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Sample records for expanded hammerhead ribozymes

  1. Artificial hammerhead ribozymes: engineering and applications

    International Nuclear Information System (INIS)

    Vorobjeva, M A; Davydova, A S; Venyaminova, Aliya G

    2011-01-01

    The properties of hammerhead ribozymes are described. Various hammerhead ribozyme constructs for target RNA cleavage were considered. Approaches to enhancement of the stability of artificial ribozymes in biological media and to regulation of the catalytic activity of hammerhead ribozymes using effector molecules are described. The effect of ribozymes on extended structured natural RNAs is discussed. Applications of artificial hammerhead ribozymes as inhibitors of gene expression at matrix RNA level were considered.

  2. Ionic interactions and the global conformations of the hammerhead ribozyme

    DEFF Research Database (Denmark)

    Bassi, G S; Møllegaard, N E; Murchie, A I

    1995-01-01

    Here we investigate the global conformation of the hammerhead ribozyme. Electrophoretic studies demonstrate that the structure is folded in response to the concentration and type of ions present. Folding based on colinear alignment of arms II and III is suggested, with a variable angle subtended ...

  3. Capturing hammerhead ribozyme structures in action by modulating general base catalysis.

    Directory of Open Access Journals (Sweden)

    Young-In Chi

    2008-09-01

    Full Text Available We have obtained precatalytic (enzyme-substrate complex and postcatalytic (enzyme-product complex crystal structures of an active full-length hammerhead RNA that cleaves in the crystal. Using the natural satellite tobacco ringspot virus hammerhead RNA sequence, the self-cleavage reaction was modulated by substituting the general base of the ribozyme, G12, with A12, a purine variant with a much lower pKa that does not significantly perturb the ribozyme's atomic structure. The active, but slowly cleaving, ribozyme thus permitted isolation of enzyme-substrate and enzyme-product complexes without modifying the nucleophile or leaving group of the cleavage reaction, nor any other aspect of the substrate. The predissociation enzyme-product complex structure reveals RNA and metal ion interactions potentially relevant to transition-state stabilization that are absent in precatalytic structures.

  4. Folding of the natural hammerhead ribozyme is enhanced by interaction of auxiliary elements

    Science.gov (United States)

    PENEDO, J. CARLOS; WILSON, TIMOTHY J.; JAYASENA, SUMEDHA D.; KHVOROVA, ANASTASIA; LILLEY, DAVID M.J.

    2004-01-01

    It has been shown that the activity of the hammerhead ribozyme at μM magnesium ion concentrations is markedly increased by the inclusion of loops in helices I and II. We have studied the effect of such loops on the magnesium ion-induced folding of the ribozyme, using fluorescence resonance energy transfer. We find that with the loops in place, folding into the active conformation occurs in a single step, in the μM range of magnesium ion concentration. Disruption of the loop–loop interaction leads to a reversion to two-step folding, with the second stage requiring mM concentrations of magnesium ion. Sodium ions also promote the folding of the natural form of the ribozyme at high concentrations, but the folding occurs as a two-stage process. The loops clearly act as important auxiliary elements in the function of the ribozyme, permitting folding to occur efficiently under physiological conditions. PMID:15100442

  5. Two Divalent Metal Ions and Conformational Changes Play Roles in the Hammerhead Ribozyme Cleavage Reaction

    Science.gov (United States)

    Mir, Aamir; Chen, Ji; Robinson, Kyle; Lendy, Emma; Goodman, Jaclyn; Neau, David; Golden, Barbara L.

    2016-01-01

    The hammerhead ribozyme is a self-cleaving RNA broadly dispersed across all kingdoms of life. Although it was the first of the small, nucleolytic ribozymes discovered, the mechanism by which it catalyzes its reaction remains elusive. The nucleobase of G12 is well positioned to be a general base, but it is unclear if or how this guanine base becomes activated for proton transfer. Metal ions have been implicated in the chemical mechanism, but no interactions between divalent metal ions and the cleavage site have been observed crystallographically. To better understand how this ribozyme functions, we have solved crystal structures of wild-type and G12A mutant ribozymes. We observe a pH-dependent conformational change centered around G12, consistent with this nucleotide becoming deprotonated. Crystallographic and kinetic analysis of the G12A mutant reveals a Zn2+ specificity switch suggesting a direct interaction between a divalent metal ion and the purine at position 12. The metal ion specificity switch and the pH–rate profile of the G12A mutant suggest that the minor imino tautomer of A12 serves as the general base in the mutant ribozyme. We propose a model in which the hammerhead ribozyme rearranges prior to the cleavage reaction, positioning two divalent metal ions in the process. The first metal ion, positioned near G12, becomes directly coordinated to the O6 keto oxygen, to lower the pKa of the general base and organize the active site. The second metal ion, positioned near G10.1, bridges the N7 of G10.1 and the scissile phosphate and may participate directly in the cleavage reaction. PMID:26398724

  6. Targeted cleavage of hepatitis E virus 3' end RNA mediated by hammerhead ribozymes inhibits viral RNA replication

    International Nuclear Information System (INIS)

    Sriram, Bandi; Thakral, Deepshi; Panda, Subrat Kumar

    2003-01-01

    The 3' end of hepatitis E virus (HEV) contains cis-acting regulatory element, which plays an important role in viral replication. To develop specific replication inhibitor at the molecular level, mono- and di-hammerhead ribozymes (Rz) were designed and synthesized against the conserved 3' end sequences of HEV, which cleave at nucleotide positions 7125 and 7112/7125, respectively. Di-hammerhead ribozyme with two catalytic motifs in tandem was designed to cleave simultaneously at two sites spaced 13 nucleotides apart, which increases the overall cleavage efficiency and prevents the development of escape mutants. Specific cleavage products were obtained with both the ribozymes in vitro at physiological conditions. The inactive control ribozymes showed no cleavage. The ribozymes showed specific inhibition of HEV 3' end fused-luciferase reporter gene expression by ∼37 and ∼60%, respectively in HepG2 cells. These results demonstrate a feasible approach to inhibit the HEV replication to a limited extent by targeting the cis-acting 3' end of HEV with hammerhead ribozymes

  7. Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds

    Directory of Open Access Journals (Sweden)

    Shu-ichi Nakano

    2014-01-01

    Full Text Available Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol, small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.

  8. Heat capacity changes in RNA folding: application of perturbation theory to hammerhead ribozyme cold denaturation.

    Science.gov (United States)

    Mikulecky, Peter J; Feig, Andrew L

    2004-01-01

    In proteins, empirical correlations have shown that changes in heat capacity (DeltaC(P)) scale linearly with the hydrophobic surface area buried upon folding. The influence of DeltaC(P) on RNA folding has been widely overlooked and is poorly understood. In addition to considerations of solvent reorganization, electrostatic effects might contribute to DeltaC(P)s of folding in polyanionic species such as RNAs. Here, we employ a perturbation method based on electrostatic theory to probe the hot and cold denaturation behavior of the hammerhead ribozyme. This treatment avoids much of the error associated with imposing two-state folding models on non-two-state systems. Ribozyme stability is perturbed across a matrix of solvent conditions by varying the concentration of NaCl and methanol co-solvent. Temperature-dependent unfolding is then monitored by circular dichroism spectroscopy. The resulting array of unfolding transitions can be used to calculate a DeltaC(P) of folding that accurately predicts the observed cold denaturation temperature. We confirm the accuracy of the calculated DeltaC(P) by using isothermal titration calorimetry, and also demonstrate a methanol-dependence of the DeltaC(P). We weigh the strengths and limitations of this method for determining DeltaC(P) values. Finally, we discuss the data in light of the physical origins of the DeltaC(P)s for RNA folding and consider their impact on biological function.

  9. Design and kinetic analysis of hammerhead ribozyme and DNAzyme that specifically cleave TEL-AML1 chimeric mRNA

    International Nuclear Information System (INIS)

    Choi, Woo-Hyung; Choi, Bo-Ra; Kim, Jae Hyun; Yeo, Woon-Seok; Oh, Sangtaek; Kim, Dong-Eun

    2008-01-01

    In order to develop the oligonucleotides to abolish an expression of TEL-AML1 chimeric RNA, which is a genetic aberration that causes the acute lymphoblastic leukemia (ALL), hammerhead ribozymes and deoxyoligoribozymes that can specifically cleave TEL-AML1 fusion RNA were designed. Constructs of the deoxyribozyme with an asymmetric substrate binding arm (Dz26) and the hammerhead ribozyme with a 4 nt-bulged substrate binding arm in the stem III (buRz28) were able to cleave TEL-AML1 chimeric RNA specifically at sites close to the junction in vitro, without cleaving the normal TEL and AML1 RNA. Single-turnover kinetic analysis under enzyme-excess condition revealed that the buRz28 is superior to the Dz26 in terms of substrate binding and RNA-cleavage. In conjunction with current progress in a gene-delivery technology, the designed oligonucleotides that specifically cleave the TEL-AML1 chimeric mRNA are hoped to be applicable for the treatment of ALL in vivo

  10. Phylogenetic footprinting of non-coding RNA: hammerhead ribozyme sequences in a satellite DNA family of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae

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    Venanzetti Federica

    2010-01-01

    Full Text Available Abstract Background The great variety in sequence, length, complexity, and abundance of satellite DNA has made it difficult to ascribe any function to this genome component. Recent studies have shown that satellite DNA can be transcribed and be involved in regulation of chromatin structure and gene expression. Some satellite DNAs, such as the pDo500 sequence family in Dolichopoda cave crickets, have a catalytic hammerhead (HH ribozyme structure and activity embedded within each repeat. Results We assessed the phylogenetic footprints of the HH ribozyme within the pDo500 sequences from 38 different populations representing 12 species of Dolichopoda. The HH region was significantly more conserved than the non-hammerhead (NHH region of the pDo500 repeat. In addition, stems were more conserved than loops. In stems, several compensatory mutations were detected that maintain base pairing. The core region of the HH ribozyme was affected by very few nucleotide substitutions and the cleavage position was altered only once among 198 sequences. RNA folding of the HH sequences revealed that a potentially active HH ribozyme can be found in most of the Dolichopoda populations and species. Conclusions The phylogenetic footprints suggest that the HH region of the pDo500 sequence family is selected for function in Dolichopoda cave crickets. However, the functional role of HH ribozymes in eukaryotic organisms is unclear. The possible functions have been related to trans cleavage of an RNA target by a ribonucleoprotein and regulation of gene expression. Whether the HH ribozyme in Dolichopoda is involved in similar functions remains to be investigated. Future studies need to demonstrate how the observed nucleotide changes and evolutionary constraint have affected the catalytic efficiency of the hammerhead.

  11. Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid–base catalysis

    Science.gov (United States)

    Schultz, Eric P.; Vasquez, Ernesto E.; Scott, William G.

    2014-01-01

    The hammerhead ribozyme catalyzes RNA cleavage via acid–base catalysis. Whether it does so by general acid–base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid–base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK a of the substituted purine; in both cases inosine, which is similar to G in pK a and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the

  12. Structural and catalytic effects of an invariant purine substitution in the hammerhead ribozyme: implications for the mechanism of acid-base catalysis.

    Science.gov (United States)

    Schultz, Eric P; Vasquez, Ernesto E; Scott, William G

    2014-09-01

    The hammerhead ribozyme catalyzes RNA cleavage via acid-base catalysis. Whether it does so by general acid-base catalysis, in which the RNA itself donates and abstracts protons in the transition state, as is typically assumed, or by specific acid-base catalysis, in which the RNA plays a structural role and proton transfer is mediated by active-site water molecules, is unknown. Previous biochemical and crystallographic experiments implicate an invariant purine in the active site, G12, as the general base. However, G12 may play a structural role consistent with specific base catalysis. To better understand the role of G12 in the mechanism of hammerhead catalysis, a 2.2 Å resolution crystal structure of a hammerhead ribozyme from Schistosoma mansoni with a purine substituted for G12 in the active site of the ribozyme was obtained. Comparison of this structure (PDB entry 3zd4), in which A12 is substituted for G, with three previously determined structures that now serve as important experimental controls, allows the identification of structural perturbations that are owing to the purine substitution itself. Kinetic measurements for G12 purine-substituted schistosomal hammerheads confirm a previously observed dependence of rate on the pK(a) of the substituted purine; in both cases inosine, which is similar to G in pK(a) and hydrogen-bonding properties, is unexpectedly inactive. Structural comparisons indicate that this may primarily be owing to the lack of the exocyclic 2-amino group in the G12A and G12I substitutions and its structural effect upon both the nucleotide base and phosphate of A9. The latter involves the perturbation of a previously identified and well characterized metal ion-binding site known to be catalytically important in both minimal and full-length hammerhead ribozyme sequences. The results permit it to be suggested that G12 plays an important role in stabilizing the active-site structure. This result, although not inconsistent with the potential

  13. Spiegelzymes® mirror-image hammerhead ribozymes and mirror-image DNAzymes, an alternative to siRNAs and microRNAs to cleave mRNAs in vivo?

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    Eliza Wyszko

    Full Text Available With the discovery of small non-coding RNA (ncRNA molecules as regulators for cellular processes, it became intriguing to develop technologies by which these regulators can be applied in molecular biology and molecular medicine. The application of ncRNAs has significantly increased our knowledge about the regulation and functions of a number of proteins in the cell. It is surprising that similar successes in applying these small ncRNAs in biotechnology and molecular medicine have so far been very limited. The reasons for these observations may lie in the high complexity in which these RNA regulators function in the cells and problems with their delivery, stability and specificity. Recently, we have described mirror-image hammerhead ribozymes and DNAzymes (Spiegelzymes® which can sequence-specifically hydrolyse mirror-image nucleic acids, such as our mirror-image aptamers (Spiegelmers discovered earlier. In this paper, we show for the first time that Spiegelzymes are capable of recognising complementary enantiomeric substrates (D-nucleic acids, and that they efficiently hydrolyse them at submillimolar magnesium concentrations and at physiologically relevant conditions. The Spiegelzymes are very stable in human sera, and do not require any protein factors for their function. They have the additional advantages of being non-toxic and non-immunogenic. The Spiegelzymes can be used for RNA silencing and also as therapeutic and diagnostic tools in medicine. We performed extensive three-dimensional molecular modelling experiments with mirror-image hammerhead ribozymes and DNAzymes interacting with D-RNA targets. We propose a model in which L/D-double helix structures can be formed by natural Watson-Crick base pairs, but where the nucleosides of one of the two strands will occur in an anticlinal conformation. Interestingly enough, the duplexes (L-RNA/D-RNA and L-DNA/D-RNA in these models can show either right- or left-handedness. This is a very new

  14. A ribozyme transcribed by a ribozyme

    DEFF Research Database (Denmark)

    Bentin, Thomas

    2011-01-01

    Prominent current ideas on how life emerged on Earth include an RNA world hypothesis in which RNA performed informational as well as catalytic functions in the absence of both DNA and protein. Demonstration of a self-replicative system based on ribonucleic acid polymers as both information carriers...... and catalysts would lend support to such a scenario. A pivotal component of this system would be an RNA dependent RNA polymerase ribozyme capable of replicating its own RNA gene. Recent work from the Holliger group at the Laboratory for Molecular Biology in Cambridge has provided synthetic ribozymes1 that just...

  15. Lanthanide Cofactors for Triphosphorylation Ribozymes

    Science.gov (United States)

    Sweeney, K. J.; Müller, U. F.

    2017-07-01

    RNA world organisms could have used trimetaphosphate as energy source for thermodynamically unfavorable RNA polymerization. Using in vitro selection we show here that Lanthanides can serve as cofactors for ribozyme-catalyzed RNA triphosphorylation.

  16. Mercury levels in the Smooth Hammerhead Shark Sphyrna zygaena (Carcharhiniformes: Sphyrnidae from Northern Peru

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    Adriana Gonzalez-Pestana

    2017-12-01

    Full Text Available The smooth hammerhead shark Sphyrna zygaena (Linnaeus, 1758 is one of the elasmobranch species most used for human consumption in Peru. However, the level of mercury in hammerhead muscle tissue is unknown. This study assessed the level of mercury found in the muscle of hammerhead sharks and its relation with human health. Moreover, we evaluated the relationship between shark body size and mercury levels. We analyzed 27 muscle samples of neonates and juveniles captured in northern Peru. Mercury concentrations varied between 0.13 and 0.86 mg kg-1 wet weight. Moreover, we found a negative and significant relationship between shark body size and mercury levels. This study represents the first evaluation of mercury levels of sharks in Peru. Although the values found do not exceed levels recommended by the World Health Organization (< 1 mg kg-1, we recommend expanding this study to include other size classes of sharks as well as other marine resources used for human consumption.

  17. Advancing Polymerase Ribozymes Towards Self-Replication

    Science.gov (United States)

    Tjhung, K. F.; Joyce, G. F.

    2017-07-01

    Autocatalytic replication and evolution in vitro by (i) a cross-chiral RNA polymerase catalyzing polymerization of mononucleotides of the opposite handedness; (ii) non-covalent assembly of component fragments of an existing RNA polymerase ribozyme.

  18. Diet of scalloped hammerhead shark in eastern Gulf of Mexico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile scalloped hammerhead sharks, Sphyrna lewini, were collected in northwest Florida to examine foraging ecology, bioenergetics, and trophic level (30-60 cm FL...

  19. Chemical fidelity of an RNA polymerase ribozyme

    DEFF Research Database (Denmark)

    Attwater, J.; Tagami, S.; Kimoto, M.

    2013-01-01

    for function. Here we have explored the chemical fidelity, i.e. substrate selectivity and specificity for both single and multiple catalytic steps of the Z RNA polymerase ribozyme-a modern day analogue of the primordial RNA replicase. Using a wide range of nucleotide analogues and ionic conditions, we observe......The emergence of catalytically active RNA enzymes (ribozymes) is widely believed to have been an important transition in the origin of life. In the context of a likely heterogeneous chemical environment, substrate specificity and selectivity of these primordial enzymes would have been critical...

  20. Helium ion beam induced growth of hammerhead AFM probes

    NARCIS (Netherlands)

    Nanda, G.; Veldhoven, E. van; Maas, D.J.; Sadeghian Marnani, H.; Alkemade, P.F.A.

    2015-01-01

    The authors report the direct-write growth of hammerhead atomic force microscope (AFM) probes by He+ beam induced deposition of platinum-carbon. In order to grow a thin nanoneedle on top of a conventional AFM probe, the authors move a focused He+ beam during exposure to a PtC precursor gas. In the

  1. Molecular characterization of a new member of the lariat capping twin-ribozyme introns

    DEFF Research Database (Denmark)

    Tang, Yunjia; Nielsen, Henrik; Masquida, Benoît

    2014-01-01

    BACKGROUND: Twin-ribozyme introns represent a complex class of mobile group I introns that harbour a lariat capping (LC) ribozyme and a homing endonuclease gene embedded in a conventional self-splicing group I ribozyme (GIR2). Twin-ribozyme introns have so far been confined to nucleolar DNA in Na...

  2. A new RNA branching activity: the GIR1 ribozyme

    DEFF Research Database (Denmark)

    Nielsen, Henrik; Johansen, Steinar D

    2006-01-01

    The formation of lariat intermediates during the first step of splicing of group II introns and spliceosomal introns is a well-studied fundamental reaction in molecular biology. Apart from this prominent example, there are surprisingly few occurrences of branched nucleotides or even 2......',5'-phosphodiester bonds in biology. We recently described a new ribozyme, the GIR1 branching ribozyme, which catalyzes the formation of a tiny lariat that caps an mRNA. This new example together with work on artificial branching ribozymes and deoxyribozymes shows that branching is facile and points...... to the possibility that branching reactions could be more prevalent than previously recognized....

  3. Molecular modelling of the GIR1 branching ribozyme gives new insight into evolution of structurally related ribozymes

    DEFF Research Database (Denmark)

    Beckert, Bertrand Dominique; Nielsen, Henrik; Einvik, Christer

    2008-01-01

    a catalytic core showing a different topology from that of group I ribozymes. The differences include a core J8/7 region that has been reduced and is complemented by residues from the pre-lariat fold. These findings provide the basis for an evolutionary mechanism that accounts for the change from group I...... splicing ribozyme to the branching GIR1 architecture. Such an evolutionary mechanism can be applied to other large RNAs such as the ribonuclease P....

  4. Compaction of a Bacterial Group I Ribozyme Coincides with the Assembly of Core Helices

    International Nuclear Information System (INIS)

    Perez-Salas, U.; Rangan, P.; Krueger, S.; Briber, R.; Thirumalai, D.; Woodson, S.

    2004-01-01

    Counterions are critical to the self-assembly of RNA tertiary structure because they neutralize the large electrostatic forces which oppose the folding process. Changes in the size and shape of the Azoarcus group I ribozyme as a function of Mg 2+ and Na + concentration were followed by small angle neutron scattering. In low salt buffer, the RNA was expanded, with an average radius of gyration (R g ) of 53 ± 1 Angstroms. A highly cooperative transition to a compact form (R g = 31.5 ± 0.5 Angstroms) was observed between 1.6 and 1.7 mM MgCl 2 . The collapse transition, which is unusually sharp in Mg 2+ , has the characteristics of a first-order phase transition. Partial digestion with ribonuclease T1 under identical conditions showed that this transition correlated with the assembly of double helices in the ribozyme core. Fivefold higher Mg 2+ concentrations were required for self-splicing, indicating that compaction occurs before native tertiary interactions are fully stabilized. No further decrease in Rg was observed between 1.7 and 20 mM MgCl 2 , indicating that the intermediates have the same dimensions as the native ribozyme, within the uncertainty of the data (± 1 Angstroms). A more gradual transition to a final R g of approximately 33.5 Angstroms was observed between 0.45 and 2 M NaCl. This confirms the expectation that monovalent ions not only are less efficient in charge neutralization but also contract the RNA less efficiently than multivalent ions

  5. Kinetic partitioning mechanism of HDV ribozyme folding

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing, E-mail: wbzhang@whu.edu.cn [Department of Physics, Wuhan University, Wuhan, Hubei 430072 (China)

    2014-01-14

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  6. A natural fast-cleaving branching ribozyme from the amoeboflagellate Naegleria pringsheimi

    DEFF Research Database (Denmark)

    Tang, Yunjia; Nielsen, Henrik; Birgisdottir, Asa Birna

    2011-01-01

    The GIR1 branching ribozyme constitutes a separate class of naturally occurring ribozymes. Most studies have been performed with the single GIR1 known from the myxomycete Didymium iridis whereas the large number of GIR1s found in the amoeboflagellate Naegleria has remained largely uncharacterized....... Here, we investigate ribozyme cleavage properties of a collection of Naegleria GIR1 ribozymes and define the variant from N. pringsheimi as a suitable model due to its superior activity in vitro. We identify the minimal ribozyme by deletion analysis applying a new RNase R based assay for the branching...

  7. Structural studies on an internal loop from a hairpin ribozyme

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Z.; SantaLucia, J. Jr.; Tinoco, I. Jr. [Univ. of California, Berkeley, CA (United States)

    1994-12-01

    Ribozymes, RNA enzymes, catalyze site-specific RNA cleavage and ligation reactions. We are studying the three-dimensional structure of a hairpin ribozyme derived from the minus strand of tobacco ring spot virus satellite RNA ((-)sTRSV), which has been engineering to specifically cleave the HIV-1 RNA. The minimum structure for the catalytic reaction involves a 50-nucleotide ribozyme and a 14-nucleotide substrate. The proposed secondary structure of the ribozyme-substrate complex consists of four short helices separated by two internal loops. The relatively large size (64-nucleotide) of the ribozyme-substrate complex presents formidable problems in solving the structure using NMR. Therefore we are studying smaller structural subunits of the complex. We are determining the high resolution structure of the symmetric internal loop involving the cleavage site and the flanking helices. One strand of the internal loop was selectively {sup 13}C-labeled at C8 of each purine and C6 of each pyrimidine. By using {sup 13}C-edited two-dimensional NMR, the proton NOESY spectrum was greatly simplified. This allowed unambiguous sequential proton resonance assignments along each strand. Three-dimensional {sup 1}-{sup 13}C HMQC-NOESY was used to further facilitate resonance assignments. We are also enzymatically synthesizing the entire 50-nucleotide ribozyme and will combine it with the {sup 13}C-labeled substrate. Through comparison of the NOE connectivities of the labeled nucleotides from the internal loop alone with those from the entire complex, the differences between the two structures can be elucidated.

  8. Speciation of a group I intron into a lariat capping ribozyme

    DEFF Research Database (Denmark)

    Meyer, Mélanie; Nielsen, Henrik; Oliéric, Vincent

    2014-01-01

    The lariat-capping (LC) ribozyme is a natural ribozyme isolated from eukaryotic microorganisms. Despite apparent structural similarity to group I introns, the LC ribozyme catalyzes cleavage by a 2',5' branching reaction, leaving the 3' product with a 3-nt lariat cap that functionally substitutes ....... The structures also show how conserved interactions twist residues, forming the lariat to join chemical groups involved in branching....

  9. Many Activities, One Structure: Functional Plasticity of Ribozyme Folds

    Directory of Open Access Journals (Sweden)

    Matthew W.L. Lau

    2016-11-01

    Full Text Available Catalytic RNAs, or ribozymes, are involved in a number of essential biological processes, such as replication of RNA genomes and mobile genetic elements, RNA splicing, translation, and RNA degradation. The function of ribozymes requires the formation of active sites decorated with RNA functional groups within defined three-dimensional (3D structures. The genotype (sequence of RNAs ultimately determines what 3D structures they adopt (as a function of their environmental conditions. These 3D structures, in turn, give rise to biochemical activity, which can further elaborate them by catalytic rearrangements or association with other molecules. The fitness landscape of a non-periodic linear polymer, such as RNA, relates its primary structure to a phenotype. Two major challenges in the analysis of ribozymes is to map all possible genotypes to their corresponding catalytic activity (that is, to determine their fitness landscape experimentally, and to understand whether their genotypes and three-dimensional structures can support multiple different catalytic functions. Recently, the combined results of experiments that employ in vitro evolution methods, high-throughput sequencing and crystallographic structure determination have hinted at answers to these two questions: while the fitness landscape of ribozymes is rugged, meaning that their catalytic activity cannot be optimized by a smooth trajectory in sequence space, once an RNA achieves a stable three-dimensional fold, it can be endowed with distinctly different biochemical activities through small changes in genotype. This functional plasticity of highly structured RNAs may be particularly advantageous for the adaptation of organisms to drastic changes in selective pressure, or for the development of new biotechnological tools.

  10. Local neutral networks help maintain inaccurately replicating ribozymes.

    Science.gov (United States)

    Szilágyi, András; Kun, Ádám; Szathmáry, Eörs

    2014-01-01

    The error threshold of replication limits the selectively maintainable genome size against recurrent deleterious mutations for most fitness landscapes. In the context of RNA replication a distinction between the genotypic and the phenotypic error threshold has been made; where the latter concerns the maintenance of secondary structure rather than sequence. RNA secondary structure is treated as a proxy for function. The phenotypic error threshold allows higher per digit mutation rates than its genotypic counterpart, and is known to increase with the frequency of neutral mutations in sequence space. Here we show that the degree of neutrality, i.e. the frequency of nearest-neighbour (one-step) neutral mutants is a remarkably accurate proxy for the overall frequency of such mutants in an experimentally verifiable formula for the phenotypic error threshold; this we achieve by the full numerical solution for the concentration of all sequences in mutation-selection balance up to length 16. We reinforce our previous result that currently known ribozymes could be selectively maintained by the accuracy known from the best available polymerase ribozymes. Furthermore, we show that in silico stabilizing selection can increase the mutational robustness of ribozymes due to the fact that they were produced by artificial directional selection in the first place. Our finding offers a better understanding of the error threshold and provides further insight into the plausibility of an ancient RNA world.

  11. Prebiotic Factors Influencing the Activity of a Ligase Ribozyme

    Directory of Open Access Journals (Sweden)

    Fabrizio Anella

    2017-04-01

    Full Text Available An RNA-lipid origin of life scenario provides a plausible route for compartmentalized replication of an informational polymer and subsequent division of the container. However, a full narrative to form such RNA protocells implies that catalytic RNA molecules, called ribozymes, can operate in the presence of self-assembled vesicles composed of prebiotically relevant constituents, such as fatty acids. Hereby, we subjected a newly engineered truncated variant of the L1 ligase ribozyme, named tL1, to various environmental conditions that may have prevailed on the early Earth with the objective to find a set of control parameters enabling both tL1-catalyzed ligation and formation of stable myristoleic acid (MA vesicles. The separate and concurrent effects of temperature, concentrations of Mg2+, MA, polyethylene glycol and various solutes were investigated. The most favorable condition tested consists of 100 mM NaCl, 1 mM Mg2+, 5 mM MA, and 4 °C temperature, whereas the addition of Mg2+-chelating solutes, such as citrate, tRNAs, aspartic acid, and nucleoside triphosphates severely inhibits the reaction. These results further solidify the RNA-lipid world hypothesis and stress the importance of using a systems chemistry approach whereby a wide range of prebiotic factors interfacing with ribozymes are considered.

  12. Mapping the Chemical Space of the RNA Cleavage and Its Implications for Ribozyme Catalysis

    Czech Academy of Sciences Publication Activity Database

    Mlýnský, V.; Kührová, P.; Jurečka, P.; Šponer, Jiří; Otyepka, M.; Banáš, Pavel

    2017-01-01

    Roč. 121, č. 48 (2017), s. 10828-10840 ISSN 1520-6106 R&D Projects: GA ČR GAP208/12/1878 Institutional support: RVO:68081707 Keywords : delta-virus ribozyme * self-cleaving ribozymes Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.177, year: 2016

  13. Engineering integrated digital circuits with allosteric ribozymes for scaling up molecular computation and diagnostics.

    Science.gov (United States)

    Penchovsky, Robert

    2012-10-19

    Here we describe molecular implementations of integrated digital circuits, including a three-input AND logic gate, a two-input multiplexer, and 1-to-2 decoder using allosteric ribozymes. Furthermore, we demonstrate a multiplexer-decoder circuit. The ribozymes are designed to seek-and-destroy specific RNAs with a certain length by a fully computerized procedure. The algorithm can accurately predict one base substitution that alters the ribozyme's logic function. The ability to sense the length of RNA molecules enables single ribozymes to be used as platforms for multiple interactions. These ribozymes can work as integrated circuits with the functionality of up to five logic gates. The ribozyme design is universal since the allosteric and substrate domains can be altered to sense different RNAs. In addition, the ribozymes can specifically cleave RNA molecules with triplet-repeat expansions observed in genetic disorders such as oculopharyngeal muscular dystrophy. Therefore, the designer ribozymes can be employed for scaling up computing and diagnostic networks in the fields of molecular computing and diagnostics and RNA synthetic biology.

  14. Generation and Development of RNA Ligase Ribozymes with Modular Architecture Through “Design and Selection”

    Directory of Open Access Journals (Sweden)

    Yuki Fujita

    2010-08-01

    Full Text Available In vitro selection with long random RNA libraries has been used as a powerful method to generate novel functional RNAs, although it often requires laborious structural analysis of isolated RNA molecules. Rational RNA design is an attractive alternative to avoid this laborious step, but rational design of catalytic modules is still a challenging task. A hybrid strategy of in vitro selection and rational design has been proposed. With this strategy termed “design and selection,” new ribozymes can be generated through installation of catalytic modules onto RNA scaffolds with defined 3D structures. This approach, the concept of which was inspired by the modular architecture of naturally occurring ribozymes, allows prediction of the overall architectures of the resulting ribozymes, and the structural modularity of the resulting ribozymes allows modification of their structures and functions. In this review, we summarize the design, generation, properties, and engineering of four classes of ligase ribozyme generated by design and selection.

  15. Crossing lines: a multidisciplinary framework for assessing connectivity of hammerhead sharks across jurisdictional boundaries.

    Science.gov (United States)

    Chin, A; Simpfendorfer, C A; White, W T; Johnson, G J; McAuley, R B; Heupel, M R

    2017-04-21

    Conservation and management of migratory species can be complex and challenging. International agreements such as the Convention on Migratory Species (CMS) provide policy frameworks, but assessments and management can be hampered by lack of data and tractable mechanisms to integrate disparate datasets. An assessment of scalloped (Sphyrna lewini) and great (Sphyrna mokarran) hammerhead population structure and connectivity across northern Australia, Indonesia and Papua New Guinea (PNG) was conducted to inform management responses to CMS and Convention on International Trade in Endangered Species listings of these species. An Integrated Assessment Framework (IAF) was devised to systematically incorporate data across jurisdictions and create a regional synopsis, and amalgamated a suite of data from the Australasian region. Scalloped hammerhead populations are segregated by sex and size, with Australian populations dominated by juveniles and small adult males, while Indonesian and PNG populations included large adult females. The IAF process introduced genetic and tagging data to produce conceptual models of stock structure and movement. Several hypotheses were produced to explain stock structure and movement patterns, but more data are needed to identify the most likely hypothesis. This study demonstrates a process for assessing migratory species connectivity and highlights priority areas for hammerhead management and research.

  16. Crossing lines: a multidisciplinary framework for assessing connectivity of hammerhead sharks across jurisdictional boundaries

    Science.gov (United States)

    Chin, A.; Simpfendorfer, C. A.; White, W. T.; Johnson, G. J.; McAuley, R. B.; Heupel, M. R.

    2017-04-01

    Conservation and management of migratory species can be complex and challenging. International agreements such as the Convention on Migratory Species (CMS) provide policy frameworks, but assessments and management can be hampered by lack of data and tractable mechanisms to integrate disparate datasets. An assessment of scalloped (Sphyrna lewini) and great (Sphyrna mokarran) hammerhead population structure and connectivity across northern Australia, Indonesia and Papua New Guinea (PNG) was conducted to inform management responses to CMS and Convention on International Trade in Endangered Species listings of these species. An Integrated Assessment Framework (IAF) was devised to systematically incorporate data across jurisdictions and create a regional synopsis, and amalgamated a suite of data from the Australasian region. Scalloped hammerhead populations are segregated by sex and size, with Australian populations dominated by juveniles and small adult males, while Indonesian and PNG populations included large adult females. The IAF process introduced genetic and tagging data to produce conceptual models of stock structure and movement. Several hypotheses were produced to explain stock structure and movement patterns, but more data are needed to identify the most likely hypothesis. This study demonstrates a process for assessing migratory species connectivity and highlights priority areas for hammerhead management and research.

  17. Pressure modulates the self-cleavage step of the hairpin ribozyme

    Science.gov (United States)

    Schuabb, Caroline; Kumar, Narendra; Pataraia, Salome; Marx, Dominik; Winter, Roland

    2017-03-01

    The ability of certain RNAs, denoted as ribozymes, to not only store genetic information but also catalyse chemical reactions gave support to the RNA world hypothesis as a putative step in the development of early life on Earth. This, however, might have evolved under extreme environmental conditions, including the deep sea with pressures in the kbar regime. Here we study pressure-induced effects on the self-cleavage of hairpin ribozyme by following structural changes in real-time. Our results suggest that compression of the ribozyme leads to an accelerated transesterification reaction, being the self-cleavage step, although the overall process is retarded in the high-pressure regime. The results reveal that favourable interactions between the reaction site and neighbouring nucleobases are strengthened under pressure, resulting therefore in an accelerated self-cleavage step upon compression. These results suggest that properly engineered ribozymes may also act as piezophilic biocatalysts in addition to their hitherto known properties.

  18. A four-way junction accelerates hairpin ribozyme folding via a discrete intermediate

    Science.gov (United States)

    Tan, Elliot; Wilson, Timothy J.; Nahas, Michelle K.; Clegg, Robert M.; Lilley, David M. J.; Ha, Taekjip

    2003-01-01

    The natural form of the hairpin ribozyme comprises two major structural elements: a four-way RNA junction and two internal loops carried by adjacent arms of the junction. The ribozyme folds into its active conformation by an intimate association between the loops, and the efficiency of this process is greatly enhanced by the presence of the junction. We have used single-molecule spectroscopy to show that the natural form fluctuates among three distinct states: the folded state and two additional, rapidly interconverting states (proximal and distal) that are inherited from the junction. The proximal state juxtaposes the two loop elements, thereby increasing the probability of their interaction and thus accelerating folding by nearly three orders of magnitude and allowing the ribozyme to fold rapidly in physiological conditions. Therefore, the hairpin ribozyme exploits the dynamics of the junction to facilitate the formation of the active site from its other elements. Dynamic interplay between structural elements, as we demonstrate for the hairpin ribozyme, may be a general theme for other functional RNA molecules. PMID:12883002

  19. Great hammerhead sharks swim on their side to reduce transport costs.

    Science.gov (United States)

    Payne, Nicholas L; Iosilevskii, Gil; Barnett, Adam; Fischer, Chris; Graham, Rachel T; Gleiss, Adrian C; Watanabe, Yuuki Y

    2016-07-26

    Animals exhibit various physiological and behavioural strategies for minimizing travel costs. Fins of aquatic animals play key roles in efficient travel and, for sharks, the functions of dorsal and pectoral fins are considered well divided: the former assists propulsion and generates lateral hydrodynamic forces during turns and the latter generates vertical forces that offset sharks' negative buoyancy. Here we show that great hammerhead sharks drastically reconfigure the function of these structures, using an exaggerated dorsal fin to generate lift by swimming rolled on their side. Tagged wild sharks spend up to 90% of time swimming at roll angles between 50° and 75°, and hydrodynamic modelling shows that doing so reduces drag-and in turn, the cost of transport-by around 10% compared with traditional upright swimming. Employment of such a strongly selected feature for such a unique purpose raises interesting questions about evolutionary pathways to hydrodynamic adaptations, and our perception of form and function.

  20. Complete mitochondrial genome of the scalloped hammerhead Sphyrna lewini (Carcharhiniformes: Sphyrnidae).

    Science.gov (United States)

    Chen, Xiao; Xiang, Dan; Xu, Yuziwei; Shi, Xiaofang

    2015-08-01

    The complete mitochondrial genome of the endangered scalloped hammerhead Sphyrna lewini was firstly determined in this study. It is 16,726 bp in length with the typical gene composition and orders in vertebrates. The overall base composition is 31.4% A, 26.3% C, 13.2% G and 29.1% T. Two start codon (ATG and GTG) and three stop codon (TAG, AGA and TAA/TA/T) patterns were found in protein-coding genes. Except for the tRNA-Ser2, the remaining 21 tRNAs can be folded into the typical cloverleaf structure. The control region possess the highest A + T content (66.1%) and lowest G content (12.6%) among all mitochondrial partitions.

  1. The glmS ribozyme cofactor is a general acid-base catalyst.

    Science.gov (United States)

    Viladoms, Júlia; Fedor, Martha J

    2012-11-21

    The glmS ribozyme is the first natural self-cleaving ribozyme known to require a cofactor. The d-glucosamine-6-phosphate (GlcN6P) cofactor has been proposed to serve as a general acid, but its role in the catalytic mechanism has not been established conclusively. We surveyed GlcN6P-like molecules for their ability to support self-cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of the cofactors. For cofactors with low binding affinities, the contribution to rate enhancement was proportional to their intrinsic acidity. This linear free-energy relationship between cofactor efficiency and acid dissociation constants is consistent with a mechanism in which the cofactors participate directly in the reaction as general acid-base catalysts. A high value for the Brønsted coefficient (β ~ 0.7) indicates that a significant amount of proton transfer has already occurred in the transition state. The glmS ribozyme is the first self-cleaving RNA to use an exogenous acid-base catalyst.

  2. Ribozyme Activity of RNA Nonenzymatically Polymerized from 3 ',5 '-Cyclic GMP

    Czech Academy of Sciences Publication Activity Database

    Pino, S.; Costanzo, G.; Giorgi, A.; Šponer, Jiří; Šponer, Judit E.; Di Mauro, E.

    2013-01-01

    Roč. 15, č. 12 (2013), s. 5362-5383 ISSN 1099-4300 R&D Projects: GA ČR(CZ) GAP208/10/2302; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081707 Keywords : RNA polymerization * RNA origin * ribozymes Subject RIV: BO - Biophysics Impact factor: 1.564, year: 2013

  3. Wobble pairs of the HDV ribozyme play specific roles in stabilization of active site dynamics

    Czech Academy of Sciences Publication Activity Database

    Sripathi, K.N.; Banáš, P.; Réblová, K.; Šponer, Jiří; Otyepka, M.; Walter, Nils G.

    2015-01-01

    Roč. 17, č. 8 (2015), s. 5887-5900 ISSN 1463-9076 R&D Projects: GA ČR GAP208/12/1878 Institutional support: RVO:68081707 Keywords : HEPATITIS -DELTA-VIRUS * SELF-CLEAVING RIBOZYMES * ACID-BASE CATALYSIS Subject RIV: BO - Biophysics Impact factor: 4.449, year: 2015

  4. A novel strategy for selection of allosteric ribozymes yields RiboReporter™ sensors for caffeine and aspartame

    Science.gov (United States)

    Ferguson, Alicia; Boomer, Ryan M.; Kurz, Markus; Keene, Sara C.; Diener, John L.; Keefe, Anthony D.; Wilson, Charles; Cload, Sharon T.

    2004-01-01

    We have utilized in vitro selection technology to develop allosteric ribozyme sensors that are specific for the small molecule analytes caffeine or aspartame. Caffeine- or aspartame-responsive ribozymes were converted into fluorescence-based RiboReporter™ sensor systems that were able to detect caffeine or aspartame in solution over a concentration range from 0.5 to 5 mM. With read-times as short as 5 min, these caffeine- or aspartame-dependent ribozymes function as highly specific and facile molecular sensors. Interestingly, successful isolation of allosteric ribozymes for the analytes described here was enabled by a novel selection strategy that incorporated elements of both modular design and activity-based selection methods typically used for generation of catalytic nucleic acids. PMID:15026535

  5. Characterization of cis-Acting RNA Elements of Zika Virus by Using a Self-Splicing Ribozyme-Dependent Infectious Clone.

    Science.gov (United States)

    Liu, Zhong-Yu; Yu, Jiu-Yang; Huang, Xing-Yao; Fan, Hang; Li, Xiao-Feng; Deng, Yong-Qiang; Ji, Xue; Cheng, Meng-Li; Ye, Qing; Zhao, Hui; Han, Jian-Feng; An, Xiao-Ping; Jiang, Tao; Zhang, Bo; Tong, Yi-Gang; Qin, Cheng-Feng

    2017-11-01

    Zika virus (ZIKV) has caused significant outbreaks and epidemics in the Americas recently, raising global concern due to its ability to cause microcephaly and other neurological complications. A stable and efficient infectious clone of ZIKV is urgently needed. However, the instability and toxicity of flavivirus cDNA clones in Escherichia coli hosts has hindered the development of ZIKV infectious clones. Here, using a novel self-splicing ribozyme-based strategy, we generated a stable infectious cDNA clone of a contemporary ZIKV strain imported from Venezuela to China in 2016. The constructed clone contained a modified version of the group II self-splicing intron P.li.LSUI2 near the junction between the E and NS1 genes, which were removed from the RNA transcripts by an easy-to-establish in vitro splicing reaction. Transfection of the spliced RNAs into BHK-21 cells led to the production of infectious progeny virus that resembled the parental virus. Finally, potential cis -acting RNA elements in ZIKV genomic RNA were identified based on this novel reverse genetics system, and the critical role of 5'-SLA promoter and 5'-3' cyclization sequences were characterized by a combination of different assays. Our results provide another stable and reliable reverse genetics system for ZIKV that will help study ZIKV infection and pathogenesis, and the novel self-splicing intron-based strategy could be further expanded for the construction of infectious clones from other emerging and reemerging flaviviruses. IMPORTANCE The ongoing Zika virus (ZIKV) outbreaks have drawn global concern due to the unexpected causal link to fetus microcephaly and other severe neurological complications. The infectious cDNA clones of ZIKV are critical for the research community to study the virus, understand the disease, and inform vaccine design and antiviral screening. A panel of existing technologies have been utilized to develop ZIKV infectious clones. Here, we successfully generated a stable

  6. Effects of fasting and refeeding on intestinal cell proliferation and apoptosis in hammerhead shark (Sphyrna lewini

    Directory of Open Access Journals (Sweden)

    Hideya Takahashi

    2014-04-01

    Full Text Available Objective: To examine the effects of fasting and refeeding on intestinal cell proliferation and apoptosis in an opportunistic predator, hammerhead shark (Sphyrna lewini of elasmobranch fishes which are among the earliest known extant groups of vertebrates to have the valvular intestine typical for the primitive species. Methods: Animals were euthanized after 5-10 d of fasting or feeding, or after 10-day fasting and 5-day refeeding. Intestinal apoptosis and cell proliferation were assessed by using oligonucleotide detection assay, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and immunohistochemistry of proliferating cells nuclear antigen. Results: Plasma levels of cholesterol and glucose were reduced by fasting. Intestinal apoptosis generally decreased during fasting. Numerous apoptotic cells were observed around the tips of the villi, primarily in the epithelium in the fed sharks, whereas fewer labeled nuclei were detected in the epithelium of fasted sharks. Refeeding returned intestinal apoptosis to the level in the fed sharks. Proliferating cells were observed in the epithelium around the troughs of the villi and greater in number in fed sharks, whereas fewer labeled nuclei were detected in fasted sharks. Conclusions: The cell turnover is modified in both intestinal epithelia of the shark and the murines by fasting/feeding, but in opposite directions. The difference may reflect the feeding ecology of the elasmobranchs, primitive intermittent feeders.

  7. Expanding subjectivities

    DEFF Research Database (Denmark)

    Lundgaard Andersen, Linda; Soldz, Stephen

    2012-01-01

    A major theme in recent psychoanalytic thinking concerns the use of therapist subjectivity, especially “countertransference,” in understanding patients. This thinking converges with and expands developments in qualitative research regarding the use of researcher subjectivity as a tool......-Saxon and continental traditions, this special issue provides examples of the use of researcher subjectivity, informed by psychoanalytic thinking, in expanding research understanding....

  8. Disparate HDV ribozyme crystal structures represent intermediates on a rugged free-energy landscape

    Czech Academy of Sciences Publication Activity Database

    Sripathi, K.N.; Tay, W.W.; Banáš, P.; Otyepka, M.; Šponer, Jiří; Walter, N. G.

    2014-01-01

    Roč. 20, č. 7 (2014), s. 1112-1128 ISSN 1355-8382 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR(CZ) GAP208/12/1878 Institutional support: RVO:68081707 Keywords : time-resolved FRET * steady-state FRET * small ribozyme Subject RIV: BO - Biophysics Impact factor: 4.936, year: 2014

  9. Thermodynamics and kinetics of RNA tertiary structure formation in the junctionless hairpin ribozyme.

    Science.gov (United States)

    White, Neil A; Hoogstraten, Charles G

    2017-09-01

    The hairpin ribozyme consists of two RNA internal loops that interact to form the catalytically active structure. This docking transition is a rare example of intermolecular formation of RNA tertiary structure without coupling to helix annealing. We have used temperature-dependent surface plasmon resonance (SPR) to characterize the thermodynamics and kinetics of RNA tertiary structure formation for the junctionless form of the ribozyme, in which loops A and B reside on separate molecules. We find docking to be strongly enthalpy-driven and to be accompanied by substantial activation barriers for association and dissociation, consistent with the structural reorganization of both internal loops upon complex formation. Comparisons with the parallel analysis of a ribozyme variant carrying a 2'-O-methyl modification at the self-cleavage site and with published data in other systems reveal a surprising diversity of thermodynamic signatures, emphasizing the delicate balance of contributions to the free energy of formation of RNA tertiary structure. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Demographic processes underlying subtle patterns of population structure in the scalloped hammerhead shark, Sphyrna lewini.

    Directory of Open Access Journals (Sweden)

    Holly A Nance

    Full Text Available Genetic diversity (θ, effective population size (N(e, and contemporary levels of gene flow are important parameters to estimate for species of conservation concern, such as the globally endangered scalloped hammerhead shark, Sphyrna lewini. Therefore, we have reconstructed the demographic history of S. lewini across its Eastern Pacific (EP range by applying classical and coalescent population genetic methods to a combination of 15 microsatellite loci and mtDNA control region sequences. In addition to significant population genetic structure and isolation-by-distance among seven coastal sites between central Mexico and Ecuador, the analyses revealed that all populations have experienced a bottleneck and that all current values of θ are at least an order of magnitude smaller than ancestral θ, indicating large decreases in N(e (θ = 4N(eμ, where μ is the mutation rate. Application of the isolation-with-migration (IM model showed modest but significant genetic connectivity between most sampled sites (point estimates of Nm = 0.1-16.7, with divergence times (t among all populations significantly greater than zero. Using a conservative (i.e., slow fossil-based taxon-specific phylogenetic calibration for mtDNA mutation rates, posterior probability distributions (PPDs for the onset of the decline in N(e predate modern fishing in this region. The cause of decline over the last several thousand years is unknown but is highly atypical as a post-glacial demographic history. Regardless of the cause, our data and analyses suggest that S. lewini was far more abundant throughout the EP in the past than at present.

  11. An anti-VEGF ribozyme embedded within the adenoviral VAI sequence inhibits glioblastoma cell angiogenic potential in vitro.

    Science.gov (United States)

    Ciafrè, Silvia Anna; Niola, Francesco; Wannenes, Francesca; Farace, Maria Giulia

    2004-01-01

    Vascular endothelial growth factor (VEGF) plays an important role in tumor angiogenesis, where it functions as one of the major angiogenic factors sustaining growth and draining catabolites. In this study, we developed an anti-VEGF ribozyme targeted to the 5' part of human VEGF mRNA. We endowed this ribozyme with an additional feature expected to improve its activity in vivo, by cloning it into a VAI transcriptional cassette. VAI is originally part of the adenovirus genome, and is characterized by high transcription rates, good stability due to its strong secondary structure and cytoplasmic localization. Transfection of U87 human glioblastoma cells with plasmid vectors encoding for this ribozyme resulted in a strong (-56%) reduction of VEGF secreted in the extracellular medium, indicating a good biological activity of the ribozyme. Moreover, this reduction in VEGF secretion had the important functional consequence of drastically diminishing the formation of tube-like structures of human umbilical vascular endothelial cells in a Matrigel in vitro angiogenesis assay. In conclusion, our VAI-embedded anti-VEGF ribozyme is a good inhibitor of angiogenesis in vitro, in a glioblastoma cell context. Thus, it may represent a useful tool for future applications in vivo, for antiangiogenic gene therapy of glioblastoma and of highly vascularized tumors. Copyright 2004 S. Karger AG, Basel

  12. DiGIR1 and NaGIR1: naturally occurring group I-like ribozymes with unique core organization and evolved biological role

    DEFF Research Database (Denmark)

    Johansen, Steinar; Einvik, Christer; Nielsen, Henrik

    2002-01-01

    introns (twin-ribozyme introns) in distantly related organisms. The Didymium GIR1 (DiGIR1) and Naegleria GIR1 (NaGIR1) share fundamental features in structural organization and reactivity, and display significant differences when compared to the related group I splicing ribozymes. GIR1 lacks...

  13. SOME BIOLOGICAL ASPECTS OF SCALLOPED HAMMERHEAD SHARKS (Sphyrna lewini Griffith & Smith, 1834 CAUGHT FROM COASTAL FISHERIES IN THE EASTERN INDIAN OCEAN

    Directory of Open Access Journals (Sweden)

    Umi Chodrijah

    2015-12-01

    Full Text Available Indonesia has the largest chondrichthyan fishery in the world, with a reported of 105,000 and 118,000 tonnes landed in 2002 and 2003 respectively. Scalloped hammerhead shark was either targeted or by-catch from this fishery, mostly for its fins. Despite of the growing concern around the world, the availability of biological data of this species, especially in the Eastern Indian Ocean is still lacking. The objectives of this paper are to present some biological information (size composition and sex ratio of the scalloped hammerhead, from coastal fisheries in Eastern Indian Ocean. The data used for the analysis comprised of two components, i.e. survey data in 2010 (February, March, June, August, October and December and data from daily monitoring shark landing in 2013 (January to December. Substantially lower mean size, more immature sharks and more frequent of female caught over years showed that scalloped hammerhead shark in the Eastern Indian Ocean are facing intensive fishing pressure which could lead to overfishing. This could harm the sustainability of scalloped hammerhead shark resource in the long run. The relationship between clasper length and total length was positively correlated where every 5 cmTL increment on clasper length adding 51 cmTL on total length.

  14. Expandable stents.

    Science.gov (United States)

    Nesbitt, J C; Carrasco, H

    1996-05-01

    Expandable metallic stents are effective in selected patients with malignant or benign airway stenoses. When used for malignant lesions, the primary purpose of the stent is to improve the quality of life; stents are usually chosen for palliation of symptoms in recognition of the low likelihood of success for other therapy. For patients with benign stenoses, the stents provide a permanent source of structural support to alleviate the narrowed segment. The advantages of the expandable metallic stents are as follows: (1) they can be inserted through an endotracheal tube or under local anesthesia with relative simplicity under fluoroscopic guidance; (2) they do not impair the drainage of sputum because ciliary movement is not interrupted; (3) over a period of a few weeks, the meshwork is gradually covered with mucosa as the stent becomes incorporated into the airway wall; (4) ventilation usually is not impaired if the metallic mesh stent covers another nonstenosed bronchus, because the interstices of the stent are nonobstructive; and (5) they are dynamic and continue to expand over time, particularly if concurrent treatment achieves an effect on the lesion that caused stenosis. Disadvantages of the expandable stent include (1) they often are only temporarily effective for tracheobronchial stenosis due to intraluminal tumor or granulation tissue, both of which can grow between the wires; (2) they are considered permanent stents because removal is difficult; and (3) they can be poorly positioned during placement or can become displaced by progressive migration after placement, and they cannot be repositioned. A relative contraindication to insertion is an inflammatory process or infection that can predispose to granulation formation, particularly at the points of maximal contact pressure of the stent to the airway mucosa. In the presence of inflammation, it may be better to use a silicone prosthesis until the inflammatory process subsides and fibrosis occurs. Granulation

  15. Ribozyme Mediated gRNA Generation for In Vitro and In Vivo CRISPR/Cas9 Mutagenesis.

    Science.gov (United States)

    Lee, Raymond Teck Ho; Ng, Ashley Shu Mei; Ingham, Philip W

    2016-01-01

    CRISPR/Cas9 is now regularly used for targeted mutagenesis in a wide variety of systems. Here we report the use of ribozymes for the generation of gRNAs both in vitro and in zebrafish embryos. We show that incorporation of ribozymes increases the types of promoters and number of target sites available for mutagenesis without compromising mutagenesis efficiency. We have tested this by comparing the efficiency of mutagenesis of gRNA constructs with and without ribozymes and also generated a transgenic zebrafish expressing gRNA using a heat shock promoter (RNA polymerase II-dependent promoter) that was able to induce mutagenesis of its target. Our method provides a streamlined approach to test gRNA efficiency as well as increasing the versatility of conditional gene knock out in zebrafish.

  16. Group I-like ribozymes with a novel core organization perform obligate sequential hydrolytic cleavages at two processing sites

    DEFF Research Database (Denmark)

    Einvik, C; Nielsen, Henrik; Westhof, E

    1998-01-01

    A new category of self-splicing group I introns with conserved structural organization and function is found among the eukaryotic microorganisms Didymium and Naegleria. These complex rDNA introns contain two distinct ribozymes with different functions: a regular group I splicing...... available GIR1 sequences and propose a common RNA secondary structure resembling that of group I splicing-ribozymes, but with some important differences. The GIR1s lack most peripheral sequence components, as well as a P1 segment, and, at approximately 160-190 nt, they are the smallest functional group I...... ribozymes known from nature. All GIR1s were found to contain a novel 6-bp pseudoknot (P15) within their catalytic core region. Experimental support of the proposed structure was obtained from the Didymium GIR1 by RNA structure probing and site-directed mutagenesis. Three-dimensional modeling indicates...

  17. Expander Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 1. Expander Codes - The Sipser–Spielman Construction. Priti Shankar. General Article Volume 10 ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science Bangalore 560 012, India.

  18. Competition Between Co(NH3)63+ and Inner Sphere Mg2+ Ions in the HDV Ribozyme

    OpenAIRE

    Gong, Bo; Chen, Jui-Hui; Bevilacqua, Philip C.; Golden, Barbara L.; Carey, Paul R.

    2009-01-01

    Divalent cations play critical structural and functional roles in many RNAs. While the hepatitis delta virus (HDV) ribozyme can undergo self-cleavage in the presence of molar concentrations of monovalent cations, divalent cations such as Mg2+ are required for efficient catalysis under physiological conditions. Moreover, the cleavage reaction can be inhibited with Co(NH3)63+, an analog of Mg(H2O)62+. Here, the binding of Mg2+ and Co(NH3)63+ to the HDV ribozyme are studied by Raman microscopic ...

  19. A Comparison of the foraging ecology and bioenergetics of the early life-stages of two sympatric hammerhead sharks from 1998-07-12 to 2005-07-27 (NCEI Accession 0163192)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Archival Information Package (AIP) contains basic biological information on bonnethead and scalloped hammerhead sharks with specific (by stomach and prey item)...

  20. The life histories of endangered hammerhead sharks (Carcharhiniformes, Sphyrnidae) from the east coast of Australia.

    Science.gov (United States)

    Harry, A V; Macbeth, W G; Gutteridge, A N; Simpfendorfer, C A

    2011-06-01

    The life histories of two globally endangered hammerhead sharks, Sphyrna lewini and Sphyrna mokarran, were examined using samples collected from a range of commercial fisheries operating along the east coast of Australia. The catch of S. lewini was heavily biased towards males, and there were significant differences in von Bertalanffy growth parameters (L(∞) and k) and maturity [stretched total length (L(ST)) and age (A) at which 50% are mature, L(ST50) and A(50)] between those caught in the tropics (L(∞) = 2119 mm, k = 0·163, L(ST50) = 1471 mm, A(50) = 5·7 years) and those caught in temperate waters (L(∞) = 3199 mm, k = 0·093, L(ST50) = 2043 mm, A(50) = 8·9 years). The best-fit estimates for a three-parameter von Bertalanffy growth curve fit to both sexes were L(∞) = 3312 mm, L(0) = 584 mm and k = 0·076. Males attained a maximum age of 21 years and grew to at least 2898 mm L(ST). The longevity, maximum length and maturity of females could not be estimated as mature animals could not be sourced from any fishery. Length at birth inferred from neonates with open umbilical scars was 465-563 mm L(ST). There was no significant difference in length and age at maturity of male and female S. mokarran, which reached 50% maturity at 2279 mm L(ST) and 8·3 years. Sphyrna mokarran grew at a similar rate to S. lewini and the best-fit estimates for a two-parameter von Bertalanffy equation fit to length-at-age data for sexes combined with an assumed mean length-at-birth of 700 mm were L(∞) = 4027 mm and k = 0·079. Females attained a maximum age of 39·1 years and grew to at least 4391 mm L(ST). The oldest male S. mokarran was 31·7 years old and 3691 mm L(ST). Validation of annual growth-band deposition in S. mokarran was achieved through a mark, tag and recapture study. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  1. Extensive use of mesopelagic waters by a Scalloped hammerhead shark (Sphyrna lewini) in the Red Sea

    KAUST Repository

    Spaet, Julia L.Y.

    2017-09-06

    Background Despite being frequently landed in fish markets along the Saudi Arabian Red Sea coast, information regarding fundamental biology of the Scalloped hammerhead shark (Sphyrna lewini) in this region is scarce. Satellite telemetry studies can generate important data on life history, describe critical habitats, and ultimately redefine management strategies for sharks. To better understand the horizontal and vertical habitat use of S. lewini in the Red Sea and to aid with potential future development of zoning and management plans for key habitats, we deployed a pop-up satellite archival transmitting tag to track a single female specimen (240 cm total length) for a tracking period of 182 days. Results The tag was physically recovered after a deployment period of 6 months, thus providing the complete archived dataset of more than one million depth and temperature records. Based on a reconstructed, most probable track, the shark travelled a circular distance of approximately 1000 km from the central Saudi Arabian Red Sea southeastward into Sudanese waters, returning to the tagging location toward the end of the tracking period. Mesopelagic excursions to depths between 650 and 971 m occurred on 174 of the 182 days of the tracking period. Intervals between such excursions were characterized by constant oscillatory diving in the upper 100 m of the water column. Conclusions This study provides evidence that mesopelagic habitats might be more commonly used by S. lewini than previously suggested. We identified deep diving behavior throughout the 24-h cycle over the entire 6-month tracking period. In addition to expected nightly vertical habitat use, the shark exhibited frequent mesopelagic excursions during daytime. Deep diving throughout the diel cycle has not been reported before and, while dive functionality remains unconfirmed, our study suggests that mesopelagic excursions may represent foraging events within and below deep scattering layers. Additional research

  2. Evaluation of a Petition Requesting National Marine Fisheries Service (NMFS) to List the Smooth Hammerhead Shark (Sphryna zygaena) as a Threatened or Endangered Species Under the Endangered Species Act (ESA)

    Science.gov (United States)

    Sturm, A. B.

    2016-12-01

    The wildlife conservation organization, Defenders of Wildlife, petitioned NMFS to list the smooth hammerhead shark, Sphryna zygaena, as endangered or threatened throughout its range under the ESA. The petition was critically evaluated to determine if the petitioners presented substantial scientific or commercial information indicating that the smooth hammerhead shark may warrant listing under the ESA. The petition and the cited scientific literature (as well as scientific literature readily available in NMFS files) were evaluated to determine if the smooth hammerhead shark may be threatened or endangered because of any one or a combination of the following five ESA section 4(a)(1) factors: (1) present or threatened destruction, modification, or curtailment of its habitat or range; (2) over utilization for commercial, recreational, scientific, or educational purposes; (3) disease or predation; (4) inadequacy of existing regulatory mechanisms; (5) or other natural or manmade factors affecting its continued existence. The available scientific literature indicates that the smooth hammerhead shark populations have declined in multiple regions. Smooth hammerhead sharks may warrant listing due to ongoing threats of over utilization for commercial purposes by global fisheries that target and retain incidental catch of these species to obtain their high-value fins, possible inadequacies in global regulatory mechanisms to control this level of exploitation, and natural factors (such as inherent biological vulnerabilities) that may be exacerbating these threats. Based on these findings, the smooth hammerhead shark may warrant listing as a threatened or endangered species under the ESA and a status review of the species is currently being conducted.

  3. Partition expanders

    Czech Academy of Sciences Publication Activity Database

    Gavinsky, Dmitry; Pudlák, Pavel

    2017-01-01

    Roč. 60, č. 3 (2017), s. 378-395 ISSN 1432-4350 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : expanders * pseudorandomness * communication complexity Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.645, year: 2016 http://link.springer.com/article/10.1007%2Fs00224-016-9738-5

  4. Stereospecificity of oligonucleotide interactions revisited: no evidence for heterochiral hybridization and ribozyme/DNAzyme activity.

    Directory of Open Access Journals (Sweden)

    Kai Hoehlig

    Full Text Available A major challenge for the application of RNA- or DNA-oligonucleotides in biotechnology and molecular medicine is their susceptibility to abundant nucleases. One intriguing possibility to tackle this problem is the use of mirror-image (l-oligonucleotides. For aptamers, this concept has successfully been applied to even develop therapeutic agents, so-called Spiegelmers. However, for technologies depending on RNA/RNA or RNA/DNA hybridization, like antisense or RNA interference, it has not been possible to use mirror-image oligonucleotides because Watson-Crick base pairing of complementary strands is (thought to be stereospecific. Many scientists consider this a general principle if not a dogma. A recent publication proposing heterochiral Watson-Crick base pairing and sequence-specific hydrolysis of natural RNA by mirror-image ribozymes or DNAzymes (and vice versa prompted us to systematically revisit the stereospecificity of oligonucleotides hybridization and catalytic activity. Using hyperchromicity measurements we demonstrate that hybridization only occurs among homochiral anti-parallel complementary oligonucleotide strands. As expected, achiral PNA hybridizes to RNA and DNA irrespective of their chirality. In functional assays we could not confirm an alleged heterochiral hydrolytic activity of ribozymes or DNAzymes. Our results confirm a strict stereospecificity of oligonucleotide hybridization and clearly argue against the possibility to use mirror-image oligonucleotides for gene silencing or antisense applications.

  5. Contributions to the tooth morphology in early embryos of three species of hammerhead sharks (Elasmobranchii: Sphyrnidae) and their evolutionary implications.

    Science.gov (United States)

    Mello, Waldiney; Brito, Paulo Marques Machado

    2013-09-01

    The tooth types in the embryos of the hammerhead sharks Sphyrna tiburo, Sphyrna tudes and Eusphyra blochii are here described in labial and lingual views, and, in some cases, in additional views. The presence of cusplets was observed in the anterior teeth of S. tiburo and S. tudes, which is secondarily lost after early embryonic stages. Many aligned root foramina were detected in the sphyrnids, which, as the cusplets, are shared by many phylogenetic-related carcharhinids. Other anatomic features, related to the root and central cusp, are presented for the first time. Such characters represent the first step to compare the teeth of extant and fossil species. Copyright © 2013. Published by Elsevier SAS.

  6. The influence of junction conformation on RNA cleavage by the hairpin ribozyme in its natural junction form.

    Science.gov (United States)

    Thomson, J B; Lilley, D M

    1999-01-01

    In the natural form of the hairpin ribozyme the two loop-carrying duplexes that comprise the majority of essential bases for activity form two adjacent helical arms of a four-way RNA junction. In the present work we have manipulated the sequence around the junction in a way known to perturb the global folding properties. We find that replacement of the junction by a different sequence that has the same conformational properties as the natural sequence gives closely similar reaction rate and Arrhenius activation energy for the substrate cleavage reaction. By comparison, rotation of the natural sequence in order to alter the three-dimensional folding of the ribozyme leads to a tenfold reduction in the kinetics of cleavage. Replacement with the U1 four-way junction that is resistant to rotation into the antiparallel structure required to allow interaction between the loops also gives a tenfold reduction in cleavage rate. The results indicate that the conformation of the junction has a major influence on the catalytic activity of the ribozyme. The results are all consistent with a role for the junction in the provision of a framework by which the loops are presented for interaction in order to create the active form of the ribozyme. PMID:10024170

  7. Purification, characterization, and biological activity of insulins from the spotted dogfish, Scyliorhinus canicula, and the hammerhead shark, Sphyrna lewini.

    Science.gov (United States)

    Anderson, W Gary; Ali, Mohamed F; Einarsdóttir, Ingibjörg E; Schäffer, Lauge; Hazon, Neil; Conlon, J Michael

    2002-03-01

    Insulin was purified from pancreatic extracts of two elasmobranch species belonging to different families in the order Carcharhiniformes, the European spotted dogfish, Scyliorhinus canicula (Scyliorhinidae), and the hammerhead shark, Sphyrna lewini (Carcharhinidae). The amino acid sequence of dogfish insulin was established as A-chain GIVDHCCRNT(10)CSLYDLEGYC(20)NQ and B-chain LPSQHLCGSH(10)LVETLYFVCG(20)QKGFYYVPKV(30). The primary structure of hammerhead shark insulin was similar to that of dogfish insulin with only 2 amino acid substitutions at A8 (R --> H) and B30 (V --> I). The elasmobranch insulins were markedly different from human insulin (17 amino acid substitutions) but all the residues in human insulin that are believed to be important in determining the receptor binding conformation (B6, B8, B11, B13, B23, B24, B25, A2, A3, and A19) have been conserved in the elasmobranch insulins with the exception of the conservative substitution Phe --> Tyr at B25. Consistent with this, dogfish and human insulin showed almost identical binding affinity to the recombinant solubilized human insulin receptor (K(D) values of 14.0 and 18.6 pM, respectively; relative potency 133%). Previous studies have shown that bovine insulin produces severe and sustained hypoglycemia in elasmobranchs but the effect is of slow onset. Bolus arterial injections of dogfish insulin (10 nmol x kg(-1)) into unanesthetized, fasting dogfish (n = 9) produced no changes in blood glucose, 3-hydroxybutyrate, and acetoacetate concentrations over a 4-h period. In a second series of experiments (n = 7), dogfish insulin (10 nmol x kg(-1)) produced a significant (P < 0.05) fall in blood glucose after 12 h that persisted for at least 48 h, but no change in ketone body concentrations. The data indicate that the metabolic actions of an endogenous elasmobranch insulin in an elasmobranch are similar to those previously described for mammalian insulin.

  8. Complexity in pH-Dependent Ribozyme Kinetics: Dark pKa Shifts and Wavy Rate-pH Profiles.

    Science.gov (United States)

    Frankel, Erica A; Bevilacqua, Philip C

    2018-02-06

    Charged bases occur in RNA enzymes, or ribozymes, where they play key roles in catalysis. Cationic bases donate protons and perform electrostatic catalysis, while anionic bases accept protons. We previously published simulations of rate-pH profiles for ribozymes in terms of species plots for the general acid and general base that have been useful for understanding how ribozymes respond to pH. In that study, we did not consider interaction between the general acid and general base or interaction with other species on the RNA. Since that report, diverse small ribozyme classes have been discovered, many of which have charged nucleobases or metal ions in the active site that can either directly interact and participate in catalysis or indirectly interact as "influencers". Herein, we simulate experimental rate-pH profiles in terms of species plots in which reverse protonated charged nucleobases interact. These analyses uncover two surprising features of pH-dependent enzyme kinetics. (1) Cooperativity between the general acid and general base enhances population of the functional forms of a ribozyme and manifests itself as hidden or "dark" pK a shifts, real pK a shifts that accelerate the reaction but are not readily observed by standard experimental approaches, and (2) influencers favorably shift the pK a s of proton-transferring nucleobases and manifest themselves as "wavy" rate-pH profiles. We identify parallels with the protein enzyme literature, including reverse protonation and wavelike behavior, while pointing out that RNA is more prone to reverse protonation. The complexities uncovered, which arise from simple pairwise interactions, should aid deconvolution of complex rate-pH profiles for RNA and protein enzymes and suggest veiled catalytic devices for promoting catalysis that can be tested by experiment and calculation.

  9. A speculated ribozyme site in the herpes simplex virus type 1 latency-associated transcript gene is not essential for a wild-type reactivation phenotype

    Science.gov (United States)

    Carpenter, Dale; Singh, Sukhpreet; Osorio, Nelson; Hsiang, Chinhui; Jiang, Xianzhi; Jin, Ling; Jones, Clinton; Wechsler, Steven L

    2010-01-01

    During herpes simplex virus-1 (HSV-1) latency in sensory neurons, LAT (latency-associated transcript) is the only abundantly expressed viral gene. LAT plays an important role in the HSV-1 latency-reactivation cycle, because LAT deletion mutants have a significantly decreased reactivation phenotype. Based solely on sequence analysis, it was speculated that LAT encodes a ribozyme that plays an important role in how LAT enhances the virus’ reactivation phenotype. Because LAT ribozyme activity has never been reported, we decided to test the converse hypothesis, namely, that this region of LAT does not encode a ribozyme function important for LAT’s ability to enhance the reactivation phenotype. We constructed a viral mutant (LAT-Rz) in which the speculated ribozyme consensus sequence was altered such that no ribozyme was encoded. We report here that LAT-Rz had a wild-type reactivation phenotype in mice, confirming the hypothesis that the speculated LAT ribozyme is not a dominant factor in stimulating the latency-reactivation cycle in mice. PMID:18982533

  10. Vesicle Encapsulation Studies Reveal that Single Molecule Ribozyme Heterogeneities Are Intrinsic

    Science.gov (United States)

    Okumus, Burak; Wilson, Timothy J.; Lilley, David M. J.; Ha, Taekjip

    2004-01-01

    Single-molecule measurements have revealed that what were assumed to be identical molecules can differ significantly in their static and dynamic properties. One of the most striking examples is the hairpin ribozyme, which was shown to exhibit two to three orders of magnitude variation in folding kinetics between molecules. Although averaged behavior of single molecules matched the bulk solution data, it was not possible to exclude rigorously the possibility that the variations around the mean values arose from different ways of interacting with the surface environment. To test this, we minimized the molecules' interaction with the surface by encapsulating DNA or RNA molecules inside 100- to 200-nm diameter unilamellar vesicles, following the procedures described by Haran and coworkers. Vesicles were immobilized on a supported lipid bilayer via biotin-streptavidin linkages. We observed no direct binding of DNA or RNA on the supported bilayer even at concentrations exceeding 100 nM, indicating that these molecules do not bind stably on the membrane. Since the vesicle diameter is smaller than the resolution of optical microscopy, the lateral mobility of the molecules is severely constrained, allowing long observation periods. We used fluorescence correlation spectroscopy, nuclease digestion, and external buffer exchange to show that the molecules were indeed encapsulated within the vesicles. When contained within vesicles, the natural form of the hairpin ribozyme exhibited 50-fold variation in both folding and unfolding rates in 0.5 mM Mg2+, which is identical to what was observed from the molecules tethered directly on the surface. This strongly indicates that the observed heterogeneity in dynamic properties does not arise as an artifact of surface attachment, but is intrinsic to the nature of the molecules. PMID:15454471

  11. Chemical Feasibility of the General Acid/Base Mechanism of glmS Ribozyme Self-Cleavage

    Czech Academy of Sciences Publication Activity Database

    Dubecký, M.; Walter, Nils G.; Šponer, Jiří; Otyepka, M.; Banáš, Pavel

    2015-01-01

    Roč. 103, č. 10 (2015), s. 550-562 ISSN 0006-3525 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR(CZ) GAP208/12/1878 Institutional support: RVO:68081707 Keywords : MOLECULAR-DYNAMICS SIMULATIONS * ACTIVE-SITE GUANINE * HAIRPIN RIBOZYME Subject RIV: BO - Biophysics Impact factor: 2.248, year: 2015

  12. Comparison of ab Initio, DFT, and Semiempirical QM/MM Approaches for Description of Catalytic Mechanism of Hairpin Ribozyme

    Czech Academy of Sciences Publication Activity Database

    Mlýnský, V.; Banáš, P.; Šponer, Jiří; van der Kamp, M.W.; Mulholland, A.J.; Otyepka, M.

    2014-01-01

    Roč. 10, č. 4 (2014), s. 1608-1622 ISSN 1549-9618 R&D Projects: GA ČR(CZ) GAP208/12/1878; GA ČR(CZ) GBP301/11/P558; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081707 Keywords : MOLECULAR-DYNAMICS SIMULATIONS * DELTA-VIRUS RIBOZYME * ACID-BASE CATALYSIS Subject RIV: BO - Biophysics Impact factor: 5.498, year: 2014

  13. Involvement of a cytosine side chain in proton transfer in the rate-determining step of ribozyme self-cleavage

    Science.gov (United States)

    Shih, I-hung; Been, Michael D.

    2001-01-01

    Ribozymes of hepatitis delta virus have been proposed to use an active-site cytosine as an acid-base catalyst in the self-cleavage reaction. In this study, we have examined the role of cytosine in more detail with the antigenomic ribozyme. Evidence that proton transfer in the rate-determining step involved cytosine 76 (C76) was obtained from examining cleavage activity of the wild-type and imidazole buffer-rescued C76-deleted (C76Δ) ribozymes in D2O and H2O. In both reactions, a similar kinetic isotope effect and shift in the apparent pKa indicate that the buffer is functionally substituting for the side chain in proton transfer. Proton inventory of the wild-type reaction supported a mechanism of a single proton transfer at the transition state. This proton transfer step was further characterized by exogenous base rescue of a C76Δ mutant with cytosine and imidazole analogues. For the imidazole analogues that rescued activity, the apparent pKa of the rescue reaction, measured under kcat/KM conditions, correlated with the pKa of the base. From these data a Brønsted coefficient (β) of 0.51 was determined for the base-rescued reaction of C76Δ. This value is consistent with that expected for proton transfer in the transition state. Together, these data provide strong support for a mechanism where an RNA side chain participates directly in general acid or general base catalysis of the wild-type ribozyme to facilitate RNA cleavage. PMID:11171978

  14. Competition Between Co(NH3)63+ and Inner Sphere Mg2+ Ions in the HDV Ribozyme

    Science.gov (United States)

    Gong, Bo; Chen, Jui-Hui; Bevilacqua, Philip C.; Golden, Barbara L.; Carey, Paul R.

    2009-01-01

    Divalent cations play critical structural and functional roles in many RNAs. While the hepatitis delta virus (HDV) ribozyme can undergo self-cleavage in the presence of molar concentrations of monovalent cations, divalent cations such as Mg2+ are required for efficient catalysis under physiological conditions. Moreover, the cleavage reaction can be inhibited with Co(NH3)63+, an analog of Mg(H2O)62+. Here, the binding of Mg2+ and Co(NH3)63+ to the HDV ribozyme are studied by Raman microscopic analysis of crystals. Raman difference spectra acquired at different metal ion conditions reveal changes in the ribozyme. When Mg2+ alone is introduced to the ribozyme, inner sphere coordination of Mg(H2O)x2+ (x≤5) to non-bridging PO2− oxygen, and changes in base stretches and phosphodiester group conformation are observed. In addition, binding of Mg2+ induces deprotonation of a cytosine assigned to the general acid C75, consistent with solution studies. When Co(NH3)63+ alone is introduced, deprotonation of C75 is again observed, as are distinctive changes in base vibrational ring modes and phosphodiester backbone conformation. In contrast to Mg2+ binding, Co(NH3)63+ binding does not perturb PO2− group vibrations, consistent with its ability to make only outer sphere contacts. Surprisingly, competitive binding studies reveal that Co(NH3)63+ ions displace some inner sphere-coordinated magnesium species, including ions coordinated to PO2− groups or the N7 of a guanine, likely G1 at the active site. These observations contrast with the tenet that Co(NH3)63+ ions displace only outer sphere magnesium ions. Overall, our data support two classes of inner sphere Mg2+-PO2− binding sites: sites that Co(NH3)63+ can displace, and others it cannot. PMID:19888753

  15. Robust Sub-harmonic Mixer at 340 GHz Using Intrinsic Resonances of Hammer-Head Filter and Improved Diode Model

    Science.gov (United States)

    Wang, Cheng; He, Yue; Lu, Bin; Jiang, Jun; Miao, Li; Deng, Xian-Jin; Xiong, Yong-zhong; Zhang, Jian

    2017-11-01

    This paper presents a sub-harmonic mixer at 340 GHz based on anti-parallel Schottky diodes (SBDs). Intrinsic resonances in low-pass hammer-head filter have been adopted to enhance the isolation for different harmonic components, while greatly minimizing the transmission loss. The application of new DC grounding structure, impedance matching structure, and suspended micro-strip mitigates the negative influences of fabrication errors from metal cavity, quartz substrate, and micro-assembly. An improved lumped element equivalent circuit model of SBDs guarantees the accuracy of simulation, which takes current-voltage (I/V) behavior, capacitance-voltage (C/V) behavior, carrier velocity saturation, DC series resistor, plasma resonance, skin effect, and four kinds of noise generation mechanisms into consideration thoroughly. The measurement indicates that with local oscillating signal of 2 mW, the lowest double sideband conversion loss is 5.5 dB at 339 GHz; the corresponding DSB noise temperature is 757 K. The 3 dB bandwidth of conversion loss is 50 GHz from 317 to 367 GHz.

  16. Importance of specific nucleotides in the folding of the natural form of the hairpin ribozyme.

    Science.gov (United States)

    Wilson, T J; Zhao, Z Y; Maxwell, K; Kontogiannis, L; Lilley, D M

    2001-02-20

    The hairpin ribozyme in its natural context consists of two loops in RNA duplexes that are connected as arms of a four-way helical junction. Magnesium ions induce folding into the active conformation in which the two loops are in proximity. In this study, we have investigated nucleotides that are important to this folding process. We have analyzed the folding in terms of the cooperativity and apparent affinity for magnesium ions as a function of changes in base sequence and functional groups, using fluorescence resonance energy transfer. Our results suggest that the interaction between the loops is the sum of a number of component interactions. Some sequence variants such as A10U, G+1A, and C25U exhibit loss of cooperativity and reduced affinity of apparent magnesium ion binding. These variants are also very impaired in ribozyme cleavage activity. Nucleotides A10, G+1, and C25 thus appear to be essential in creating the conformational environment necessary for ion binding. The double variant G+1A/C25U exhibits a marked recovery of both folding and catalytic activity compared to either individual variant, consistent with the proposal of a triple-base interaction among A9, G+1, and C25 [Pinard, R., Lambert, D., Walter, N. G., Heckman, J. E., Major, F., and Burke, J. M. (1999) Biochemistry 38, 16035-16039]. However, substitution of A9 leads to relatively small changes in folding properties and cleavage activity, and the double variant G+1DAP/C25U (DAP is 2,6-diaminopurine), which could form an isosteric triple-base interaction, exhibits folding and cleavage activities that are both very impaired compared to those of the natural sequence. Our results indicate an important role for a Watson--Crick base pair between G+1 and C25; this may be buttressed by an interaction with A9, but the loss of this has less significant consequences for folding. 2'-Deoxyribose substitution leads to folding with reduced magnesium ion affinity in the following order: unmodified RNA > dA9

  17. Template-directed ligation of tethered mononucleotides by t4 DNA ligase for kinase ribozyme selection.

    Directory of Open Access Journals (Sweden)

    David G Nickens

    Full Text Available BACKGROUND: In vitro selection of kinase ribozymes for small molecule metabolites, such as free nucleosides, will require partition systems that discriminate active from inactive RNA species. While nucleic acid catalysis of phosphoryl transfer is well established for phosphorylation of 5' or 2' OH of oligonucleotide substrates, phosphorylation of diffusible small molecules has not been demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: This study demonstrates the ability of T4 DNA ligase to capture RNA strands in which a tethered monodeoxynucleoside has acquired a 5' phosphate. The ligation reaction therefore mimics the partition step of a selection for nucleoside kinase (deoxyribozymes. Ligation with tethered substrates was considerably slower than with nicked, fully duplex DNA, even though the deoxynucleotides at the ligation junction were Watson-Crick base paired in the tethered substrate. Ligation increased markedly when the bridging template strand contained unpaired spacer nucleotides across from the flexible tether, according to the trends: A(2>A(1>A(3>A(4>A(0>A(6>A(8>A(10 and T(2>T(3>T(4>T(6 approximately T(1>T(8>T(10. Bridging T's generally gave higher yield of ligated product than bridging A's. ATP concentrations above 33 microM accumulated adenylated intermediate and decreased yields of the gap-sealed product, likely due to re-adenylation of dissociated enzyme. Under optimized conditions, T4 DNA ligase efficiently (>90% joined a correctly paired, or TratioG wobble-paired, substrate on the 3' side of the ligation junction while discriminating approximately 100-fold against most mispaired substrates. Tethered dC and dG gave the highest ligation rates and yields, followed by tethered deoxyinosine (dI and dT, with the slowest reactions for tethered dA. The same kinetic trends were observed in ligase-mediated capture in complex reaction mixtures with multiple substrates. The "universal" analog 5-nitroindole (dNI did not support ligation when

  18. Limits of neutral drift: lessons from the in vitro evolution of two ribozymes.

    Science.gov (United States)

    Petrie, Katherine L; Joyce, Gerald F

    2014-10-01

    The relative contributions of adaptive selection and neutral drift to genetic change are unknown but likely depend on the inherent abundance of functional genotypes in sequence space and how accessible those genotypes are to one another. To better understand the relative roles of selection and drift in evolution, local fitness landscapes for two different RNA ligase ribozymes were examined using a continuous in vitro evolution system under conditions that foster the capacity for neutral drift to mediate genetic change. The exploration of sequence space was accelerated by increasing the mutation rate using mutagenic nucleotide analogs. Drift was encouraged by carrying out evolution within millions of separate compartments to exploit the founder effect. Deep sequencing of individuals from the evolved populations revealed that the distribution of genotypes did not escape the starting local fitness peak, remaining clustered around the sequence used to initiate evolution. This is consistent with a fitness landscape where high-fitness genotypes are sparse and well isolated, and suggests, at least in this context, that neutral drift alone is not a primary driver of genetic change. Neutral drift does, however, provide a repository of genetic variation upon which adaptive selection can act.

  19. Global phylogeography with mixed-marker analysis reveals male-mediated dispersal in the endangered scalloped hammerhead shark (Sphyrna lewini.

    Directory of Open Access Journals (Sweden)

    Toby S Daly-Engel

    Full Text Available The scalloped hammerhead shark, Sphyrna lewini, is a large endangered predator with a circumglobal distribution, observed in the open ocean but linked ontogenetically to coastal embayments for parturition and juvenile development. A previous survey of maternal (mtDNA markers demonstrated strong genetic partitioning overall (global Φ(ST = 0.749 and significant population separations across oceans and between discontinuous continental coastlines.We surveyed the same global range with increased sample coverage (N = 403 and 13 microsatellite loci to assess the male contribution to dispersal and population structure. Biparentally inherited microsatellites reveal low or absent genetic structure across ocean basins and global genetic differentiation (F(ST = 0.035 over an order of magnitude lower than the corresponding measures for maternal mtDNA lineages (Φ(ST = 0.749. Nuclear allelic richness and heterozygosity are high throughout the Indo-Pacific, while genetic structure is low. In contrast, allelic diversity is low while population structure is higher for populations at the ends of the range in the West Atlantic and East Pacific.These data are consistent with the proposed Indo-Pacific center of origin for S. lewini, and indicate that females are philopatric or adhere to coastal habitats while males facilitate gene flow across oceanic expanses. This study includes the largest sampling effort and the most molecular loci ever used to survey the complete range of a large oceanic predator, and findings emphasize the importance of incorporating mixed-marker analysis into stock assessments of threatened and endangered shark species.

  20. Molecular trade-offs in RNA ligases affected the modular emergence of complex ribozymes at the origin of life

    Science.gov (United States)

    Dhar, Nisha; Weinberg, Marc S.; Michod, Richard E.; Durand, Pierre M.

    2017-09-01

    In the RNA world hypothesis complex, self-replicating ribozymes were essential. For the emergence of an RNA world, less is known about the early processes that accounted for the formation of complex, long catalysts from small passively formed molecules. The functional role of small sequences has not been fully explored and, here, a possible role for smaller ligases is demonstrated. An established RNA polymerase model, the R18, was truncated from the 3' end to generate smaller molecules. All the molecules were investigated for self-ligation functions with a set of oligonucleotide substrates without predesigned base pairing. The smallest molecule that exhibited self-ligation activity was a 40-nucleotide RNA. It also demonstrated the greatest functional flexibility as it was more general in the kinds of substrates it ligated to itself although its catalytic efficiency was the lowest. The largest ribozyme (R18) ligated substrates more selectively and with greatest efficiency. With increase in size and predicted structural stability, self-ligation efficiency improved, while functional flexibility decreased. These findings reveal that molecular size could have increased from the activity of small ligases joining oligonucleotides to their own end. In addition, there is a size-associated molecular-level trade-off that could have impacted the evolution of RNA-based life.

  1. Molecular trade-offs in RNA ligases affected the modular emergence of complex ribozymes at the origin of life

    Science.gov (United States)

    Weinberg, Marc S.; Michod, Richard E.

    2017-01-01

    In the RNA world hypothesis complex, self-replicating ribozymes were essential. For the emergence of an RNA world, less is known about the early processes that accounted for the formation of complex, long catalysts from small passively formed molecules. The functional role of small sequences has not been fully explored and, here, a possible role for smaller ligases is demonstrated. An established RNA polymerase model, the R18, was truncated from the 3′ end to generate smaller molecules. All the molecules were investigated for self-ligation functions with a set of oligonucleotide substrates without predesigned base pairing. The smallest molecule that exhibited self-ligation activity was a 40-nucleotide RNA. It also demonstrated the greatest functional flexibility as it was more general in the kinds of substrates it ligated to itself although its catalytic efficiency was the lowest. The largest ribozyme (R18) ligated substrates more selectively and with greatest efficiency. With increase in size and predicted structural stability, self-ligation efficiency improved, while functional flexibility decreased. These findings reveal that molecular size could have increased from the activity of small ligases joining oligonucleotides to their own end. In addition, there is a size-associated molecular-level trade-off that could have impacted the evolution of RNA-based life. PMID:28989747

  2. What Expands in an Expanding Universe?

    Directory of Open Access Journals (Sweden)

    JOSÉ A. DE FREITAS PACHECO

    2015-12-01

    Full Text Available ABSTRACT In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes.

  3. What Expands in an Expanding Universe?

    Science.gov (United States)

    Pacheco, José A De Freitas

    2015-01-01

    In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative) of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM) all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes.

  4. A Conserved Target Site in HIV-1 Gag RNA is Accessible to Inhibition by Both an HDV Ribozyme and a Short Hairpin RNA

    Directory of Open Access Journals (Sweden)

    Robert J Scarborough

    2014-01-01

    Full Text Available Antisense-based molecules targeting HIV-1 RNA have the potential to be used as part of gene or drug therapy to treat HIV-1 infection. In this study, HIV-1 RNA was screened to identify more conserved and accessible target sites for ribozymes based on the hepatitis delta virus motif. Using a quantitative screen for effects on HIV-1 production, we identified a ribozyme targeting a highly conserved site in the Gag coding sequence with improved inhibitory potential compared to our previously described candidates targeting the overlapping Tat/Rev coding sequence. We also demonstrate that this target site is highly accessible to short hairpin directed RNA interference, suggesting that it may be available for the binding of antisense RNAs with different modes of action. We provide evidence that this target site is structurally conserved in diverse viral strains and that it is sufficiently different from the human transcriptome to limit off-target effects from antisense therapies. We also show that the modified hepatitis delta virus ribozyme is more sensitive to a mismatch in its target site compared to the short hairpin RNA. Overall, our results validate the potential of a new target site in HIV-1 RNA to be used for the development of antisense therapies.

  5. Expanding Thurston maps

    CERN Document Server

    Bonk, Mario

    2017-01-01

    This monograph is devoted to the study of the dynamics of expanding Thurston maps under iteration. A Thurston map is a branched covering map on a two-dimensional topological sphere such that each critical point of the map has a finite orbit under iteration. It is called expanding if, roughly speaking, preimages of a fine open cover of the underlying sphere under iterates of the map become finer and finer as the order of the iterate increases. Every expanding Thurston map gives rise to a fractal space, called its visual sphere. Many dynamical properties of the map are encoded in the geometry of this visual sphere. For example, an expanding Thurston map is topologically conjugate to a rational map if and only if its visual sphere is quasisymmetrically equivalent to the Riemann sphere. This relation between dynamics and fractal geometry is the main focus for the investigations in this work.

  6. Silicon microfabricated beam expander

    International Nuclear Information System (INIS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-01-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed

  7. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  8. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  9. Detection of innersphere interactions between magnesium hydrate and the phosphate backbone of the HDV ribozyme using Raman crystallography.

    Science.gov (United States)

    Gong, Bo; Chen, Yuanyuan; Christian, Eric L; Chen, Jui-Hui; Chase, Elaine; Chadalavada, Durga M; Yajima, Rieko; Golden, Barbara L; Bevilacqua, Philip C; Carey, Paul R

    2008-07-30

    A Raman microscope and Raman difference spectroscopy are used to detect the vibrational signature of RNA-bound magnesium hydrate in crystals of hepatitis delta virus (HDV) ribozyme and to follow the effects of magnesium hydrate binding to the nonbridging phosphate oxygens in the phosphodiester backbone. There is a correlation between the Raman intensity of the innersphere magnesium hydrate signature peak, near 322 cm-1, and the intensity of the PO2- symmetric stretch, near 1100 cm-1, perturbed by magnesium binding, demonstrating direct observation of -PO2-...Mg2+(H2O)x innersphere complexes. The complexes may be pentahydrates (x = 5) and tetrahydrates (x = 4). The assignment of the Raman feature near 322 cm-1 to a magnesium hydrate species is confirmed by isotope shifts observed in D2O and H218O that are semiquantitatively reproduced by calculations. The standardized intensity changes in the 1100 cm-1 PO2- feature seen upon magnesium hydrate binding indicates that there are approximately 5 innersphere Mg2+...-O2P contacts per HDV molecule when the crystal is exposed to a solution containing 20 mM magnesium.

  10. ExpandED Options: Learning beyond High School Walls

    Science.gov (United States)

    ExpandED Schools, 2014

    2014-01-01

    Through ExpandED Options by TASC, New York City high school students get academic credit for learning career-related skills that lead to paid summer jobs. Too many high school students--including those most likely to drop out--are bored or see classroom learning as irrelevant. ExpandED Options students live the connection between mastering new…

  11. Grazing incidence beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  12. Expanding the HAWC Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Johanna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-17

    The High Altitude Water Cherenkov Gamma-Ray Observatory is expanding its current array of 300 water tanks to include 350 outrigger tanks to increase sensitivity to gamma rays above 10 TeV. This involves creating and testing hardware with which to build the new tanks, including photomultiplier tubes, high voltage supply units, and flash analog to digital converters. My responsibilities this summer included preparing, testing and calibrating that equipment.

  13. General base catalysis for cleavage by the active-site cytosine of the hepatitis delta virus ribozyme: QM/MM calculations establish chemical feasibility

    Czech Academy of Sciences Publication Activity Database

    Banáš, Pavel; Rulíšek, Lubomír; Hánošová, V.; Svozil, Daniel; Walter, N.G.; Šponer, Jiří; Otyepka, Michal

    2008-01-01

    Roč. 112, č. 35 (2008), s. 11177-11187 ISSN 1520-6106 R&D Projects: GA MŠk LC512; GA MŠk(CZ) LC06030; GA AV ČR(CZ) IAA400040802; GA AV ČR 1QS500040581 Grant - others:NIH(US) GM62357 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : HDV ribozyme * catalysis * QM/MM calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.189, year: 2008

  14. The expanding universe

    CERN Document Server

    Lew, Kristi

    2011-01-01

    People have always been fascinated with the stars above and the universe that contains them. Over the years, astronomers have developed numerous theories to explain how the universe began, how it works, and what its ultimate fate will be. But all of the scientists' questions are far from answered. The Expanding Universe goes beyond the creation of the universe to explain how scientists think the universe works, grows, and changes, including what great thinkers Isaac Newton and Albert Einstein had to say about its fate. Readers will also learn about how researchers are slowly shedding light on

  15. Expanding Your Horizon 2015

    CERN Multimedia

    Kaltenhauser, Kristin

    2015-01-01

    Expanding your horizons is a bi-annual “Science Day” for girls aged 11 to 14, held at the University of Geneva on 14 November. The girls had the opportunity to take part in hands-on workshops held by local professional women in the field of science, mathematics, engineering and technology. For the fourth time, CERN was part of this event, offering three workshops as well as a booth at the Discovery Fair, including Higgnite, an interactive visualization of the Higgs Field.

  16. Bigelow Expandable Activity Module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Bigelow Expandable Activity Module (BEAM) project is a NASA-industry partnership with Bigelow Aerospace (BA) that has developing the first human-rated expandable...

  17. Tissue expander infections in children: look beyond the expander pocket.

    Science.gov (United States)

    Mason, A C; Davison, S P; Manders, E K

    1999-11-01

    Infection of the expander pocket is the most common complication encountered with soft-tissue expansion. It is usually due to direct inoculation with skin flora either at the time of expander insertion or from extrusion of the device. The authors report two cases of infection of tissue expanders in which the children had concomitant infected sites distant from the prosthesis. Etiological bacteria of common pediatric infections like otitis media and pharyngitis were cultured from the infected expander pocket, raising suspicion that translocation of the organism to the expander had occurred. Aggressive antibiotic treatment, removal of the prosthesis, and flap advancement is advocated.

  18. The expanding EU

    DEFF Research Database (Denmark)

    Zank, Wolfgang

    In this paper I try to explore whether the EU can go on expanding and thereby become culturally ever more diversified, and at the same retain its stability. The answer is, in principle, affirmative. Europe has always been much diversified, and therefore it is not possible to define a European...... identity in terms of particular cultural traditions. However, in spite of their diversity, the EU-member countries are united by their adherence to the principles of democracy, rule by law and human rights. Countries which do not share this basic consensus would not be accepted as members, nor is it likely...... that they would apply for it. An essential part is the willingness of member states to accept a reduction of national sovereignty on some important policy fields. The EU project is basically about lifting the principles of democracy and rule by law on the international level, most and foremost among the member...

  19. Expanding hollow metal rings

    Science.gov (United States)

    Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

    2009-03-17

    A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

  20. The expanding plasma jet

    International Nuclear Information System (INIS)

    Sanden, M.C.M. van den.

    1991-01-01

    This thesis concerns the fundamental aspects of an argon plasma expanding from a cascaded arc. This type of plasma is not only used for fundamental research but also for technologically orientated research on plasma deposition and plasma sources. The important characteristics of the plasma are a strong supersonic expansion in which the neutral particle and ion densities decrease three orders of magnitude, followed by a stationary shock front. After the shock front the plasma expands further subsonically. A part of this thesis is devoted to the discussion of a newly constructed combined Thomson-Rayleigh scattering set up. With this set up the electron density, the electron temperature and the neutral particle density are measured locally in the plasma for different conditions. In the analysis of the measured spectra weak coherent effects and the measured apparatus profile are included. The inaccuracies are small, ranging from 1 to 4 percent for the electron density and 2 to 6 percent for the electron temperature, depending on the plasma conditions. The inaccuracy of the neutral particle density determination is larger and ranges from 10 to 50 percent. The detection limits for the electron and neutral particle density are 7.10 17 m -3 and 1.10 20 m -3 respectively. A side path in this thesis is the derivation of the Saha equation for a two-temperature plasma. The reason for this derivation was the dispute in the literature about the correct form of this equation. In this thesis it is shown, from the correct extension of the second law of thermodynamics and from the non-equilibrium formalism of Zubarev, That in the limit of m e /m h ->0 the generalized Saha equation depends on the electron temperature only. (author). 221 refs.; 54 figs.; 13 tabs

  1. The Artful Universe Expanded

    International Nuclear Information System (INIS)

    Bassett, B A

    2005-01-01

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music-a new type of 'cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson, hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature's code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one's mind a vision that unifies science, art and culture and glimpse a universal tapestry of great beauty. (book review)

  2. The Artful Universe Expanded

    Energy Technology Data Exchange (ETDEWEB)

    Bassett, B A [Institute of Cosmology and Gravitation, University of Portsmouth (United Kingdom)

    2005-07-29

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music-a new type of 'cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson, hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature's code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one's mind a vision that unifies science, art and culture and glimpse a universal tapestry of great

  3. The Artful Universe Expanded

    Science.gov (United States)

    Barrow, John D.

    2005-07-01

    Our love of art, writes John Barrow, is the end product of millions of years of evolution. How we react to a beautiful painting or symphony draws upon instincts laid down long before humans existed. Now, in this enhanced edition of the highly popular The Artful Universe , Barrow further explores the close ties between our aesthetic appreciation and the basic nature of the Universe. Barrow argues that the laws of the Universe have imprinted themselves upon our thoughts and actions in subtle and unexpected ways. Why do we like certain types of art or music? What games and puzzles do we find challenging? Why do so many myths and legends have common elements? In this eclectic and entertaining survey, Barrow answers these questions and more as he explains how the landscape of the Universe has influenced the development of philosophy and mythology, and how millions of years of evolutionary history have fashioned our attraction to certain patterns of sound and color. Barrow casts the story of human creativity and thought in a fascinating light, considering such diverse topics as our instinct for language, the origins and uses of color in nature, why we divide time into intervals as we do, the sources of our appreciation of landscape painting, and whether computer-generated fractal art is really art. Drawing on a wide variety of examples, from the theological questions raised by St. Augustine and C.S. Lewis to the relationship between the pure math of Pythagoras and the music of the Beatles, The Artful Universe Expanded covers new ground and enters a wide-ranging debate about the meaning and significance of the links between art and science.

  4. The Expanding Universe: Dark Energy

    Energy Technology Data Exchange (ETDEWEB)

    Lincoln, Don [Fermilab; Nord, Brian [Fermilab

    2014-09-01

    In 1998, observations of distant supernovae led physicists that not only was the universe expanding, but the expansion was speeding up. In this article, we describe the evidence for an expanding universe and describe what physicists and cosmologists have learned in the intervening years. The target audience for this article is high school physics teachers and college physics professors at teaching institutions.

  5. The expanding universe: an introduction

    OpenAIRE

    Pössel, Markus

    2017-01-01

    An introduction to the physics and mathematics of the expanding universe, using no more than high-school level / undergraduate mathematics. Covered are the basics of scale factor expansion, the dynamics of the expanding universe, various distance concepts and the generalized redshift-luminosity relation, among other topics.

  6. New generation expandable sand screens

    OpenAIRE

    Syltøy, Christer

    2014-01-01

    Master's thesis in Petroleum engineering This thesis aims to give a general insight into sand control and various sorts of sand control measures and applications of sand control tools. Special focus will be given to expandable sand screens – a technology which came about in the late 1990’s through the use of flexible, expandable tubulars as base pipe in sand screens. More specifically Darcy’s Hydraulic Endurance Screens, a compliant sand screen system using hydraulic activation, and the fu...

  7. Neutrinos in an expanding Universe

    International Nuclear Information System (INIS)

    Wigmans, Richard

    2015-01-01

    The Universe contains several billion neutrinos for each nucleon. In this paper, we follow the history of these relic neutrinos as the Universe expanded. At present, their typical velocity is a few hundred km/s and, therefore, their spectra are affected by gravitational forces. This may have led to a phenomenon that could explain two of todays great mysteries: The large-scale structure of the Universe and the increasing rate at which it expands. (paper)

  8. Flow boiling in expanding microchannels

    CERN Document Server

    Alam, Tamanna

    2017-01-01

    This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

  9. Stability of expanded plasma focus

    International Nuclear Information System (INIS)

    Soliman, H.M.

    1994-01-01

    In this study, the stabilization of the expanded plasma focus formed by 4.5 kJ plasma focus device of Mather type by magnetic field is presented. The experimental results of the induced axial magnetic field and electric probe measurements of the expanded plasma focus show that, the plasma consists of three plasmoids, electron temperature measurements off the plasmoids at a point close to the muzzle are 26 eV, 30 eV and 27 eV respectively and the electron densities are 6.6 x 10 14 , 6.1 x 10 14 / cm 3 respectively. The presence of external axial magnetic field (B 2 = 1.6 kg) at the mid distance between the breech and the muzzle has a less effect on the stability of expanded focus and it causes a restriction for the plasma motion. the electron temperature of the three plasmoids are found to increase in that case by 23%, 18.5% respectively. When this axial magnetic field is applied at the muzzle end, it leads to a more stable expanded plasma focus which consists mainly of one plasmoid with electron temperature of 39 eV and density of 3.4 x 10 14 / cm 3 . 5 figs

  10. 'In situ' expanded graphite extinguishant

    International Nuclear Information System (INIS)

    Cao Qixin; Shou Yuemei; He Bangrong

    1987-01-01

    This report is concerning the development of the extinguishant for sodium fire and the investigation of its extinguishing property. The experiment result shows that 'in situ' expanded graphite developed by the authors is a kind of extinguishant which extinguishes sodium fire quickly and effectively and has no environment pollution during use and the amount of usage is little

  11. EFFECT OF INCORPORATING EXPANDED POLYSTYRENE ...

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... Incorporating expanded polystyrene granules in concrete matrix can produce lightweight polystyrene aggregate concrete of ... structure. [1] reported that the standard workability tests are not suitable for the polystyrene aggregate concrete since they are sensitive to the unit weight of concrete. [2] made ...

  12. Expanding the Universe of Education.

    Science.gov (United States)

    Parsons, Elizabeth

    1996-01-01

    Definitions of "education" and "rural" are debunked and expanded. The three major tasks of rural education are educating people to understand their own needs, the unavoidable changes that will transform rural Australia within their lifetimes, and the range of technologies that can enhance their well-being. Presents a strategy…

  13. Expanding the Game Design Space

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel; Majgaard, Gunver

    2016-01-01

    This article considers game design research in educational settings. Its focus is on how undergraduate students – particularly engineering students – learn computer game design. From observations conducted during our game design courses we have developed a model of expanded game design space...... layer establishes correspondence between formal elements of computer games and the structure of problem-based creativity. It addresses how game design challenges should be formulated and how creative solutions can be measured. The fourth and final layer demonstrates how clear framing can act....... It encapsulates the entire development process from the first ideas to the final game with emphasis on game design thinking. Our model of expanded game design space consists of four separate – yet interconnected – layers in the process of game development. The first layer addresses the importance of framing...

  14. Seal-less cryogenic expander

    International Nuclear Information System (INIS)

    Faria, L.E.; Christopher, E.H.

    1987-01-01

    In an expander for use in a split Stirling cycle refrigeration system of the type wherein a displacer moves with reciprocating motion inside an expander housing, and wherein a plunger force and a regenerator force are formed on the displacer, the plunger force cyclically varying and having a time of minimum and maximum plunger force amplitude, and the regenerator force cyclically varying and having a time of minimum and maximum regenerator force amplitude, the improvement is described comprising: (a) means for maintaining displacer forces, such that the maximum plunger force amplitude is substantially equal to the maximum regenerator force amplitude; and (b) means for adjusting a time difference, the time difference being the time between the time of maximum plunger force and the time of maximum regenerator force such that a measure of the cooling power of the refrigeration system is maximized

  15. DISRUPTIVE TECHNOLOGIES: AN EXPANDED VIEW

    OpenAIRE

    JAMES M. UTTERBACK; HAPPY J. ACEE

    2005-01-01

    The term "disruptive technology" as coined by Christensen (1997, The Innovator's Dilemma; How New Technologies Cause Great Firms to Fail. Harvard Business School Press) refers to a new technology having lower cost and performance measured by traditional criteria, but having higher ancillary performance. Christensen finds that disruptive technologies may enter and expand emerging market niches, improving with time and ultimately attacking established products in their traditional markets. This...

  16. Entropy in an expanding universe

    International Nuclear Information System (INIS)

    Frautschi, S.

    1982-01-01

    The question of how the observed evolution of organized structures from initial chaos in the expanding universe can be reconciled with the laws of statistical mechanics is studied, with emphasis on effects of the expansion and gravity. Some major sources of entropy increase are listed. An expanding causal region is defined in which the entropy, though increasing, tends to fall further and further behind its maximum possible value, thus allowing for the development of order. The related questions of whether entropy will continue increasing without limit in the future, and whether such increase in the form of Hawking radiation or radiation from positronium might enable life to maintain itself permanently, are considered. Attempts to find a scheme for preserving life based on solid structures fail because events such as quantum tunneling recurrently disorganize matter on a very long but fixed time scale, whereas all energy sources slow down progressively in an expanding universe. However, there remains hope that other modes of life capable of maintaining themselves permanently can be found

  17. Expander for Thin-Wall Tubing

    Science.gov (United States)

    Pessin, R.

    1983-01-01

    Tool locally expands small-diameter tubes. Tube expander locally expands and deforms tube: Compressive lateral stress induced in elastomeric sleeve by squeezing axially between two metal tool parts. Adaptable to situations in which tube must have small bulge for mechanical support or flow control.

  18. Instability of expanding bacterial droplets.

    Science.gov (United States)

    Sokolov, Andrey; Rubio, Leonardo Dominguez; Brady, John F; Aranson, Igor S

    2018-04-03

    Suspensions of motile bacteria or synthetic microswimmers, termed active matter, manifest a remarkable propensity for self-organization, and formation of large-scale coherent structures. Most active matter research deals with almost homogeneous in space systems and little is known about the dynamics of strongly heterogeneous active matter. Here we report on experimental and theoretical studies on the expansion of highly concentrated bacterial droplets into an ambient bacteria-free fluid. The droplet is formed beneath a rapidly rotating solid macroscopic particle inserted in the suspension. We observe vigorous instability of the droplet reminiscent of a violent explosion. The phenomenon is explained in terms of continuum first-principle theory based on the swim pressure concept. Our findings provide insights into the dynamics of active matter with strong density gradients and significantly expand the scope of experimental and analytic tools for control and manipulation of active systems.

  19. Preventive Ethics Through Expanding Education.

    Science.gov (United States)

    Ho, Anita; MacDonald, Lisa Mei-Hwa; Unger, David

    2016-03-01

    Healthcare institutions have been making increasing efforts to standardize consultation methodology and to accredit both bioethics training programs and the consultants accordingly. The focus has traditionally been on the ethics consultation as the relevant unit of ethics intervention. Outcome measures are studied in relation to consultations, and the hidden assumption is that consultations are the preferred or best way to address day-to-day ethical dilemmas. Reflecting on the data from an internal quality improvement survey and the literature, we argue that having general ethics education as a key function of ethics services may be more important in meeting the contemporaneous needs of acute care settings. An expanded and varied ethics education, with attention to the time constraints of healthcare workers' schedules, was a key recommendation brought forward by survey respondents. Promoting ethical reflection and creating a culture of ethics may serve to prevent ethical dilemmas or mitigate their effects.

  20. SHEAR ACCELERATION IN EXPANDING FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, F. M. [ZAH, Institut für Theoretische Astrophysik, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Duffy, P., E-mail: frank.rieger@mpi-hd.mpg.de, E-mail: peter.duffy@ucd.ie [University College Dublin, Belfield, Dublin 4 (Ireland)

    2016-12-10

    Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).

  1. Nonlinear beam expander for ESNIT

    International Nuclear Information System (INIS)

    Rusthoi, D.P.; Blind, B.; Garnett, R.W.; Hanna, D.S.; Jason, A.J.; Kraus, R.H. Jr.; Neri, F.

    1994-01-01

    We describe the design of a beam-redistribution and expansion system for the Japanese Atomic Energy Research Institute (JAERI) Energy Selective Neutron Irradiation Test Facility (ESNIT). The system tailors the beam exiting a deuteron accelerator at energies from 20 to 35 MeV for deposition on a lithium neutron-production target. A uniform beam-intensity distribution in a well-defined irradiation area is inquired at the target and is achieved by the use of nonlinear elements. The design of the high-energy beam transport (HEBT) for ESNIT includes a 90 degree achromatic bend, a matching section with an energy-compacting cavity, a nonlinear beam expander, a target imager, a shielding dipole, and an rf-cavity system to add energy spread to the beam before it impinges on the target. The system meets performance requirements at multiple energies and currents, and for different spot sizes on target

  2. Microbial Biofilms and Breast Tissue Expanders

    Directory of Open Access Journals (Sweden)

    Melissa J. Karau

    2013-01-01

    Full Text Available We previously developed and validated a vortexing-sonication technique for detection of biofilm bacteria on the surface of explanted prosthetic joints. Herein, we evaluated this technique for diagnosis of infected breast tissue expanders and used it to assess colonization of breast tissue expanders. From April 2008 to December 2011, we studied 328 breast tissue expanders at Mayo Clinic, Rochester, MN, USA. Of seven clinically infected breast tissue expanders, six (85.7% had positive cultures, one of which grew Propionibacterium species. Fifty-two of 321 breast tissue expanders (16.2%, 95% CI, 12.3–20.7% without clinical evidence of infection also had positive cultures, 45 growing Propionibacterium species and ten coagulase-negative staphylococci. While vortexing-sonication can detect clinically infected breast tissue expanders, 16 percent of breast tissue expanders appear to be asymptomatically colonized with normal skin flora, most commonly, Propionibacterium species.

  3. Probing adenine rings and backbone linkages using base specific isotope-edited Raman spectroscopy: application to group II intron ribozyme domain V.

    Science.gov (United States)

    Chen, Yuanyuan; Eldho, Nadukkudy V; Dayie, T Kwaku; Carey, Paul R

    2010-04-27

    with the differences in hydration radii. These subtle differences in electrostatic interactions may be related to observed variations in catalytic activity. For a reconstructed ribozyme comprising domains 1-3 (D123) connected in cis plus domain 5 (D5) supplied in trans, cleavage of spliced exon substrates in the presence of magnesium and K(+) or Cs(+) is more efficient than that in the presence of magnesium with Na(+) or Li(+).

  4. Expanding the grid in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Horner, M. [AltaLink Management Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed some of the changes and strategies that are currently being adopted by AltaLink to expand Alberta's electricity grid in relation to wind power development. The company is Alberta's largest transmission facility operator. Wind power currently accounts for approximately 5 percent of the province's generation mix. Applications for new wind farms will increase Alberta's 629 MW of wind power generation capacity to 5530 MW. Alberta's transmission regulation requires that 100 percent of in-merit generation can occur when transmission facilities are in service, and that 95 percent of in-merit generation can occur under abnormal operating conditions. A new transmission line is being constructed in the Pincher Creek and Lethbridge region as part of a southern Alberta transmission reinforcement project. The Alberta Electric System Operator (AESO) and Canadian Wind Energy Association (CanWEA) are working together to ensure that adequate resources are available while system reliability is maintained. The Ardenville wind farm is the first wind power project to be energized under the new connection model launched by the AESO. The connection model was developed to identify, connect, and construct new energy projects. The project will also identify connection routes with the lowest overall impact on the province. Alberta will also continue to implement technologies that ensure the development of a smart grid. tabs., figs.

  5. Attitudes toward expanding nurses' authority.

    Science.gov (United States)

    Kerzman, Hana; Van Dijk, Dina; Eizenberg, Limor; Khaikin, Rut; Phridman, Shoshi; Siman-Tov, Maya; Goldberg, Shoshi

    2015-01-01

    In recent years, an increasing number of care procedures previously under the physician's authority have been placed in the hands of registered nurses. The purpose of this study was to examine the attitudes of nurses towards expanding nurses' authority and the relationships between these attitudes and job satisfaction facets, professional characteristics, and demographics. A cross-sectional study was conducted between 2010 and 2011 in three major medical centers in Israel. Participants included 833 nurses working in 89 departments. Attitudes toward the expansion of nurses' authority were assessed by self-report questionnaire, as well as job satisfaction facets including perception of professional autonomy, nurse-physician working relations, workload and burnout, perceptions of quality of care, and nursing staff satisfaction at work. Nurses reported positive attitudes toward the expansion of nurses' authority and moderate attitudes for interpretation of diagnostic tests in selected situations. The results of multivariate regression analyses demonstrate that the nurses' satisfaction from professional autonomy and work relations were the most influential factors in explaining their attitudes toward the expansion of nurses' authority. In addition, professionally young nurses tend to be more positive regarding changes in nurses' authority. In the Israeli reality of a nurse's shortage, we are witnessing professional transitions toward expansion of the scope of nurses' accountability and decision-making authority. The current research contributes to our understanding of attitudes toward the expansion of nurses' authority among the nursing staffs. The findings indicate the necessity of redefining the scope of nursing practice within the current professional context.

  6. Discovery of Uniformly Expanding Universe

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2012-01-01

    Full Text Available Saul Perlmutter and the Brian Schmidt – Adam Riess teams reported that their Friedmann-model GR-based analysis of their supernovae magnitude-redshift data re- vealed a new phenomenon of “dark energy” which, it is claimed, forms 73% of the energy / matter density of the present-epoch universe, and which is linked to the further claim of an accelerating expansion of the universe. In 2011 Perlmutter, Schmidt and Riess received the Nobel Prize in Physics “for the discovery of the accelerating ex- pansion of the Universe through observations of distant supernovae”. Here it is shown that (i a generic model-independent analysis of this data reveals a uniformly expanding universe, (ii their analysis actually used Newtonian gravity, and finally (iii the data, as well as the CMB fluctuation data, does not require “dark energy” nor “dark matter”, but instead reveals the phenomenon of a dynamical space, which is absent from the Friedmann model.

  7. Expanding the knowledge translation metaphor.

    Science.gov (United States)

    Engebretsen, Eivind; Sandset, Tony Joakim; Ødemark, John

    2017-03-13

    Knowledge translation (KT) is a buzzword in modern medical science. However, there has been little theoretical reflection on translation as a process of meaning production in KT. In this paper, we argue that KT will benefit from the incorporation of a more theoretical notion of translation as an entangled material, textual and cultural process. We discuss and challenge fundamental assumptions in KT, drawing on theories of translation from the human sciences. We show that the current construal of KT as separate from and secondary to the original scientific message is close to the now deeply compromised literary view of translation as the simple act of copying the original. Inspired by recent theories of translation, we claim that KT can be more adequately understood in terms of a 'double supplement' - on the one hand, KT offers new approaches to the communication of scientific knowledge to different groups in the healthcare system with the aim of supplementing a lack of knowledge among clinicians (and patients). On the other, it demonstrates that a textual and cultural supplement, namely a concern with target audiences (clinicians and patients), is inevitable in the creation of an 'autonomous' science. Hence, the division between science and its translation is unproductive and impossible to maintain. We discuss some possible implications of our suggested shift in concept by drawing on pharmaceutical interventions for the prevention of HIV as a case. We argue that such interventions are based on a supplementary and paradoxical relation to the target audiences, both presupposing and denying their existence. More sophisticated theories of translation can lay the foundation for an expanded model of KT that incorporates a more adequate and reflective description of the interdependency of scientific, cultural, textual and material practices.

  8. Gene surfing in expanding populations.

    Science.gov (United States)

    Hallatschek, Oskar; Nelson, David R

    2008-02-01

    Large scale genomic surveys are partly motivated by the idea that the neutral genetic variation of a population may be used to reconstruct its migration history. However, our ability to trace back the colonization pathways of a species from their genetic footprints is limited by our understanding of the genetic consequences of a range expansion. Here, we study, by means of simulations and analytical methods, the neutral dynamics of gene frequencies in an asexual population undergoing a continual range expansion in one dimension. During such a colonization period, lineages can fix at the wave front by means of a "surfing" mechanism [Edmonds, C.A., Lillie, A.S., Cavalli-Sforza, L.L., 2004. Mutations arising in the wave front of an expanding population. Proc. Natl. Acad. Sci. 101, 975-979]. We quantify this phenomenon in terms of (i) the spatial distribution of lineages that reach fixation and, closely related, (ii) the continual loss of genetic diversity (heterozygosity) at the wave front, characterizing the approach to fixation. Our stochastic simulations show that an effective population size can be assigned to the wave that controls the (observable) gradient in heterozygosity left behind the colonization process. This effective population size is markedly higher in the presence of cooperation between individuals ("pushed waves") than when individuals proliferate independently ("pulled waves"), and increases only sub-linearly with deme size. To explain these and other findings, we develop a versatile analytical approach, based on the physics of reaction-diffusion systems, that yields simple predictions for any deterministic population dynamics. Our analytical theory compares well with the simulation results for pushed waves, but is less accurate in the case of pulled waves when stochastic fluctuations in the tip of the wave are important.

  9. Expanding the Interaction Equivalency Theorem

    Directory of Open Access Journals (Sweden)

    Brenda Cecilia Padilla Rodriguez

    2015-06-01

    Full Text Available Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner is present at a high level. This study sought to apply this theorem to the corporate sector, and to expand it to include other indicators of course effectiveness: satisfaction, knowledge transfer, business results and return on expectations. A large Mexican organisation participated in this research, with 146 learners, 30 teachers and 3 academic assistants. Three versions of an online course were designed, each emphasising a different type of interaction. Data were collected through surveys, exams, observations, activity logs, think aloud protocols and sales records. All course versions yielded high levels of effectiveness, in terms of satisfaction, learning and return on expectations. Yet, course design did not dictate the types of interactions in which students engaged within the courses. Findings suggest that the interaction equivalency theorem can be reformulated as follows: In corporate settings, an online course can be effective in terms of satisfaction, learning, knowledge transfer, business results and return on expectations, as long as (a at least one of three types of interaction (learner-content, learner-teacher or learner-learner features prominently in the design of the course, and (b course delivery is consistent with the chosen type of interaction. Focusing on only one type of interaction carries a high risk of confusion, disengagement or missed learning opportunities, which can be managed by incorporating other forms of interactions.

  10. Geothermal ORC Systems Using Large Screw Expanders

    OpenAIRE

    Biederman, Tim R.; Brasz, Joost J.

    2014-01-01

    Geothermal ORC Systems using Large Screw Expanders Tim Biederman Cyrq Energy Abstract This paper describes a low-temperature Organic Rankine Cycle Power Recovery system with a screw expander a derivative of developed of Kaishan's line of screw compressors, as its power unit. The screw expander design is a modified version of its existing refrigeration compressor used on water-cooled chillers. Starting the ORC development program with existing refrigeration screw compre...

  11. Expanding/Extending English: Interdisciplinarity and Internationalism.

    Science.gov (United States)

    Fleishman, Avrom

    1994-01-01

    Discusses the recent efforts to expand literary studies into numerous allied fields and the possible effects that such attempts toward interdisciplinarity and internationalism might have. Warns against possible negative consequences of interdisciplinary approaches. Calls for an expanded view of English as a field of study. (HB)

  12. Screw expander for light duty diesel engines

    Science.gov (United States)

    1983-01-01

    Preliminary selection and sizing of a positive displacement screw compressor-expander subsystem for a light-duty adiabatic diesel engine; development of a mathematical model to describe overall efficiencies for the screw compressor and expander; simulation of operation to establish overall efficiency for a range of design parameters and at given engine operating points; simulation to establish potential net power output at light-duty diesel operating points; analytical determination of mass moments of inertia for the rotors and inertia of the compressor-expander subsystem; and preparation of engineering layout drawings of the compressor and expander are discussed. As a result of this work, it was concluded that the screw compressor and expander designed for light-duty diesel engine applications are viable alternatives to turbo-compound systems, with acceptable efficiencies for both units, and only a moderate effect on the transient response.

  13. A-coupled-expanding and distributional chaos

    International Nuclear Information System (INIS)

    Kim, Cholsan; Ju, Hyonhui; Chen, Minghao; Raith, Peter

    2015-01-01

    The concept of A-coupled-expanding maps is one of the more natural and useful ideas generalized from the horseshoe map which is commonly known as a criterion of chaos. It is well known that distributional chaos is one of the concepts which reflect strong chaotic behavior. In this paper, we focus on the relationship between A-coupled-expanding and distributional chaos. We prove two theorems which give sufficient conditions for a strictly A-coupled-expanding map to be distributionally chaotic in the senses of two kinds, where A is an m × m irreducible transition matrix

  14. Helium turbo-expander with an alternator

    International Nuclear Information System (INIS)

    Akiyama, Yoshitane

    1980-01-01

    Study was made on a helium turbo-expander, the heart of helium refrigerator systems, in order to develop a system which satisfies the required conditions. A helium turbo-expander with externally pressurized helium gas bearings at the temperature of liquid nitrogen and an alternator as a brake have been employed. The essential difference between a helium turbo-expander and a nitrogen turbo-expander was clarified. The gas bearing lubricated with nitrogen at room temperature and the gas bearing lubricated with helium at low temperature were tested. The flow rate of helium in a helium refrigerator for a large superconducting magnet is comparatively small, therefore a helium turbine must be small, but the standard for large turbine design can be applied to such small turbine. Using the alternator as a brake, the turbo-expander was easily controllable electrically. The prototype turbo-expander was made, and the liquefaction test with it and MHD power generation test were carried out. (Kako, I.)

  15. Distribution and movement of scalloped hammerhead Sphryna ...

    African Journals Online (AJOL)

    In the Western Cape, Southern Cape and Eastern Cape, few sharks were tagged during the autumn/winter months, whereas in KwaZulu-Natal and Transkei sharks were tagged throughout the year. Large-scale directional movements observed may have been migrations in response to seasonal sea surface temperature ...

  16. The Expanded Large Scale Gap Test

    Science.gov (United States)

    1987-03-01

    NSWC TR 86-32 DTIC THE EXPANDED LARGE SCALE GAP TEST BY T. P. LIDDIARD D. PRICE RESEARCH AND TECHNOLOGY DEPARTMENT ’ ~MARCH 1987 Ap~proved for public...arises, to reduce the spread in the LSGT 50% gap value.) The worst charges, such as those with the highest or lowest densities, the largest re-pressed...Arlington, VA 22217 PE 62314N INS3A 1 RJ14E31 7R4TBK 11 TITLE (Include Security CIlmsilficatiorn The Expanded Large Scale Gap Test . 12. PEIRSONAL AUTHOR() T

  17. Semiclassical expanding discrete space-times

    International Nuclear Information System (INIS)

    Cobb, W.K.; Smalley, L.L.

    1981-01-01

    Given the close ties between general relativity and geometry one might reasonably expect that quantum effects associated with gravitation might also be tied to the geometry of space-time, namely, to some sort of discreteness in space-time itself. In particular it is supposed that space-time consists of a discrete lattice of points rather than the usual continuum. Since astronomical evidence seems to suggest that the universe is expanding, the lattice must also expand. Some of the implications of such a model are that the proton should presently be stable, and the universe should be closed although the mechanism for closure is quantum mechanical. (author)

  18. Theoretical models for recombination in expanding gas

    International Nuclear Information System (INIS)

    Avron, Y.; Kahane, S.

    1978-09-01

    In laser isotope separation of atomic uranium, one is confronted with the theoretical problem of estimating the concentration of thermally ionized uranium atoms. To investigate this problem theoretical models for recombination in an expanding gas and in the absence of local thermal equilibrium have been constructed. The expansion of the gas is described by soluble models of the hydrodynamic equation, and the recombination by rate equations. General results for the freezing effect for the suitable ranges of the gas parameters are obtained. The impossibility of thermal equilibrium in expanding two-component systems is proven

  19. Two Types of Expanding Lie Algebra and New Expanding Integrable Systems

    International Nuclear Information System (INIS)

    Dong Huanhe; Yang Jiming; Wang Hui

    2010-01-01

    From a new Lie algebra proposed by Zhang, two expanding Lie algebras and its corresponding loop algebras are obtained. Two expanding integrable systems are produced with the help of the generalized zero curvature equation. One of them has complex Hamiltion structure with the help of generalized Tu formula (GTM). (general)

  20. Technical Note: Effect of Incorporating Expanded Polystyrene ...

    African Journals Online (AJOL)

    Incorporating expanded polystyrene granules in concrete matrix can produce lightweight polystyrene aggregate concrete of various densities. Workability which is an important property of concrete, aects the rate of placement and the degree of compaction of concrete. Inadequate compaction leads to reduction in both ...

  1. Expanding economic opportunities in protracted displacement

    OpenAIRE

    Miki Takahashi; Michael Moroz; Jonathan Peters; Jason Pronyk; Richard Barltrop

    2018-01-01

    Welcome progress has been made towards realising commitments made by international donors and host country governments to expand economic opportunities for Syrian refugees and host communities in neighbouring countries. However targets and commitments also bring new challenges, and evidence must underpin new policies.

  2. Women Engineering Faculty: Expanding the Pipeline

    Science.gov (United States)

    Greni, Nadene Deiterman

    2006-01-01

    The purpose for this case study was to explore the features of undergraduate engineering departmental and college support that influenced the persistence of women students. Women engineering faculty members were among the participants at three Land Grant universities in the Midwest. The data revealed the theme, Expanding the Pipeline, and…

  3. Custom Ontologies for Expanded Network Analysis

    Science.gov (United States)

    2006-12-01

    for Expanded Network Analysis. In Visualising Network Information (pp. 6-1 – 6-10). Meeting Proceedings RTO-MP-IST-063, Paper 6. Neuilly-sur-Seine...Even to this day, current research groups are working to develop an approach that involves taking all available text, video, imagery and audio and

  4. Expanding Your Horizons Conference in Geneva

    CERN Multimedia

    Chromek-Burckhart, Doris

    2011-01-01

    CERN and its experiments participated in Expanding Your Horizons (EYH) in Science and Mathematics conference in Geneva on 12th November. EYH nurture girls' interest in science and math courses to encourage them to consider careers in science, technology, engineering, and math.

  5. Expanding economic opportunities in protracted displacement

    Directory of Open Access Journals (Sweden)

    Miki Takahashi

    2018-02-01

    Full Text Available Welcome progress has been made towards realising commitments made by international donors and host country governments to expand economic opportunities for Syrian refugees and host communities in neighbouring countries. However targets and commitments also bring new challenges, and evidence must underpin new policies.

  6. Circle diffeomorphisms forced by expanding circle maps

    NARCIS (Netherlands)

    Homburg, A.J.

    2012-01-01

    We discuss the dynamics of skew product maps defined by circle diffeomorphisms forced by expanding circle maps. We construct an open class of such systems that are robustly topologically mixing and for which almost all points in the same fiber converge under iteration. This property follows from the

  7. Expanding the Audience for the Performing Arts.

    Science.gov (United States)

    Andreasen, Alan R.

    Becoming involved in the arts is a process that involves movement through several stages, from disinterest to active attendance at and enthusiasm for performing arts events. Since target consumers at any time will differ in their placement on this continuum, marketing programs to expand arts audiences must first identify where each target segment…

  8. Expanded austenite, crystallography and residual stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2010-01-01

    The identity of expanded austenite as developing during low temperature nitriding and/or carburising of austenitic stainless steel has been under debate since the very first observation of this phase. In the present article, recent results obtained with (a) homogeneous samples of various uniform ...

  9. Expanded austenite; crystallography and residual stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2009-01-01

    The identity of expanded austenite as developing during low temperature nitriding and/or carburizing of austenitic stainless steel has been under debate since the very first observation of this phase. In the present article recent results obtained with i) homogeneous samples of various uniform co...

  10. Expanding Greenland’s Glacial Record

    DEFF Research Database (Denmark)

    Bjørk, Anders Anker

    . On order to expand the glacial history of Greenland, this thesis explores physical and geological archives for evidence of the glaciers’ past response to climatic variations. Using aerial photographs, the dynamic history of the Greenland Ice Sheet is extended back to 1900 C.E. Glacier changes covering...

  11. An Expanding Universe in the Classroom.

    Science.gov (United States)

    Chandler, David

    1991-01-01

    Two computer-generated star charts that can be used as overlay transparencies to show an expanding universe are presented. Directions on how to use the star charts to determine the Hubble constant and the age of the universe are provided. (KR)

  12. Hubble, Hubble's Law and the Expanding Universe

    Indian Academy of Sciences (India)

    Srimath

    H ubble's nam e is associated closely w ith the idea of an expanding universe as he discovered the relation between the recession velocity and the distances of galaxies. H ubble also did a lot of pioneering w ork on the distribution of galaxies in the universe. In this article we take a look at H ubble's law and discuss how it ...

  13. Expanding CEP290 mutational spectrum in ciliopathies

    NARCIS (Netherlands)

    Travaglini, Lorena; Brancati, Francesco; Attie-Bitach, Tania; Audollent, Sophie; Bertini, Enrico; Kaplan, Josseline; Perrault, Isabelle; Iannicelli, Miriam; Mancuso, Brunella; Rigoli, Luciana; Rozet, Jean-Michel; Swistun, Dominika; Tolentino, Jerlyn; Dallapiccola, Bruno; Gleeson, Joseph G.; Valente, Enza Maria; Zankl, A.; Leventer, R.; Grattan-Smith, P.; Janecke, A.; D'Hooghe, M.; Sznajer, Y.; van Coster, R.; Demerleir, L.; Dias, K.; Moco, C.; Moreira, A.; Kim, C. Ae; Maegawa, G.; Petkovic, D.; Abdel-Salam, G. M. H.; Abdel-Aleem, A.; Zaki, M. S.; Marti, I.; Quijano-Roy, S.; Sigaudy, S.; de Lonlay, P.; Romano, S.; Touraine, R.; Koenig, M.; Lagier-Tourenne, C.; Messer, J.; Collignon, P.; Wolf, N.; Philippi, H.; Kitsiou Tzeli, S.; Halldorsson, S.; Johannsdottir, J.; Ludvigsson, P.; Phadke, S. R.; Udani, V.; Stuart, B.; Magee, A.; Lev, D.; Michelson, M.; Ben-Zeev, B.; Fischetto, R.; Benedicenti, F.; Stanzial, F.; Borgatti, R.; Accorsi, P.; Battaglia, S.; Fazzi, E.; Giordano, L.; Pinelli, L.; Boccone, L.; Bigoni, S.; Ferlini, A.; Donati, M. A.; Caridi, G.; Divizia, M. T.; Faravelli, F.; Ghiggeri, G.; Pessagno, A.; Briguglio, M.; Briuglia, S.; Salpietro, C. D.; Tortorella, G.; Adami, A.; Castorina, P.; Lalatta, F.; Marra, G.; Riva, D.; Scelsa, B.; Spaccini, L.; Uziel, G.; del Giudice, E.; Laverda, A. M.; Ludwig, K.; Permunian, A.; Suppiej, A.; Signorini, S.; Uggetti, C.; Battini, R.; Di Giacomo, M.; Cilio, M. R.; Di Sabato, M. L.; Leuzzi, V.; Parisi, P.; Pollazzon, M.; Silengo, M.; de Vescovi, R.; Greco, D.; Romano, C.; Cazzagon, M.; Simonati, A.; Al-Tawari, A. A.; Bastaki, L.; Mégarbané, A.; Sabolic Avramovska, V.; de Jong, M. M.; Stromme, P.; Koul, R.; Rajab, A.; Azam, M.; Barbot, C.; Martorell Sampol, L.; Rodriguez, B.; Pascual-Castroviejo, I.; Teber, S.; Anlar, B.; Comu, S.; Karaca, E.; Kayserili, H.; Yüksel, A.; Akcakus, M.; Al Gazali, L.; Sztriha, L.; Nicholl, D.; Woods, C. G.; Bennett, C.; Hurst, J.; Sheridan, E.; Barnicoat, A.; Hennekam, R.; Lees, M.; Blair, E.; Bernes, S.; Sanchez, H.; Clark, A. E.; DeMarco, E.; Donahue, C.; Sherr, E.; Hahn, J.; Sanger, T. D.; Gallager, T. E.; Dobyns, W. B.; Daugherty, C.; Krishnamoorthy, K. S.; Sarco, D.; Walsh, C. A.; McKanna, T.; Milisa, J.; Chung, W. K.; de Vivo, D. C.; Raynes, H.; Schubert, R.; Seward, A.; Brooks, D. G.; Goldstein, A.; Caldwell, J.; Finsecke, E.; Maria, B. L.; Holden, K.; Cruse, R. P.; Swoboda, K. J.; Viskochil, D.

    2009-01-01

    Ciliopathies are an expanding group of rare conditions characterized by multiorgan involvement, that are caused by mutations in genes encoding for proteins of the primary cilium or its apparatus. Among these genes, CEP290 bears an intriguing allelic spectrum, being commonly mutated in Joubert

  14. Expanding CTE Opportunities through Blended Learning

    Science.gov (United States)

    McKinstry, Elizabeth

    2012-01-01

    The global economy, 21st century skills, knowledge society, college and career readiness, digital and project-based learning are all common terms to educators who are expanding their learning environments beyond the classroom to meet the needs of all students. It is common knowledge that the rapid technological advances of this century have…

  15. Bank Directors’ Perceptions of Expanded Auditor's Reports

    DEFF Research Database (Denmark)

    Boolaky, Pran Krishansing; Quick, Reiner

    2016-01-01

    Subsequent to the financial crisis, standard setters developed suggestions for enhancing the audit function, in order to increase financial stability. One related idea is to expand the audit report disclosed to the public, to ensure that it is fit for purpose. This study investigates the impact o...

  16. Refrigeration generation using expander-generator units

    Science.gov (United States)

    Klimenko, A. V.; Agababov, V. S.; Koryagin, A. V.; Baidakova, Yu. O.

    2016-05-01

    The problems of using the expander-generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander-generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration-carrier being cooled. The conclusion was made that the expander-generator units can be used to create trigeneration plants both at major power plants and at small energy.

  17. Expanding Advanced Civilizations in the Universe

    Science.gov (United States)

    Gros, C.

    The 1950 lunch-table remark by Enrico Fermi `Where is everybody' has started intensive scientific and philosophical discussions about what we call nowadays the `Fermi paradox': If there had been ever a single advanced civilization in the cosmological history of our galaxy, dedicated to expansion, it would have had plenty of time to colonize the entire galaxy via exponential growth. No evidence of present or past alien visits to earth are known to us, leading to the standard conclusion that no advanced expanding civilization has ever existed in the milky-way. This conclusion rest fundamentally on the ad-hoc assumption, that any alien civilizations dedicated to expansion at one time would remain dedicated to expansions forever. Considering our limited knowledge about alien civilizations we need however to relax this basic assumption. Here we show that a substantial and stable population of expanding advanced civilization might consequently exist in our galaxy.

  18. Black holes in an expanding universe.

    Science.gov (United States)

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-02

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 < or = for all w < or = 1). It is an exact solution of the Einstein-scalar-Maxwell system, in which we have two Maxwell-type U(1) fields coupled to the scalar field. The potential of the scalar field is an exponential. We find a regular horizon, which depends on one parameter [the ratio of the energy density of U(1) fields to that of the scalar field]. The horizon is static because of the balance on the horizon between gravitational attractive force and U(1) repulsive force acting on the scalar field. We also calculate the black hole temperature.

  19. Parameter estimation for an expanding universe

    Directory of Open Access Journals (Sweden)

    Jieci Wang

    2015-03-01

    Full Text Available We study the parameter estimation for excitations of Dirac fields in the expanding Robertson–Walker universe. We employ quantum metrology techniques to demonstrate the possibility for high precision estimation for the volume rate of the expanding universe. We show that the optimal precision of the estimation depends sensitively on the dimensionless mass m˜ and dimensionless momentum k˜ of the Dirac particles. The optimal precision for the ratio estimation peaks at some finite dimensionless mass m˜ and momentum k˜. We find that the precision of the estimation can be improved by choosing the probe state as an eigenvector of the hamiltonian. This occurs because the largest quantum Fisher information is obtained by performing projective measurements implemented by the projectors onto the eigenvectors of specific probe states.

  20. Gravitational instability in a multicomponent expanding medium

    International Nuclear Information System (INIS)

    Solov'eva, L.V.; Nurgaliev, I.S.

    1985-01-01

    In the Newtonian approximation we consider the gravitational instability of a two- or N-component medium in an expanding universe. The system of density-perturbation equations is solved in the short- and long-wave limits. For small values of the wave vector k, a result obtained for the stationary case continues to hold true: at most there can exist only one unstable mode. If k is kept fixed, the introduction of a perturbation component delta/sub i/ will speed the growth of fluctuations delta/sub j/, provided the adiabatic indices γ/sub i/>γ/sub j/. In the large-k limit, ordinary acoustic waves result. Other components will begin to manifest themselves in the first-order terms when the oscillation amplitude is expanded in powers of k -1 : provided γ/sub j/>γ/sub i/> or =4/3, the ith-component amplitude will decay more slowly than otherwise

  1. Expander graphs in pure and applied mathematics

    OpenAIRE

    Lubotzky, Alexander

    2012-01-01

    Expander graphs are highly connected sparse finite graphs. They play an important role in computer science as basic building blocks for network constructions, error correcting codes, algorithms and more. In recent years they have started to play an increasing role also in pure mathematics: number theory, group theory, geometry and more. This expository article describes their constructions and various applications in pure and applied mathematics.

  2. GWDC Expands High-End Market Share

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ It is a decision of great significance for GWDC to expand high-end market share in order to realize its transformation of development strategy and improve its development quality. As an important step of GWDC to explore high-end market, Oman PDO Project marks the first time that the Chinese petroleum engineering service team cooperates with the transnational petroleum corporations ranking first three in the world.

  3. Carbohydrate plasma expanders for passive tumor targeting

    DEFF Research Database (Denmark)

    Hoffmann, Stefan; Caysa, Henrike; Kuntsche, Judith

    2013-01-01

    The objective of this study was to investigate the suitability of carbohydrate plasma volume expanders as a novel polymer platform for tumor targeting. Many synthetic polymers have already been synthesized for targeted tumor therapy, but potential advantages of these carbohydrates include inexpen...... was characterized in human colon carcinoma xenograft bearing nude mice. A tumor specific accumulation of HES 450 was observed, which proves it’s potential as carrier for passive tumor targeting....

  4. Short wavelength striations on expanding plasma clouds

    International Nuclear Information System (INIS)

    Winske, D.; Gary, S.P.

    1989-01-01

    The growth and evolution of short wavelength (< ion gyroradius) flute modes on a plasma expanding across an ambient magnetic field have been actively studied in recent years, both by means of experiments in the laboratory as well as in space and through numerical simulations. We review the relevant observations and simulations results, discuss the instability mechanism and related linear theory, and describe recent work to bring experiments and theory into better agreement. 30 refs., 6 figs

  5. Inextendibility of expanding cosmological models with symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Dafermos, Mihalis [University of Cambridge, Department of Pure Mathematics and Mathematical Statistics, Wilberforce Road, Cambridge CB3 0WB (United Kingdom); Rendall, Alan D [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muehlenberg 1, D-14476 Golm (Germany)

    2005-12-07

    A new criterion for inextendibility of expanding cosmological models with symmetry is presented. It is applied to derive a number of new results and to simplify the proofs of existing ones. In particular, it shows that the solutions of the Einstein-Vlasov system with T{sup 2} symmetry, including the vacuum solutions, are inextendible in the future. The technique introduced adds a qualitatively new element to the available tool-kit for studying strong cosmic censorship. (letter to the editor)

  6. Intermittency Statistics in the Expanding Solar Wind

    Science.gov (United States)

    Cuesta, M. E.; Parashar, T. N.; Matthaeus, W. H.

    2017-12-01

    The solar wind is observed to be turbulent. One of the open questions in solar wind research is how the turbulence evolves as the solar wind expands to great distances. Some studies have focused on evolution of the outer scale but not much has been done to understand how intermittency evolves in the expanding wind beyond 1 AU (see [1,2]). We use magnetic field data from Voyager I spacecraft from 1 to 10AU to study the evolution of statistics of magnetic discontinuities. We perform various statistical tests on these discontinuities and make connections to the physical processes occurring in the expanding wind.[1] Tsurutani, Bruce T., and Edward J. Smith. "Interplanetary discontinuities: Temporal variations and the radial gradient from 1 to 8.5 AU." Journal of Geophysical Research: Space Physics 84.A6 (1979): 2773-2787.[2] Greco, A., et al. "Evidence for nonlinear development of magnetohydrodynamic scale intermittency in the inner heliosphere." The Astrophysical Journal 749.2 (2012): 105.

  7. Emergence of oscillons in an expanding background

    International Nuclear Information System (INIS)

    Farhi, E.; Guth, A. H.; Iqbal, N.; Graham, N.; Rosales, R. R.; Stamatopoulos, N.

    2008-01-01

    We consider a (1+1) dimensional scalar field theory that supports oscillons, which are localized, oscillatory, stable solutions to nonlinear equations of motion. We study this theory in an expanding background and show that oscillons now lose energy, but at a rate that is exponentially small when the expansion rate is slow. We also show numerically that a universe that starts with (almost) thermal initial conditions will cool to a final state where a significant fraction of the energy of the universe--on the order of 50%--is stored in oscillons. If this phenomenon persists in realistic models, oscillons may have cosmological consequences.

  8. Expanding the Bethe/Gauge dictionary

    Science.gov (United States)

    Bullimore, Mathew; Kim, Hee-Cheol; Lukowski, Tomasz

    2017-11-01

    We expand the Bethe/Gauge dictionary between the XXX Heisenberg spin chain and 2d N = (2, 2) supersymmetric gauge theories to include aspects of the algebraic Bethe ansatz. We construct the wave functions of off-shell Bethe states as orbifold defects in the A-twisted supersymmetric gauge theory and study their correlation functions. We also present an alternative description of off-shell Bethe states as boundary conditions in an effective N = 4 supersymmetric quantum mechanics. Finally, we interpret spin chain R-matrices as correlation functions of Janus interfaces for mass parameters in the supersymmetric quantum mechanics.

  9. Angular momentum conservation for uniformly expanding flows

    International Nuclear Information System (INIS)

    Hayward, Sean A

    2007-01-01

    Angular momentum has recently been defined as a surface integral involving an axial vector and a twist 1-form, which measures the twisting around the spacetime due to a rotating mass. The axial vector is chosen to be a transverse, divergence-free, coordinate vector, which is compatible with any initial choice of axis and integral curves. Then a conservation equation expresses the rate of the change of angular momentum along a uniformly expanding flow as a surface integral of angular momentum densities, with the same form as the standard equation for an axial Killing vector, apart from the inclusion of an effective energy tensor for gravitational radiation

  10. Expandable tubulars for use in geologic structures

    Science.gov (United States)

    Spray, Jeffery A.; Svedeman, Steven; Walter, David; Mckeighan, Peter; Siebanaler, Shane; Dewhurst, Peter; Hobson, Steven; Foss, Doug; Wirz, Holger; Sharpe, Aaron; Apostal, Michael

    2014-08-12

    An expandable tubular includes a plurality of leaves formed from sheet material that have curved surfaces. The leaves extend around a portion or fully around the diameter of the tubular structure. Some of the adjacent leaves of the tubular are coupled together. The tubular is compressed to a smaller diameter so that it can be inserted through previously deployed tubular assemblies. Once the tubular is properly positioned, it is deployed and coupled or not coupled to a previously deployed tubular assembly. The tubular is useful for all types of wells and boreholes.

  11. Expanding Technological Frames Towards Mediated Collaboration

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Scupola, Ada; Fitzgerald, Brian

    2006-01-01

    This paper provides an in-depth analysis of technological and social factors leading to the successful adoption of groupware in a virtual team in educational setting. Drawing on a theoretical framework based on the concept of technological frames, we conducted an action research study to analyze...... the chronological sequence of events leading to groupware adoption. We argue that groupware adoption can be conceptualized as a three-step process of expanding and aligning individual technological frames towards groupware: The first step comprises activities facilitating participants in articulation and evaluation...... collaborative practice and use of technology, and that this activity cannot take place at the outset....

  12. Endotracheal expandable metallic stent placement in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, S; Tanabe, Y; Fujiwara, Y; Koyama, T; Tanigawa, N; Kobayashi, M; Katsube, Y; Nakamura, H [Tottori Univ. School of Medicine, Yonago (Japan). Dept. of Radiology Research Inst. for Microbial Diseases, Osaka (Japan). Dept. of Radiology

    1991-01-01

    Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. These stents were constructed of 0.45, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface. (orig.).

  13. [Treatment of tracheobronchomalacia with expandable metallic stents].

    Science.gov (United States)

    Antón-Pacheco Sánchez, J; García Vázquez, A; Cuadros García, J; Cano Novillo, I; Villafruela Sanz, M; Berchi García, F J

    2002-10-01

    Tracheomalacia is an unfrequent disease that causes tracheal collapse during breathing. It is generally associated to esophageal atresia, but cases of primary tracheomalacia and others secondary to extrinsic compression, have also been described. Spontaneous resolution is generally the rule and only a few cases need surgical treatment. When this therapy fails or is not indicated for any reason, endoluminal tracheobronchial stents may be used. We have treated two patients with four expandable metallic stents: one had severe tracheomalacia associated to esophageal atresia and the other tracheobronchomalacia secondary to cardiomegaly. Results have been good in both cases.

  14. Multiparticle dynamics in an expanding universe

    Science.gov (United States)

    Anderson, James L.

    1995-11-01

    Approximate equations of motion for multiparticle systems in an expanding Einstein-deSitter universe are derived from the Einstein-Maxwell field equations using the Einstein-Infeld-Hoffmann surface integral method. At the Newtonian level of approximation one finds that, in comoving coordinates, both the Newtonian gravitational and Coulomb interactions in these equations are multiplied by the inverse third power of the scale factor R(t) appearing in the Einstein-deSitter field and they acquire a cosmic ``drag'' term. Nevertheless, both the period and luminosity size of bound two-body systems whose period is small compared to the Hubble time are found to be independent of t.

  15. Gravitational mass in an expanding universe

    International Nuclear Information System (INIS)

    Sannan, S.

    1986-01-01

    A test for the Hawking definition of mass is given in a Tolman--Bondi model that asymptotically approaches the open Friedmann universe. An expanding universe filled with dustlike matter of zero pressure is considered. The matter distribution is spherically symmetric but nonhomogeneous. With appropriate boundary conditions, the calculation yields a finite and nonzero value for the Hawking mass, measured as a deviation from a ''renormalized'' zero mass in the unperturbed Friedmann model. These boundary conditions are more restrictive than those found for a model with gravitational radiation

  16. Expandable antivibration bar for a steam generator

    International Nuclear Information System (INIS)

    Lagally, H.O.

    1986-01-01

    A steam generator tube support structure comprises expandable antivibration bars positioned between rows of tubes in the steam generator and attached to retaining rings surrounding the bundle of tubes. The antivibration bars have adjacent bar sections with mating surfaces formed as inclined planes which upon relative longitudinal motion between the upper and lower bars provides a means to increase the overall thickness across the structure to the required value. The bar section is retained against longitudinal movement in take-up assembly whereas the bar section is movable longitudinally by rotation of a nut. (author)

  17. Comparison of self-expandable and balloon-expanding stents for hybrid ductal stenting in hypoplastic left heart complex.

    Science.gov (United States)

    Goreczny, Sebastian; Qureshi, Shakeel A; Rosenthal, Eric; Krasemann, Thomas; Nassar, Mohamed S; Anderson, David R; Morgan, Gareth J

    2017-07-01

    We aimed to compare the procedural and mid-term performance of a specifically designed self-expanding stent with balloon-expandable stents in patients undergoing hybrid palliation for hypoplastic left heart syndrome and its variants. The lack of specifically designed stents has led to off-label use of coronary, biliary, or peripheral stents in the neonatal ductus arteriosus. Recently, a self-expanding stent, specifically designed for use in hypoplastic left heart syndrome, has become available. We carried out a retrospective cohort comparison of 69 neonates who underwent hybrid ductal stenting with balloon-expandable and self-expanding stents from December, 2005 to July, 2014. In total, 43 balloon-expandable stents were implanted in 41 neonates and more recently 47 self-expanding stents in 28 neonates. In the balloon-expandable stents group, stent-related complications occurred in nine patients (22%), compared with one patient in the self-expanding stent group (4%). During follow-up, percutaneous re-intervention related to the ductal stent was performed in five patients (17%) in the balloon-expandable stent group and seven patients (28%) in self-expanding stents group. Hybrid ductal stenting with self-expanding stents produced favourable results when compared with the results obtained with balloon-expandable stents. Immediate additional interventions and follow-up re-interventions were similar in both groups with complications more common in those with balloon-expandable stents.

  18. Expanded Endoscopic Endonasal Resection of Retrochiasmatic Craniopharyngioma.

    Science.gov (United States)

    Davanzo, Justin R; Goyal, Neerav; Zacharia, Brad E

    2018-02-01

    This video abstract demonstrates the use of the expanded endoscopic endonasal approach for the resection of a retrochiasmatic craniopharyngioma. These tumors are notoriously difficult to treat, and many approaches have been tried to facilitate safe and effective resection. The endoscopic endonasal approach has been increasingly utilized for selected sellar/suprasellar pathology. We present the case of a 39-year-old man who was found to have a cystic, partially calcified suprasellar mass consistent with a craniopharyngioma. To facilitate robust skull base repair, a vascularized nasoseptal flap was harvested. A wide sphenoidotomy was performed and the sella and tuberculum were exposed. After the dural opening and arachnoid dissection, the stalk was identified, merging seamlessly with the tumor capsule. The lesion was then internally debulked with the use of an ultrasonic aspirator. The capsule was then dissected off of the optic chiasm, thalamus, and hypothalamus. The cavity was inspected with an angled endoscope to ensure complete resection. A multilayered reconstruction was performed using autologous fascia lata, the previously harvested nasoseptal flap, and dural sealant. Postoperatively, the patient did have expected panhypopituitarism but remained neurologically intact and had improvement in his vision. In conclusion, this video demonstrates how an expanded endonasal approach can be used to safely resect a craniopharyngioma, even when in close proximity to delicate structures such as the optic chiasm. The link to the video can be found at: https://youtu.be/tahjHmrXhc4 .

  19. Hybrid Scenarios, Transmedia Storytelling, Expanded Ethnography

    Directory of Open Access Journals (Sweden)

    Daniel Domínguez Figaredo

    2012-10-01

    Full Text Available The transformation of social scenarios due to the impact of digital technologies, introduces new possibilities for ethnographic research. Once the initial approaches focused on the dichotomy of “physical-virtual spaces” have been overcame, it comes a stage of maturity that allows the ethnographers to open new avenues for conceptual and analytical methodology applied in techno-social scenarios. This article discusses the evolution of some key dimensions of ethnography according to the new social and epistemological framework. The discussion is based on the analysis of expanded practices that take place in the new techno-social spaces, defined as hybrid environments, where technologies are embedded in the physical life of the subjects. On the one hand, we consider the production of actions based on the assembly of ideas, meanings and objects through digital mediation devices. It is also analysed the transmedia component of the narratives that make sense to allow the experiments. Underlying the analysis, some elements are introduced for discussion on the scope of expanded ethnographic research, the influence of transmedia phenomenon in the notion of “field” and the methods for determining the significance through digital storytelling.

  20. Electromagnetic fields in an expanding universe

    International Nuclear Information System (INIS)

    Hogan, P.A.; Ellis, G.F.R.

    1989-01-01

    The asymptotic form of the electromagnetic field due to a bounded distribution of charge current in an open, expanding Friedmann--Lemaitre--Robertson--Walker universe is studied. The technique used is to first describe a mechanism for passing from a solution of Maxwell's vacuum field equations on Minkowskian space-time to a solution of Maxwell's field equations in a region free of charge current on the cosmological background. This is tested on the field of an accelerating point charge and then applied to the rigorous treatment of the asymptotic electromagnetic field of a bounded charge-current distribution in Minkowskian space-time given by Goldberg and Kerr [J. Math. Phys. 5, 172 (1964)]. A ''peeling expansion'' of the electromagnetic field in the expanding universe is obtained in inverse powers of a parameter that is proportional to the area distance along the generators of future null cones with vertices on the world line of a fundamental observer. The algebraic character of the two leading coefficients in the expansion is the same as that of the two leading coefficients in the Goldberg--Kerr expansion in Minkowskian space-time. In addition, bounds can be calculated, at any instant in the history of a fundamental observer, on all the coefficients in the peeling expansion, as a consequence of the evaluation of such bounds by Goldberg and Kerr in the case treated by them

  1. Chinese IP expands with self-reliance.

    Science.gov (United States)

    1999-05-01

    In 1999, program officers from JOICFP visited five of 10 projects where JOICFP has provided direct assistance during 1993-95 to enhance health education in China's integrated family planning, maternal-child health programs. The JOICFP team and three members of the Chinese National Steering Committee of the Integrated Projects visited project areas in remote and mountainous areas that are characterized by underdevelopment, low income rates, low rates of hospital deliveries, and high rates of parasitic infection. The monitoring team found that all project areas continued the projects after completion of the 3-year period and even expanded efforts to cover other areas. By 1998, more than a million people had been served, which is quadruple the initial target number. The team found that the program could benefit from additional assistance in training new staff to interact with the public and to use IEC (information, education, communication) materials appropriately. One project area, Shaowu City, opened a new Family Health Service Center in August 1998 with a grant from the Japanese Grant Assistance for Grassroots Projects and assistance from its provincial and local government. This Center serves women and children and adolescents on a fee-charged basis and hopes to expand its service area.

  2. Magnetic fields in an expanding universe

    International Nuclear Information System (INIS)

    Kastor, David; Traschen, Jennie

    2014-01-01

    We find a solution to 4D Einstein–Maxwell theory coupled to a massless dilaton field, for all values of the dilaton coupling, describing a Melvin magnetic field in an expanding universe with ‘stiff matter’ equation of state parameter w = +1. As the universe expands, magnetic flux becomes more concentrated around the symmetry axis for dilaton coupling a<1/√3 and more dispersed for a>1/√3. An electric field circulates around the symmetry axis in the direction determined by Lenz's law. For a = 0 the magnetic flux through a disc of fixed comoving radius is proportional to the proper area of the disc. This result disagrees with the usual expectation based on a test magnetic field that this flux should be constant, and we show why this difference arises. We also find a Melvin solution in an accelerating universe with w = −7/9 for a dilaton field with a certain exponential potential. (paper)

  3. Historical Notes on the Expanding Universe

    Science.gov (United States)

    Way, Michael J.; Belenkyi, Ari; Nussbaumer, Harry; Peacock, John

    2014-01-01

    The article Measuring the Hubble constant by Mario Livio and Adam Riess (Physics Today, October 2013, page 41) reviewed studies of the expanding universe from the 1920s to the present. Although the history of the subject underwent considerable compression to fit the length of a magazine article, we think it may leave a misleading impression of some of the key steps to our current understanding. We therefore offer the following clarifications. Most significantly, papers by Arthur Eddington and by Willem de Sitter in 1930, who successfully promoted Georges Lematres 1927 article for the Scientific Society of Brussels, effected a paradigm shift in interpretation of extragalactic redshifts in 1930. Before then, the astronomical community was generally unaware of the existence of nonstatic cosmological solutions and did not broadly appreciate that redshifts could be thought of locally as Doppler shifts in an expanding matter distribution. Certainly, in 1929 Edwin Hubble referred only to the de Sitter solution of 1917. At the time, the relation between distance and redshift predicted in that model was generally seen purely as a manifestation of static spacetime curvature.

  4. Expanded newborn screening: social and ethical issues.

    Science.gov (United States)

    Dhondt, Jean-Louis

    2010-10-01

    Newborn screening and genetic testing have expanded rapidly in the last decade with the advent of multiplex (e.g., tandem mass spectrometry) and/or DNA technologies. However, screening panels include a large number of disorders, which may not meet all of the traditional screening criteria, established in late 1960s, and used for years to justify screening programs. After a period of expansion driven by technological advances, many reports have reconsidered the justification of expanded programs. Many factors have contributed to test-panel discrepancies between countries. The test-panel review methodology, the way health benefits are weighed against harms, and the socioeconomic-political environment all play a role. Expansion of screening also requires reconsideration of the infrastructure (ideally, in the context of national plans for rare diseases) to support testing, counselling, education, treatment, and follow-up. Consequently, economic aspects cannot be ignored and can be a limitation for expansion. New ethical questions have emerged: risks of discrimination or stigmatization, respect of the autonomy of persons to make decisions, parental anxiety resulting from a false positive test (especially when reporting to parents screening results for untreatable conditions identified as by-products of screening), etc. For disorders where there is not yet confirmation of benefit, it may be prudent to recommend pilot screening and to have a mechanism that can be used to adapt or even to stop a program.

  5. A Rapidly Expanding Bose-Einstein Condensate: An Expanding Universe in the Lab

    Science.gov (United States)

    Eckel, S.; Kumar, A.; Jacobson, T.; Spielman, I. B.; Campbell, G. K.

    2018-04-01

    We study the dynamics of a supersonically expanding, ring-shaped Bose-Einstein condensate both experimentally and theoretically. The expansion redshifts long-wavelength excitations, as in an expanding universe. After expansion, energy in the radial mode leads to the production of bulk topological excitations—solitons and vortices—driving the production of a large number of azimuthal phonons and, at late times, causing stochastic persistent currents. These complex nonlinear dynamics, fueled by the energy stored coherently in one mode, are reminiscent of a type of "preheating" that may have taken place at the end of inflation.

  6. A Rapidly Expanding Bose-Einstein Condensate: An Expanding Universe in the Lab

    Directory of Open Access Journals (Sweden)

    S. Eckel

    2018-04-01

    Full Text Available We study the dynamics of a supersonically expanding, ring-shaped Bose-Einstein condensate both experimentally and theoretically. The expansion redshifts long-wavelength excitations, as in an expanding universe. After expansion, energy in the radial mode leads to the production of bulk topological excitations—solitons and vortices—driving the production of a large number of azimuthal phonons and, at late times, causing stochastic persistent currents. These complex nonlinear dynamics, fueled by the energy stored coherently in one mode, are reminiscent of a type of “preheating” that may have taken place at the end of inflation.

  7. First order phase transition of expanding matter and its fragmentation

    International Nuclear Information System (INIS)

    Chikazumi, Shinpei; Iwamoto, Akira

    2002-01-01

    Using an expanding matter model with a Lennard-Jones potential, the instability of the expanding system is investigated. The pressure, the temperature, and the density fluctuations are calculated as functions of density during the time evolution of the expanding matter, which are compared to the coexistence curve calculated by the Gibbs ensemble. The expanding matter undergoes the first order phase transition in the limit of the quasistatic expansion. The resultant fragment mass distributions are also investigated. (author)

  8. The Expanding Marketplace for Applied Geophysics

    Science.gov (United States)

    Carlson, N.; Sirles, P.

    2012-12-01

    While the image of geophysics for the proverbial "layman" often seems limited to volcanoes and earthquakes, and to the geoscientist this image enlarges to include oil or minerals exploration and whole earth studies, there has been a steady increase in the application of geophysics into the realm of "daily life", such as real estate deals, highway infrastructure, and flood protection. This expansion of applications can be attributed to the improved economics from advances in equipment and interpretation. Traditional geophysical methods that at one time often only fit within the budgets of oil, gas, and minerals exploration programs can now be economically applied to much smaller scale needs like contaminant mapping, landfill delineation, and levee investigations. A real-world, economic example of this expanding marketplace is our company, which began very small and was aimed almost exclusively at the minerals exploration market. Most of our growth has been in the last 10 years, when we have expanded to five offices and a staff with almost 40 geoscientist degrees (21 in geophysics); much of this growth has been in the non-oil, non-minerals arenas. While much of our work still includes minerals exploration, other projects this year include wind-farm foundation studies, cavity detection above underground nuclear tests, landfill studies, acid mine drainage problems, and leaks in evaporation ponds. A methodology example of this expanding market is the induced polarization (IP) survey, once primarily used for minerals exploration, particularly large porphyry copper deposits, but now efficient enough to also use in environmental studies. The IP method has been particularly useful in delineating and characterizing old, poorly documented landfills, and recent research suggests it may also be useful in monitoring the accelerated biodegradation processes used in some cases to rehabilitate the sites. Compared to temperature monitoring systems, IP may be more useful in providing

  9. Gravitational wave memory in an expanding universe

    Science.gov (United States)

    Tolish, Alexander; Wald, Robert

    2016-03-01

    We investigate the gravitational wave memory effect in an expanding FLRW spacetime. We find that if the gravitational field is decomposed into gauge-invariant scalar, vector, and tensor modes after the fashion of Bardeen, only the tensor mode gives rise to memory, and this memory can be calculated using the retarded Green's function associated with the tensor wave equation. If locally similar radiation source events occur on flat and FLRW backgrounds, we find that the resulting memories will differ only by a redshift factor, and we explore whether or not this factor depends on the expansion history of the FLRW universe. We compare our results to related work by Bieri, Garfinkle, and Yau.

  10. The Expanded Very Large Array Project

    Science.gov (United States)

    Perley, Rick

    2012-10-01

    The Expanded Very Large Array Project, begun in 2001, is now completed -- on time, on budget, and ``on spec.'' The major goal of the project was to multiply the key observational capabilities of the Very Large Array -- the world's most powerful, versatile, and productive radio telescope -- by a factor of at least an order of magnitude by implementation of modern technologies. The result of the project is an operationally new telescope -- renamed the Jansky Very Large Array -- which is capable of new science unimagined in 1980, when the original VLA was completed. In this talk, I will review the goals of the project, and describe the new capabilities of the Jansky Very Large Array. Already, the array is providing fabulous new insights into the physics of the universe,and I will spend the majority of the time describing examples of new results.

  11. Ultrasonic velocity measurements in expanded liquid mercury

    International Nuclear Information System (INIS)

    Suzuki, K.; Inutake, M.; Fujiwaka, S.

    1977-10-01

    In this paper we present the first results of the sound velocity measurements in expanded liquid mercury. The measurements were made at temperatures up to 1600 0 C and pressures up to 1700 kg/cm 2 by means of an ultrasonic pulse transmission/echo technique which was newly developed for such high temperature/pressure condition. When the density is larger than 9 g/cm 3 , the observed sound velocity decreases linearly with decreasing density. At densities smaller than 9 g/cm 3 , the linear dependence on the density is no longer observed. The observed sound velocity approaches a minimum near the liquid-gas critical point (rho sub(cr) asymptotically equals 5.5 g/cm 3 ). The existing theories for sound velocity in liquid metals fail to explain the observed results. (auth.)

  12. Fabrication process of expanded cooling jackets

    International Nuclear Information System (INIS)

    Weber, C.M.

    1980-01-01

    The present invention concerns the fabrication process of heat exchangers and in particular, the fabrication and assembly process of cooling jackets of the system driving the control rods used in nuclear reactors. The cooling jackets are assembled for cooling the stator of a tubular motor displacing the control rods. The fabrication and assembling of the cooling jacket is made up by the following operations: - a sleeve has an inner fluid inlet and outlet ways, - an external socket is fitted to the sleeve, - on the external socket a continuous welding is realized, which join the socket to the sleeve, and define a serie of parallel welded turns, - a pressure is established between the sleeve and the socket by a fluid through the outlet or inlet ways of the sleeve. When the other way is sealed up, the socket expands between the welded turns, and the fluid can pass through the jacket [fr

  13. Expanding forensic science through forensic intelligence.

    Science.gov (United States)

    Ribaux, Olivier; Talbot Wright, Benjamin

    2014-12-01

    Research and Development ('R&D') in forensic science currently focuses on innovative technologies improving the efficiency of existing forensic processes, from the detection of marks and traces at the scene, to their presentation in Court. R&D approached from this perspective provides no response to doubts raised by recent criminological studies, which question the effective contribution of forensic science to crime reduction, and to policing in general. Traces (i.e. forensic case data), as remnants of criminal activity are collected and used in various forms of crime monitoring and investigation. The aforementioned doubts therefore need to be addressed by expressing how information is conveyed by traces in these processes. Modelling from this standpoint expands the scope of forensic science and provides new R&D opportunities. Twelve propositions for R&D are stated in order to pave the way. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  14. The law and the expanding nursing role.

    Science.gov (United States)

    Bullough, B

    1976-03-01

    Nursing has moved through two major phases in licensure. From 1900 to 1938 basic registration acts were passed and amended. In 1938 the goal became mandatory licensure for all those who nursed for hire. This move was linked with the stratification of the nursing role to include both practical and registered nurses. The third and current phase in licensure began in 1971 with the Idaho revision of the nurse practice act; 30 states have now revised their nurse practice acts to facilitate role expansion for registered nurses. Several approaches are being used in these laws including mandating new board regulations, expanding the definitions of nursing; increasing the power of physicians to delegate, and mandating the use of standardized protocols to guide the practice of nurses who are accepting new responsibilities.

  15. Expanding plasma jet in a vacuum vessel

    International Nuclear Information System (INIS)

    Chutov, Yu.I.; Kravchenko, A.Yu.; Yakovetskij, V.S.

    1998-01-01

    The paper deals with numerical calculations of parameters of a supersonic quasi-neutral argon plasma jet expanding into a cylindrical vacuum vessel and interacting with its inner surface. A modified method of large particles was used, the complex set of hydrodynamic equations being broken into simpler components, each of which describes a separate physical process. Spatial distributions of the main parameters of the argon plasma jet were simulated at various times after the jet entering the vacuum vessel, the parameters being the jet velocity field, the full plasma pressure, the electron temperature, the temperature of heavy particles, and the degree of ionization. The results show a significant effect of plasma jet interaction on the plasma parameters. The jet interaction with the vessel walls may result e.g. in excitation of shock waves and rotational plasma motions. (J.U.)

  16. Cosmic strings in an expanding spacetime

    International Nuclear Information System (INIS)

    Stein-Schabes, J.A.; Burd, A.B.

    1987-04-01

    We investigate the stability of a static, infinitely long and straight vacuum string solution under inhomogeneous axisymmetric time-dependent perturbations. We find it to be perturbatively stable. We further extend our work by finding a string solutions in an expanding Universe. The back reaction of the string on the gravitational field has been ignored. The background is assumed to be a Friedman-Robertson-Walker (FRW) cosmology. By numerically integrating the field equations in a radiation and matter dominated models, we discover oscillatory solutions. The possible damping of these oscillations is discussed. For late times the solution becomes identical to the static one studied in the first part of the paper. 19 refs., 8 figs

  17. Expanding the applicability of Heallth Technology Assessments

    DEFF Research Database (Denmark)

    Draborg, Eva; Hansen, Helle Ploug

    2012-01-01

    The objective of the presentation is to expand the foundations of input into policy decision making relying on health technology assessments (HTA). HTAs are primarily based on systematic reviews (SR) and thereby mostly on randomized controlled trials (RCT). RCTs can be distinguished on a continuum...... between explanatory and pragmatic trials according to their level of control over variables in the study besides the examined technology. In explanatory trials emphasis are placed on internal validity in order to test the efficacy of a technology under ideal conditions while pragmatic trials emphasizes...... external validity and the effectiveness of a technology in normal daily practice. SR and HTAs favors internal valid trials and thereby proofs of possible cause-effect relationship between a technology and outcomes but at the expense of the wider perspectives of a technology. HTA have a policy...

  18. The expanding universe of p53 targets.

    Science.gov (United States)

    Menendez, Daniel; Inga, Alberto; Resnick, Michael A

    2009-10-01

    The p53 tumour suppressor is modified through mutation or changes in expression in most cancers, leading to the altered regulation of hundreds of genes that are directly influenced by this sequence-specific transcription factor. Central to the p53 master regulatory network are the target response element (RE) sequences. The extent of p53 transactivation and transcriptional repression is influenced by many factors, including p53 levels, cofactors and the specific RE sequences, all of which contribute to the role that p53 has in the aetiology of cancer. This Review describes the identification and functionality of REs and highlights the inclusion of non-canonical REs that expand the universe of genes and regulation mechanisms in the p53 tumour suppressor network.

  19. Painful Na-channelopathies: an expanding universe.

    Science.gov (United States)

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Multifragment disintegrations of expanding nuclear systems

    International Nuclear Information System (INIS)

    Gelbke, K.

    1993-01-01

    Two phase transitions are expected to exist in bulk nuclear matter: a liquid-gas phase transition and a deconfinement transition to a quark-gluon plasma. In studies of nucleus-nucleus collisions, conditions similar to those pertaining to phase transitions in infinite systems can be created, but the fundamental problem yet to be solved is the identification of remnant signatures uniquely related to either of these phase transitions. Nuclear systems at densities and temperatures corresponding to the liquid-gas coexistence region can be produced in intermediate energy nucleus-nucleus collisions; they are expected to decay into many intermediate mass fragments (IMF's: Z=3-20). Recent investigations with low-threshold electronic 4π detector arrays have firmly established the occurrence of multifragment disintegrations of hot nuclear systems and allowed to challenge various theoretical approaches. In this talk, an overview of pertinent experimental results on multifragmentation will be presented and discussed. it will be shown that current microscopic transport theories designed to treat the growth of density fluctuations predict fragment multiplicities much smaller than observed experimentally. Measurements of the time scales of fragment formation are consistent with statistical model calculations for expanding hot nuclear system which indicate that fragments may form during a rather narrow time interval after the system has cooled and expanded to a density below that of normal nuclear matter. The expansion rate (and hence the fragment multiplicity) is sensitive to the equation of state (EOS). However, a number of recent results provide increasing evidence that current theoretical treatments need to be refined to allow an experimental determination of the EOS

  1. Interactive Exploration for Continuously Expanding Neuron Databases.

    Science.gov (United States)

    Li, Zhongyu; Metaxas, Dimitris N; Lu, Aidong; Zhang, Shaoting

    2017-02-15

    This paper proposes a novel framework to help biologists explore and analyze neurons based on retrieval of data from neuron morphological databases. In recent years, the continuously expanding neuron databases provide a rich source of information to associate neuronal morphologies with their functional properties. We design a coarse-to-fine framework for efficient and effective data retrieval from large-scale neuron databases. In the coarse-level, for efficiency in large-scale, we employ a binary coding method to compress morphological features into binary codes of tens of bits. Short binary codes allow for real-time similarity searching in Hamming space. Because the neuron databases are continuously expanding, it is inefficient to re-train the binary coding model from scratch when adding new neurons. To solve this problem, we extend binary coding with online updating schemes, which only considers the newly added neurons and update the model on-the-fly, without accessing the whole neuron databases. In the fine-grained level, we introduce domain experts/users in the framework, which can give relevance feedback for the binary coding based retrieval results. This interactive strategy can improve the retrieval performance through re-ranking the above coarse results, where we design a new similarity measure and take the feedback into account. Our framework is validated on more than 17,000 neuron cells, showing promising retrieval accuracy and efficiency. Moreover, we demonstrate its use case in assisting biologists to identify and explore unknown neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Roots Air Management System with Integrated Expander

    Energy Technology Data Exchange (ETDEWEB)

    Stretch, Dale [Eaton Corporation, Menomonee Falls, WI (United States); Wright, Brad [Eaton Corporation, Menomonee Falls, WI (United States); Fortini, Matt [Eaton Corporation, Menomonee Falls, WI (United States); Fink, Neal [Ballard Power Systems, Burnaby, BC (Canada); Ramadan, Bassem [Kettering Univ., Flint, MI (United States); Eybergen, William [Eaton Corporation, Menomonee Falls, WI (United States)

    2016-07-06

    PEM fuel cells remain an emerging technology in the vehicle market with several cost and reliability challenges that must be overcome in order to increase market penetration and acceptance. The DOE has identified the lack of a cost effective, reliable, and efficient air supply system that meets the operational requirements of a pressurized PEM 80kW fuel cell as one of the major technological barriers that must be overcome. This project leveraged Roots positive displacement development advancements and demonstrated an efficient and low cost fuel cell air management system. Eaton built upon its P-Series Roots positive displacement design and shifted the peak efficiency making it ideal for use on an 80kW PEM stack. Advantages to this solution include: • Lower speed of the Roots device eliminates complex air bearings present on other systems. • Broad efficiency map of Roots based systems provides an overall higher drive cycle fuel economy. • Core Roots technology has been developed and validated for other transportation applications. Eaton modified their novel R340 Twin Vortices Series (TVS) Roots-type supercharger for this application. The TVS delivers more power and better fuel economy in a smaller package as compared to other supercharger technologies. By properly matching the helix angle with the rotor’s physical aspect ratio, the supercharger’s peak efficiency can be moved to the operating range where it is most beneficial for the application. The compressor was designed to meet the 90 g/s flow at a pressure ratio of 2.5, similar in design to the P-Series 340. A net shape plastic expander housing with integrated motor and compressor was developed to significantly reduce the cost of the system. This integrated design reduced part count by incorporating an overhung expander and motor rotors into the design such that only four bearings and two shafts were utilized.

  3. BOOK REVIEW: The Artful Universe Expanded

    Science.gov (United States)

    Bassett, B. A.

    2005-07-01

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music—a new type of `cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson,\\endcolumn hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature’s code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one’s mind a vision that unifies science, art and culture and glimpse a universal tapestry of great

  4. Gravitomagnetic Instabilities in Anisotropically Expanding Fluids

    Science.gov (United States)

    Kleidis, Kostas; Kuiroukidis, Apostolos; Papadopoulos, Demetrios B.; Vlahos, Loukas

    Gravitational instabilities in a magnetized Friedman-Robertson-Walker (FRW) universe, in which the magnetic field was assumed to be too weak to destroy the isotropy of the model, are known and have been studied in the past. Accordingly, it became evident that the external magnetic field disfavors the perturbations' growth, suppressing the corresponding rate by an amount proportional to its strength. However, the spatial isotropy of the FRW universe is not compatible with the presence of large-scale magnetic fields. Therefore, in this paper we use the general-relativistic version of the (linearized) perturbed magnetohydrodynamic equations with and without resistivity, to discuss a generalized Jeans criterion and the potential formation of density condensations within a class of homogeneous and anisotropically expanding, self-gravitating, magnetized fluids in curved space-time. We find that, for a wide variety of anisotropic cosmological models, gravitomagnetic instabilities can lead to subhorizontal, magnetized condensations. In the nonresistive case, the power spectrum of the unstable cosmological perturbations suggests that most of the power is concentrated on large scales (small k), very close to the horizon. On the other hand, in a resistive medium, the critical wave-numbers so obtained, exhibit a delicate dependence on resistivity, resulting in the reduction of the corresponding Jeans lengths to smaller scales (well bellow the horizon) than the nonresistive ones, while increasing the range of cosmological models which admit such an instability.

  5. Expanding the usefulness of unit supply cost

    International Nuclear Information System (INIS)

    McKenzie, M.B.; Petr, K.

    1992-01-01

    Unit supply cost is a widely used tool in the energy business for providing a one number-unit cost description. For example, controllable costs such as finding costs, development costs and operating costs have traditionally been described in an average cost per unit of reserves format for the oil and gas industry, however using this approach on more specific applications is not always informative. Projects with widely varying controllable parameters can still yield the same unit cost, making comparisons difficult. The application of unit supply cost can be readily expanded by adding a new unit cost component termed cost of capital. This element introduces the impacts of timing and return on investment into the supply cost determination through discounting annual costs. The cost of capital component adds the ability to represent a project's unique characteristics, particularly reserves' depletion rate and the timing or phasing of development. Introducing the cost of capital element into the supply cost analysis provides additional information and improves the likelihood of drawing correct conclusions when comparing and ranking projects. 4 figs., 6 tabs

  6. Potential Expanded Indications for Neprilysin Inhibitors

    Science.gov (United States)

    Riddell, Elizabeth; Vader, Justin M.

    2017-01-01

    Purpose of review The goal of this article is to review potential expanded indications for neprilysin inhibitors. This article reviews the rationale and design for ongoing and future trials of sacubitril/valsartan in cardiovascular and non-cardiovascular disease. Recent findings Randomized trial data are lacking for use of sacubitril/valsartan in acute heart failure and advanced heart failure. Mechanistic data from animal studies suggest a role for neprilysin inhibition in the treatment of post-myocardial infarction systolic dysfunction and heart failure with preserved ejection fraction. Beyond the cardiovascular system, renal and neurological function may be impacted by neprilysin inhibition. Forthcoming randomized trials will address the clinical impact of sacubitril/valsartan on these conditions. Summary Neprolysin inhibition with sacubitril/valsartan offers a new therapeutic strategy with a broad range of potential therapeutic actions. In PARADIGM-HF, the combination of neprolysin and RAAS inhibition was proven to be superior to enalapril for patients with stable NYHA class II–III heart failure and reduced left ventricular ejection fraction. Preliminary data suggests it may also have a role in other cardiovascular and non-cardiovascular disease. Several ongoing and planned studies will determine the extent of its benefit for these other indications. PMID:28281174

  7. Homogeneous cosmology with aggressively expanding civilizations

    International Nuclear Information System (INIS)

    Jay Olson, S

    2015-01-01

    In the context of a homogeneous Universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarity to describe the dynamics of life saturating the Universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies. Through a series of numerical solutions spanning several orders of magnitude in the input assumption parameters, the resulting cosmological model is used to address basic questions related to the intergalactic spreading of life, dealing with issues such as timescales, observability, competition between strategies, and first-mover advantage. Finally, we examine physical effects on the Universe itself, such as reheating and the backreaction on the evolution of the scale factor, if such life is able to control and convert a significant fraction of the available pressureless matter into radiation. We conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the Universe. (paper)

  8. Expanding the genetic heterogeneity of intellectual disability.

    Science.gov (United States)

    Anazi, Shams; Maddirevula, Sateesh; Salpietro, Vincenzo; Asi, Yasmine T; Alsahli, Saud; Alhashem, Amal; Shamseldin, Hanan E; AlZahrani, Fatema; Patel, Nisha; Ibrahim, Niema; Abdulwahab, Firdous M; Hashem, Mais; Alhashmi, Nadia; Al Murshedi, Fathiya; Al Kindy, Adila; Alshaer, Ahmad; Rumayyan, Ahmed; Al Tala, Saeed; Kurdi, Wesam; Alsaman, Abdulaziz; Alasmari, Ali; Banu, Selina; Sultan, Tipu; Saleh, Mohammed M; Alkuraya, Hisham; Salih, Mustafa A; Aldhalaan, Hesham; Ben-Omran, Tawfeg; Al Musafri, Fatima; Ali, Rehab; Suleiman, Jehan; Tabarki, Brahim; El-Hattab, Ayman W; Bupp, Caleb; Alfadhel, Majid; Al Tassan, Nada; Monies, Dorota; Arold, Stefan T; Abouelhoda, Mohamed; Lashley, Tammaryn; Houlden, Henry; Faqeih, Eissa; Alkuraya, Fowzan S

    2017-11-01

    Intellectual disability (ID) is a common morbid condition with a wide range of etiologies. The list of monogenic forms of ID has increased rapidly in recent years thanks to the implementation of genomic sequencing techniques. In this study, we describe the phenotypic and genetic findings of 68 families (105 patients) all with novel ID-related variants. In addition to established ID genes, including ones for which we describe unusual mutational mechanism, some of these variants represent the first confirmatory disease-gene links following previous reports (TRAK1, GTF3C3, SPTBN4 and NKX6-2), some of which were based on single families. Furthermore, we describe novel variants in 14 genes that we propose as novel candidates (ANKHD1, ASTN2, ATP13A1, FMO4, MADD, MFSD11, NCKAP1, NFASC, PCDHGA10, PPP1R21, SLC12A2, SLK, STK32C and ZFAT). We highlight MADD and PCDHGA10 as particularly compelling candidates in which we identified biallelic likely deleterious variants in two independent ID families each. We also highlight NCKAP1 as another compelling candidate in a large family with autosomal dominant mild intellectual disability that fully segregates with a heterozygous truncating variant. The candidacy of NCKAP1 is further supported by its biological function, and our demonstration of relevant expression in human brain. Our study expands the locus and allelic heterogeneity of ID and demonstrates the power of positional mapping to reveal unusual mutational mechanisms.

  9. Withdrawal: Expanding a Key Addiction Construct.

    Science.gov (United States)

    Piper, Megan E

    2015-12-01

    Withdrawal is an essential component of classical addiction theory; it is a vital manifestation of dependence and motivates relapse. However, the traditional conceptualization of withdrawal as a cohesive collection of symptoms that emerge during drug deprivation and decline with either the passage of time or reinstatement of drug use, may be inadequate to explain scientific findings or fit with modern theories of addiction. This article expands the current understanding of tobacco withdrawal by examining: (1) withdrawal variability; (2) underlying causes of withdrawal variability, including biological and person factors, environmental influences, and the influence of highly routinized behavioral patterns; (3) new withdrawal symptoms that allow for enhanced characterization of the withdrawal experience; and (4) withdrawal-related cognitive processes. These topics provide guidance regarding the optimal assessment of withdrawal and illustrate the potential impact modern withdrawal conceptualization and assessment could have on identifying treatment targets. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Expanding the genetic heterogeneity of intellectual disability

    KAUST Repository

    Anazi, Shams

    2017-09-22

    Intellectual disability (ID) is a common morbid condition with a wide range of etiologies. The list of monogenic forms of ID has increased rapidly in recent years thanks to the implementation of genomic sequencing techniques. In this study, we describe the phenotypic and genetic findings of 68 families (105 patients) all with novel ID-related variants. In addition to established ID genes, including ones for which we describe unusual mutational mechanism, some of these variants represent the first confirmatory disease-gene links following previous reports (TRAK1, GTF3C3, SPTBN4 and NKX6-2), some of which were based on single families. Furthermore, we describe novel variants in 14 genes that we propose as novel candidates (ANKHD1, ASTN2, ATP13A1, FMO4, MADD, MFSD11, NCKAP1, NFASC, PCDHGA10, PPP1R21, SLC12A2, SLK, STK32C and ZFAT). We highlight MADD and PCDHGA10 as particularly compelling candidates in which we identified biallelic likely deleterious variants in two independent ID families each. We also highlight NCKAP1 as another compelling candidate in a large family with autosomal dominant mild intellectual disability that fully segregates with a heterozygous truncating variant. The candidacy of NCKAP1 is further supported by its biological function, and our demonstration of relevant expression in human brain. Our study expands the locus and allelic heterogeneity of ID and demonstrates the power of positional mapping to reveal unusual mutational mechanisms.

  11. Expanding the genetic heterogeneity of intellectual disability

    KAUST Repository

    Anazi, Shams; Maddirevula, Sateesh; Salpietro, Vincenzo; Asi, Yasmine T.; Alsahli, Saud; Alhashem, Amal; Shamseldin, Hanan E.; AlZahrani, Fatema; Patel, Nisha; Ibrahim, Niema; Abdulwahab, Firdous M.; Hashem, Mais; Alhashmi, Nadia; Al Murshedi, Fathiya; Al Kindy, Adila; Alshaer, Ahmad; Rumayyan, Ahmed; Al Tala, Saeed; Kurdi, Wesam; Alsaman, Abdulaziz; Alasmari, Ali; Banu, Selina; Sultan, Tipu; Saleh, Mohammed M.; Alkuraya, Hisham; Salih, Mustafa A.; Aldhalaan, Hesham; Ben-Omran, Tawfeg; Al Musafri, Fatima; Ali, Rehab; Suleiman, Jehan; Tabarki, Brahim; El-Hattab, Ayman W.; Bupp, Caleb; Alfadhel, Majid; Al Tassan, Nada; Monies, Dorota; Arold, Stefan T.; Abouelhoda, Mohamed; Lashley, Tammaryn; Houlden, Henry; Faqeih, Eissa; Alkuraya, Fowzan S.

    2017-01-01

    Intellectual disability (ID) is a common morbid condition with a wide range of etiologies. The list of monogenic forms of ID has increased rapidly in recent years thanks to the implementation of genomic sequencing techniques. In this study, we describe the phenotypic and genetic findings of 68 families (105 patients) all with novel ID-related variants. In addition to established ID genes, including ones for which we describe unusual mutational mechanism, some of these variants represent the first confirmatory disease-gene links following previous reports (TRAK1, GTF3C3, SPTBN4 and NKX6-2), some of which were based on single families. Furthermore, we describe novel variants in 14 genes that we propose as novel candidates (ANKHD1, ASTN2, ATP13A1, FMO4, MADD, MFSD11, NCKAP1, NFASC, PCDHGA10, PPP1R21, SLC12A2, SLK, STK32C and ZFAT). We highlight MADD and PCDHGA10 as particularly compelling candidates in which we identified biallelic likely deleterious variants in two independent ID families each. We also highlight NCKAP1 as another compelling candidate in a large family with autosomal dominant mild intellectual disability that fully segregates with a heterozygous truncating variant. The candidacy of NCKAP1 is further supported by its biological function, and our demonstration of relevant expression in human brain. Our study expands the locus and allelic heterogeneity of ID and demonstrates the power of positional mapping to reveal unusual mutational mechanisms.

  12. Expandable image compression system: A modular approach

    International Nuclear Information System (INIS)

    Ho, B.K.T.; Lo, S.C.; Huang, H.K.

    1986-01-01

    The full-frame bit-allocation algorithm for radiological image compression can achieve an acceptable compression ratio as high as 30:1. It involves two stages of operation: a two-dimensional discrete cosine transform and pixel quantization in the transformed space with pixel depth kept accountable by a bit-allocation table. The cosine transform hardware design took an expandable modular approach based on the VME bus system with a maximum data transfer rate of 48 Mbytes/sec and a microprocessor (Motorola 68000 family). The modules are cascadable and microprogrammable to perform 1,024-point butterfly operations. A total of 18 stages would be required for transforming a 1,000 x 1,000 image. Multiplicative constants and addressing sequences are to be software loaded into the parameter buffers of each stage prior to streaming data through the processor stages. The compression rate for 1K x 1K images is expected to be faster than one image per sec

  13. Expandable image compression system: A modular approach

    International Nuclear Information System (INIS)

    Ho, B.K.T.; Chan, K.K.; Ishimitsu, Y.; Lo, S.C.; Huang, H.K.

    1987-01-01

    The full-frame bit allocation algorithm for radiological image compression developed in the authors' laboratory can achieve compression ratios as high as 30:1. The software development and clinical evaluation of this algorithm has been completed. It involves two stages of operations: a two-dimensional discrete cosine transform and pixel quantization in the transform space with pixel depth kept accountable by a bit allocation table. Their design took an expandable modular approach based on the VME bus system which has a maximum data transfer rate of 48 Mbytes per second and a Motorola 68020 microprocessor as the master controller. The transform modules are based on advanced digital signal processor (DSP) chips microprogrammed to perform fast cosine transforms. Four DSP's built into a single-board transform module can process an 1K x 1K image in 1.7 seconds. Additional transform modules working in parallel can be added if even greater speeds are desired. The flexibility inherent in the microcode extends the capabilities of the system to incorporate images of variable sizes. Their design allows for a maximum image size of 2K x 2K

  14. Expanding the role of internal facility assessments

    Energy Technology Data Exchange (ETDEWEB)

    Kolpa, R.L.; Levenson, J.B. [Argonne National Lab., IL (United States); Weaver, M.A. [Headquarters Air Force Materiel Command, Wright-Patterson AFB, OH (United States)

    1996-05-01

    The US Air Force (USAF) Environmental Compliance Assessment and Management Program (ECAMP) is an effective and comprehensive system to evaluate environmental compliance at individual USAF installations. The ECAMP assessment is typically performed by a team of experts from the installation`s Major Command (MAJCOM) Headquarters, and is often augmented with technical contractor support. As directed by Air Force policy, an external ECAMP assessment is required at a minimum of every three years for each installation. In the intervening years, each installation is required to perform an internal ECAMP assessment, with its own personnel and resources. Even though team composition differs, the internal and external ECAMP assessments are likely to be very similar in scope, objectives, and deliverables. For over nine years, Argonne National Laboratory (ANL) has supported several Air Force MAJCOMs in performing their external ECAMP assessments. More recently, ANL has also had the opportunity to provide technical support and training at individual installations during their preparation and conduct of internal ECAMP assessments. From that experience, the authors have learned that the quality and value of the internal assessment is enhanced by making it a vehicle for training, planning, and interaction among organizations. Various strategies and techniques have been successfully employed to derive maximum benefit and insight from the internal assessment process. Experiences that involve expanding the scope and objectives of internal assessments to meet specific goals are presented. The expansion of scope and objectives include preassessment training, planning, and evaluator interactions as part of the overall internal assessment process.

  15. Expanding solvent SAGD in heavy oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Govind, P.A. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Das, S.; Wheeler, T.J. [Society of Petroleum Engineers, Richardson, TX (United States)]|[ConocoPhillips Co., Houston, TX (United States); Srinivasan, S. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Texas Univ., Austin, TX (United States)

    2008-10-15

    Steam assisted gravity drainage (SAGD) projects have proven effective for the recovery of oil and bitumen. Expanding solvent (ES) SAGD pilot projects have also demonstrated positive results of improved performance. This paper presented the results of a simulation study that investigated several important factors of the ES-SAGD process, including solvent types; concentration; operating pressure; and injection strategy. The objectives of the study were to examine the effectiveness of the ES-SAGD process in terms of production acceleration and energy requirements; to optimize solvent selection; to understand the effect of dilation in unconsolidated oil sands and the directional impact on reservoir parameters and oil production rate in ES-SAGD; and to understand the impact of operating conditions such as pressure, solvent concentration, circulation preheating period and the role of conduction heating and grid size in this process. The advantages of ES-SAGD over SAGD were also outlined. The paper presented results of sensitivity studies that were conducted on these four factors. Conclusions and recommendations for operating strategy were also offered. It was concluded that dilation is an important factor for SAGD performance at high operating pressure. 8 refs., 15 figs.

  16. The expanding universe of prion diseases.

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C. Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases-including human diseases variant Creutzfeldt-Jakob disease (vCJD and sporadic fatal insomnia (sFI, bovine amyloidotic spongiform encephalopathy (BASE, and Nor98 of sheep-have been identified in the last ten years, and chronic wasting disease (CWD of North American deer (Odocoileus Specis and Rocky Mountain elk (Cervus elaphus nelsoni is undergoing a dramatic spread across North America. While amplification (BSE and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded.

  17. The expanding universe of noncoding RNAs.

    Science.gov (United States)

    Hannon, G J; Rivas, F V; Murchison, E P; Steitz, J A

    2006-01-01

    The 71st Cold Spring Harbor Symposium on Quantitative Biology celebrated the numerous and expanding roles of regulatory RNAs in systems ranging from bacteria to mammals. It was clearly evident that noncoding RNAs are undergoing a renaissance, with reports of their involvement in nearly every cellular process. Previously known classes of longer noncoding RNAs were shown to function by every possible means-acting catalytically, sensing physiological states through adoption of complex secondary and tertiary structures, or using their primary sequences for recognition of target sites. The many recently discovered classes of small noncoding RNAs, generally less than 35 nucleotides in length, most often exert their effects by guiding regulatory complexes to targets via base-pairing. With the ability to analyze the RNA products of the genome in ever greater depth, it has become clear that the universe of noncoding RNAs may extend far beyond the boundaries we had previously imagined. Thus, as much as the Symposium highlighted exciting progress in the field, it also revealed how much farther we must go to understand fully the biological impact of noncoding RNAs.

  18. The expanding universe of prion diseases.

    Directory of Open Access Journals (Sweden)

    Joel C Watts

    2006-03-01

    Full Text Available Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C. Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases--including human diseases variant Creutzfeldt-Jakob disease (vCJD and sporadic fatal insomnia (sFI, bovine amyloidotic spongiform encephalopathy (BASE, and Nor98 of sheep--have been identified in the last ten years, and chronic wasting disease (CWD of North American deer (Odocoileus Specis and Rocky Mountain elk (Cervus elaphus nelsoni is undergoing a dramatic spread across North America. While amplification (BSE and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded.

  19. The expanding universe of prion diseases.

    Science.gov (United States)

    Watts, Joel C; Balachandran, Aru; Westaway, David

    2006-03-01

    Prions cause fatal and transmissible neurodegenerative disease. These etiological infectious agents are formed in greater part from a misfolded cell-surface protein called PrP(C). Several mammalian species are affected by the diseases, and in the case of "mad cow disease" (BSE) the agent has a tropism for humans, with negative consequences for agribusiness and public health. Unfortunately, the known universe of prion diseases is expanding. At least four novel prion diseases--including human diseases variant Creutzfeldt-Jakob disease (vCJD) and sporadic fatal insomnia (sFI), bovine amyloidotic spongiform encephalopathy (BASE), and Nor98 of sheep--have been identified in the last ten years, and chronic wasting disease (CWD) of North American deer (Odocoileus Specis) and Rocky Mountain elk (Cervus elaphus nelsoni) is undergoing a dramatic spread across North America. While amplification (BSE) and dissemination (CWD, commercial sourcing of cervids from the wild and movement of farmed elk) can be attributed to human activity, the origins of emergent prion diseases cannot always be laid at the door of humankind. Instead, the continued appearance of new outbreaks in the form of "sporadic" disease may be an inevitable outcome in a situation where the replicating pathogen is host-encoded.

  20. Expanding the Allowable TRUPACT-II Payload

    International Nuclear Information System (INIS)

    St Michel, W.; Lott, S.

    2002-01-01

    The partnership between the Carlsbad Field Office (CBFO) and the TRU and Mixed Waste Focus Area (TMFA) was rewarded when several long-term projects came to fruition. The Nuclear Regulatory Commission (NRC) removed some of the conservatism in the TRUPACT-II Safety Analysis Report for Packaging (SARP) with their approval of Revision 19. The SARP strictly limits the payload constituents to ensure that hydrogen gas and other flammable volatile organic compounds (VOCs) don't build up to flammable/explosive levels while the transuranic (TRU) waste is sealed in the container during shipment. The CBFO/TMFA development program was based on laboratory experiments with surrogate waste materials, real waste experiments, and theoretical modeling that were used to justify payload expansion. Future work to expand the shipping envelope of the TRUPACT-II focuses on increasing the throughput through the waste certification process and reducing the waste operations costs by removing the need for a repack aging and/or treatment capability or reducing the size of the needed repackaging/treatment capability

  1. Is expanding Medicare coverage cost-effective?

    Directory of Open Access Journals (Sweden)

    Muennig Peter

    2005-03-01

    Full Text Available Abstract Background Proposals to expand Medicare coverage tend to be expensive, but the value of services purchased is not known. This study evaluates the efficiency of the average private supplemental insurance plan for Medicare recipients. Methods Data from the National Health Interview Survey, the National Death Index, and the Medical Expenditure Panel Survey were analyzed to estimate the costs, changes in life expectancy, and health-related quality of life gains associated with providing private supplemental insurance coverage for Medicare beneficiaries. Model inputs included socio-demographic, health, and health behavior characteristics. Parameter estimates from regression models were used to predict quality-adjusted life years (QALYs and costs associated with private supplemental insurance relative to Medicare only. Markov decision analysis modeling was then employed to calculate incremental cost-effectiveness ratios. Results Medicare supplemental insurance is associated with increased health care utilization, but the additional costs associated with this utilization are offset by gains in quality-adjusted life expectancy. The incremental cost-effectiveness of private supplemental insurance is approximately $24,000 per QALY gained relative to Medicare alone. Conclusion Supplemental insurance for Medicare beneficiaries is a good value, with an incremental cost-effectiveness ratio comparable to medical interventions commonly deemed worthwhile.

  2. Massive Fermi gas in the expanding universe

    Energy Technology Data Exchange (ETDEWEB)

    Trautner, Andreas, E-mail: atrautner@uni-bonn.de [Bethe Center for Theoretical Physics and Physikalisches Institut der Universität Bonn, Nussallee 12, 53115 Bonn (Germany)

    2017-03-01

    The behavior of a decoupled ideal Fermi gas in a homogeneously expanding three-dimensional volume is investigated, starting from an equilibrium spectrum. In case the gas is massless and/or completely degenerate, the spectrum of the gas can be described by an effective temperature and/or an effective chemical potential, both of which scale down with the volume expansion. In contrast, the spectrum of a decoupled massive and non-degenerate gas can only be described by an effective temperature if there are strong enough self-interactions such as to maintain an equilibrium distribution. Assuming perpetual equilibration, we study a decoupled gas which is relativistic at decoupling and then is red-shifted until it becomes non-relativistic. We find expressions for the effective temperature and effective chemical potential which allow us to calculate the final spectrum for arbitrary initial conditions. This calculation is enabled by a new expansion of the Fermi-Dirac integral, which is for our purpose superior to the well-known Sommerfeld expansion. We also compute the behavior of the phase space density under expansion and compare it to the case of real temperature and real chemical potential. Using our results for the degenerate case, we also obtain the mean relic velocity of the recently proposed non-thermal cosmic neutrino background.

  3. Factors leading to tracheobronchial self-expandable metallic stent fracture.

    Science.gov (United States)

    Chung, Fu-Tsai; Lin, Shu-Min; Chen, Hao-Cheng; Chou, Chun-Liang; Yu, Chih-Teng; Liu, Chien-Ying; Wang, Chun-Hua; Lin, Horng-Chyuan; Huang, Chien-Da; Kuo, Han-Pin

    2008-11-01

    This retrospective study was to determine factors that contribute to self-expandable metallic stent fracture in patients with tracheobronchial disease. From 2001 to 2006, 139 patients (age, 62.1 +/- 15.4 years; range, 23-87 years) with benign (n = 62) and malignant (n = 77) tracheobronchial disease received 192 Ultraflex (Boston Scientific, Natick, Mass) self-expandable metallic stents (98 in patients with benign disease and 94 in patients with malignant disease). Seventeen fractured self-expandable metallic stents were found; the incidence was 12.2% (17/139 patients) among patients with tracheobronchial disease. Tortuous airway (odds ratio, 4.06; 95% confidence interval, 1.04-18.34; P = .04) independently predicted self-expandable metallic stent fracture. Most self-expandable metallic stent fractures (64.7%, 11/17) were detected 500 to 1000 days after self-expandable metallic stent implantation. Clinical presentations for patients with fractured self-expandable metallic stents included dyspnea exacerbation (70.6%, 12/17) and cough (23.5%, 4/17). Self-expandable metallic stent fracture is not uncommon in patients with tracheobronchial disease. Tortuous airway is an independent predictor for it. Although management of the fractured self-expandable metallic stent in our study was feasible and safe, self-expandable metallic stents should be restricted to a more select population.

  4. Expanding Awareness of Docosahexaenoic Acid during Pregnancy

    Directory of Open Access Journals (Sweden)

    Barbara J. Meyer

    2013-04-01

    Full Text Available Pregnant women do not currently meet the consensus recommendation for docosahexaenoic acid (DHA (≥200 mg/day. Pregnant women in Australia are not receiving information on the importance of DHA during pregnancy. DHA pregnancy education materials were developed using current scientific literature, and tested for readability and design aesthetics. The study aimed to evaluate their usefulness, the desire for pregnant women to receive these materials and whether a larger separate study (using a control group is warranted to evaluate the influence the materials may have on increasing DHA consumption in pregnant women in Australia. Pregnant women (N = 118 were recruited at antenatal clinics at two NSW hospitals. Participants completed a 16-item questionnaire and DHA educational materials (pamphlet and shopping card were provided. Participants were contacted via phone two weeks later and completed the second questionnaire (25-item, N = 74. Statistics were conducted in SPSS and qualitative data were analysed to identify common themes. Ninety three percent of women found the materials useful, with the main reason being it expanded their knowledge of DHA food sources. Only 34% of women had received prior information on DHA, yet 68% said they would like to receive information. Due to the small sample size and lack of a control group, this small study cannot provide a cause and effect relationship between the materials and nutrition related behaviours or knowledge, however the results indicate a potential positive influence towards increased fish consumption and awareness of DHA containing foods. This suggests a larger study, with a control group is warranted to identify the impact such materials could have on Australian pregnant women.

  5. Ecological connectivity networks in rapidly expanding cities.

    Science.gov (United States)

    Nor, Amal Najihah M; Corstanje, Ron; Harris, Jim A; Grafius, Darren R; Siriwardena, Gavin M

    2017-06-01

    Urban expansion increases fragmentation of the landscape. In effect, fragmentation decreases connectivity, causes green space loss and impacts upon the ecology and function of green space. Restoration of the functionality of green space often requires restoring the ecological connectivity of this green space within the city matrix. However, identifying ecological corridors that integrate different structural and functional connectivity of green space remains vague. Assessing connectivity for developing an ecological network by using efficient models is essential to improve these networks under rapid urban expansion. This paper presents a novel methodological approach to assess and model connectivity for the Eurasian tree sparrow ( Passer montanus ) and Yellow-vented bulbul ( Pycnonotus goiavier ) in three cities (Kuala Lumpur, Malaysia; Jakarta, Indonesia and Metro Manila, Philippines). The approach identifies potential priority corridors for ecological connectivity networks. The study combined circuit models, connectivity analysis and least-cost models to identify potential corridors by integrating structure and function of green space patches to provide reliable ecological connectivity network models in the cities. Relevant parameters such as landscape resistance and green space structure (vegetation density, patch size and patch distance) were derived from an expert and literature-based approach based on the preference of bird behaviour. The integrated models allowed the assessment of connectivity for both species using different measures of green space structure revealing the potential corridors and least-cost pathways for both bird species at the patch sites. The implementation of improvements to the identified corridors could increase the connectivity of green space. This study provides examples of how combining models can contribute to the improvement of ecological networks in rapidly expanding cities and demonstrates the usefulness of such models for

  6. Expanding the boundaries of local similarity analysis.

    Science.gov (United States)

    Durno, W Evan; Hanson, Niels W; Konwar, Kishori M; Hallam, Steven J

    2013-01-01

    Pairwise comparison of time series data for both local and time-lagged relationships is a computationally challenging problem relevant to many fields of inquiry. The Local Similarity Analysis (LSA) statistic identifies the existence of local and lagged relationships, but determining significance through a p-value has been algorithmically cumbersome due to an intensive permutation test, shuffling rows and columns and repeatedly calculating the statistic. Furthermore, this p-value is calculated with the assumption of normality -- a statistical luxury dissociated from most real world datasets. To improve the performance of LSA on big datasets, an asymptotic upper bound on the p-value calculation was derived without the assumption of normality. This change in the bound calculation markedly improved computational speed from O(pm²n) to O(m²n), where p is the number of permutations in a permutation test, m is the number of time series, and n is the length of each time series. The bounding process is implemented as a computationally efficient software package, FASTLSA, written in C and optimized for threading on multi-core computers, improving its practical computation time. We computationally compare our approach to previous implementations of LSA, demonstrate broad applicability by analyzing time series data from public health, microbial ecology, and social media, and visualize resulting networks using the Cytoscape software. The FASTLSA software package expands the boundaries of LSA allowing analysis on datasets with millions of co-varying time series. Mapping metadata onto force-directed graphs derived from FASTLSA allows investigators to view correlated cliques and explore previously unrecognized network relationships. The software is freely available for download at: http://www.cmde.science.ubc.ca/hallam/fastLSA/.

  7. Research on boiling liquid expanding vapour explosions

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, C.A.; Steward, F.R.; Venart, J.E.S.

    A boiling liquid expanding vapor explosion (BLEVE) is due to rapid boiling and expansion, with no ignition or chemical reaction involved. Research is being conducted to examine such questions as under what conditions tanks and their contents undergo BLEVE, what are the characteristics of tanks affected by BLEVE, and what alterations in tank design can be made to minimize the likelihood of BLEVEs. Experiments have been done with both propane and freon, using commercially available one-liter propane cylinders. Outdoor tests were conducted and designed to have the tank fail at a particular set of internal conditions. High speed photography was used to record the explosion, and computerized monitoring equipment to record temperature and pressure data. Tests were run to attempt to determine the relationship between temperature and BLEVEs, and to test the possibility that the occurrence of a BLEVE depends on the amount of vapor that could be produced when the tank was ruptured. Discussion is made of the role of pressure waves and rarefaction waves in the explosion. It is concluded that the superheat temperature limit, theorized as the minimum temperature below which no BLEVE can occur, cannot be used to predict BLEVEs. It has been shown that BLEVEs can occur below this temperature. There appears to be a relationship between liquid temperature, liquid volume, and the energy required to drive the BLEVE. Fireballs may occur after a BLEVE of flammable material, but are not part of the tank destruction. Rupture location (vapor vs liquid space) appears to have no effect on whether a container will undergo a BLEVE. 7 refs., 7 figs., 1 tab.

  8. Gonadotropin releasing hormone agonists: Expanding vistas

    Directory of Open Access Journals (Sweden)

    Navneet Magon

    2011-01-01

    Full Text Available Gonadotropin-releasing hormone (GnRH agonists are derived from native GnRH by amino acid substitution which yields the agonist resistant to degradation and increases its half-life. The hypogonadotropic hypogonadal state produced by GnRH agonists has been often dubbed as "pseudomenopause" or "medical oophorectomy," which are both misnomers. GnRH analogues (GnRH-a work by temporarily "switching off" the ovaries. Ovaries can be "switched off" for the therapy and therapeutic trial of many conditions which include but are not limited to subfertility, endometriosis, adenomyosis, uterine leiomyomas, precocious puberty, premenstrual dysphoric disorder, chronic pelvic pain, or the prevention of menstrual bleeding in special clinical situations. Rapidly expanding vistas of usage of GnRH agonists encompass use in sex reassignment of male to female transsexuals, management of final height in cases of congenital adrenal hyperplasia, and preserving ovarian function in women undergoing cytotoxic chemotherapy. Hypogonadic side effects caused by the use of GnRH agonists can be tackled with use of "add-back" therapy. Goserelin, leuprolide, and nafarelin are commonly used in clinical practice. GnRH-a have provided us a powerful therapeutic approach to the treatment of numerous conditions in reproductive medicine. Recent synthesis of GnRH antagonists with a better tolerability profile may open new avenues for both research and clinical applications. All stakeholders who are partners in women′s healthcare need to join hands to spread awareness so that these drugs can be used to realize their full potential.

  9. PROFAM expands Mexican family planning clinics.

    Science.gov (United States)

    1983-01-01

    Mexico's private, nonprofit social marketing company, known as PROFAM, intends to expand its family planning clinics to marginal urban areas. The clinics are part of PROFAM's push to diversify social marketing outlets for contraceptive products and other birth control methods. PROFAM expects to establish 3 new clinics, possibly including a pregnancy test laboratory, a small 1-doctor clinic, and a large clinic housing an operating room. 1 clinic will be located outside the Mexico City area, the program's traditional boundaries. The company currently runs 2 small clinics and a pregnancy testing laboratory in Ciudad Netzahualcoyti, a community of 3.5 million on Mexico City's outskirts. PROFAM recently obtaine d government approval to sell condoms in food stores, which should increase distribtuion and sales. Currently, the company sells over 1 million high quality, lubricated condoms each month, accounting for over half of the Mexican market. Distribution covers 85% of the country's drugstore. Program setbacks occurred in 1981, when the Mexican government cancelled PROFAM's sales permits for all contraceptive products except condoms. Cancelled products included an oral contraceptive and 3 vaginal spermicides. These 4 products had provided nearly 100,000 couple years of protection in 1979 and an estimated 120,000 CYP 1980. During 1979 and 1980, condoms provided about 27,000 and 60,000 CYP, respectively. PROFAM had relied heavily on the pill and spermicides because its early studies showed condoms had a negative image in Mexico, due largely to the product's association with extramarital affairs. To counter this, PROFAM launched a widespread, free product sampling program in 1979, along with a continuing educational and advertising drive. Subsequent consumer surveys revealed a marked increase in product acceptance, with PROFAM's condom becoming the most widely known brand available in Mexico.

  10. AstroCom NYC: Expanding the Partnership

    Science.gov (United States)

    Paglione, Timothy; Ford, Saavik; Agueros, Marcel A.; Mac Low, Mordecai-Mark; Robbins, Dennis

    2015-01-01

    AstroCom NYC is an undergraduate mentoring program designed to improve urban minority student access to opportunities in astrophysical research by greatly enhancing partnerships between research astronomers in New York City (City University of New York - an MSI, American Museum of Natural History, and Columbia). AstroCom NYC provides centralized, personalized mentoring as well as financial and academic support, to CUNY undergraduates throughout their studies, plus the resources and opportunities to further CUNY faculty research with students. The goal is that students' residency at AMNH helps them build a sense of belonging in the field, and readies and inspires them for graduate study. AstroCom NYC provides a rigorous Methods of Scientific Research course developed specifically to this purpose, a laptop, research and career mentors, outreach activities, scholarships and stipends, Metrocards, and regular assessment for maximum effectiveness. Stipends in part alleviate the burdens at home typical for CUNY students so they may concentrate on their academic success. AMNH serves as the central hub for our faculty and students, who are otherwise dispersed among all five boroughs of the City. For our second cohort, we dramatically improved the application and screening process, implemented a number of tools to evaluate their potential for grad school, and began growing a network of potential hosts for summer internships around NY State and the US. We review these implementations and outcomes, as well as plans for Year 3, when we expect many of our current students to compete for external summer REUs, and after greatly expanding the program reach through a NASA community college initiative.

  11. Ecological connectivity networks in rapidly expanding cities

    Directory of Open Access Journals (Sweden)

    Amal Najihah M. Nor

    2017-06-01

    Full Text Available Urban expansion increases fragmentation of the landscape. In effect, fragmentation decreases connectivity, causes green space loss and impacts upon the ecology and function of green space. Restoration of the functionality of green space often requires restoring the ecological connectivity of this green space within the city matrix. However, identifying ecological corridors that integrate different structural and functional connectivity of green space remains vague. Assessing connectivity for developing an ecological network by using efficient models is essential to improve these networks under rapid urban expansion. This paper presents a novel methodological approach to assess and model connectivity for the Eurasian tree sparrow (Passer montanus and Yellow-vented bulbul (Pycnonotus goiavier in three cities (Kuala Lumpur, Malaysia; Jakarta, Indonesia and Metro Manila, Philippines. The approach identifies potential priority corridors for ecological connectivity networks. The study combined circuit models, connectivity analysis and least-cost models to identify potential corridors by integrating structure and function of green space patches to provide reliable ecological connectivity network models in the cities. Relevant parameters such as landscape resistance and green space structure (vegetation density, patch size and patch distance were derived from an expert and literature-based approach based on the preference of bird behaviour. The integrated models allowed the assessment of connectivity for both species using different measures of green space structure revealing the potential corridors and least-cost pathways for both bird species at the patch sites. The implementation of improvements to the identified corridors could increase the connectivity of green space. This study provides examples of how combining models can contribute to the improvement of ecological networks in rapidly expanding cities and demonstrates the usefulness of such

  12. Origin and dynamics of expanding neutral hydrogen supershells

    International Nuclear Information System (INIS)

    Kolesnik, I.G.; Silich, S.A.

    1987-01-01

    The evolutionary model of expanding supershells regulated by induced star formation is proposed. It is suggested that giant expanding shells are formed n superclouds at late evolutionary stage of star complexes. To understand the dynamics of the most huge supershells it is necessary to take into account that expanding shells can trigger star formation in cold dense pre-exosting cloudlets. Efficiency of induced star formation must be less than one percent to fit observational properties of supershells

  13. Infrastructure Requirements for an Expanded Fuel Ethanol Industry

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, Robert E. [Downstream Alternatives, Inc., South Bend, IN (United States)

    2002-01-15

    This report provides technical information specifically related to ethanol transportation, distribution, and marketing issues. This report required analysis of the infrastructure requirements for an expanded ethanol industry.

  14. Expanded beam (macro-imaging) ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Fried, M., E-mail: fried@mfa.kfki.h [Res. Inst. for Technical Physics and Materials Science (MFA), H-1525 Budapest, POB 49 (Hungary); Juhasz, G.; Major, C.; Petrik, P.; Polgar, O. [Res. Inst. for Technical Physics and Materials Science (MFA), H-1525 Budapest, POB 49 (Hungary); Horvath, Z. [Res. Inst. for Solid State Physics and Optics (SZFKI), H-1525 Budapest, POB 49 (Hungary); Nutsch, A. [Fraunhofer Institut fuer Integrierte Systeme und Bauelementetechnologie IISB, Schottkystr. 10, 91058 Erlangen (Germany)

    2011-02-28

    Our aim was to make possible to use spectroscopic ellipsometry for mapping purposes during one measuring cycle (minimum one rotation period of polarizer or analyzer) on many sample points. Our new technique uses non-collimated (non-parallel, mostly diffuse) illumination with an angle of incidence sensitive pinhole camera detector system and it works as an unusual kind of imaging ellipsometry. Adding multicolour supplemets, it provides spectral (a few wavelengths on a 2D image or a full spectrum along a line) information from rapid measurements of many points on a large (several dm2) area. This technique can be expanded by upscaling the geometry (upscaling the dimensions of the instrument, and characteristic imaging parameters such as focal lengths, distances, etc.). The lateral resolution is limited by the minimum resolved-angle determined by the detector system, mainly by the diameter of the pinhole. (The diameter of the pinhole is a compromise between the light intensity and the lateral resolution.) Small-aperture (25 mm diameter) polarizers are incorporated into both the polarization state generator (PSG) and polarization state detection (PSD) components of the instrument. The detection is almost without background because the pinhole serves as a filter against the scattered light. One rapid measuring cycle (less than 10 s) is enough to determine the polarization state at all the points inside the illuminated area. The collected data can be processed very fast (seconds) providing nearly real-time thicknesses and/or refractive index maps over many points of the sample surface even in the case of multilayer samples. The speed of the measuring system makes it suitable for using even on production lines. The necessary (in each sample-point different) angle-of-incidence and the mirror-effect calibration are made via well-known and optimized structures such as silicon/silicon-dioxide samples. The precision is suitable for detecting sub-nanometer thickness and a

  15. Expanding policy options for educating teenagers.

    Science.gov (United States)

    Stern, David

    2009-01-01

    David Stern argues that some basic features of the American high school must be modified if it is to serve all students successfully. He notes, for example, that only three-quarters of U.S. high school students graduate four years after beginning ninth grade and that the National Assessment of Educational Progress found no improvement in reading or mathematics for seventeen-year-olds between 1971 and 2004. The nation's system for educating teenagers, says Stern, seems to be stuck, despite the constant efforts of teachers and repeated waves of reform. Citing two widely accepted public purposes of educating teenagers-preparation for civic participation and for economic self-sufficiency-Stern proposes four new strategies to achieve those goals. He draws on empirical evidence suggesting that these are promising directions for research and policy, but acknowledges that existing studies provide only limited guidance. First, he says, schools should continue the current trend toward integrating educational options to provide young people with skills and experiences that pave the way to both college and careers. Second, states and districts should tie education funding not simply to the number of students attending school, but also to what young people learn, whether they graduate, and whether they find jobs or enroll in postsecondary education. Such a move, he argues, would encourage teaching and learning formats that use students' time more effectively. Third, more adults in addition to classroom teachers should be involved in educating teenagers. Other adults acting as academic advisers, learning coaches, student advocates, internship supervisors, mentors, and college counselors could help guide the education of teenagers inside and outside of school and provide some relief for the chronic shortage of teachers. Fourth, schools should expand the options for educating teenagers outside of geographically fixed schools. Combining improved Internet-based curriculum with

  16. Vietnam seeks help expanding voluntary surgical contraception.

    Science.gov (United States)

    Piet-pelon, N J; Sukop, S

    1992-07-01

    Recent surveys by the Vietnamese Ministry of Health suggest that 60% of married women desire no more children. Yet only 2% of currently married women and less than 1/2 of 1% of their partners use sterilization. Underscoring the high unmet need for effective family planning, over 1 million abortions (legal in Vietnam for the past 20 years) are performed annually. This rate corresponds to 1 abortion for every live birth. The Ministry of Health has recently welcomed a variety of organizations, including AVSC, whose assistance can help expand the country's family planning programs. Sorely lacking in supplies, equipment, and trained personnel, Vietnam has merited priority status--2nd only to China and India--from the UNFPA, which has committed $36 million over the next 4 years. Other organizations currently working in Vietnam include the Population Council, the Population Crisis Committee, and the International Planned Parenthood Federation. Despite enormous casualties during the war years, and a decrease since the 1970s in average family size from 6 to 4 children, the population of Vietnam has continued to grow rapidly, far outpacing economic growth. Currently 67 million, the population is expected to reach 80 million by the year 2000. The average Vietnamese annual income is only $195, among the lowest in the world. Doi moi, the process of economic reform begun in 1986, coupled with new government incentives for families who have no more than 2 children, is changing the face of family planning in Vietnam. Newly opened pharmacies sell imported birth control pills and condoms (to those who can afford them), while government hospitals and health clinics provide mainly IUDs, in addition to limited supplies of pills and condoms. Throughout the country, some 8000 community-level health centers are staffed by nurse-midwives trained in family planning. Voluntary sterilization is available at the district, provincial, and national hospitals. All married women may obtain family

  17. Expanding Horizons Teachers and Scientists Collabortaing

    Science.gov (United States)

    Teres, A.

    2017-12-01

    As a participant in PolarTrec, I joined the crew of NASA's Operation IceBridge in Greenland for the month of April 2017. As an active member of the team I learned the ins and outs of field research, and I learned about the work done by Operation IceBridge. As a result of participating in this project, I grew as a teacher and a scientist. I took my experiences and shared them with my classroom through stories, pictures, videos, and my lesson plans. By seeing the Artic through my experiences the class became enraptured by the subject matter. I was no longer talking about a distant or abstract place instead I was talking about an experience. This enabled my students to take an active part in the discussion and to feel like the cryosphere was part of their life too. Not only did I learn about the science but I leaned about logistics of field research. I reached out to my community and local communications outlets before and after my trip to Greenland to familiarize whomever I could connect with about my experience. I contacted a local news station and they did an interview with me about my trip. I emailed a local newspaper about my trip and was interviewed before I left and after I returned. Due to the newscast, I was contacted by my college sorority and was interviewed for the sorority's national newsletter which is distributed throughout the United States. Each connection helped to spread the word. I'm continuing to spread the word by volunteering to present my experience to schools throughout Broward County in Florida. I've already connected with teachers and schools to set up my presentation in the calendar. Having these types of experiences is critical for teachers to continue their growth within the scientific field and education. Effective teachers are those not constrained by the walls of their classroom. Having the opportunity to work with scientists and do research in the field has expanded my horizons. The people I met I am still in contact with and I am

  18. Expanded beam (macro-imaging) ellipsometry

    International Nuclear Information System (INIS)

    Fried, M.; Juhasz, G.; Major, C.; Petrik, P.; Polgar, O.; Horvath, Z.; Nutsch, A.

    2011-01-01

    Our aim was to make possible to use spectroscopic ellipsometry for mapping purposes during one measuring cycle (minimum one rotation period of polarizer or analyzer) on many sample points. Our new technique uses non-collimated (non-parallel, mostly diffuse) illumination with an angle of incidence sensitive pinhole camera detector system and it works as an unusual kind of imaging ellipsometry. Adding multicolour supplemets, it provides spectral (a few wavelengths on a 2D image or a full spectrum along a line) information from rapid measurements of many points on a large (several dm2) area. This technique can be expanded by upscaling the geometry (upscaling the dimensions of the instrument, and characteristic imaging parameters such as focal lengths, distances, etc.). The lateral resolution is limited by the minimum resolved-angle determined by the detector system, mainly by the diameter of the pinhole. (The diameter of the pinhole is a compromise between the light intensity and the lateral resolution.) Small-aperture (25 mm diameter) polarizers are incorporated into both the polarization state generator (PSG) and polarization state detection (PSD) components of the instrument. The detection is almost without background because the pinhole serves as a filter against the scattered light. One rapid measuring cycle (less than 10 s) is enough to determine the polarization state at all the points inside the illuminated area. The collected data can be processed very fast (seconds) providing nearly real-time thicknesses and/or refractive index maps over many points of the sample surface even in the case of multilayer samples. The speed of the measuring system makes it suitable for using even on production lines. The necessary (in each sample-point different) angle-of-incidence and the mirror-effect calibration are made via well-known and optimized structures such as silicon/silicon-dioxide samples. The precision is suitable for detecting sub-nanometer thickness and a

  19. In Vitro Comparison of Self-Expanding Versus Balloon-Expandable Stents in a Human Ex Vivo Model

    International Nuclear Information System (INIS)

    Grenacher, Lars; Rohde, Stefan; Gaenger, Ellen; Deutsch, Jochen; Kauffmann, Guenter W.; Richter, Goetz M.

    2006-01-01

    The objective was to compare the radial strength and expansile precision of self-expanding stents and balloon-expandable stents in a human cadaver bifurcation model. Seven different self-expanding (LUMINEXX, JOSTENT SelfX, JOSTENT SelfX hrf, Sinus-Repo, Sinus SuperFlex, Easy Wallstent, SMART) and four different balloon-expandable stent models (Palmaz, Sinus Stent, SAXX Medium, JOSTENT peripheral), each type 10 stents (total n = 110 stents) were implanted into the common iliac arteries of human cadaver corpses. The maximum stent diameter was 10 mm for all models. After stent implantation, the specimens were filled with silicone caoutchouc. After 24 h, the vascular walls including the stents were removed from the hardened casts. Diameters were taken and the weight of the cast cylinders was measured in air and in purified water to calculate the volume of the bodies (according to Archimedes Law) as a relative but precise degree for the radial strength of the implanted stents. The cylindrical casts of the self-expanding stents showed lower mean diameters (8.2 ± 1.0 mm) and mean volumes (0.60 ± 0.14 ml/cm) than in the balloon-expandable stent group (10.1 ± 0.3 mm and 0.71 ± 0.04 ml/cm, respectively; p < 0.01). The nominal maximum diameter of 10 mm was not achieved in any of the self-expanding stents, but this was achieved in more than 70% (29/40) of the balloon-expandable stent specimens (p < 0.05). The variation between achieved volumes was significantly larger in self-expanding (range: 0.23-0.78 ml/cm) than in balloon-expandable stents (range: 0.66-0.81 ml/cm; p < 0.05). Self-expanding stents presented considerably lower radial expansion force and lower degree of precision than balloon-expandable stents

  20. New York: Expanding Time, Increasing Opportunities for Achievement

    Science.gov (United States)

    Miller, Tiffany D.

    2014-01-01

    New York is poised to take an important step to improve student achievement by expanding learning time for students attending high-poverty, low-performing schools. Recent district- and state-level investments in expanded learning time--a promising strategy to close achievement and opportunity gaps--will give students more time to learn core…

  1. Conference Offers Girls Opportunity to Expand Career Horizons

    Science.gov (United States)

    Offers Girls Opportunity to Expand Career Horizons For more information contact: e:mail: Public Affairs Golden, Colo., Feb. 11, 1997 -- Expanding Your Horizons, a conference for girls grades 6 - 9 and Employed Women, Girls Incorporated of Metro Denver, King Soopers, McDonalds, the TCI Adult Program and the

  2. An Isothermal Steam Expander for an Industrial Steam Supplying System

    Directory of Open Access Journals (Sweden)

    Chen-Kuang Lin

    2015-01-01

    Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

  3. Principles of the fifth order tuning of beam expanders

    International Nuclear Information System (INIS)

    Meot, F.; Aniel, T.

    1995-01-01

    An analytical treatment of the third and fifth order optics of beam expanders is described, which allows precise tuning of the optical elements of the beam line, and efficient optimization of the beam uniformizing at the extended target. An application to a two-dimensional expander is given as an illustration. (authors)

  4. Influence Of Collapsing Matter On The Enveloping Expanding Universe

    OpenAIRE

    Choudhury, A. Latif

    2005-01-01

    Using a collapsing matter model at the center of an expanding universe as described by Weinberg we assume a special type of generated pressure. This pressure transmits into the surrounding expanding universe. Under certain restriction the ensuing hubble parameter is positive. The deacceleration parameter fluctuates with time, indicating that the universe accelerates for certain time and decelerates for other time intervals.

  5. Backyard Telescopes Watch an Expanding Binary

    Science.gov (United States)

    Kohler, Susanna

    2018-01-01

    What can you do with a team of people armed with backyard telescopes and a decade of patience? Test how binary star systems evolve under Einsteins general theory of relativity!Unusual VariablesCataclysmic variables irregularly brightening binary stars consisting of an accreting white dwarf and a donor star are a favorite target among amateur astronomers: theyre detectable even with small telescopes, and theres a lot we can learn about stellar astrophysics by observing them, if were patient.Diagram of a cataclysmic variable. In an AM CVn, the donor is most likely a white dwarf as well, or a low-mass helium star. [Philip D. Hall]Among the large family of cataclysmic variables is one unusual type: the extremely short-period AM Canum Venaticorum (AM CVn) stars. These rare variables (only 40 are known) are unique in having spectra dominated by helium, suggesting that they contain little or no hydrogen. Because of this, scientists have speculated that the donor stars in these systems are either white dwarfs themselves or very low-mass helium stars.Why study AM CVn stars? Because their unusual configuration allows us to predict the behavior of their orbital evolution. According to the general theory of relativity, the two components of an AM CVn will spiral closer and closer as the system loses angular momentum to gravitational-wave emission. Eventually they will get so close that the low-mass companion star overflows its Roche lobe, beginning mass transfer to the white dwarf. At this point, the orbital evolution will reverse and the binary orbit will expand, increasing its period.CBA member Enrique de Miguel, lead author on the study, with his backyard telescope in Huelva, Spain. [Enrique de Miguel]Backyard Astronomy Hard at WorkMeasuring the evolution of an AM CVns orbital period is the best way to confirm this model, but this is no simple task! To observe this evolution, we first need a system with a period that can be very precisely measured best achieved with an

  6. Crystallization degree change of expanded graphite by milling and annealing

    International Nuclear Information System (INIS)

    Tang Qunwei; Wu Jihuai; Sun Hui; Fang Shijun

    2009-01-01

    Expanded graphite was ball milled with a planetary mill in air atmosphere, and subsequently thermal annealed. The samples were characterized by using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). It was found that in the milling initial stage (less than 12 h), the crystallization degree of the expanded graphite declined gradually, but after milling more than 16 h, a recrystallization of the expanded graphite toke place, and ordered nanoscale expanded graphite was formed gradually. In the annealing initial stage, the non-crystallization of the graphite occurred, but, beyond an annealing time, recrystallizations of the graphite arise. Higher annealing temperature supported the recrystallization. The milled and annealed expanded graphite still preserved the crystalline structure as raw material and hold high thermal stability.

  7. Distant Supernovae Indicate Ever-Expanding Universe

    Science.gov (United States)

    1998-12-01

    ESO Astronomers Contribute towards Resolution of Cosmic Puzzle Since the discovery of the expansion of the Universe by American astronomer Edwin Hubble in the 1920's, by measurement of galaxy velocities, astronomers have tried to learn how this expansion changes with time. Until now, most scientists have been considering two possibilities: the expansion rate is slowing down and will ultimately either come to a halt - whereafter the Universe would start to contract, or it will continue to expand forever. However, new studies by two independent research teams, based on observations of exploding stars ( supernovae ) by ESO astronomers [1] with astronomical telescopes at the La Silla Observatory as well as those of their colleagues at other institutions, appear to show that the expansion of the Universe is accelerating . The results take the discovery of the cosmological expansion one step further and challenge recent models of the Universe. If the new measurements are indeed correct, they show that the elusive "cosmological constant" , as proposed by Albert Einstein , contributes significantly to the evolution of the Universe. The existence of a non-zero cosmological constant implies that a repulsive force, counter-acting gravity, currently dominates the universal expansion , and consequently leads to an ever-expanding Universe. This new research is being named as the "Breakthrough of the Year" by the renowned US science journal Science in the December 18, 1998, issue. A Press Release is published by the journal on this occasion. "Fundamental Parameters" of the Universe Three fundamental parameters govern all cosmological models based on the theory of General Relativity. They are 1. the current expansion rate as described by Hubble's constant , i.e. the proportionality factor between expansion velocity and distance 2. the average matter density in the Universe, and 3. the amount of "other energy" present in space. From the measured values of these fundamental

  8. Rupture of an expander prosthesis mimics axillary cancer recurrence.

    LENUS (Irish Health Repository)

    Ismael, T

    2005-10-01

    Regional silicone gel migration from a ruptured breast implant has been reported at different locations including the upper extremity, chest wall muscles, axilla and back. We report a patient who presented with an axillary mass that mimicked a regional recurrence 5 years after breast cancer reconstruction with a latissimus dorsi musculocutaneous flap and silicon gel expander-prosthesis. Surgical exploration revealed that the mass contained silicone gel around the port of the breast expander that had ruptured. The mass was confluent with an intracapsular silicone leak through a tract along the tube of the expander port.

  9. Prebiotic chemistry: Ribozyme takes its vitamins

    Science.gov (United States)

    Burrows, Cynthia J.

    2013-11-01

    Selection of an RNA catalyst that can use the vitamin thiamin to catalyse a key metabolic decarboxylation reaction has broad implications for understanding the role of RNA in the early stages of chemical evolution.

  10. Expanding Agricultural and Rural Extension Roles for Sustainable ...

    African Journals Online (AJOL)

    Expanding Agricultural and Rural Extension Roles for Sustainable Extension ... privatization of the public sector of national economies of developing nations has ... include marketing extension, non-farm rural micro enterprise development, ...

  11. Virginia Bioinformatics Institute to expand cyberinfrastructure education and outreach project

    OpenAIRE

    Whyte, Barry James

    2008-01-01

    The National Science Foundation has awarded the Virginia Bioinformatics Institute at Virginia Tech $918,000 to expand its education and outreach program in Cyberinfrastructure - Training, Education, Advancement and Mentoring, commonly known as the CI-TEAM.

  12. Remedial Action Plan for Expanded Bioventing System Facility 6454

    National Research Council Canada - National Science Library

    1996-01-01

    This draft remedial action plan (RAP) presents the scope for an expanded bioventing system for in situ treatment of fuel-contaminated soils at Site 6454 at Vandenberg Air Force Base (AFB), California...

  13. Expandable Cryogenic Tankage for On Orbit Depot Storage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed expandable depot storage tanks would make it possible to have an on-orbit tank larger in volume than any existing or planned launch vehicles. The size...

  14. Expanding Business Opportunities for African Youth in Agricultural ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Expanding Business Opportunities for African Youth in Agricultural Value ... sector actors who can help commercialize them and achieve large-scale impacts. ... CultiAF supports research to achieve long-term food security in Eastern and ...

  15. Scaling up: Expanding the impact of food security and nutrition ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-10-06

    Oct 6, 2016 ... IDRC invests in applied research projects to develop and test ... These solutions are products, technologies, methods, and practices with the ... The social business is expanding from the 55 franchises currently serving 25,000 ...

  16. Environmental assessment, expanded Ponnequin wind energy project, Weld County, Colorado

    International Nuclear Information System (INIS)

    1999-02-01

    The US Department of Energy (DOE) has considered a proposal from the State of Colorado, Office of Energy Conservation (OEC), for funding construction of the Expanded Ponnequin Wind Project in Weld County, Colorado. OEC plans to enter into a contracting arrangement with Public Service Company of Colorado (PSCo) for the completion of these activities. PSCo, along with its subcontractors and business partners, are jointly developing the Expanded Ponnequin Wind Project. The purpose of this Final Environmental Assessment (EA) is to provide DOE and the public with information on potential environmental impacts associated with the Expanded Ponnequin Wind Energy Project. This EA, and public comments received on it, were used in DOE's deliberations on whether to release funding for the expanded project under the Commercialization Ventures Program

  17. Some design features of CO2 swing piston expander

    International Nuclear Information System (INIS)

    Guan Haiqing; Ma Yitai; Li Minxia

    2006-01-01

    CO 2 is a potential substitute for synthesized refrigerants with favorable environmental properties. To improve the coefficient of performance (COP) of CO 2 heat pump systems, a swing piston expander prototype has been developed for replacing the throttling valve based on the thermodynamic analysis of the operating conditions of a CO 2 transcritical cycle. The measures on reducing the loss of friction and leakage are paramount important to improve the efficiency of the expander. The performance of the CO 2 swing expander prototype was actually tested in a CO 2 transcritical cycle water-to-water heat pump test rig, and the test results illustrate that the isentropic efficiency of the prototype can be more than 28% when running steadily and up to a maximum of about 44%. Some operating characteristics of the swing piston expander are presented according to the analysis of the test results

  18. Nitrogen expander cycles for large capacity liquefaction of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun [Hong Ik University, Department of Mechanical Engineering, Seoul, 121-791 (Korea, Republic of); Choe, Kun Hyung [Korea Gas Corporation, Incheon, 406-130 (Korea, Republic of)

    2014-01-29

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity.

  19. Nitrogen expander cycles for large capacity liquefaction of natural gas

    Science.gov (United States)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun; Choe, Kun Hyung

    2014-01-01

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity.

  20. Nitrogen expander cycles for large capacity liquefaction of natural gas

    International Nuclear Information System (INIS)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun; Choe, Kun Hyung

    2014-01-01

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity

  1. Environmental assessment, expanded Ponnequin wind energy project, Weld County, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-02-01

    The US Department of Energy (DOE) has considered a proposal from the State of Colorado, Office of Energy Conservation (OEC), for funding construction of the Expanded Ponnequin Wind Project in Weld County, Colorado. OEC plans to enter into a contracting arrangement with Public Service Company of Colorado (PSCo) for the completion of these activities. PSCo, along with its subcontractors and business partners, are jointly developing the Expanded Ponnequin Wind Project. The purpose of this Final Environmental Assessment (EA) is to provide DOE and the public with information on potential environmental impacts associated with the Expanded Ponnequin Wind Energy Project. This EA, and public comments received on it, were used in DOE`s deliberations on whether to release funding for the expanded project under the Commercialization Ventures Program.

  2. Endovascular therapy of carotid stenosis with self-expandable stent

    International Nuclear Information System (INIS)

    Liu Jianmin; Huang Qinghai; Hong Bo; Xu Yi; Zhao Wenyuan; Zhang Yongwei; Zhang Long; Zhou Xiaoping

    2002-01-01

    Objective: To summarize the experience of endovascular treatment of carotid stenosis with expandable stents. Methods: Fifty-two patients with carotid stenosis who experienced repeated transient ischemic attacks or cerebral infarction were admitted to our hospital. The stenosis was pre-expanded with undetachable balloon, and self-expandable stents were implanted across the stenosis. A balloon catheter was used to further expand stents in 29 patients. Results: The stent was accurately implanted, and total disappearance of stenosis was obtained in 34 patients, the degree of stenosis reduced more than 90% in 16 patients, and more than 70% in 2 patients. The patients recovered well and no complications related to the procedure occurred. None experienced TIA or infarction postoperatively in 52 cases and follow-up imaging in 19 patients (6 - 12 months) demonstrated no restenosis. Conclusion: Endovascular stenting may be a safe and valid choice for the treatment of extracranial carotid stenosis

  3. Expanding the Visibility of Women's Work: Policy Implications.

    Science.gov (United States)

    Messias, DeAnne K. Hilfinger; Regev, Hanna; Im, Eun-Ok; Spiers, Judith A.; Van, Paulina; Meleis, Afaf Ibrahim

    1997-01-01

    Social conceptualization and media images of women's work affect health and social policy formation. Nurses can expand the visibility of women's work and promote gender-sensitive policies within and outside the profession. (SK)

  4. Expanded-boundary approach to impurity control in tokamaks

    International Nuclear Information System (INIS)

    Ohyabu, N.

    1981-01-01

    It is proposed to expand the outermost flux surfaces in tokamaks to divert the heat flux emerging from the plasma core. The expanded flux surfaces provide a large volume for radiative cooling. The radiative power at the boundary is enhanced by the effects of plasma flow as well as by a volumetric factor, and the resultant edge cooling and reduced heat load on the limiter may significantly retard impurity generation. Furthermore, it seems to be compatible with reactor engineering requirements. (author)

  5. Self-Expanding, Tough Biodegradable Elastomers for Wound Stasis

    Science.gov (United States)

    2015-08-06

    the civilian setting, with no effective therapies available at point of injury. We previously reported that a self- expanding polyurethane foam...setting, with no effective therapies available at point of injury. We previously reported that a self-expanding polyurethane foam significantly...care in accor- dance with the Guide of the Care and Use of Laboratory Ani- mals (Health, 2011 #17). 2.2. Instrumentation and monitoring All swine (n

  6. Solid expandable systems put deepwater targets within reach

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Roca, Eduardo [Enventure Global Technology L.L.C., Houston, TX (United States). Latin America; Fristch, Jerry [Enventure Global Technology L.L.C., Houston, TX (United States)

    2008-07-01

    Enabling technologies that take drilling operations to deeper objectives have made a significant impact on the practicality of many projects, especially deep water offshore targets. Increasing vertical depth and lateral reach requires adequate hole size to attain the desired objectives of the well bore. Solid expandable technology can maintain and retain hole size to address both the physical limitations and the economic feasibility of deep water operations. With each and every casing point, the potential for adequate hole size at total depth (TD) decreases. Solid expandable open hole liners and single-diameter systems reduce and eliminate, respectively, the well bore tapering that dictates hole size at TD and subsequent completion size. Successful mitigation of this tapering, whether through the entire well bore or through select zones, enables operators to gain access to previously unreachable reserves. Solid expandable systems have proven to be reliable and effective with over 1,000 installations in a myriad of conditions and environments worldwide. To date, over 115 of those applications have been in deep water environments. The current operating envelope for solid expandable systems include the deepest installation at {approx}28,750 ft (8,763 m) and the longest at 6,867 ft (2,083 m) in water depth over 3,150 ft (960 m). This record-length application consisted of an open hole liner installed and expanded in a single run. This paper will discuss the effectiveness of solid expandable systems in deep water operations and how the technology brings value to offshore projects especially when planned into the initial design. Case histories will be used to further illustrate the features, advantages, and benefits of expandable technology. In addition, this paper will examine the state of the solid expandable technology and its continuing evolution to provide even more drilling solutions. (author)

  7. Ecological and evolutionary processes at expanding range margins

    OpenAIRE

    Thomas, C.D.; Bodsworth, E.J.; Wilson, R.J.; Simmons, A.D.; Davies, Z.G.; Musche, M.; Conradt, L.

    2001-01-01

    Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded\\ud rapidly in association with recent climate warming3±10. We examined four insect species that have expanded their geographical\\ud ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety ...

  8. The motion of an isolated gas group in expanding universe

    International Nuclear Information System (INIS)

    Zhang Banggu

    1993-01-01

    The contraction of an isolated gas group in the expanding universe has been discussed. It is found that in addition to the contracted conditions of the static isolated gas group, the initial gas group is straticulate statistical uniform and the initial radius is larger than a critical value D γ -1 , the contracted conditions of expanding case also include that the Hubble constant H is smaller than a constant D t

  9. Free-piston reciprocating cryogenic expander utilizing phase controller

    Science.gov (United States)

    Cha, Jeongmin; Park, Jiho; Kim, Kyungjoong; Jeong, Sangkwon

    2017-02-01

    In a free-piston expander which eliminates mechanical linkages, a prescribed behaviour of the free-piston movement is the key to an expander performance. In this paper, we have proposed an idea of reducing complexity of the free-piston expander. It is to replace both multiple solenoid valves and reservoirs that are indispensable in a previous machine with a combination of a single orifice-reservoir assembly. It functions as a phase controller like that of a pulse tube refrigerator so that it generates time-delay of pressure variation between the warm-end and the reservoir resulting in the intended expansion of the cold-end volume down to the pre-set reservoir pressure. The modeling of this unique free-piston reciprocating expander utilizing phase controller is developed to understand and predict the performance of the new-type expander. Additionally, the operating parameters are analysed at the specified conditions to enable one to develop a more efficient free-piston type cryogenic expander.

  10. Chronic expanding hematoma in the retroperitoneal space: a case report

    Science.gov (United States)

    2013-01-01

    Background Chronic expanding hematoma is a rare condition that develops after surgery, trauma, or injury. It can also develop at any location in the body in the absence of trauma. Clinical findings and various diagnostic imaging modalities can aid in the differential diagnosis of this condition. In general, hematomas are naturally reabsorbed and rarely cause serious problems. However, hematomas that develop slowly without a history of trauma, surgery, or bleeding disorders could be difficult to differentiate from soft tissue neoplasms. In the present case, we describe a patient, without any history or physical evidence of trauma, who exhibited a large chronic expanding hematoma in the retroperitoneal space that resulted in hydronephrosis because of the pressure exerted on the left ureter. Case presentation A 69-year-old man presented to our hospital with a swollen lesion in the left flank. A mass, 19 cm in diameter, was detected in the retroperitoneal space by computed tomography. We suspected the presence of a chronic expanding hematoma, soft tissue tumor, or left renal artery aneurysm. Surgical treatment was performed. However, postoperative histopathological examination indicated that the mass was a nonmalignant chronic expanding hematoma. No recurrence was observed during a 2-year follow-up period. Conclusion In patients without a history of trauma who present slowly growing masses, the differential diagnosis should include chronic expanding hematoma in addition to cysts and soft tissue tumors. Moreover, the use of magnetic resonance imaging and computed tomography is essential to differentiate between chronic expanding hematoma and soft tissue tumors. PMID:24237992

  11. Evaluation of the stiffness characteristics of rapid palatal expander screws

    Directory of Open Access Journals (Sweden)

    Luca Lombardo

    2016-11-01

    Full Text Available Abstract Background The aim of this study is to evaluate the mechanical properties of the screws used for rapid expansion of the upper jaw. Methods Ten types of expansion screw were assessed, seven with four arms: Lancer Philosophy 1, Dentaurum Hyrax Click Medium, Forestadent Anatomic Expander type “S”, Forestadent Anatomic Expander type “S” for narrow palates, Forestadent Memory, Leone A 2620-10 with telescopic guide, and Leone A 0630-10 with orthogonal arms; and three with two arms: Dentaurum Variety S.P., Target Baby REP Veltri, and Leone A 362113. A test expander with the mean dimensions taken from measurements on a sample of 100 expanders was constructed for each screw. The test expanders were connected to the supports of an Instron 4467 (Instron Corp., USA mechanical testing machine equipped with a 500 N load cell, and the compression force exerted after each activation was measured. The mean forces expressed by the two- and four-arm expanders were then compared. Results After five activations, the forces expressed by the two-arm devices were double than those expressed by the four-arm devices on average (224 ± 59.9 N vs. 103 ± 32.9 N, and such values remained high after subsequent activations. Conclusions The expanders tested demonstrated stiffness characteristics compatible with opening of the palatine sutures in pre-adolescent patients. The stiffness of such devices can be further increased during the construction phase.

  12. Strength analysis of expandable tubulars for well applications

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, A.C.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Fonseca, C.E. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Netto, T.A. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)

    2008-07-01

    Solid expandable tube technology has many advantages when compared to conventional wells. The expansion of tubes in situ allows developing reserves in many of the challenging scenarios found in oil industry, as pre-salt layer, HPHT wells, deep reservoirs, or ultra-deep water. Besides, this procedure has good compatibility with directional and horizontal wells and facilitates side-tracks operations. Although the expansion of tubes is very attractive, a better understanding of its influence on the tube mechanical strength is necessary. In this work, experimental tests and numerical analyses were performed in order to determine the effect of parameters such as diameter-to-thickness ratio and expansion rate on the collapse resistance of expandable tubes. An experimental apparatus was designed and built to reproduce full-scale tube expansion. Three 2 meter long specimens were expanded 10% their original diameters and subjected to hydrostatic pressure inside a vessel until collapse. Three non-expanded tubes were also tested for comparison. At the same time, non-linear numerical models were developed using the finite element method. After calibration, they were used to further analyze the mechanical behavior of solid expandable tubes and the influence of expansion on its resistance against collapse. (author)

  13. Numerical simulation of a twin screw expander for performance prediction

    Science.gov (United States)

    Papes, Iva; Degroote, Joris; Vierendeels, Jan

    2015-08-01

    With the increasing use of twin screw expanders in waste heat recovery applications, the performance prediction of these machines plays an important role. This paper presents a mathematical model for calculating the performance of a twin screw expander. From the mass and energy conservation laws, differential equations are derived which are then solved together with the appropriate Equation of State in the instantaneous control volumes. Different flow processes that occur inside the screw expander such as filling (accompanied by a substantial pressure loss) and leakage flows through the clearances are accounted for in the model. The mathematical model employs all geometrical parameters such as chamber volume, suction and leakage areas. With R245fa as working fluid, the Aungier Redlich-Kwong Equation of State has been used in order to include real gas effects. To calculate the mass flow rates through the leakage paths formed inside the screw expander, flow coefficients are considered as constant and they are derived from 3D Computational Fluid Dynamic calculations at given working conditions and applied to all other working conditions. The outcome of the mathematical model is the P-V indicator diagram which is compared to CFD results of the same twin screw expander. Since CFD calculations require significant computational time, developed mathematical model can be used for the faster performance prediction.

  14. Expanded tenses in the old English orosius a syntactic strengthening*

    Directory of Open Access Journals (Sweden)

    Frančiška Trobevšek Drobnak

    1990-12-01

    Full Text Available The present chapter reports the investigation into certain aspects of the periphrastic construction to be +present participle (e.g. NE: "he is teaching"; OE. "he is laerende" viewed as an example of a syntactic strengthening. The construc­ tion is usually referred to as "continuous tenses/form" or "progressive tenses/form", whereas Nickel (1966 uses "expanded form". Coming closest to this latter term, the "expanded tenses" employed here seems a convenient label for two reasons: a  the use of expanded tenses is not restricted to the expression of verbal aspect (Aspekt or mode of verbal action (Aktionsart, which is implied by the use of either the term "continuous  tenses/form" or the term "progressive tenses/form"; b  the expanded tenses are integrated into the English tense system, in the sense that they can be substituted  with the respective non-expanded tenses without any change in the syntax of the clause, e.g.

  15. Self-expanding/shrinking structures by 4D printing

    Science.gov (United States)

    Bodaghi, M.; Damanpack, A. R.; Liao, W. H.

    2016-10-01

    The aim of this paper is to create adaptive structures capable of self-expanding and self-shrinking by means of four-dimensional printing technology. An actuator unit is designed and fabricated directly by printing fibers of shape memory polymers (SMPs) in flexible beams with different arrangements. Experiments are conducted to determine thermo-mechanical material properties of the fabricated part revealing that the printing process introduced a strong anisotropy into the printed parts. The feasibility of the actuator unit with self-expanding and self-shrinking features is demonstrated experimentally. A phenomenological constitutive model together with analytical closed-form solutions are developed to replicate thermo-mechanical behaviors of SMPs. Governing equations of equilibrium are developed for printed structures based on the non-linear Green-Lagrange strain tensor and solved implementing a finite element method along with an iterative incremental Newton-Raphson scheme. The material-structural model is then applied to digitally design and print SMP adaptive lattices in planar and tubular shapes comprising a periodic arrangement of SMP actuator units that expand and then recover their original shape automatically. Numerical and experimental results reveal that the proposed planar lattice as meta-materials can be employed for plane actuators with self-expanding/shrinking features or as structural switches providing two different dynamic characteristics. It is also shown that the proposed tubular lattice with a self-expanding/shrinking mechanism can serve as tubular stents and grippers for bio-medical or piping applications.

  16. Theoretical investigation of flash vaporisation in a screw expander

    Science.gov (United States)

    Vasuthevan, Hanushan; Brümmer, Andreas

    2017-08-01

    In the present study flash vaporisation of liquid injection in a twin screw expander for a Trilateral Flash Cycle (TFC) is examined theoretically. The TFC process comprises a pressure increase in the working fluid, followed by heating the liquid close to boiling point. The hot liquid is injected into the working chamber of a screw expander. During this process the pressure of the liquid drops below the saturation pressure, while the temperature of the liquid remains virtually constant. Hence the liquid is superheated and in a metastable state. The liquid jet seeks to achieve a stable state in thermodynamic equilibrium and is therefore partially vaporised. This effect is referred to as flash vaporisation. Accordingly, a two-phase mixture, consisting of vapour and liquid, exists in the working chamber. Thermodynamic simulations were carried out using water as the working fluid for representative screw expander geometry. The simulations presented are performed from two different aspects during the filling process of a screw expander. The first case is the vaporisation of the injected liquid in a state of thermodynamic equilibrium, whereby the two-phase mixture is treated entirely as a compressible and homogeneous gas. The second case considers flashing efficiency. It describes the quantity of flashed vapour and consists of a liquid and vapour domain. Both models are compared and analysed with respect to the operational behaviour of a screw expander.

  17. Expandable Total Humeral Replacement in a Child with Osteosarcoma

    Directory of Open Access Journals (Sweden)

    Eric R. Henderson

    2015-01-01

    Full Text Available Case. A right-handed 8-year-old female patient presented with a conventional, high-grade osteosarcoma involving her right humerus; through-shoulder amputation was recommended. After consultation, total humerus resection with expandable, total humeral endoprosthesis reconstruction was performed with a sleeve to encourage soft-tissue ingrowth. At three-year follow-up she has received one lengthening procedure and her functional scores are excellent. Conclusion. Total humeral resection and replacement in the pediatric population are rare and although early reports of expandable total humeral endoprosthesis outcomes demonstrate high failure rates, this patient’s success indicates that expandable total humeral replacement is a viable option.

  18. Esophagorespiratory fistula: treatment with self-expanding covered stent

    International Nuclear Information System (INIS)

    Zang Jian; Dou Yongchong; Wang Zheng; Kong Jian

    2002-01-01

    Objective: To evaluate self-expanding covered stent in the management of esophagorespiratory fistula. Methods: A self-expanding esophageal covered stent was implanted under fluoroscopic guidance in 13 patients with esophagorespiratory fistula. In this series patients aged 31-73 years (60.2 years in average). All patients had a pre-procedure fast of 6-41 days (17.3 days in average), in which 12 patients had pulmonary infection. Results: All fistulas were excluded and swallowing function was restored. No stend-related complication was observed. Pulmonary infection was managed in 10 patients out of 13. The mean survived time was 33.3 wks (1-178 wks) in follow-up. Conclusion: Covered self-expanding stent implantation is a safe and effective treatment of ERF

  19. Can microcarrier-expanded chondrocytes synthesize cartilaginous tissue in vitro?

    Science.gov (United States)

    Surrao, Denver C; Khan, Aasma A; McGregor, Aaron J; Amsden, Brian G; Waldman, Stephen D

    2011-08-01

    Tissue engineering is a promising approach for articular cartilage repair; however, it is challenging to produce adequate amounts of tissue in vitro from the limited number of cells that can be extracted from an individual. Relatively few cell expansion methods exist without the problems of de-differentiation and/or loss of potency. Recently, however, several studies have noted the benefits of three-dimensional (3D) over monolayer expansion, but the ability of 3D expanded chondrocytes to synthesize cartilaginous tissue constructs has not been demonstrated. Thus, the purpose of this study was to compare the properties of engineered cartilage constructs from expanded cells (monolayer and 3D microcarriers) to those developed from primary chondrocytes. Isolated bovine chondrocytes were grown for 3 weeks in either monolayer (T-Flasks) or 3D microcarrier (Cytodex 3) expansion culture. Expanded and isolated primary cells were then seeded in high density culture on Millicell™ filters for 4 weeks to evaluate the ability to synthesize cartilaginous tissue. While microcarrier expansion was twice as effective as monolayer expansion (microcarrier: 110-fold increase, monolayer: 52-fold increase), the expanded cells (monolayer and 3D microcarrier) were not effectively able to synthesize cartilaginous tissue in vitro. Tissues developed from primary cells were substantially thicker and accumulated significantly more extracellular matrix (proteoglycan content: 156%-292% increase; collagen content: 70%-191% increase). These results were attributed to phenotypic changes experienced during the expansion phase. Monolayer expanded chondrocytes lost their native morphology within 1 week, whereas microcarrier-expanded cells were spreading by 3 weeks of expansion. While the use of 3D microcarriers can lead to large cellular yields, preservation of chondrogenic phenotype during expansion is required in order to synthesize cartilaginous tissue.

  20. Esophagojejunal anastomotic leak managed with self expandable metallic stent

    Directory of Open Access Journals (Sweden)

    Arvind Madurandagam Annapillai

    2013-01-01

    Full Text Available Esophagealjejunal anastomotic leak after gastrectomy is a serious surgical emergency with high mortality. This report describes a 57-year-old male with esophagojejunal anastomotic leak following total gastrectomy for gastric cancer and was managed successfully with self-expandable metallic stent. To our knowledge this is the first such report from India. This case report highlights the need of interdisciplinary coordination in managing this difficult clinical situation. Endotherapy with self-expandable metallic stent (SEM provided twin benefits of improving respiratory embarrassment and the joy of eating. Therapy of such difficult cases must be individualized; however, and SEM stent usage is a viable option

  1. Functional Self-Expandable Metal Stents in Biliary Obstruction

    Science.gov (United States)

    Kwon, Chang-Il; Ko, Kwang Hyun; Hahm, Ki Baik

    2013-01-01

    Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories. PMID:24143314

  2. Scalar-Tensor Black Holes Embedded in an Expanding Universe

    Science.gov (United States)

    Tretyakova, Daria; Latosh, Boris

    2018-02-01

    In this review we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on a black hole, embedded in an expanding universe, describing both cosmological and astrophysical scales. We show that in scalar-tensor gravity it is quite common that the local geometry is isolated from the cosmological expansion, so that it does not backreact on the black hole metric. We try to extract common features of scalar-tensor black holes in an expanding universe and point out the gaps that must be filled.

  3. Dissipation and fluctuation of quantum fields in expanding universes

    International Nuclear Information System (INIS)

    Morikawa, M.

    1990-01-01

    A stochastic dynamics of a long-wavelength part of a scalar field in an expanding universe is derived by using the influence functional method. Dissipation as well as fluctuation are derived for general parameters: a mass, a coupling to the scalar curvature, and a cutoff scale parameter. A dissipation-fluctuation relation is found with a temperature which is proportional to the Hawking temperature, but system dependent. The method is further applied to an expanding universe with a power law and yields the dispersion which agrees with that obtained by the regularization method. The back reaction to the background de Sitter space itself is also obtained

  4. Scalar-Tensor Black Holes Embedded in an Expanding Universe

    Directory of Open Access Journals (Sweden)

    Daria Tretyakova

    2018-02-01

    Full Text Available In this review, we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on black holes, embedded in an expanding universe, describing both cosmological and astrophysical scales. We show that in scalar-tensor gravity it is quite common that the local geometry is isolated from the cosmological expansion, so that it does not backreact on the black hole metric. We try to extract common features of scalar-tensor black holes in an expanding universe and point out the issues that are not fully investigated.

  5. On the Propagation of Light in an Expanding Universe

    Directory of Open Access Journals (Sweden)

    Yuri Heymann

    2013-07-01

    Full Text Available The equation of the propagation of light in an expanding Universe is derived based on the definition of comoving distances. A numerical method is proposed to solve this equation jointly with the Friedmann equation. As the equation of the propagation of light in an expanding Universe defines a horizon of the visible Universe, this puts a constraint on cosmological models in order to be consistent with an upper limit for redshifts observed from galaxies. This puzzle is challenging current expansionist cosmological models.

  6. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    International Nuclear Information System (INIS)

    Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

    2015-01-01

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

  7. Hubble Diagram Test of Expanding and Static Cosmological Models: The Case for a Slowly Expanding Flat Universe

    Directory of Open Access Journals (Sweden)

    Laszlo A. Marosi

    2013-01-01

    Full Text Available We present a new redshift (RS versus photon travel time ( test including 171 supernovae RS data points. We extended the Hubble diagram to a range of z = 0,0141–8.1 in the hope that at high RSs, the fitting of the calculated RS/ diagrams to the observed RS data would, as predicted by different cosmological models, set constraints on alternative cosmological models. The Lambda cold dark matter (ΛCDM, the static universe model, and the case for a slowly expanding flat universe (SEU are considered. We show that on the basis of the Hubble diagram test, the static and the slowly expanding models are favored.

  8. Expanded-bed chromatography in primary protein purification.

    Science.gov (United States)

    Anspach, F B; Curbelo, D; Hartmann, R; Garke, G; Deckwer, W D

    1999-12-31

    Chromatography in stable expanded beds enables proteins to be recovered directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids. The general performance of an expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles in the column. However, optimal operating conditions are more restricted than in a packed bed due to the dependence of bed expansion on the size and density of the adsorbent particles as well as the viscosity and density of the feedstock. The feedstock composition may become the most limiting restriction owing to interactions of adsorbent particles with cell surfaces, DNA and other substances, leading to their aggregation and consequently to bed instabilities and channeling. Despite these difficulties, expanded-bed chromatography has found widespread applications in the large scale purification of proteins from mammalian cell and microbial feedstocks in industrial bioprocessing. The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

  9. Interpreting and Expanding Confucius' Golden Mean through Neutrosophic Tetrad

    Directory of Open Access Journals (Sweden)

    Fu Yuhua

    2016-03-01

    Full Text Available Neutrosophy is a new branch of philosophy that studies the origin, nature, and scope of neutralities, as well as their interactions with different ideational spectra. There are many similarities between The Golden Mean and Neutrosophy. Chinese and international scholars need to toil towards expanding and developing The Golden Mean, towards its "modernization" and "globalization".

  10. DEMONSTRATION OF PACKAGING MATERIALS ALTERNATIVES TO EXPANDED POLYSTYRENE

    Science.gov (United States)

    This report represents the second demonstration of cleaner technologies to support the goals of the 33/50 Program under the EPA Cooperative Agreement No. CR-821848. The report presents assessment results of alternative packaging materials which could potentially replace expanded...

  11. Expanded porphyrins as third order non-linear optical materials ...

    Indian Academy of Sciences (India)

    WINTEC

    function correlations ... An understanding of the structure–function corre- lations of these expanded porphyrins is an important first step for ... where χ (2) and χ (3) are the quadratic χ (2) (first- order) and χ (3) cubic (second-order) susceptibilities.

  12. Expanding horizons. Integrating environmental health in occupational health nursing.

    Science.gov (United States)

    Rogers, B; Cox, A R

    1998-01-01

    1. Environmental hazards are ubiquitous. Many exist in the workplace or occur as a result of work process exposures. 2. Environmental health is a natural component of the expanding practice of occupational health nursing. 3. AAOHN's vision for occupational and environmental health will continue to set the standard and provide leadership in the specialty.

  13. Expanding Possibilities through Metaphor: Breaking Biases to Improve Crisis Management

    Science.gov (United States)

    Cirka, Carol C.; Corrigall, Elizabeth A.

    2010-01-01

    In this article, we demonstrate that an exercise using metaphors to overcome cognitive biases helped students to proactively imagine and prepare for an expanded set of potential crises. The exercise complements traditional textbook approaches to crisis management and incorporates creativity skill building in a realistic context. Learning outcomes…

  14. Absorption of continuum radiation in a resonant expanding gaseous sphere

    International Nuclear Information System (INIS)

    Shaparev, N Y

    2014-01-01

    The paper deals with absorption of external continuum radiation in a self-similarly expanding gaseous sphere. Frequency probability and integral probability of radiation absorption in the resonance frequency range are determined depending on the expansion velocity gradient and thickness of the optical medium. It is shown that expansion results in a reduced optical thickness of the medium and enhanced integral absorption. (paper)

  15. Expanding the Oral Hygiene Curriculum in a Nursing Program.

    Science.gov (United States)

    Briggs, Susan; Griego, Elizabeth

    A program was implemented to expand the curriculum materials within the Licensed Practical Nursing (LPN) Program at Clark County Community College (CCCC) which relate to oral hygiene care for the hospital patient. The instructional materials included a video tape and a written instructional packet which were researched, prepared, and presented by…

  16. Expanding Gerontology Enrollments: Successful Results of an Innovative Outreach Program

    Science.gov (United States)

    Reynolds, Sandra L.; Haley, William E.; Hyer, Kathryn

    2007-01-01

    As state budget allocations for higher education decrease, "specialty" programs such as gerontology must continually demonstrate their productivity. State and private universities increasingly rely on student credit hours (SCH) or tuition generated, which is making it difficult for many gerontology programs to expand. The School of Aging Studies…

  17. Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders

    NARCIS (Netherlands)

    Peck, C.C.; Goulet, J-P; Lobbezoo, F.; Schiffman, E.L.; Alstergren, P.; Anderson, G.C.; De Leeuw, R.; Jensen, R.; Michelotti, A.; Ohrbach, R.; Petersson, A.; List, T.

    2014-01-01

    There is a need to expand the current temporomandibular disorders' (TMDs) classification to include less common but clinically important disorders. The immediate aim was to develop a consensus-based classification system and associated diagnostic criteria that have clinical and research utility for

  18. The effectiveness of the Expanded Public Works Programme on job ...

    African Journals Online (AJOL)

    The effectiveness of the Expanded Public Works Programme on job creation: a look at a South African ... Open Access DOWNLOAD FULL TEXT ... This paper reports of a study that examined how the eThekwini Municipality's EPWP has been ...

  19. Expanding Library Support of Faculty Research: Exploring Readiness

    Science.gov (United States)

    Brown, Jeanne M.; Tucker, Cory

    2013-01-01

    The changing research and information environment requires a reexamination of library support for research. This study considers research-related attitudes and practices to identify elements indicating readiness or resistance to expanding the library's role in research support. A survey of faculty conducted at the University of Nevada Las Vegas…

  20. Tear Gas, Expanding Bullets and Plain-Clothed Personnel

    DEFF Research Database (Denmark)

    Wiesener, Cornelius Rust

    2017-01-01

    This article examines the interplay between human rights law and humanitarian law in relation to riot control agents (such as tear gas), expanding bullets and plain-clothed forces. While outlawed under humanitarian law, they are widely used by police in peace time and not subject to similar bans...

  1. Crowd Around: Expanding Your Donor Pool with Crowdfunding

    Science.gov (United States)

    Jarrell, Andrea

    2013-01-01

    At most institutions, annual fund-giving is down. Crowdfunding sites allow people with a great idea or worthy cause to bypass traditional funding methods and take their case directly to web-savvy investors and donors. This article describes how higher education institutions are expanding their donor pool through such crowdfunding sites as USEED,…

  2. On the elusive crystal structure of expanded austenite

    DEFF Research Database (Denmark)

    Brink, Bastian; Ståhl, Kenny; Christiansen, Thomas Lundin

    2017-01-01

    No consistent structural description exists for expanded austenite that accurately accounts for the hkl-dependent peak shifts and broadening observed in diffraction experiments. The best available description for homogeneous samples is a face-centered cubic lattice with stacking faults. Here Deby...

  3. Lattice expansion of carbon-stabilized expanded austenite

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The lattice parameter of expanded austenite was determined as a function of the content of interstitially dissolved carbon in homogeneous, carburized thin stainless steel foils. For the first time this expansion of the face-centered cubic lattice is determined on unstrained austenite. It is found...

  4. Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders

    DEFF Research Database (Denmark)

    Peck, C C; Goulet, J-P; Lobbezoo, F

    2014-01-01

    There is a need to expand the current temporomandibular disorders' (TMDs) classification to include less common but clinically important disorders. The immediate aim was to develop a consensus-based classification system and associated diagnostic criteria that have clinical and research utility f...

  5. Validation of the Chinese Expanded Euthanasia Attitude Scale

    Science.gov (United States)

    Chong, Alice Ming-Lin; Fok, Shiu-Yeu

    2013-01-01

    This article reports the validation of the Chinese version of an expanded 31-item Euthanasia Attitude Scale. A 4-stage validation process included a pilot survey of 119 college students and a randomized household survey with 618 adults in Hong Kong. Confirmatory factor analysis confirmed a 4-factor structure of the scale, which can therefore be…

  6. Enrichment in Massachusetts Expanded Learning Time (ELT) Schools. Issue Brief

    Science.gov (United States)

    Caven, Meghan; Checkoway, Amy; Gamse, Beth; Luck, Rachel; Wu, Sally

    2012-01-01

    This brief highlights key information about enrichment activities, which represent one of the main components of the Massachusetts Expanded Learning Time (ELT) initiative. Over time, the ELT initiative has supported over two dozen schools across the Commonwealth. A comprehensive evaluation of the ELT initiative found that implementation of the…

  7. Diaspora, Migration, and Globalization: Expanding the Discourse of Adult Education

    Science.gov (United States)

    Alfred, Mary V.

    2015-01-01

    This article explores how notions of diaspora, migration, and globalization intersect to inform identities and social realities of those who leave their homeland and resettle in other nations. It calls for expanding the discourse of adult education to incorporate critical studies of the diaspora to make visible the inequality and imbalance of…

  8. Stability of a Bubble Expanding and Translating Through an Inviscid ...

    Indian Academy of Sciences (India)

    A bubble expands adiabatically and translates in an incompressible and inviscid liquid. We investigate the number of equilibrium points of the bubble and the nature of stability of the bubble at these points. We find that there is only one equilibrium point and the bubble is stable there.

  9. The Expanded Food and Nutrition Education Program (EFNEP)

    Science.gov (United States)

    National Institute of Food and Agriculture, 2010

    2010-01-01

    Obesity, poor health, and limited physical activity are major health concerns. The Expanded Food and Nutrition Education Program (EFNEP) improves the health and well-being of limited resource families and youth. Additionally, EFNEP leads to public savings. Research shows that better health is associated with reduced health care costs, less…

  10. A self-adjusting expandable GPS collar for male elk

    Science.gov (United States)

    Brian L. Dick; Scott L. Findholt; Bruce K. Johnson

    2013-01-01

    It is a challenge to use collars on male cervids because their neck size can increase substantially during the rut and also because of growth as the animal matures. We describe how to build a self-adjusting expandable collar for yearling or adult male Rocky Mountain elk (Cervus elaphus) to which very high frequency transmitters and global...

  11. Expanding Sex-Role Definitions by Self-Discovery.

    Science.gov (United States)

    Kahn, Sharon E.; Greenberg, Leslie S.

    1980-01-01

    Counselors who stimulate client self-discovery may help these clients experience undeveloped parts of themselves and expand their definitions of themselves and their sex-role possibilities. Stimulation methods actively involve clients in the exploration of sex-role concerns to change restrictive self-concepts. (Author)

  12. Expanded cardiac rehabilitation in socially vulnerable patients with myocardial infarction

    DEFF Research Database (Denmark)

    Hald, Kathrine; Nielsen, Kirsten Melgaard; Nielsen, Claus Vinther

    2018-01-01

    OBJECTIVE: Cardiac rehabilitation (CR) has been shown to reduce cardiovascular risk. A research project performed at a university hospital in Denmark offered an expanded CR intervention to socially vulnerable patients. One-year follow-up showed significant improvements concerning medicine...

  13. Assessing Community Needs for Expanding Environmental Education Programming

    Science.gov (United States)

    Hintz, Carly J.; Lackey, Brenda K.

    2017-01-01

    Based on increased demand for educational programming, leadership at Schmeeckle Reserve, a campus natural area in Stevens Point, WI explored the needs for expanded environmental education efforts. In 2014, a three-phased needs assessment framework was employed to explore educational programming offered in the community. Results from interviews and…

  14. Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Hitoshi; Sakaguchi, Hiroshi; Yoshioka, Tetsuya and others

    1989-02-01

    A double lumen catheter was developed as an apllicator for the remote afterloading (RALS) of /sup 60/Co source for the intracavitary irradiation of an obstructed common bile duct caused by carcinoma of the gallbladder. This was followed by the placement of nylon-covered expandable metallic stents to maintain patency. This combination effectively provided palliation. (author).

  15. New expanded bed adsorbents for the recovery of DNA

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Olander, M. A.; Sondergaard, M.

    2000-01-01

    A 20-40 mum pellicular high density (similar to3.7 g cm(-3)) expanded bed material has been designed for the capture of DNA and other large macromolecules. Anion exchangers fashioned out of these supports exhibited dramatically enhanced DNA binding capacities over commercial anion exchange...

  16. Malignant biliary obstruction: percutaneous use of self-expandable stents

    NARCIS (Netherlands)

    Laméris, J. S.; Stoker, J.; Nijs, H. G.; Zonderland, H. M.; Terpstra, O. T.; van Blankenstein, M.; Schütte, H. E.

    1991-01-01

    A total of 83 self-expandable metallic stents were placed percutaneously in 69 patients for palliation of malignant biliary obstruction. Stent diameter was 1 cm; length, 3.5-10.5 cm. Of the 41 patients with common bile duct obstruction, 27 died 0.2-12 months (median, 3.2 months) after stent

  17. Fire Resistance of Concrete Constructions with Expanded Clay Aggregate

    DEFF Research Database (Denmark)

    Hertz, Kristian Dahl

    2003-01-01

    The paper describes briefly a series of full-scale tests made as documentation for extending the field of application of the reduced cross section method from the structural codes to constructions based on expanded clay aggregate. As a special result the tests verify that slabs with a short ancho...

  18. Browsing Your Virtual Library: The Case of Expanding Universe.

    Science.gov (United States)

    Daniels, Wayne; Enright, Jeanne; Mackenzie, Scott

    1997-01-01

    Describes "Expanding Universe: a classified search tool for amateur astronomy," a Web site maintained by the Metropolitan Toronto Reference Library which uses a modified form of the Dewey Decimal Classification to organize a large file of astronomy hotlinks. Highlights include structure, HTML coding, design requirements, and future…

  19. Gravitational instantons and separation of an expanding Universe

    International Nuclear Information System (INIS)

    Rubakov, V.A.; Tinyakov, P.G.

    1988-01-01

    Instanton, describing the separation of closed small-size classically inflating Universe from the plane Universe, was found in the model of gravitational field, interacting with matter fields. Existence of such instantons provides the possibility of expanding Universe self-birth

  20. Expanding Access to Insurance by the Poor : Policy, Regulation and ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Expanding Access to Insurance by the Poor : Policy, Regulation and Supervision of Micro Insurance. This project aims to facilitate poor people's access to insurance products and services as a means of addressing their vulnerability to risk. It will do so by carrying out case studies in five countries. Potential candidates ...

  1. Dynamical 3-Space: Black Holes in an Expanding Universe

    Directory of Open Access Journals (Sweden)

    Rothall D. P.

    2013-10-01

    Full Text Available Black holes are usually studied without including effects of the expanding universe. However in some recent studies black holes have been embedded in an expanding universe, in order to determine the interplay, if any, of these two dynamical processes. Dynamical 3-space theory contains time independent solutions for black holes, which are spatial in-flows, and separately the time dependent Hubble expansion. This theory has explained numerous puzzles in observational astrophysics and contains 3 constants; G, - which from experimental data turns out to be the fine structure constant, and - which is a small but nonzero distance, possibly a Planck-type length. The Hubble expansion in the dynamical 3-space theory cannot be “switched o”, forcing the study, first, of isolated black holes coexisting with the expanding universe. It is shown that a time dependent black hole and expanding universe solution exists. The nature and implications of these solutions are discussed as they evolve over time. A dynamical network of black holes and induced linking cosmic filaments forming bubble structures is discussed, as a consequence of dynamical 3-space undergoing a dynamical breakdown of homogeneity and isotropy, even in the absence of baryonic matter.

  2. Expanded clinical spectrum of enhanced S-cone syndrome

    NARCIS (Netherlands)

    Yzer, Suzanne; Barbazetto, Irene; Allikmets, Rando; van Schooneveld, Mary J.; Bergen, Arthur; Tsang, Stephen H.; Jacobson, Samuel G.; Yannuzzi, Lawrence A.

    2013-01-01

    New funduscopic findings in patients with enhanced S-cone syndrome (ESCS) may help clinicians in diagnosing this rare autosomal recessive retinal dystrophy. To expand the clinical spectrum of ESCS due to mutations in the NR2E3 gene. Retrospective, noncomparative case series of 31 patients examined

  3. Gravitational Clustering of Galaxies in an Expanding Universe ...

    Indian Academy of Sciences (India)

    2006-12-08

    Dec 8, 2006 ... Abstract. We inquire the phenomena of clustering of galaxies in an expanding universe from a theoretical point of view on the basis of ther- modynamics and correlation functions. The partial differential equation is developed both for the point mass and extended mass structures of a two-point correlation ...

  4. Expanding Doctoral Education in South Africa: Pipeline or Pipedream?

    Science.gov (United States)

    Herman, Chaya

    2011-01-01

    The purpose of this paper is to discuss both the status of the PhD in South Africa and the feasibility of the country's aspiration to increase by fivefold the production of PhDs by 2025. Based on the first empirical studies on doctoral education in South Africa, it argues that in order to move towards this target, an expanded and coordinated…

  5. Operation of an organic Rankine cycle dependent on pumping flow rates and expander torques

    International Nuclear Information System (INIS)

    Yang, Xufei; Xu, Jinliang; Miao, Zheng; Zou, Jinghuang; Yu, Chao

    2015-01-01

    An ORC (organic Rankine cycle) was developed with R123 as the working fluid. The heat capacity is in ∼100 kW. The match between pump and expander is investigated. Lower pump frequencies (f 10 Hz) adapt low expander torques only, and cause unstable flow and pump cavitation for larger expander torques. Ultra-low expander torques generate sufficiently high vapor superheatings to decrease expander efficiencies. Ultra-high expander torques achieve saturation vapor at the expander inlet, causing liquid droplets induced shock wave to worsen expander performance. An optimal range of expander torques exists to have better expander performance. A liquid subcooling of 20 °C is necessary to avoid pump cavitation. Expander powers and efficiencies show parabola shapes versus expander torques, or vapor superheatings at the expander inlet. The optimal vapor superheating is 13 °C. The cavitation mechanisms and measures to avoid cavitation are analyzed. This paper notes the overestimation of ORC performance by equilibrium thermodynamic analysis. Assumptions should be dependent on experiments. Future studies are suggested on organic fluid flow, heat transfer and energy conversion in various components. - Highlights: • The match between pump and expander is investigated. • A liquid subcooling of 20 °C is needed at pump inlet. • A vapor superheating of 13 °C is necessary at expander inlet. • Cavitation in pumps and expanders are analyzed. • The equilibrium thermodynamics overestimate ORC performances.

  6. Using Typography to Expand the Design Space of Data Visualization

    Directory of Open Access Journals (Sweden)

    Richard Brath

    Full Text Available This article is a systematic exploration and expansion of the data visualization design space focusing on the role of text. A critical analysis of text usage in data visualizations reveals gaps in existing frameworks and practice. A cross-disciplinary review including the fields of typography, cartography, and coding interfaces yields various typographic techniques to encode data into text, and provides scope for an expanded design space. Mapping new attributes back to well understood principles frames the expanded design space and suggests potential areas of application. From ongoing research created with our framework, we show the design, implementation, and evaluation of six new visualization techniques. Finally, a broad evaluation of a number of visualizations, including critiques from several disciplinary experts, reveals opportunities as well as areas of concern, and points towards additional research with our framework.

  7. Expanded Endonasal Endoscopic Approach for Resection of an Infrasellar Craniopharyngioma.

    Science.gov (United States)

    Abou-Al-Shaar, Hussam; Blitz, Ari M; Rodriguez, Fausto J; Ishii, Masaru; Gallia, Gary L

    2016-11-01

    Craniopharyngiomas are uncommon benign locally aggressive epithelial tumors mostly located in the sellar and suprasellar regions. An infrasellar origin of these tumors is rare. The authors report a 22-year-old male patient with a purely infrasellar adamantinomatous craniopharyngioma centered in the nasopharynx with extension into the posterior nasal septum, sphenoid sinus, and clivus. Gross total resection was achieved using an expanded endonasal endoscopic transethmoidal, transsphenoidal, transpterygoid, and transclival approach. Follow-up at one year demonstrated no evidence of disease recurrence. Infrasellar craniopharyngioma should be included in the differential diagnosis of sinonasal masses even in the absence of sellar extension. Expanded endonasal endoscopic approaches provide excellent access to and visualization of such lesions and may obviate the need for postoperative radiotherapy when gross total resection is achieved. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Einstein's conversion from his static to an expanding universe

    Science.gov (United States)

    Nussbaumer, Harry

    2014-02-01

    In 1917 Einstein initiated modern cosmology by postulating, based on general relativity, a homogenous, static, spatially curved universe. To counteract gravitational contraction he introduced the cosmological constant. In 1922 Alexander Friedman showed that Albert Einstein's fundamental equations also allow dynamical worlds, and in 1927 Georges Lemaître, backed by observational evidence, concluded that our universe was expanding. Einstein impetuously rejected Friedman's as well as Lemaître's findings. However, in 1931 he retracted his former static model in favour of a dynamic solution. This investigation follows Einstein on his hesitating path from a static to the expanding universe. Contrary to an often advocated belief the primary motive for his switch was not observational evidence, but the realisation that his static model was unstable.

  9. Caudal Regression and Encephalocele: Rare Manifestations of Expanded Goldenhar Complex

    Directory of Open Access Journals (Sweden)

    Gabriella D’Angelo

    2017-01-01

    Full Text Available Oculoauriculovertebral spectrum, or Goldenhar Syndrome, is a condition characterized by variable degrees of uni- or bilateral involvement of craniofacial structures, ocular anomalies, and vertebral defects. Its expressivity is variable; therefore, the term “expanded Goldenhar complex” has been coined. The Goldenhar Syndrome usually involves anomalies in craniofacial structures, but it is known that nervous system anomalies, including encephalocele or caudal regression, may, rarely, occur in this condition. We report two rare cases of infants affected by Goldenhar Syndrome, associated with neural tube defects, specifically caudal regression syndrome and nasal encephaloceles, to underline the extremely complex and heterogeneous clinical features of this oculoauriculovertebral spectrum. These additional particular cases could increase the number of new variable spectrums to be included in the “expanded Goldenhar complex.”

  10. Expanded and combined uncertainty in measurements by GM counters

    International Nuclear Information System (INIS)

    Stankovic, K.; Arandjic, D.; Lazarevic, Dj.; Osmokrovic, P.

    2007-01-01

    This paper deals with possible ways of obtaining expanded and combined uncertainty in measurements for four types of GM counters with a same counter's tube, in cases when the contributors of these uncertainties are cosmic background radiation and induced overvoltage phenomena. Nowadays, as a consequence of electromagnetic radiation, the latter phenomenon is especially marked in urban environments. Based on experimental results obtained, it has been established that the uncertainties of an influenced random variable 'number of pulses from background radiation' and 'number of pulses induced by overvoltage' depend on the technological solution of the counter's reading system and contribute in different ways to the expanded and combined uncertainty in measurements of the applied types of GM counters. (author)

  11. Expanding beyond individualism: Engaging critical perspectives on occupation.

    Science.gov (United States)

    Gerlach, Alison J; Teachman, Gail; Laliberte-Rudman, Debbie; Aldrich, Rebecca M; Huot, Suzanne

    2018-01-01

    Perspectives that individualize occupation are poorly aligned with socially responsive and transformative occupation-focused research, education, and practice. Their predominant use in occupational therapy risks the perpetuation, rather than resolution, of occupational inequities. In this paper, we problematize taken-for-granted individualistic analyses of occupation and illustrate how critical theoretical perspectives can reveal the ways in which structural factors beyond an individual's immediate control and environment shape occupational possibilities and occupational engagement. Using a critically reflexive approach, we draw on three distinct qualitative research studies to examine the potential of critical theorizing for expanding beyond a reliance on individualistic analyses and practices. Our studies highlight the importance of addressing the socio-historical and political contexts of occupation and demonstrate the contribution of critical perspectives to socially responsive occupational therapy. In expanding beyond individualistic analyses of occupation, critical perspectives advance research and practices towards addressing socio-political mediators of occupational engagement and equity.

  12. Basic Study on Engine with Scroll Compressor and Expander

    Science.gov (United States)

    Morishita, Etsuo; Kitora, Yoshihisa; Nishida, Mitsuhiro

    Scroll compressors are becoming popular in air conditioning and refrigeration. This is primarily due to their higher efficiency and low noise/vibration characteristics. The scroll principle can be applied also to the steam expander and the Brayton cycle engine,as shown in the past literature. The Otto cycle spark-ignition engine with a scroll compressor and expander is studied in this report. The principle and basic structure of the scroll engine are explained,and the engine characteristic are calculated based on the idealized cycles and processes. A prototype model has been proposed and constructed. The rotary type engine has always had a problem with sealing. The scroll engine might overcome this shortcoming with its much lower rubbing speed compared to its previous counterparts,and is therefore worth investigating.

  13. Tunneling in expanding Universe: Euclidean and Hamiltonian approaches

    International Nuclear Information System (INIS)

    Goncharov, A.S.; Linde, A.D.

    1986-01-01

    The theory of the false vacuum decay in de Sitter space and in the inflationary Universe, and also the theory of the Universe creation ''from nothing'' are discussed. This explained why tunneling in the inflationary Universe differs from that in de Sitter space and cannot be exactly homogeneous. It is shown that in several important cases the Euclidean approach should be considerably modified or is absolutely inapplicable for the description of tunneling in the expanding Universe and of the process of the quantum creation of the Universe. The Hamiltonian approach to the theory of tunneling in expanding Universe is developed. The results obtained by this method are compared with the results obtained by the Euclidean approach

  14. The expanded "BAT" flap for treatment of male pattern baldness.

    Science.gov (United States)

    Anderson, R D

    1993-11-01

    A new combination of expanded simultaneous transposition and advancement flaps is reported for the treatment of extensive male pattern baldness. Although vertical transposition and parieto-occipital advancement flaps in themselves are not new, their combination and simultaneous bilateral use combined with the use of expansion is new. The advantages of the expanded bilateral advancement transposition flap procedure are presented, along with the technique and results. The results are predictable, providing a more pleasing result, with a natural immediate temporal recession, avoidance of temporal dog-ears, and desirable anterior-superior direction of hair growth. Although flaps do require surgical skill and training, and there are risks and possible complications involved, the results are achieved in a relatively short time compared with grafting techniques. Flaps also provide the advantages of a full and natural hairline contrasted with the sparse look afforded by multiple grafts. The described procedures are very effective and reliable when properly planned and properly executed.

  15. Adipose tissue expandability and the early origins of PCOS.

    Science.gov (United States)

    de Zegher, Francis; Lopez-Bermejo, Abel; Ibáñez, Lourdes

    2009-11-01

    The most prevalent phenotypes of polycystic ovary syndrome (PCOS) are characterized by insulin resistance and androgen excess. The adipose tissue (AT) expandability hypothesis explains the development of insulin resistance in obesity and in cases of AT deficit. In line with this hypothesis, we propose that hyperinsulinemic androgen excess in PCOS is often underpinned by exhaustion of the capacity to expand subcutaneous AT in a metabolically safe way. Such exhaustion might occur when a positive energy imbalance meets a normal fat-storage capacity and/or when a normal energy balance faces a low fat storage capacity. This concept thus explains how PCOS phenotypes might result from obesity, prenatal growth restraint or a genetic lipodystrophy, or, experimentally, from prenatal androgen excess.

  16. Interpreting and Expanding Confucius' Golden Mean through Neutrosophic Tetrad

    OpenAIRE

    Fu, Yuhua

    2015-01-01

    Neutrosophy is a new branch of philosophy that studies the origin, nature, and scope of neutralities, as well as their interactions with different ideational spectra. There are many similarities between The Golden Mean and Neutrosophy. Chinese and international schol-ars need to toil towards expanding and developing The Golden Mean, towards its "modernization" and "globalization". Not only Chinese contemporary popular ideas and methods, but also international contemporary popular ideas and me...

  17. Remarks to the creation of particles in an expanding universe

    International Nuclear Information System (INIS)

    Kreisel, E.

    1976-01-01

    It is shown that one can get spontaneous particle creation in an empty Minkowski-space, if one defines particle-number operator and Hilbert space in a similar way as in publications about particle creation in an expanding universe. Accordingly spontaneous particle creation does not originate in the gravitational field, but is connected with the non-uniqueness of the notion 'particle' and the chosen time-dependent particle- number operator. (author)

  18. Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders.

    Science.gov (United States)

    Peck, C C; Goulet, J-P; Lobbezoo, F; Schiffman, E L; Alstergren, P; Anderson, G C; de Leeuw, R; Jensen, R; Michelotti, A; Ohrbach, R; Petersson, A; List, T

    2014-01-01

    There is a need to expand the current temporomandibular disorders' (TMDs) classification to include less common but clinically important disorders. The immediate aim was to develop a consensus-based classification system and associated diagnostic criteria that have clinical and research utility for less common TMDs. The long-term aim was to establish a foundation, vis-à-vis this classification system, that will stimulate data collection, validity testing and further criteria refinement. A working group [members of the International RDC/TMD Consortium Network of the International Association for Dental Research (IADR), members of the Orofacial Pain Special Interest Group (SIG) of the International Association for the Study of Pain (IASP), and members from other professional societies] reviewed disorders for inclusion based on clinical significance, the availability of plausible diagnostic criteria and the ability to operationalise and study the criteria. The disorders were derived from the literature when possible and based on expert opinion as necessary. The expanded TMDs taxonomy was presented for feedback at international meetings. Of 56 disorders considered, 37 were included in the expanded taxonomy and were placed into the following four categories: temporomandibular joint disorders, masticatory muscle disorders, headache disorders and disorders affecting associated structures. Those excluded were extremely uncommon, lacking operationalised diagnostic criteria, not clearly related to TMDs, or not sufficiently distinct from disorders already included within the taxonomy. The expanded TMDs taxonomy offers an integrated approach to clinical diagnosis and provides a framework for further research to operationalise and test the proposed taxonomy and diagnostic criteria. © 2014 John Wiley & Sons Ltd.

  19. Long-term implications of observing an expanding cosmological civilization

    Science.gov (United States)

    Olson, S. Jay

    2018-01-01

    Suppose that advanced civilizations, separated by a cosmological distance and time, wish to maximize their access to cosmic resources by rapidly expanding into the universe. How does the presence of one limit the expansionistic ambitions of another, and what sort of boundary forms between their expanding domains? We describe a general scenario for any expansion speed, separation distance and time. We then specialize to a question of particular interest: What are the future prospects for a young and ambitious civilization if they can observe the presence of another at a cosmological distance? We treat cases involving the observation of one or two expanding domains. In the single-observation case, we find that almost any plausible detection will limit one's future cosmic expansion to some extent. Also, practical technological limits to expansion speed (well below the speed of light) play an interesting role. If a domain is visible at the time one embarks on cosmic expansion, higher practical limits to expansion speed are beneficial only up to a certain point. Beyond this point, a higher speed limit means that gains in the ability to expand are more than offset by the first-mover advantage of the observed domain. In the case of two visible domains, it is possible to be `trapped' by them if the practical speed limit is high enough and their angular separation in the sky is large enough, i.e. one's expansion in any direction will terminate at a boundary with the two visible civilizations. Detection at an extreme cosmological distance has surprisingly little mitigating effect on our conclusions.

  20. Environmental CPT Violation in an Expanding Universe in String Theory

    CERN Document Server

    Ellis, John; Sarkar, Sarben

    2013-01-01

    We consider a model of an expanding Universe in string theory that yields `environmental' CPT violation for fermions, in the sense of different dispersion relations for fermions and antifermions. These are induced by a cosmological background with constant torsion provided by the Kalb-Ramond antisymmetric tensor field (axion) of the string gravitational multiplet. This effect induces different densities of neutrinos and antineutrinos while in chemical equilibrium, offering new scenarios for leptogenesis and baryogenesis even in the absence of CP violation.

  1. WORD ORIGIN HELPS EXPAND LEARNERS’ VOCABULARY A VOCABULARY TEACHING APPROACH

    OpenAIRE

    Li Jing

    2012-01-01

    Word origin (motivation) deals with the connection between name and sense, explaining how a word originated. With the knowledge of how words are originated, learners can grasp a word easier and thus expand their vocabulary more quickly. The introduction to word origin (motivation) by teachers can also help the learners gain interest in the process of learning and learn more about the cultural and historical background of the English-speaking countries. This paper tries to clarify this method ...

  2. Korea: an expanding economy trying to gain energy independence

    International Nuclear Information System (INIS)

    Parrott, M.

    1980-01-01

    South Korea expects to have 6426 MW of power installed by 1986, representing 30.7% of its capacity. Following a summary of nuclear activities in South Korea the current situation is discussed. Prospects for energy supply and demand are shown. The difficulties associated with the expanding nuclear programme are mainly on the international front, eg those relating to fuel supply, or to proliferation issue. (UK)

  3. On the creation of particles in some expanding closed universe

    International Nuclear Information System (INIS)

    Nariai, Hidekazu.

    1978-11-01

    The purpose of this letter is to study the pair creation of particles in an expanding universe by analyzing the dynamical behavior of the Feynman propagator. To deal with the pair creation of particles in the universe under consideration, concrete information about the Feynman propagator in the asymptotic region must be obtained. The Feynman propagator is compared with the corresponding one in case of Chitre-Hartle's model-universe. (Kato, T.)

  4. Expanding Science Teacher Preparation: the Role of External Funding

    Science.gov (United States)

    Lindberg, John M.; Vokos, S.; Seeley, L.; Close, E.

    2006-12-01

    The Department of Physics and the School of Education at Seattle Pacific University are in the early stages of expanding the scope and reach of our science teacher preparation. We will describe how we are putting the puzzle together and our results to date. * Supported in part by NSF grant #ESI-0455796, NSF grant # DUE-0630460, NSF grant DUE-0310583, The Boeing Corporation, PhysTec and the SPU Science Initiative.

  5. The bibliometric behaviour of an expanding specialisation of medical research

    Energy Technology Data Exchange (ETDEWEB)

    Thelwall, M.; Levitt, J.

    2016-07-01

    This study investigates macular disease research and cataract research, which are both specialisations of Ophthalmology. Macular disease and cataracts are amongst the three leading causes of blindness in the world. Macular research expanded between 1992 and 2006 in that the proportion of Ophthalmology articles classified as macular increased by over 300% in that period. By contrast, during that same period the proportion of Ophthalmology articles classified as ‘cataract’ decreased by over 20%. This study investigates the bibliometric differences between the rapidly expanding specialisation of ‘macular’ and the slightly contracting specialisation of ‘cataract’. Our rationale for investigating these bibliometric differences is that previous researchers have suggested that articles in expanding specialisations are likely to be more highly cited than articles in relatively static specialisations, and it seems important, when comparing specialisations, to try to ensure that articles in a relatively static specialisation are not penalised. This study first identifies substantial macro-level bibliometric differences between the two specialisations and then gauges the extent to which these differences were associated with the expansion of Macular compared with Cataract. The initial investigation uses coarse-grained delineations of the specialisation, formed from search terms frequently associated with macular (and cataract). It finds that articles in the relatively expanding specialisation were substantially more highly cited and that these differences were associated with the expansion of the specialisation rather than the size of the specialisation (the Matthew effect). A major limitation of this study is that its coarse-grained delineation of specialisations fails to identify substantial numbers of articles in the specialisation. A more fine-grained delineation using PubMed’s Medical Subject Headings (MESH) has been piloted and additional articles

  6. Expanding the Boundaries of Behavioral Integrity in Organizations

    Science.gov (United States)

    2010-07-01

    happened to someone else, subordinates can rationally seek behavioral solutions that punish the managers or the organization they represent (i.e...Thousand Oaks, CA: Sage. Brief, A. P., & Motowidlo, S. J. 1986. Prosocial organizational behaviors . Academy of Management Review, 11(4): 710-725...Dissertation Publication 3. DATES COVERED (From - To) 15-03-2009 to 25-07-2010 4. TITLE AND SUBTITLE Expanding the Boundaries of Behavioral

  7. Debye's length in expanding quark-gluon plasma

    International Nuclear Information System (INIS)

    Bialas, A.

    1988-06-01

    The screening properties of an abelian quark-gluon plasma and boost invariantly expanding in a given direction, are discussed. The expansion results in anisotropic screening. At early stages of the process, the Debye length along the direction of the expansion is reduced by a factor of about 2, relative to static calculations. This may have important consequences for the J/ψ production rate. 12 refs., 2 figs., 1 tab. (author)

  8. The Expanded Public Works Programme: Perspectives of direct beneficiaries

    OpenAIRE

    Mondli S. Hlatshwayo

    2017-01-01

    Scholarship on the Expanded Public Works Programme (EPWP) in South Africa tends to focus on quantitative evaluation to measure the progress made in the implementation of EPWP projects. The number of employment opportunities created by EPWP, demographic profiling, skills acquired by beneficiaries and training opportunities related to the Programme form the basis of typical statistical evaluations of it, but exclude comment by the workers who participate in its projects. Based on primary source...

  9. Efficacy of different bone volume expanders for augmenting lumbar fusions.

    Science.gov (United States)

    Epstein, Nancy E

    2008-01-01

    A wide variety of bone volume expanders are being used in performing posterolateral lumbar noninstrumented and instrumented lumbar fusions. This article presents a review of their efficacy based on fusion rates, complications, and outcomes. Lumbar noninstrumented and instrumented fusions frequently use laminar autografts and different bone graft expanders. This review presents the utility of multiple forms/ratios of DBMs containing allografts. It also discusses the efficacy of artificial bone graft substitutes, including HA and B-TCP. Dynamic x-ray and/or CT examinations were used to document fusion in most series. Outcomes were variously assessed using Odom's criteria or different outcome questionnaires (Oswestry Questionnaire, SF-36, Dallas Pain Questionnaire, and/or Low Back Pain Rating Scale). Performing noninstrumented and instrumented lumbar posterolateral fusions resulted in comparable fusion rates in many series. Similar outcomes were also documented based on Odom's criteria or the multiple patient-based questionnaires. However, in some studies, the addition of spinal instrumentation increased the reoperation rate, operative time, blood loss, and cost. Various forms of DBMs, applied in different ratios to autografts, effectively supplemented spinal fusions in animal models and patient series. beta-Tricalcium phosphate, which is used to augment autograft fusions addressing idiopathic scoliosis or lumbar disease, also proved to be effective. Different types of bone volume expanders, including various forms of allograft-based DBMs, and artificial bone graft substitutes (HA and B-TCP) effectively promote posterolateral lumbar noninstrumented and instrumented fusions when added to autografts.

  10. Enhancing microbial production of biofuels by expanding microbial metabolic pathways.

    Science.gov (United States)

    Yu, Ping; Chen, Xingge; Li, Peng

    2017-09-01

    Fatty acid, isoprenoid, and alcohol pathways have been successfully engineered to produce biofuels. By introducing three genes, atfA, adhE, and pdc, into Escherichia coli to expand fatty acid pathway, up to 1.28 g/L of fatty acid ethyl esters can be achieved. The isoprenoid pathway can be expanded to produce bisabolene with a high titer of 900 mg/L in Saccharomyces cerevisiae. Short- and long-chain alcohols can also be effectively biosynthesized by extending the carbon chain of ketoacids with an engineered "+1" alcohol pathway. Thus, it can be concluded that expanding microbial metabolic pathways has enormous potential for enhancing microbial production of biofuels for future industrial applications. However, some major challenges for microbial production of biofuels should be overcome to compete with traditional fossil fuels: lowering production costs, reducing the time required to construct genetic elements and to increase their predictability and reliability, and creating reusable parts with useful and predictable behavior. To address these challenges, several aspects should be further considered in future: mining and transformation of genetic elements related to metabolic pathways, assembling biofuel elements and coordinating their functions, enhancing the tolerance of host cells to biofuels, and creating modular subpathways that can be easily interconnected. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  11. Covered Balloon-Expanding Stents in Airway Stenosis.

    Science.gov (United States)

    Majid, Adnan; Kheir, Fayez; Chung, Jey; Alape, Daniel; Husta, Bryan; Oh, Scott; Folch, Erik

    2017-04-01

    The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (Pstent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.

  12. Dynamics of a radially expanding liquid sheet: Experiments

    Science.gov (United States)

    Majumdar, Nayanika; Tirumkudulu, Mahesh

    2017-11-01

    A recent theory predicts that sinuous waves generated at the center of a radially expanding liquid sheet grow spatially even in absence of a surrounding gas phase. Unlike flat liquid sheets, the thickness of a radially expanding liquid sheet varies inversely with distance from the center of the sheet. To test the predictions of the theory, experiments were carried out on a horizontal, radially expanding liquid sheet formed by collision of a single jet on a solid impactor. The latter was placed on a speaker-vibrator with controlled amplitude and frequency. The growth of sinuous waves was determined by measuring the wave surface inclination angle using reflected laser light under both atmospheric and sub-atmospheric pressure conditions. It is shown that the measured growth rate matches with the predictions of the theory over a large range of Weber numbers for both pressure conditions suggesting that the thinning of the liquid sheet plays a dominant role in setting the growth rate of sinuous waves with minimal influence of the surrounding gas phase on its dynamics. IIT Bombay.

  13. Why has medicine expanded? The role of consumers.

    Science.gov (United States)

    Zheng, Hui

    2015-07-01

    In the past 50years, the field of medicine has expanded dramatically in many Western societies. Despite substantial improvements in objective health measures, there has not been a commensurate increase in assessments of subjective health. We hypothesize that medical expansion may lower people's subjective health perceptions, leading to an increase in health care utilization, and, in turn, fueling further medical expansion. We use OECD (Organization for Economic Co-operation and Development) Health Data, World Development Indicators, the World Values Survey, and the European Values Study to fit a difference-in-differences model that removes unobserved cross-national heterogeneity and any period trend that is shared across nations. We find that three dimensions of medical expansion at the societal level (medical investment, medical professionalization/specialization, and an expanded pharmaceutical industry) negatively affect individual subjective health. These findings are robust to different model specifications. We conclude by discussing possible explanations for the adverse effect of medical expansion on subjective health, and how this effect may be related to other mechanisms through which medicine expands. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Prospects for expanded utilization of biogas in Germany

    International Nuclear Information System (INIS)

    Poeschl, Martina; Ward, Shane; Owende, Philip

    2010-01-01

    The prospects for expanded utilization of biogas systems in German was analysed, by identifying the operational and policy factors affecting the complete chain of processes from implementation process for biogas plants, through to biogas production and utilization. It was found that the Renewable Energies Act (EEG) and energy tax reliefs provide bases for the support of expanded utilization. Upgrading of biogas to natural gas quality for utilization in the transportation sector was arguably the most promising technology that could support rapid utilization expansion. Sustainable deployment of biogas systems in light of the unstable feedstock prices and availability, and the need for subsidy-free operation in the long term requires; enhancement of feedstock flexibility and quality characteristics to maximise gas yield, and optimisation of the anaerobic digestion process management. Assessment of energy balance and potential environmental impacts of the integrated process chain provides a holistic assessment of sustainability. The results also support the development and foster of policies and framework for development of biogas as environmentally friendly energy resource, among a mix of renewable energy sources, hence, compete favourably with fossil fuels to enhance the prospects for expanded utilization. (author)

  15. Coping with expanding nursing practice, knowledge, and technology.

    Science.gov (United States)

    Gaudinski, M A

    1979-10-01

    Nurses utilize transcultural, transactional, systems, primary, and interdisciplinary approaches to physiological and psychosocial components of patient care. Expanded roles, as well as advances in knowledge and technology have prepared nurses for critical, specialized, primary, aerospace, and independent nursing practice. Exciting as they are, nursing's expanded roles and practices frequently contribute to the burnout and distress phenomena increasingly observed in practicing health care professionals. Causes and symptoms of the burnout distress phenomena are many and varied. Selye, Shubin, Maslach, and others adeptly identified and wrote on the phenomena as it specifically relates to nurses and the many facets of nursing practice. Rather than utilizing crisis intervention coping techniques, preventive strategies and adaptations are suggested. This paper reviews and discusses: 1. Factors associated with burnout-distress phenomena identified in professional literature; 2. Identification of factors associated with expanded roles and practice which contribute to burnout stress; 3. Identification of factors in military and civilian air ambulance and aeromedical evacuation systems which contribute to burnout stress; 4. Recommendations for strategies to prevent and cope with burnout distress factors.

  16. On Dark Energy and Matter of the Expanding Universe

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2009-04-01

    Full Text Available At present the expanding universe is observed to be dominated by the not fully under- stood concepts of dark energy and matter, in a conceived almost flat Euclidian geometry. As one of the possible efforts to understand the global behaviour of the expanding uni- verse, the present paper attempts to explain these concepts in terms of the pressure force and gravity of a spherical photon gas cloud of zero point energy, in a flat geometry. A difficult point of the conventional theory concerns the frequency distribution of the zero point energy oscillations which leads to the unacceptable result of an infinite total en- ergy per unit volume. A modification of this distribution is therefore proposed which results in finite energy density. A corresponding equilibrium state is investigated, as well as small dynamic deviations from it, to form a basis for a model of the expanding universe. Provided that the crucial points of the present approach hold true, the model satisfies the requirements of cosmic linear dimensions, results in an estimated accelera- tion of the expansion being of the order of the observed one, presents a possible solution of the coincidence problem of dark energy and matter, and provides one of the possible explanations of the observed excess of high-energy electrons and positrons in recent balloon and satellite experiments.

  17. Intermingled Bodies. Distributed Agency in an Expanded Appreciation of Making

    Directory of Open Access Journals (Sweden)

    Terence E. Rosenberg

    2013-09-01

    Full Text Available This article offers an expanded view of making and, concomitantly, an understanding that through making we constitute the way we are in the world. The article begins with the idea that making produces a 'surrogate' of the body, which extends the body into the world, reforming the body and the world and their relationship. The ideas the article offers run counter to certain currents of thought that reduce making to a narrow cast anthropocentric crafting. Instead of this reduction, where making is merely understood and fixated as a close inembodied handicraft, the article advances: first, that all that we produce is making – not just that which is crafted by the immediacy of a hand; and, second, and linked to this expanded view of making, that all making workst hrough a distributed agency that includes human and non-human actors and actants in meshworks that extend across space – synchronous - and across time –diachronous. In other words, the body is extended into the world through what is made and this made world acts ineluctably on, and in, making. The paper references the practices of three makers to make the case for the need, bothethical and poetic, to think about making as an expanded term and to consideran intentionality of making that works through distributed agency doubly constituted as material and narrative.

  18. Stability of stagnation via an expanding accretion shock wave

    International Nuclear Information System (INIS)

    Velikovich, A. L.; Giuliani, J. L.; Murakami, M.; Taylor, B. D.; Zalesak, S. T.; Iwamoto, Y.

    2016-01-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  19. Stability of stagnation via an expanding accretion shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Velikovich, A. L.; Giuliani, J. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Taylor, B. D. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC 20375 (United States); Zalesak, S. T. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States); Iwamoto, Y. [Ehime University, Matsuyama, Ehime Pref. 790-8577 (Japan)

    2016-05-15

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  20. Stability of stagnation via an expanding accretion shock wave

    Science.gov (United States)

    Velikovich, A. L.; Murakami, M.; Taylor, B. D.; Giuliani, J. L.; Zalesak, S. T.; Iwamoto, Y.

    2016-05-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  1. Focusing of geodesic congruences in an accelerated expanding Universe

    International Nuclear Information System (INIS)

    Albareti, F.D.; Cembranos, J.A.R.; Cruz-Dombriz, A. de la

    2012-01-01

    We study the accelerated expansion of the Universe through its consequences on a congruence of geodesics. We make use of the Raychaudhuri equation which describes the evolution of the expansion rate for a congruence of timelike or null geodesics. In particular, we focus on the space-time geometry contribution to this equation. By straightforward calculation from the metric of a Robertson-Walker cosmological model, it follows that in an accelerated expanding Universe the space-time contribution to the Raychaudhuri equation is positive for the fundamental congruence, favoring a non-focusing of the congruence of geodesics. However, the accelerated expansion of the present Universe does not imply a tendency of the fundamental congruence to diverge. It is shown that this is in fact the case for certain congruences of timelike geodesics without vorticity. Therefore, the focusing of geodesics remains feasible in an accelerated expanding Universe. Furthermore, a negative contribution to the Raychaudhuri equation from space-time geometry which is usually interpreted as the manifestation of the attractive character of gravity is restored in an accelerated expanding Robertson-Walker space-time at high speeds

  2. Focusing of geodesic congruences in an accelerated expanding Universe

    Energy Technology Data Exchange (ETDEWEB)

    Albareti, F.D.; Cembranos, J.A.R. [Departamento de Física Teórica I, Universidad Complutense de Madrid, Ciudad Universitaria, E-28040 Madrid (Spain); Cruz-Dombriz, A. de la, E-mail: fdalbareti@estumail.ucm.es, E-mail: cembra@fis.ucm.es, E-mail: alvaro.delacruz-dombriz@uct.ac.za [Astrophysics, Cosmology and Gravity Centre (ACGC), University of Cape Town, 7701 Rondebosch, Cape Town (South Africa)

    2012-12-01

    We study the accelerated expansion of the Universe through its consequences on a congruence of geodesics. We make use of the Raychaudhuri equation which describes the evolution of the expansion rate for a congruence of timelike or null geodesics. In particular, we focus on the space-time geometry contribution to this equation. By straightforward calculation from the metric of a Robertson-Walker cosmological model, it follows that in an accelerated expanding Universe the space-time contribution to the Raychaudhuri equation is positive for the fundamental congruence, favoring a non-focusing of the congruence of geodesics. However, the accelerated expansion of the present Universe does not imply a tendency of the fundamental congruence to diverge. It is shown that this is in fact the case for certain congruences of timelike geodesics without vorticity. Therefore, the focusing of geodesics remains feasible in an accelerated expanding Universe. Furthermore, a negative contribution to the Raychaudhuri equation from space-time geometry which is usually interpreted as the manifestation of the attractive character of gravity is restored in an accelerated expanding Robertson-Walker space-time at high speeds.

  3. Porous expandable device for attachment to bone tissue

    Science.gov (United States)

    Rybicki, Edmund F.; Wheeler, Kenneth Ray; Hulbert, Lewis E.; Karagianes, Manuel Tom; Hassler, Craig R.

    1977-01-01

    A device for attaching to substantially solid living bone tissue, comprising a body member having an outer surface shaped to fit approximately into an empty space in the tissue and having pores into which the tissue can grow to strengthen the bond between the device and the tissue, and adjustable means for expanding the body member against the tissue to an extent such as to provide a compressive stress capable of maintaining a snug and stable fit and of enhancing the growth of the tissue into the pores in the body member. The expanding means is adjustable to provide a stress between the tissue and the body member in the range of about 150 to 750 psi, typically 150 to 350 psi. Typically the body member comprises an expandable cylindrical portion having at least one radial slit extending longitudinally from a first end to the vicinity of the opposite (second) end thereof, at least one radial slit extending longitudinally from the second end to the vicinity of the first end thereof, and a tapered cylindrical hole extending coaxially from a wider circular opening in the first end to a narrower circular opening communicating with the second end.

  4. Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    1991-05-15

    To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction.

  5. Wiggler magnetic field assisted third harmonic generation in expanding clusters

    Science.gov (United States)

    Vij, Shivani

    2018-04-01

    A simple theoretical model is constructed to study the wiggler magnetic field assisted third harmonic generation of intense short pulse laser in a cluster in its expanding phase. The ponderomotive force of laser causes density perturbations in cluster electron density which couples with wiggler magnetic field to produce a nonlinear current that generates transverse third harmonic. An intense short pulse laser propagating through a gas embedded with atomic clusters, converts it into hot plasma balls via tunnel ionization. Initially, the electron plasma frequency inside the clusters ω pe > \\sqrt{3}{ω }1 (with ω 1 being the frequency of the laser). As the cluster expands under Coulomb force and hydrodynamic pressure, ω pe decreases to \\sqrt{3}{ω }1. At this time, there is resonant enhancement in the efficiency of the third harmonic generation. The efficiency of third harmonic generation is enhanced due to cluster plasmon resonance and by phase matching due to wiggler magnetic field. The effect of cluster size on the expansion rate is studied to observe that the clusters of different radii would expand differently. The impact of laser intensity and wiggler magnetic field on the efficiency of third harmonic generation is also explored.

  6. Robust size illusion produced by expanding and contracting flow fields.

    Science.gov (United States)

    Dong, Xue; Bai, Jianying; Bao, Min

    2017-04-01

    A new illusion is described. Randomly positioned dots moved radially within an imaginary annular window. The dots' motion periodically changed the direction, leading to an alternating percept of expanding and contracting motion. Strikingly, the apparent size of the enclosed circular region shrank during the dots' expanding phases and dilated during the contracting phases. We quantitatively measured the illusion, and found that the presence of energy at the local kinetic edge could not account for the illusion. Besides, we reproduced the illusion on a natural scene background seen from a first-person point of view that moved forward and backward periodically. Blurring the boundaries of motion areas could not reverse the illusion in all subjects. Taken together, our observed illusion is likely induced by optic flow processing with some components of motion contrast. Expanding or contracting dots may induce the self-motion perception of either approaching or leaving way from the circle. These will make the circle appear smaller or larger since its retinal size remains constant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Expandable metallic stents for tracheobronchial stenoses in esophageal cancer.

    Science.gov (United States)

    Takamori, S; Fujita, H; Hayashi, A; Tayama, K; Mitsuoka, M; Ohtsuka, S; Shirouzu, K

    1996-09-01

    Tracheobronchial stenosis in patients with esophageal cancer can be life threatening. Few reports have discussed use of expandable metallic stents for central airway stenoses in patients with esophageal cancer. Twelve patients with esophageal cancer underwent placement of expandable metallic stents for respiratory distress caused by tracheobronchial stricture. Single or double metallic stents were placed in the stenotic airways under fluoroscopic guidance. Improvement in respiratory symptoms and clinical outcome were assessed. Most stenoses were located in the trachea or the left main bronchus. From one to four expandable metallic stents were placed in each stricture site, with immediate relief of respiratory symptoms in 8 patients. One patient with tracheomalacia in alive 3 years after stent placement and another is alive 6 months after stent insertion. The other 10 patients lived from 10 to 70 days (mean; survival, 35 days) after stent placement. Death was due to progression of disease. Although metallic stents are useful for relieving respiratory distress in patients with advanced esophageal cancer, additional therapies should be considered.

  8. Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

    International Nuclear Information System (INIS)

    Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun

    1991-01-01

    To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction

  9. Polypropylenes foam consisting of thermally expandable microcapsule as blowing agent

    Science.gov (United States)

    Jeoung, Sun Kyung; Hwang, Ye Jin; Lee, Hyun Wook; Kwak, Sung Bok; Han, In-Soo; Ha, Jin Uk

    2016-03-01

    The structure of thermally expandable microcapsule (TEMs) is consisted of a thermoplastic shell which is filled with liquid hydrocarbon at core. The shell of TEMs becomes soft when the temperature is higher than boiling temperature of liquid hydrocarbon. The shell of TEMs is expanded under the high temperature because the inner pressure of TEMs is increased by vaporization of hydrocarbon core. Therefore, the TEMs are applicable for blowing agents and light weight fillers. In this research, we fabricated the polypropylene (PP) foam by using the TEMs and chemical blowing agents and compared to their physical properties. The density of the specimen was decreased when the contents of chemical blowing agents and TEMs were increased. In addition, the mechanical properties (i.e. tensile strength and impact strength) of specimens were deteriorated with increasing amount of chemical blowing agents and TEMs. However, PP foam produced with TEMs showed higher impact strength than the one with the chemical blowing agent. In order to clarify the dependence of impact strength of PP foam as the blowing agent, the morphology difference of the PP foams was investigated. Expanding properties of PP foams produced with TEMs was changed with TEMs content of PP foams. Processing conditions also influenced the mechanical properties of PP foam containing TEMs.

  10. Environmental Assessment Expanded Ponnequin Wind Energy Project Weld County, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    N/A

    1999-03-02

    The U.S.Department of Energy (DOE) has considered a proposal from the State of Colorado, Office of Energy Conservation (OEC), for funding construction of the Expanded Ponnequin Wind Project in Weld County, Colorado. OEC plans to enter into a contracting arrangement with Public Service Company of Colorado (PSCO) for the completion of these activities. PSCo, along with its subcontractors and business partners, are jointly developing the Expanded Ponnequin Wind Project. DOE completed an environmental assessment of the original proposed project in August 1997. Since then, the geographic scope and the design of the project changed, necessitating additional review of the project under the National Environmental Policy Act. The project now calls for the possible construction of up to 48 wind turbines on State and private lands. PSCo and its partners have initiated construction of the project on private land in Weld County, Colorado. A substation, access road and some wind turbines have been installed. However, to date, DOE has not provided any funding for these activities. DOE, through its Commercialization Ventures Program, has solicited applications for financial assistance from state energy offices, in a teaming arrangement with private-sector organizations, for projects that will accelerate the commercialization of emerging renewable energy technologies. The Commercialization Ventures Program was established by the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989 (P.L. 101-218) as amended by the Energy Policy Act of 1992 (P.L. 102-486). The Program seeks to assist entry into the marketplace of newly emerging renewable energy technologies, or of innovative applications of existing technologies. In short, an emerging renewable energy technology is one which has already proven viable but which has had little or no operational experience. The Program is managed by the Department of Energy, Office of Energy Efficiency and Renewable Energy. The

  11. Effect of expansion temperature of expandable graphite on microstructure evolution of expanded graphite during high-energy ball-milling

    International Nuclear Information System (INIS)

    Yue Xueqing; Li Liang; Zhang Ruijun; Zhang Fucheng

    2009-01-01

    Two expanded graphites (EG), marked as EG-1 and EG-2, were prepared by rapid heating of expandable graphite to 600 and 1000 deg. C, respectively, and ball milled in a high-energy mill (planetary-type) under air atmosphere. The microstructure evolution of the ball-milled samples was characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). XRD analysis shows that the evolution degree of the average crystallite thickness along the c-axis (L c ) of EG-2 is lower than that of EG-1 during the milling process. From the HRTEM images of the samples after 100 h ball-milling, slightly curved graphene planes can be frequently observed both in the two EGs, however, EG-1 and EG-2 exhibit sharply curved graphene planes and smoothly curved graphene planes with high bending angles, respectively.

  12. Innovative isothermal oil-free co-rotating scroll compressor–expander for energy storage with first expander tests

    International Nuclear Information System (INIS)

    Iglesias, A.; Favrat, D.

    2014-01-01

    Highlights: • Doing a new concept of small scale compressed air energy storage. • Presenting a new working process of scroll machinery. • Updating a thermodynamic model of scroll compressor that take into account water injection. • Updating a mathematical model of volumetric loses that take into account sealing effect of liquid water. • Encouraging results to investigate more deeply this new concept. - Abstract: The development of an efficient isothermal turbine and compressor is essential for the realization of a small-scale compressed air energy storage (CAES). This article presents the theoretical development of an oil-free co-rotating scroll air compressor and turbine working with water injection to make the operations of expansion and compression as isothermal as possible. First experimental results in expander mode are shown. The theoretical performance is predicted with the help of a mathematical model using the equations of energy and mass conservation and the equation of state. This model takes into account the effects of water injection and volumetric losses. The experimental prototype is an oil-free scroll air compressor with the distinctive feature of having two mobile involutes working in synchronized co-rotation one relative to another. The prime-mover is an electric motor driving the two scrolls with two synchronizing belts. Water injection in the housing intends to provide a quasi-isothermal compression. The same device is used as an isothermal expander by supplying high-pressure air with water when it rotates backwards in expander mode, the electric motor acting then as a generator. Expected improvements to a standard scroll compressor and expander are a better volumetric efficiency and a greater power density due to a higher rotational speed of the scrolls, thanks to their symmetrical masses. The isothermal processes increase also the overall performance

  13. Cryo-electron Microscopy Structures of Expanded Poliovirus with VHHs Sample the Conformational Repertoire of the Expanded State.

    Science.gov (United States)

    Strauss, Mike; Schotte, Lise; Karunatilaka, Krishanthi S; Filman, David J; Hogle, James M

    2017-02-01

    By using cryo-electron microscopy, expanded 80S-like poliovirus virions (poliovirions) were visualized in complexes with four 80S-specific camelid VHHs (Nanobodies). In all four complexes, the VHHs bind to a site on the top surface of the capsid protein VP3, which is hidden in the native virus. Interestingly, although the four VHHs bind to the same site, the structures of the expanded virus differ in detail in each complex, suggesting that each of the Nanobodies has sampled a range of low-energy structures available to the expanded virion. By stabilizing unique structures of expanded virions, VHH binding permitted a more detailed view of the virus structure than was previously possible, leading to a better understanding of the expansion process that is a critical step in infection. It is now clear which polypeptide chains become disordered and which become rearranged. The higher resolution of these structures also revealed well-ordered conformations for the EF loop of VP2, the GH loop of VP3, and the N-terminal extensions of VP1 and VP2, which, in retrospect, were present in lower-resolution structures but not recognized. These structural observations help to explain preexisting mutational data and provide insights into several other stages of the poliovirus life cycle, including the mechanism of receptor-triggered virus expansion. When poliovirus infects a cell, it undergoes a change in its structure in order to pass RNA through its protein coat, but this altered state is short-lived and thus poorly understood. The structures of poliovirus bound to single-domain antibodies presented here capture the altered virus in what appear to be intermediate states. A careful analysis of these structures lets us better understand the molecular mechanism of infection and how these changes in the virus lead to productive-infection events. Copyright © 2017 American Society for Microbiology.

  14. Expanded algal cultivation can reverse key planetary boundary transgressions

    Directory of Open Access Journals (Sweden)

    Dean Calahan

    2018-02-01

    Full Text Available Humanity is degrading multiple ecosystem services, potentially irreversibly. Two of the most important human impacts are excess agricultural nutrient loading in our fresh and estuarine waters and excess carbon dioxide in our oceans and atmosphere. Large-scale global intervention is required to slow, halt, and eventually reverse these stresses. Cultivating attached polyculture algae within controlled open-field photobioreactors is a practical technique for exploiting the ubiquity and high primary productivity of algae to capture and recycle the pollutants driving humanity into unsafe regimes of biogeochemical cycling, ocean acidification, and global warming. Expanded globally and appropriately distributed, algal cultivation is capable of removing excess nutrients from global environments, while additionally sequestering appreciable excess carbon. While obviously a major capital and operational investment, such a project is comparable in magnitude to the construction and maintenance of the global road transportation network. Beyond direct amelioration of critical threats, expanded algal cultivation would produce a major new commodity flow of biomass, potentially useful either as a valuable organic commodity itself, or used to reduce the scale of the problem by improving soils, slowing or reversing the loss of arable land. A 100 year project to expand algal cultivation to completely recycle excess global agricultural N and P would, when fully operational, require gross global expenses no greater than $2.3 × 1012 yr−1, (3.0% of the 2016 global domestic product and less than 1.9 × 107 ha (4.7 × 107 ac, 0.38% of the land area used globally to grow food. The biomass generated embodies renewable energy equivalent to 2.8% of global primary energy production.

  15. Ambipolar ion acceleration in an expanding magnetic nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Longmier, Benjamin W; Carter, Mark D; Cassady, Leonard D; Chancery, William J; Diaz, Franklin R Chang; Glover, Tim W; Ilin, Andrew V; McCaskill, Greg E; Olsen, Chris S; Squire, Jared P [Ad Astra Rocket Company, 141 W. Bay Area Blvd, Webster, TX (United States); Bering, Edgar A III [Department of Physics and Department of Electrical and Computer Engineering, University of Houston, 617 Science and Research Building 1, Houston, TX (United States); Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Dr., Madison, WI (United States)

    2011-02-15

    The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR (registered)) VX-200i device was used to characterize an axial plasma potential profile within an expanding magnetic nozzle region of the laboratory based device. The ion acceleration mechanism is identified as an ambipolar electric field produced by an electron pressure gradient, resulting in a local axial ion speed of Mach 4 downstream of the magnetic nozzle. A 20 eV argon ion kinetic energy was measured in the helicon source, which had a peak magnetic field strength of 0.17 T. The helicon plasma source was operated with 25 mg s{sup -1} argon propellant and 30 kW of RF power. The maximum measured values of plasma density and electron temperature within the exhaust plume were 1 x 10{sup 20} m{sup -3} and 9 eV, respectively. The measured plasma density is nearly an order of magnitude larger than previously reported steady-state helicon plasma sources. The exhaust plume also exhibits a 95% to 100% ionization fraction. The size scale and spatial location of the plasma potential structure in the expanding magnetic nozzle region appear to follow the size scale and spatial location of the expanding magnetic field. The thickness of the potential structure was found to be 10{sup 4} to 10{sup 5} {lambda}{sub De} depending on the local electron temperature in the magnetic nozzle, many orders of magnitude larger than typical laboratory double layer structures. The background plasma density and neutral argon pressure were 10{sup 15} m{sup -3} and 2 x 10{sup -5} Torr, respectively, in a 150 m{sup 3} vacuum chamber during operation of the helicon plasma source. The agreement between the measured plasma potential and plasma potential that was calculated from an ambipolar ion acceleration analysis over the bulk of the axial distance where the potential drop was located is a strong confirmation of the ambipolar acceleration process.

  16. Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2002-04-01

    To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

  17. Methods for expanding the capacity of spent fuel storage facilities

    International Nuclear Information System (INIS)

    1990-06-01

    At the beginning of 1989 more than 55,000 metric tonnes of heavy metal (MTHM) of spent Light Water Reactor (LWR) and Heavy Water Reactor (HWR) fuel had been discharged worldwide from nuclear power plants. Only a small fraction of this fuel has been reprocessed. The majority of the spent fuel assemblies are currently held at-reactor (AR) or away-from-reactor (AFR) in storage awaiting either chemical processing or final disposal depending on the fuel concept chosen by individual countries. Studies made by NEA and IAEA have projected that annual spent fuel arising will reach about 10,000 t HM in the year 2000 and cumulative arising will be more than 200,000 t HM. Taking into account the large quantity of spent fuel discharged from NPP and that the first demonstrations of the direct disposal of spent fuel or HLW are expected only after the year 2020, long-term storage will be the primary option for management of spent fuel until well into the next century. There are several options to expand storage capacity: (1) to construct new away-from-reactor storage facilities, (2) to transport spent fuel from a full at-reactor pool to another site for storage in a pool that has sufficient space to accommodate it, (3) to expand the capacity of existing AR pools by using compact racks, double-tierce, rod consolidation and by increasing the dimensions of existing pools. The purpose of the meeting was: to exchange new information on the international level on the subject connected with the expansion of storage capacities for spent fuel; to elaborate the state-of-the-art of this problem; to define the most important areas for future activity; on the basis of the above information to give recommendations to potential users for selection and application of the most suitable methods for expanding spent fuel facilities taking into account the relevant country's conditions. Refs, figs and tabs

  18. Emissions reductions from expanding state-level renewable portfolio standards.

    Science.gov (United States)

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-05

    In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power.

  19. Expanding Access to Pro-Poor Energy Services in Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Eleri, Ewah Otu; Ugwu, Okechukwu; Onuvae, Precious

    2012-10-15

    Nigeria experiences a remarkable paradox -- the abundance of energy resources and widespread energy poverty. Only about 40% of the population has access to the country’s grid electricity. About 72% of the population depends on traditional fuelwood for cooking. Despite this, government financing of energy services that benefits majority of Nigeria’s population has been grossly inadequate. Private sector investments and donor support have not fared better. This paper examines the current level of energy poverty in Nigeria. It analyses the level of government, private sector and donor funding for energy services that benefit the poor. It further reviews international best practices in expanding access for pro poor energy services. The paper finds a significant decline in political interest for expanding electricity services to rural areas. Even though ambitious policy reforms have commenced, agreed programmes are not implemented effectively. Not only are investments in rural electrification in decline, there is no history of annual budgeting for cooking energy programmes. The paper recommends a number of action points for expanding access to energy services that benefit the poor. These include the development and launching of a new national rural electrification strategy; establishment of a national cooking energy programme; and the development of clear policy incentives to support private sector investment in energy services for the poor. It calls on the Nigerian Central Bank of Nigeria to set aside 10% of the existing power intervention fund for pro poor energy financing; and the Nigerian Electricity Regulatory Commission to establish a clear framework for the utilization of the Consumer Assistance Fund. Other recommendations include the use of a proportion of the Ecological Fund to finance cooking energy; establishment of a donor’s platform on pro poor energy; and the mobilization of civil society in providing community-level energy services.

  20. Self-expandable nitinol stent placement in homocysteinemic porcine aorta

    Directory of Open Access Journals (Sweden)

    Luís Henrique Gil França

    2008-01-01

    Full Text Available PURPOSE: To compare aortic intimal thickening of normal and hyperhomocysteinemic pigs (induced with a methionine-rich diet following placement of a self-expanding nitinol stent. METHODS: Eighteen Macau pigs were used. They were older than eight weeks in age and had an average weight of 30 kg. Pigs were randomly divided into two groups. The first, Group C (control, was fed a regular diet, and the second group, Group M, was fed a methionine-rich diet for 30 days to induce hyperhomocysteinemia. The self-expandable nitinol stents were 25mm in length and 8 mm in diameter after expansion. Blood samples were collected to measure total cholesterol, triglycerides, HDL and homocysteine concentrations. All animals were subjected to angiography. Thirty days after the procedure, the animals were sacrificed, and the abdominal aorta was removed for histological and digital morphometry analysis. RESULTS: Under microscopic evaluation, the intima was significantly thicker in Group C than in Group M. When groups were compared by digital morphometric analysis, intimal thickening of the vessel wall was higher in Group C than in Group M. There was no significant change in total cholesterol, triglycerides or HDL concentrations in either group. In group C the levels of plasma homocysteine ranged from 14,40 to 16,73µmol/l; in Group M, plasma homocysteine levels ranged from 17.47 to 59.80 µmol/l after 30 days of a methionine-rich diet. CONCLUSION: Compared to normal pigs, less intimal hyperplasia was observed in the abdominal aortas of hyperhomocysteinemic pigs thirty days after the insertion of a self-expandable nitinol stent.

  1. Particle creation and particle number in an expanding universe

    International Nuclear Information System (INIS)

    Parker, Leonard

    2012-01-01

    I describe the logical basis of the method that I developed in 1962 and 1963 to define a quantum operator corresponding to the observable particle number of a quantized free scalar field in a spatially-flat isotropically expanding (and/or contracting) universe. This work also showed for the first time that particles were created from the vacuum by the curved spacetime of an expanding spatially-flat Friedmann–Lemaître–Robertson–Walker (FLRW) universe. The same process is responsible for creating the nearly scale-invariant spectrum of quantized perturbations of the inflaton scalar field during the inflationary stage of the expansion of the universe. I explain how the method that I used to obtain the observable particle number operator involved adiabatic invariance of the particle number (hence, the name adiabatic regularization) and the quantum theory of measurement of particle number in an expanding universe. I also show how I was led in a surprising way, to the discovery in 1964 that there would be no particle creation by these spatially-flat FLRW universes for free fields of any integer or half-integer spin satisfying field equations that are invariant under conformal transformations of the metric. The methods I used to define adiabatic regularization for particle number were based on generally-covariant concepts like adiabatic invariance and measurement that were fundamental and determined results that were unique to each given adiabatic order. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (paper)

  2. Treatment of esophagopleural fistulas using covered retrievable expandable metallic stents.

    Science.gov (United States)

    Kim, Tae-Hyung; Shin, Ji Hoon; Kim, Kyung Rae; Park, Jung-Hoon; Kim, Jin Hyoung; Song, Ho-Young

    2014-04-01

    To evaluate the clinical efficacy of placement of covered retrievable expandable metallic stents for esophagopleural fistulas (EPFs). During the period 1997-2013, nine patients with EPF were treated using covered retrievable expandable metallic stents. The underlying causes of EPF were esophageal carcinoma (n = 6), lung cancer (n = 2), and postoperative empyema for Boerhaave syndrome (n = 1). Technical success was achieved in eight patients (88.9%). In one patient, incomplete EPF closure was due to incomplete stent expansion. Clinical success, defined as complete EPF closure within 7 days, was achieved in five patients (55.6%). Overall fistula persistence (n = 1) or reopening (n = 4) occurred in five patients (55.6%) 0-15 days after stent placement. The causes of reopening were due to the gap between the stent and the esophagus (n = 3) or stent migration (n = 1). For fistula persistence or reopening, additional interventional management, such as gastrostomy, stent removal, or stent reinsertion, was performed. Stent migration occurred as a complication in one patient with EPF from a benign cause secondary to postoperative empyema. In the eight patients who died during the follow-up period, the mean and median survival times were 78.8 days and 46 days, respectively. Placement of a covered expandable metallic esophageal stent for the palliative treatment of EPF is technically feasible, although the rate of clinical success was poor secondary to fistula persistence or reopening. Fistula reopening was caused by the gap between the stent and the esophagus or by stent migration, and additional interventional treatment was useful to ensure enteral nutritional support. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

  3. Hydrodynamization and transient modes of expanding plasma in kinetic theory

    CERN Document Server

    Heller, Michal P.; Spalinski, Michal

    2016-01-01

    We study the transition to hydrodynamics in a weakly-coupled model of quark-gluon plasma given by kinetic theory in the relaxation time approximation. Our studies uncover qualitative similarities to the results on hydrodynamization in strongly coupled gauge theories. In particular, we demonstrate that the gradient expansion in this model has vanishing radius of convergence. The asymptotic character of the hydrodynamic gradient expansion is crucial for the recently discovered applicability of hydrodynamics at large gradients. Furthermore, the analysis of the resurgent properties of the series provides, quite remarkably, indication for the existence of a novel transient, damped oscillatory mode of expanding plasmas in kinetic theory.

  4. Avoiding Intellectual Stagnation: The Starship as an Expander of Minds

    Science.gov (United States)

    Crawford, Ian A.

    2014-06-01

    Interstellar exploration will advance human knowledge and culture in multiple ways. Scientifically, it will advance our understanding of the interstellar medium, stellar astrophysics, planetary science and astrobiology. In addition, significant societal and cultural benefits will result from a programme of interstellar exploration and colonisation. Most important will be the cultural stimuli resulting from expanding the horizons of human experience, and increased opportunities for the spread and diversification of life and culture through the Galaxy. Ultimately, a programme of interstellar exploration may be the only way for human (and post-human) societies to avoid the intellectual stagnation predicted for the `end of history'.

  5. Validation of the Chinese expanded Euthanasia Attitude Scale.

    Science.gov (United States)

    Chong, Alice Ming-Lin; Fok, Shiu-Yeu

    2013-01-01

    This article reports the validation of the Chinese version of an expanded 31-item Euthanasia Attitude Scale. A 4-stage validation process included a pilot survey of 119 college students and a randomized household survey with 618 adults in Hong Kong. Confirmatory factor analysis confirmed a 4-factor structure of the scale, which can therefore be used to examine attitudes toward general, active, passive, and non-voluntary euthanasia. The scale considers the role effect in decision-making about euthanasia requests and facilitates cross-cultural comparison of attitudes toward euthanasia. The new Chinese scale is more robust than its Western predecessors conceptually and measurement-wise.

  6. The expanding shell test: Numerical simulation of the experiment

    International Nuclear Information System (INIS)

    Buy, Francois; Llorca, Fabrice

    2002-01-01

    The behavior of materials at very high strain rates is a broad field of investigation. One of the major problem is to impose a well known velocity and stress loading. The expanding shell, because of its ability to impose a sudden loading with no ulterior stress, has been retained to analyze the mechanical behavior of several metals through the free flight of a deforming structure. We perform several simulations on various metals in order to evaluate the strain rates and velocity in the sample. A second step consists in interpreting experimental data obtained on these metals

  7. Plane and hemispherical potential structures in magnetically expanding plasmas

    International Nuclear Information System (INIS)

    Takahashi, Kazunori; Igarashi, Yuichi; Fujiwara, Tamiya

    2010-01-01

    Two-dimensional potential structures are measured for different gas pressure in expanding argon plasma using permanent magnets, where the magnetic field is about 100 G in the source and several gauss in the diffusion chamber. The plane potential drop is observed near the source exit for 0.35 mTorr, while the potential structure becomes hemispherical when increasing up to 1 mTorr; the hemispherical structure results in the radial divergence of the ion beam. It is found that the trajectories of the accelerated ions and the electrons overcoming the potential drop are dominated by the potential structure and magnetic-field lines, respectively.

  8. Expanding gerontology enrollments: successful results of an innovative outreach program.

    Science.gov (United States)

    Reynolds, Sandra L; Haley, William E; Hyer, Kathryn

    2007-01-01

    As state budget allocations for higher education decrease, "specialty" programs such as gerontology must continually demonstrate their productivity. State and private universities increasingly rely on student credit hours (SCH) or tuition generated, which is making it difficult for many gerontology programs to expand. The School of Aging Studies at the University of South Florida has achieved a 236% increase in annual SCH productivity over the past 5 years by methods including qualifying courses for university liberal arts requirements, and designing and cross-listing interdisciplinary courses. This increased productivity has supported program expansion and led to beneficial outreach to students from diverse majors.

  9. Efficient decoding of random errors for quantum expander codes

    OpenAIRE

    Fawzi , Omar; Grospellier , Antoine; Leverrier , Anthony

    2017-01-01

    We show that quantum expander codes, a constant-rate family of quantum LDPC codes, with the quasi-linear time decoding algorithm of Leverrier, Tillich and Z\\'emor can correct a constant fraction of random errors with very high probability. This is the first construction of a constant-rate quantum LDPC code with an efficient decoding algorithm that can correct a linear number of random errors with a negligible failure probability. Finding codes with these properties is also motivated by Gottes...

  10. Decomposition kinetics of expanded austenite with high nitrogen contents

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2006-01-01

    This paper addresses the decomposition kinetics of synthesized homogeneous expanded austenite formed by gaseous nitriding of stainless steel AISI 304L and AISI 316L with nitrogen contents up to 38 at.% nitrogen. Isochronal annealing experiments were carried out in both inert (N2) and reducing (H2......) atmospheres. Differential thermal analysis (DTA) and thermogravimetry were applied for identification of the decomposition reactions and X-ray diffraction analysis was applied for phase analysis. CrN precipitated upon annealing; the activation energies are 187 kJ/mol and 128 kJ/mol for AISI 316L and AISI 304L...

  11. Proton fire hose instabilities in the expanding solar wind

    Czech Academy of Sciences Publication Activity Database

    Hellinger, Petr

    2017-01-01

    Roč. 83, č. 1 (2017), č. článku 705830105. ISSN 0022-3778 Institutional support: RVO:68378289 Keywords : astrophysicals plasmas * plasma expansion * plasma simulation Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 1.160, year: 2016 https://www.cambridge.org/ core /journals/journal-of-plasma-physics/article/proton-fire-hose-instabilities-in-the-expanding-solar-wind/6BA70378B25728533588A1A68073AC2F

  12. Beyond the numbers: expanding the boundaries of neuropsychology.

    Science.gov (United States)

    Perry, William

    2009-02-01

    Beyond the Numbers: Expanding the Boundaries of Neuropsychology was Dr Perry's 2007 presidential address in the annual conference of the National Academy of Neuropsychology. In his address he discussed the achievements of the science of neuropsychology and highlighted some areas that exemplified the expansion of the boundaries of neuropsychology. These areas are: (i) the study of neuropsychological functioning in new or non-traditional populations, particularly seemingly healthy people and people with non-brain diseases; (ii) the interface of cognition and genetics; (iii) the use of the process approach as a means of understanding brain functioning; and (iv) a translational application to the science of neuropsychology.

  13. Plasmatron with expanding channel of outlet electrode and its applications

    International Nuclear Information System (INIS)

    Chinnov, V.F.; Isakajev, E.Kh.; Ivanov, P.P.; Sinkevich, O.A.; Tyuftyaev, A.S.

    2000-01-01

    A serious industrial application is found for the plasmatron with expanding channel of outlet electrode - hardening and nitriding surface treatment of railway wheels. Several plasma installations are under operation at the engine houses of Moscow Railways. More than 12 000 wheel sets have been treated up to now. Results are evident: wheel life doubles due to plasma treatment. The plasmatron developed essentially in an empiric way is now under heavy investigation both theoretically and experimentally. High precision measurements of nitrogen emission spectra are expected to be used directly for accurate calculation of radiation heat loss term in a quasi-one dimensional flow code. (Authors)

  14. Can the United States Expand Apprenticeship? Lessons from Experience

    OpenAIRE

    Lerman, Robert I.

    2012-01-01

    Can expanded apprenticeship reduce the concerns about the U.S. workforce? The U.S. labor market faces a rise in unemployment rates, sharp declines in the employed share of U.S. adults, extremely high youth unemployment, high wage inequality, and low or stagnant wage growth for workers below the BA degree. Currently, the primary solution advanced by policymakers – helping more people go to college – is both expensive and of limited effectiveness. Unfortunately, the U.S. policy debate is rarely...

  15. Bose-Einstein correlation of particles produced by expanding sources

    International Nuclear Information System (INIS)

    Hama, Y.; Padula, S.S.

    1988-01-01

    Bose-Einstein correlation is discussed for particles produced by rapidly expanding sources, when kinematical effects hinder a direct relation between the observed correlations and the source dimensions. Some of these effects are illustrated by considering Landau's hydrodynamical model wherein each space-time point of the fluid with temperature T = T/sub c/≅m/sub π/ is taken as an independent and chaotic emitting center with a Planck spectral distribution. In particular, this model reproduces surprisingly well the observed π-π and K-K correlations at the CERN ISR

  16. WORD ORIGIN HELPS EXPAND LEARNERS’ VOCABULARY A VOCABULARY TEACHING APPROACH

    Directory of Open Access Journals (Sweden)

    Li Jing

    2012-12-01

    Full Text Available Word origin (motivation deals with the connection between name and sense, explaining how a word originated. With the knowledge of how words are originated, learners can grasp a word easier and thus expand their vocabulary more quickly. The introduction to word origin (motivation by teachers can also help the learners gain interest in the process of learning and learn more about the cultural and historical background of the English-speaking countries. This paper tries to clarify this method of teaching from four aspects: onomatopoeia, word formation, cultural and historical background and cognitive linguistics.

  17. Self expandable polytetrafluoroethylene stent for carotid blowout syndrome.

    Science.gov (United States)

    Tatar, E C; Yildirim, U M; Dündar, Y; Ozdek, A; Işik, E; Korkmaz, H

    2012-01-01

    Carotid blowout syndrome (CBS) is an emergency complication in patients undergoing treatment for head and neck cancers. The classical management of CBS is the ligation of the common carotid artery, because suturing is not be possible due to infection and necrosis of the field. In this case report, we present a patient with CBS, in whom we applied a self-expandable polytetrafluoroethylene (PTFE) stent and observed no morbidity. Endovascular stent is a life-saving technique with minimum morbidity that preserves blood flow to the brain. We believe that this method is preferable to ligation of the artery in CBS.

  18. Using Aesthetic Response, a Poetic Inquiry to Expand Knowing

    DEFF Research Database (Denmark)

    Gerge, Anna; Warja, Margareta; Pedersen, Inge Nygaard

    2017-01-01

    affective neuroscience aimed at deepening the understanding of embodied felt sense. The Rx6 approach is based in aesthetics, a pragmatic pre-understanding inspired from an interpretive and a constructivist tradition, and it is a heuristic endeavour where art is applied towards the creation of meaning......Using Aesthetic Response, a Poetic Inquiry to Expand Knowing Abstract: The Rx6-Method A simple step-wise research procedure of arts-based research (ABR) called the Rx6 method is presented. This ABR method is grounded in expressive arts therapy, heuristic inquiry, attachment theory and contemporary...

  19. Beyond the Numbers: Expanding the Boundaries of Neuropsychology†

    Science.gov (United States)

    Perry, William

    2009-01-01

    Beyond the Numbers: Expanding the Boundaries of Neuropsychology was Dr Perry's 2007 presidential address in the annual conference of the National Academy of Neuropsychology. In his address he discussed the achievements of the science of neuropsychology and highlighted some areas that exemplified the expansion of the boundaries of neuropsychology. These areas are: (i) the study of neuropsychological functioning in new or non-traditional populations, particularly seemingly healthy people and people with non-brain diseases; (ii) the interface of cognition and genetics; (iii) the use of the process approach as a means of understanding brain functioning; and (iv) a translational application to the science of neuropsychology. PMID:19395354

  20. Complication after self expandable metallic stent for esophageal cancer

    International Nuclear Information System (INIS)

    Nagahama, Takeshi; Maruyama, Michio; Kato, Kiyomi; Shinoura, Hiroshi; Hasegawa, Kumi; Takashima, Itaru; Ebuchi, Masakazu

    2003-01-01

    Major complications after placement of esophageal stent and airway stent were reviewed and evaluated. Four patients, including two patients with perforations and two patients with fistula formation, developed major complications after placement of a self expandable metallic stent. Two patients underwent additional radiation to improve stricture after stent placement. In one patient, stent placement was selected to improve esophageal stricture that occurred after radical radiation therapy. In one patient, migration of stent into the lesion caused a perforation. It can be concluded that additional radiation after stent placement increases the risk of complication. Stent migration also can lead to the risk of perforation. (author)

  1. The development of structure in the expanding universe

    Science.gov (United States)

    Silk, J.; White, S. D.

    1978-01-01

    A model for clustering in an expanding universe is developed based on an application of the coagulation equation to the collision and aggregation of bound condensations. While the growth rate of clustering is determined by the rate at which density fluctuations reach the nonlinear regime and therefore depends on the initial fluctuation spectrum, the mass spectrum rapidly approaches a self-similar limiting form. This form is determined by the tidal processes which lead to the merging of condensations, and is not dependent on initial conditions.

  2. Three Dimensional Numerical Code for the Expanding Flat Universe

    Directory of Open Access Journals (Sweden)

    Kyoung W. Min

    1987-12-01

    Full Text Available The current distribution of galaxies may contain clues to the condition of the universe when the galaxies condensed and to the nature of the subsequent expansion of the universe. The development of this large scale structure can be studied by employing N-body computer simulations. The present paper describes the code developed for this purpose. The computer code calculates the motion of collisionless matter action under the force of gravity in an expanding flat universe. The test run of the code shows the error less than 0.5% in 100 iterations.

  3. Comparative study of organovermiculites using natural and expanded vermiculite

    International Nuclear Information System (INIS)

    Andrea, L.S.; Hudson, A.B.; Francisco, K.S.; Romualdo, R.M.; Gelmires, A.N.; Lisiane, N.L.S.

    2012-01-01

    Organovermiculites were obtained using vermiculite clay in its natural state and expanded in order to use these new materials in the adsorption of organic contaminants from water. Analysis by X-ray diffraction, infrared spectroscopy (IR), thermogravimetry (TG) and differential thermal analysis (DTA) were performed to obtain confirmation of these organovermiculites. Foster swelling and sorption tests were used to test the compatibility between the treated clay and organic solvents. The organophilization process has provided an increase in basal distance of vermiculite and it was observed an expressive increase in distance between the clay layers. The organovermiculite showed adsorption capacity by organic solvents tested, the best results were observed for diesel oil. (author)

  4. Evaluated Rayleigh integrals for pulsed planar expanding ring sources

    International Nuclear Information System (INIS)

    Warshaw, S.I.

    1985-01-01

    Time-domain analytic and semianalytic pressure fields acoustically radiated from expanding pulsed ring sources imbedded in a planar rigid baffle have been calculated. The source functions are radially symmetric delta-function distributions whose amplitude and argument have simple functional dependencies on radius and time. Certain cases yield closed analytic results, while others result in elliptic integrals, which are evaluated to high accuracy by Gauss-Chebyshev and modified Gauss-Legendre quadrature. These results are of value for calibrating computer simulations and convolution procedures, and estimating fields from more complex planar radiators. 3 refs., 4 figs

  5. Global gas processing will strengthen to meet expanding markets

    International Nuclear Information System (INIS)

    Haun, R.R.; Otto, K.W.; Whitley, S.C.; Gist, R.L.

    1996-01-01

    The worldwide LPG industry continues to expand faster than the petroleum industry -- 4%/year for LPG vs. 2%/year for petroleum in 1995 and less than 1%/year in the early 1990s. This rapid expansion of LPG markets is occurring in virtually every region of the world, including such developing countries as China. The Far East is the focus of much of the LPG industry's attention, but many opportunities exist in other regions such as the Indian subcontinent, Southeast Asia, and Latin America. The investment climate is improving in all phases of downstream LPG marketing, including terminaling, storage, and wholesale and retail distribution. The world LPG supply/demand balance has been relatively tight since the Gulf War and should remain so. Base demand (the portion of demand that is not highly price-sensitive) is expanding more rapidly than supplies. As a result, the proportion of total LPG supplies available for price-sensitive petrochemical feedstock markets is declining, at least in the short term. The paper discusses importers, price patterns, world LPG demand, world LPG supply, US NGL supply, US gas processing, ethane and propane supply, butane, isobutane, and natural gasoline supply, and US NGL demand

  6. A Study of Flexible Composites for Expandable Space Structures

    Science.gov (United States)

    Scotti, Stephen J.

    2016-01-01

    Payload volume for launch vehicles is a critical constraint that impacts spacecraft design. Deployment mechanisms, such as those used for solar arrays and antennas, are approaches that have successfully accommodated this constraint, however, providing pressurized volumes that can be packaged compactly at launch and expanded in space is still a challenge. One approach that has been under development for many years is to utilize softgoods - woven fabric for straps, cloth, and with appropriate coatings, bladders - to provide this expandable pressure vessel capability. The mechanics of woven structure is complicated by a response that is nonlinear and often nonrepeatable due to the discrete nature of the woven fiber architecture. This complexity reduces engineering confidence to reliably design and certify these structures, which increases costs due to increased requirements for system testing. The present study explores flexible composite materials systems as an alternative to the heritage softgoods approach. Materials were obtained from vendors who utilize flexible composites for non-aerospace products to determine some initial physical and mechanical properties of the materials. Uniaxial mechanical testing was performed to obtain the stress-strain response of the flexible composites and the failure behavior. A failure criterion was developed from the data, and a space habitat application was used to provide an estimate of the relative performance of flexible composites compared to the heritage softgoods approach. Initial results are promising with a 25% mass savings estimated for the flexible composite solution.

  7. Looking for trouble? Diagnostics expanding disease and producing patients.

    Science.gov (United States)

    Hofmann, Bjørn

    2018-05-23

    Novel tests give great opportunities for earlier and more precise diagnostics. At the same time, new tests expand disease, produce patients, and cause unnecessary harm in overdiagnosis and overtreatment. How can we evaluate diagnostics to obtain the benefits and avoid harm? One way is to pay close attention to the diagnostic process and its core concepts. Doing so reveals 3 errors that expand disease and increase overdiagnosis. The first error is to decouple diagnostics from harm, eg, by diagnosing insignificant conditions. The second error is to bypass proper validation of the relationship between test indicator and disease, eg, by introducing biomarkers for Alzheimer's disease before the tests are properly validated. The third error is to couple the name of disease to insignificant or indecisive indicators, eg, by lending the cancer name to preconditions, such as ductal carcinoma in situ. We need to avoid these errors to promote beneficial testing, bar harmful diagnostics, and evade unwarranted expansion of disease. Accordingly, we must stop identifying and testing for conditions that are only remotely associated with harm. We need more stringent verification of tests, and we must avoid naming indicators and indicative conditions after diseases. If not, we will end like ancient tragic heroes, succumbing because of our very best abilities. © 2018 John Wiley & Sons, Ltd.

  8. LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES

    Energy Technology Data Exchange (ETDEWEB)

    Luna-Cardozo, M. [Instituto de Astronomia y Fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Verth, G. [School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom); Erdelyi, R., E-mail: mluna@iafe.uba.ar, E-mail: robertus@sheffield.ac.uk, E-mail: gary.verth@northumbria.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2012-04-01

    Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

  9. Expanding the concept of sustainable seafood using Life Cycle Assessment

    DEFF Research Database (Denmark)

    Ziegler, Friederike; Hornborg, Sara; Green, Bridget S

    2016-01-01

    Fisheries management and sustainability assessment of fisheries more generally have recently expanded their scope from single-species stock assessment to ecosystem-based approaches, aiming to incorporate economic, social and local environmental impacts, while still excluding global-scale environm......Fisheries management and sustainability assessment of fisheries more generally have recently expanded their scope from single-species stock assessment to ecosystem-based approaches, aiming to incorporate economic, social and local environmental impacts, while still excluding global......-offs, LCA can be a useful decision support tool and avoids problem shifting from one concern (or activity) to another. The integrated, product-based and quantitative perspective brought by LCA could complement existing tools. One example is to follow up fuel use of fishing, as the production and combustion...... performance could likewise facilitate the transition to low-impact fisheries. Taking these steps in an open dialogue between fishers, managers, industry, NGOs and consumers would enable more targeted progress towards sustainable fisheries...

  10. Expanding OPEC production capacity: some legal and environmental aspects

    International Nuclear Information System (INIS)

    Al-Sahlawi, M.A.

    1992-01-01

    There is general consensus that the global demand for oil will increase in the medium-to-long term. It is predicted that much of this additional demand will be for OPEC oil. Therefore, it will become necessary to expand OPEC production capacity to meet this perceived increase. In recent years, many OPEC countries have launched far-reaching and, in some cases, radical plans to expand their production capacity. However, given the various investment and political constraints faced by the 13 OPEC Members, each country differs markedly in its ability to boost production capacity sufficiently to meet self-imposed targets. In this paper, we examine the importance to the oil market of recent oil supply trends and possible future attempts to build OPEC production capacity, focussing in particular on the legal and environmental issues involved. A review is provided of the legal mechanisms currently evolving in OPEC Countries to encourage investment in their oil industries. In addition, we outline the impact of the environmental movement of OPEC's expansion programmes. (author)

  11. CT examination of expanding processes in cerebellopontine angle

    International Nuclear Information System (INIS)

    Bauer, J.; Kvicala, V.; Faltynova, E.

    1988-01-01

    A contribution is evaluated of computerized tomography to the diagnosis of expanding processes localized in the pontocerebellar corner of posterior cranial fossa, particularly neurinomas of n. statoacousticus. In cases of expanding processes in this region, especially in minor expansions, CT examination must be performed in a specially selected way, always after the intravenous administration of a contrast agent. The diagnosis of small neurinomas of n. statoacousticus, localized mostly in intracanalicullar portion, in the external auditory duct proved to be particularly difficult. In these cases, computerized pneumomeatography proved to be of a particular value; CT examination of the internal auditory duct and its neighbourhood was performed after previous filling of this region with air which, in most cases, well differentiated expansions into adjacent structures. It is confirmed in agreement with reports in the literature, that in cases of serious clinical suspicion and negative or controversial finding by classical CT examination, computerized pneumomeatography is the method of choice in the diagnosis of small isodense neurinomas of nervus statoacousticus. (author). 10 refs

  12. Pitfalls in soft tissue sarcoma imaging: chronic expanding hematomas.

    Science.gov (United States)

    Jahed, Kiarash; Khazai, Behnaz; Umpierrez, Monica; Subhawong, Ty K; Singer, Adam D

    2018-01-01

    Solid or nodular enhancement is typical of soft tissue sarcomas although high grade soft tissue sarcomas and those with internal hemorrhage often appear heterogeneous with areas of nonenhancement and solid or nodular enhancement. These MRI findings often prompt an orthopedic oncology referral, a biopsy or surgery. However, not all masses with these imaging findings are malignant. We report the multimodality imaging findings of two surgically proven chronic expanding hematomas (CEH) with imaging features that mimicked sarcomas. A third case of nonenhancing CEH of the lower extremity is also presented as a comparison. It is important that in the correct clinical scenario with typical imaging findings, the differential diagnosis of a chronic expanding hematoma be included in the workup of these patients. An image-guided biopsy of nodular tissue within such masses that proves to be negative for malignancy should not necessarily be considered discordant. A correct diagnosis may prevent a morbid unnecessary surgery and may indicate the need for a conservative noninvasive follow-up with imaging.

  13. Proposal for Certifying Expandable Planetary Surface Habitation Structures

    Science.gov (United States)

    Dorsey, John T.

    2011-01-01

    A factor-of-safety (FS) of 4.0 is currently used to design habitation structures made from structural soft goods. This approach is inconsistent with using a FS of 2.0 for metallic and polymeric composite pressure vessels as well as soft good structures such as space suits and parachutes. This inconsistency arises by using the FS to improperly account for the unknown effects of a variety of environmental and loading uncertainties. Using a 4.0 FS not only results in additional structural mass, it also makes it difficult to gain insight into the limitations of the material and/or product form and thus, it becomes difficult to make improvements. In order to bring consistency to the design and certification of expandable habitat structures, the approach used by the Federal Aviation Administration (FAA) to certify polymeric composite aircraft structures is used as a model and point of departure. A draft certification plan for Expandable Habitat Structures is developed in this paper and offered as an option for placing habitats made from soft goods on an equal footing with other structural implementations.

  14. SRS K-area material storage. Expanding capabilities

    International Nuclear Information System (INIS)

    Koenig, R.

    2013-01-01

    In support of the Department of Energy’s continued plans to de-inventory and reduce the footprint of Cold War era weapons’ material production sites, the K-Area Material Storage (KAMS) facility, located in the K-Area Complex (KAC) at the Savannah River Site reservation, has expanded since its startup authorization in 2000 to accommodate DOE’s material consolidation mission. During the facility’s growth and expansion, KAMS will have expanded its authorization capability of material types and storage containers to allow up to 8200 total shipping containers once the current expansion effort completes in 2014. Recognizing the need to safely and cost effectively manage other surplus material across the DOE Complex, KAC is constantly evaluating the storage of different material types within K area. When modifying storage areas in KAC, the Documented Safety Analysis (DSA) must undergo extensive calculations and reviews; however, without an extensive and proven security posture the possibility for expansion would not be possible. The KAC maintains the strictest adherence to safety and security requirements for all the SNM it handles. Disciplined Conduct of Operations and Conduct of Projects are demonstrated throughout this historical overview highlighting various improvements in capability, capacity, demonstrated cost effectiveness and utilization of the KAC as the DOE Center of Excellence for safe and secure storage of surplus SNM.

  15. Ecological and evolutionary processes at expanding range margins.

    Science.gov (United States)

    Thomas, C D; Bodsworth, E J; Wilson, R J; Simmons, A D; Davies, Z G; Musche, M; Conradt, L

    2001-05-31

    Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change.

  16. An experimental study on expandable endovascular metallic stents in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Kim, Hak Nam [Chonbuk National University College of Medicine, Chonju (Korea, Republic of)

    1990-12-15

    We constructed an expandable endovascular metallic stent in the same way as Giamturco did. Experiments were made to test the ability of these stents to be used in the vessels. A total of 20 stents were passed through a 8.5 French teflon sheath into the normal abdominal aorta. IVC, and iliac artery of four adult dogs for 4 weeks to 12 weeks; 8 stents (10 mm in diameter fully expanded and 20 mm in length) in the abnormal aorta, 7 stents (12 mm/20 mm) in the IVC, and 5 stents (8 mm/20 mm) in the iliac artery. All but two stents showed no migration, and one complete occlusion occurred in right iliac artery of a dog. Histologically, stents wires were covered by neo-intimal proliferation. The side branches of the main vessels remained patent, even stent wires across their orifices. These metallic stents may be used as an endovascular graft material in the nonsurgical treatment of several forms of vascular disease.

  17. Malignant Gastroduodenal Obstruction: Treatment with Self-Expanding Uncovered Wallstent

    International Nuclear Information System (INIS)

    Gutzeit, Andreas; Binkert, Christoph A.; Schoch, Eric; Sautter, Thomas; Jost, Res; Zollikofer, Christoph L.

    2009-01-01

    Purpose: To retrospectively evaluate the clinical effectiveness of a self-expanding uncovered Wallstent in patients with malignant gastroduodenal obstruction. Materials and Methods: Under combined endoscopic and fluoroscopic guidance, 29 patients with a malignant gastroduodenal stenosis were treated with a self-expanding uncovered metallic Wallstent. A dysphagia score was assessed before and after the intervention to measure the success of this palliative therapy. The dysphagia score ranged between grade 0 to grade 4: grade 0 = able to tolerate solid food, grade 1 = able to tolerate soft food, grade 2 = able to tolerate thick liquids, grade 3 = able to tolerate water or clear fluids, and grade 4 = unable to tolerate anything perorally. Stent patency and patients survival rates were calculated. Results: The insertion of the gastroduodenal stent was technically successful in 28 patients (96.5%). After stenting, 25 patients (86.2%) showed clinical improvement by at least one score point. During follow-up, 22 (78.5%) of 28 patients showed no stent occlusion until death and did not have to undergo any further intervention. In six patients (20.6%), all of whom were treated with secondary stent insertions, occlusion with tumor ingrowth and/or overgrowth was observed after the intervention. The median period of primary stent patency in our study was 240 days. Conclusion: Placement of an uncovered Wallstent is clinically effective in patients with malignant gastroduodenal obstruction. Stent placement is associated with high technical success, good palliation effect, and high durability of stent function.

  18. Expanding the role for psychology in addressing environmental challenges.

    Science.gov (United States)

    Clayton, Susan; Devine-Wright, Patrick; Swim, Janet; Bonnes, Mirilia; Steg, Linda; Whitmarsh, Lorraine; Carrico, Amanda

    2016-04-01

    Environmental challenges, though daunting, present an important area for psychologists to apply their knowledge. Psychological theories, research methods, and interventions are essential for examining the questions about human impacts, tendencies, and capacities that are integral to constructing effective responses to these challenges. Although a great deal of relevant research has been done, there is scope for psychologists to be more extensively involved. Following a brief review of existing research, we outline some important new directions. We also highlight 2 key divergences, arguing that psychological research needs to expand beyond a traditional, theory-based and decontextualized approach to environmental issues to incorporate a contextualized or "place-based" approach and a willingness to collaborate in interdisciplinary research teams that focus on specific environmental problems. Suggestions for promoting such interdisciplinary collaborations are reviewed. We encourage psychologists to expand their engagement with important environmental issues through multiple research approaches in order to further their understanding of human behavior, contributions to human well-being, and relevance to other disciplines and to society. (c) 2016 APA, all rights reserved).

  19. Evolution of gravitational orbits in the expanding universe

    International Nuclear Information System (INIS)

    Sereno, Mauro; Jetzer, Philippe

    2007-01-01

    The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale size R. In a universe with significant dark matter, a gravitational system expands or contracts according to the amount and equation of state of the dark energy. At present time, the Solar System, according to the ΛCDM scenario emerging from observational cosmology, should be expanding if we consider only the effect of the cosmological background. Its fate is determined by the equation of state of the dark energy alone. The mean motion and periastron precession of a planet are directly sensitive to Re/R, whereas variations with time in the semimajor axis and eccentricity are related to its time variation. Actual bounds on the cosmological deceleration parameters q 0 from accurate astrometric data of perihelion precession and changes in the third Kepler's law in the Solar System fall short of 10 orders of magnitude with respect to estimates from observational cosmology. Future radio-ranging measurements of outer planets could improve actual bounds by 5 orders of magnitude

  20. The expanding regulatory universe of p53 in gastrointestinal cancer.

    Science.gov (United States)

    Fesler, Andrew; Zhang, Ning; Ju, Jingfang

    2016-01-01

    Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer.

  1. Expand your English a guide to improving your academic vocabulary

    CERN Document Server

    Hart, Steve

    2018-01-01

    Writing academic prose in English is especially difficult for non-native speakers, largely because the standard vocabulary used in this genre can be quite different from colloquial English. Expand Your English: A Guide to Improving Your Academic Vocabulary is a unique and invaluable guide that will enable the reader to overcome this hurdle. It will become the favourite go-to reference book for both beginners and for intermediate learners struggling with the complexities of English-language academic writing. Steve Hart covers 1,000 vocabulary items that are essential for good academic writing. The first section describes 200 key terms in detail, grouping them into logical sets of 10. Through careful repetition, the reader will find it easy to retain, retrieve, and reuse these essential phrases. The second section explains a further 800 terms, grouping them according to function, meaning, and the areas of an essay where they are likely to be used. The expansive scope of Expand Your English gives non-native spea...

  2. Asymmetric creation of matter and antimatter in the expanding universe

    International Nuclear Information System (INIS)

    Papastamatiou, N.J.; Parker, L.

    1979-01-01

    We consider a simple model in which the matter-antimatter asymmetry of the universe is brought about by an effective two-particle interaction that violates baryon-number conservation as well as CP invariance. The particle fields participating in the interaction are quantized, and their time development in an isotropically expanding universe is found to all orders in the coupling constant. Pair production by the asymmetric interaction, as well as symmetric production by the gravitational field of the expanding universe, appear simultaneously in the solution. Taking an initial state in which no particles participating in the asymmetric interaction are present, we find the created baryon-number density. We consider in more detail the case when the matter-antimatter asymmetry is produced during a stage when the radius of the universe is small with respect to its present value. We make numerical estimates of the created matter-antimatter asymmetry, and put limits on possible values of the parameters of this model

  3. Expanded Mixed Multiscale Finite Element Methods and Their Applications for Flows in Porous Media

    KAUST Repository

    Jiang, L.; Copeland, D.; Moulton, J. D.

    2012-01-01

    We develop a family of expanded mixed multiscale finite element methods (MsFEMs) and their hybridizations for second-order elliptic equations. This formulation expands the standard mixed multiscale finite element formulation in the sense that four

  4. A programmatic challenge - accelerating, expanding, and innovating physical protection

    International Nuclear Information System (INIS)

    Caravelli, J.

    2002-01-01

    Full text: In the wake of the September 11th terrorists attacks, the Office of international material protection and cooperation is responding to the international community's call to strengthen a global response to the serious challenge of securing nuclear material with the aim of preventing nuclear terrorism. Recent events underline the urgency to proactively address the threat posed by insufficiently secured nuclear material. The sobering reality is that, at present, the threat is disproportional to international efforts to mitigate and stop the proliferation of nuclear materials. The potential consequences of failing to address deficiencies in security systems, or for that matter aiming at anything below 'comprehensive' nuclear material security' is a horrifying reminder of the incredible challenge that we are facing. Against this backdrop, our Office has undertaken a comprehensive program review and is making all possible efforts to expand, accelerate and innovate our physical protection approach. The presentation that I propose to deliver will provide an overview of our new thinking regarding the vulnerability of nuclear/radioactive material post 9-11, touch on some of the obstacles that we are experiencing, and outline the steps that we are aggressively pursuing with the aim of achieving real threat reduction. My presentation will begin with a look at the success and knowledge gained from the bilateral material protection, control and accounting (MPC and A) cooperation between the United States and the Russian Federation and use this as a platform from which to launch a wider discussion on international efforts to strengthen practices for protecting nuclear material. I will examine lessons learned from our cooperation in relation to their applicability to today's security challenges and will outline how we are expanding on our traditional mission to address emerging threats. I will discuss programmatic efforts to bolster traditional, first line of defense

  5. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-06-01

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  6. 49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Polymeric beads, expandable and Plastic molding... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non-bulk shipments of Polymeric beads (or granules), expandable, evolving flammable vapor and Plastic...

  7. Battery energy storage market feasibility study - Expanded report

    International Nuclear Information System (INIS)

    Kraft, S.; Akhil, A.

    1997-09-01

    Under the sponsorship of the US Department of Energy's Office of Utility Technologies, the Energy Storage Systems Analysis and Development Department at Sandia National Laboratories (SNL) contracted Frost and Sullivan to conduct a market feasibility study of energy storage systems. The study was designed specifically to quantify the battery energy storage market for utility applications. This study was based on the SNL Opportunities Analysis performed earlier. Many of the groups surveyed, which included electricity providers, battery energy storage vendors, regulators, consultants, and technology advocates, viewed battery storage as an important technology to enable increased use of renewable energy and as a means to solve power quality and asset utilization issues. There are two versions of the document available, an expanded version (approximately 200 pages, SAND97-1275/2) and a short version (approximately 25 pages, SAND97-1275/1)

  8. Expanding perspectives on cognition in humans, animals, and machines.

    Science.gov (United States)

    Gomez-Marin, Alex; Mainen, Zachary F

    2016-04-01

    Over the past decade neuroscience has been attacking the problem of cognition with increasing vigor. Yet, what exactly is cognition, beyond a general signifier of anything seemingly complex the brain does? Here, we briefly review attempts to define, describe, explain, build, enhance and experience cognition. We highlight perspectives including psychology, molecular biology, computation, dynamical systems, machine learning, behavior and phenomenology. This survey of the landscape reveals not a clear target for explanation but a pluralistic and evolving scene with diverse opportunities for grounding future research. We argue that rather than getting to the bottom of it, over the next century, by deconstructing and redefining cognition, neuroscience will and should expand rather than merely reduce our concept of the mind. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Novel biliary self-expanding metal stents: indications and applications.

    Science.gov (United States)

    Blero, Daniel; Huberty, Vincent; Devière, Jacques

    2015-03-01

    Endoscopic insertion of a self-expanding metal stent (SEMS) through a malignant common bile duct stricture is the first line of palliation for malignant jaundice. Patency of these stents remains a major concern. SEMS dysfunction can result from tumor ingrowth, overgrowth and/or clogging. Initial SEMS modifications involved covering the central part of the stent in order to reduce ingrowth and ultimately increase patency. Fully covered stents became available shortly after reports of their use in human patients. The potential removability and radial strength of SEMS have led to evaluation of their use in new indications including benign biliary strictures, post sphincterotomy bleeding and perforation. Other aspects of development include the addition of features such as anti-reflux valves, drug elution and spontaneous biodegradability. These aspects and their clinical implications are reviewed and discussed.

  10. Expanding the Possibilities of AIS Data with Heuristics

    Directory of Open Access Journals (Sweden)

    Bjørnar Brende Smestad

    2017-06-01

    Full Text Available Automatic Identification System (AIS is primarily used as a tracking system for ships, but with the launch of satellites to collect these data, new and previously untested possibilities are emerging. This paper presents the development of heuristics for establishing the specific ship type using information retrieved from AIS data alone. These heuristics expand the possibilities of AIS data, as the specific ship type is vital for several transportation research cases, such as emission analyses of ship traffic and studies on slow steaming. The presented method for developing heuristics can be used for a wider range of vessels. These heuristics may form the basis of large-scale studies on ship traffic using AIS data when it is not feasible or desirable to use commercial ship data registers.

  11. Gemini Observatory Takes its Local Communities on an Expanding Journey

    Science.gov (United States)

    Harvey, Janice; Michaud, Peter

    2012-08-01

    Currently in its 7th year (2011) Hawaii's annual Journey through the Universe (JttU) program is a flagship Gemini Observatory public education/outreach initiative involving a broad cross-section of the local Hawai'i Island astronomical community, the public, educators, businesses, local government officials, and thousands of local students. This paper describes the program, its history, planning, implementation, as well as the program's objectives and philosophy. The success of this program is documented here, as measured by continuous and expanding engagement of educators, the community, and the public, along with formal evaluation feedback and selected informal verbal testimony. The program's success also serves as justification for the planned adaptation of a version of the program in Chile in 2011 (adapted for Chilean educational and cultural differences). Finally, lessons learned are shared which have refined the program for Gemini's host communities but can also apply to any institution wishing to initiate a similar program.

  12. The use of expanded clay dust in paint manufacturing

    Science.gov (United States)

    Sverguzova, S. V.; Sapronova, Zh A.; Starostina, Yu L.; Belovodskiy, E. A.

    2018-01-01

    Production increase of useful products is accompanied by the formation and the accumulation of the vast amounts of industrial wastes, the bulk of which is not involved in the recycling processes. An example of such wastes is dust bag filters of ceramsite production. At the large enterprises, the volume of its formation can reach 7-8 tons of dust per day, which is 10-15% of feedstock mass. The studies on the use of ceramsite production dust as filler pigment in the composition of organic mixed primer of red-brown color are carried out in this work. For comparison, red iron oxide pigment (Pg FGM) was used. The results showed that, primer with the use of expanded clay dust is characterized by the short drying time and meets all regulatory requirements.

  13. Expanding options in radiation oncology: neutron beam therapy

    International Nuclear Information System (INIS)

    Cohen, L.

    1982-01-01

    Twelve years experience with neutron beam therapy in Britain, the USA, Europe and Japan shows that local control is achievable in late-stage epidermoid cancer somewhat more frequently than with conventional radiotherapy. Tumours reputed to be radioresistant (salivary gland, bladder, rectosigmoid, melanoma, bone and soft-tissue sarcomas) have proved to be particularly responsive to neutrons. Pilot studies in brain and pancreatic tumours suggest promising new approaches to management of cancer in these sites. The availability of neutron therapy in the clinical environment opens new prospects for irradiation of 'radioresistant' tumours, permits more conservative cancer surgery, expands the use of elective chemotherapy and provides a wider range of options for cancer patients. (author)

  14. A Few Expanding Integrable Models, Hamiltonian Structures and Constrained Flows

    International Nuclear Information System (INIS)

    Zhang Yufeng

    2011-01-01

    Two kinds of higher-dimensional Lie algebras and their loop algebras are introduced, for which a few expanding integrable models including the coupling integrable couplings of the Broer-Kaup (BK) hierarchy and the dispersive long wave (DLW) hierarchy as well as the TB hierarchy are obtained. From the reductions of the coupling integrable couplings, the corresponding coupled integrable couplings of the BK equation, the DLW equation, and the TB equation are obtained, respectively. Especially, the coupling integrable coupling of the TB equation reduces to a few integrable couplings of the well-known mKdV equation. The Hamiltonian structures of the coupling integrable couplings of the three kinds of soliton hierarchies are worked out, respectively, by employing the variational identity. Finally, we decompose the BK hierarchy of evolution equations into x-constrained flows and t n -constrained flows whose adjoint representations and the Lax pairs are given. (general)

  15. Nonequilibrium quark production in the expanding QCD plasma

    Science.gov (United States)

    Tanji, Naoto; Berges, Jürgen

    2018-02-01

    We perform real-time lattice simulations of nonequilibrium quark production in the longitudinally expanding QCD plasma. Starting from a highly occupied gluonic state with vacuum quark sector, we extract the time evolution of quark and gluon number densities per unit transverse area and rapidity. The total quark number shows after an initial rapid increase an almost linear growth with time. Remarkably, this growth rate appears to be consistent with a simple kinetic theory estimate involving only two-to-two scattering processes in small-angle approximation. This extends previous findings about the role of two-to-two scatterings for purely gluonic dynamics in accordance with the early stages of the bottom-up thermalization scenario.

  16. Kinetic theory of a longitudinally expanding system of scalar particles

    International Nuclear Information System (INIS)

    Epelbaum, Thomas; Gelis, François; Jeon, Sangyong; Moore, Guy; Wu, Bin

    2015-01-01

    A simple kinematical argument suggests that the classical approximation may be inadequate to describe the evolution of a system with an anisotropic particle distribution. In order to verify this quantitatively, we study the Boltzmann equation for a longitudinally expanding system of scalar particles interacting with a ϕ 4 coupling, that mimics the kinematics of a heavy ion collision at very high energy. We consider only elastic 2→2 scatterings, and we allow the formation of a Bose-Einstein condensate in overpopulated situations by solving the coupled equations for the particle distribution and the particle density in the zero mode. For generic CGC-like initial conditions with a large occupation number, the solutions of the full Boltzmann equation cease to display the classical attractor behavior sooner than expected; for moderate coupling, the solutions appear never to follow a classical attractor solution.

  17. Linear response formula for piecewise expanding unimodal maps

    International Nuclear Information System (INIS)

    Baladi, Viviane; Smania, Daniel

    2008-01-01

    The average R(t) = ∫φdμ t of a smooth function ψ with respect to the SRB measure μ t of a smooth one-parameter family f t of piecewise expanding interval maps is not always Lipschitz (Baladi 2007 Commun. Math. Phys. 275 839–59, Mazzolena 2007 Master's Thesis Rome 2, Tor Vergata). We prove that if f t is tangent to the topological class of f, and if ∂ t f t | t=0 = X circle f, then R(t) is differentiable at zero, and R'(0) coincides with the resummation proposed (Baladi 2007) of the (a priori divergent) series given by Ruelle's conjecture. In fact, we show that t map μ t is differentiable within Radon measures. Linear response is violated if and only if f t is transversal to the topological class of f

  18. The Yaglom law in the expanding solar wind

    International Nuclear Information System (INIS)

    Gogoberidze, G.; Perri, S.; Carbone, V.

    2013-01-01

    We study the Yaglom law, which relates the mixed third-order structure function to the average dissipation rate of turbulence, in a uniformly expanding solar wind by using the two-scale expansion model of magnetohydrodynamic (MHD) turbulence. We show that due to the expansion of the solar wind, two new terms appear in the Yaglom law. The first term is related to the decay of the turbulent energy by nonlinear interactions, whereas the second term is related to the non-zero cross-correlation of the Elsässer fields. Using magnetic field and plasma data from WIND and Helios 2 spacecrafts, we show that at lower frequencies in the inertial range of MHD turbulence the new terms become comparable to Yaglom's third-order mixed moment, and therefore they cannot be neglected in the evaluation of the energy cascade rate in the solar wind.

  19. Gas-Generator Augmented Expander Cycle Rocket Engine

    Science.gov (United States)

    Greene, William D. (Inventor)

    2011-01-01

    An augmented expander cycle rocket engine includes first and second turbopumps for respectively pumping fuel and oxidizer. A gas-generator receives a first portion of fuel output from the first turbopump and a first portion of oxidizer output from the second turbopump to ignite and discharge heated gas. A heat exchanger close-coupled to the gas-generator receives in a first conduit the discharged heated gas, and transfers heat to an adjacent second conduit carrying fuel exiting the cooling passages of a primary combustion chamber. Heat is transferred to the fuel passing through the cooling passages. The heated fuel enters the second conduit of the heat exchanger to absorb more heat from the first conduit, and then flows to drive a turbine of one or both of the turbopumps. The arrangement prevents the turbopumps exposure to combusted gas that could freeze in the turbomachinery and cause catastrophic failure upon attempted engine restart.

  20. Selection of nanoparticles using CO.sub.2-expanded liquids

    Science.gov (United States)

    Roberts, Christopher B; McLeod, Marshall Chandler; Anand, Madhu

    2013-02-19

    A method for size selection of nanostructures comprising utilizing a gas-expanded liquids (GEL) and controlled pressure to precipitate desired size populations of nanostructures, e.g., monodisperse. The GEL can comprise CO.sub.2 antisolvent and an organic solvent. The method can be carried out in an apparatus comprising a first open vessel configured to allow movement of a liquid/particle solution to specific desired locations within the vessel, a second pressure vessel, a location controller for controlling location of the particles and solution within the first vessel, a inlet for addition of antisolvent to the first vessel, and a device for measuring the amount of antisolvent added. Also disclosed is a method for forming nanoparticle thin films comprising utilizing a GEL containing a substrate, pressurizing the solution to precipitate and deposit nanoparticles onto the substrate, removing the solvent thereby leaving a thin nanoparticle film, removing the solvent and antisolvent, and drying the film.

  1. Statistical effect of interactions on particle creation in expanding universe

    International Nuclear Information System (INIS)

    Kodama, Hideo

    1982-01-01

    The statistical effect of interactions which drives many-particle systems toward equilibrium is expected to change the qualitative and quantitative features of particle creation in expanding universe. To investigate this problem a simplified model called the finite-time reduction model is formulated and applied to the scalar particle creation in the radiation dominant Friedmann universe. The number density of created particles and the entropy production due to particle creation are estimated. The result for the number density is compared with that in the conventional free field theory. It is shown that the statistical effect increases the particle creation and lengthens the active creation period. As for the entropy production it is shown that it is negligible for scalar particles in the Friedmann universe. (author)

  2. Expanding P450 catalytic reaction space through evolution and engineering

    Science.gov (United States)

    McIntosh, John A.; Farwell, Christopher C.; Arnold, Frances H.

    2014-01-01

    Advances in protein and metabolic engineering have led to wider use of enzymes to synthesize important molecules. However, many desirable transformations are not catalyzed by any known enzyme, driving interest in understanding how new enzymes can be created. The cytochrome P450 enzyme family, whose members participate in xenobiotic metabolism and natural products biosynthesis, catalyzes an impressive range of difficult chemical reactions that continues to grow as new enzymes are characterized. Recent work has revealed that P450-derived enzymes can also catalyze useful reactions previously accessible only to synthetic chemistry. The evolution and engineering of these enzymes provides an excellent case study for how to genetically encode new chemistry and expand biology’s reaction space. PMID:24658056

  3. Medical humanities and philosophy: is the universe expanding or contracting?

    Science.gov (United States)

    Stempsey, William E

    2007-12-01

    The question of whether the universe is expanding or contracting serves as a model for current questions facing the medical humanities. The medical humanities might aptly be described as a metamedical multiverse encompassing many separate universes of discourse, the most prominent of which is probably bioethics. Bioethics, however, is increasingly developing into a new interdisciplinary discipline, and threatens to engulf the other medical humanities, robbing them of their own distinctive contributions to metamedicine. The philosophy of medicine considered as a distinct field of study has suffered as a result. Indeed, consensus on whether the philosophy of medicine even constitutes a legitimate field of study is lacking. This paper presents an argument for the importance of a broad conception of the philosophy of medicine and the central role it should play in organizing and interpreting the various fields of study that make up the metamedical multiverse.

  4. Expanded cardiac rehabilitation in socially vulnerable patients with myocardial infarction

    DEFF Research Database (Denmark)

    Hald, Kathrine; Nielsen, Kirsten Melgaard; Nielsen, Claus Vinther

    2018-01-01

    ). The patients were defined as socially vulnerable or non-socially vulnerable according to their educational level and their social network. A complete follow-up was achieved. INTERVENTION: A socially differentiated CR intervention. The intervention consisted of standard CR and additionally a longer phase II......OBJECTIVE: Cardiac rehabilitation (CR) has been shown to reduce cardiovascular risk. A research project performed at a university hospital in Denmark offered an expanded CR intervention to socially vulnerable patients. One-year follow-up showed significant improvements concerning medicine...... compliance, lipid profile, blood pressure and body mass index when compared with socially vulnerable patients receiving standard CR. The aim of the study was to perform a long-term follow-up on the socially differentiated CR intervention and examine the impact of the intervention on all-cause mortality...

  5. Metagenome of a Versatile Chemolithoautotroph from Expanding Oceanic Dead Zones

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, David A.; Zaikova, Elena; Howes, Charles L.; Song, Young; Wright, Jody; Tringe, Susannah G.; Tortell, Philippe D.; Hallam, Steven J.

    2009-07-15

    Oxygen minimum zones (OMZs), also known as oceanic"dead zones", are widespread oceanographic features currently expanding due to global warming and coastal eutrophication. Although inhospitable to metazoan life, OMZs support a thriving but cryptic microbiota whose combined metabolic activity is intimately connected to nutrient and trace gas cycling within the global ocean. Here we report time-resolved metagenomic analyses of a ubiquitous and abundant but uncultivated OMZ microbe (SUP05) closely related to chemoautotrophic gill symbionts of deep-sea clams and mussels. The SUP05 metagenome harbors a versatile repertoire of genes mediating autotrophic carbon assimilation, sulfur-oxidation and nitrate respiration responsive to a wide range of water column redox states. Thus, SUP05 plays integral roles in shaping nutrient and energy flow within oxygen-deficient oceanic waters via carbon sequestration, sulfide detoxification and biological nitrogen loss with important implications for marine productivity and atmospheric greenhouse control.

  6. Surprises in the suddenly-expanded infinite well

    International Nuclear Information System (INIS)

    Aslangul, Claude

    2008-01-01

    I study the time evolution of a particle prepared in the ground state of an infinite well after the latter is suddenly expanded. It turns out that the probability density |Ψ(x, t)| 2 shows up quite a surprising behaviour: for definite times, plateaux appear for which |Ψ(x, t)| 2 is constant on finite intervals for x. Elements of theoretical explanation are given by analysing the singular component of the second derivative ∂ xx Ψ(x, t). Analytical closed expressions are obtained for some specific times, which easily allow us to show that, at these times, the density organizes itself into regular patterns provided the size of the box is large enough; more, above some critical size depending on the specific time, the density patterns are independent of the expansion parameter. It is seen how the density at these times simply results from a construction game with definite rules acting on the pieces of the initial density

  7. The expanding universe of Sherlockian fandom and archival collections

    Directory of Open Access Journals (Sweden)

    Timothy Jerome Johnson

    2017-03-01

    Full Text Available Since 1887, in sometimes cosmic fashion, nearly every medium and format has been used in sharing the original 60 Sherlock Holmes adventures along with their pastiche and parodying offspring. Such creative energy is evidence of a literary big bang, and an expanding universe of creative possibilities, many of them now born digital or residing on digital platforms. We trace older and newer Sherlockian enthusiasms; their points of entry; the creative manifestations of these fandoms over time and through various media; and the emerging challenges and opportunities presented to library and archival professionals by the explosive growth of creative works, especially those produced during the last decade. Curatorial actions involving acquisition, preservation, description, and user discovery of these materials are considered alongside the relationship building necessary between curator and fan in acquiring evolving, dynamic new Sherlockian expressions and insights.

  8. Bremsstrahlung radiation of a plasma expanding into vacuum

    International Nuclear Information System (INIS)

    Grigor'ev, V.G.; Silakov, V.P.; Fetisov, V.S.

    1978-01-01

    Bremsstrahlung of a flat layer of a dense hot homogeneous plasma expanding to vacuum is considered. The spread of plasma is assumed to be adiabatic, and the plasma density and temperature are considered as known functions of coordinates and time in the radiation transport equation. Formulae for radiation intensity have been obtained in cases when the plasma layer covered by the rarefaction wave are optically thin and optically thick. The dependences of radiation intensity on the parameter α characterizing the optical thickness of the plasma layer and the spectrum of radiation of the spreading layer are presented graphically. It is shown that spread has an essential effect on the heat transfer and the spectral composition of the bremsstrahlung of a dense high-temperature plasma

  9. Artificially Expanded Genetic Information Systems for New Aptamer Technologies

    Directory of Open Access Journals (Sweden)

    Elisa Biondi

    2018-05-01

    Full Text Available Directed evolution was first applied to diverse libraries of DNA and RNA molecules a quarter century ago in the hope of gaining technology that would allow the creation of receptors, ligands, and catalysts on demand. Despite isolated successes, the outputs of this technology have been somewhat disappointing, perhaps because the four building blocks of standard DNA and RNA have too little functionality to have versatile binding properties, and offer too little information density to fold unambiguously. This review covers the recent literature that seeks to create an improved platform to support laboratory Darwinism, one based on an artificially expanded genetic information system (AEGIS that adds independently replicating nucleotide “letters” to the evolving “alphabet”.

  10. Water extraction on Mars for an expanding human colony.

    Science.gov (United States)

    Ralphs, M; Franz, B; Baker, T; Howe, S

    2015-11-01

    In-situ water extraction is necessary for an extended human presence on Mars. This study looks at the water requirements of an expanding human colony on Mars and the general systems needed to supply that water from the martian atmosphere and regolith. The proposed combination of systems in order to supply the necessary water includes a system similar to Honeybee Robotics' Mobile In-Situ Water Extractor (MISWE) that uses convection, a system similar to MISWE but that directs microwave energy down a borehole, a greenhouse or hothouse type system, and a system similar to the Mars Atmospheric Resource Recovery System (MARRS). It is demonstrated that a large water extraction system that can take advantage of large deposits of water ice at site specific locations is necessary to keep up with the demands of a growing colony. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

  11. Thermal excitation spectrum from entanglement in an expanding quantum string

    Directory of Open Access Journals (Sweden)

    Jürgen Berges

    2018-03-01

    Full Text Available A surprising result in e+e− collisions is that the particle spectra from the string formed between the expanding quark–antiquark pair have thermal properties even though scatterings appear not to be frequent enough to explain this. We address this problem by considering the finite observable interval of a relativistic quantum string in terms of its reduced density operator by tracing over the complement region. We show how quantum entanglement in the presence of a horizon in spacetime for the causal transfer of information leads locally to a reduced mixed-state density operator. For very early proper time τ, we show that the entanglement entropy becomes extensive and scales with the rapidity. At these early times, the reduced density operator is of thermal form, with an entanglement temperature Tτ=ħ/(2πkBτ, even in the absence of any scatterings.

  12. PD-1 Blockade Expands Intratumoral Memory T Cells

    DEFF Research Database (Denmark)

    Ribas, Antoni; Shin, Daniel Sanghoon; Zaretsky, Jesse

    2016-01-01

    by multicolor flow cytometry using two computational approaches to resolve the leukocyte phenotypes at the single-cell level. There was a statistically significant increase in the frequency of T cells in patients who responded to therapy. The frequency of intratumoral B cells and monocytic myeloid......-derived suppressor cells significantly increased in patients' biopsies taken on treatment. The percentage of cells with a regulatory T-cell phenotype, monocytes, and natural killer cells did not change while on PD-1 blockade therapy. CD8+ memory T cells were the most prominent phenotype that expanded intratumorally...... on therapy. However, the frequency of CD4+ effector memory T cells significantly decreased on treatment, whereas CD4+ effector T cells significantly increased in nonresponding tumors on therapy. In peripheral blood, an unusual population of blood cells expressing CD56 was detected in two patients...

  13. Battery energy storage market feasibility study -- Expanded report

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, S. [Frost and Sullivan, Mountain View, CA (United States); Akhil, A. [Sandia National Labs., Albuquerque, NM (United States). Energy Storage Systems Analysis and Development Dept.

    1997-09-01

    Under the sponsorship of the US Department of Energy`s Office of Utility Technologies, the Energy Storage Systems Analysis and Development Department at Sandia National Laboratories (SNL) contracted Frost and Sullivan to conduct a market feasibility study of energy storage systems. The study was designed specifically to quantify the battery energy storage market for utility applications. This study was based on the SNL Opportunities Analysis performed earlier. Many of the groups surveyed, which included electricity providers, battery energy storage vendors, regulators, consultants, and technology advocates, viewed battery storage as an important technology to enable increased use of renewable energy and as a means to solve power quality and asset utilization issues. There are two versions of the document available, an expanded version (approximately 200 pages, SAND97-1275/2) and a short version (approximately 25 pages, SAND97-1275/1).

  14. Design and fabrication of multispectral optics using expanded glass map

    Science.gov (United States)

    Bayya, Shyam; Gibson, Daniel; Nguyen, Vinh; Sanghera, Jasbinder; Kotov, Mikhail; Drake, Gryphon; Deegan, John; Lindberg, George

    2015-06-01

    As the desire to have compact multispectral imagers in various DoD platforms is growing, the dearth of multispectral optics is widely felt. With the limited number of material choices for optics, these multispectral imagers are often very bulky and impractical on several weight sensitive platforms. To address this issue, NRL has developed a large set of unique infrared glasses that transmit from 0.9 to > 14 μm in wavelength and expand the glass map for multispectral optics with refractive indices from 2.38 to 3.17. They show a large spread in dispersion (Abbe number) and offer some unique solutions for multispectral optics designs. The new NRL glasses can be easily molded and also fused together to make bonded doublets. A Zemax compatible glass file has been created and is available upon request. In this paper we present some designs, optics fabrication and imaging, all using NRL materials.

  15. Diagnostic imaging in undergraduate medical education: an expanding role

    International Nuclear Information System (INIS)

    Miles, K.A.

    2005-01-01

    Radiologists have been involved in anatomy instruction for medical students for decades. However, recent technical advances in radiology, such as multiplanar imaging, 'virtual endoscopy', functional and molecular imaging, and spectroscopy, offer new ways in which to use imaging for teaching basic sciences to medical students. The broad dissemination of picture archiving and communications systems is making such images readily available to medical schools, providing new opportunities for the incorporation of diagnostic imaging into the undergraduate medical curriculum. Current reforms in the medical curriculum and the establishment of new medical schools in the UK further underline the prospects for an expanding role for imaging in medical education. This article reviews the methods by which diagnostic imaging can be used to support the learning of anatomy and other basic sciences

  16. Macro-economic benefits of an expanded oil sands industry

    International Nuclear Information System (INIS)

    1995-01-01

    Probable impact of benefits of expanded oil sands development on employment and government revenues were analyzed. Investment in proposed oil sands facilities was forecast to create about 1 million person-years of direct and indirect employment. Forty percent of employment gains would be created in Alberta, with remaining positions mostly in Ontario and Quebec. Government taxes, royalties, reduced debts interest costs and revenues to municipalities, hospitals and pension plans would increase by $97 billion (1994 dollars) between 1995 and 2025. Additional benefits would include increases in average Canadian disposable incomes, substitution of imported with domestic oil, and expansion of gross domestic product in Alberta by 5%. Some variation may be expected because of accuracy of assumptions that were made in the analysis, but the character of the results were not expected to change

  17. The economic impact of fluid properties data on expander plants

    International Nuclear Information System (INIS)

    Elliott, D.G.; Chen, J.J.; Brown, T.S.; Sloan, E.D.; Kidnay, A.J.

    1991-01-01

    A number of factors led to design changes that improved the efficiency of expander plants during the 1970's, including the development of equations of state, the desire to increase ethane recoveries and the availability of accurate fluid properties data. The relative importance of fluid properties data in the development of two such design changes - the addition of side reboilers and the use of a subcooled, high-pressure demethanizer - is examined in this paper. simulations of several plants were performed and a comparison of two existing plants was made to estimate the savings in operating and capital costs in these two cases. The savings found far outweigh the cost of acquiring the data that helped to make the design changes possible. This would be of great interest to the petroleum industry in respect to gas processing and production

  18. Time, space, and disorder in the expanding proteome universe.

    Science.gov (United States)

    Minde, David-Paul; Dunker, A Keith; Lilley, Kathryn S

    2017-04-01

    Proteins are highly dynamic entities. Their myriad functions require specific structures, but proteins' dynamic nature ranges all the way from the local mobility of their amino acid constituents to mobility within and well beyond single cells. A truly comprehensive view of the dynamic structural proteome includes: (i) alternative sequences, (ii) alternative conformations, (iii) alternative interactions with a range of biomolecules, (iv) cellular localizations, (v) alternative behaviors in different cell types. While these aspects have traditionally been explored one protein at a time, we highlight recently emerging global approaches that accelerate comprehensive insights into these facets of the dynamic nature of protein structure. Computational tools that integrate and expand on multiple orthogonal data types promise to enable the transition from a disjointed list of static snapshots to a structurally explicit understanding of the dynamics of cellular mechanisms. © 2017 The Authors. Proteomics Published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Dynamical evolution of domain walls in an expanding universe

    Science.gov (United States)

    Press, William H.; Ryden, Barbara S.; Spergel, David N.

    1989-01-01

    Whenever the potential of a scalar field has two or more separated, degenerate minima, domain walls form as the universe cools. The evolution of the resulting network of domain walls is calculated for the case of two potential minima in two and three dimensions, including wall annihilation, crossing, and reconnection effects. The nature of the evolution is found to be largely independent of the rate at which the universe expands. Wall annihilation and reconnection occur almost as fast as causality allows, so that the horizon volume is 'swept clean' and contains, at any time, only about one, fairly smooth, wall. Quantitative statistics are given. The total area of wall per volume decreases as the first power of time. The relative slowness of the decrease and the smoothness of the wall on the horizon scale make it impossible for walls to both generate large-scale structure and be consistent with quadrupole microwave background anisotropy limits.

  20. Expanding entrepreneurship opportunities through local governance: the case of Barbados

    Directory of Open Access Journals (Sweden)

    Paul Pounder

    2015-06-01

    Full Text Available This paper looks at the government and local governance structures of Barbados, arguing that local governance should be leveraged to expand entrepreneurship opportunities at the community level. It examines the links between local governance and entrepreneurship, and proposes a framework aimed at strengthening the relationship between Barbados’ newly formed constituency councils and its government institutions supporting entrepreneurship. The research concludes that there are many inefficiencies in the interaction between government agencies and constituency councils, which the proposed framework is a first step toward remedying.  The research suggests that local governance is a complex issue worldwide. More specifically in Barbados, even though the role of the constituency councils is defined, there are weak formal arrangements which undermine the processes and activities to support community entrepreneurship. The proposed framework highlighted in the research is a first step in formalising a way forward for entrepreneurship in the community. 

  1. Expanding Usability of Virtual Network Laboratory in IT Engineering Education

    Directory of Open Access Journals (Sweden)

    Dalibor M Dobrilovic

    2013-02-01

    Full Text Available This paper deals with importance of virtual network laboratories usage in IT engineering education. It presents the particular virtual network laboratory model developed for usage in Computer Networks course as well. This virtual network laboratory, called VNLab, is based on virtualization technology. It has been successfully tested in educational process of Computer Network course for IT undergraduate students. Its usability for network related courses is analyzed by comparison of recommended curricula’s of world organizations such as IEEE, ACM and AIS. This paper is focused on expanding the usability of this virtual network laboratory to other non-network related courses. The primary expansion field is in domain of IT System Administration, IT Systems and Data Security and Operating Systems as well. The possible learning scenarios, learning tools and concepts for making this system applicable in these three additional fields are presented by the analyses of compatibility with recommended learning topics and outcomes by IEEE, ACM and AIS.

  2. Expanding Group Peer Review: A Proposal for Medical Education Scholarship.

    Science.gov (United States)

    Dumenco, Luba; Engle, Deborah L; Goodell, Kristen; Nagler, Alisa; Ovitsh, Robin K; Whicker, Shari A

    2017-02-01

    After participating in a group peer-review exercise at a workshop presented by Academic Medicine and MedEdPORTAL editors at the 2015 Association of American Medical Colleges Medical Education Meeting, the authors realized that the way their work group reviewed a manuscript was very different from the way by which they each would have reviewed the paper as an individual. Further, the group peer-review process yielded more robust feedback for the manuscript's authors than did the traditional individual peer-review process. This realization motivated the authors to reconvene and collaborate to write this Commentary to share their experience and propose the expanded use of group peer review in medical education scholarship.The authors consider the benefits of a peer-review process for reviewers, including learning how to improve their own manuscripts. They suggest that the benefits of a team review model may be similar to those of teamwork and team-based learning in medicine and medical education. They call for research to investigate this, to provide evidence to support group review, and to determine whether specific paper types would benefit most from team review (e.g., particularly complex manuscripts, those receiving widely disparate initial individual reviews). In addition, the authors propose ways in which a team-based approach to peer review could be expanded by journals and institutions. They believe that exploring the use of group peer review potentially could create a new methodology for skill development in research and scholarly writing and could enhance the quality of medical education scholarship.

  3. Preliminary characterization of an expanding flow of siloxane vapor MDM

    Science.gov (United States)

    Spinelli, A.; Cozzi, F.; Cammi, G.; Zocca, M.; Gaetani, P.; Dossena, V.; Guardone, A.

    2017-03-01

    The early experimental results on the characterization of expanding flows of siloxane vapor MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic VApors (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the pressure, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of pressure and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane vapor MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total pressure of the nozzle are measured upstream of the test section, while static pressure are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the pressure measurement with information about the 2D density gradient field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases

  4. Expanding the Universe of "Astronomy on Tap" Public Outreach Events

    Science.gov (United States)

    Rice, Emily L.; Levine, Brian; Livermore, Rachael C.; Silverman, Jeffrey M.; LaMassa, Stephanie M.; Tyndall, Amy; Muna, Demitri; Garofali, Kristen; Morris, Brett; Byler, Nell; Fyhrie, Adalyn; Rehnberg, Morgan; Hart, Quyen N.; Connelly, Jennifer L.; Silvia, Devin W.; Morrison, Sarah J.; Agarwal, Bhaskar; Tremblay, Grant; Schwamb, Megan E.

    2016-01-01

    Astronomy on Tap (AoT, astronomyontap.org) is free public outreach event featuring engaging science presentations in bars, often combined with music, games, and prizes, to encourage a fun, interactive atmosphere. AoT events feature several short astronomy-related presentations primarily by local professional scientists, but also by visiting scientists, students, educators, amatuer astronomers, writers, and artists. Events are held in social venues (bars, coffee shops, art galleries, etc.) in order to bring science directly to the public in a relaxed, informal atmosphere. With this we hope to engage a more diverse audience than typical lectures at academic and cultural institutions and to develop enthusiasm for science among voting, tax-paying adults. The flexible format and content of an AoT event is easy to adapt and expand based on the priorities, resources, and interests of local organizers. The social nature of AoT events provides important professional development and networking opportunities in science communication. Since the first New York City event in April 2013, Astronomy on Tap has expanded to more than ten cities globally, including monthly events in NYC, Austin, Seattle, and Tucson; semi-regular events in Columbus, New Haven, Santiago, Toronto, and Denver; occasional (so far) events in Rochester (NY), Baltimore, Lansing, and Washington, DC; and one-off events in Chicago and Taipei. Several venues regularly attract audiences of over 200 people. We have received media coverage online, in print, and occasionally even on radio and television. In this poster we describe the overarching goals and characteristics of AoT events, distinct adaptations of various locations, resources we have developed, and the methods we use to coordinate among the worldwide local organizers.

  5. Retuning Rieske-type Oxygenases to Expand Substrate Range

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Mahmood; Viger, Jean-François; Kumar, Pravindra; Barriault, Diane; Bolin, Jeffrey T.; Sylvestre, Michel (INRS); (Purdue)

    2012-09-17

    Rieske-type oxygenases are promising biocatalysts for the destruction of persistent pollutants or for the synthesis of fine chemicals. In this work, we explored pathways through which Rieske-type oxygenases evolve to expand their substrate range. BphAE{sub p4}, a variant biphenyl dioxygenase generated from Burkholderia xenovorans LB400 BphAE{sub LB400} by the double substitution T335A/F336M, and BphAE{sub RR41}, obtained by changing Asn{sup 338}, Ile{sup 341}, and Leu{sup 409} of BphAE{sub p4} to Gln{sup 338}, Val{sup 341}, and Phe{sup 409}, metabolize dibenzofuran two and three times faster than BphAE{sub LB400}, respectively. Steady-state kinetic measurements of single- and multiple-substitution mutants of BphAE{sub LB400} showed that the single T335A and the double N338Q/L409F substitutions contribute significantly to enhanced catalytic activity toward dibenzofuran. Analysis of crystal structures showed that the T335A substitution relieves constraints on a segment lining the catalytic cavity, allowing a significant displacement in response to dibenzofuran binding. The combined N338Q/L409F substitutions alter substrate-induced conformational changes of protein groups involved in subunit assembly and in the chemical steps of the reaction. This suggests a responsive induced fit mechanism that retunes the alignment of protein atoms involved in the chemical steps of the reaction. These enzymes can thus expand their substrate range through mutations that alter the constraints or plasticity of the catalytic cavity to accommodate new substrates or that alter the induced fit mechanism required to achieve proper alignment of reaction-critical atoms or groups.

  6. New kaolinite phases expanded through intercalation with potassium acetate

    International Nuclear Information System (INIS)

    Frost, R.L.; Kristof, J.; Kloprogge, J.T.

    1998-01-01

    Full text: Changes in the hydroxyl surfaces of potassium acetate-intercalated kaolinite have been studied over the ambient to predehydroxylation temperature range using a combination of X-ray diffraction and Raman spectroscopy. Upon intercalation, the kaolinite expanded along the c-axis direction to 13.88 Angstroms. Upon heating the intercalation complex over the 50 to 300 deg C range, X-ray diffraction shows the existence of three additional intercalation phases with d-spacings of 9.09, 9.60, and 11.47 Angstroms. The amount of each phase is temperature dependent. These expansions are reversible and upon cooling the intercalation complex returned to its original spacing. The 13.88 Angstroms phase only existed in the presence of water. It is proposed that the expanded kaolinite intercalation phases result from the orientation of the acetate within the intercalation complex. The Raman spectra of the hydroxyl-stretching region (Frost and van der Gaast, 1997) of potassium acetate-intercalated kaolinite has been obtained under an atmosphere of both air and nitrogen using a thermal stage over the 25 to 300 deg C temperature range (Johansson et al., 1998). Raman spectra of the C-C, C=O stretching and O-C-O bending modes show that at least two types of acetate are present in the intercalation complex. These are assigned to two different orientations of the acetate. At 25 deg C, a new band at 3606 cm -1 attributed to the inner surface hydroxyl hydrogen bonded to the acetate ion is observed with a concomitant loss of intensity in the bands attributed to the inner surface hydroxyls (Frost and Kristof, 1997, Frost et al.,1997). Heating the intercalation complex to 50 deg C results in two hydroxyl-stretching frequencies at 3594 and 3604 cm -1 . This change in frequencies is ascribed to phase changes of the potassium acetate-intercalated kaolinite. At 100 deg C, the bands shift to 3600 and 3613 cm -1 . These shifts in frequencies are assigned to new kaolinite expanded phases. At

  7. Quality Control for Expanded Tsetse Production, Sterilization and Field Application

    International Nuclear Information System (INIS)

    2012-07-01

    The use of the sterile insect technique (SIT) for the control of pest insects as part of an integrated, area-wide approach is widely accepted. Its application for the eradication of different tsetse flies, the vectors of human sleeping sickness and African animal trypanosomosis, is attracting increasing interest. Following several initial demonstrations of the application of the SIT for tsetse control the technique was applied on the island of Unguja, Zanzibar, in the mid-1990s and, as the final component of an integrated control programme, led to the eradication of the only tsetse species on the island, Glossina austeni. This successful programme encouraged a number of countries to embark on projects with an SIT component for tsetse control, most Ethiopia. In 2001 the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) was launched by the Organization of African Unity (now African Union, AU) and, subsequently, six countries obtained funding from the African Development Bank (AfDB) in 2005 to support control programmes with an SIT component. A further six countries have subsequently requested AfDB funding for their programmes. The FAO/IAEA coordinated research project (CRP) on Automation for Tsetse Mass Rearing For Use in Sterile Insect Technique Programmes, which was completed in 2001, led to the development of a semi-automated system for tsetse production. Using this new system, a large rearing facility was established in Addis Ababa, Ethiopia, to supply sterile males for an elimination programme in the southern Rift Valley. The development of large-scale rearing highlighted the need for improved quality control procedures and, with this in mind, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture established a CRP in 2003 entitled Improved and Harmonized Quality Control for Expanded Tsetse Production, Sterilization and Field Application with the Objective of Improving and Expanding the Quality Control Sections of the FAO

  8. Expanding Canada Pension Plan Retirement Benefits: Assessing Big CPP Proposals

    Directory of Open Access Journals (Sweden)

    Jonathan R. Kesselman

    2010-10-01

    Full Text Available Current and growing deficiencies in many workers’ ability to maintain their accustomed living standards in retirement have evoked varied proposals for reform of Canada’s retirement income system. This study focuses on proposals for expanding the retirement benefits of the Canada Pension Plan (CPP, and undertakes comparative analysis with proposals for reforms affecting workplace pensions and individual savings. It begins by reviewing key policy questions for the retirement income system and describing essential features of several proposals for CPP benefit expansion. It then uses these “Big CPP” proposals as a basis to assess the design issues for expanding CPP benefits and the implications for other components of the retirement income system. The paper assesses each of the major private and public savings vehicles based on multifaceted criteria for a well-performing retirement income system; a mandatory public scheme with defined benefits ranks most highly on almost all criteria other than individual flexibility. Additional behavioural and institutional factors also support the use of mandatory public pensions: myopia in savings, individual investment behaviour, scale economies and costs of fund management, adverse selection and annuitization costs, the Samaritan’s Dilemma, and labour market incentives. The study provides an overview analysis of key design issues for the expansion of CPP retirement benefits. Major issues include the desirable scale of expansion for both the percentage of insurable earnings and the insurable earnings ceiling; mandatory versus voluntary coverage and options; the allocation of investment return risk; and the phasing-in of higher premiums and benefits. The study then assesses the implications of CPP expansion for other components of the retirement income system: Old Age Security and the Guaranteed Income Supplement, workplace pensions, tax provisions for savings, and individual savings. A Big CPP fits

  9. Quality Control for Expanded Tsetse Production, Sterilization and Field Application

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-15

    The use of the sterile insect technique (SIT) for the control of pest insects as part of an integrated, area-wide approach is widely accepted. Its application for the eradication of different tsetse flies, the vectors of human sleeping sickness and African animal trypanosomosis, is attracting increasing interest. Following several initial demonstrations of the application of the SIT for tsetse control the technique was applied on the island of Unguja, Zanzibar, in the mid-1990s and, as the final component of an integrated control programme, led to the eradication of the only tsetse species on the island, Glossina austeni. This successful programme encouraged a number of countries to embark on projects with an SIT component for tsetse control, most Ethiopia. In 2001 the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) was launched by the Organization of African Unity (now African Union, AU) and, subsequently, six countries obtained funding from the African Development Bank (AfDB) in 2005 to support control programmes with an SIT component. A further six countries have subsequently requested AfDB funding for their programmes. The FAO/IAEA coordinated research project (CRP) on Automation for Tsetse Mass Rearing For Use in Sterile Insect Technique Programmes, which was completed in 2001, led to the development of a semi-automated system for tsetse production. Using this new system, a large rearing facility was established in Addis Ababa, Ethiopia, to supply sterile males for an elimination programme in the southern Rift Valley. The development of large-scale rearing highlighted the need for improved quality control procedures and, with this in mind, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture established a CRP in 2003 entitled Improved and Harmonized Quality Control for Expanded Tsetse Production, Sterilization and Field Application with the Objective of Improving and Expanding the Quality Control Sections of the FAO

  10. On the electric and magnetic field generation in expanding plasmas

    International Nuclear Information System (INIS)

    Gielen, H.J.G.

    1989-01-01

    This thesis deals with the generation of electric and magnetic fields in expanding plasmas. The theoretical model used to calculate the different field quantities in such plasmas is discussed in part 1 and is in fact an analysis of Ohm's law. A general method is given that decomposes each of the forces terms in Ohm's law in a component that induces a charge separation in the plasma and in a component that can drive current. This decomposition is unambiguous and depends upon the boundary conditions for the electric potential. It is shown that in calculating the electromagnetic field quantities in a plasma that is located in the vicinity of a boundary that imposes constraints on the electric potential, Ohm's law should be analyzed instead of the so-called induction equation. Three applications of the model are presented. A description is given of the unipolar arc discharge where both plasma and sheath effects have been taken into account. Secondly a description is presented of the plasma effects of a cathode spot. The third application of the model deals with the generation of magnetic fields in laser-produced plasmas. The second part of this thesis describes the experiments on a magnetized argon plasma expanding from a cascaded arc. With the use of spectroscopic techniques the electron density, ion temperature and the rotation velocity profiles of the ion gas have been determined. The magnetic field generated by the plasma has been measured with the use of the Zeeman effect. Depending on the channel diameter of the nozzle of the cascaded arc, self-generated magnetic fields with axial components of the order of 1% of the externally applied mangetic field have been observed. From the measured ion rotation it has been concluded that this magnetic field is mainly generated by azimuthal electron currents. The corresponding azimuthal current density is of the order of 15% of the axial current density. The observed ion rotation is caused by electron-ion friction. (author

  11. Proton dynamics in lithium-ammonia solutions and expanded metals.

    Science.gov (United States)

    Thompson, Helen; Skipper, Neal T; Wasse, Jonathan C; Spencer Howells, W; Hamilton, Myles; Fernandez-Alonso, Felix

    2006-01-14

    Quasielastic neutron scattering has been used to study proton dynamics in the system lithium-ammonia at concentrations of 0, 4, 12, and 20 mole percent metal (MPM) in both the liquid and solid (expanded metal) phases. At 230 K, in the homogenous liquid state, we find that the proton self-diffusion coefficient first increases with metal concentration, from 5.6x10(-5) cm2 s(-1) in pure ammonia to 7.8x10(-5) cm2 s(-1) at 12 MPM. At higher concentrations we note a small decrease to a value of 7.0x10(-5) cm2 s(-1) at 20 MPM (saturation). These results are consistent with NMR data, and can be explained in terms of the competing influences of the electron and ion solvation. At saturation, the solution freezes to form a series of expanded metal compounds of composition Li(NH3)4. Above the melting point, at 100 K, we are able to fit our data to a jump-diffusion model, with a mean jump length (l) of 2.1 A and residence time (tau) of 3.1 ps. This model gives a diffusion coefficient of 2.3x10(-5) cm2 s(-1). In solid phase I (cubic, stable from 88.8 to 82.2 K) we find that the protons are still undergoing this jump diffusion, with l=2.0 A and tau=3.9 ps giving a diffusion coefficient of 1.8x10(-5) cm2 s(-1). Such motion gives way to purely localized rotation in solid phases IIa (from 82.2 to 69 K) and IIb (stable from 69 to 25 K). We find rotational correlation times (tau(rot)) of the order of 2.0 and 7.3 ps in phases IIa and IIb, respectively. These values can be compared with a rotational mode in solid ammonia with tau(rot) approximately 2.4 ps at 150 K.

  12. Smoothed particle hydrodynamic simulations of expanding HII regions

    Science.gov (United States)

    Bisbas, Thomas G.

    2009-09-01

    This thesis deals with numerical simulations of expanding ionized regions, known as HII regions. We implement a new three dimensional algorithm in Smoothed Particle Hydrodynamics for including the dynamical effects of the interaction between ionizing radiation and the interstellar medium. This interaction plays a crucial role in star formation at all epochs. We study the influence of ionizing radiation in spherically symmetric clouds. In particular, we study the spherically symmetric expansion of an HII region inside a uniform-density, non-self-gravitating cloud. We examine the ability of our algorithm to reproduce the known theoretical solution and we find that the agreement is very good. We also study the spherically symmetric expansion inside a uniform-density, self-gravitating cloud. We propose a new differential equation of motion for the expanding shell that includes the effects of gravity. Comparing its numerical solution with the simulations, we find that the equation predicts the position of the shell accurately. We also study the expansion of an off-centre HII region inside a uniform-density, non- self-gravitating cloud. This results in an evolution known as the rocket effect, where the ionizing radiation pushes and accelerates the cloud away from the exciting star leading to its dispersal. During this evolution, cometary knots appear as a result of Rayleigh-Taylor and Vishniac instabilities. The knots are composed of a dense head with a conic tail behind them, a structure that points towards the ionizing source. Our simulations show that these knots are very reminiscent of the observed structures in planetary nebula, such as in the Helix nebula. The last part of this thesis is dedicated to the study of cores ionized by an exciting source which is placed outside and far away from them. The evolution of these cores is known as radiation driven compression (or implosion). We perform simulations and compare our findings with results of other workers and we

  13. A modern mode of activation for nucleic acid enzymes.

    Directory of Open Access Journals (Sweden)

    Dominique Lévesque

    2007-07-01

    Full Text Available Through evolution, enzymes have developed subtle modes of activation in order to ensure the sufficiently high substrate specificity required by modern cellular metabolism. One of these modes is the use of a target-dependent module (i.e. a docking domain such as those found in signalling kinases. Upon the binding of the target to a docking domain, the substrate is positioned within the catalytic site. The prodomain acts as a target-dependent module switching the kinase from an off state to an on state. As compared to the allosteric mode of activation, there is no need for the presence of a third partner. None of the ribozymes discovered to date have such a mode of activation, nor does any other known RNA. Starting from a specific on/off adaptor for the hepatitis delta virus ribozyme, that differs but has a mechanism reminiscent of this signalling kinase, we have adapted this mode of activation, using the techniques of molecular engineering, to both catalytic RNAs and DNAs exhibiting various activities. Specifically, we adapted three cleaving ribozymes (hepatitis delta virus, hammerhead and hairpin ribozymes, a cleaving 10-23 deoxyribozyme, a ligating hairpin ribozyme and an artificially selected capping ribozyme. In each case, there was a significant gain in terms of substrate specificity. Even if this mode of control is unreported for natural catalytic nucleic acids, its use needs not be limited to proteinous enzymes. We suggest that the complexity of the modern cellular metabolism might have been an important selective pressure in this evolutionary process.

  14. New DEA rules expand options for controlled substance disposal.

    Science.gov (United States)

    Peterson, David M

    2015-03-01

    Prescription drug abuse and overdose are rapidly growing problems in the United States. The United States federal Disposal of Controlled Substances Rule became effective 9 October 2014, implementing the Secure and Responsible Drug Disposal Act of 2010 (Disposal Act). These regulations target escalating prescription drug misuse by reducing accumulation of unused controlled substances that may be abused, diverted or accidentally ingested. Clinical areas that can now participate in collecting unused controlled substances include retail pharmacies, hospitals or clinics with an onsite pharmacy, and narcotic treatment programs. Collection methods include placing a controlled substance collection receptacle or instituting a mail-back program. Because prompt onsite destruction of collected items is required of mail-back programs, collection receptacles are more likely to be used in clinical areas. Retail pharmacies and hospitals or clinics with an onsite pharmacy may also place and maintain collection receptacles at long-term care facilities. The Act and Rule are intended to increase controlled substance disposal methods and expand local involvement in collection of unused controlled substances. Potential barriers to participating in controlled substance collection include acquisition of suitable collection receptacles and liners, lack of available space meeting the necessary criteria, lack of employee time for verification and inventory requirements, and program costs.

  15. Science with the Expanded Owens Valley Solar Array

    Science.gov (United States)

    Nita, Gelu M.; Gary, Dale E.; Fleishman, Gregory D.; Chen, Bin; White, Stephen M.; Hurford, Gordon J.; McTiernan, James; Hickish, Jack; Yu, Sijie; Nelin, Kjell B.

    2017-08-01

    The Expanded Owens Valley Solar Array (EOVSA) is a solar-dedicated radio array that makes images and spectra of the full Sun on a daily basis. Our main science goals are to understand the basic physics of solar activity, such as how the Sun releases stored magnetic energy on timescales of seconds, and how that solar activity, in the form of solar flares and coronal mass ejections, influences the Earth and near-Earth space environment, through disruptions of communication and navigation systems, and effects on satellites and systems on the ground. The array, which is composed out of thirteen 2.1 m dishes and two 27 m dishes (used only for calibration), has a footprint of 1.1 km EW x 1.2 km NS and it is capable of producing, every second, microwave images at two polarizations and 500 science channels spanning the 1-18 GHz frequency range. Such ability to make multi-frequency images of the Sun in this broad range of frequencies, with a frequency dependent resolution ranging from ˜53” at 1 GHz to ˜3”at 18 GHz, is unique in the world. Here we present an overview of the EOVSA instrument and a first set of science-quality active region and solar flare images produced from data taken during April 2017.This research is supported by NSF grant AST-1615807 and NASA grant NNX14AK66G to New Jersey Institute of Technology.

  16. Potential to expand sustainable bioenergy from sugarcane in southern Africa

    International Nuclear Information System (INIS)

    Watson, Helen K.

    2011-01-01

    The Cane Resources Network for Southern Africa evaluated how bioenergy from sugarcane can support sustainable development and improve global competitiveness in the region. The assessment of six countries with good contemporary potential for expanding sugarcane cultivation described in this paper was part of their analysis. Its principal objective was to identify land where such production will not have detrimental environmental and/or socio-economic impacts. Geographic Information Systems (GIS) was used to interrogate 1 km 2 resolution protected area, land cover, climate, elevation and soil data sets. To avoid detrimental impacts on biodiversity, all categories of protected areas, closed canopy forests and wetlands were excluded. To safeguard food security, all areas under food and/or cash crop production were excluded. Areas unsuitable because of climate, terrain and soil constraints were also excluded. The assessment found that almost 6 million hectares of suitable land is available in these countries, clearly suggesting that 'land' is unlikely to be a limiting factor in harnessing sugarcane's bioenergy potential in the region. However, land identified as such in this study needs to be verified using better resolution, preferably ground, information.

  17. Expanding plasmas from anti de Sitter black holes

    Energy Technology Data Exchange (ETDEWEB)

    Camilo, Giancarlo [Instituto de Fisica, Universidade de Sao Paulo, Departamento de Fisica Matematica, Sao Paulo (Brazil)

    2016-12-15

    We introduce a new foliation of AdS{sub 5} black holes such that the conformal boundary takes the form of a 4-dimensional FLRW spacetime with scale factor a(t). The foliation employs Eddington-Finkelstein-like coordinates and is applicable to a large class of AdS black holes, supported by matter fields or not, considerably extending previous efforts in the literature. We argue that the holographic dual picture of a CFT plasma on a FLRW background provides an interesting prototype to study the nonequilibrium dynamics of expanding plasmas and use holographic renormalization to extract the renormalized energy-momentum tensor of the dual plasma. We illustrate the procedure for three black holes of interest, namely AdS-Schwarzschild, AdS-Gauss-Bonnet, and AdS-Reissner-Nordstroem. For the latter, as a by-product, we show that the nonequilibrium dynamics of a CFT plasma subject to a quench in the chemical potential (i.e., a time-dependent chemical potential) resembles a cosmological evolution with the scale factor a(t) being inversely related to the quench profile μ(t). (orig.)

  18. Expanding U.S. markets for Canadian crude oil

    International Nuclear Information System (INIS)

    Heath, M.; Angevine, G.; Chan, K.; Renne, G.; Stariha, J.; MacKay, E.

    1993-01-01

    The quantities and types of Canadian, U.S. and competing foreign crudes flowing into U.S. market regions and the potential to retain and/or expand Canadian crude oil sales in each of those markets, was studied. The various pipeline system expansion/construction proposals were reviewed. Findings of the study with respect to prospects for crude oil sales into each of the U.S. market regions were presented. Opportunities and constraints with regard to the potential for incremental crude oil sales into each of the U.S. market regions were detailed. The study concluded that there was a substantial market in the U.S. for incremental sales of Canadian crudes. Most of the refineries in the U.S. market regions were more flexible in terms of their crude diet than they were before the rationalization and restructuring of the industry began. The market for crude oil in the U.S. was shown to be one of the most competitive in the world and the most volatile. The study also revealed that there were risks associated with large additions to the capacity to ship crude oil by pipeline from Western Canada, given the uncertainties surrounding future supply. 4 refs., figs., tabs

  19. Kinesin expands and stabilizes the GDP-microtubule lattice

    Science.gov (United States)

    Peet, Daniel R.; Burroughs, Nigel J.; Cross, Robert A.

    2018-05-01

    Kinesin-1 is a nanoscale molecular motor that walks towards the fast-growing (plus) ends of microtubules, hauling molecular cargo to specific reaction sites in cells. Kinesin-driven transport is central to the self-organization of eukaryotic cells and shows great promise as a tool for nano-engineering1. Recent work hints that kinesin may also play a role in modulating the stability of its microtubule track, both in vitro2,3 and in vivo4, but the results are conflicting5-7 and the mechanisms are unclear. Here, we report a new dimension to the kinesin-microtubule interaction, whereby strong-binding state (adenosine triphosphate (ATP)-bound and apo) kinesin-1 motor domains inhibit the shrinkage of guanosine diphosphate (GDP) microtubules by up to two orders of magnitude and expand their lattice spacing by 1.6%. Our data reveal an unexpected mechanism by which the mechanochemical cycles of kinesin and tubulin interlock, and so allow motile kinesins to influence the structure, stability and mechanics of their microtubule track.

  20. Is the number of photons conserved in an expanding universe

    International Nuclear Information System (INIS)

    Novello, M.; Oliveira, L.A.R. de; Salim, J.M.

    1988-01-01

    A Friedman - like scenario in which - due to gravitational interaction - the total number of photons existing in the Universe changes as the Universe expands, is described. The photon number distribution function, in thermal equilibrium, exhibits an explicit dependence on a non-vanishing chemical potential term. This non-null value for the chemical potential of the photon is due to the presence of tidal effects, arising from the direct coupling of the photons - which, in a gravitational field, should not be treated as idealized point-like objects - to the curvature of space-time. As a result, the ratio nγ/n B between the numbers of photons and baryons in the Universe is shown to be not a constat, but rather a function of cosmic time, vanishing when the singularity of the standard FRW model is reached. In consequence, some of the supposed 'fundamental problems' of standard Cosmology (e.g., the explanation of the constancy of the ration nγ/n B and thus of the origin fo the total ammount of entropy observed today) are but apparent ones in the present scenario, and may be ipso facto solved. (author) [pt

  1. Discordant introgression in a rapidly expanding hybrid swarm

    Science.gov (United States)

    Ward, Jessica L.; Blum, Mike J.; Walters, David M.; Porter, Brady A.; Burkhead, Noel; Freeman, Byron

    2012-01-01

    The erosion of species boundaries can involve rapid evolutionary change. Consequently, many aspects of the process remain poorly understood, including the formation, expansion, and evolution of hybrid swarms. Biological invasions involving hybridization present exceptional opportunities to study the erosion of species boundaries because timelines of interactions and outcomes are frequently well known. Here, we examined clinal variation across codominant and maternally inherited genetic markers as well as phenotypic traits to characterize the expansion and evolution of a hybrid swarm between native Cyprinella venusta and invasive Cyprinella lutrensis minnows. Discordant introgression of phenotype, microsatellite multilocus genotype, and mtDNA haplotype indicates that the observable expansion of the C. venusta x C. lutrensis hybrid swarm is a false invasion front. Both parental and hybrid individuals closely resembling C. lutrensis are numerically dominant in the expansion wake, indicating that the non-native parental phenotype may be selectively favored. These findings show that cryptic introgression can extend beyond the phenotypic boundaries of hybrid swarms and that hybrid swarms likely expand more rapidly than can be documented from phenotypic variation alone. Similarly, dominance of a single parental phenotype following an introduction event may lead to instances of species erosion being mistaken for species displacement without hybridization.

  2. Initiation of a boiling liquid expanding vapour explosion

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, C.A.; Chan, C.K.; Steward, F.R.; Tennankore, K.N.; Venart, J.E.S.

    1991-06-01

    Boiling liquid expanding vapour explosions (BLEVEs) occur when a pressure liquefied gas tank is burst and the fluid is ejected to the atmosphere. As the liquid is exposed to a lower pressure it boils violently, causing an explosion which destroys the container. One litre tanks were filled with propane or R12, heated, and caused to rupture at specific test conditions to determine the parameters required for a BLEVE. Results showed that the energy stored in the liquid under pressure relative to the liquid at atmospheric conditions was a quantity which can be used to predict a BLEVE for the particular apparatus and conditions used. The possible importance of the development of a shock wave within the container during a BLEVE was noted. A shock tube was used to study the shock waves generated during a BLEVE. Temperature, liquid volume, rupture location, rupture area, and the fluid involved were varied. The pressure was measured vs time for periods immediately after the rupture. Photographs of the formation of pressure waves were obtained using spark Schlieren photography and showed that the BLEVE phenomenon is definitely a shock-related event. Pressure information was also gathered during BLEVEs of one litre cylinders, and this information is compared to that from the shock tube. Shock tube data showed that transverse waves formed from the initial pressure wave could be amplified. 37 refs., 54 figs., 11 tabs.

  3. The Expanded Public Works Programme: Perspectives of direct beneficiaries

    Directory of Open Access Journals (Sweden)

    Mondli S. Hlatshwayo

    2017-09-01

    Full Text Available Scholarship on the Expanded Public Works Programme (EPWP in South Africa tends to focus on quantitative evaluation to measure the progress made in the implementation of EPWP projects. The number of employment opportunities created by EPWP, demographic profiling, skills acquired by beneficiaries and training opportunities related to the Programme form the basis of typical statistical evaluations of it, but exclude comment by the workers who participate in its projects. Based on primary sources, including in-depth interviews, newspaper reports and internet sources, this article seeks to provide a qualitative review of the EPWP from the perspective of the beneficiaries of municipal EPWP projects. Various South African government sectors hire EPWP workers to provide local services such as cleaning and maintaining infrastructure, but the employment of these workers can still be regarded as precarious, in the sense that they have no job security, earn low wages and have no benefits such as medical aid or pension fund. The interviewees indicated that, although they appreciate the temporary employment opportunities provided by the EPWP, they also experience health and safety risks and lack the advantages of organised labour groupings. Their main disadvantage, however, is that they cannot access permanent employment, which offers better wages and concomitant benefits.

  4. Repair of large abdominal wall defects with expanded polytetrafluoroethylene (PTFE).

    Science.gov (United States)

    Bauer, J J; Salky, B A; Gelernt, I M; Kreel, I

    1987-01-01

    Most abdominal wall incisional hernias can be repaired by primary closure. However, where the defect is large or there is tension on the closure, the use of a prosthetic material is indicated. Expanded polytetrafluoroethylene (PTFE) patches were used to repair incisional hernias in 28 patients between November 1983 and December 1986. Twelve of these patients (43%) had a prior failure of a primary repair. Reherniation occurred in three patients (10.7%). Wound infections developed in two patients (7.1%), both of whom had existing intestinal stomas, one with an intercurrent pelvic abscess. The prosthetic patch was removed in the patient with the abscess, but the infection was resolved in the other without sequelae. Septic complications did not occur after any operations performed in uncontaminated fields. None of the patients exhibited any undue discomfort, wound pain, erythema, or induration. Complications related to adhesions, erosion of the patch material into the viscera, bowel obstruction, or fistula formation did not occur. Based on this clinical experience, the authors believe that the PTFE patch appears to represent an advance in synthetic abdominal wall substitutes. Images Fig. 1. Fig. 2(left)., Fig. 3(right). PMID:3689012

  5. Linear response formula for piecewise expanding unimodal maps

    Science.gov (United States)

    Baladi, Viviane; Smania, Daniel

    2008-04-01

    The average R(t)=\\int \\varphi\\,\\rmd \\mu_t of a smooth function phiv with respect to the SRB measure μt of a smooth one-parameter family ft of piecewise expanding interval maps is not always Lipschitz (Baladi 2007 Commun. Math. Phys. 275 839-59, Mazzolena 2007 Master's Thesis Rome 2, Tor Vergata). We prove that if ft is tangent to the topological class of f, and if ∂t ft|t = 0 = X circle f, then R(t) is differentiable at zero, and R'(0) coincides with the resummation proposed (Baladi 2007) of the (a priori divergent) series \\sum_{n=0}^\\infty \\int X(y) \\partial_y (\\varphi \\circ f^n)(y)\\,\\rmd \\mu_0(y) given by Ruelle's conjecture. In fact, we show that t map μt is differentiable within Radon measures. Linear response is violated if and only if ft is transversal to the topological class of f.

  6. Functional evolution of new and expanded attention networks in humans.

    Science.gov (United States)

    Patel, Gaurav H; Yang, Danica; Jamerson, Emery C; Snyder, Lawrence H; Corbetta, Maurizio; Ferrera, Vincent P

    2015-07-28

    Macaques are often used as a model system for invasive investigations of the neural substrates of cognition. However, 25 million years of evolution separate humans and macaques from their last common ancestor, and this has likely substantially impacted the function of the cortical networks underlying cognitive processes, such as attention. We examined the homology of frontoparietal networks underlying attention by comparing functional MRI data from macaques and humans performing the same visual search task. Although there are broad similarities, we found fundamental differences between the species. First, humans have more dorsal attention network areas than macaques, indicating that in the course of evolution the human attention system has expanded compared with macaques. Second, potentially homologous areas in the dorsal attention network have markedly different biases toward representing the contralateral hemifield, indicating that the underlying neural architecture of these areas may differ in the most basic of properties, such as receptive field distribution. Third, despite clear evidence of the temporoparietal junction node of the ventral attention network in humans as elicited by this visual search task, we did not find functional evidence of a temporoparietal junction in macaques. None of these differences were the result of differences in training, experimental power, or anatomical variability between the two species. The results of this study indicate that macaque data should be applied to human models of cognition cautiously, and demonstrate how evolution may shape cortical networks.

  7. An expanded dengue syndrome patient with manifestation myocarditis: case report

    Science.gov (United States)

    Arifijanto, M. V.; Luqmana, H. P.; Rusli, M.; Bramantono

    2018-03-01

    Dengue infection may manifest asymptomatic, dengue fever, dengue hemorrhagic fever, dengue shock syndrome. However, atypical manifestations in other organs have been increasingly reported and called expanded dengue syndrome. One of the cardiac complications in dengue is myocarditis. An 18-year-old woman complains of high fever since 3 days, epistaxis, chest pain, dyspnea, and vomiting. Laboratory examination obtained thrombocytopenia, hemoconcentration, NS1, IgG-IgM dengue positive, CKMB and Troponin- I increase. Electrocardiogram result ischemic anterior-posterior. Echocardiography results hyperechogenic on myocardial suspicious a myocarditis. The patient was diagnosed with acute myocarditis and dengue hemorrhagic fever. Condition improved after five days of treatment. Cardiac complications in dengue are now increasingly observed with the most common case is myocarditis. The main mechanism of dengue myocarditis is still unknown though both direct viral infection and immune mediated damage have been suggested to be the cause of myocardial damage. The low incidence of dengue myocarditis is because it’s asymptomatic and diagnosis is easily missed. Almost all cases of dengue myocarditis are self-limiting and severe myocarditis leading to dilated cardiomyopathy is extremely rare. There have been reported a patient with dengue hemorrhagic fever with manifestation myocarditis. Condition improve with supportive management.

  8. Rotavirus vaccination within the South African Expanded Programme on Immunisation.

    Science.gov (United States)

    Seheri, L Mapaseka; Page, Nicola A; Mawela, Mothahadini P B; Mphahlele, M Jeffrey; Steele, A Duncan

    2012-09-07

    Diarrhoeal diseases are ranked the third major cause of childhood mortality in South African children less than 5 years, where the majority of deaths are among black children. Acute severe dehydrating rotavirus diarrhoea remains an important contributor towards childhood mortality and morbidity and has been well documented in South Africa. As the preventive strategy to control rotavirus diarrhoea, South Africa became the first country in the WHO African Region to adopt the rotavirus vaccine in the national childhood immunisation programme in August 2009. The rotavirus vaccine in use, Rotarix, GSK Biologicals, is given at 6 and 14 weeks of age, along with other vaccines as part of Expanded Programme on Immunisation (EPI). Studies which facilitated the introduction of rotavirus vaccine in South Africa included the burden of rotavirus disease and strain surveillance, economic burden of rotavirus infection and clinical trials to assess the safety and efficacy of vaccine candidates. This paper reviews the epidemiology of rotavirus in South Africa, outlines some of the steps followed to introduce rotavirus vaccine in the EPI, and highlights the early positive impact of vaccination in reducing the rotavirus burden of disease based on the post-marketing surveillance studies at Dr George Mukhari hospital, a sentinel site at University of Limpopo teaching hospital in Pretoria, South Africa, which has conducted rotavirus surveillance for >20 years. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Expanding the mutation and clinical spectrum of Roberts syndrome.

    Science.gov (United States)

    Afifi, Hanan H; Abdel-Salam, Ghada M H; Eid, Maha M; Tosson, Angie M S; Shousha, Wafaa Gh; Abdel Azeem, Amira A; Farag, Mona K; Mehrez, Mennat I; Gaber, Khaled R

    2016-07-01

    Roberts syndrome and SC phocomelia syndrome are rare autosomal recessive genetic disorders representing the extremes of the spectrum of severity of the same condition, caused by mutations in ESCO2 gene. We report three new patients with Roberts syndrome from three unrelated consanguineous Egyptian families. All patients presented with growth retardation, mesomelic shortening of the limbs more in the upper than in the lower limbs and microcephaly. Patients were subjected to clinical, cytogenetic and radiologic examinations. Cytogenetic analysis showed the characteristic premature separation of centromeres and puffing of heterochromatic regions. Further, sequencing of the ESCO2 gene identified a novel mutation c.244_245dupCT (p.T83Pfs*20) in one family besides two previously reported mutations c.760_761insA (p.T254Nfs*27) and c.764_765delTT (p.F255Cfs*25). All mutations were in homozygous state, in exon 3. The severity of the mesomelic shortening of the limbs and craniofacial anomalies showed variability among patients. Interestingly, patient 1 had abnormal skin hypopigmentation. Serial fetal ultrasound examinations and measurements of long bones diagnosed two affected fetuses in two of the studied families. A literature review and case comparison was performed. In conclusion, we report a novel ESCO2 mutation and expand the clinical spectrum of Roberts syndrome. © 2015 Japanese Teratology Society.

  10. Adsorption Characteristics of Polyvinyl Alcohols in Solution on Expanded Graphite

    Directory of Open Access Journals (Sweden)

    Xiu-Yan Pang

    2012-01-01

    Full Text Available Expanded graphite (EG adsorbent was prepared with 50 mesh graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Three kinds of polyvinyl alcohol (PVA with different degree of polymerization (DP in aqueous solution were used as adsorbates. We have studied the influence of initial PVA concentration, temperature and ionic strength on adsorption capacity. Langmuir constants and Gibbs free energy change (⊿G° were calculated according to experimental data respectively. Thermodynamic analysis indicates the equilibrium adsorbance of PVA on EG increase with the rise of SO42– concentration. Adsorption isotherms of PVA with different degree of polymerization are all types and we deduce PVA molecules lie flat on EG surface. Adsorption processes are all spontaneous. Kinetic studies show that the kinetic data can be described by pseudo second-order kinetic model. Second-order rate constants and the initial adsorption rate rise with the increasing of temperature and half-adsorption time decreases with the increasing of temperature. The adsorption activation energy of each PVA is less than 20 kJ•mol−1, physical adsorption is the major mode of the overall adsorption process.

  11. Expanded BPA residential weatherization program: summary of regional health effects

    International Nuclear Information System (INIS)

    Sandusky, W.F.; Thor, P.W.; Alton, C.C.; Mellinger, P.J.; Cross, F.T.

    1984-11-01

    The Final Environmental Impact Statement (FEIS) for the Bonneville Power Administration (BPA) Expanded Residential Weatherization Program has been completed, printed, and distributed. This document incorporates numerous revisions based on both oral and written comments received during the public comment of the Draft Environmental Impact Statement (DEIS). The estimates of regional health effects were revised to incorporate results of the second Pacific Northwest Residential Energy Survey (PNWRES). The FEIS now expresses the estimated regional health effects in terms of incidence of cancers per 100,000 people exposed, which allows comparison to be made to the annual average risk of fatality by other causes. The estimates of regional health effects are also compared to health effects resulting from supplying and operating a conventional coal plant at a power level equal to the amount of energy saved from installation of additional tightening measures. Numerical results for the estimated health effects described above are provided. A summary of the comments received on the DEIS is also provided, along with estimated health effects associated with the Environmentally Preferred and BPA Preferred Alternatives to the Proposed Action. 8 refs., 3 figs., 5 tabs

  12. Bounded authority: Expanding "appropriate" police behavior beyond procedural justice.

    Science.gov (United States)

    Trinkner, Rick; Jackson, Jonathan; Tyler, Tom R

    2018-06-01

    This paper expands previous conceptualizations of appropriate police behavior beyond procedural justice. The focus of the current study is on the notion of bounded authority-that is, acting within the limits of one's rightful authority. According to work on legal socialization, U.S. citizens come to acquire three dimensions of values that determine how authorities ought to behave: (a) neutral, consistent, and transparent decision-making; (b) interpersonal treatment that conveys respect, dignity, and concern; and (c) respecting the limits of one's rightful power. Using survey data from a nationally representative sample of U.S. adults, we show that concerns over bounded authority, respectful treatment, and neutral decision-making combine to form a strong predictor of police and legal legitimacy. We also find that legal legitimacy is associated with greater compliance behavior, controlling for personal morality and perceived likelihood of sanctions. We discuss the implications of a boundary perspective with respect to ongoing debates over the appropriate scope of police power and the utility of concentrated police activities. We also highlight the need for further research specifically focused on the psychological mechanisms underlying the formation of boundaries and why they shape the legitimacy of the police and law. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  13. Expanded flux variability analysis on metabolic network of Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    CHEN Tong; XIE ZhengWei; OUYANG Qi

    2009-01-01

    Flux balance analysis,based on the mass conservation law in a cellular organism,has been extensively employed to study the interplay between structures and functions of cellular metabolic networks.Consequently,the phenotypes of the metabolism can be well elucidated.In this paper,we introduce the Expanded Flux Variability Analysis (EFVA) to characterize the intrinsic nature of metabolic reactions,such as flexibility,modularity and essentiality,by exploring the trend of the range,the maximum and the minimum flux of reactions.We took the metabolic network of Escherichia coli as an example and analyzed the variability of reaction fluxes under different growth rate constraints.The average variability of all reactions decreases dramatically when the growth rate increases.Consider the noise effect on the metabolic system,we thus argue that the microorganism may practically grow under a suboptimal state.Besides,under the EFVA framework,the reactions are easily to be grouped into catabolic and anabolic groups.And the anabolic groups can be further assigned to specific biomass constitute.We also discovered the growth rate dependent essentiality of reactions.

  14. Expanding the phenome and variome of skeletal dysplasia.

    Science.gov (United States)

    Maddirevula, Sateesh; Alsahli, Saud; Alhabeeb, Lamees; Patel, Nisha; Alzahrani, Fatema; Shamseldin, Hanan E; Anazi, Shams; Ewida, Nour; Alsaif, Hessa S; Mohamed, Jawahir Y; Alazami, Anas M; Ibrahim, Niema; Abdulwahab, Firdous; Hashem, Mais; Abouelhoda, Mohamed; Monies, Dorota; Al Tassan, Nada; Alshammari, Muneera; Alsagheir, Afaf; Seidahmed, Mohammed Zain; Sogati, Samira; Aglan, Mona S; Hamad, Muddathir H; Salih, Mustafa A; Hamed, Ahlam A; Alhashmi, Nadia; Nabil, Amira; Alfadli, Fatima; Abdel-Salam, Ghada M H; Alkuraya, Hisham; Peitee, Winnie Ong; Keng, W T; Qasem, Abdullah; Mushiba, Aziza M; Zaki, Maha S; Fassad, Mahmoud R; Alfadhel, Majid; Alexander, Saji; Sabr, Yasser; Temtamy, Samia; Ekbote, Alka V; Ismail, Samira; Hosny, Gamal Ahmed; Otaify, Ghada A; Amr, Khalda; Al Tala, Saeed; Khan, Arif O; Rizk, Tamer; Alaqeel, Aida; Alsiddiky, Abdulmonem; Singh, Ankur; Kapoor, Seema; Alhashem, Amal; Faqeih, Eissa; Shaheen, Ranad; Alkuraya, Fowzan S

    2018-04-05

    PurposeTo describe our experience with a large cohort (411 patients from 288 families) of various forms of skeletal dysplasia who were molecularly characterized.MethodsDetailed phenotyping and next-generation sequencing (panel and exome).ResultsOur analysis revealed 224 pathogenic/likely pathogenic variants (54 (24%) of which are novel) in 123 genes with established or tentative links to skeletal dysplasia. In addition, we propose 5 genes as candidate disease genes with suggestive biological links (WNT3A, SUCO, RIN1, DIP2C, and PAN2). Phenotypically, we note that our cohort spans 36 established phenotypic categories by the International Skeletal Dysplasia Nosology, as well as 18 novel skeletal dysplasia phenotypes that could not be classified under these categories, e.g., the novel C3orf17-related skeletal dysplasia. We also describe novel phenotypic aspects of well-known disease genes, e.g., PGAP3-related Toriello-Carey syndrome-like phenotype. We note a strong founder effect for many genes in our cohort, which allowed us to calculate a minimum disease burden for the autosomal recessive forms of skeletal dysplasia in our population (7.16E-04), which is much higher than the global average.ConclusionBy expanding the phenotypic, allelic, and locus heterogeneity of skeletal dysplasia in humans, we hope our study will improve the diagnostic rate of patients with these conditions.GENETICS in MEDICINE advance online publication, 5 April 2018; doi:10.1038/gim.2018.50.

  15. Expanding plasmas from anti de Sitter black holes

    International Nuclear Information System (INIS)

    Camilo, Giancarlo

    2016-01-01

    We introduce a new foliation of AdS_5 black holes such that the conformal boundary takes the form of a 4-dimensional FLRW spacetime with scale factor a(t). The foliation employs Eddington-Finkelstein-like coordinates and is applicable to a large class of AdS black holes, supported by matter fields or not, considerably extending previous efforts in the literature. We argue that the holographic dual picture of a CFT plasma on a FLRW background provides an interesting prototype to study the nonequilibrium dynamics of expanding plasmas and use holographic renormalization to extract the renormalized energy-momentum tensor of the dual plasma. We illustrate the procedure for three black holes of interest, namely AdS-Schwarzschild, AdS-Gauss-Bonnet, and AdS-Reissner-Nordstroem. For the latter, as a by-product, we show that the nonequilibrium dynamics of a CFT plasma subject to a quench in the chemical potential (i.e., a time-dependent chemical potential) resembles a cosmological evolution with the scale factor a(t) being inversely related to the quench profile μ(t). (orig.)

  16. Initiation of a boiling liquid expanding vapour explosion

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, C.A.

    1990-01-01

    Boiling liquid expanding vapour explosions (BLEVEs) occur when a pressure liquefied gas tank is burst and the fluid is ejected to the atmosphere. As the liquid is exposed to a lower pressure it boils violently, causing an explosion which destroys the container. One litre tanks were filled with propane or R12, heated, and caused to rupture at specific test conditions to determine the parameters required for a BLEVE. Results showed that the energy stored in the liquid under pressure relative to the liquid at atmospheric conditions was a quantity which can be used to predict a BLEVE for the particular apparatus and conditions used. The possible importance of the development of a shock wave within the container during a BLEVE was noted. A shock tube was used to study the shock waves generated during a BLEVE. Temperature, liquid volume, rupture location, rupture area, and the fluid involved were varied. The pressure was measured vs time for periods immediately after the rupture. Photographs of the formation of pressure waves were obtained using spark Schlieren photography. Similarities to waves measured during detonations in ducts were noted. Pressure information was also gathered during BLEVEs of one litre cylinders, and this data is compared to that from the shock tube. Shock tube data showed that transverse waves formed from the initial pressure wave could be amplified. 37 refs., 54 figs., 11 tabs.

  17. Expanding Access with Satellite-Enabled Distance Education

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2006-12-01

    Full Text Available Education and training became increasingly critical for citizens of every nation during the last century, and that paradigm will be no less true, throughout the 21st Century. As the world progresses fully into an information society, access to information and to a knowledge-based work force is a precondition for any country to remain competitive. Education, and increasingly distant education (DE, plays a vital role in turning human resources into knowledge workers. Information and communications technologies (ICT have provided new ways to educate and to disseminate information that is crucial for creating these competitive, knowledge-based work forces. Modern DE, enabled by ICT-based networks and the Internet tools, offers great advantages that are leveling the global playing field, in terms of providing access and opportunities for specialized training and education. Using satellite technology in DE may be imperative to developing countries, where the majority of their populations are scattered in rural and remote areas. Where the traditional brick and mortar classrooms cannot easily reach, satellite-powered DE systems can. Through literature review and rational analysis, this paper examines how satellite-assisted DE systems expand education access.

  18. India expanding oil/gas E and D, infrastructure

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This paper reports that India continues to press oil and gas exploration and development and expansion of its petroleum sector infrastructure. One of the key moves is the government's decision to stage a fourth exploration bidding round, its most ambitious to date and one expected to elicit enthusiasm from international oil companies. At the same time, state oil companies Oil and Natural Gas Commission and Oil India Ltd. plan to maintain strong domestic E and D programs. ONGC is seeking more revenue to sustain India's ambitious oil and gas upstream plans. The state company has asked the government for a 50% hike in the price of domestic crude. The government currently pays ONGC and OIL only about $8.84/bbl, a price fixed in 1981. A jump of 50% in the domestic crude price would net ONGC another $1 billion/year in revenues, ONGC Chairman S.L. Khosla the. The government and other state companies also continue efforts to expand gas utilization and markets and match refining plans with market needs

  19. Expanding the scope of leadership training in medicine.

    Science.gov (United States)

    Gabel, Stewart

    2014-06-01

    All physicians take a leadership role at some point in their career-some exert influence in their practices and communities as informal leaders, and others hold formal leadership roles to which they are appointed or elected. These formal leadership roles convey power to those individuals who hold such positions. Formal leadership, however, is limited in its influence unless it is accompanied by a series of personal and interpersonal competencies that characterize both formal and informal leaders.Many physicians who do not hold formal leadership roles will be called on to provide (or will wish to provide) informal leadership at various times in their careers. Both formal and informal leaders should be trained in the personal and interpersonal competencies necessary for effective leadership to advance the principles-driven and values-oriented goals inherent in the health care enterprise.In this article, the author defines leadership and describes the characteristics of formal and informal leaders, then discusses the types of leadership and the power derived from different leadership roles. He concludes by arguing in favor of expanding the scope of leadership training to include informal as well as formal leaders.

  20. Expanding the storage capability at ETRR research reactor at Inshas

    International Nuclear Information System (INIS)

    Mariy, A.; Sultan, M.; Khattab, M.

    2000-01-01

    Storing of spent fuel from test reactor in developing countries has become a big dilemma for the following reasons: The transportation of spent fuel is very expensive. There is no reprocessing plants in most developing countries. The expanding of existing storage facilities in reactor building require experience that most of developing countries lack. some political motivations from nuclear developed countries intervene which makes the transportation procedures and logistics to those countries difficult. This paper gives the conceptual design of a new spent fuel storage now under construction at Inshas research reactor (ETRR-1). The location of the new storage facility is chosen to be within the premises of the reactor facility so that both reactor and the new storage are one material balance area. The paper also proposes some ideas that can enhance the transportation and storage of spent fuel of test reactors, such as: Intensifying the role of IAEA in helping countries to get rid of the spent fuel. The initiation of regional spent fuel storage facilities in some developing countries