB)

  9. Modified methods for growing 3-D skin equivalents: an update.

    Science.gov (United States)

    Lamb, Rebecca; Ambler, Carrie A

    2014-01-01

    Artificial epidermis can be reconstituted in vitro by seeding primary epidermal cells (keratinocytes) onto a supportive substrate and then growing the developing skin equivalent at the air-liquid interface. In vitro skin models are widely used to study skin biology and for industrial drug and cosmetic testing. Here, we describe updated methods for growing 3-dimensional skin equivalents using de-vitalized, de-epidermalized dermis (DED) substrates including methods for DED substrate preparation, cell seeding, growth conditions, and fixation procedures.

  10. Food-Growing, Air- And Water-Cleaning Module

    Science.gov (United States)

    Sauer, R. L.; Scheld, H. W.; Mafnuson, J. W.

    1988-01-01

    Apparatus produces fresh vegetables and removes pollutants from air. Hydroponic apparatus performs dual function of growing fresh vegetables and purifying air and water. Leafy vegetables rooted in granular growth medium grow in light of fluorescent lamps. Air flowing over leaves supplies carbon dioxide and receives fresh oxygen from them. Adaptable to production of food and cleaning of air and water in closed environments as in underwater research stations and submarines.

  11. Blueprint and Approach to Grow Revenue in Small Technology Companies

    Directory of Open Access Journals (Sweden)

    Tony Bailetti

    2010-05-01

    Full Text Available This article examines a new approach to grow the revenue of small technology companies and technology startups. We name this new approach the business ecosystem approach. The article is organized into five sections. The first section provides a blueprint to grow revenue and an inventory of growth formulas that top management teams of small technology companies and founders of startups find useful. The second section briefly defines business ecosystems, keystones and platforms. The third section describes the business ecosystem approach to grow the revenue of small technology companies and technology startups. It compares the traditional and business ecosystem approaches to growing revenue; identifies when the business ecosystem approach works better than the traditional approach; explains what small companies and startups need to do to grow revenue using the business ecosystem approach; and describes the benefits and risks of implementing the business ecosystem approach. The fourth section compares three approaches to growing revenue and highlights the differences between i business ecosystems and development communities and ii the business ecosystem approach and outsourcing. The fifth section identifies the key decisions a small technology company or technology startup needs to make to become the keystone that anchors a business ecosystem.

  12. Study of preferential sputtering and segregation effects on the surface composition of Al-Pd-Mn quasi-crystals

    Energy Technology Data Exchange (ETDEWEB)

    Samavat, F.; Gladys, M.; Jenks, C.; Lograsso, T.; King, M.; O' Connor, D.

    2008-02-25

    Using 2 keV He+ and Ne+ low-energy ion scattering (LEIS), it was found that the Al/Pd concentration ratio at the surface of a nominally Al69.9Pd20.5Mn9.6 quasi-crystal decreases to a steady-state value under bombardment as a result of preferential sputtering. Sputtering of an annealed surface results in a significant increase in Mn concentration on the surface which remained at annealing temperatures below 575 K. Variations of the Mn/Pd and Al/Pd ratios have been measured by LEIS as a function of temperature in the range 295-975 K for clean-annealed and sputtered surfaces. The results show that Al/Pd ratio does not significantly change from 295 to 575 K for both He+ and Ne+ but increases with sample temperatures up to 875 K.

  13. KFeSbTe3: A quaternary chalcogenide aerogel for preferential adsorption of polarizable hydrocarbons and gases

    KAUST Repository

    Ahmed, Ejaz

    2015-01-01

    The first telluride-based quaternary aerogel KFeSbTe3 is synthesized by a sol-gel metathesis reaction between Fe(OAc)2 and K3SbTe3 in dimethyl formamide. The aerogel has an exceptionally large surface area 652 m2 g-1 which is amongst the highest reported for chalcogenide-based aerogels. This predominantly mesoporous material shows preferential adsorption for toluene vapors over cyclohexane or cyclopentane and CO2 over CH4 or H2. The remarkably high adsorption capacity for toluene (9.31 mmol g-1) and high selectivity for gases (CO2/H2: 121 and CO2/CH4: 75) suggest a potential use of such materials in adsorption-based separation processes for the effective purification of hydrocarbons and gases. © The Royal Society of Chemistry 2015.

  14. Xanthophylls are preferentially taken up compared with beta-carotene by retinal cells via a SRBI-dependent mechanism.

    Science.gov (United States)

    During, Alexandrine; Doraiswamy, Sundari; Harrison, Earl H

    2008-08-01

    The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. beta-carotene(beta-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7-9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than beta-C (P xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for beta-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina.

  15. Xanthophylls are preferentially taken up compared with β-carotene by retinal cells via a SRBI-dependent mechanism*1

    Science.gov (United States)

    During, Alexandrine; Doraiswamy, Sundari; Harrison, Earl H.

    2008-01-01

    The purpose of this study was to investigate the mechanisms by which carotenoids [xanthophylls vs. β-carotene(β-C)] are taken up by retinal pigment epithelial (RPE) cells. The human RPE cell line, ARPE-19, was used. When ARPE-19 cells were fully differentiated (7–9 weeks), the xanthophylls lutein (LUT) and zeaxanthin (ZEA) were taken up by cells to an extent 2-fold higher than β-C (P xanthophylls versus the carotene by a process that appears to be entirely SR-BI-dependent for ZEA and partly so for β-C. This mechanism may explain, in part, the preferential accumulation of xanthophylls in the macula of the retina. PMID:18424859

  16. TNP-specific Lyt-2+ cytolytic T cell clones preferentially respond to TNP-conjugated epidermal cells

    International Nuclear Information System (INIS)

    Shimada, S.; Katz, S.I.

    1985-01-01

    A most effective method for the induction of hapten-specific allergic contact sensitivity (CS) is via epicutaneous application of the hapten. Another effective method is by the administration of haptenated epidermal cells (EC) subcutaneously. The latter method induces more intense and longer lasting CS than does the subcutaneous administration of haptenated spleen cells (SC). Thus, there may be something unique about EC which, when haptenated, allows them to generate effector cells more effectively than do SC. The authors therefore, attempted to generate T cell clones that were both hapten- and epidermal-specific. Four days after painting mice with 7% trinitrochlorobenzene, draining lymph node cells were obtained and T cells were purified. These cells were co-cultured with trinitrophenylated (TNP) Langerhans cell-enriched EC. After 4 days, cells were harvested and rested on non-TNP-conjugated EC. The cells were restimulated and rested three times, and were then cloned by limiting dilution with added interleukin 2, which was then continually added. Proliferation of T cells was assessed by [ 3 H]-thymidine incorporation. Cytotoxicity assays utilized TNP-conjugated concanavalin A SC blasts or EC as targets. Clones A-2 and E-4 are Thy-1+, Lyt-2+, and L3T4-, and TNP-specific. In contrast to noncloned TNP-specific T cells, the clones proliferate preferentially in response to TNP-EC rather than TNP-SC. Also in contrast to noncloned T cells, the clones were preferentially cytotoxic for TNP-EC; compared to TNP-SC, there was an eight- to 32-fold increase in killing when TNP-EC were used as targets. Clones A-2 and E-4 therefore exhibit hapten and epidermal specificity

  17. Manipulation of GABA in the ventral pallidum, but not the nucleus accumbens, induces intense, preferential, fat consumption in rats.

    Science.gov (United States)

    Covelo, Ignacio R; Patel, Zaid I; Luviano, Jennifer A; Stratford, Thomas R; Wirtshafter, David

    2014-08-15

    Injections of the GABAA antagonist bicuculline into the medial ventral pallidum (VPm) induce marked increases in food intake, but nothing is known about the way in which these injections alter the distribution of intake in a macronutrient selection situation. We investigated this topic by adapting rats to a diet containing independent sources of protein, carbohydrate and fat, and then examining the effects of intra-VPm bicuculline on diet selection. Under these conditions, bicuculline produced a massive, preferential increase in fat intake with subjects consuming a mean of 97% of their calories from fat. Furthermore, all treated subjects ate fat before any other macronutrient, suggesting that the animals' behavior was directed selectively toward this dietary component even before consumption had begun. Similar effects were not observed following food deprivation, which exerted its largest effect on carbohydrate intake. To compare the intra-VPm bicuculline response to that seen after activation of GABA receptors in the nucleus accumbens shell (AcbSh), a major source of projections to the VPm, we conducted similar experiments with intra-AcbSh injections of muscimol and baclofen. These injections also enhanced food intake, but did not reproduce the selective preference for fat seen after intra-VPm bicuculline. These experiments provide the first demonstration of preferential enhancement of fat intake following manipulations of a nonpeptide neurotransmitter. Since mean intakes of fat under baseline conditions and after deprivation tended to be lower than those of carbohydrates, it seems unlikely that the effects of intra-VPm bicuculline are related to the intrinsic "rewarding" properties of fat, but might rather reflect the induction of a state of "fat craving." Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy.

    Directory of Open Access Journals (Sweden)

    Degang Yang

    2016-01-01

    Full Text Available The persistence of Mycobacterium leprae (M. leprae infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions.Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta, IL-6, tumor necrosis factor alpha (TNF-alpha and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings.Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity.

  19. Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy.

    Science.gov (United States)

    Yang, Degang; Shui, Tiejun; Miranda, Jake W; Gilson, Danny J; Song, Zhengyu; Chen, Jia; Shi, Chao; Zhu, Jianyu; Yang, Jun; Jing, Zhichun

    2016-01-01

    The persistence of Mycobacterium leprae (M. leprae) infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions. Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNF-alpha) and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg) cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma) expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings. Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity.

  20. Analysis of a preferential action of α-amylase from B. licheniformis towards amorphous regions of waxy maize starch.

    Science.gov (United States)

    Foresti, María Laura; Williams, María del Pilar; Martínez-García, Ricardo; Vázquez, Analía

    2014-02-15

    Waxy maize starch was subjected to α-amylase (Bacillus licheniformis) hydrolysis in buffered medium to determine the evolution of reaction in quantitative terms and also in terms of the morphology and crystallinity of the partially hydrolyzed starch granules. Gathered data allowed studying the pattern of action of this α-amylase over waxy maize starch granules, with particular focus on a preferential hydrolysis of the amorphous regions of starch. Results showed that waxy maize starch hydrolysis followed a two-stage kinetic profile with an initial stage characterized by high reaction rate, followed by a slower second stage. The change of hydrolysis rate occurred at approximately 6h of reaction, a time for which X-ray diffraction data quantitatively analyzed by three different techniques showed a maximum of crystallinity in partially hydrolyzed granules. Scanning electron microscopy images illustrated the action of α-amylases which implied the exoerosion of the granules surface, the entry of α-amylases into the granules through radial channels, their endoerosion towards the granule exterior, and their fragmentation. Fragmentation of waxy maize starch granules revealed internal layered structures of starch which were interpreted as hydrolyzed/non-hydrolyzed growth rings. Under the conditions chosen, kinetic, electron microscopy and X-ray data all gave evidence of a preferential action of α-amylase from Bacillus licheniformis towards the less ordered regions of waxy maize starch. Results showed that, provided the proper hydrolysis time is chosen, starch granules with increased crystallinity can be obtained by a pure enzymatic treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.