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Sample records for nonmotile irregular coccoid

  1. Methanoculleus palmolei sp. nov., an irregularly coccoid methanogen from an anaerobic digester treating wastewater of a palm oil plant in north-Sumatra, Indonesia.

    Science.gov (United States)

    Zellner, G; Messner, P; Winter, J; Stackebrandt, E

    1998-10-01

    Strain INSLUZT (= DSM 4273T) was isolated from a biogas-producing bioreactor treating wastewater of a palm oil mill on North-Sumatra (Indonesia). Cells of strain INSLUZT were highly irregularly coccoid, 1.25-2.0 microns in diameter, had a cell envelope consisting of the cytoplasmic membrane and an S-layer of hexagonally arranged glycoprotein subunits with an M(r) of 120,000, and were flagellated (motility was not observed). Cells were mesophilic and grew most rapidly at 40 degrees C on H2/CO2' formate, 2-propanol/CO2 2-butanol/CO2 and cyclopentanol/CO2 to give methane. Tungstate promoted growth on H2/CO2 with acetate as the solely required organic medium supplement. The G + C content of DNA was 59 mol% (Tm method) and 59.5 mol% (HPLC method). 16S rDNA analysis revealed a phylogenetic relationship to Methanoculleus species; the name Methanoculleus palmolei sp. nov. is therefore proposed for strain INSLUZT (= DSM 4273T).

  2. Agglutination of Mouse Erythrocytes by Eperythrozoon coccoides

    OpenAIRE

    Iralu, Vichazelhu; Ganong, Kevin D.

    1983-01-01

    Erythrocytes from blood of mice infected with Eperythrozoon coccoides for 3 or 4 days agglutinated spontaneously. Washed E. coccoides particles agglutinated washed erythrocytes of uninfected mice. E. coccoides-mediated agglutination of normal mouse erythrocytes would be an excellent system for studies of bacterial adhesion.

  3. Agglutination of Mouse Erythrocytes by Eperythrozoon coccoides

    Science.gov (United States)

    Iralu, Vichazelhu; Ganong, Kevin D.

    1983-01-01

    Erythrocytes from blood of mice infected with Eperythrozoon coccoides for 3 or 4 days agglutinated spontaneously. Washed E. coccoides particles agglutinated washed erythrocytes of uninfected mice. E. coccoides-mediated agglutination of normal mouse erythrocytes would be an excellent system for studies of bacterial adhesion. Images PMID:6832825

  4. Agglutination of Mouse Erythrocytes by Eperythrozoon coccoides

    OpenAIRE

    Iralu, Vichazelhu; Ganong, Kevin D.

    1983-01-01

    Erythrocytes from blood of mice infected with Eperythrozoon coccoides for 3 or 4 days agglutinated spontaneously. Washed E. coccoides particles agglutinated washed erythrocytes of uninfected mice. E. coccoides-mediated agglutination of normal mouse erythrocytes would be an excellent system for studies of bacterial adhesion.

  5. Complete genome sequence of the termite hindgut bacterium Spirochaeta coccoides type strain (SPN1 T ), reclassification in the genus Sphaerochaeta as Sphaerochaeta coccoides comb. nov. and emendations of the family Spirochaetaceae and the genus Sphaerochaeta

    Energy Technology Data Exchange (ETDEWEB)

    Abt, Birte [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Han, Cliff [Los Alamos National Laboratory (LANL); Scheuner, Carmen [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Lu, Megan [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Hammon, Nancy [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Gronow, Sabine [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute

    2012-01-01

    Spirochaeta coccoides Droege et al. 2006 is a member of the genus Spirochaeta Ehrenberg 1835, one of the oldest named genera within the Bacteria. S. coccoides is an obligately anaerobic, Gram-negative, non-motile, spherical bacterium that was isolated from the hindgut contents of the termite Neotermes castaneus. The species is of interest because it may play an important role in the digestion of breakdown products from cellulose and hemicellulose in the termite gut. Here we provide a taxonomic re-evaluation for strain SPN1{sup T}, and based on physiological and genomic characteristics, we propose its reclassification as a novel species in the genus Sphaerochaeta, a recently published sister group of the Spirochaeta. The 2,227,296 bp long genome of strain SPN1{sup T} with its 1,866 protein-coding and 58 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  6. Complete genome sequence of the termite hindgut bacterium Spirochaeta coccoides type strain (SPN1T), reclassification in the genus Sphaerochaeta as Sphaerochaeta coccoides comb. nov. and emendations of the family Spirochaetaceae and the genus Sphaerochaeta

    Energy Technology Data Exchange (ETDEWEB)

    Abt, Birte; Han, Cliff; Scheuner, Carmen; Lu, Megan; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxane; Goodwin, Lynne; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mavromatis, Konstantinos; Mikhailova, Natalia; Huntemann, Marcel; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Gronow, Sabine; Goker, Markus; Woyke, Tanja; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter; Detter, John C.

    2012-05-25

    Spirochaeta coccoides Dröge et al. 2006 is a member of the genus Spirochaeta Ehrenberg 1835, one of the oldest named genera within the Bacteria. S. coccoides is an obligately anaerobic, Gram-negative, non-motile, spherical bacterium that was isolated from the hindgut contents of the termite Neotermes castaneus. The species is of interest because it may play an important role in the digestion of breakdown products from cellulose and hemicellulose in the termite gut. Here we provide a taxonomic re-evaluation for strain SPN1T, and based on physiological and genomic characteristics, we propose its reclassification as a novel species in the genus Sphaerochaeta, a recently published sister group of the Spirochaeta. The 2,227,296 bp long genome of strain SPN1T with its 1,866 protein-coding and 58 RNA genes is a part of the GenomicEncyclopedia of Bacteria and Archaea project.

  7. Agglutination of Helicobacter pylori coccoids by lectins

    Institute of Scientific and Technical Information of China (English)

    Mar Mar Khin; Jie Song Hua; Hah Cong Ng; Bow Ho; Torkel Wadstrorr

    2000-01-01

    AIM To study the agglutination pattern of Helicobacter pylori coccoid and spiral forms.METHODS Assays of agglutination and agglutination inhibition were applied using fifteen commercial lectins. RESULTS Strong agglutination was observed with mannose-specific Concanavalin A (Con A ),fucose-specific Tetragonolobus purpureas ( Lotus A ) and N-acetyl glucosamine-specific Triticum vulgaris (WGA) lectins. Mannose and fucose specific lectins were reactive with all strains of H. pylori coccoids as compared to the spirals. Specific carbohydrates, glycoproteins and mucin were shown to inhibit H. pylori lectin-agglutination reactions. Pre-treatment of the bacterial cells with formalin and sulphuric acid did not alter the agglutination patterns with lectins. However, sodium periodate treatment of bacterial cells were shown to inhibit agglutination reaction with Con A, Lotus A and WGA lectins. On the contrary, enzymatic treatment of coccoids and spirals did not show marked inhibition of H. pylori-lectin agglutination. Interestingly, heating of H.pylori cells at 60℃ for 1 hour was shown to augment the agglutination with all of the lectins tested. CONCLUSION The considerable differences in lectin agglutination patterns seen among the two differentiated forms of H. pylori might be attributable to the structural changes during theevents of morphological transformation,resulting in exposing or masking some of the sugar residues on the cell surface. Possibility of various sugar residues on the cell wall of the coccoids may allow them to bind to different carbohydrate receptors on gastric mucus and epithelial cells. The coccoids with adherence characteristics like the spirals could aid in the pathogenic process of Helicobacter infection.This may probably lead to different clinical outcome of H. pylori associated gastroduodenal disease.

  8. Methods for detecting the environmental coccoid form of Helicobacter pylori

    Directory of Open Access Journals (Sweden)

    Mahnaz eMazaheri Assadi

    2015-05-01

    Full Text Available Helicobacter pylori is recognized as the most common pathogen to cause gastritis, peptic and duodenal ulcers, and gastric cancer. The organisms are found in two forms: 1 spiral-shaped bacillus and 2 coccoid. H. pylori coccoid form, generally found in the environment, is the transformed form of the normal spiral-shaped bacillus after exposed to water or adverse environmental conditions such as exposure to sub-inhibitory concentrations of antimicrobial agents. The putative infectious capability and the viability of H. pylori under environmental conditions are controversial. This disagreement is partially due to the fact of lack in detecting the coccoid form of H. pylori in the environment. Accurate and effective detection methods of H. pylori will lead to rapid treatment and disinfection, and less human health damages and reduction in health care costs. In this review, we provide a brief introduction to H. pylori environmental coccoid forms, their transmission and detection methods. We further discuss the use of these detection methods including their accuracy and efficiency.

  9. Indirect benefits of symbiotic coccoids for an ant-defended myrmecophytic tree.

    Science.gov (United States)

    Pringle, Elizabeth G; Dirzo, Rodolfo; Gordon, Deborah M

    2011-01-01

    The net benefits of mutualism depend directly on the costs and effectiveness of mutualistic services and indirectly on the interactions that affect those services. We examined interactions among Cordia alliodora myrmecophytic trees, their symbiotic ants Azteca pittieri, coccoid hemipterans, and foliar herbivores in two Neotropical dry forests. The tree makes two investments in symbiotic ants: it supplies nesting space, as domatia, and it provides phloem to coccoids, which then produce honeydew that is consumed by ants. Although higher densities of coccoids should have higher direct costs for trees, we asked whether higher densities of coccoids can also have higher indirect benefits for trees by increasing the effectiveness of ant defense against foliar herbivores. We found that trees benefited from ant defense against herbivores. Ants defended trees effectively only when colonies reached high densities within trees, and ant and coccoid densities within trees were strongly positively correlated. The benefits of reduced foliar herbivory by larger ant colonies were therefore indirectly controlled by the number of coccoids. Coccoid honeydew supply also affected per capita ant aggression against tree herbivores. Ants experimentally fed a carbohydrate-rich diet, analogous to sugar obtained from coccoids, were more aggressive against caterpillars per capita than ants fed a carbohydrate-poor diet. Ant defense was more effective on more valuable and vulnerable young leaves than on older leaves. Young domatia, associated with young leaves, contained higher coccoid densities than older domatia, which suggests that coccoids may also drive spatially favorable ant defense of the tree. If higher investments by one mutualistic partner are tied to higher benefits received from the other, there may be positive feedback between partners that will stabilize the mutualism. These results suggest that higher investment by trees in coccoids leads to more effective defense by ants against

  10. Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form

    Institute of Scientific and Technical Information of China (English)

    Ke-Xia Wang; Xue-Feng Wang

    2004-01-01

    AIM: To clone and sequence the cagA gene fragment of Helicobacter pylori ( H pylori) with coccoid form.METHODS: H pylori strain NCTC11637 were transformed to coccoid form by exposure to antibiotics in subinhibitory concentrations. The coccoid H pyloriwas collected. cagA gene of the coccoid H pylori strain was amplified by PCR.After purified, the target fragment was cloned into plasmid pMD-18T. The recombinant plasmid pMD-18T-cagA was transformed into E. coli JM109. Positive clones were screened and identified by PCR and digestion with restriction endonucleases. The sequence of inserted fragment was then analysed.RESULTS: cagA gene of 3 444 bp was obtained from the coccoid H pylori genome DNA. The recombinant plasmid pMD-18T-cagA was constructed, then it was digested by BamH Ⅰ+Sac Ⅰ, and the product of digestion was identical with the predicted one. Sequence analysis showed that the homology of coccoid and the reported original sequence H pylori was 99.7%.CONCLUSION: The recombinant plasmid containing cagA gene from coccoid H pylori has been constructed successfully.The coccoid H pylori contain completed cagA gene, which may be related to pathogenicity of them.

  11. Irregular Periods

    Science.gov (United States)

    ... blood become too low or too high. Some women have irregular periods because their bodies produce too much androgen, which is a hormone that causes increased muscle mass, facial hair, and deepening of the voice in males and ...

  12. Coccoid Form of Helicobacter pylori as a Morphological Manifestation of Cell Adaptation to the Environment▿ †

    Science.gov (United States)

    Azevedo, N. F.; Almeida, C.; Cerqueira, L.; Dias, S.; Keevil, C. W.; Vieira, M. J.

    2007-01-01

    After characterization of preferred conditions for Helicobacter pylori survival in the sessile state, it was observed that the bacterium transforms from spiral to coccoid under mild circumstances, whereas under extreme ones it is unable to undergo shape modification. This strongly supports the view that transformation into the coccoid form is an active, biologically led process, switched on by the bacterium as a protection mechanism. PMID:17400788

  13. Perceiving the algae: How feeding-current feeding copepods detect their nonmotile prey

    DEFF Research Database (Denmark)

    Goncalves, Rodrigo J.; Kiørboe, Thomas

    2015-01-01

    Feeding-current feeding copepods detect and capture prey individually, but the mechanism by which nonmotile prey is detected has been unclear. Early reports that copepods detect phytoplankton prey at distances of one body length or more led to the hypothesis that solutes leaking from the prey wou...

  14. Virulence and potential pathogenicity of coccoid Helicobacter pylori induced by antibiotics

    Science.gov (United States)

    She, Fei-Fei; Su, Dong-Hui; Lin, Jian-Yin; Zhou, Lin-Ying

    2001-01-01

    AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole. Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep 2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot. The mutation of the genes including ureA, ureB, hpaA, vacA and cagA, related with virulence, was detected by means of PCR and PCR-SSCP. RESULTS: In the coccoid H. pylori, the urease activity, the adherence to Hep 2 cells and the vacuolating cytotoxicity to Hela cells alldecreased. In strain F44, the rate and index of adherence reduced from 70.0% ± 5.3% to 33% ± 5.1% and from 2.6 ± 0.4 to 0.96 ± 0.3 (P hpaA or vacA. CONCLUSION: The virulence and the proteins with molecular weight over Mr 74000 in coccoid H.pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA, vacA and cagA genes, suggesting that coccoid H.pylori may have potential pathogenicity. PMID:11819770

  15. Irregular amalgams

    Directory of Open Access Journals (Sweden)

    James Stewart

    1986-01-01

    Full Text Available The amalgam of Lp and ℓq consists of those functions for which the sequence of Lp-norms over the intervals [n,n+1 is in ℓq. These spaces (Lp,ℓq have been studied in several recent papers. Here we replace the intervals [n,n+1 by a cover α={In;n∈Z} of the real line consisting of disjoint half-open intervals In each of the form [a,b, and investigate which properties of (Lp,ℓq carry over to these irregular amalgams (Lp,ℓqα. In particular, we study how (Lp,ℓqα varies as p, q, and α vary and determine conditions under which translation is continuous.

  16. Expression and Characterization of Flagella in Nonmotile Enteroinvasive Escherichia coli Isolated from Diarrhea Cases

    OpenAIRE

    Andrade,Agda; Jorge A Girón; Amhaz, Juliana M. K.; Trabulsi, Luiz R.; Marina B Martinez

    2002-01-01

    We report that enteroinvasive Escherichia coli (EIEC) serotypes considered to be nonmotile produce an unusually large (77 kDa) flagellin that is assembled into functional flagellum filaments that allow the bacteria to swim in modified motility agar. The EIEC flagellin showed N-terminal identity to most common enterobacterial flagellins, especially those of the E. coli H7 serotype. These data are important in terms of the epidemiology, evolution, and biology of EIEC.

  17. Chloropyrula uraliensis gen.et sp.nov.(Trebouxiophyceae,Chlorophyta), a new green coccoid alga with a unique ultrastructure, isolated from soil in South Urals

    Institute of Scientific and Technical Information of China (English)

    Lira GAYSINA; Yvonne N(E)MCOV(A); Pavel (S)KALOUD; Tereza (S)EV(CI)KOV(A); Marek ELI(AS)

    2013-01-01

    Soil hosts diverse communities of photosynthetic eukaryotes (algae) that have not yet been fully explored.Here we describe an interesting coccoid green alga isolated from a soil sample from a forest-steppe in South Urals (Bashkortostan,Russia) that,based on a phylogenetic analysis of 18S rRNA gene sequence,appears to represent a new phylogenetic lineage related to the genus Leptosira within the class Trebouxiophyceae.This new alga is characterized by uninucleate cells with a shape ranging from spherical to ellipsoid or egg-like,occurring solitary or more often grouped in irregular masses or colonies.Remarkably,cells with a characteristic pyriform shape are encountered in cultures grown on a solid medium.The cells harbour a single pyrenoid-lacking parietal chloroplast with the margin undulated or forming finger-like projections; in mature cells the chloroplast becomes divided by deep incisions into more or less separate lobes.Transmission electron microscopy of vegetative cells revealed an unprecedented structure in the form of a cluster of microfibrils located in the cytoplasm near the plasma membrane,often appressed to the chloroplast.Reproduction takes place via autospores or biflagellated zoospores.The unique suite of characters of our isolate distinguishes it from previously described coccoid green algae and suggests that it should be classified as a new species in a new genus; we propose it be named Chloropyrula uraliensis.

  18. Sex pheromone of a coccoid insect with sexual and asexual lineages: fate of an ancestrally essential sexual signal in parthenogenetic females.

    Science.gov (United States)

    Tabata, Jun; Ichiki, Ryoko T; Moromizato, Chie; Mori, Kenji

    2017-03-01

    Sex pheromones play a central role in intersexual communication for reproduction in many organisms. Particularly in insects, reproductive isolation that leads to speciation is often achieved by shifts of pheromone chemistries. However, the divergence and evolution of pheromones remain largely unknown. This study reveals a unique evolutionary consequence for terpenoid pheromones in coccoid insects. Coccoids, such as mealybugs, show clear sexual dimorphism: males are dwarf and short-lived, whereas females are wingless and almost immobile. Female pheromones are therefore indispensable for males to navigate for sexual reproduction, but some females can reproduce asexually. Interestingly, a derived asexual lineage that reproduces by parthenogenesis coexists with its ancestral lineage that reproduces sexually in a population of the pineapple mealybug, Dysmicoccus brevipes Here, we isolated, characterized and synthesized a novel monoterpene, (-)-(anti-1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde, as a pheromone of the sexual females of Dbrevipes This monoterpene aldehyde, with an irregular linkage of isoprene units, is notable, because all mealybug pheromones previously reported are carboxylic esters of terpenols. This compound was, however, never produced by the asexual females. As a consequence of acquiring parthenogenetic reproduction, the asexual females appear to have abandoned the production of the sex pheromone, which had been essential to attracting males in their ancestors.

  19. Virulence and potential pathogenicity of coccoid Helicobacter pylori induced by antibiotics

    Institute of Scientific and Technical Information of China (English)

    Fei Fei She; Dong Hui Su; Jian Yin Lin; Lin Ying Zhou

    2001-01-01

    AIM To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic.METHODS Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole.Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot,The mutation of the genes including ureA, ureB,hpaA; vacA and cagA, related with virulence,was detected by means of PCR and PCR-SSCP.RESULTS In the coccoid H. pylori, the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells alldecreased. In strain F44, the rate and index of adherence reduced from 70.0% ± 5.3% to 33% ±5.1% and from 2.6 ±0.4 to 0.96 ±0.3 (P<0.01),respectively. The invasion of coccoid H. pylori into Hep-2 cell could be seen under electronmicroscope. SDS-PAGE showed that the content of the protein with the molecular weight over Mr74 000 decreased, and the hybriditional signal in band Mr 125 000 weakened, while the band Mr 110000 and Mr63000 strengthened in coccoid H. pylori as shown in Western blot. The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA.CONCLUSION The virulence and the proteins with molecular weight over Mr74 000 in coccoid H. pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA,vacA and cagA genes, suggesting that coccoid H. pylori may have potential pathogenicity.

  20. Virulence of water-induced coccoid Helicobacter pylori and its experimental infection in mice

    Institute of Scientific and Technical Information of China (English)

    Fei-Fei She; Jian-Yin Lin; Jun-Yan Liu; Cheng Huang; Dong-Hui Su

    2003-01-01

    AIM: To explore the virulence and the infectivity of coccoid Helicobacter ppylori(H.pylori) transformed from spiral form by exposure to sterile tap water.METHODS: Three strains of H.pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid form by exposure to sterile tap water.Both spiral and coccoid forms of H.pylori were tested for the urease activity, and the adherence to Hep-2 cells. The presence of flagella was examined under electron microscopy. In the experimental animal infection, the spiral and coccoid forms of H.pylori originated from the same strain F49 were inoculated intragastrically into BALB/c mice respectively four times at a 3-day interval. Half of the mice from each group were sacrificed at Day 21 and Day 28 after the last inoculation. Histology and H.pylori colonization were detected by urease test of gastric mucosa, cultures of H. pylori,and electron microscopy and so on.RESULTS: The urease activity and the ability of adherence to Hep-2 cells were found to be lower in coccoid H.pylori than that in its spiral form. For example, the transformation in strain F44 led to a significant decrease of the adherence rate and adherence index from 70.0±5.3 % to 30.2±3.5 %(P<0.01), and from 2.6±0.4 to 0.86±0.3 (P<0.01),respectively. The flagella of coccoid H.pylori were observed under electron microscope. In the experimental infection in mice, the positive rate of gastric mucosa urease test was 93.8 % (15/16) in the group infected by spiral H.pylori and 50 % (8/16) in the group infected by coccoid H. pylori,and the estimated coccoid H.pylori colony number was 1.75 vs0,56. The positive rates of H. pyloriculture were 87.5 %(14/16) in spiral H. pylori group and 68.8 % (11/16) in coccoid H.pylorigroup. There was no significant difference in either urease test or bacterial culture rate between the groups examined at Day 21 and Day 28 after inoculation. Electron microscopic examination of the samples

  1. Diversity and geographic distribution of desmids and other coccoid green algae

    NARCIS (Netherlands)

    Coesel, P.F.M.; Krienitz, L.

    2008-01-01

    Taxonomic diversity of desmids and other coccoid green algae is discussed in relation to different species concepts. For want of unambiguous criteria about species delimitation, no reliable estimations of global species richness can be given. Application of the biological species concept is seriousl

  2. Three novel species of coccoid green algae within the Watanabea clade (Trebouxiophyceae, Chlorophyta).

    Science.gov (United States)

    Song, Huiyin; Hu, Yuxin; Zhu, Huan; Wang, Qinghua; Liu, Guoxiang; Hu, Zhengyu

    2016-12-01

    Coccoid green algae are extremely diverse despite their simple coccoid phenotype, a phenotype that may be the result of convergent evolution. In this study, we used a polyphasic approach combining molecular phylogenetic analyses, morphology and ultrastructure to investigate isolated coccoid strains from China, and our results reveal three new lineages of Trebouxiophyceae: the novel genus and species Mysteriochloris nanningensis gen. et sp. nov., and the two novel species Phyllosiphon coccidium sp. nov. and Desertella yichangensis sp. nov. (Trebouxiophyceae, Chlorophyta). We provide a detailed characterization of the novel microalgae which they are autosporic coccoid unicells and have parietal chloroplasts. In phylogenies based on 18S rDNA sequences and the chloroplast ribulose-bisphosphate carboxylase gene (rbcL), these three algae are nested within the Watanabea clade and are different from any known algae. M. nanningensis FACHB-1787 is not really close to any known algae within the Watanabea clade. Phyllosiphoncoccidium FACHB-2212 is within the Phyllosiphon lineages. D. yichangensis FACHB-1793 is closely related to Desertella californica and described as a representative of a novel species of the genus Desertella.

  3. A kind of coccoid dinoflagel-lates-like fossils gives a new explanation of source of dinosterane in the Early- Middle Cambrian

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The coccoid fossils covered with thick gelatinous envelop containing several gametes are discovered in gyps and salt deposits of Cambrian, H4 well and chert bed of the base of Yuertus Formation (∈11) of Xiaoerbulake Section. The fossils are described and compared with coccoid dino-flagellates. These fossils may be a coccoid life-cycle stage (vegetative cyst) of coccoid dinoflagellates. If this identifica-tion is correct, the coccoid dinoflagellates-like fossils could give a reasonable explanation of the dinoflagellate-specific biomarkers from Cambrian, H4 well, Tarim Basin.

  4. What Causes Menstrual Irregularities?

    Science.gov (United States)

    ... Publications What causes menstrual irregularities? Skip sharing on social media links Share this: Page Content Menstrual irregularities can be caused by a variety of conditions, including pregnancy, hormonal imbalances, infections, malignancies, diseases, trauma, and certain ...

  5. ATPase Cycle of the Nonmotile Kinesin NOD Allows Microtubule End Tracking and Drives Chromosome Movement

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, J.; Sindelar, C; Mulko, N; Collins, K; Kong, S; Hawley, R; Kull, F

    2009-01-01

    Segregation of nonexchange chromosomes during Drosophila melanogaster meiosis requires the proper function of NOD, a nonmotile kinesin-10. We have determined the X-ray crystal structure of the NOD catalytic domain in the ADP- and AMPPNP-bound states. These structures reveal an alternate conformation of the microtubule binding region as well as a nucleotide-sensitive relay of hydrogen bonds at the active site. Additionally, a cryo-electron microscopy reconstruction of the nucleotide-free microtubule-NOD complex shows an atypical binding orientation. Thermodynamic studies show that NOD binds tightly to microtubules in the nucleotide-free state, yet other nucleotide states, including AMPPNP, are weakened. Our pre-steady-state kinetic analysis demonstrates that NOD interaction with microtubules occurs slowly with weak activation of ADP product release. Upon rapid substrate binding, NOD detaches from the microtubule prior to the rate-limiting step of ATP hydrolysis, which is also atypical for a kinesin. We propose a model for NOD's microtubule plus-end tracking that drives chromosome movement.

  6. Predictive value of hypo-osmotic swelling test to identify viable non-motile sperm

    Institute of Scientific and Technical Information of China (English)

    WilliamM.Bucker

    2003-01-01

    Aim: To determine the predictive value of the hypo-osmotic swelling (HOS) test to identify viable, non-motile sperm. Methods: Semen samples from 20 men with severe asthenozoospermia underwent traditional seminal analysis, eosin-nigrosin (EN) staining and the HOS test. A further EN stain was then pexformed on a HOS pre-treated aliquot and a total of 2000 further sperm examined. Results: The median sperm density was 5.1 million/mL (IQR 4.3-13.1) and the median motility was 3.0 % (IQR 0-7). Seven samples showed complete asthenozoospermia. Initial EN staining showed 59 % viability (range 48-69) despite the poor standard parameters and 47 % (range 33-61) in thecomplete asthenozoospermia subgroup. The HOS test showed 49.9 % reacted overall (range 40-59) and 41.7 %(range 22-61) in the complete asthenozoospermia subgroup. The combined HOSfEN stain showed the positive pre-dictive value of the HOS test to identify viable sperm was 84.2 % overall and 79.7 % in the complete asthenozoospermia subgroup. Conclusion: The HOS test can effectively predict sperm viability in patients with severe and complete asthenozoospermia. ( Asian J Andro12003 Sep; 5: 209-212)

  7. Streptococcus mitis induces conversion of Helicobacter pylori to coccoid cells during co-culture in vitro.

    Directory of Open Access Journals (Sweden)

    Yalda Khosravi

    Full Text Available Helicobacter pylori (H. pylori is a major gastric pathogen that has been associated with humans for more than 60,000 years. H. pylori causes different gastric diseases including dyspepsia, ulcers and gastric cancers. Disease development depends on several factors including the infecting H. pylori strain, environmental and host factors. Another factor that might influence H. pylori colonization and diseases is the gastric microbiota that was overlooked for long because of the belief that human stomach was a hostile environment that cannot support microbial life. Once established, H. pylori mainly resides in the gastric mucosa and interacts with the resident bacteria. How these interactions impact on H. pylori-caused diseases has been poorly studied in human. In this study, we analyzed the interactions between H. pylori and two bacteria, Streptococcus mitis and Lactobacillus fermentum that are present in the stomach of both healthy and gastric disease human patients. We have found that S. mitis produced and released one or more diffusible factors that induce growth inhibition and coccoid conversion of H. pylori cells. In contrast, both H. pylori and L. fermentum secreted factors that promote survival of S. mitis during the stationary phase of growth. Using a metabolomics approach, we identified compounds that might be responsible for the conversion of H. pylori from spiral to coccoid cells. This study provide evidences that gastric bacteria influences H. pylori physiology and therefore possibly the diseases this bacterium causes.

  8. Assessment of cagE and babA mRNA expression during morphological conversion of Helicobacter pylori from spiral to coccoid.

    Science.gov (United States)

    Poursina, Farkhondeh; Faghri, Jamshid; Moghim, Sharareh; Zarkesh-Esfahani, Hamid; Nasr-Esfahani, Bahram; Fazeli, Hossein; Hasanzadeh, Akbar; Safaei, Hajieh Ghasemian

    2013-04-01

    Helicobacter pylori (H. Pylori) is an actively dividing spiral bacterium that changes to coccoid morphology under stressful environments. The infectivity of the coccoids is still controversial. The aim of this study was to determine the viability and expression of two important virulence genes (babA and cagE), in antibiotic-induced coccoid forms. Three strains of H. pylori, the standard 26695 and two clinical isolates (p1, p2) were converted to coccoid form by amoxicillin. Coccoids were identified according to Gram-staining and microscopic morphology. The viability of the cells was analyzed by flow cytometry. The expression of cagE and babA in coccoid forms were evaluated and compared to the spirals by quantitative PCR assay. The coccoid forms were developed after 72 h exposure of H. pylori to ½ MIC of amoxicillin, and the conversion form was completed (100 %) at 144 h in all of three isolates. Flow cytometry analyses showed that the majority of the induced coccoids (90-99.9 %) were viable. Expression of cagE and babA was seen in coccoids; however, in lower rate (cagE, ~3-fold and babA, ~10-fold) than these in spiral forms. Coccoid forms of two clinical isolates significantly expressed higher rate of cagE and babA than standard 26695 strain (P = 0.01). These results suggest that the induced coccoid form of H. pylori is not a passive entity but can actively infect the human by expression of the virulence genes for long time in stomach and probably play a role in chronic and severe disease.

  9. Star Formation in Irregular Galaxies.

    Science.gov (United States)

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  10. Multivariate irregular sampling theorem

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,we prove a Marcinkiewicz-Zygmund type inequality for multivariate entire functions of exponential type with non-equidistant spaced sampling points. And from this result,we establish a multivariate irregular Whittaker-Kotelnikov-Shannon type sampling theorem.

  11. Multivariate irregular sampling theorem

    Institute of Scientific and Technical Information of China (English)

    CHEN GuangGui; FANG GenSun

    2009-01-01

    In this paper, we prove a Marcinkiewicz-Zygmund type inequality for multivariate entire functions of exponential type with non-equidistant spaced sampling points. And from this result, we establish a multivariate irregular Whittaker-Kotelnikov-Shannon type sampling theorem.

  12. Aliterella atlantica gen. nov., sp. nov., and Aliterella antarctica sp. nov., novel members of coccoid Cyanobacteria.

    Science.gov (United States)

    Rigonato, Janaina; Gama, Watson Arantes; Alvarenga, Danillo Oliveira; Branco, Luis Henrique Zanini; Brandini, Frederico Pereira; Genuário, Diego Bonaldo; Fiore, Marli Fatima

    2016-09-01

    Two Cyanobacteria isolated from South Atlantic Ocean continental shelf deep water and from a marine green algae inhabiting the Admiralty Bay, King George Island, Antarctica were investigated based on morphological and ultrastructural traits, phylogeny of 16S rRNA gene sequences, secondary structure of the 16S-23S internal transcribed spacer regions and phylogenomic analyses. The majority of these evaluations demonstrated that both strains differ from the genera of cyanobacteria with validly published names and, therefore, supported the description of the novel genus as Aliterella gen. nov. The identity and phylogeny of 16S rRNA gene sequences, together with the secondary structure of D1D1' and BoxB intergenic regions, further supported the two strains representing distinct species: Aliterella atlantica gen. nov., sp. nov. (type SP469036, strain CENA595T) and Aliterella antarctica sp. nov. (type SP469035, strain CENA408T). The phylogenomic analysis of A. atlantica sp. nov. CENA595T, based on 21 protein sequences, revealed that this genus belongs to the cyanobacterial order Chroococcidiopsidales. The isolation and cultivation of two geographically distant unicellular members of a novel cyanobacterial genus and the sequenced genome of the type strain bring new insights into the current classification of the coccoid group, and into the reconstruction of their evolutionary history.

  13. Crystal habits and magnetic microstructures of magnetosomes in coccoid magnetotactic bacteria

    Directory of Open Access Journals (Sweden)

    Ulysses Lins

    2006-09-01

    Full Text Available We report on the application of off-axis electron holography and high-resolution TEM to study the crystal habits of magnetosomes and magnetic microstructure in two coccoid morphotypes of magnetotactic bacteria collected from a brackish lagoon at Itaipu, Brazil. Itaipu-1, the larger coccoid organism, contains two separated chains of unusually large magnetosomes; the magnetosome crystals have roughly square projections, lengths up to 250 nm and are slightly elongated along [111] (width/length ratio of about 0.9. Itaipu-3 magnetosome crystals have lengths up to 120 nm, greater elongation along [111] (width/length ~0.6, and prominent corner facets. The results show that Itaipu-1 and Itaipu-3 magnetosome crystal habits are related, differing only in the relative sizes of their crystal facets. In both cases, the crystals are aligned with their [111] elongation axes parallel to the chain direction. In Itaipu-1, but not Itaipu-3, crystallographic positioning perpendicular to [111] of successive crystals in the magnetosome chain appears to be under biological control. Whereas the large magnetosomes in Itaipu-1 are metastable, single-magnetic domains, magnetosomes in Itaipu-3 are permanent, single-magnetic domains, as in most magnetotactic bacteria.Nós relatamos a aplicação de holografia não-axial e microscopia eletrônica de alta resolução para estudar os hábitos cristalinos de magnetossomos e a microestrutura magnética de dois morfotipos de cocos de bactérias magnetotáticas coletadas em uma lagoa salobra em Itaipu, Brasil. Itaipu-1, o organismo cocóide maior, contémduas cadeias separadas de magnetossomos atipicamente grandes; os cristais dos magnetossomos possuem projeções aproximadamente quadradas, comprimentos deaté 250 nm e são ligeiramente alongados na direção [111] (razão largura/comprimento de aproximadamente 0.9.Os cristais dos magnetossomos em Itaipu-3 possuemcomprimentos até 120 nm, maior alongamento na direção [111

  14. Irregular conformal states and spectral curve: Irregular matrix model approach

    CERN Document Server

    Rim, Chaiho

    2016-01-01

    We present recent developments of irregular conformal conformal states. Irregular vertex operators and their adjoint are used to define the irregular conformal states and their Inner product. Free field formalism can be augmented by screening operators which provide more degrees of freedom. The inner product is conveniently given as partition function of a irregular matrix model. (Deformed) spectral curve is the loop equation of the matrix model at Nekrasov-Shatashivili limit. We present the details of analytic structure of the spectral curve for Virasoso symmetry and its extensions, W-symmetry and super-symmetry.

  15. Irregular marriage: myth and reality

    OpenAIRE

    Gordon, Eleanor

    2013-01-01

    This article examines the historiography, the law, and the practice of irregular marriage in Britain. It argues that there has been a confusion of terms in the historiography of irregular marriage that has served to obscure its meaning, pattern, and incidence. Using evidence from Scotland where irregular marriage continued to be legally valid until 1939 (with one form remaining legally valid until 2006), the article argues that despite its legally valid status, the interpretation of what cons...

  16. Irregular-Time Bayesian Networks

    CERN Document Server

    Ramati, Michael

    2012-01-01

    In many fields observations are performed irregularly along time, due to either measurement limitations or lack of a constant immanent rate. While discrete-time Markov models (as Dynamic Bayesian Networks) introduce either inefficient computation or an information loss to reasoning about such processes, continuous-time Markov models assume either a discrete state space (as Continuous-Time Bayesian Networks), or a flat continuous state space (as stochastic dif- ferential equations). To address these problems, we present a new modeling class called Irregular-Time Bayesian Networks (ITBNs), generalizing Dynamic Bayesian Networks, allowing substantially more compact representations, and increasing the expressivity of the temporal dynamics. In addition, a globally optimal solution is guaranteed when learning temporal systems, provided that they are fully observed at the same irregularly spaced time-points, and a semiparametric subclass of ITBNs is introduced to allow further adaptation to the irregular nature of t...

  17. Analysis of irregularly distributed points

    DEFF Research Database (Denmark)

    Hartelius, Karsten

    1996-01-01

    The present thesis is on the analysis of irregularly distributed points. The main part of the thesis is concerned with enterpolating and restoration of irregularly distribyted points. The least squares methods of kriging and Kalman filtering and the Bayesian restoration method of iterated...... is described as a robust estimator which may be appled straightfor- wardly to a wide range of point patterns and processes when the correlation structure is known. We give a qualitative and quantitative comparison of kriging, Kalman filter and iterated conditional modes. The Kalman filter have in a case study...... and represents an interesting contextuel classifier. Extended Kalman filtering on the other hand seems to be well suited for interpolation in gradually changing environments. Bayesian restoration is applied to a point matching problem, which consists of matching a grid to an image of (irregularly) distributed...

  18. Lexical Semantics and Irregular Inflection

    Science.gov (United States)

    Huang, Yi Ting; Pinker, Steven

    2010-01-01

    Whether a word has an irregular inflection does not depend on its sound alone: compare lie-lay (recline) and lie-lied (prevaricate). Theories of morphology, particularly connectionist and symbolic models, disagree on which nonphonological factors are responsible. We test four possibilities: (1) Lexical effects, in which two lemmas differ in whether they specify an irregular form; (2) Semantic effects, in which the semantic features of a word become associated with regular or irregular forms; (3) Morphological structure effects, in which a word with a headless structure (e.g., a verb derived from a noun) blocks access to a stored irregular form; (4) Compositionality effects, in which the stored combination of an irregular word’s meaning (e.g., the verb’s inherent aspect) with the meaning of the inflection (e.g., pastness) doesn’t readily transfer to new senses with different combinations of such meanings. In four experiments, speakers were presented with existing and novel verbs and asked to rate their past-tense forms, semantic similarities, grammatical structure, and aspectual similarities. We found (1) an interaction between semantic and phonological similarity, coinciding with reported strategies of analogizing to known verbs and implicating lexical effects; (2) weak and inconsistent effects of semantic similarity; (3) robust effects of morphological structure, and (4) robust effects of aspectual compositionality. Results are consistent with theories of language that invoke lexical entries and morphological structure, and which differentiate the mode of storage of regular and irregular verbs. They also suggest how psycholinguistic processes have shaped vocabulary structure over history. PMID:21151703

  19. Cartography of irregularly shaped satellites

    Science.gov (United States)

    Batson, R. M.; Edwards, Kathleen

    1987-01-01

    Irregularly shaped satellites, such as Phobos and Amalthea, do not lend themselves to mapping by conventional methods because mathematical projections of their surfaces fail to convey an accurate visual impression of the landforms, and because large and irregular scale changes make their features difficult to measure on maps. A digital mapping technique has therefore been developed by which maps are compiled from digital topographic and spacecraft image files. The digital file is geometrically transformed as desired for human viewing, either on video screens or on hard copy. Digital files of this kind consist of digital images superimposed on another digital file representing the three-dimensional form of a body.

  20. Evolutionary Models of Irregular Warfare

    Science.gov (United States)

    2013-03-01

    G. (2010) Decentralize, adapt and cooperate. Nature 465:292-293. Sagarin, R. (2012) Learning From the Octopus : How Secrets from Nature Can Help Us...because the concepts map on to important features of modern irregular warfare. For example, small-scale behaviors are increasingly thought to

  1. Characterization of the coccoid cyanobacterium Myxosarcina sp. KIOST-1 isolated from mangrove forest in Chuuk State, Federated States of Micronesia

    Science.gov (United States)

    Kim, Ji Hyung; Lee, JunMo; Affan, Md-Abu; Lee, Dae-Won; Kang, Do-Hyung

    2017-05-01

    Mangrove forests are known to be inhabited by diverse symbiotic cyanobacterial communities that are capable of N2 fixation. To investigate its biodiversity, root sediments were collected from a mangrove forest in Chuuk State, Federated States of Micronesia (FSM), and an entangled yellow-brown coccoid cyanobacterium was isolated. The isolated cyanobacterium was reproduced by multiple fission and eventually produced baeocytes. Phylogenetic analysis revealed that the isolate was most similar to the genera Myxosarcina and Chroococcidiopsis in the order Pleurocapsales. Compositions of protein, lipid and carbohydrate in the cyanobacterial cells were estimated to be 19.4 ± 0.1%, 18.8 ± 0.4% and 31.5 ± 0.1%, respectively. Interestingly, total fatty acids in the isolate were mainly composed of saturated fatty acids and monounsaturated fatty acids, whereas polyunsaturated fatty acids were not detected. Based on the molecular and biochemical characteristics, the isolate was finally classified in the genus Myxosarcina, and designated as Myxosarcina sp. KIOST-1. These results will contribute to better understanding of cyanobacterial biodiversity in the mangrove forest in FSM as well as the genus Myxosarcina, and also will allow further exploitation of its biotechnological potential on the basis of its cellular characteristics.

  2. Roots of Russian Irregular Warfare

    Science.gov (United States)

    2016-12-01

    concluded that the United States has a national policy gap in our own ability to wage “unconventional warfare in the gray zone.”3 That statement...advancing army—few have studied the irregular nature of the campaign waged against Napoleon. Napoleon’s overstretched logistics and the elusiveness of...94 Karl E. Meyer and Shareen Blair Brysac, Tournament of Shadows: The Great Game and the Race for Empire in Central Asia (Washington, DC: Basic

  3. Air Power in Irregular Warfare

    Science.gov (United States)

    2012-12-01

    Intelligence, Surveillance, and Reconnaisance IW Irregular Warfare JFC Joint Force Commander JP Joint Publication xii MCP Malayan Communist Party...being or acting in accord with laws , rules, or established custom.”5 Combined with the Clausewitzian definition of war as “an act of violence meant...Quarterly and Defence Journal , October, 1920), accessed March 21, 2012, http://usacac.army.mil/cac2/cgsc/carl/download/csipubs/lawrence.pdf, 17. 22 Bruce

  4. Identification of Specific Variations in a Non-Motile Strain of Cyanobacterium Synechocystis sp. PCC 6803 Originated from ATCC 27184 by Whole Genome Resequencing.

    Science.gov (United States)

    Ding, Qinglong; Chen, Gu; Wang, Yuling; Wei, Dong

    2015-10-12

    Cyanobacterium Synechocystis sp. PCC 6803 is a widely used model organism in basic research and biofuel biotechnology application. Here, we report the genomic sequence of chromosome and seven plasmids of a glucose-tolerant, non-motile strain originated from ATCC 27184, GT-G, in use at Guangzhou. Through high-throughput genome re-sequencing and verification by Sanger sequencing, eight novel variants were identified in its chromosome and plasmids. The eight novel variants, especially the five non-silent mutations might have interesting effects on the phenotype of GT-G strains, for example the truncated Sll1895 and Slr0322 protein. These resequencing data provide background information for further research and application based on the GT-G strain and also provide evidence to study the evolution and divergence of Synechocystis 6803 globally.

  5. Taxonomic revision and species delimitation of coccoid green algae currently assigned to the genus Dictyochloropsis (Trebouxiophyceae, Chlorophyta).

    Science.gov (United States)

    Škaloud, Pavel; Friedl, Thomas; Hallmann, Christine; Beck, Andreas; Dal Grande, Francesco

    2016-08-01

    Coccoid green algae traditionally classified in Dictyochloropsis have a complex, reticulate chloroplast, when mature, without a pyrenoid. They occupy remarkably diverse ecological niches as free-living organisms or in association with lichen-forming fungi and were recently shown to form two distinct lineages within Trebouxiophyceae. We used a polyphasic approach to revise the taxonomy of the genus. Based on phylogenetic analysis of the 18S rRNA gene, and detailed morphological investigation using comparative conventional light and confocal microscopy, we have assigned these lineages to two genera, Dictyochloropsis and Symbiochloris gen. nov. We have reconsidered the diagnostic generic features as follows: Dictyochloropsis comprises only free-living algae with a reticulate chloroplast, forming lobes in a parallel arrangement at some ontogenetic stages, and which reproduce only by means of autospores. This agrees with Geitler's original diagnosis of Dictyochloropsis, but not with the later emendation by Tschermak-Woess. Consequently, the species of Dictyochloropsis sensu Tschermak-Woess are assigned to Symbiochloris, with new combinations proposed. Symbiochloris encompasses free-living and/or lichenized algae with lobed chloroplasts and that reproduce by forming zoospores characterized by two subapical isokont flagella that emerge symmetrically near the flattened apex. In addition, using coalescent-based approaches, morphological characters and secondary structure of ITS transcripts, we inferred species boundaries and taxonomic relationships within the newly proposed genera. Two species of Dictyochloropsis and nine species of Symbiochloris are delimited, including the newly described species D. asterochloroides, S. handae, S. tropica, and S. tschermakiae. Our results further support the non-monophyly of autosporine taxa within Trebouxiophyceae.

  6. Lopsidedness in dwarf irregular galaxies

    CERN Document Server

    Heller, A B; Almoznino, E; Van Zee, L; Salzer, J J; Heller, Ana B.; Brosch, Noah; Almoznino, Elchanan; Zee, Liese van; Salzer, John J.

    2000-01-01

    We quantify the amplitude of the lopsidedness, the azimuthal angular asymmetry index, and the concentration of star forming regions, as represented by the distribution of the H$\\alpha$ emission, in a sample of 78 late-type irregular galaxies. We bin the observed galaxies in two groups representing blue compact galaxies (BCDs) and low surface brightness dwarf galaxies (LSBs). The light distribution is analysed with a novel algorithm, which allows detection of details in the light distribution pattern. We find that while the asymmetry of the underlying continuum light, representing the older stellar generations, is relatively small, the H$\\alpha$ emission is very asymmetric and is correlated in position angle with the continuum light. We test a model of random star formation over the extent of a galaxy by simulating HII regions in artificial dwarf galaxies. The implication is that random star formation over the full extent of a galaxy may be generated in LSB dwarf-irregular galaxies but not in BCD galaxies.

  7. LDRD Report: Scheduling Irregular Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Boman, Erik G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    This LDRD project was a campus exec fellowship to fund (in part) Donald Nguyen’s PhD research at UT-Austin. His work has focused on parallel programming models, and scheduling irregular algorithms on shared-memory systems using the Galois framework. Galois provides a simple but powerful way for users and applications to automatically obtain good parallel performance using certain supported data containers. The naïve user can write serial code, while advanced users can optimize performance by advanced features, such as specifying the scheduling policy. Galois was used to parallelize two sparse matrix reordering schemes: RCM and Sloan. Such reordering is important in high-performance computing to obtain better data locality and thus reduce run times.

  8. The Dynamics of Equatorial F Layer Irregularities.

    Science.gov (United States)

    2014-09-26

    of irregularities rise through the ionosphere. The patch, after development, has the form of a banana with its long axis magnetic north-south. A...determine the geometrical form of these irregularities. If the irregularities were vertical sheets the maximum intensity would be noted when the ray path...was along the sheet as shown in Figure 6. Vertical sheets , conceived theoretically from upwelling plasma bubbles, were ruled out. Multiplying factors

  9. In-situ determination of the mechanical properties of crawling or non-motile bacteria by Atomic Force Microscopy under physiological conditions without immobilization

    CERN Document Server

    Dhahri, Samia; Marlière, Christian

    2012-01-01

    We present a new, non-perturbative, easy-to-apply method for AFM imaging of living bacteria in their genuine physiological liquid environment. No immobilization protocol, neither chemical nor mechanical, was needed. For the first time, the native gliding (crawling) movements of gram-negative filamentous Nostoc cyanobacteria, along the surface and at speeds up to 200 nm/s, were studied by AFM. With the AFM working in a fast approach/retract mode, no limitation in neither spatial resolution nor imaging rate was detected. Gram positive and non-motile Rhodococcus wratislaviensis bacteria were studied as well. From the approach curves, Young modulus and turgor pressure were measured for both strains and for different gliding speeds. Young modulus is ranging from 20 to 105MPa and turgor pressure from 40 to 310kPa depending on the bacterium and the gliding speed. For Nostoc, spatially limited zones with higher values of stiffness were observed. The related spatial period is much higher than the mean length of nodule...

  10. On Decoding Irregular Tanner Codes

    CERN Document Server

    Even, Guy

    2011-01-01

    We present a new combinatorial characterization for local-optimality of a codeword in irregular Tanner codes. This characterization is a generalization of [Arora, Daskalakis, Steurer; 2009] and [Vontobel; 2010]. The main novelty in this characterization is that it is based on a conical combination of subtrees in the computation trees. These subtrees may have any degree in the local-code nodes and may have any height (even greater than the girth). We prove that local-optimality in this new characterization implies Maximum-Likelihood (ML) optimality and LP-optimality. We also show that it is possible to compute efficiently a certificate for the local-optimality of a codeword given the channel output. We apply this characterization to regular Tanner codes. We prove a lower bound on the noise threshold in channels such as BSC and AWGNC. When the noise is below this lower bound, the probability that LP decoding fails diminishes doubly exponentially in the girth of the Tanner graph. We use local optimality also to ...

  11. Ethical issues in irregular migration research

    NARCIS (Netherlands)

    Duvell, F.; Triandafyllidou, A.; Vollmer, B.

    2008-01-01

    This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

  12. Ethical issues in irregular migration research

    NARCIS (Netherlands)

    Duvell, F.; Triandafyllidou, A.; Vollmer, B.

    2008-01-01

    This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

  13. Capture of Irregular Satellites at Jupiter

    CERN Document Server

    Nesvorny, D; Deienno, R

    2014-01-01

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early Solar System instability when encounters between the outer planets occurred (Nesvorny, Vokrouhlicky & Morbidelli 2007, AJ 133; hereafter NVM07). NVM07 already showed that the irregular satellites of Saturn, Uranus and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary d...

  14. In-Situ Determination of the Mechanical Properties of Gliding or Non-Motile Bacteria by Atomic Force Microscopy under Physiological Conditions without Immobilization

    Science.gov (United States)

    Dhahri, Samia; Ramonda, Michel; Marlière, Christian

    2013-01-01

    We present a study about AFM imaging of living, moving or self-immobilized bacteria in their genuine physiological liquid medium. No external immobilization protocol, neither chemical nor mechanical, was needed. For the first time, the native gliding movements of Gram-negative Nostoc cyanobacteria upon the surface, at speeds up to 900 µm/h, were studied by AFM. This was possible thanks to an improved combination of a gentle sample preparation process and an AFM procedure based on fast and complete force-distance curves made at every pixel, drastically reducing lateral forces. No limitation in spatial resolution or imaging rate was detected. Gram-positive and non-motile Rhodococcus wratislaviensis bacteria were studied as well. From the approach curves, Young modulus and turgor pressure were measured for both strains at different gliding speeds and are ranging from 20±3 to 105±5 MPa and 40±5 to 310±30 kPa depending on the bacterium and the gliding speed. For Nostoc, spatially limited zones with higher values of stiffness were observed. The related spatial period is much higher than the mean length of Nostoc nodules. This was explained by an inhomogeneous mechanical activation of nodules in the cyanobacterium. We also observed the presence of a soft extra cellular matrix (ECM) around the Nostoc bacterium. Both strains left a track of polymeric slime with variable thicknesses. For Rhodococcus, it is equal to few hundreds of nanometers, likely to promote its adhesion to the sample. While gliding, the Nostoc secretes a slime layer the thickness of which is in the nanometer range and increases with the gliding speed. This result reinforces the hypothesis of a propulsion mechanism based, for Nostoc cyanobacteria, on ejection of slime. These results open a large window on new studies of both dynamical phenomena of practical and fundamental interests such as the formation of biofilms and dynamic properties of bacteria in real physiological conditions. PMID:23593493

  15. In-situ determination of the mechanical properties of gliding or non-motile bacteria by atomic force microscopy under physiological conditions without immobilization.

    Directory of Open Access Journals (Sweden)

    Samia Dhahri

    Full Text Available We present a study about AFM imaging of living, moving or self-immobilized bacteria in their genuine physiological liquid medium. No external immobilization protocol, neither chemical nor mechanical, was needed. For the first time, the native gliding movements of Gram-negative Nostoc cyanobacteria upon the surface, at speeds up to 900 µm/h, were studied by AFM. This was possible thanks to an improved combination of a gentle sample preparation process and an AFM procedure based on fast and complete force-distance curves made at every pixel, drastically reducing lateral forces. No limitation in spatial resolution or imaging rate was detected. Gram-positive and non-motile Rhodococcus wratislaviensis bacteria were studied as well. From the approach curves, Young modulus and turgor pressure were measured for both strains at different gliding speeds and are ranging from 20±3 to 105±5 MPa and 40±5 to 310±30 kPa depending on the bacterium and the gliding speed. For Nostoc, spatially limited zones with higher values of stiffness were observed. The related spatial period is much higher than the mean length of Nostoc nodules. This was explained by an inhomogeneous mechanical activation of nodules in the cyanobacterium. We also observed the presence of a soft extra cellular matrix (ECM around the Nostoc bacterium. Both strains left a track of polymeric slime with variable thicknesses. For Rhodococcus, it is equal to few hundreds of nanometers, likely to promote its adhesion to the sample. While gliding, the Nostoc secretes a slime layer the thickness of which is in the nanometer range and increases with the gliding speed. This result reinforces the hypothesis of a propulsion mechanism based, for Nostoc cyanobacteria, on ejection of slime. These results open a large window on new studies of both dynamical phenomena of practical and fundamental interests such as the formation of biofilms and dynamic properties of bacteria in real physiological conditions.

  16. Capture of irregular satellites at Jupiter

    Energy Technology Data Exchange (ETDEWEB)

    Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2014-03-20

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10{sup –8}. This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.

  17. Malária experimental: contaminação de cepas e animais de biotério por eperythrozoon coccoides

    Directory of Open Access Journals (Sweden)

    Heitor Franco de Andrade Jr.

    1986-08-01

    Full Text Available Neste artigo descrevemos a contaminação acidental de uma cepa de malária de roedor (Plasmodium berghei por um hemoparasita (Eperythrozoon coccoides, levando a alterações importantes no comportamento da malária experimental. A demonstração do parasita foi feita por microscopia óptica e eletrônica e a fonte de contaminação foi detectada em roedores normalmente utilizados na manutenção da cepa, obtidos do mesmo biotério. As medidas disponíveis para o controle deste tipo de infecção são discutidas propondo se a utilização de tetra-ciclina em matrizes e posterior utilização de animais Fl não tratados. Comenta-se a importância deste tipo de contaminação experimental.

  18. Malária experimental: contaminação de cepas e animais de biotério por eperythrozoon coccoides

    OpenAIRE

    Heitor Franco Andrade Jr.; Márcia Dalastra Laurenti; Hiro Goto; Maria Irma Seixas Duarte; Carlos Eduardo Pereira Corbett

    1986-01-01

    Neste artigo descrevemos a contaminação acidental de uma cepa de malária de roedor (Plasmodium berghei) por um hemoparasita (Eperythrozoon coccoides), levando a alterações importantes no comportamento da malária experimental. A demonstração do parasita foi feita por microscopia óptica e eletrônica e a fonte de contaminação foi detectada em roedores normalmente utilizados na manutenção da cepa, obtidos do mesmo biotério. As medidas disponíveis para o controle deste tipo de infecção são discuti...

  19. Irregular Variability In Kepler Photometry

    Science.gov (United States)

    Schlecker, Martin

    2016-12-01

    The transit method is the most successful tool for exoplanet discovery to date. With more than half of all known exoplanets discovered by Kepler using this method, the mission also revealed a number of objects with dimming events that defy the common explanations, the most prominent being KIC 8462852 aka ``Tabby's star''. I embarked on a search for objects with such irregular transit signatures in the data of K2, the two-wheeled successor mission of Kepler. My method is a combination of automated pre-selection of targets showing downward flux excursions and visual light curve inspection of the selected subset comprising about SI{1.5}% of the initial sample. In addition, I developed a tool to constrain the effective temperature of a planet-hosting star from photometry alone. This software finds broad application in any science case where a photometric spectral type estimate is necessary. I used existing transit models and Bayesian inference to perform a Markov Chain Monte Carlo (MCMC) analysis of a planetary candidate I discovered. This putative gas giant is in a SI{1.32}day circular orbit with an exceptionally tight orbital radius of a ≈ 0.012 AU. My analysis revealed a scaled planetary radius of R_{p}/R_star = 0.0927±0.0026 and an edge-on orientation with an inclination i=89.8+3.0-3.4. EPIC 217393088.01 is one of the closest-orbiting exoplanets ever detected and the first giant planet with such a small orbital radius. An additional major finding of my search is EPIC 220262993, which exhibits aperiodic, asymmetric dips in flux with rapid dimming rates and up to SI{˜25}% depth, lasting for SIrange{2}{4} day. In previous works based on optical and mid-infrared photometry, this object was inconsistently classified as a possible quasar or a white dwarf. We conducted follow-up observations both photometrically with GROND on the MPI/ESO SI{2.2} meter telescope in La Silla (Chile) and spectroscopically with FIRE on the Magellan/Baade SI{6.5} meter telescope. With

  20. NOTE - Meiotic irregularities in Capsicum L. species

    Directory of Open Access Journals (Sweden)

    Margarete Magalhães Souza

    2012-01-01

    Full Text Available Cytogenetic and pollen viability (PV studies were performed in pepper accessions, Capsicum chinense and Capsicum baccatum. Irregularities such as laggard and univalent chromosomes, bridges, problems in the spindle fibers and cytomixis were observed, especially in C. baccatum which was the most unstable genotype. In the post-meiotic products, irregularities were observed, on average, at 20 % of the microspores in C. baccatum and 17 % in C. chinense. PV in C. baccatum was below 70 %, while in C. chinense, it was above 80 %. Meiotic irregularities in Capsicum, mainly in C. baccatum, considering the low PV estimated, were significant but not impeditive for fertilization.

  1. Robust Spectral Estimation of Track Irregularity

    Institute of Scientific and Technical Information of China (English)

    Fu Wenjuan; Chen Chunjun

    2005-01-01

    Because the existing spectral estimation methods for railway track irregularity analysis are very sensitive to outliers, a robust spectral estimation method is presented to process track irregularity signals. The proposed robust method is verified using 100 groups of clean/contaminated data reflecting he vertical profile irregularity taken from Bejing-Guangzhou railway with a sampling frequency of 33 data every 10 m, and compared with the Auto Regressive (AR) model. The experimental results show that the proposed robust estimation is resistible to noise and insensitive to outliers, and is superior to the AR model in terms of efficiency, stability and reliability.

  2. The irregularity of two types of trees

    OpenAIRE

    Liu, Yang; Li, Jianxi; Chee, Wai

    2015-01-01

    The irregularity of a graph G is defined as the sum of weights |d(u) − d(v)| of all edges uv of G, where d(u) and d(v) are the degrees of the vertices u and v in G, respectively. In this paper, some structural properties on trees with maximum (or minimum) irregularity among trees with given degree sequence and trees with given branching number are explored, respectively. Moreover, the corresponding trees with maximum (or minimum) irregularity are also found, respectively.

  3. Detection of vanC1 and vanC2 Genes in an Enterococcal Isolate and vanC Genes in non-Motile Enterococcus spp.

    Directory of Open Access Journals (Sweden)

    Mazaheri Nezhad Fard

    2014-10-01

    Full Text Available Background In recent decades, bacterial antibiotic resistance (especially in enterococci has become a significant problem for human and veterinary medicine. One of the most important antibiotic resistances in enterococci, vancomycin resistance, is encoded by van gene family. Objectives The aim of this study was to investigate antibiotic resistance to vancomycin in enterococci and the genes responsible for this resistance. Materials and Methods Two-hundred and thirty enterococcal isolates from pigs (207 isolates, chickens (15 isolates and humans (eight isolates were phenotypically and genotypically tested for resistance to vancomycin by minimum inhibitory concentration (MIC and polymerase chain reaction (PCR. The van genes were confirmed by gene sequencing. Results Of the total isolates, 19% were phenotypically resistant to vancomycin, while nearly 15% contained either vanC1 or vanC2 gene. One resistant E. casseliflavus isolate with pig origin (MIC > 8 μg/mL contained both vanC1 and vanC2 genes. Furthermore, one vanC1 was found in a sensitive E. faecalis isolate of pig origin (MIC ≤ 4 μg/mL and one vanC2 in a resistant E. faecium isolate of chicken origin (MIC > 32 μg/mL. These genes were not accompanied by other van genes. Other detected genes were vanA in 11 E. faecium isolates of chicken origin (MIC > 32 μg/mL. No vanB genes were found. Gene sequencing results showed 100% identity with GenBank reference genes. Conclusions The current report is the first report on the detection of vanC1 and vanC2 genes in one enterococcal species with pig origin. This report is important as it proves the horizontal transfer of various vanC genes to one species possibly due to the compatibility class of plasmids. Furthermore, detection of vanC genes in E. faecalis and E. faecium isolates is important as it suggests that resistance to vancomycin in non-motile enterococci can be encoded by several mechanisms.

  4. The K-Spectrum of Ionospheric Irregularities

    DEFF Research Database (Denmark)

    D'Angelo, N.; Pécseli, Hans; Petersen, P. I.

    1975-01-01

    Laboratory measurements in a cesium plasma device indicate that the wave number (power) spectrum of irregularities produced by the Farley instability is of the type P(K) ∝ K −β, where β ≃ 3.5-3.8.......Laboratory measurements in a cesium plasma device indicate that the wave number (power) spectrum of irregularities produced by the Farley instability is of the type P(K) ∝ K −β, where β ≃ 3.5-3.8....

  5. Wideband irregular-shaped fractal antennas

    OpenAIRE

    Kolesov, V. V.; Krupenin, S. V.

    2007-01-01

    This paper proposes an algorithm of generating fully reproducible irregular fractal structures for antenna design. Three types of pseudorandom fractal clusters are introduced. The multi-frequency behavior of the irregular-shaped fractal antennas is studied by means of numerical analysis. The antenna behavior is studied under feeder displacement. As shown by numerical results feeder displacements allow one to control the spatial-frequency antenna characteristics.

  6. Locating irregularly shaped clusters of infection intensity

    Directory of Open Access Journals (Sweden)

    Niko Yiannakoulias

    2010-05-01

    Full Text Available Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until recently, cluster detection methods were limited in their ability to detect irregular spatial patterns, and limited to finding clusters that were roughly circular in shape. This approach has less power to detect irregularly-shaped, yet important spatial anomalies, particularly at high spatial resolutions. We employ a new method of finding irregularly-shaped spatial clusters at micro-geographical scales using both simulated and real data on Schistosoma mansoni and hookworm infection intensities. This method, which we refer to as the “greedy growth scan”, is a modification of the spatial scan method for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the “greedy growth scan” is a suitable method for exploratory geographical analysis of infection intensity data when irregular shapes are suspected, especially at micro-geographical scales.

  7. Restructuring surface tessellation with irregular boundary conditions

    Directory of Open Access Journals (Sweden)

    Tsung-Hsien Wang

    2014-12-01

    Full Text Available In this paper, the surface tessellation problem is explored, in particular, the task of meshing a surface with the added consideration of incorporating constructible building components. When a surface is tessellated into discrete counterparts, certain unexpected conditions usually occur at the boundary of the surface, in particular, when the surface is being trimmed. For example, irregularly shaped panels form at the trimmed edges. To reduce the number of irregular panels that may form during the tessellation process, this paper presents an algorithmic approach to restructuring the surface tessellation by investigating irregular boundary conditions. The objective of this approach is to provide an alternative way for freeform surface manifestation from a well-structured discrete model of the given surface.

  8. Evidence for a facultative mutualist nutritional relationship between the green coccoid alga Bracteacoccus sp. (Chlorophyceae) and the zoosporic fungus Rhizidium phycophilum (Chytridiomycota).

    Science.gov (United States)

    Picard, Kathryn T; Letcher, Peter M; Powell, Martha J

    2013-05-01

    Symbiotic interactions between fungi and photosynthetic partners are common among derived fungal lineages. The only fungal-phototroph interactions thus far reported from the early diverging zoosporic fungi are parasitic in nature. Rhizidium phycophilum is a terrestrial, saprotrophic chytrid, which appears to be able to enter a facultative mutualism with a coccoid green alga in the absence of refractory organic material, such as pollen and chitin. Liquid and solid culturing methods were used in a series of differential fitness experiments in conjunction with microscopic analyses to characterize the interaction between R. phycophilum and the alga. The alga in this partnership is identified as a member of the genus Bracteacoccus. Under certain culturing conditions, algal cells grown in coculture with R. phycophilum were shown to grow larger and more prolifically than when cultured axenically under the same conditions. Additionally, dialysis experiments demonstrate that R. phycophilum does not parasitize Bracteacoccus sp., and can be cultured in media infused with unknown algal exudates. Rhizidium phycophilum and Bracteacoccus sp. represent the first facultative positive interaction between a zoosporic fungus and a photoautotroph and may prove a tractable system for modelling interactions between early fungi and plants. Copyright © 2013 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  9. Spelling Pronunciations: Transforming Irregularity into Regularity

    Science.gov (United States)

    Landerl, Karin; Thaler, Verena; Reitsma, Pieter

    2008-01-01

    In a 10-day training, the efficacy of spelling pronunciations on German speaking 5th-graders' spelling skills for irregular words was examined. Poor spellers were less efficient in learning the spelling pronunciations than age-adequate spellers. On post-tests, 1 week after the last training day and between 5 and 12 weeks after post-test 1, poor…

  10. Informal labor and irregular migrant workers

    NARCIS (Netherlands)

    M.J. van Meeteren (Masja)

    2013-01-01

    textabstractIrregular migrants, also referred to as “undocumented migrants” or “illegal migrants,” are immigrants who do not have legal permission to stay in the country they have migrated to and frequently take on informal and precarious employment. They may have entered the country legally – on a

  11. Color Survey of the Irregular Planetary Satellites

    Science.gov (United States)

    Graykowski, Ariel; Jewitt, David

    2016-10-01

    Irregular satellites are characterized by their larger orbital distance from their planet, their high eccentricity and their high inclination, all indicating that they were captured. However, the mechanism of capture and the location of origin of the satellites remain unknown. We are conducting a photometric survey of the irregular satellites of the giant planets using the LRIS instrument on the 10-meter telescope at the Keck Observatory in Hawaii. The measured colors will be compared to other planetary bodies in search for similarities and differences that may reflect upon the origin of the satellites. For example, if irregular satellites were captured from the Kuiper Belt then some should contain the ultrared material that is common in the trans-Neptunian and Centaur populations. If the irregular satellites of Jupiter were captured from the same source population as the Jovian Trojans, then it is natural to expect that the surface properties of satellites and Trojans should be the same. We will present initial results of this work.

  12. default and irregular attendance at treatment centres

    African Journals Online (AJOL)

    Leprosy control in the post leprosaria abolition years in Nigeria: Reasons for default and irregular ... leprosy seen at the four leprosy clinics in Anambra State in a face to face interview. ..... India, 1974; 46: 46-48. 7. Leonard G, Sangure A, ...

  13. Enhanced wave absorption through irregular interfaces

    Science.gov (United States)

    Félix, S.; Sapoval, B.; Filoche, M.; Asch, M.

    2009-01-01

    The diffraction and absorption of waves by a system with both absorbing properties and irregular geometry is an open physical problem. A more reachable and closely related question is the understanding of wave oscillations in confined systems containing an absorbing material with an irregular shape. This has to be solved to understand why anechoic chambers (electromagnetic or acoustic) do work better with irregular absorbing walls. The answer to this question could also be used in other fields such as light or microwave absorption, or also to improve the performances of break-waters in order to damp sea-waves. It is found here that, in resonators containing an irregular shaped absorbent material, there appears a new type of mode localization. This phenomemon, that we call "astride" localization, describes the fact that these modes exist in both the lossless and the lossy regions. It is these modes that are particularly efficient in dissipating the energy of waves excited in the non-absorbing region.

  14. Spelling Pronunciations: Transforming Irregularity into Regularity

    Science.gov (United States)

    Landerl, Karin; Thaler, Verena; Reitsma, Pieter

    2008-01-01

    In a 10-day training, the efficacy of spelling pronunciations on German speaking 5th-graders' spelling skills for irregular words was examined. Poor spellers were less efficient in learning the spelling pronunciations than age-adequate spellers. On post-tests, 1 week after the last training day and between 5 and 12 weeks after post-test 1, poor…

  15. Acoustic and Linguistic Interdependencies of Irregular Phonation

    Science.gov (United States)

    2010-05-01

    falther forward subsystems. The subglottal subsystem, including the abdominal muscles, intercostals , diaphragm, lungs, branching airways, and trachea...labeled prosodically, which limits us to acoustic and phonetic deductions about irregular phonation. TIMIT was developed as a joint eff0l1 between

  16. Photometric Survey of the Irregular Satellites

    CERN Document Server

    Grav, T; Gladman, B; Aksnes, K; Grav, Tommy; Holman, Matthew J.; Gladman, Brett; Aksnes, Kaare

    2003-01-01

    We present BVRI colors of 13 Jovian and 8 Saturnian irregular satellites obtained with the 2.56m Nordic Optical Telescope on La Palma, the 6.5m Magellan Baade Telescope on La Campanas, and the 6m MMT on Mt. Hopkins. The observations were performed between December 2001 to March 2002. Nearly all of the known irregular satellites can be divided into two distinct classes based on their colors. One, the grey color class, has the similar colors to the C-type asteroid, and the other, the light red color class, has colors similar to P/D-type asteroids. We also find at least one object, the Jovian irregular J XXIII Kalyke, that has colors similar to the red colored Centaurs/TNOs, although its classification is unsecure. We also find that there is a correlation between the physical properties and dynamical properties of the irregular satellites. Most of the dynamical clusters have homogeneous colors, which points to single homogeneous progenitors being cratered or fragmented as the source of each individual cluster. T...

  17. Irregular wavelet frames on L2(Rn)

    Institute of Scientific and Technical Information of China (English)

    YANG Deyun; ZHOU Xingwei

    2005-01-01

    In this paper, we present the conditions on dilation parameter {sj }j that ensure a discrete irregular wavelet system {Snj/2ψ(sj·-bk)}j∈(Z),k∈(Z)n to be a frame on L2(Rn),and for the wavelet frame we consider the perturbations of translation parameter b and frame function ψ respectively.

  18. Locating irregularly shaped clusters of infection intensity

    DEFF Research Database (Denmark)

    Yiannakoulias, Niko; Wilson, Shona; Kariuki, H. Curtis

    2010-01-01

    Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until...

  19. Irregularly Shaped Space-Filling Truncated Octahedra

    Science.gov (United States)

    Hanson, John Robert

    2008-01-01

    For any parent tetrahedron ABCD, centroids of selected sub-tetrahedra form the vertices of an irregularly shaped space-filling truncated octahedron. To reflect these properties, such a figure will be called an ISTO. Each edge of the ISTO is parallel to and one-eighth the length of one of the edges of tetrahedron ABCD and the volume of the ISTO is…

  20. Generalisation of Regular and Irregular Morphological Patterns.

    Science.gov (United States)

    Prasada, Sandeep; and Pinker, Steven

    1993-01-01

    When it comes to explaining English verbs' patterns of regular and irregular generalization, single-network theories have difficulty with the former, rule-only theories with the latter process. Linguistic and psycholinguistic evidence, based on observation during experiments and simulations in morphological pattern generation, independently call…

  1. Fitting Irregular Shape Figures into Irregular Shape Areas for the Nesting Problem in the Leather Industry

    Directory of Open Access Journals (Sweden)

    Guevara-Palma Luis

    2015-01-01

    Full Text Available The nesting problem of irregular shapes within irregular areas has been studied from several approaches due to their application in different industries. The particular case of cutting leather involves several restrictions that add complexity to this problem, it is necessary to generate products that comply with the quality required by customers This paper presents a methodology for the accommodation of irregular shapes in an irregular area (leather considering the constraints set by the footwear industry, and the results of this methodology when applied by a computer system. The scope of the system is to develop a working prototype that operates under the guidelines of a commercial production line of a sponsor company. Preliminary results got a reduction of 70% of processing time and improvement of 5% to 7% of the area usage when compared with manual accommodation.

  2. Magnetic fields in Local Group dwarf irregulars

    CERN Document Server

    Chyzy, Krzysztof T; Beck, Rainer; Bomans, Dominik J

    2011-01-01

    We clarify whether strong magnetic fields can be effectively generated in typically low-mass dwarf galaxies and what is the role of dwarf galaxies in the magnetization of the Universe. We performed a search for radio emission and magnetic fields in an unbiased sample of 12 Local Group (LG) irregular and dwarf irregular galaxies with the 100m Effelsberg telescope at 2.64 and 4.85GHz. Magnetic fields in LG dwarfs are three times weaker than in the normal spirals (6muG) are observed only in dwarfs of extreme characteristics while typical LG dwarfs are not suitable objects for efficient supply of magnetic fields to the intergalactic medium.

  3. Generating Performance Models for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

    2017-05-30

    Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

  4. A Hybrid Heuristics for Irregular Flight Recovery

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiu-li; ZHU Jin-fu; GAO Qiang

    2010-01-01

    Adverse weather conditions, congestion at airports, and mechanical failures often disrupt regular flight schedules. The irregular flight recovery problem aims to recover these schedules through reassignments of flights and cancellations. In this article, we develop the classic resource assignment model for the irregular flight recovery problem, and a new hybrid heuristic procedure based on greedy random adaptive search procedure (GRASP) and simulated annealing algorithm is presented to solve this problem. As compared with the original GRASP method, the proposed algorithm demonstrates quite a high global optimization capability. Computational experiments on large-scale problems show that the proposed procedure is able to generate feasible revised flight schedules of good quality in less than five seconds.

  5. Parallel Programming Strategies for Irregular Adaptive Applications

    Science.gov (United States)

    Biswas, Rupak; Biegel, Bryan (Technical Monitor)

    2001-01-01

    Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance for such computations. In this work, we examine two typical irregular adaptive applications, Dynamic Remeshing and N-Body, under competing programming methodologies and across various parallel architectures. The Dynamic Remeshing application simulates flow over an airfoil, and refines localized regions of the underlying unstructured mesh. The N-Body experiment models two neighboring Plummer galaxies that are about to undergo a merger. Both problems demonstrate dramatic changes in processor workloads and interprocessor communication with time; thus, dynamic load balancing is a required component.

  6. Conditions for Adopting an Irregular Defense Strategy

    Science.gov (United States)

    2014-06-01

    however, believed that the irregular campaign needed to be conducted in the rural and urban area simultaneously.38 Fidel Castro and Che Guevara...shape; they were conscripts and unwilling to fight. The Batista regime was already unpopular when Castro and Guevara came along, and here is where the...scale publicity effort driven by Castro who had always shown a great capability to turn even unsuccessful military actions into propaganda triumphs

  7. Synchronizing data from irregularly sampled sensors

    Energy Technology Data Exchange (ETDEWEB)

    Uluyol, Onder

    2017-07-11

    A system and method include receiving a set of sampled measurements for each of multiple sensors, wherein the sampled measurements are at irregular intervals or different rates, re-sampling the sampled measurements of each of the multiple sensors at a higher rate than one of the sensor's set of sampled measurements, and synchronizing the sampled measurements of each of the multiple sensors.

  8. Gelatinous plankton: irregularities rule the world (sometimes)

    OpenAIRE

    Boero, F.; Bouillon, J; GRAVILI C.; Miglietta, M. P.; Parsons, T. R.; Piraino, S.

    2008-01-01

    In spite of being one of the most relevant components of the biosphere, the plankton-benthos network is still poorly studied as such. This is partly due to the irregular occurrence of driving phenomena such as gelatinous plankton pulses in this realm. Gelatinous plankters rely on their life cycles and histories to exploit temporarily abundant resources with an undeniable, but often overlooked, impact on marine food webs. Dramatic increases of gelatinous filter-feeders and/or carnivores (both ...

  9. When You Visit Your Doctor: Irregular Menstrual Periods

    Science.gov (United States)

    ... delivered to your inbox ! When You Visit Your Doctor - Irregular Menstrual Periods Irregular Menstrual Periods Updated: January ... Have you ever had difficulty getting pregnant? Your Doctor Might Examine the Following Body Structures or Functions: ...

  10. Total irregular labeling of butterfly network on level two

    Science.gov (United States)

    Nurdin

    2017-08-01

    Previous results related to the concepts of the total irregular labeling of a graph indicate that the butterfly network was one of some graphs which have not been specified in term of the total irregularity strengths. This paper aimed to determine the total vertex irregularity strength, the total edge irregularity strength, and the total irregularity strength of butterfly network on level 2. The assessment of three parameters of butterfly network was conducted by determining the lower bound and the upper bound. The lower bound was analyzed based on the characteristics of the graph and other proponent theorems, while upper bound was analyzed by constructing a function. In this paper we determine that the total vertex irregularity strength, the total edge irregularity strength, and the total irregularity strength of butterfly network are 4, 6, and 6, respectively.

  11. Photometric survey of the irregular satellites

    Science.gov (United States)

    Grav, Tommy; Holman, Matthew J.; Gladman, Brett J.; Aksnes, Kaare

    2003-11-01

    We present BVRI colors of 13 jovian and 8 saturnian irregular satellites obtained with the 2.56 m Nordic Optical Telescope on La Palma, the 6.5 m Magellan Baade Telescope on La Campanas, and the 6.5 m MMT on Mt. Hopkins. The observations were performed from December 2001 to March 2002. The colors of the irregular satellites vary from grey to light red. We have arbitrarily divided the known irregular satellites into two classes based on their colors. One, the grey color class, has similar colors to the C-type asteroids, and the other, the light red color class, has colors similar to P/D-type asteroids. We also find at least one object, the jovian irregular J XXIII Kalyke, that has colors similar to the red colored Centaurs/TNOs, although its classification is insecure. We find that there is a correlation between the physical properties and dynamical properties of the irregular satellites. Most of the dynamical clusters have homogeneous colors, which points to single homogeneous progenitors being cratered or fragmented as the source of each individual cluster. The heterogeneously colored clusters are most easily explained by assuming that there are several dynamical clusters in the area, rather than just one, or that the parent body was a differentiated, heterogeneous body. By analyzing simple cratering/fragmentation scenarios, we show that the heterogeneous colored S IX Phoebe cluster, is most likely two different clusters, a grey colored cluster centered on S IX Phoebe and a light red colored cluster centered on S/2000 S 1. To which of these two clusters the remaining saturnian irregulars with inclinations close to 174° belong is not clear from our analysis, but determination of their colors should help constrain this. We also show through analysis of possible fragmentation and dispersion of the six known uranian irregulars that they most likely make up two clusters, one centered on U XVI Caliban and another centered on U XVII Sycorax. We further show that

  12. Length measurements of mid-latitude scintillation irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Macdougall, J.W. (Western Ontario, University, London (Canada))

    1992-04-01

    The lengths of irregularities which produce 150-MHz amplitude scintillations have been measured at 43 deg N, 81 deg W (geographic) using arrays of receivers with large spacings. The average length (major axis radius) of the irregularities was 6.1 km. This is much shorter than expected and implies that the measurements are of 'young' irregularities, less than 1 minute old. These irregularities appear to be a large, 25-50-percent perturbation of the background density. 8 refs.

  13. Vertex Operators for Irregular Conformal Blocks: Supersymmetric Case

    CERN Document Server

    Polyakov, Dimitri

    2016-01-01

    We construct supersymmetric irregular vertex operators of arbitrary rank, appearing in the colliding limit of primary fields. We find that the structure of the supersymmetric irregular vertices differs significantly from the bosonic case: upon supersymmetrization, the irregular operators are no longer the eigenstates of positive Virasoro and $W_N$ generators but block-diagonalize them. We relate the block-diagonal structure of the irregular vertices to contributions of the Ramond sector to the colliding limit.

  14. Hitchin Equation, Irregular Singularity, and $N=2$ Asymptotical Free Theories

    CERN Document Server

    Nanopoulos, Dimitri

    2010-01-01

    In this paper, we study irregular singular solution to Hitchin's equation and use it to describe four dimensional $N=2$ asymptotically free gauge theories. For $SU(2)$ $A$ type quiver, two kinds of irregular singularities besides one regular singularity are needed for the solution of Hitchin's equation; We then classify irregular singularities needed for the general $SU(N)$ $A$ type quiver.

  15. On irregularity strength of disjoint union of friendship graphs

    Directory of Open Access Journals (Sweden)

    Ali Ahmad

    2013-11-01

    Full Text Available We investigate the vertex total and edge total modication of the well-known irregularity strength of graphs. We have determined the exact values of the total vertex irregularity strength and the total edge irregularity strength of a disjoint union of friendship graphs.

  16. 16 CFR 501.6 - Cellulose sponges, irregular dimensions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of...

  17. Testing Of Choiced Ceramics Cutting Tools At Irregular Interrupted Cut

    Science.gov (United States)

    Kyncl, Ladislav; Malotová, Šárka; Nováček, Pavel; Nicielnik, Henryk; Šoková, Dagmar; Hemžský, Pavel; Pitela, David; Holubjak, Jozef

    2015-12-01

    This article discusses the test of removable ceramic cutting inserts during machining irregular interrupted cut. Tests were performed on a lathe, with the preparation which simulated us the interrupted cut. By changing the number of plates mounted in a preparation it simulate us a regular or irregular interrupted cut. When with four plates it was regular interrupted cut, the remaining three variants were already irregular cut. It was examined whether it will have the irregular interrupted cutting effect on the insert and possibly how it will change life of inserts during irregular interrupted cut (variable delay between shocks).

  18. Irregular satellite capture during planetary resonance passage

    Science.gov (United States)

    Ćuk, Matija; Gladman, Brett J.

    2006-08-01

    The passage of Jupiter and Saturn through mutual 1:2 mean-motion resonance has recently been put forward as explanation for their relatively high eccentricities [Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F., 2005. Nature 435, 459-461] and the origin of Jupiter's Trojans [Morbidelli, A., Levison, H.F., Tsiganis, K., Gomes, R., 2005. Nature 435, 462-465]. Additional constraints on this event based on other small-body populations would be highly desirable. Since some outer satellite orbits are known to be strongly affected by the near-resonance of Jupiter and Saturn ("the Great Inequality"; Ćuk, M., Burns, J.A., 2004b. Astron. J. 128, 2518-2541), the irregular satellites are natural candidates for such a connection. In order to explore this scenario, we have integrated 9200 test particles around both Jupiter and Saturn while they went through a resonance-crossing event similar to that described by Tsiganis et al. [Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F., 2005. Nature 435, 459-461]. The test particles were positioned on a grid in semimajor axes and inclinations, while their initial pericenters were put at just 0.01 AU from their parent planets. The goal of the experiment was to find out if short-lived bodies, spiraling into the planet due to gas drag (or alternatively on orbits crossing those of the regular satellites), could have their pericenters raised by the resonant perturbations. We found that about 3% of the particles had their pericenters raised above 0.03 AU (i.e. beyond Iapetus) at Saturn, but the same happened for only 0.1% of the particles at Jupiter. The distribution of surviving particles at Saturn has strong similarities to that of the known irregular satellites. If saturnian irregular satellites had their origin during the 1:2 resonance crossing, they present an excellent probe into the early Solar System's evolution. We also explore the applicability of this mechanism for Uranus, and find that only some of the uranian

  19. Subsonic Mechanical Alignment of Irregular Grains

    CERN Document Server

    Lazarian, Alex

    2007-01-01

    We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the right and left directions. The grains tend to align with long axes perpendicular to magnetic field, which corresponds to Davis-Greenstein predictions, but does not involve magnetic field. For rather conservative factors characterizing the grain helicity and scattering efficiency of impinging atoms, the alignment of helical grains is much more efficient than the Gold-type alignment processes.

  20. Artificial periodic irregularities in the auroral ionosphere

    Directory of Open Access Journals (Sweden)

    M.T. Rietveld

    Full Text Available Artificial periodic irregularities (API are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the

  1. Ultrastructural study on the coccoid forms of Helicobacter pylori in the tissues of carcinoma%癌组织中幽门螺杆菌球形体的超微结构研究

    Institute of Scientific and Technical Information of China (English)

    于东红; 王启之; 贾继辉; 唐素兰; 王萍

    2006-01-01

    目的:揭示癌组织中幽门螺杆菌(Hp)球形体的超微结构特征.方法:通过透射电镜观察Hp球形体感染阳性的4例胃癌、2例食管癌组织中Hp球形体的超微结构.结果:Hp球形体多散在性分布于癌巢、癌间质以及进入癌细胞、巨噬细胞等细胞胞质.Hp球形体与其他细菌的L型样,形态不规则,呈多形性,且大小不等、胞质电子密度不等、胞壁缺失等.Hp球形体有A、B两种类型,A种体积较小,胞浆致密,细胞膜上带有鞭毛,此种活性较强;B种体积较大,胞浆疏松,细胞膜上不带鞭毛,此种可能已蜕变结论:Hp球形体仍具有活性,在Hp的传播、相关疾病的治疗复发和相关肿瘤的发生过程中起重要的作用.%Objective:This study was designed to characterize the ultrastructure of the coccoid Helicobacter pylori(H. pylori) forms in the tissues of carcinoma.Methods:Transmission electron microscopy(TEM) technique was used to examine the structure of coccoid H. pylori in 4 cases of gastric carcinoma and 2 cases of esophageal carcinoma.Results:It was found that the coccoid H. pylori were scattered in cancer nest and cancer interspace,some of which enterded cancer cells,macrophages and other cells.The coccoid H. pylori appeared to be similar to the L-forms of other bacteria with varying cell shape and size,different cytoplasmic electron densities and defects in cell wall.Two types of coccoid H. pylori could be distinguished in the tissues of carcinoma by TEM.Type A was smaller with higher electron density in the cytoplasma,and flagellation on the cell membrane,suggesting that it could be viable.However,the type B was larger with lower electron density in the cytoplasma,and no flagellation on the cell membrane,suggesting that it could be a degenerative form.Conclusions:The coccoid forms of H.pulori still have certain degree of viability,thus they may play an important role in the transmission of H. pylori,the relapse of H. pylori related disease

  2. Legal aspects of the EU policy on irregular immigration

    Directory of Open Access Journals (Sweden)

    Voinikov Vadim

    2015-12-01

    Full Text Available This article addresses the issues pertaining to the adoption and development of legislation on irregular migration in the context of uncontrolled growth in the number of immigrants from North Africa and the Middle East to the EU. The article attempts at studying the EU legislation on irregular migration, classifying it, and analysing the prospects of EU migration legislation in the light of an increase in irregular immigration into the EU. The author systematises, classifies the current EU legislation on irregular immigration, and analyses the conditions, in which this legislation was developed. Using the legislation analysis method, the author proposes the following system of EU legislation on irregular immigration: rules preventing assistance to irregular immigration, rules preventing employment of irregular immigrants, rules on the return of irregular migrants and readmission, rules on border control, and rules on collaboration with third countries. The author pays special attention to analysing the current state of irregular immigration to the EU, which was dubbed the ‘greatest migration crisis in Europe’. The conclusion is that the European Union succeeded in the development of pioneering legislation on irregular immigration, which can serve as the basis for reception by other states. However, changes in the political and economic situation in the EU’s southern borderlands made the current legal mechanisms incapable of withstanding new threats. It necessitates a radical reform of the legislation on irregular immigration.

  3. Statistical detection of systematic election irregularities

    Science.gov (United States)

    Klimek, Peter; Yegorov, Yuri; Hanel, Rudolf; Thurner, Stefan

    2012-01-01

    Democratic societies are built around the principle of free and fair elections, and that each citizen’s vote should count equally. National elections can be regarded as large-scale social experiments, where people are grouped into usually large numbers of electoral districts and vote according to their preferences. The large number of samples implies statistical consequences for the polling results, which can be used to identify election irregularities. Using a suitable data representation, we find that vote distributions of elections with alleged fraud show a kurtosis substantially exceeding the kurtosis of normal elections, depending on the level of data aggregation. As an example, we show that reported irregularities in recent Russian elections are, indeed, well-explained by systematic ballot stuffing. We develop a parametric model quantifying the extent to which fraudulent mechanisms are present. We formulate a parametric test detecting these statistical properties in election results. Remarkably, this technique produces robust outcomes with respect to the resolution of the data and therefore, allows for cross-country comparisons. PMID:23010929

  4. IRREGULAR WAVELET FRAMES AND GABOR FRAMES

    Institute of Scientific and Technical Information of China (English)

    Ole Christensen; Sergio Favier; Felipe Zó

    2001-01-01

    Given g ∈ L2 (R), we consider irregular wavelet systems of theform {λ g(λj x-kb) }j z. kz, where λj >0 and b>0. Sufficient conditions for the wavelet system to constitute a frame for L2(R) are given. For a class of functions g ∈ L 2 (R) we prove that certain growth conditions on {λj} will lead to frames, and that some other types of sequences exclude the frame property. We also give a sufficient condition for a Gabor system {exib(j,x)g(x-λh)}jzn,kz to be a frame.CLC Number:O17 Document ID:AAuthor Resume:Ole Christensen;E-mail: Ole. Christensen@mat. dtu. dk Sergio Favier and Felipe Zó ;e-mails : sfavier@unsl. edu. ar fzo@unsl. edu. ar References:[1]Casaza,P.G. and Christensen,O.,Weyl-Heisenberg Frames for Subspaces of L2(R),Proc.Amer. Math. Soc. ,129(2001),145-154.[2]Casazza,P.G. and Christensen,O. ,Classifying Certain Irregular Gabor Frames,preprint[2]001.[3]Christensen,O. and Lindner,A. ,Lower Bounds for Finite Wavelet and Gabor Systems,Appr. Theory and Appl.,17(2001),17-31.[4]Chui,C.K. and Shi,X. ,Inequalities of Litdewood-Paley Type for Frames and Wavelets,SIAM J. Math. Anal. ,24:1(1993),263-277.[5]Daubechies,I. ,Ten Lectures on Wavelets,SIAM,Philadelphia,1992.[6]Favier,S. and Zalik,R. ,On the Stability of Frames and Riesz Bases,Appl. Comp. Ham.Anal. ,2(1995),160-173.[7]Feichtinger,H.G. and Strohmer,T. ,(Eds.),Gabor Analysis and Algorithms : Theory and Applications,Birkhauser,1998.[8]Heil,C.E. and Walnut,D.F. ,Continuous and Discrete Wavelet Transforms,SIAM Review,31:4(1989),628-666.[9]Sun,W. and Zhou,X. ,Irregular Wavelet Frames,Science in China (Series A),43:2(2000),122-127.Manuscript Received:2001年7月10日Manuscript Revised:2001年7月23日Published:2001年9月1日

  5. Vibrations of strongly irregular or fractal resonators

    Science.gov (United States)

    Sapoval, B.; Gobron, Th.

    1993-05-01

    It is shown on a specific example that fractal boundary conditions drastically alter the properties of wave excitations in space. The low-frequency part of the vibration spectrum of a finite-range fractal drum is computed using an analogy between the Helmoltz equation and the diffusion equation. The irregularity of the frontier is found to influence strongly the density of states at low frequency. The fractal perimeter generates a specific screening effect. Very near the frontier, the decrease of the wave form is related directly to the behavior of the harmonic measure. The possibility of localization of the vibrations is qualitatively discussed and we show that localized modes may exist at low frequencies if the geometrical structures possess narrow paths. Possible application of these results to the interpretation of thermal properties of binary glasses is briefly discussed.

  6. A parametric approach to irregular fatigue prediction

    Science.gov (United States)

    Erismann, T. H.

    1972-01-01

    A parametric approach to irregular fatigue protection is presented. The method proposed consists of two parts: empirical determination of certain characteristics of a material by means of a relatively small number of well-defined standard tests, and arithmetical application of the results obtained to arbitrary loading histories. The following groups of parameters are thus taken into account: (1) the variations of the mean stress, (2) the interaction of these variations and the superposed oscillating stresses, (3) the spectrum of the oscillating-stress amplitudes, and (4) the sequence of the oscillating-stress amplitudes. It is pointed out that only experimental verification can throw sufficient light upon possibilities and limitations of this (or any other) prediction method.

  7. Measurement of ionospheric large-scale irregularity

    Institute of Scientific and Technical Information of China (English)

    韩文焌; 郑怡嘉; 张喜镇

    1996-01-01

    Based on the observations of a meter-wave aperture synthesis radio telescope,as the scale length of ionospheric irregularity is greatly larger than the baseline length of interferometer,the phase error induced by the output signal of interferometer due to ionosphere is proportional to the baseline length and accordingly the expressions for extracting the information about ionosphere are derived.By using the ray theory and considering that the antenna is always tracking to the radio source in astronomical observation,the wave motion expression of traveling ionospheric disturbance observed in the total electron content is also derived,which is consistent with that obtained from the conception of thin-phase screen;then the Doppler velocity due to antenna tracking is introduced.Finally the inversion analysis for the horizontal phase velocity of TID from observed data is given.

  8. Evaluating transport in irregular pore networks

    CERN Document Server

    Klimenko, Dimitri A; Klimenko, Alexander Y; 10.1103/PhysRevE.86.011112

    2012-01-01

    A general approach for investigating transport phenomena in porous media is presented. This approach has the capacity to represent various kinds of irregularity in porous media without the need for excessive detail or computational effort. The overall method combines a generalized Effective Medium Approximation (EMA) with a macroscopic continuum model in order to derive a transport equation with explicit analytical expressions for the transport coefficients. The proposed form of the EMA is an anisotropic and heterogeneous extension of Kirkpatrick's EMA [Rev. Mod. Phys. 45, 574 (1973)] which allows the overall model to account for microscopic alterations in connectivity (with the locations of the pores and the orientation and length of the throat) as well as macroscopic variations in transport properties. A comparison to numerical results for randomly generated networks with different properties is given, indicating the potential for this methodology to handle cases that would pose significant difficulties to ...

  9. Irregular activity arises as a natural consequence of synaptic inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Terman, D., E-mail: terman@math.ohio-state.edu [Department of Mathematics, The Ohio State University, Columbus, Ohio 43210 (United States); Rubin, J. E., E-mail: jonrubin@pitt.edu [Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Diekman, C. O., E-mail: diekman@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

    2013-12-15

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

  10. Modelling Of Random Vertical Irregularities Of Railway Tracks

    Directory of Open Access Journals (Sweden)

    Podwórna M.

    2015-08-01

    Full Text Available The study presents state-of-the-art in analytical and numerical modelling of random vertical irregularities of continuously welded ballasted railway tracks. The common model of railway track irregularity vertical profiles is applied, in the form of a stationary and ergodic Gaussian process in space. Random samples of track irregularity vertical profiles are generated with the Monte-Carlo method. Based on the numerical method developed in the study, the minimum and recommended sampling number required in the random analysis of railway bridges and number of frequency increments (harmonic components in track irregularity vertical profiles simulation are determined. The lower and upper limits of wavelengths are determined based on the literature studies. The approach yields track irregularity random samples close to reality. The track irregularity model developed in the study can be used in the dynamic analysis of railway bridge / track structure / highspeed train systems.

  11. Decomposing Oriented Graphs into Six Locally Irregular Oriented Graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien; Renault, Gabriel

    2016-01-01

    An undirected graph G is locally irregular if every two of its adjacent vertices have distinct degrees. We say that G is decomposable into k locally irregular graphs if there exists a partition E1∪E2∪⋯∪Ek of the edge set E(G) such that each Ei induces a locally irregular graph. It was recently co...

  12. The Analysis and Creation of Track Irregularities Using TRAKVU

    OpenAIRE

    1998-01-01

    The accuracy of the results from a rail vehicle dynamic model is dependent on the realism of the track input to the model. An important part of the track input is the irregularities that exist on actual track. This study analyzes the irregularities inherent in railroad track geometry data, and provides an analytical method for creating track data with the irregularities for use as the input to a dynamic model. Track data, measured from various classes of track, was ...

  13. Advances in electron dosimetry of irregular fields; Avances en dosimetria de electrones de campos irregulares

    Energy Technology Data Exchange (ETDEWEB)

    Mendez V, J. [Departamento de Radioterapia, Instituto de Enfermedades Neoplasicas, Avenida Angamos Este 2520, Lima 34 (Peru)

    1998-12-31

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm{sup 2} with percentile error less than 1 % . (Author)

  14. Natural convection inside an irregular porous cavity; Conveccao natural no interior de uma cavidade porosa irregular

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia

    1990-12-31

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author) 6 refs., 10 figs., 7 tabs.

  15. Ionospheric irregularities at Antarctic using GPS measurements

    Indian Academy of Sciences (India)

    Sunita Tiwari; Amit Jain; Shivalika Sarkar; Sudhir Jain; A K Gwal

    2012-04-01

    The purpose of this work is to study the behaviour of the ionospheric scintillation at high latitude during geomagnetically quiet and disturbed conditions which is one of the most relevant themes in the space weather studies. Scintillation is a major problem in navigation application using GPS and in satellite communication at high latitudes. Severe amplitude fading and strong scintillation affect the reliability of GPS navigational system and satellite communication. To study the effects of the ionospheric scintillations, GPS receiver installed at Antarctic station Maitri (Geog. 70.76°S; 11.74°E) was used. The data is collected by using GISTM 4004A, NOVATEL’S GPS receiver during March 2008. Studies show that percentage occurrence of phase scintillation is well correlated with geomagnetic activity during the observation period. The result also shows that very intense scintillations can degrade GPS based location determination due to loss of lock of satellites. These findings indicate that the dependence of scintillations and irregularity occurrence on geomagnetic activity is associated with the magnetic local time (MLT). Large number of patches are reported and their activity depends on the magnetic activity index.

  16. Multiresolution Analysis Adapted to Irregularly Spaced Data

    Directory of Open Access Journals (Sweden)

    Anissa Mokraoui

    2009-01-01

    Full Text Available This paper investigates the mathematical background of multiresolution analysis in the specific context where the signal is represented by irregularly sampled data at known locations. The study is related to the construction of nested piecewise polynomial multiresolution spaces represented by their corresponding orthonormal bases. Using simple spline basis orthonormalization procedures involves the construction of a large family of orthonormal spline scaling bases defined on consecutive bounded intervals. However, if no more additional conditions than those coming from multiresolution are imposed on each bounded interval, the orthonormal basis is represented by a set of discontinuous scaling functions. The spline wavelet basis also has the same problem. Moreover, the dimension of the corresponding wavelet basis increases with the spline degree. An appropriate orthonormalization procedure of the basic spline space basis, whatever the degree of the spline, allows us to (i provide continuous scaling and wavelet functions, (ii reduce the number of wavelets to only one, and (iii reduce the complexity of the filter bank. Examples of the multiresolution implementations illustrate that the main important features of the traditional multiresolution are also satisfied.

  17. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  18. Design strategies for irregularly adapting parallel applications

    Energy Technology Data Exchange (ETDEWEB)

    Oliker, Leonid; Biswas, Rupak; Shan, Hongzhang; Sing, Jaswinder Pal

    2000-11-01

    Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance of dynamically adapting computations. In this work, we examine two major classes of adaptive applications, under five competing programming methodologies and four leading parallel architectures. Results indicate that it is possible to achieve message-passing performance using shared-memory programming techniques by carefully following the same high level strategies. Adaptive applications have computational work loads and communication patterns which change unpredictably at runtime, requiring dynamic load balancing to achieve scalable performance on parallel machines. Efficient parallel implementations of such adaptive applications are therefore a challenging task. This work examines the implementation of two typical adaptive applications, Dynamic Remeshing and N-Body, across various programming paradigms and architectural platforms. We compare several critical factors of the parallel code development, including performance, programmability, scalability, algorithmic development, and portability.

  19. Evaluating transport in irregular pore networks

    Science.gov (United States)

    Klimenko, Dimitri A.; Hooman, Kamel; Klimenko, Alexander Y.

    2012-07-01

    A general approach for investigating transport phenomena in porous media is presented. This approach has the capacity to represent various kinds of irregularity in porous media without the need for excessive detail or computational effort. The overall method combines a generalized effective medium approximation (EMA) with a macroscopic continuum model in order to derive a transport equation with explicit analytical expressions for the transport coefficients. The proposed form of the EMA is an anisotropic and heterogeneous extension of Kirkpatrick's EMA [Rev. Mod. Phys.RMPHAT0034-686110.1103/RevModPhys.45.574 45, 574 (1973)] which allows the overall model to account for microscopic alterations in connectivity (with the locations of the pores and the orientation and length of the throat) as well as macroscopic variations in transport properties. A comparison to numerical results for randomly generated networks with different properties is given, indicating the potential for this methodology to handle cases that would pose significant difficulties to many other analytical models.

  20. Over rough and smooth : Amputee gait on an irregular surface

    NARCIS (Netherlands)

    Curtze, C.; Hof, A.L.; Postema, K.; Otten, B.

    2011-01-01

    When negotiating irregular surfaces, the control of dynamic stability is challenged. In this study, we compared the adjustments in stepping behaviour and arm-swing of 18 unilateral transtibial amputees and 17 able-bodied participants when walking on flat and irregular surfaces. Experimental findings

  1. Edge-partitioning graphs into regular and locally irregular components

    DEFF Research Database (Denmark)

    Bensmail, Julien; Stevens, Brett

    2016-01-01

    A graph is locally irregular if every two adjacent vertices have distinct degrees. Recently, Baudon et al. introduced the notion of decomposition into locally irregular subgraphs. They conjectured that for almost every graph G, there exists a minimum integer χ'irr(G) such that G admits an edge-pa...

  2. Irregular conformal block, spectral curve and flow equations

    CERN Document Server

    Choi, Sang Kwan; Zhang, Hong

    2015-01-01

    Irregular conformal block is motivated by the Argyres-Douglas type of N=2 super conformal gauge theory. We investigate the classical/NS limit of the irregular conformal block using spectral curve on a Riemann surface with irregular punctures, which is equivalent to the loop equation of irregular matrix model. The spectral curve is reduced to the second order (Virasoro symmetry, $SU(2)$ for the gauge theory) and third order ($W_3$ symmetry, $SU(3)$) differential equations of a polynomial with finite degree. The Virasoro and W symmetry generate flow equations in the spectral curve and determine the irregular conformal block, hence the partition function of the Argyres-Douglas theory ala AGT conjecture.

  3. School setting and irregular lunch consumption among adolescents

    DEFF Research Database (Denmark)

    Pagh Pedersen, Trine; Holstein, Bjørn Evald; Rasmussen, Mette

    level variables and irregular lunch consumption. Lunch consumption was measured by lunch frequency questions. Results: We found that the school level factors, “Availability to canteen” and “Adult present in lunch breaks” were associated with irregular lunch consumption. Students with no access...... to canteen had a lower risk of having irregular lunch consumption OR=0.77 (0.62-0.96). Students with no adult present in lunch breaks had a higher risk of irregular lunch consumption OR=1.62 (1.32-1.99). Having irregular lunch consumption was associated with the following individual characteristics: boy, 7th...... the association. Conclusion: The structural setting of the school was associated with children and adolescents’ regularity of lunch consumption in a multilevel model controlled for individual level factors. From the findings we can conclude that availability of canteen and school stall did not promote regular...

  4. Imaging HF-induced large-scale irregularities above HAARP

    Science.gov (United States)

    Djuth, Frank T.; Reinisch, Bodo W.; Kitrosser, David F.; Elder, John H.; Snyder, A. Lee; Sales, Gary S.

    2006-02-01

    The University of Massachusetts-Lowell digisonde is used with the HAARP high-frequency (HF), ionospheric modification facility to obtain radio images of artificially-produced, large-scale, geomagnetic field-aligned irregularities. F region irregularities generated with the HAARP beam pointed in the vertical and geomagnetic field-aligned directions are examined in a smooth background plasma. It is found that limited large-scale irregularity production takes place with vertical transmissions, whereas there is a dramatic increase in the number of source irregularities with the beam pointed parallel to the geomagnetic field. Strong irregularity production appears to be confined to within ~5° of the geomagnetic zenith and does not fill the volume occupied by the HF beam. A similar effect is observed in optical images of artificial airglow.

  5. Processor Allocation for Optimistic Parallelization of Irregular Programs

    CERN Document Server

    Versaci, Francesco

    2012-01-01

    Optimistic parallelization is a promising approach for the parallelization of irregular algorithms: potentially interfering tasks are launched dynamically, and the runtime system detects conflicts between concurrent activities, aborting and rolling back conflicting tasks. However, parallelism in irregular algorithms is very complex. In a regular algorithm like dense matrix multiplication, the amount of parallelism can usually be expressed as a function of the problem size, so it is reasonably straightforward to determine how many processors should be allocated to execute a regular algorithm of a certain size (this is called the processor allocation problem). In contrast, parallelism in irregular algorithms can be a function of input parameters, and the amount of parallelism can vary dramatically during the execution of the irregular algorithm. Therefore, the processor allocation problem for irregular algorithms is very difficult. In this paper, we describe the first systematic strategy for addressing this pro...

  6. Magnetic fields in Local Group dwarf irregulars

    Science.gov (United States)

    Chyży, K. T.; Weżgowiec, M.; Beck, R.; Bomans, D. J.

    2011-05-01

    Aims: We wish to clarify whether strong magnetic fields can be effectively generated in typically low-mass dwarf galaxies and to assess the role of dwarf galaxies in the magnetization of the Universe. Methods: We performed a search for radio emission and magnetic fields in an unbiased sample of 12 Local Group (LG) irregular and dwarf irregular galaxies with the 100-m Effelsberg telescope at 2.64 GHz. Three galaxies were detected. A higher frequency (4.85 GHz) was used to search for polarized emission in five dwarfs that are the most luminous ones in the infrared domain, of which three were detected. Results: Magnetic fields in LG dwarfs are weak, with a mean value of the total field strength of regulated mainly by the star-formation surface density (with the power-law exponent of 0.30 ± 0.04) or by the gas surface density (with the exponent 0.47 ± 0.09). In addition, we find systematically stronger fields in objects of higher global star-formation rate. The dwarf galaxies follow a similar far-infrared relationship (with a slope of 0.91 ± 0.08) to that determined for high surface brightness spiral galaxies. The magnetic field strength in dwarf galaxies does not correlate with their maximum rotational velocity, indicating that a small-scale rather than a large-scale dynamo process is responsible for producting magnetic fields in dwarfs. If magnetization of the Universe by galactic outflows is coeval with its metal enrichment, we show that more massive objects (such as Lyman break galaxies) can efficiently magnetize the intergalactic medium with a magnetic field strength of about 0.8 nG out to a distance of 160-530 kpc at redshifts 5-3, respectively. Magnetic fields that are several times weaker and shorter magnetization distances are expected for primordial dwarf galaxies. We also predict that most star-forming local dwarfs might have magnetized their surroundings up to a field strength about 0.1 μG within about a 5 kpc distance. Conclusions: Strong magnetic

  7. Orbital maneuvers around irregular shaped bodies

    Science.gov (United States)

    Venditti, Flaviane; Rocco, E. M.; Almeida Prado, A. B.

    2013-05-01

    Abstract (2,250 Maximum Characters): In the solar system there are many small bodies called asteroids. The large majority of these bodies are located in the asteroid belt, between the orbits of the planets Mars and Jupiter. The Near- Earth Objects, or NEOs, are objects with perihelion below 1.3AU, which include comets and asteroids. The NEOs are considered to have orbits passing close to the Earth’s orbit and, in the case of asteroids, are called Near-Earth Asteroids (NEAs). Among the NEAs there are bodies considered potentially hazardous asteroids (PHAs), whose minimum orbit intersection distance with Earth is 0.05AU and that have absolute magnitude (H) of 22, which would mean an asteroid of at least 110-240 meters, depending on its albedo. One of the major characteristic of the asteroids is the irregular shape, causing the dynamics of orbits around these bodies to be different from a spherical shaped one. The fact that an object is not spherical generates a perturbation on the gravitational field. The disturbing force can be determined considering the shape of the specific body. A satellite orbiting this body would suffer the effects of this perturbation, but knowing the disturbing force, it’s possible to correct and control the orbit according to the desired mission. The polyhedron method is a traditional way to model an asteroid by dividing the object into smaller parts. The data used on this work are composed by a combination of triangular faces. The total disturbing force is a sum of the force on each piece of the model. Therefore, after the simulations are obtained, it’s possible to apply the desired corrections of the perturbation using continuous low thrust in closed loop, making it possible to perform maneuvers near these bodies. One of the important applications of the study shown above is in the ASTER mission, that is under study by INPE and several other Brazilian academic institutions, which goal is to send a spacecraft to an asteroid and then

  8. Determining Ionospheric Irregularity Spectral Density Function from Japan GEONET

    Science.gov (United States)

    Lay, E. H.; Light, M. E.; Parker, P. A.; Carrano, C. S.; Haaser, R. A.

    2015-12-01

    Japan's GEONET GPS network is the densest GPS monitoring network in the world, with 1200+ receivers over the area of Japan. Measuring and calibrating the integrated total electron content (TEC) from each station has been done in many cases to provide detailed maps of ionospheric disturbances over Japan. We use TEC measurements from Japan's GEONET array to determine an empirically derived description of the 2-dimensional scale sizes of spatial irregularities above Japan. The contributions from various scale sizes will be included in a statistical description for the irregularity spectral density (ISD) function. We will compare the statistics of the spatial irregularities between calm and moderately scintillated conditions.

  9. The irregularities of the sunspot cycle and their theoretical modelling

    CERN Document Server

    Choudhuri, Arnab Rai

    2013-01-01

    The 11-year sunspot cycle has many irregularities, the most promi- nent amongst them being the grand minima when sunspots may not be seen for several cycles. After summarizing the relevant observational data about the irregularities, we introduce the flux transport dynamo model, the currently most successful theoretical model for explaining the 11-year sunspot cycle. Then we analyze the respective roles of nonlinearities and random fluctuations in creating the irregularities. We also discuss how it has recently been realized that the fluctuations in meridional circula- tion also can be a source of irregularities. We end by pointing out that fluctuations in the poloidal field generation and fluctuations in meridional circulation together can explain the occurrences of grand minima.

  10. Land Elevation TINs (Triangulated Irregular Networks) for Jefferson County, WI

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Land Elevation TINs (Triangulated Irregular Networks) in this directory are generated from 2 foot contour lines from Jefferson County. Little is known about the...

  11. Approximate design calculation methods for radiation streaming in shield irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Toshimasa; Hirao, Yoshihiro [Ship Research Inst., Mitaka, Tokyo (Japan); Yoritsune, Tsutomu

    1997-10-01

    Investigation and assessment are made for approximate design calculation methods of radiation streaming in shield irregularities. Investigation is made for (1) source, (2) definition of streaming radiation components, (3) calculation methods of streaming radiation, (4) streaming formulas for each irregularity, (5) difficulties in application of streaming formulas, etc. Furthermore, investigation is made for simple calculation codes and albedo data. As a result, it is clarified that streaming calculation formulas are not enough to cover various irregularities and their accuracy or application limit is not sufficiently clear. Accurate treatment is not made in the formulas with respect to the radiation behavior for slant incidence, bend part, offset etc., that results in too much safety factors in the design calculation and distrust of the streaming calculation. To overcome the state and improve the accuracy of the design calculation for shield irregularities, it is emphasized to assess existing formulas and develop better formulas based on systematic experimental studies. (author)

  12. Irregular sampling for multivariate band-limited functions

    Institute of Scientific and Technical Information of China (English)

    SUN; Wenchang(孙文昌); ZHOU; Xingwei(周性伟)

    2002-01-01

    In this paper, we present some new algorithms to reconstruct multivariate band-limited functionsfrom irregular sampled values, which allow more arbitrary sampling points and lower sampling densities thanknown results.

  13. What Are the Common Treatments for Menstrual Irregularities?

    Science.gov (United States)

    ... the menstrual problem, such as counseling for an eating disorder or extreme excercise Treatment for menstrual irregularities that ... Home Contact Accessibility Web Policies and Notices FOIA Facebook Twitter Pinterest YouTube RSS NIH...Turning Discovery Into ...

  14. Helicopters in Irregular Warfare: Algeria, Vietnam, and Afghanistan

    Science.gov (United States)

    2013-06-13

    the political group associated with the Algerian nationalist independence movement GALAT Groupement d’ Aviation Légère de l’Armée de Terre ...unique from most conflicts because the expeditionary forces’ parent country rarely perceives an existential threat.19 The lack of perceived threat...dominance rarely guarantees success in irregular warfare.22 Instead, success in irregular warfare requires synergy between government and military efforts

  15. On irregular conformal blocks, with an application to the Painlev\\'e functions

    CERN Document Server

    Nagoya, Hajime

    2015-01-01

    We develop the theory on irregular conformal blocks of the Virasoro algebra. In previous studies, expansions of irregular conformal blocks at regular singular points were obtained as degeneration limits of regular conformal blocks, however, expansions of those at irregular singular points were not understood clearly. This is because precise definitions of irregular vertex operators had not given before. In this paper, we give precise definitions of irregular vertex operators of two kinds and conjecture that they exist uniquely. Then, we define irregular conformal blocks with at most two irregular singular points, as expectation values of the given irregular vertex operators. Our definitions give an understanding of expansions of irregular conformal blocks and are enable us to obtain expansions at irregular singular points. As an application, we give conjectural formulas of Fourier expansions of the tau functions of the fifth and fourth Painlev\\'e functions, using expansions of irregular conformal blocks at an...

  16. Irregularity excitation associated with charged dust cloud boundary layers

    Science.gov (United States)

    Mahmoudian, A.; Scales, W. A.

    2012-02-01

    Irregularity generation associated with dust cloud expansion through a background plasma along a magnetic field is investigated. Because of the dust charging process, a boundary layer is produced, separating the dusty plasma generated and the background plasma. It is observed that under appropriate conditions, localized plasma irregularities may be generated in this boundary layer. Theoretical and computational models are used to study the evolution of relevant plasma instabilities thought to play a dominant role in irregularity production. An electron flow develops along the boundary layer of the dust cloud, and plasma irregularities are generated in response to this flow. Several aspects of the cloud's structure (thickness of the boundary layer, average particle size and density, collisional processes, and cloud expansion speed) and the ambient plasma are varied to determine the effect of these quantities on the resulting irregularities. The relevance of these results to past experimental observations in space and the laboratory for applications to the expansion of naturally or artificially created dust clouds is discussed.

  17. Dark Matter and the Chemical Evolution of Irregular Galaxies

    Directory of Open Access Journals (Sweden)

    L. Carigi

    2001-01-01

    Full Text Available We present three types of chemical evolution models for irregular galaxies: closed-box with continuous star formation rates (SFRs, closed-box with burstin g SFRs, and O-rich outflow with continuous SFRs. We discuss the chemical evolution of the irregular galaxies NGC 1560 and II Zw 33, and a "typical" irregular galaxy. The fraction of low-mass stars needed by our models is larger than that derived for the solar vicinity, but similar to that found in globular clusters. For our typical irregular galaxy we need a mass fraction of about 40% in the form of substellar objects plus non baryonic dark matter inside the Holmberg radius, in good agreement with the results derived for NGC 1560 and II Zw 33 where we do have an independent estimate of the mass fraction in non baryonic dark matter. Closed-box models are better than O-rich outflow models in explaining the C/O and Z/O observed values for our typical irregular galaxy.

  18. Regulation of Irregular Neuronal Firing by Autaptic Transmission

    Science.gov (United States)

    Guo, Daqing; Wu, Shengdun; Chen, Mingming; Perc, Matjaž; Zhang, Yangsong; Ma, Jingling; Cui, Yan; Xu, Peng; Xia, Yang; Yao, Dezhong

    2016-05-01

    The importance of self-feedback autaptic transmission in modulating spike-time irregularity is still poorly understood. By using a biophysical model that incorporates autaptic coupling, we here show that self-innervation of neurons participates in the modulation of irregular neuronal firing, primarily by regulating the occurrence frequency of burst firing. In particular, we find that both excitatory and electrical autapses increase the occurrence of burst firing, thus reducing neuronal firing regularity. In contrast, inhibitory autapses suppress burst firing and therefore tend to improve the regularity of neuronal firing. Importantly, we show that these findings are independent of the firing properties of individual neurons, and as such can be observed for neurons operating in different modes. Our results provide an insightful mechanistic understanding of how different types of autapses shape irregular firing at the single-neuron level, and they highlight the functional importance of autaptic self-innervation in taming and modulating neurodynamics.

  19. Photometry of Irregular Satellites of Uranus and Neptune

    CERN Document Server

    Grav, T

    2004-01-01

    We present BVR photometric colors of six Uranian and two Neptunian irregular satellites, collected using the Magellan Observatory (Las Campanas, Chile) and the Keck Observatory, (Manua Kea, Hawaii). The colors range from neutral to light red, and like the Jovian and the Saturnian irregulars (Grav et al. 2003) there is an apparent lack of the extremely red objects found among the Centaurs and Kuiper belt objects. The Uranian irregulars can be divided into three possible dynamical families, but the colors collected show that two of these dynamical families, the Caliban and Sycorax-clusters, have heterogeneous colors. Of the third possible family, the 168-degree cluster containing two objects with similar average inclinations but quite different average semi-major axis, only one object (U XXI Trinculo) was observed. The heterogeneous colors and the large dispersion of the average orbital elements leads us to doubt that they are collisional families. We favor single captures as a more likely scenario. The two nep...

  20. BVR Color Survey of the Jovian Irregular Satellites

    Science.gov (United States)

    Rettig, T. W.; Walsh, K.

    2002-09-01

    BVR colors and magnitudes are presented for four Jovian irregular prograde satellites (Himalia J6, Elara J7, Lysithea J10 and Leda J13) and four irregular retrograde satellites (Pasiphae J8, Sinope J9, Carme J11 and Ananke J12). All eight have generally `solar' colors but the retrograde group has slightly redder and more diverse colors. The strikingly similar colors of the four prograde satellites suggests the parent planetesimal was likely very homogeneous. The four retrograde satellites show diversity in color that suggests a heterogeneous progenitor and thus, variations in pre-capture formation history. The absolute magnitudes and revised diameters are presented. We also report new colors and diameters for two Uranian irregular satellites (Caliban (S/1997 U1) and Sycorax (S/1997 U2)). The Uranian satellite colors are slightly redder than the eight Jovian satellites studied.

  1. A BVR Colors of Eight Jovian Irregular Satellites -- Evolutionary Implications

    Science.gov (United States)

    Rettig, T. W.; Walsh, K.

    2001-11-01

    We present BVR colors and magnitudes for four Jovian irregular prograde satellites (Himalia J6, Elara J7, Lysithea J10 and Leda J13) and four irregular retrograde satellites (Pasiphae J8, Sinope J9, Carme J11 and Ananke J12). All eight have generally `solar' colors but the retrograde group has slightly redder and more diverse colors. The strikingly similar colors of the four prograde satellites suggests the parent planetesimal was likely very homogeneous. The four retrograde satellites show diversity in color that suggests a heterogeneous progenitor and thus, variations in pre-capture formation history. The absolute magnitudes and revised diameters are presented. We also report new colors and diameters for two Uranian irregular satellites (Caliban (S/1997 U1) and Sycorax (S/1997 U2)) that are slightly redder than any of these Jovian satellites.

  2. Dynamical Configurations of Celestial Systems Comprised of Multiple Irregular Bodies

    CERN Document Server

    Jiang, Yu; Baoyin, Hexi; Li, Junfeng

    2016-01-01

    This manuscript considers the main features of the nonlinear dynamics of multiple irregular celestial body systems. The gravitational potential, static electric potential, and magnetic potential are considered. Based on the three established potentials, we show that three conservative values exist for this system, including a Jacobi integral. The equilibrium conditions for the system are derived and their stability analyzed. The equilibrium conditions of a celestial system comprised of n irregular bodies are reduced to 12n minus 9 equations. The dynamical results are applied to simulate the motion of multiple-asteroid systems. The simulation is useful for the study of the stability of multiple irregular celestial body systems and for the design of spacecraft orbits to triple asteroid systems discovered in the solar system. The dynamical configurations of the five triple-asteroid systems 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, and 136617 1994CC, and the six-body system 134340 Pluto are calculated and...

  3. Track Irregularity Time Series Analysis and Trend Forecasting

    Directory of Open Access Journals (Sweden)

    Jia Chaolong

    2012-01-01

    Full Text Available The combination of linear and nonlinear methods is widely used in the prediction of time series data. This paper analyzes track irregularity time series data by using gray incidence degree models and methods of data transformation, trying to find the connotative relationship between the time series data. In this paper, GM (1,1 is based on first-order, single variable linear differential equations; after an adaptive improvement and error correction, it is used to predict the long-term changing trend of track irregularity at a fixed measuring point; the stochastic linear AR, Kalman filtering model, and artificial neural network model are applied to predict the short-term changing trend of track irregularity at unit section. Both long-term and short-term changes prove that the model is effective and can achieve the expected accuracy.

  4. A 2-D NUMERICAL IRREGULAR WAVE TANK AND ITS VERIFICATION

    Institute of Scientific and Technical Information of China (English)

    LI Ben-xia; YU Xi-ping; YU Yu-xiu

    2005-01-01

    A two-dimensional numerical irregular wave tank based on the potential wave theory was developed.A source term was used inside the domain to generate waves, and outgoing waves were dissipated by sponge layers and transmitted by radiation boundary.The σ-coordinate transformation was introduced to map the time-dependent irregular physical domain to a fixed regular computational domain, and thus the free surface and bottom boundary conditions could be implemented precisely.The model was verified by simulating the nonlinear regular and irregular wave propagation on constant-depth water, as well as regular waves reflected from a vertical wall, and satisfactory agreement between numerical results and analytical solutions was obtained.The present numerical model is proved to be an effective tool for a long-duration simulation of coastal wave dynamics where the wave reflection is significant.

  5. Inferring the Coronal Density Irregularity from EUV Spectra

    CERN Document Server

    Hahn, Michael

    2016-01-01

    Understanding the density structure of the solar corona is important for modeling both coronal heating and the solar wind. Direct measurements are difficult because of line-of-sight integration and possible unresolved structures. We present a new method for quantifying such structure using density-sensitive EUV line intensities to derive a density irregularity parameter, a relative measure of the amount of structure along the line of sight. We also present a simple model to relate the inferred irregularities to physical quantities, such as the filling factor and density contrast. For quiet Sun regions and interplume regions of coronal holes, we find a density contrast of at least a factor of three to ten and corresponding filling factors of about 10-20%. Our results are in rough agreement with other estimates of the density structures in these regions. The irregularity diagnostic provides a useful relative measure of unresolved structure in various regions of the corona.

  6. Modeling of Plasma Irregularities in Expanding Ionospheric Dust Clouds

    Science.gov (United States)

    Fu, H.; Scales, W.; Mahmoudian, A.; Bordikar, M. R.

    2009-12-01

    Natural dust layers occur in the earth’s mesosphere (50km-85km). Plasma irregularities are associated with these natural dust layers that produce radar echoes. Recently, an Ionospheric sounding rocket experiment was performed to investigate the plasma irregularities in upper atmospheric dust layers. The Charged Aerosol Release Experiment (CARE) uses a rocket payload injection of particles in the ionosphere to determine the mechanisms for enhanced radar scatter from plasma irregularities embedded in artificial dusty plasma in space. A 2-D hybrid computational model is described that may be used to study a variety of irregularities in dusty space plasmas which may lead to radar echoes. In this model, the dust and ions are both treated with Particle-In-Cell method while the dust charge varies with time based on the standard dust Orbit Motion Limited charging model. A stochastic model is adopted to remove particle ions due to the dust charging process. Electrons are treated with a fluid model including the parallel dynamics of magnetic fields. Fourier spectral methods with a predictor-corrector time advance are used to solve it. This numerical model will be used to investigate the electrodynamics and several possible plasma irregularity generation mechanisms after the creation of an artificial dust layer. The first is the dust ion-acoustic instability due to the drift of dust relative to the plasma. The instability saturates by trapping some ions. The effects of dust radius and dust drift velocity on plasma irregularities will be analyzed further. Also, a shear- driven instability in expanding dusty clouds is investigated.

  7. Irregular Shaped Building Design Optimization with Building Information Modelling

    Directory of Open Access Journals (Sweden)

    Lee Xia Sheng

    2016-01-01

    Full Text Available This research is to recognise the function of Building Information Modelling (BIM in design optimization for irregular shaped buildings. The study focuses on a conceptual irregular shaped “twisted” building design similar to some existing sculpture-like architectures. Form and function are the two most important aspects of new buildings, which are becoming more sophisticated as parts of equally sophisticated “systems” that we are living in. Nowadays, it is common to have irregular shaped or sculpture-like buildings which are very different when compared to regular buildings. Construction industry stakeholders are facing stiff challenges in many aspects such as buildability, cost effectiveness, delivery time and facility management when dealing with irregular shaped building projects. Building Information Modelling (BIM is being utilized to enable architects, engineers and constructors to gain improved visualization for irregular shaped buildings; this has a purpose of identifying critical issues before initiating physical construction work. In this study, three variations of design options differing in rotating angle: 30 degrees, 60 degrees and 90 degrees are created to conduct quantifiable comparisons. Discussions are focused on three major aspects including structural planning, usable building space, and structural constructability. This research concludes that Building Information Modelling is instrumental in facilitating design optimization for irregular shaped building. In the process of comparing different design variations, instead of just giving “yes or no” type of response, stakeholders can now easily visualize, evaluate and decide to achieve the right balance based on their own criteria. Therefore, construction project stakeholders are empowered with superior evaluation and decision making capability.

  8. Characterizing spontaneous irregular behavior in coupled map lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dobyns, York [PEAR, Princeton University Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene Wilhelmstrasse 3a, Freiburg 79098 (Germany)]. E-mail: haa@igpp.de

    2005-04-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties.

  9. Robust Fusion of Irregularly Sampled Data Using Adaptive Normalized Convolution

    NARCIS (Netherlands)

    Pham, T.Q.; Van Vliet, L.J.; Schutte, K.

    2006-01-01

    We present a novel algorithm for image fusion from irregularly sampled data. The method is based on the framework of normalized convolution (NC), in which the local signal is approximated through a projection onto a subspace. The use of polynomial basis functions in this paper makes NC equivalent to

  10. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archive

  11. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archive

  12. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

  13. Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Andersen, Nis Korsgaard; Søgaard, Emil

    2014-01-01

    We study water drop roll-off at superhydrophobic surfaces with different surface patterns. Superhydrophobic microcavity surfaces were fabricated in silicon and coated with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS). For the more irregular surface patterns, the observed increase in roll...

  14. Modelling of Ionospheric Irregularities and Total Electron Content.

    Science.gov (United States)

    1983-12-01

    heating and their Isle stital filtering effet fteAeioatnao aa effects on transitinospherte propagation. Pro,’dnso ips~ obse-vations of the temporal...irregularities at different heights. Radio Phys. Quantum Electron-. Lngl. Transl.. 20. 1246. 1977. S) tfttu-uatiolis. It serrs . ho%&ever thait ;to outer

  15. Predictions of Stellar Occultations by Irregular Satellites up to 2020

    Science.gov (United States)

    Ramos Gomes, Altair; Assafin, Marcelo; Beauvalet, Laurene; Desmars, Josselin; Vieira-Martins, Roberto; Camargo, Julio I.; Morgado, Bruno Eduardo; Braga Ribas, Felipe

    2017-06-01

    Due to their orbital configurations, it is believed the irregular satellites of the Giant Planets were captured by their host planets during the Solar System evolution. It is important to know their physical parameters such as size, shape, albedo and composition in an attempt to access their origin. The best ground-based technique to do so is by stellar occultations.With the release of the GAIA catalog and the publication of a large database of positions of irregular satellites (Gomes-Júnior et al., 2015), the position of the stars and the ephemeris of the satellites are improved to better predict stellar occultation.The present work predicts such events for the 8 largest irregular satellites of Jupiter and the largest irregular satellite of Saturn, Phoebe, up to 2020. Another motivation is the passage of Jupiter in front of the Galatic Plane in 2019-2020 increasing a lot the number of stars to be occulted. The same happens with Saturn in 2018.

  16. An Analysis of the Incidence of Recruiter Irregularities

    Science.gov (United States)

    2010-01-01

    provided data and answered our questions about the incidence of recruiter irregularities. The people are Ted Disney at the U.S. Army Recruiting...are more likely to ultimately be substantiated. The Army and the Navy, in contrast, have fairly expansive inter- nal reporting requirements that

  17. Active Absorption of Irregular Gravity Waves in BEM-Models

    DEFF Research Database (Denmark)

    Brorsen, Michael; Frigaard, Peter

    1992-01-01

    The boundary element method is applied to the computation of irregular gravity waves. The boundary conditions at the open boundaries are obtained by a digital filtering technique, where the surface elevations in front of the open boundary are filtered numerically yielding the velocity...

  18. Wheel-rail interaction at short-wave irregularities

    NARCIS (Netherlands)

    Steenbergen, M.J.M.M.

    2008-01-01

    Short-wave irregularities in the wheel-rail interface are at the basis of track and vehicle damage and deterioration. On the short term, they result into high dynamic train-track interaction forces and a high energy input into the system that must be dissipated in the different system components or

  19. 50 KPC radio trails behind irregular galaxies in A1367

    Science.gov (United States)

    Gavazzi, G.; Jaffe, W.

    1987-11-01

    The authors report the discovery of exceptionally bright and extended trails of radio emission behind three irregular galaxies in the periphery of the cluster A 1367, in the Coma Supercluster. Turbulent interaction with the intergalactic medium or a past catastrophic collision between galaxies could have produced the observed phenomenon.

  20. Modeling irregularly spaced residual series as a continuous stochastic process

    NARCIS (Netherlands)

    Von Asmuth, J.R.; Bierkens, M.F.P.

    2005-01-01

    In this paper, the background and functioning of a simple but effective continuous time approach for modeling irregularly spaced residual series is presented. The basic equations were published earlier by von Asmuth et al. (2002), who used them as part of a continuous time transfer function noise mo

  1. Robust Fusion of Irregularly Sampled Data Using Adaptive Normalized Convolution

    NARCIS (Netherlands)

    Pham, T.Q.; Vliet, L.J. van; Schutte, K.

    2006-01-01

    We present a novel algorithm for image fusion from irregularly sampled data. The method is based on the framework of normalized convolution (NC), in which the local signal is approximated through a projection onto a subspace. The use of polynomial basis functions in this paper makes NC equivalent to

  2. Active Absorption Wave Maker System for Irregular Waves

    Institute of Scientific and Technical Information of China (English)

    柳淑学; 王先涛; 李木国; 郭美谊

    2003-01-01

    The key problem in physical model tests with highly reflective structures is to prevent the multiple reflections between the reflective structures and the wave maker. An active absorption wave maker system is described and the representative frequency method for irregular waves is proposed in this paper. Physical model tests are conducted to verify the effectiveness of the proposed method.

  3. Comparison of correlation analysis techniques for irregularly sampled time series

    Directory of Open Access Journals (Sweden)

    K. Rehfeld

    2011-06-01

    Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

    All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

    We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ18O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

  4. Finding Causes of Irregular Headways Integrating Data Mining and AHP

    Directory of Open Access Journals (Sweden)

    Shi An

    2015-11-01

    Full Text Available Irregular headways could reduce the public transit service level heavily. Finding out the exact causes of irregular headways will greatly help to develop efficient strategies aiming to improve transit service quality. This paper utilizes bus GPS data of Harbin to evaluate the headway performance and proposes a statistical method to identify the abnormal headways. Association mining is used to dig deeper and recognize six causes of bus bunching. The AHP, embedded data analysis, is applied to determine the weight of each cause in the case of that these causes are combined with each other constantly. Results show that the front bus has a greater effect on bus bunching than the following bus, and the traffic condition is the most critical factor affecting bus headway.

  5. Irregular Migration - between legal status and social practices

    DEFF Research Database (Denmark)

    Lund Thomsen, Trine

    2012-01-01

    . Language and religious affiliations of an immigrant adolescent in Norway by Haque, Shahzaman View Top 20 Most Downloaded Articles Previous Article Next Article Go to table of contents Download full text pdf (PDF, 425 KB) Irregular Migration – Between Legal Status and Social Practices Narratives of Polish...... labour migration Thomsen, Trine Lund1 1Centre for the Studies of Migration and Diversity (CoMID), Aalborg University, Denmark Citation Information: Nordic Journal of Migration Research. Volume 2, Issue 4, Pages 308–315, ISSN (Online) 1799-649X, ISSN (Print) , DOI: 10.2478/v10202-012-0001-0, December 2012...... Publication History: Published Online: 2012-12-28 Abstract How do Polish migrant workers experience the process of migration and how does irregular migration status influence their life plans? In this article I analyse how the shifts between different legal statuses may be related to the social practices...

  6. Searching for Strange Attractor in Sliver Irregularity Series

    Institute of Scientific and Technical Information of China (English)

    YAO Jie; ZHONG Zai-min; CHEN Ren-zhe; YE Guo-ming

    2007-01-01

    The chaotic nonlinear time series method isapplied to analyze the sliver irregularity in textileprocessing. Because it unifies the system's determinacy andrandonmess, it seems more adaptive to describe the sliverirregularity than conventional methods. Firstly, the chaoscharacter, i. e. fractal dimension, positive Lyapunovexponent, and state space parameters, including time delayand reconstruction dimension, are calculated respectively.As a result, a positive Lyapunov exponent and a fractaldimension are obtained, which demonstrates that the systemis chaotic in fact. Secondly, both local linear forecast andglobal forecast models based on the reconstructed state areadopted to predict a segment part of the sliver irregularityseries, which proves the validity of this analysis.Therefore, the sliver irregularity series shows the evidenceof chaotic phenomena, and thus laying the theoreticalfoundation for analyzing and modeling the sliver irregularityseries by applying the chaos theory, and providing a newway to understand the complexity of the sliver irregularitymuch better.

  7. An analysis of the timing irregularities for 366 pulsars

    CERN Document Server

    Hobbs, G; Kramer, M

    2009-01-01

    We provide an analysis of timing irregularities observed for 366 pulsars. Observations were obtained using the 76-m Lovell radio telescope at the Jodrell Bank Observatory over the past 36 years. These data sets have allowed us to carry out the first large-scale analysis of pulsar timing noise over time scales of > 10yr, with multiple observing frequencies and for a large sample of pulsars. Our sample includes both normal and recycled pulsars. The timing residuals for the pulsars with the smallest characteristic ages are shown to be dominated by the recovery from glitch events, whereas the timing irregularities seen for older pulsars are quasi-periodic. We emphasise that previous models that explained timing residuals as a low-frequency noise process are not consistent with observation.

  8. Constructing C1 Continuous Surface on Irregular Quad Meshes

    Institute of Scientific and Technical Information of China (English)

    HE Jun; GUO Qiang

    2013-01-01

    A new method is proposed for surface construction on irregular quad meshes as extensions to uniform B-spline surfaces. Given a number of control points, which form a regular or irregular quad mesh, a weight function is constructed for each control point. The weight function is defined on a local domain and is C1 continuous. Then the whole surface is constructed by the weighted combination of all the control points. The property of the new method is that the surface is defined by piecewise C1 bi-cubic rational parametric polynomial with each quad face. It is an extension to uniform B-spline surfaces in the sense that its definition is an analogy of the B-spline surface, and it produces a uniform bi-cubic B-spline surface if the control mesh is a regular quad mesh. Examples produced by the new method are also included.

  9. The scholarly rebellion of the early Baker Street Irregulars

    Directory of Open Access Journals (Sweden)

    George Mills

    2017-03-01

    Full Text Available This work provides and analyzes an early institutional history of the pioneering Sherlock Holmes American fan club, the Baker Street Irregulars (BSI. Using the publications and records of these devoted Sherlockians, I track the BSI's development from a speakeasy gathering in 1934 to a national organization by the mid-1940s. This growth was built on a foundation of Victorian nostalgia and playful humor. Yet at the same time the members of the Irregulars took their fandom seriously, producing Sherlockian scholarship and creating an infrastructure of journals, conferences, and credentialing that directly mimicked the academy. They positioned themselves in contrast to prevailing scholarly practices of the period, such as New Criticism. I trace both how their fan practices developed over time and how this conflict with the academy led to many of the BSI's defining characteristics.

  10. An Amino Acid Code for Irregular and Mixed Protein Packing

    Science.gov (United States)

    Joo, Hyun; Chavan, Archana; Fraga, Keith; Tsai, Jerry

    2015-01-01

    To advance our understanding of protein tertiary structure, the development of the knob-socket model is completed in an analysis of the packing in irregular coil and turn secondary structure packing as well as between mixed secondary structure. The knob-socket model simplifies packing based on repeated patterns of 2 motifs: a 3 residue socket for packing within 2° structure and a 4 residue knob-socket for 3° packing. For coil and turn secondary structure, knob-sockets allow identification of a correlation between amino acid composition and tertiary arrangements in space. Coil contributes almost as much as α-helices to tertiary packing. Irregular secondary structure involves 3 residue cliques of consecutive contacting residues or XYZ sockets. In irregular sockets, Gly, Pro, Asp and Ser are favored, while Cys, His, Met and Trp are not. For irregular knobs, the preference order is Arg, Asp, Pro, Asn, Thr, Leu, and Gly, while Cys, His, Met and Trp are not. In mixed packing, the knob amino acid preferences are a function of the socket that they are packing into, whereas the amino acid composition of the sockets does not depend on the secondary structure of the knob. A unique motif of a coil knob with an XYZ β-sheet socket may potentially function to inhibit β-sheet extension. In addition, analysis of the preferred crossing angles for strands within a β-sheet and mixed α-helices/β-sheets identifies canonical packing patterns useful in protein design. Lastly, the knob-socket model abstracts the complexity of protein tertiary structure into an intuitive packing surface topology map. PMID:26370334

  11. Using Little's Irregularity Index in orthodontics: outdated and inaccurate?

    LENUS (Irish Health Repository)

    Macauley, Donal

    2012-12-01

    Little\\'s Irregularity Index (LII) was devised to objectively score mandibular incisor alignment for epidemiological studies but has been extended to assess the relative performance of orthodontic brackets, retainer or treatment modalities. Our aim was to examine the repeatability and precision of LII measurements of four independent examiners on the maxillary arch of orthodontic patients. The hypothesis was that the reproducibility of individual contact point displacement measurements, used to calculate the LII score, are inappropriate.

  12. New Secular Resonances Involving the Irregular Satellies of Saturn

    Science.gov (United States)

    Cuk, M.; Burns, J. A.; Carruba, V.; Nicholson, P. D.; Jacobson, R. A.

    2002-09-01

    We report that some of the recently found irregular satellites of Saturn, and possibly Uranus, dwell in hitherto unobserved resonances. These include the Kozai resonance, previously postulated but never before found in our Solar System. We also describe a new type of secular resonance for irregular satellites at higher inclinations (40-45o ), which locks the satellite's pericenter with that of the planet. Comparing theoretical predictions (Carruba et al. 2002)with the orbits of those Saturnian irregulars having inclinations around 45o , we found that Saturn's 2000_S5 and 2000_S6 have extremely slow motions of their arguments of pericenter, and their pericenters are presently almost 90 degrees away from their nodes (Jacobson 2001). Longitude of pericenter of another prograde satellite of Saturn, 2000_S3, precesses extremely slowly (Jacobson 2001). We simulated the motion of a clone of 2000_S3 and found that its longitude of pericenter could be librating around that of Saturn, with a very long period (on the order of 30,000 years) and large amplitude (120o ). The nature of this resonance appears different from one affecting certain Jovian moons (Saha and Tremaine 1993). If the amplitude of pericenter librations can be that large, another Saturnian irregular, 2000_S2, could be in a similar resonance. The Uranian retrograde satellites Stephano and Caliban (at inclinations of about 140o ) also have ϖ's that precess very slowly and are roughly aligned with Uranus's (Jacobson 2000). We are currently examining their motion to see if they are also in a resonance similar to that seen at 2000_S3.

  13. Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban

    CERN Document Server

    Maris, M; Cremonese, G; Fulle, M; Maris, Michele; Carraro, Giovanni; Cremonese, Gabriele; Fulle, Marco

    2001-01-01

    We report on accurate BVRI photometry for the two Uranus irregular satellites Sycorax and Caliban. We derive colours, showing that Sycorax is bluer than Caliban. Our data allows us to detect a significant variability in the Caliban's light-curve, which suggests an estimated period of about 3 hours. Despite it is the brighter of the two bodies, Sycorax does not display a strong statistically significant variability. However our data seem to suggest a period of about 4 hours

  14. Generalizing Lifted Tensor-Product Wavelets to Irregular Polygonal Domains

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, M.; Duchaineau, M.A.; Hamann, B.; Joy, K.I.

    2002-04-11

    We present a new construction approach for symmetric lifted B-spline wavelets on irregular polygonal control meshes defining two-manifold topologies. Polygonal control meshes are recursively refined by stationary subdivision rules and converge to piecewise polynomial limit surfaces. At every subdivision level, our wavelet transforms provide an efficient way to add geometric details that are expanded from wavelet coefficients. Both wavelet decomposition and reconstruction operations are based on local lifting steps and have linear-time complexity.

  15. Irregular and adaptive sampling for automatic geophysic measure systems

    Science.gov (United States)

    Avagnina, Davide; Lo Presti, Letizia; Mulassano, Paolo

    2000-07-01

    In this paper a sampling method, based on an irregular and adaptive strategy, is described. It can be used as automatic guide for rovers designed to explore terrestrial and planetary environments. Starting from the hypothesis that a explorative vehicle is equipped with a payload able to acquire measurements of interesting quantities, the method is able to detect objects of interest from measured points and to realize an adaptive sampling, while badly describing the not interesting background.

  16. Photometry of Irregular Satellites of Uranus and Neptune

    Science.gov (United States)

    Grav, Tommy; Holman, Matthew J.; Fraser, Wesley C.

    2004-09-01

    We present BVR photometric colors of six Uranian and two Neptunian irregular satellites, collected using the Magellan Observatory (Las Campanas, Chile) and the Keck Observatory (Manua Kea, Hawaii). The colors range from neutral to light red, and like the Jovian and the Saturnian irregular satellites (Grav et al.) there is an apparent lack of the extremely red objects found among the Centaurs and Kuiper Belt objects. The Uranian irregular satellites can be divided into three possible dynamical families, but the colors collected show that two of these dynamical families, the Caliban and Sycorax clusters, have heterogeneous colors. Of the third possible family, the 168° cluster containing two objects with similar average inclinations but quite different average semimajor axes, only one object (U XXI Trinculo) was observed. The heterogeneous colors and the large dispersion of the average orbital elements lead us to doubt that they are collisional families. We favor single captures as a more likely scenario. The two Neptunian satellites observed (N II Nereid and S/2002 N1) both have very similar neutral, Sun-like colors. Together with the high collisional probability between these two objects over the age of the solar system (Nesvorný et al.; Holman et al.), this suggests that S/2002 N1 is a fragment of Nereid, broken loose during a collision or cratering event with an undetermined impactor.

  17. Flow induced vibrations in arrays of irregularly spaced cylinders

    Science.gov (United States)

    Taub, Gordon; Michelin, Sébastien

    2014-11-01

    Historically the main industrial applications of cylinder arrays in cross flows favored regular arrangements of cylinders. For this reason, most past studies of Flow Induced Vibrations (FIV) in large cylinder arrays have focused on such arrangements. Recently there has been some interest in generating renewable energy using FIV of bluff bodies. In such applications it will likely be beneficial to enhance, rather than suppress FIV. It is not known a priori if regular or irregularly spaced arrays are most adequate for this type of application. In this study, wind tunnel experiments were conducted on one regularly spaced array and four different irregularly spaced arrays of cylinders in a cross flow. Each arrangement of cylinders was examined under eight different orientations to a cross flow ranging between 10 m/s and 17 m/s. The average amplitude of vibration of the cylinders was found to highly depend on arrangement and orientation. The typical amplitude of vibration of the rods in the irregular arrangements were found to be an order of magnitude larger than that of the regular array. A simple model was proposed in order to predict if a given arrangement was likely to produce large oscillations, and the validity of the model was examined. This research was supported by a Marie Curie International Reintegration Grant within the 7th European Community Framework Program (Grant PIRG08-GA-2010-276762).

  18. Histogram Planimetry Method for the Measurement of Irregular Wounds.

    Science.gov (United States)

    Yesiloglu, Nebil; Yildiz, Kemalettin; Cem Akpinar, Ali; Gorgulu, Tahsin; Sirinoglu, Hakan; Ozcan, Arzu

    2016-09-01

    Irregularly shaped wounds or flap borders usually require specified software or devices to measure their area and follow-up wound healing. In this study, an easy way of area measurement called histogram planimetry (HP) for wounds with irregular geometric shapes is defined and compared to conventional millimetric wound measurement. Ten irregularly bordered geometric shapes were measured by 4 different individuals working as surgical assistants using both HP and manual millimetric measurement tools. The amount of time for each wound shape calculation as well as the measurements of the wound areas were noted. All measurements were compared for each method and between each individual using the Wilcoxon signed-rank test. There was no statistically significant difference between 2 measurement methods by means of measured areas; however, measurement time was significantly lower when the HP method was used. There also was no significant difference between the individuals' measurements and calculation times. These results indicated that HP is useful as a conventional millimetric square wound measurement technique with significantly lower measurement times. Due to the development of photo-editor software technologies, measurements in the surgical field have become more accurate and rapid than conventional manual methods without consuming the time and energy needed for other studies. A future study including comparisons between the presented method and complex computerized measurement methods, in terms of duration and accuracy, may provide additional supportive data for the authors' method.

  19. Using a Calculated Pulse Rate with an Artificial Neural Network to Detect Irregular Interbeats.

    Science.gov (United States)

    Yeh, Bih-Chyun; Lin, Wen-Piao

    2016-03-01

    Heart rate is an important clinical measure that is often used in pathological diagnosis and prognosis. Valid detection of irregular heartbeats is crucial in the clinical practice. We propose an artificial neural network using the calculated pulse rate to detect irregular interbeats. The proposed system measures the calculated pulse rate to determine an "irregular interbeat on" or "irregular interbeat off" event. If an irregular interbeat is detected, the proposed system produces a danger warning, which is helpful for clinicians. If a non-irregular interbeat is detected, the proposed system displays the calculated pulse rate. We include a flow chart of the proposed software. In an experiment, we measure the calculated pulse rates and achieve an error percentage of pulse rates to detect irregular interbeats, we find such irregular interbeats in eight participants.

  20. Transnational activities and aspirations of irregular migrants in Belgium and the Netherlands

    NARCIS (Netherlands)

    M.J. van Meeteren (Masja)

    2012-01-01

    textabstractThe literature on immigrant transnationalism and on irregular immigration suggests irregular migrants engage relatively little in transnational activities because of the obstacles associated with their legal and economic statuses. Drawing on participant observation and in-depth interview

  1. Shadow Places: Patterns of Spatial Concentration and Incorporation of Irregular Immigrants in the Netherlands

    NARCIS (Netherlands)

    A.S. Leerkes (Arjen); G.B.M. Engbersen (Godfried); M.R.P.J.R.S. van San (Marion)

    2007-01-01

    textabstractSummary: In Western countries, irregular immigrants constitute a sizeable segment of the population. By combining quantitative and qualitative research methods, this article describes and explains irregular immigrants’ patterns of spatial concentration and incorporation in the Netherland

  2. Counting forbidden patterns in irregularly sampled time series. II. Reliability in the presence of highly irregular sampling

    Science.gov (United States)

    Sakellariou, Konstantinos; McCullough, Michael; Stemler, Thomas; Small, Michael

    2016-12-01

    We are motivated by real-world data that exhibit severe sampling irregularities such as geological or paleoclimate measurements. Counting forbidden patterns has been shown to be a powerful tool towards the detection of determinism in noisy time series. They constitute a set of ordinal symbolic patterns that cannot be realised in time series generated by deterministic systems. The reliability of the estimator of the relative count of forbidden patterns from irregularly sampled data has been explored in two recent studies. In this paper, we explore highly irregular sampling frequency schemes. Using numerically generated data, we examine the reliability of the estimator when the sampling period has been drawn from exponential, Pareto and Gamma distributions of varying skewness. Our investigations demonstrate that some statistical properties of the sampling distribution are useful heuristics for assessing the estimator's reliability. We find that sampling in the presence of large chronological gaps can still yield relatively accurate estimates as long as the time series contains sufficiently many densely sampled areas. Furthermore, we show that the reliability of the estimator of forbidden patterns is poor when there is a high number of sampling intervals, which are larger than a typical correlation time of the underlying system.

  3. Optimización de la distribución de piezas irregulares en chapas // Irregular parts nesting problem optimization.

    Directory of Open Access Journals (Sweden)

    A. M. Lastres - Aleaga

    2010-05-01

    Full Text Available ResumenEn el presente artículo se realiza un estudio de diferentes esquemas de solución reflejados en laliteratura, que tratan el problema de la distribución de piezas irregulares en superficies planas conanidamiento bidimensional (Nesting. Fueron analizados diferentes esquemas de solución, siendolos que consideran la geometría real de la pieza, durante la evaluación y posicionamiento de lasmismas sobre la superficie a cortar, los que garantizan el mayor aprovechamiento del material. Elesquema propuesto se caracteriza por un tratamiento gráfico de las piezas que permite acelerar elproceso de reconocimiento y evaluación de opciones de acoplamiento entre ellas, así como lacreación de poblaciones de conglomerados crecientes para su ubicación definitiva en la superficie acortar. En la generación de poblaciones de opciones de solución, se utiliza un algoritmo derivado delmétodo de Integración de Variables, además se realiza la comparación de los resultados obtenidospor el método propuesto, con otros resultados generados por procedimientos desarrollados pordiferentes autores, alcanzando mejorar los valores de aprovechamiento de material y la reduccióndel tiempo de generación de soluciones.Palabras claves: Distribución de piezas irregulares en superficies; optimización; Métodos Evolutivos;_________________________________________________________________________AbstractIn this article, we study various solution schemes reported in the literature, which deal with theproblem of irregular parts distribution on flat surfaces with two-dimensional nesting. Different solutionschemes were analyzed, which they consider to be the real geometry of the part, during theevaluation and positioning them on the surface to be cut, ensuring the best use of the material. Theproposed scheme is characterized by a graphic treatment of the pieces that can accelerate theprocess of recognition and evaluation of options coupling between them, as well as

  4. [Irregular secretion of prolactin in infertile women with normoprolactinemic galactorrhea].

    Science.gov (United States)

    Villanueva Díaz, Carlos A; Echavarria Sánchez, Mirna; Juárez Bengoa, Armando

    2007-02-01

    Abnormal frequency and pulse amplitud of prolactin secretion in micro and macroprolactinomas has been atributed to a dysfunctional tumoral lactotrope. Previous evidence suggests that non tumoral hyperprolactinemia is caused by a hypothalamic dysfunction. The regularity of prolactin secretion has not been studied with cuantitative methods in patients with normoprolactinemic galactorrhea (NPG) which could be considered an entity that precedes non tumoral and tumoral hyperprolactinemia. To analyze the 24-hour prolactin secretion pattern and its secretion regularity in a group of infertile women with normoprolactinemic galatorea. A transversal-comparative study was carried out in 6 infertile women with normoprolactinemic galactorrhea and 4 healthy women as controls. The 24 hour prolactin profile, the ratio night time mean concentration/daytime mean concentrattion (NM/DM ratio) and apparent entropy (Ap En, Ap En ratio) were compared in the two groups. Blunting of the nyctohemeral rythm and nocturn hyperprolactinaemia occurred in patients with normoprolactinemic galactorrhea (NPG). NM/DM ratio was lower in patients with NPG than in controls (1.28 +/- 0.25 vs. 1.75 +/- 0.05; p= 0.01). Higher irregularity of prolactin secretion was found in patients with NPG (ApEn: 0.853 +/- 0.158 vs 0.608 +/- 0.171, p=0.04; Ap En ratio: 0.839 +/- 0.11 vs 0.661 +/- 0.14; p=0.04). The irregularity of prolactin secretion in patients with NPG is not dependant on the presence of a pituitary tumour which suggests that a hypothalamic dysfunction underlies this condition. An irregular secretion and a higher daily mass production of prolactin in patients with NPG could explain both galactorrhea and infertility.

  5. The sunspot cycle and ``auroral'' F layer irregularities

    Science.gov (United States)

    Aarons, J.; Kersley, L.; Rodger, A. S.

    The use of the word ``aurora'' for many different observations at high latitudes has limited the concepts involved; this is particularly true for F region irregularities. Observations setting the position of the auroral oval (Starkov and Fel'dshtein, 1970) were made using primarily the 555.7-nm green line, which is emitted predominantly at E layer heights. These observations have shown that the change in position of the auroral oval for low values of Kp as a function of sunspot cycle is of the order of 1° to 2° between sunspot maximum and sunspot minimum. However, irregularities in the F region show much larger solar cycle variations in the locations of the equatorward boundary, typically 10°. A review of scintillation data indicates that at a given auroral latitude, the scintillation activity increases with sunspot number. In addition, for a constant scintillation intensity, the equatorward boundary moves to lower latitudes as sunspot maximum is approached. We review existing spread F studies and show that for quiet geomagnetic conductions, there is lower occurrence during years of low sunspot numbers than during years of high sunspot numbers. However, the spread F index, related to Δ f/f0F2, is higher during years of low sunspot number than during years of high sunspot number. We demonstrate that this apparent dichotomy can be reconciled by using a new method of normalizing the spread F index by the maximum electron concentration of the F layer. We briefly discuss the possible explanations for the observed solar cycle variations of irregularity occurrence in terms of the absolute values and gradients of electron concentration and the E region conductivity.

  6. Irregular breakfast eating and health status among adolescents in Taiwan

    Directory of Open Access Journals (Sweden)

    Hsieh Yeu-Sheng

    2006-12-01

    Full Text Available Abstract Background Regular breakfast eating (RBE is an important contributor to a healthy lifestyle and health status. The aims of the present study were to evaluate the relationships among irregular breakfast eating (IRBE, health status, and health promoting behavior (HPB for Taiwanese adolescents. Methods A cross-sectional, descriptive design was used to investigate a cluster sample of 1609 (7th -12th grade adolescents located in the metropolitan Tao-Yuan area during the 2005 academic year. The main variables comprised breakfast eating pattern, body weight, and health promoting behaviors. Data were collected by a self-administered questionnaire. Results A total of 1609 participants were studied, 64.1% in junior high school and 35.9% in high school, boys (47.1% and girls (52.9% ranging in age from 12–20 years. Of the total participant population, 28.8% were overweight and nearly one quarter (23.6% reported eating breakfast irregularly during schooldays. The findings indicated that adolescents with RBE had a lower risk of overweight (OR for IRBE vs. RBE = 1.51, 95% CI: 1.12, 2.04, and that the odds of becoming overweight were 51% greater for IRBE than for RBE even after controlling for demographical and HPB variables. IRBE also was a strong indicator for HPB. However, the profile of the high-risk IRBE group was predominantly junior high schoolchildren and/or children living without both parents. Conclusion This study provides valuable information about irregular breakfast eating among adolescents, which is associated with being overweight and with a low frequency of health promoting behavior. School and family health promotion strategies should be used to encourage all adolescents to eat breakfast regularly.

  7. Similarity estimators for irregular and age-uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  8. Similarity estimators for irregular and age uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  9. Reducing Inconsistent Rules Based on Irregular Decision Table

    Institute of Scientific and Technical Information of China (English)

    兰轶东; 张霖; 刘连臣

    2004-01-01

    In this paper, we study the problem of rule extraction from data sets using the rough set method. For inconsistent rules due to improper selection of split-points during discretization, and/or to lack of information, we propose two methods to remove their inconsistency based on irregular decision tables.By using these methods, inconsistent rules are eliminated as far as possible, without affecting the remaining consistent rules. Experimental test indicates that use of the new method leads to an improvement in the mean accuracy of the extracted rules.

  10. Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban

    Science.gov (United States)

    Maris, Michele; Carraro, Giovanni; Cremonese, Gabriele; Fulle, Marco

    2001-05-01

    We report on accurate BVRI photometry for the two Uranian irregular satellites Sycorax and Caliban. We derive colors showing that Sycorax is bluer than Caliban. Our data allow us to detect a significant variability in Caliban's light curve, which suggests an estimated period of about 3 hr. Although it is the brighter of the two bodies, Sycorax does not display a strong, statistically significant variability. However, our data seem to suggest a period of about 4 hr. Based on observations carried out at ESO La Silla (Chile). See the Asteroid Properties Database (1993), http://pdssbn.astro.umd.edu/sbnhtml/.

  11. Favelas y fraccionamientos irregulares en São Paulo1

    OpenAIRE

    Silva, Helena Menna Barreto; Ceneviva, Laura Vieira

    2013-01-01

    INTRODUCCIÓN: EL VIRAJE DE LOS AÑOS SETENTA Para las poblaciones de escasos recursos de São Paulo, la ocupación de terrenos en las favelas y en los fraccionamientos irregulares, o el arrendamiento de cuartos en los inmuebles deteriorados de la zona urbanizada (cortiços), constituyen desde hace varias décadas la única posibilidad de acceso a la vivienda. Hacia mediados de los años setenta, la situación alcanzó un nivel crítico. Para los cientos de miles de habitantes que habían adquirido terre...

  12. Mapa MEGNO para satélites irregulares de Satuno

    Science.gov (United States)

    Moyano, M. M.; Leiva, A. M.

    By implementing the elliptic restricted three-body model we obtain high resolution dynamical maps in the phase space region corresponding to that where Saturn's irregular satellites are currently found. The nature of the trajectories is characterized by the MEGNO chaos indicator (Cincotta P. and Simó C., 2000), which allows to identify regions of chaotic and quasi- periodic trajectories much faster than with other indicators (e.g. Lyapunov exponents). The results obtained allow to identify with great detail the boundaries of the regions of regular motion, chaotic motion, and substruc- tures associated to mean motion resonances. FULL TEXT IN SPANISH

  13. El derecho al trabajo y los extranjeros irregulares

    OpenAIRE

    2010-01-01

    El artículo analiza desde una perspectiva de derecho constitucional la situación en España de los trabajadores extranjeros irregulares, defiende que estos poseen un derecho al trabajo de rango constitucional e intenta delimitar el contenido de este derecho en relación al derecho al trabajo del que son titulares los españoles. Plantea como conclusión que el contenido de dicho derecho no tiene porqué coincidir con el de los españoles. De hecho, considera que difiere del de est...

  14. Irregular subharmonic cluster patterns in an autonomous photoelectrochemical oscillator.

    Science.gov (United States)

    Miethe, Iljana; García-Morales, Vladimir; Krischer, Katharina

    2009-05-15

    Unusual subharmonic cluster patterns are observed during the oscillatory electro-oxidation of n-Si(111) under illumination. 2D in situ imaging of the electrode by means of an ellipsometric setup allows local variations in the oxide layer thickness to be monitored. The local oscillators exhibit an irregular distribution of the amplitude with the extrema locked to the constant base frequency of the total current. In addition, Ising 2-phase clustering occurs at half the base frequency. This intrinsic dynamics is described by means of a modified complex Ginzburg-Landau equation.

  15. TCM Treatment for Gynaecological Diseases-Irregular Menstruation

    Institute of Scientific and Technical Information of China (English)

    Engin CAN

    2008-01-01

    @@ Menstruation is the periodic shedding(usually monthly)of the lining of the womb.Generally speaking,menstruation starts during puberty around 10-16 years old and continues until the menopause about 45-55 years old.An average menstrual cycle is about 28 days,but it may vary between 24-35 days.According to a study most women have more than 500 periods in a lifetime.Any abnormality of the above menstrual conditins can be regarded as irregular.

  16. Similarity estimators for irregular and age uncertain time series

    Directory of Open Access Journals (Sweden)

    K. Rehfeld

    2013-09-01

    Full Text Available Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011 and mutual information (gMI, Rehfeld et al., 2013 against their interpolation-based counterparts and the new event synchronization function (ESF. We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60–55% (in the linear case to 53–42% (for the nonlinear processes of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time

  17. In situ measurements of plasma irregularity growth in the cusp ionosphere

    Science.gov (United States)

    Oksavik, K.; Moen, J.; Lester, M.; Bekkeng, T. A.; Bekkeng, J. K.

    2012-11-01

    The Investigation of Cusp Irregularities (ICI-2) sounding rocket was launched on 5 December 2008 from Ny-Ålesund, Svalbard. The high-resolution rocket data are combined with data from an all-sky camera, the EISCAT Svalbard Radar, and the SuperDARN Hankasalmi radar. These data sets are used to characterize the spatial structure of F region irregularities in the dayside cusp region. We use the data set to test two key mechanisms for irregularity growth; the Kelvin-Helmholtz (KH) and gradient drift (GD) instabilities. Except for a promising interval of 4-6 km irregularities, the KH growth rate was found to be too slow to explain the observed plasma irregularities. The time history of the plasma gives further support that structured particle precipitation could be an important source of kilometer- to hectometer-scale “seed” irregularities, which are then efficiently broken down into decameter-scale irregularities by the GD mechanism.

  18. Human Rights of Irregular Immigrants: A Challenge for the Universality of Human Rights

    Directory of Open Access Journals (Sweden)

    Luljeta Ikonomi

    2013-07-01

    Full Text Available Irregular immigration is a phenomenon with a substantial impact for the majority of the countries. The paper analyses whether there is an adequate human rights framework for protection of irregular immigrants or whether the irregular status exempts the migrants from the protection of international human rights law. If this is the case, then the human rights universality has failed. The paper takes into consideration the developments in the International and EU Law, as well as in the jurisprudence of the international tribunals regarding protection of irregular immigrants. It is divided into three main sections. The first section informs briefly on the dynamics of irregular immigrants; the second section analyses the legislation on irregular immigration from the perspective of the state sovereignty, the third section analyses the human rights law and the protection it affords to irregular immigrants, pursuant to the interpretation of International tribunals.

  19. Irregular Information of the Rainstorm in a Continuous Rainy Weather

    Institute of Scientific and Technical Information of China (English)

    LI; Ming-juan

    2012-01-01

    [Objective]The research aimed to analyze irregular information of the local rainstorm process (during 5-6 September,2009) in autumn continuous rainy weather in north Shaanxi. [Method] Based on V-3θ chart, routine observation data provided by Micaps system, satellite cloud chart and data at 100 automatic meteorological stations of Shaanxi, for rainstorm process in autumn continuous rainy weather in north Shaanxi during 4-10 September, 2009, by using structure analysis method, irregular information in local rainstorm weather was analyzed. [Result]In whole precipitation process, atmospheric structure in rainstorm zone presented obvious evolution process. Before precipitation, typical atmospheric structure information of the sudden convective weather appeared. Obvious ultra-low temperature structure appeared at 200 hPa, and consistent clockwise rotation flow was at vertical wind field. Meanwhile, water vapor was sufficient, and unstable energy existed at low layer. Structure characteristic of the convective strong precipitation appeared by advancing for 12h. As precipitation weakened, unstable energy was released, and ultra-low temperature disappeared. [Conclusion]The research provided some thoughts for the forecast of such weather process.

  20. Using Radio Irregularity for Increasing Residential Energy Awareness

    Directory of Open Access Journals (Sweden)

    A. Miljković

    2012-06-01

    Full Text Available Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration.

  1. Buckling analysis of partially corroded steel plates with irregular surfaces

    Indian Academy of Sciences (India)

    Ahmad Rahbar-Ranji

    2014-04-01

    Corrosion is a long-term, inevitable process, lessens the thickness and load carrying capacity of structures. Old steel structures are more vulnerable to buckling, yielding and fracture due to corrosion. In lieu of a detailed analysis, average thickness assumption is employed for general type of corrosion. However, the estimation of load carrying capacity reduction of corroded structures typically need a much higher level of accuracy, since the actual corroded plates would have irregular surfaces. The objective of this article is to determine the effect of general corrosion on reduction of elastic buckling strength of both-sided partially corroded plates with irregular surfaces. Eigenvalue analysis using finite element method is employed for Euler stress calculation of corroded plates. The effects of different influential parameters are investigated and it is found that, aspect ratio of plate, location of corroded area, standard deviation of thickness diminution and concentration of corrosion have influence on reduction of elastic buckling strength. Reduction of elastic buckling strength is very sensitive to the amount of corrosion loss. The higher the amount of corrosion loss, the more reduction of elastic buckling strength.

  2. Unsteady magnetohydrodynamic blood flow through irregular multi-stenosed arteries.

    Science.gov (United States)

    Mustapha, Norzieha; Amin, Norsarahaida; Chakravarty, Santabrata; Mandal, Prashanta Kumar

    2009-10-01

    Flow of an electrically conducting fluid characterizing blood through the arteries having irregular shaped multi-stenoses in the environment of a uniform transverse magnetic-field is analysed. The flow is considered to be axisymmetric with an outline of the irregular stenoses obtained from a three-dimensional casting of a mild stenosed artery, so that the physical problem becomes more realistic from the physiological point of view. The marker and cell (MAC) and successive-over-relaxation (SOR) methods are respectively used to solve the governing unsteady magnetohydrodynamic (MHD) equations and pressure-Poisson equation quantitatively and to observe the flow separation. The results obtained show that the flow separates mostly towards the downstream of the multi-stenoses. However, the flow separation region keeps on shrinking with the increasing intensity of the magnetic-field which completely disappears with sufficiently large value of the Hartmann number. The present observations certainly have some clinical implications relating to magnetotherapy which help reducing the complex flow separation zones causing flow disorder leading to the formation and progression of the arterial diseases.

  3. Hydrophobic pulses predict transmembrane helix irregularities and channel transmembrane units

    Directory of Open Access Journals (Sweden)

    Claustres Mireille

    2011-05-01

    Full Text Available Abstract Background Few high-resolution structures of integral membranes proteins are available, as crystallization of such proteins needs yet to overcome too many technical limitations. Nevertheless, prediction of their transmembrane (TM structure by bioinformatics tools provides interesting insights on the topology of these proteins. Methods We describe here how to extract new information from the analysis of hydrophobicity variations or hydrophobic pulses (HPulses in the sequence of integral membrane proteins using the Hydrophobic Pulse Predictor, a new tool we developed for this purpose. To analyze the primary sequence of 70 integral membrane proteins we defined two levels of analysis: G1-HPulses for sliding windows of n = 2 to 6 and G2-HPulses for sliding windows of n = 12 to 16. Results The G2-HPulse analysis of 541 transmembrane helices allowed the definition of the new concept of transmembrane unit (TMU that groups together transmembrane helices and segments with potential adjacent structures. In addition, the G1-HPulse analysis identified helix irregularities that corresponded to kinks, partial helices or unannotated structural events. These irregularities could represent key dynamic elements that are alternatively activated depending on the channel status as illustrated by the crystal structures of the lactose permease in different conformations. Conclusions Our results open a new way in the understanding of transmembrane secondary structures: hydrophobicity through hydrophobic pulses strongly impacts on such embedded structures and is not confined to define the transmembrane status of amino acids.

  4. 3D Reconstruction of Irregular Buildings and Buddha Statues

    Science.gov (United States)

    Zhang, K.; Li, M.-j.

    2014-04-01

    Three-dimensional laser scanning could acquire object's surface data quickly and accurately. However, the post-processing of point cloud is not perfect and could be improved. Based on the study of 3D laser scanning technology, this paper describes the details of solutions to modelling irregular ancient buildings and Buddha statues in Jinshan Temple, which aiming at data acquisition, modelling and texture mapping, etc. In order to modelling irregular ancient buildings effectively, the structure of each building is extracted manually by point cloud and the textures are mapped by the software of 3ds Max. The methods clearly combine 3D laser scanning technology with traditional modelling methods, and greatly improves the efficiency and accuracy of the ancient buildings restored. On the other hand, the main idea of modelling statues is regarded as modelling objects in reverse engineering. The digital model of statues obtained is not just vivid, but also accurate in the field of surveying and mapping. On this basis, a 3D scene of Jinshan Temple is reconstructed, which proves the validity of the solutions.

  5. An Irregular Wave Maker of Active Absorption with VOF Method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A numerical irregular wave flume with active absorption of re-reflected waves is simulated by use of volume of fluid (VOF) method. An active absorbing wave-maker based on linear wave-theory is set on the left boundary of the wave flume. The progressive waves and the absorbing waves are generated simultaneously at the active wave generating-absorbing boundary. The absorbing waves are generated to eliminate the waves coming back to the generating boundary due to reflection from the outflow boundary and the structures. SIRW method proposed by Frigaard and Brorsen (1995) is used to separate the incident waves and reflected waves. The digital filters are designed based on the surface elevation signals of the two wave gauges. The corrected velocity of the wave-maker paddle is the output from the digital filter in real time. The numerical results of regular and irregular waves by the active absorbing-generating boundary are compared with the numerical results by the ordinary generating boundary to verify the performance of the active absorbing generator boundary. The differences between the initial incident waves and the estimated incident waves are analyzed.

  6. Oral breathing: dentomaxillofacial irregularities associated with nasorespiratory and orthopedic dysfunctions.

    Directory of Open Access Journals (Sweden)

    Clotilde de la Caridad Mora Pérez

    2009-04-01

    Full Text Available Background: Human beings are conditioned to breathe through the nose and feed through the mouth, when this physiological mechanism is interrupted facial and general growth is also affected. Objective: To characterize Angle´s Class II malocclusions in oral breathers with nasorespiratory and orthopedic dysfunctions. Method: A correlational, observational and descriptive study was developed from December 2004 to November 2005 including clinical examination of 833 children out of which 60 were selected to take part in this study. Each case was analyzed in Orthodontia, Orthopedics and Otolaryngology consultations. The studied variables were: age, sex, nasorespiratory disorders, orthopedic dysfunctions, dental-maxillofacial irregularities. Results: The mot frequent dental-maxillofacial irregularities were: bilabial incompetence, transversal micrognathism, vestibular version, overjet and overbite. The most important nasorespiratory dysfunctions found in these children were adenoiditis, and tonsil hypertrophy. The most outstanding orthopedic dysfunction was ciphosis. Conclusion: It is conclusive to state that there is a high relationship between dentomaxillofacial anomalies and nasorespiratory and orthopedic dysfunctions.

  7. Scatter dose summation for irregular fields: speed and accuracy study.

    Science.gov (United States)

    DeWyngaert, J K; Siddon, R L; Bjarngard, B E

    1986-05-01

    Using program IRREG as a standard, we have compared speed and accuracy of several algorithms that calculate the scatter dose in an irregular field. All the algorithms, in some manner, decompose the irregular field into component triangles and obtain the scatter dose as the sum of the contributions from those triangles. Two of the algorithms replace each such component triangle with a sector of a certain "effective radius": in one case the average radius of the triangle, in the other the radius of the sector having the same area as the component triangle. A third algorithm decomposes each triangle further into two right triangles and utilizes the precalculated "equivalent radius" of each, to find the scatter contribution. For points near the center of a square field, all the methods compare favorably in accuracy to program IRREG, with less than a 1% error in total dose and with approximately a factor of 3-5 savings in computation time. Even for extreme rectangular fields (2 cm X 30 cm), the methods using the average radius and the equivalent right triangles agree to within 2% in total dose and approximately a factor of 3-4 savings in computation time.

  8. Reconstruction of Multidimensional Signals from Irregular Noisy Samples

    CERN Document Server

    Nordio, A; Viterbo, E

    2008-01-01

    We focus on a multidimensional field with uncorrelated spectrum, and study the quality of the reconstructed signal when the field samples are irregularly spaced and affected by independent and identically distributed noise. More specifically, we apply linear reconstruction techniques and take the mean square error (MSE) of the field estimate as a metric to evaluate the signal reconstruction quality. We find that the MSE analysis could be carried out by using the closed-form expression of the eigenvalue distribution of the matrix representing the sampling system. Unfortunately, such distribution is still unknown. Thus, we first derive a closed-form expression of the distribution moments, and we find that the eigenvalue distribution tends to the Marcenko-Pastur distribution as the field dimension goes to infinity. Finally, by using our approach, we derive a tight approximation to the MSE of the reconstructed field.

  9. Evaluation of Surface Slope Irregularity in Linear Parabolic Solar Collectors

    Directory of Open Access Journals (Sweden)

    F. Francini

    2012-01-01

    Full Text Available The paper describes a methodology, very simple in its application, for measuring surface irregularities of linear parabolic collectors. This technique was principally developed to be applied in cases where it is difficult to use cumbersome instruments and to facilitate logistic management. The instruments to be employed are a digital camera and a grating. If the reflector surface is defective, the image of the grating, reflected on the solar collector, appears distorted. Analyzing the reflected image, we can obtain the local slope of the defective surface. These profilometric tests are useful to identify and monitor the mirror portions under mechanical stress and to estimate the losses caused by the light rays deflected outside the absorber.

  10. The Panchromatic STARBurst IRregular Dwarf Survey (STARBIRDS) Data

    CERN Document Server

    McQuinn, Kristen B W; Skillman, Evan D

    2016-01-01

    Understanding star formation in resolved low mass systems requires the integration of information obtained from observations at different wavelengths. We have combined new and archival multi-wavelength observations on a set of 20 nearby starburst and post-starburst dwarf galaxies to create a data archive of calibrated, homogeneously reduced images. Named the panchromatic "STARBurst IRregular Dwarf Survey" (STARBIRDS) archive, the data are publicly accessible through the Mikulski Archive for Space Telescopes (MAST). This first release of the archive includes images from the Galaxy Evolution Explorer Telescope (GALEX), the Hubble Space Telescope (HST), and the Spitzer Space Telescope (Spitzer) MIPS instrument. The datasets include flux calibrated, background subtracted images, that are registered to the same world coordinate system. Additionally, a set of images are available which are all cropped to match the HST field of view. The GALEX and Spitzer images are available with foreground and background contamina...

  11. Weighted statistical parameters for irregularly sampled time series

    CERN Document Server

    Rimoldini, Lorenzo

    2014-01-01

    Unevenly spaced time series are common in astronomy because of the day-night cycle, weather conditions, dependence on the source position in the sky, allocated telescope time, corrupt measurements, for example, or be inherent to the scanning law of satellites like Hipparcos and the forthcoming Gaia. This paper aims at improving the accuracy of common statistical parameters for the characterization of irregularly sampled signals. The uneven representation of time series, often including clumps of measurements and gaps with no data, can severely disrupt the values of estimators. A weighting scheme adapting to the sampling density and noise level of the signal is formulated. Its application to time series from the Hipparcos periodic catalogue led to significant improvements in the overall accuracy and precision of the estimators with respect to the unweighted counterparts and those weighted by inverse-squared uncertainties. Automated classification procedures employing statistical parameters weighted by the sugg...

  12. A deeper look at the color of Saturnian irregular satellites

    CERN Document Server

    Grav, T

    2006-01-01

    We have performed broadband color photometry of the twelve brightest irregular satellites of Saturn with the goal of understanding their surface composition, as well as their physical relationship. We find that the satellites have a wide variety of different surface colors, from the negative spectral slopes of the two retrograde satellites S IX Phoebe (S'=-2.5+/-0.4 %/100nm) and S XXV Mundilfari (S'=-5.0+/-1.9 %/100nm) to the fairly red slope of S XXII Ijiraq (S'=19.5+/-0.9 %/100nm). We further find that there exist a correlation between dynamical families and spectral slope, with the prograde clusters, the Gallic and Inuit, showing tight clustering in colors among most of their members. The retrograde objects are dynamically and physically more dispersed, but some internal structure is apparent.

  13. Irregular Computations in Fortran – Expression and Implementation Strategies

    Directory of Open Access Journals (Sweden)

    Jan F. Prins

    1999-01-01

    Full Text Available Modern dialects of Fortran enjoy wide use and good support on high‐performance computers as performance‐oriented programming languages. By providing the ability to express nested data parallelism, modern Fortran dialects enable irregular computations to be incorporated into existing applications with minimal rewriting and without sacrificing performance within the regular portions of the application. Since performance of nested data‐parallel computation is unpredictable and often poor using current compilers, we investigate threading and flattening, two source‐to‐source transformation techniques that can improve performance and performance stability. For experimental validation of these techniques, we explore nested data‐parallel implementations of the sparse matrix‐vector product and the Barnes–Hut n‐body algorithm by hand‐coding thread‐based (using OpenMP directives and flattening‐based versions of these algorithms and evaluating their performance on an SGI Origin 2000 and an NEC SX‐4, two shared‐memory machines.

  14. Towards intrinsic magnetism of graphene sheets with irregular zigzag edges.

    Science.gov (United States)

    Chen, Lianlian; Guo, Liwei; Li, Zhilin; Zhang, Han; Lin, Jingjing; Huang, Jiao; Jin, Shifeng; Chen, Xiaolong

    2013-01-01

    The magnetism of graphene has remained divergent and controversial due to absence of reliable experimental results. Here we show the intrinsic magnetism of graphene edge states revealed based on unidirectional aligned graphene sheets derived from completely carbonized SiC crystals. It is found that ferromagnetism, antiferromagnetism and diamagnetism along with a probable superconductivity exist in the graphene with irregular zigzag edges. A phase diagram is constructed to show the evolution of the magnetism. The ferromagnetic ordering curie-temperature of the fundamental magnetic order unit (FMOU) is 820 ± 80 K. The antiferromagnetic ordering Neel temperature of the FMOUs belonging to different sublattices is about 54 ± 2 K. The diamagnetism is similar to that of graphite and can be well described by the Kotosonov's equation. Our experimental results provide new evidences to clarify the controversial experimental phenomena observed in graphene and contribute to a deeper insight into the nature of magnetism in graphene based system.

  15. Irregular Coarse-Grain Data Parallelism under LPARX

    Directory of Open Access Journals (Sweden)

    Scott R. Kohn

    1996-01-01

    Full Text Available LPARX is a software development tool for implementing dynamic, irregular scientific applications, such as multilevel finite difference and particle methods, on high-performance multiple instruction multiple data (MIMD parallel architectures. It supports coarse-grain data parallelism and gives the application complete control over specifying arbitrary block decompositions. LPARX provides structural abstraction, representing data decompositions as first-class objects that can be manipulated and modified at runtime. LPARX, implemented as a C++ class library, is currently running on diverse MIMD platforms, including the Intel Paragon, Cray C-90, IBM SP2, and networks of workstations running under PVM. Software may be developed and debugged on a singe-processor workstation.

  16. Optimized puncturing distributions for irregular non-binary LDPC codes

    CERN Document Server

    Gorgoglione, Matteo; Declercq, David

    2010-01-01

    In this paper we design non-uniform bit-wise puncturing distributions for irregular non-binary LDPC (NB-LDPC) codes. The puncturing distributions are optimized by minimizing the decoding threshold of the punctured LDPC code, the threshold being computed with a Monte-Carlo implementation of Density Evolution. First, we show that Density Evolution computed with Monte-Carlo simulations provides accurate (very close) and precise (small variance) estimates of NB-LDPC code ensemble thresholds. Based on the proposed method, we analyze several puncturing distributions for regular and semi-regular codes, obtained either by clustering punctured bits, or spreading them over the symbol-nodes of the Tanner graph. Finally, optimized puncturing distributions for non-binary LDPC codes with small maximum degree are presented, which exhibit a gap between 0.2 and 0.5 dB to the channel capacity, for punctured rates varying from 0.5 to 0.9.

  17. Computer-Generated Experimental Designs for Irregular-Shaped Regions

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Nam K.; Piepel, Gregory F.

    2005-09-01

    This paper focuses on the construction of computer-generated designs on irregularly-shaped, constrained regions. Overviews of the Fedorov exchange algorithm (FEA) and other exchange algorithms for the construction of D-optimal designs are given. A faster implementation of the FEA is presented, which is referred to as fast-FEA (denoted FFEA). The FFEA was applied to construct D-optimal designs for several published examples with constrained experimental regions. Designs resulting from the FFEA are more D-efficient than published designs, and provide benchmarks for future comparisons of design construction algorithms. The construction of G-optimal designs for constrained regions is also discussed and illustrated with a published example.

  18. The Orbits of Jupiter’s Irregular Satellites

    Science.gov (United States)

    Brozović, Marina; Jacobson, Robert A.

    2017-04-01

    We report on the improved ephemerides for the irregular Jovian satellites. We used a combination of numerically integrated equations of motion and a weighted least-squares algorithm to fit the astrometric measurements. The orbital fits for 59 satellites are summarized in terms of state vectors, post-fit residuals, and mean orbital elements. The current data set appears to be sensitive to the mass of Himalia, which is constrained to the range of GM = 0.13–0.28 km3 s‑2. Here, GM is the product of the Newtonian constant of gravitation, G and the body's mass, M. Our analysis of the orbital uncertainties indicates that 11 out of 59 satellites are lost owing to short data arcs. The lost satellites hold provisional International Astronomical Union (IAU) designations and will likely need to be rediscovered.

  19. Irregularities of ionospheric VTEC during lightning activity over Antarctic Peninsula

    Science.gov (United States)

    Suparta, W.; Nor, W. N. A. Wan Mohd

    2017-05-01

    This paper investigates the irregularities of vertical total electron content (VTEC) during lightning activity and geomagnetic quiet days over Antarctic Peninsula in year 2014. During the lightning event, the ionosphere may be disturbed which may cause disruption in the radio signal. Thus, it is important to understand the influence of lightning on VTEC in the study of upper-lower interaction. The lightning data is obtained from World Wide Lightning Location Network (WWLLN) and the VTEC data has analyzed from Global Positioning System (GPS) for O’Higgins (OHI3), Palmer (PALV), and Rothera (ROTH). The results demonstrate the VTEC variation of ∼0.2 TECU during low lightning activity which could be caused by energy dissipation through lightning discharges from troposphere into the thermosphere.

  20. Collisional Cascade Caclulations for Irregular Satellite Swarms in Fomalhaut b

    CERN Document Server

    Kenyon, Scott J

    2015-01-01

    We describe an extensive suite of numerical calculations for the collisional evolution of irregular satellite swarms around 1--300 M-earth planets orbiting at 120 AU in the Fomalhaut system. For 10--100 M-earth planets, swarms with initial masses of roughly 1% of the planet mass have cross-sectional areas comparable to the observed cross-sectional area of Fomalhaut b. Among 30--300 M-earth planets, our calculations yield optically thick swarms of satellites for ages of 1-10 Myr. Observations with HST and ground-based AO instruments can constrain the frequency of these systems around stars in the beta Pic moving group and possibly other nearby associations of young stars.

  1. Global scale ionospheric irregularities associated with thunderstorm activity

    CERN Document Server

    Pulinets, S A

    2002-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstor...

  2. Robust Fusion of Irregularly Sampled Data Using Adaptive Normalized Convolution

    Directory of Open Access Journals (Sweden)

    Schutte Klamer

    2006-01-01

    Full Text Available We present a novel algorithm for image fusion from irregularly sampled data. The method is based on the framework of normalized convolution (NC, in which the local signal is approximated through a projection onto a subspace. The use of polynomial basis functions in this paper makes NC equivalent to a local Taylor series expansion. Unlike the traditional framework, however, the window function of adaptive NC is adapted to local linear structures. This leads to more samples of the same modality being gathered for the analysis, which in turn improves signal-to-noise ratio and reduces diffusion across discontinuities. A robust signal certainty is also adapted to the sample intensities to minimize the influence of outliers. Excellent fusion capability of adaptive NC is demonstrated through an application of super-resolution image reconstruction.

  3. Combined radar observations of equatorial electrojet irregularities at Jicamarca

    Directory of Open Access Journals (Sweden)

    D. L. Hysell

    2007-03-01

    Full Text Available Daytime equatorial electrojet plasma irregularities were investigated using five distinct radar diagnostics at Jicamarca including range-time-intensity (RTI mapping, Faraday rotation, radar imaging, oblique scattering, and multiple-frequency scattering using the new AMISR prototype UHF radar. Data suggest the existence of plasma density striations separated by 3–5 km and propagating slowly downward. The striations may be caused by neutral atmospheric turbulence, and a possible scenario for their formation is discussed. The Doppler shifts of type 1 echoes observed at VHF and UHF frequencies are compared and interpreted in light of a model of Farley Buneman waves based on kinetic ions and fluid electrons with thermal effects included. Finally, the up-down and east-west asymmetries evident in the radar observations are described and quantified.

  4. Tracking breather dynamics in irregular sea state conditions

    CERN Document Server

    Chabchoub, A

    2016-01-01

    Breather solutions of the nonlinear Schr\\"odinger equation (NLSE) are known to be considered as backbone models for extreme events in the ocean as well as in Kerr media. These exact determinisitic rogue wave (RW) prototypes on a regular background describe a wide-range of modulation instability configurations. Alternatively, oceanic or electromagnetic wave fields can be of chaotic nature and it is known that RWs may develop in such conditions as well. We report an experimental study confirming that extreme localizations in an irregular oceanic JONSWAP wave field can be tracked back to originate from exact NLSE breather solutions, such as the Peregrine breather. Numerical NLSE as well as modified NLSE simulations are both in good agreement with laboratory experiments and highlight the significance of universal weakly nonlinear evolution equations in the emergence as well as prediction of extreme events in nonlinear dispersive media.

  5. Manufacturing of Cast Metal Foams with Irregular Cell Structure

    Directory of Open Access Journals (Sweden)

    Kroupová I.

    2015-06-01

    Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

  6. Constructing a logical, regular axis topology from an irregular topology

    Science.gov (United States)

    Faraj, Daniel A.

    2014-07-01

    Constructing a logical regular topology from an irregular topology including, for each axial dimension and recursively, for each compute node in a subcommunicator until returning to a first node: adding to a logical line of the axial dimension a neighbor specified in a nearest neighbor list; calling the added compute node; determining, by the called node, whether any neighbor in the node's nearest neighbor list is available to add to the logical line; if a neighbor in the called compute node's nearest neighbor list is available to add to the logical line, adding, by the called compute node to the logical line, any neighbor in the called compute node's nearest neighbor list for the axial dimension not already added to the logical line; and, if no neighbor in the called compute node's nearest neighbor list is available to add to the logical line, returning to the calling compute node.

  7. First Stellar Abundances in the Dwarf Irregular Galaxy IC 1613

    Science.gov (United States)

    Tautvaišienė, Gražina; Geisler, Doug; Wallerstein, George; Borissova, Jura; Bizyaev, Dmitry; Pagel, Bernard E. J.; Charbonnel, Corinne; Smith, Verne

    2007-12-01

    Chemical abundances in three M supergiants in the Local Group dwarf irregular galaxy IC 1613 have been determined using high-resolution spectra obtained with the UVES spectrograph on the ESO 8.2 m Kueyen telescope. A detailed synthetic-spectrum analysis has been used to determine the atmospheric parameters and abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Fe, Co, Ni, La, and Eu. We find the overall metallicity of the stars to be [Fe/H] = -0.67 ± 0.09 and the age 9-13 Myr, which is in excellent agreement with the present-day values in the age-metallicity relationship model of IC 1613 by Skillman et al. We have found that the three supergiants investigated have a mean [α/Fe] equal to about -0.1, which is lower than seen in Galactic stars at the same metallicity and is in agreement with the results obtained in other dwarf irregular galaxies. The oxygen abundances are in agreement with the upper values of the nebular oxygen determinations in IC 1613. The abundance ratios of s- and r-process elements to iron are enhanced relative to solar by about 0.3 dex. The abundance pattern of the elements studied is similar to that of the Small Magellanic Cloud, except for Co and Ni, which are underabundant in the SMC. The observed elemental abundances are generally in very good agreement with the recent chemical evolution model of Yuk and Lee. Based on observations collected with the Very Large Telescope and the 2.2 m Telescope of the European Southern Observatory within the Observing Programs 70.B-0361(A) and 072.D-0113(D).

  8. How Iapetus is Painted by Saturn's Irregular Satellites

    Science.gov (United States)

    Tamayo, Dan; Burns, J. A.; Hamilton, D. P.; Hedman, M. M.

    2010-10-01

    The leading hemisphere of Iapetus, Saturn's outermost regular satellite, is ten times darker than its trailing side. To explain this unique albedo distribution, Soter (1974) proposed that collisionally generated dust from the dark outer irregular satellite Phoebe has evolved inward due to radiation forces and coated Iapetus’ leading side. The recent discovery (Verbiscer et al. 2009) of the colossal Phoebe ring between the orbits of Iapetus and Phoebe indicates that Soter's mechanism is active at some level. . To calibrate the effectiveness of this source, we follow the histories of Phoebe-ring dust under the relevant perturbations and thereby evaluate the particles’ probability of striking Iapetus, as well as the expected spatial distribution on the Iapetan surface. We find that, of the long-lived particles (those larger than 4 µm), those larger than 10 µm are virtually certain to strike Iapetus. Their calculated distribution across the surface matches well the measured albedo pattern in longitude. To explain the observed bright polar caps, our computed polar-dust-deposition rates must be overwhelmed by sublimation products from equatorial regions as proposed in the thermal runaway model of Spencer & Denk (2010); we thus constrain the latter model. We also track the dust originating from all the other known irregular moons, finding that a substantial fraction of the material from retrograde moons would eventually coat Iapetus--perhaps explaining why the spectrum of Iapetus’ dark material differs somewhat from Phoebe's (Buratti et al. 2005). We find that dust from lower-eccentricity moons with inclinations nearer 180° is more likely to strike Iapetus. . Finally, of those dust particles that do not strike Iapetus, we find that most land on Titan, with a smaller fraction hitting Hyperion. As has been previously conjectured (Burns et al. 1996), such exogenous dust, coupled with Hyperion's chaotic rotation could explain Hyperion's roughly uniform, moderate

  9. How to analyse irregularly sampled geophysical time series?

    Science.gov (United States)

    Eroglu, Deniz; Ozken, Ibrahim; Stemler, Thomas; Marwan, Norbert; Wyrwoll, Karl-Heinz; Kurths, Juergen

    2015-04-01

    One of the challenges of time series analysis is to detect dynamical changes in the dynamics of the underlying system.There are numerous methods that can be used to detect such regime changes in regular sampled times series. Here we present a new approach, that can be applied, when the time series is irregular sampled. Such data sets occur frequently in real world applications as in paleo climate proxy records. The basic idea follows Victor and Purpura [1] and considers segments of the time series. For each segment we compute the cost of transforming the segment into the following one. If the time series is from one dynamical regime the cost of transformation should be similar for each segment of the data. Dramatic changes in the cost time series indicate a change in the underlying dynamics. Any kind of analysis can be applicable to the cost time series since it is a regularly sampled time series. While recurrence plots are not the best choice for irregular sampled data with some measurement noise component, we show that a recurrence plot analysis based on the cost time series can successfully identify the changes in the dynamics of the system. We tested this method using synthetically created time series and will use these results to highlight the performance of our method. Furthermore we present our analysis of a suite of calcite and aragonite stalagmites located in the eastern Kimberley region of tropical Western Australia. This oxygen isotopic data is a proxy for the monsoon activity over the last 8,000 years. In this time series our method picks up several so far undetected changes from wet to dry in the monsoon system and therefore enables us to get a better understanding of the monsoon dynamics in the North-East of Australia over the last couple of thousand years. [1] J. D. Victor and K. P. Purpura, Network: Computation in Neural Systems 8, 127 (1997)

  10. ESA' s novel gravitational modeling of irregular planetary bodies

    Science.gov (United States)

    Ortega, Guillermo

    A detailed understanding and modeling of the gravitational modeling is required for realistic investigation of the dynamics of orbits close to irregularly shaped bodies. Gravity field modelling up to a certain maximum spherical harmonic degree N involves N2 unkown spherical harmonic coefficients or complex harmonics. The corresponding number of matrix entries reaches till N4 . For missions like CHAMP, GRACE or GOCE, the maximum degree of resolution is 75, 150 and 300 respectively. Therefore, the number of unknowns for a satellite like GOCE will be around 100.000. Since these missions usually fly for a period of time of several years, the number of observations is huge. Hence, gravity field recovery from these missions is a high demanding task. The classical approaches like spherical expansion of the potential lead generally to a high number of coefficients, which reduce the software computational efficiency of the orbit propagation and which have mostly a limited physical meaning. One of the main targets of the activity is the modelling of asteroids, small moons, and cometary bodies. All celestial bodies are irregular by definition. However, the scope of the activity is broad enough as to be able to use the models and the software in quasy-regular bodies as well. Therefore the models and tools could be used for bodies such as the Moon, Mars, Venus, Deimos, Europa, Eros, Mathilda, and Churyumov-Gerasimenko, etc., being these applications relevant for scientific (Rosetta, Bepi Colombo), exploration (Exo-Mars), NEO mitigation (Don Quijote) and Earth observation (GOCE) missions of ESA.

  11. Efficient Clustering for Irregular Geometries Based on Identification of Concavities

    Directory of Open Access Journals (Sweden)

    Velázquez-Villegas Fernando

    2014-04-01

    Full Text Available Two dimensional clustering problem has much relevance in applications related to the efficient use of raw material, such as cutting stock, packing, etc. This is a very complex problem in which multiple bodies are accommodated efficiently in a way that they occupy as little space as possible. The complexity of the problem increases with the complexity of the bodies. Clearly the number of possible arrangements between bodies is huge. No Fit Polygon (NFP allows to determine the entire relative positions between two patterns (regular or irregular in contact, non-overlapping, therefore the best position can be selected. However, NFP generation requires a lot of calculations; besides, selecting the best cluster isn’t a simple task because, between two irregular patterns in contact, hollows (unusable areas and external concavities (usable areas can be produced. This work presents a quick and simple method to reduce calculations associated with NFP generation and to minimize unusable areas in a cluster. This method consists of generating partial NFP, just on concave regions of the patterns, and selecting the best cluster using a total weighted efficiency, i.e. a weighted value of enclosure efficiency (ratio of occupied area on convex hull area and hollow efficiency (ratio of occupied area on cluster area. The proposed method produces similar results as those obtained by other methods; however the shape of the clusters obtained allows to accommodate more parts in similar spaces, which is a desirable result when it comes to optimizing the use of material. We present two examples to show the performance of the proposal.

  12. Time-frequency processing of track irregularities in high-speed train

    Science.gov (United States)

    Ning, Jing; Lin, Jianhui; Zhang, Bing

    2016-01-01

    Track irregularities are the main source of vehicle vibration. With the increase in the speed, the track irregularities have become a more significant issue of concerned. The axle box acceleration signals can be obtained for analyzing the track irregularities, but the signals are usually non-stationary and signal processing results are not normally satisfied with the ordinary way. Thus, time-frequency distribution analysis is proposed to use in this study. To minimize the cross-terms, a new method based on Empirical Mode Decomposition (EMD) and Cohen's class distribution has been developed and advanced. This approach has been tested with three typical simulation signals and then applied to analyze the track irregularities. The result is consistent with the result from track inspection cars. This indicates this new algorithm is suitable for analyzing the track irregularities. It can be applied in rail irregularity measurement to compensate some shortages of the track inspection cars.

  13. Human Rights of Irregular Immigrants: A Challenge for the Universality of Human Rights

    OpenAIRE

    Luljeta Ikonomi

    2013-01-01

    Irregular immigration is a phenomenon with a substantial impact for the majority of the countries. The paper analyses whether there is an adequate human rights framework for protection of irregular immigrants or whether the irregular status exempts the migrants from the protection of international human rights law. If this is the case, then the human rights universality has failed. The paper takes into consideration the developments in the International and EU Law, as well as in the jurisprud...

  14. Application of generalized separation of variables to solving mixed problems with irregular boundary conditions

    Science.gov (United States)

    Gasymov, E. A.; Guseinova, A. O.; Gasanova, U. N.

    2016-07-01

    One of the methods for solving mixed problems is the classical separation of variables (the Fourier method). If the boundary conditions of the mixed problem are irregular, this method, generally speaking, is not applicable. In the present paper, a generalized separation of variables and a way of application of this method to solving some mixed problems with irregular boundary conditions are proposed. Analytical representation of the solution to this irregular mixed problem is obtained.

  15. Simple approximation method for determining field factors and tissue-peap ratios of irregularly shaped fields

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Fujio; Kumagai, Kozo; Iseri, Takumi; Kawano, Tsutomu (National Hospital of Kumamoto (Japan))

    1991-04-01

    Dose calculation of irregularly shaped fields can be made by the Clarkson technique, which however requires considerable time and is thus not practical. We investigated a simple approximation method for determining field factors (F{sub A}) and tissue-peak ratios (TPRs) for irregularly shaped fields. By this method, we approximated scatter dose by the ratio of area for an irregularly shaped field to that for the overall field (without blocking). Maximum error of equivalent square fields as determined by this method for irregularly shaped fields was -1.3% for field factors, +2.1% for TPRs and +1.4% for the F{sub A} x TPRs. (author).

  16. Irregular and regular LDPC codes with high spectrum efficiency modulation in image transmission over fading channel

    Institute of Scientific and Technical Information of China (English)

    Ma Piming; Yuan Dongfeng

    2005-01-01

    If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC codes with 16QAM/64QAM modulation to improve both efficiency and reliability. Simulaton results show that LDPC codes are good coding schemes over fading channel in image communication with lower system complexity. More over, irregular codes can obtain a code gain of about 0.7 dB compared with regular ones when BER is 10-4. So the irregular LDPC codes are more suitable for image transmission than the regular codes.

  17. Characterization of irregular seeds on gibbsites precipitated from caustic aluminate solutions

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-hui; CHEN Qi-yuan; YIN Zhou-lan; YIN Zhi-min

    2006-01-01

    The irregular surface of seeds on which gibbsites are precipitated from caustic aluminate solutions, was investigated according to the fractal theory. Two kinds of fractal dimensions were used to characterize these irregularity. Box-dimension and spectral dimension are based on the SEM images of seeds and diffusive dynamic equation ofthe precipitation respectively. Both these two dimensions are affected by the reaction temperature, evolved with different reaction conditions and can reflect the influence of irregularity of seeds on the precipitation rate. Box dimension is fit for the characterization of the irregular morphology of seeds, while spectral dimension can explain the fractal dynamic behavior.

  18. Irregularities in Pump-Induced Tilt Above Shallow Aquifers

    Science.gov (United States)

    Kuempel, H. J.; Fabian, M.

    2003-12-01

    Near surface ground tilt induced by the extraction of fluids from subsurface reservoirs has repeatedly been used to constrain reservoir parameters. In general, pump-induced tilt is found to be proportional in strength to the pore pressure gradient created by the pumping, to be a function of poroelastic rock parameters, and to depend on the geometric configuration of the tilt sensor and the productive sections of a well. Assuming radial flow, the strike of the tilt signal should point toward the productive well. However, inversion of near surface tilt can be hampered through irregularities in the pump-induced signal and suffer from insufficient knowledge of the influence of heterogeneities in the subsoil, either within or above the reservoir. We can learn more about the impact of such heterogeneities and reduce ambiguities by analyzing case studies. New observational data from 3 test sites in Germany confirm that a variety of causes can produce irregularities in pump-induced surface deformation, namely: (1) The strike of a tilt signal can considerably deviate from the direction toward the active well. A reason could be that the steepest effective pore pressure gradient builds up in another than radial direction (thereby generating anisotropic fluid flow). Accordingly, tilt hodographs for a complete pump cycle may be elliptic rather than follow a line. (2) The normal rule of how the signal strength depends on the horizontal and the vertical distance may be violated. Structural heterogeneities in the subsurface are the most likely cause for this behaviour. (3) Recovery of the induced tilt signal following the cessation of pumping can be incomplete. This could indicate a non-reversible compaction possibly due to overexploitation of a reservoir. (4) A transient sign reversal of ground tilt may occur during the build-up phase of the signal. This feature could be an analogue to the so-called Noordbergum effect occasionally seen in the response of well levels at locations

  19. Reconstructing regional climate networks from irregularly sampled satellite data

    Science.gov (United States)

    Wiedermann, Marc; Donner, Reik V.; Sykioti, Olga; Papadimitriou, Constantinos; Kurths, Jürgen

    2015-04-01

    With the increasing availability of remote sensing data Earth System Analysis has taken a great step forward. Satellite data with high resolution in time and space allow for an in-depth analysis of small-scale processes in the climate as well as ecosystems. This data type, however, also harbors crucial conceptual complications. First, depending on whether the satellite is orbiting on an ascending or descending path systematic biases are induced into the dataset and both measurements can not be evaluated simultaneously without an appropriate preprocessing. Second, remote sensing data are usually not produced with equidistant temporal sampling, but might contain huge gaps, due to cloud cover or maintenance work and irregular time steps, due to the orbiting time of the satellite. In this work, we utilize sea surface temperature (SST) data obtained from the SMOS satellite as part of ESA's Earth Explorer Mission to study small-scale regional interactions between different parts of the Mediterranean, Aegean and Black Sea. In a first step, we create homogeneous time series for each grid point by combining data from ascending and descending satellite paths by utilizing principal component and singular spectrum analysis. To address the issue of irregular temporal sampling we utilize a kernel weighted version of the linear cross-correlation function to compute lagged correlations between all pairs of grid points in the dataset. By setting a threshold to the thus obtained correlation matrix we obtain a binary matrix which can be interpreted as the adjacency matrix of a complex network. We then use tools from complex network theory to study regional interdependencies in the study area for different time lags of up to forty days. We find that the obtained networks represent well the observed average wind directions and speeds and display interaction structures between small regions in the Aegean Sea, which are in good agreement with earlier observations. The methods presented

  20. Regional climate network analysis from irregularly sampled satellite data

    Science.gov (United States)

    Wiedermann, Marc; Sykioti, Olga; Papadimitriou, Constantinos; Balasis, George; Kurths, Jürgen; Donner, Reik V.

    2016-04-01

    With the increasing availability of remote sensing data Earth System Analysis has taken a great step forward. This type of data, however, also harbors a variety of conceptual complications. First, depending on whether the satellite is orbiting on an ascending or descending path systematic biases are induced into the data, and both measurements cannot be evaluated simultaneously without an appropriate preprocessing. Second, remote sensing data are usually not produced with equidistant temporal sampling, but might contain huge gaps and irregular time steps. Third, the time period covered by the data is often too short to perform an appropriate seasonal detrending. Here, we propose a general framework to create homogeneous anomalized time series for a (multivariate) satellite data set by combining time series from ascending and descending satellite paths or even different missions using principal component and singular spectrum analysis. We then exemplarily apply our method to sea surface temperature data obtained from the SMOS satellite mission to study small-scale regional correlative patterns covering different parts of the Aegean Sea. To address the issue of irregular temporal sampling we utilize a kernel weighted version of the linear cross-correlation function to compute lagged correlations between all pairs of grid points in the data set. By binarizing the thus obtained matrices, we obtain a network representation of the system's similarity structure. Ultimately, we use tools from complex network theory to study regional interdependencies in the study area for different time lags of up to forty days. We find that the obtained networks represent well the observed average wind directions and speeds and display interaction structures between small regions in the Aegean Sea, which are in good agreement with earlier observations. In a second step, we extend the study area to the whole Mediterranean and Black Sea and investigate lagged interactions between these two

  1. Representation of the Gravity Field of Irregularly Shaped Bodies

    Science.gov (United States)

    Reimond, Stefan; Baur, Oliver

    2015-04-01

    Exploratory space missions to small bodies in our solar system have gained importance over the last few decades. The well-renowned mission Rosetta set a milestone in space science history when it successfully lowered its mini-lab Philae onto the surface of Comet 67P/Churyumov-Gerasimenko in November 2014. Knowledge of the gravitational field of a small body, e.g. a comet or asteroid, is crucial in order to study a spacecraft's motion in its environment and to infer geophysical properties. Traditionally, the gravitational field of a body is modeled by means of spherical harmonics. For bodies of near-spherical shape (such as the Earth), this is an adequate method, because the reference figure, i.e. a sphere, snugly fits the body. For irregularly shaped bodies, however, the adoption of spherical harmonics might be a sub-optimal choice. As an alternative, oblate or prolate spheroidal harmonics (OH or PH, reference figure is an ellipsoid of revolution) or ellipsoidal harmonics (EH, reference figure is a tri-axial ellipsoid) should be considered. The latter will in general be the best choice in terms of aptness of the reference figure. The downside of EH, however, lies in the considerably increased (numerical) complexity of the computation of the base functions, i.e., the Lamé functions of the first and second kind. OH or PH represent a promising path down the middle. Elongated bodies (such as Asteroid 433 Eros) are often similarly well approximated by a prolate spheroid as by the corresponding tri-axial ellipsoid. Contracted bodies, on the other hand, can be described accordingly well by means of an oblate spheroid. We compare the SH, OH, PH and EH gravitational field parameterizations for different celestial bodies, including Rosetta's target comet 67P. The tasks are as follows: Based on the polyhedral representation of a body's shape model, the gravitational potential and acceleration vector is computed for evenly or irregularly distributed points inside or outside

  2. Response reduction factor of irregular RC buildings in Kathmandu valley

    Science.gov (United States)

    Chaulagain, Hemchandra; Rodrigues, Hugo; Spacone, Enrico; Guragain, Ramesh; Mallik, Radhakrishna; Varum, Humberto

    2014-09-01

    Most current seismic design includes the nonlinear response of a structure through a response reduction factor ( R). This allows the designer to use a linear elastic force-based approach while accounting for nonlinear behavior and deformation limits. In fact, the response reduction factor is used in modern seismic codes to scale down the elastic response of a structure. This study focuses on estimating the actual ` R' value for engineered design/construction of reinforced concrete (RC) buildings in Kathmandu valley. The ductility and overstrength of representative RC buildings in Kathmandu are investigated. Nonlinear pushover analysis was performed on structural models in order to evaluate the seismic performance of buildings. Twelve representative engineered irregular buildings with a variety of characteristics located in the Kathmandu valley were selected and studied. Furthermore, the effects of overstrength on the ductility factor, beam column capacity ratio on the building ductility, and load path on the response reduction factor, are examined. Finally, the results are further analyzed and compared with different structural parameters of the buildings.

  3. Non-linear analysis of vibrations of irregular plates

    Science.gov (United States)

    Lobitz, D. W.; Nayfeh, A. H.; Mook, D. T.

    1977-01-01

    A numerical perturbation method is used to investigate the forced vibrations of irregular plates. Nonlinear terms associated with the midplane stretching are retained in the analysis. The numerical part of the method involves the use of linear, finite element techniques to determine the free oscillation mode shapes and frequencies and to obtain the linear midplane stress resultants caused by the midplane stretching. Representing the solution as an expansion in terms of these linear mode shapes, these modes and the resultants are used to determine the equations governing the time-dependent coefficients of this expansion. These equations are solved by using the method of multiple scales. Specific solutions are given for the main-resonant vibrations of an elliptical plate in the presence of internal resonances. The results indicate that modes other than the driven mode can be drawn into the steady state response. Though the excitation is composed of a single harmonic, the response may not be periodic. Moreover, the particular types of responses that can occur are highly dependent on the mode being excited and are sensitive to small geometrical changes.

  4. New OpenMP Directives for Irregular Data Access Loops

    Directory of Open Access Journals (Sweden)

    J. Labarta

    2001-01-01

    Full Text Available Many scientific applications involve array operations that are sparse in nature, ie array elements depend on the values of relatively few elements of the same or another array. When parallelised in the shared-memory model, there are often inter-thread dependencies which require that the individual array updates are protected in some way. Possible strategies include protecting all the updates, or having each thread compute local temporary results which are then combined globally across threads. However, for the extremely common situation of sparse array access, neither of these approaches is particularly efficient. The key point is that data access patterns usually remain constant for a long time, so it is possible to use an inspector/executor approach. When the sparse operation is first encountered, the access pattern is inspected to identify those updates which have potential inter-thread dependencies. Whenever the code is actually executed, only these selected updates are protected. We propose a new OpenMP clause, indirect, for parallel loops that have irregular data access patterns. This is trivial to implement in a conforming way by protecting every array update, but also allows for an inspector/executor compiler implementation which will be more efficient in sparse cases. We describe efficient compiler implementation strategies for the new directive. We also present timings from the kernels of a Discrete Element Modelling application and a Finite Element code where the inspector/executor approach is used. The results demonstrate that the method can be extremely efficient in practice.

  5. Mechanically Milled Irregular Zinc Nanoparticles for Printable Bioresorbable Electronics.

    Science.gov (United States)

    Mahajan, Bikram K; Yu, Xiaowei; Shou, Wan; Pan, Heng; Huang, Xian

    2017-02-20

    Bioresorbable electronics is predominantly realized by complex and time-consuming anhydrous fabrication processes. New technology explores printable methods using inks containing micro- or nano-bioresorbable particles (e.g., Zn and Mg). However, these particles have seldom been obtained in the context of bioresorbable electronics using cheap, reliable, and effective approaches with limited study on properties essential to printable electronics. Here, irregular nanocrystalline Zn with controllable sizes and optimized electrical performance is obtained through ball milling approach using polyvinylpyrrolidone (PVP) as a process control agent to stabilize Zn particles and prevent cold welding. Time and PVP dependence of the ball milled particles are studied with systematic characterizations of morphology and composition of the nanoparticles. The results reveal crystallized Zn nanoparticles with a size of ≈34.834 ± 1.76 nm and low surface oxidation. The resulting Zn nanoparticles can be readily printed onto bioresorbable substrates and sintered at room temperature using a photonic sintering approach, leading to a high conductivity of 44 643 S m(-1) for printable zinc nanoparticles. The techniques to obtain Zn nanoparticles through ball milling and processing them through photonic sintering may potentially lead to a mass fabrication method for bioresorbable electronics and promote its applications in healthcare, environmental protection, and consumer electronics.

  6. ON THE STAR FORMATION LAW FOR SPIRAL AND IRREGULAR GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G., E-mail: bge@us.ibm.com [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

    2015-12-01

    A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical timescale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical timescale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ∼100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.

  7. On the Star Formation Law for Spiral and Irregular Galaxies

    CERN Document Server

    Elmegreen, Bruce G

    2015-01-01

    A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical time scale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical time scale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and su...

  8. The periodic dynamics of the irregular heterogeneous celestial bodies

    Science.gov (United States)

    Lan, Lei; Yang, Mo; Baoyin, Hexi; Li, Junfeng

    2017-02-01

    In this paper, we develop a methodology to study the periodic dynamics of irregular heterogeneous celestial bodies. Heterogeneous bodies are not scarce in space. It has been found that bodies, such as 4 Vesta, 624 Hektor, 87 Sylvia, 16 Psyche and 25143 Itokawa, may all have varied internal structures. They can be divided into large-scale and small-scale cases. The varied internal structures of large-scale bodies always result from gradient pressure inside, which leads to compactness differences of the inner material. However, the heterogeneity of a small-scale body is always reflected by the different densities of different areas, which may originate from collision formation from multiple objects. We propose a modeling procedure for the heterogeneous bodies derived from the conventional polyhedral method and then compare its dynamical characteristics with those of the homogeneous case. It is found that zero-velocity curves, positions of equilibrium points, types of bifurcations in the continuation of the orbital family and the stabilities of periodic orbits near the heterogeneous body are different from those in the homogeneous case. The suborbicular orbits near the equatorial plane are potential parking orbits for a future mission, so we discuss the switching of the orbital stability of the family because it has fundamental significance to orbit maintenance and operations around actual asteroids.

  9. Irregular topography at the Earth’s inner core boundary

    Science.gov (United States)

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-01-01

    Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

  10. Climatic irregular staircases: generalized acceleration of global warming.

    Science.gov (United States)

    De Saedeleer, Bernard

    2016-01-27

    Global warming rates mentioned in the literature are often restricted to a couple of arbitrary periods of time, or of isolated values of the starting year, lacking a global view. In this study, we perform on the contrary an exhaustive parametric analysis of the NASA GISS LOTI data, and also of the HadCRUT4 data. The starting year systematically varies between 1880 and 2002, and the averaging period from 5 to 30 yr - not only decades; the ending year also varies . In this way, we uncover a whole unexplored space of values for the global warming rate, and access the full picture. Additionally, stairstep averaging and linear least squares fitting to determine climatic trends have been sofar exclusive. We propose here an original hybrid method which combines both approaches in order to derive a new type of climatic trend. We find that there is an overall acceleration of the global warming whatever the value of the averaging period, and that 99.9% of the 3029 Earth's climatic irregular staircases are rising. Graphical evidence is also given that choosing an El Niño year as starting year gives lower global warming rates - except if there is a volcanic cooling in parallel. Our rates agree and generalize several results mentioned in the literature.

  11. Research of CRP-based irregular 2D seismic acquisition

    Institute of Scientific and Technical Information of China (English)

    Zhao Hu; Yin Cheng; He Guang-Ming; Chen Ai-Ping; Jing Long-Jiang

    2015-01-01

    Seismic exploration in the mountainous areas of western Chinese is extremely diffi cult because of the complexity of the surface and subsurface, which results in shooting difficulties, seismic data with low signal-to-noise ratio, and strong interference. The complexity of the subsurface structure leads to strong scattering of the refl ection points; thus, the curved-line acquisition method has been used. However, the actual subsurface structural characteristics have been rarely considered. We propose a design method for irregular acquisition based on common refl ection points (CRP) to avoid diffi cult-to-shoot areas, while considering the structural characteristics and CRP positions and optimizing the surface-receiving line position. We arrange the positions of the receiving points to ensure as little dispersion of subsurface CRP as possible to improve the signal-to-noise ratio of the seismic data. We verify the applicability of the method using actual data from a site in Sichuan Basin. The proposed method apparently solves the problem of seismic data acquisition and facilitates seismic exploration in structurally complex areas.

  12. Climatic irregular staircases: generalized acceleration of global warming

    Science.gov (United States)

    de Saedeleer, Bernard

    2016-01-01

    Global warming rates mentioned in the literature are often restricted to a couple of arbitrary periods of time, or of isolated values of the starting year, lacking a global view. In this study, we perform on the contrary an exhaustive parametric analysis of the NASA GISS LOTI data, and also of the HadCRUT4 data. The starting year systematically varies between 1880 and 2002, and the averaging period from 5 to 30 yr — not only decades; the ending year also varies . In this way, we uncover a whole unexplored space of values for the global warming rate, and access the full picture. Additionally, stairstep averaging and linear least squares fitting to determine climatic trends have been sofar exclusive. We propose here an original hybrid method which combines both approaches in order to derive a new type of climatic trend. We find that there is an overall acceleration of the global warming whatever the value of the averaging period, and that 99.9% of the 3029 Earth’s climatic irregular staircases are rising. Graphical evidence is also given that choosing an El Niño year as starting year gives lower global warming rates — except if there is a volcanic cooling in parallel. Our rates agree and generalize several results mentioned in the literature.

  13. FIGGS2: An HI survey of extremely faint irregular galaxies

    CERN Document Server

    Patra, Narendra Nath; Karachentsev, Igor D; Sharina, Margarita E

    2016-01-01

    We present the observations and first results from the FIGGS2 survey. FIGGS2 is an extension of the earlier Faint Irregular Galaxies GMRT survey (FIGGS) towards faint luminosity end. The sample consists of 20 galaxies of which 15 were detected in HI 21cm line using the Giant Meter-wave Radio Telescope (GMRT). The median blue band magnitude of our sample is ~ -11.6, which is more than one magnitude fainter than earlier FIGGS survey. From our GMRT observations we find that, for many of our sample galaxies, the HI disks are offset from their optical disks. The HI diameters of the FIGGS2 galaxies show a tight correlation with their HI mass. The slope of the correlation is 2.08 +/- 0.20 similar to what is found for FIGGS galaxies. We also find that for almost all galaxies, the HI disks are larger than the optical disks which is a common trend for dwarf or spiral galaxies. The mean value of the ratio of HI to optical diameter is ~ 1.54.

  14. Irregular persistent activity induced by synaptic excitatory feedback

    Directory of Open Access Journals (Sweden)

    Francesca Barbieri

    2007-11-01

    Full Text Available Neurophysiological experiments on monkeys have reported highly irregular persistent activity during the performance of an oculomotor delayed-response task. These experiments show that during the delay period the coefficient of variation (CV of interspike intervals (ISI of prefrontal neurons is above 1, on average, and larger than during the fixation period. In the present paper, we show that this feature can be reproduced in a network in which persistent activity is induced by excitatory feedback, provided that (i the post-spike reset is close enough to threshold , (ii synaptic efficacies are a non-linear function of the pre-synaptic firing rate. Non-linearity between presynaptic rate and effective synaptic strength is implemented by a standard short-term depression mechanism (STD. First, we consider the simplest possible network with excitatory feedback: a fully connected homogeneous network of excitatory leaky integrate-and-fire neurons, using both numerical simulations and analytical techniques. The results are then confirmed in a network with selective excitatory neurons and inhibition. In both the cases there is a large range of values of the synaptic efficacies for which the statistics of firing of single cells is similar to experimental data.

  15. Measuring border irregularities of skin lesions using fractal dimensions

    Science.gov (United States)

    Ng, Vincent T. Y.; Lee, Tim K.

    1996-09-01

    Malignant melanoma is the most common cancer in people less than 35 years of age and incident rates are increasing by approximately 5 percent per annum in many white populations, including British Columbia, Canada. In 1994, a clinical study has been established to digitize melanocytic lesions under a controlled environment. Lesions are digitized from patients who are referred to the Colored Pigment Lesion Clinic in the University of British Columbia. In this paper, we investigate how to use fractal dimensions (FDs) in measuring the irregularity of a skin lesion. In a previous project, we have experimented with 6 different methods to calculate fractal dimensions on a small number of images of skin lesions, and the simple box-counting method performed the best. However, the method did not exploit the intensity information of the images. With the new set of images which are digitized under the controlled environment, we utilize the differential box counting method to exploit such information. Four FD measures, including the direct FD, the horizontal and the vertical smoothing FDs, and the multi- fractal dimension of order two, are calculated based on the original color images. In addition, these 4 FD features are repeatedly calculate for the blue band of the images. This paper reports the different features through the calculations of the fractal dimensions and compares their differentiation power in the use of diagnosis of images of skin lesions.

  16. Irregular topography at the Earth's inner core boundary.

    Science.gov (United States)

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-05-15

    Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable.

  17. Influence of Ionospheric Irregularities on GNSS Remote Sensing

    Directory of Open Access Journals (Sweden)

    M. V. Tinin

    2015-01-01

    Full Text Available We have used numerical simulation to study the effects of ionospheric irregularities on accuracy of global navigation satellite system (GNSS measurements, using ionosphere-free (in atmospheric research and geometry-free (in ionospheric research dual-frequency phase combinations. It is known that elimination of these effects from multifrequency GNSS measurements is handi-capped by diffraction effects during signal propagation through turbulent ionospheric plasma with the inner scale being smaller than the Fresnel radius. We demonstrated the possibility of reducing the residual ionospheric error in dual-frequency GNSS remote sensing in ionosphere-free combination by Fresnel inversion. The inversion parameter, the distance to the virtual screen, may be selected from the minimum of amplitude fluctuations. This suggests the possibility of improving the accuracy of GNSS remote sensing in meteorology. In the study of ionospheric disturbances with the aid of geometry-free combination, the Fresnel inversion eliminates only the third-order error. To eliminate the random TEC component which, like the measured average TEC, is the first-order correction, we should use temporal filtering (averaging.

  18. Thick film traps with an irregular film. Preparation and evaluation.

    Science.gov (United States)

    Kloskowski, Adam; Pettersson, Johan; Roeraade, Johan

    2004-05-07

    A new method for preparation of sorbent-based ultra-thick film traps for concentration of trace volatile components from gaseous matrices is described. The procedure is based on blowing a prepolymer (polydimethylsiloxane) through a capillary tube, forming an irregular film of stationary phase. Subsequently, the prepolymer is immobilized in a few seconds by heating to 200 degrees C. Evaluation of the performance of the new traps showed that the loss of efficiency, compared to regular smooth film traps is only on the order of 20-30%. In terms of breakthrough volume, this loss in performance is rather insignificant. The technology is extremely simple and allows a rapid and cheap production of a large number of ultra-thick film traps, even in non-specialized laboratories. The method can be applied to any type of cross-linkable stationary phase, thereby expanding the scope of sorbent-based trapping and preconcentration concept. Many applications are anticipated in trace and ultra-trace analysis in a wide range of fields, such as environmental chemistry, polymers, food and process analysis.

  19. Bubble-Induced Star Formation in Dwarf Irregular Galaxies

    CERN Document Server

    Kawata, Daisuke; Barnes, David J; Grand, Robert J J; Rahimi, Awat

    2013-01-01

    To study the star formation and feedback mechanism, we simulate the evolution of an isolated dwarf irregular galaxy (dIrr) in a fixed dark matter halo, similar in size to WLM. We use the new version of our original N-body/smoothed particle chemodynamics code, GCD+, which adopts improved hydrodynamics, metal diffusion between the gas particles and new modelling of star formation and stellar wind and supernovae (SNe) feedback. Comparing the simulations with and without stellar feedback effects, we demonstrate that the collisions of bubbles produced by strong feedback can induce star formation in a more widely spread area. We also demonstrate that the metallicity in star forming regions is kept low due to the mixing of the metal-rich bubbles and the metal-poor inter-stellar medium. Our simulations also suggest that the bubble-induced star formation leads to many counter-rotating stars. The bubble-induced star formation could be a dominant mechanism to maintain star formation in dIrrs, which is different from lar...

  20. Three-dimensional CLEM-LES of irregular detonation propagation

    Science.gov (United States)

    Maxwell, Brian; Radulescu, Matei

    2016-11-01

    Recently, thin-channel experiments and 2D simulations have been conducted in order to investigate the effect of turbulent mixing rates on the structure of irregular detonation wave propagation. Furthermore, the dependence of the observed cell pattern, and also the reaction zone thickness, on the mixing of burned products with pockets of unburned gases, was investigated. The current work now includes 3D simulations, which are conducted to provide further validation of, and insight into, the 2D results. All simulations have been conducted using the Compressible Linear Eddy Model for Large Eddy Simulation (CLEM-LES). To date, the 3D results are found to match closely the previous 2D results. The agrreement is partly due to sufficient resolution of the large scale fluid motions, which are observed experimentally to be predominant in only two directions. Furthermore, the CLEM-LES methodology incorporates 3D mixing effects at the subgrid level. Finally, it was found that turbulent fluctuations on the subgrid were found to give rise to statistically lower than average propagation velocities on the wave front. This lead to longer ignition delays for large amounts of gas passing through the wave, giving rise to the unburned pockets of gas observed experimentally. Authors would like to acknowledge NSERC and Shell for project funding.

  1. Observational study of daytime ionospheric irregularities associated with typhoon

    Institute of Scientific and Technical Information of China (English)

    XIAO SaiGuan; SHI JianKui; ZHANG DongHe; HAO YongQiang; HUANG WeiQuan

    2012-01-01

    Spread-F is a manifestation of ionospheric irregularities and generally takes place at nighttime.However,it can also be observed seldom at daytime.It is recognized that acoustic gravity waves (AGWs) play an important role in triggering plasma instability which results in spread-F in the ionosphere.The typhoon is a main source of the AGWs.In this paper,two cases of ionospheric daytime spread-F in the period of typhoon were analyzed.One case was on July 29,1988 and the other was on August 01,1989.The results showed the following:1) There were some wave-like disturbances appearing in the HF Doppler records firstly,consequently the Doppler echo traces became scattered,which indicated that the ionospheric spread-F was triggered; 2) the blurred echo traces in the both two cases appeared in the morning (08:30-11:30 Beijing time) and lasted for more than two hours; 3) with the blurred echoes gradually weakening,the traveling ionospheric disturbances (TIDs) still existed and became clearer; 4) the frequency shifts in the two cases were both positive,implying the effective reflecting surface of the radio wave in the ionosphere moved downwards.These results provide good observational evidence for daytime spread-F during the typhoon period in Asian region.

  2. Traditional and Model Based Assay of Irregular Geometry Items

    Energy Technology Data Exchange (ETDEWEB)

    MOORE, FRANK S.; SALAYMEH, SALEEM

    2005-06-15

    The Analytical Development Section (ADS) of SRNL was requested to perform a waste disposal assay of two heater boxes which had been used in the HB Line dissolvers. They had been sent to SRNL for study to make recommendations on how to prevent future failure of the units when they were replaced. The study having been completed, the units needed to be characterized prior to sending to Solid Waste for disposal. An assay station consisting of a turntable, HPGe detector, CANBERRA Inspector, transmission source and a portable computer was set up to do the required assays. The assays indicate the presence of U-235, Pu-239 and Cs-137. No measurable amounts of U-235 or Pu-239 were found. Therefore the Minimum Detectable Activities for U-235 and Pu-239 were calculated. For Heater Box 1, 0.23 grams of U-235 and 0.24 grams of Pu-239. For Heater Box 2, the results were 0.21 grams of U-235 and 0.21 grams of Pu-239. This paper describes and documents the assays employed to determine the amount of U, Pu and Cs contents of the heater boxes. The paper provides results of SNM assays using traditional calibration of the system and on one based on modeling. It also provides the scientific community with data that will assist the user in determining the method of choice for assaying items with irregular geometries.

  3. A Star Formation Law for Dwarf Irregular Galaxies

    CERN Document Server

    Elmegreen, Bruce G

    2015-01-01

    The radial profiles of gas, stars, and far ultraviolet radiation in 20 dwarf Irregular galaxies are converted to stability parameters and scale heights for a test of the importance of two-dimensional (2D) instabilities in promoting star formation. A detailed model of this instability involving gaseous and stellar fluids with self-consistent thicknesses and energy dissipation on a perturbation crossing time give the unstable growth rates. We find that all locations are effectively stable to 2D perturbations, mostly because the disks are thick. We then consider the average volume densities in the midplanes, evaluated from the observed HI surface densities and calculated scale heights. The radial profiles of the star formation rates are equal to about 1% of the HI surface densities divided by the free fall times at the average midplane densities. This 1% resembles the efficiency per unit free fall time commonly found in other cases. There is a further variation of this efficiency with radius in all of our galaxi...

  4. THE INCLINATION OF THE DWARF IRREGULAR GALAXY HOLMBERG II

    Directory of Open Access Journals (Sweden)

    F. J. Sánchez-Salcedo

    2014-01-01

    Full Text Available Damos restricciones al ́angulo de inclinaci ́on del disco de H i de la galaxia irregular enana Holmberg II (Ho II a partir de un an ́alisis de la estabilidad gravita cional del disco de gas en las partes externas. Encontramos que se requiere un ́angulo de inclinaci ́on medio de 27 ◦ y, por lo tanto, una velocidad circular en su parte plana de ≈ 60 km s − 1 , para tener un grado de estabilidad similar al que tienen otras galaxias. Para esa inclinaci ́on, Ho II cae en la posici ́on correcta en la relaci ́on de Tully-Fisher bar i ́onica y, adem ́as, su curva de rotaci ́on es congruente con MOND. Sin embargo, el an ́alisi s de estabilidad correspondiente indica que esta galaxia podr ́ıa ser problem ́atica para MOND porque las partes externas de esta galaxia ser ́ıan marginalmente inest ables bajo esa teor ́ıa de gravedad. Se requieren simulaciones num ́ericas de las galaxias enanas ricas en gas para ver la factibilidad de MOND.

  5. On the Borders: The Arrival of Irregular Immigrants in Malta--Some Implications for Education

    Science.gov (United States)

    Mercieca, Duncan

    2007-01-01

    This paper concerns the issue of the continual arrival of irregular immigrants in Malta and the problems that ensue. The view generally held is that we need to respond to the needs of irregular immigrants by providing services. However, with reference to some of Jacques Derrida's ideas, I argue in this paper that the "other"/immigrant is not there…

  6. On the Distinction between Regular and Irregular Inflectional Morphology: Evidence from Dinka

    Science.gov (United States)

    Ladd, D. Robert; Remijsen, Bert; Manyang, Caguor Adong

    2009-01-01

    Discussions of the psycholinguistic significance of regularity in inflectional morphology generally deal with languages in which regular forms can be clearly identified and revolve around whether there are distinct processing mechanisms for regular and irregular forms. We present a detailed description of Dinka's notoriously irregular noun number…

  7. Breaking Down Anonymity: Digital surveillance on irregular migrants in Germany and the Netherlands

    NARCIS (Netherlands)

    D.W.J. Broeders (Dennis)

    2009-01-01

    textabstractThe presence of irregular migrants causes a tough problem for policy makers. Political and popular aversion against the presence of irregular migrants has mounted in most West-European societies for years, yet their presence remains. Their exact numbers are obviously unknown - only

  8. Crime among irregular immigrants and the influence of internal border control

    NARCIS (Netherlands)

    A.S. Leerkes (Arjen); G.B.M. Engbersen (Godfried); J.P. van der Leun (Joanne)

    2012-01-01

    textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular

  9. Crime among irregular immigrants and the influence of internal border control

    NARCIS (Netherlands)

    Leerkes, A.S.; Engbersen, G.; Leun, van der J.P.

    2012-01-01

    Abstract Both the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants

  10. Design and Analysis of Printed Reflectarrays with Irregularly Positioned Array Elements

    DEFF Research Database (Denmark)

    Zhou, Min; Sørensen, Stig; Meincke, Peter

    2012-01-01

    and an irregular layout, generating the same contoured beam pattern to cover an European region with cross-polar and sidelobe suppression have been designed. Simulations show that better performance in the cross-polar radiation can be obtained by using the irregular reflectarray, thus demonstrating the potential...

  11. The Analysis of Frequency Reuse Irregular Patterns in Mobile Telephone Network

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Some frequency reuse irregular patterns in radionetwork design are proposed,the characteristic and applica-tion measures of these patterns are analyzed.Then this paperaccounts that frequency reuse irregular patterns is a usefulway to impove spectrum efficiency and it is significative forartificial intelligence to be applied in this field.

  12. Breaking Down Anonymity: Digital surveillance on irregular migrants in Germany and the Netherlands

    NARCIS (Netherlands)

    D.W.J. Broeders (Dennis)

    2009-01-01

    textabstractThe presence of irregular migrants causes a tough problem for policy makers. Political and popular aversion against the presence of irregular migrants has mounted in most West-European societies for years, yet their presence remains. Their exact numbers are obviously unknown - only estim

  13. Are irregular hypoechoic breast masses on ultrasound always malignancies?: A Pictorial essay

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youe Ree; Kim, Hun Soo; Kim, Hye Won [Wonkwang University Hospital, Iksan (Korea, Republic of)

    2015-12-15

    Irregular hypoechoic masses in the breast do not always indicate malignancies. Many benign breast diseases present with irregular hypoechoic masses that can mimic carcinoma on ultrasonography. Some of these diseases such as inflammation and trauma-related breast lesions could be suspected from a patient's symptoms and personal history. Careful ultrasonographic examination and biopsy could help to differentiate these from malignancies.

  14. Shear Wave Propagation in Multilayered Medium including an Irregular Fluid Saturated Porous Stratum with Rigid Boundary

    Directory of Open Access Journals (Sweden)

    Ravinder Kumar

    2014-01-01

    Full Text Available The present investigation is concerned with the study of propagation of shear waves in an anisotropic fluid saturated porous layer over a semi-infinite homogeneous elastic half-space lying under an elastic homogeneous layer with irregularity present at the interface with rigid boundary. The rectangular irregularity has been taken in the half-space. The dispersion equation for shear waves is derived by using the perturbation technique followed by Fourier transformation. Numerically, the effect of irregularity present is analysed. It is seen that the phase velocity is significantly influenced by the wave number and the depth of the irregularity. The variations of dimensionless phase velocity against dimensionless wave number are shown graphically for the different size of rectangular irregularities with the help of MATLAB.

  15. THE EQUIVALENT SLOPE - A NEW METHOD FOR CALCULATING SOIL LOSS FROM IRREGULAR SLOPES

    Institute of Scientific and Technical Information of China (English)

    Xiaoguang ZHAO; Hui SHI; Ming'an SHAO

    2004-01-01

    The slopes in field conditions are always irregular, but the supposed uniform slopes are used in most erosion models. Some studies used several uniform slopes to approximate an irregular slope for estimating soil erosion. This approximation is both time-consuming and weak in physical insights. In this paper, the concept of equivalent slope is presented based on that runoff potential on uniform slope is equal to that of irregular slope, and the equivalent uniform slope is used to estimate soil erosion instead of the irregular slopes. The estimated results of slope-length factors for convex and concave slopes are consistent with those from the method of Foster and Wischmeier.The experiments in the southern part of the Loess Plateau in China confirmed the applicability of the present method. The method is simple and has, to some extent, clear physical meanings, and is applicable for estimating soil erosion from irregular slopes.

  16. Dynamic stability of passive dynamic walking on an irregular surface.

    Science.gov (United States)

    Su, Jimmy Li-Shin; Dingwell, Jonathan B

    2007-12-01

    Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; pwalking stability are related to each other and to risk of falling.

  17. K2 and Herschel/PACS photometry of irregular satellites

    Science.gov (United States)

    Pal, Andras; Kiss, Csaba; Molnar, Laszlo; Mueller, Thomas G.; Sarneczky, Krisztian; Szabo, Robert; Kiss, Laszlo L.; Szabo, Gyula M.

    2016-10-01

    The combination of optical and far-infrared photometric measurements yields an unambiguous method for characterizing the basic physical and surface properties of minor bodies in the Solar System. In principle, an object with a certain visible brightness can either be an object with a small but bright or a large but dim surface. To resolve this issue, conducting thermal emission measurements can also be acquired since both larger and dimmer objects have higher infrared radiations. In addition, the precise modelling of thermal emission should certainly take into account the rotation period of these bodies - otherwise the presence of surface thermal inertia can result in inaccurate conclusions regarding to the physical size and albedo.Since early 2014, Kepler Space Telescope surveys fields close to the Ecliptic in a framework of quarterly campaigns of the K2 initiative. This program makes possible to continuously observe Solar System bodies during this period of 80-90 days and hence provide an uninterrupted photometric series of moving Solar System objects down to the magnitude range of R = 23.5. This instrument hence an ideal observatory now for Solar System studies. Due to the fact that the expected rotational periods of these objects are commensurable to the diurnal characteristics of ground-based observations, such uninterrupted light curves are rather valuable for the accurate determination of rotational characteristics - including the physical rotation period, the amplitude and the confirmation of the presence of double- or multiple peaked features.In this presentation we summarize our results of current K2 and legacy Herschel/PACS observations regarding to some of the irregular satellites of Uranus and Neptune, namely Caliban, Sycorax, Prospero, Setebos and Nereid. By comparing these results with similar kind of observations for trans-Neptunian objects (see Kiss et al., this DPS meeting), one can conclude how the formation and evolution of the outer Solar

  18. THE MEASUREMENT METHODOLOGY IMPROVEMENT OF THE HORIZONTAL IRREGULARITIES IN PLAN

    Directory of Open Access Journals (Sweden)

    O. M. Patlasov

    2015-08-01

    Full Text Available Purpose. Across the track superstructure (TSS there are structures where standard approach to the decision on the future of their operation is not entirely correct or acceptable. In particular, it concerns the track sections which are sufficiently quickly change their geometric parameters: the radius of curvature, angle of rotation, and the like. As an example, such portions of TSS may include crossovers where their component is within the so-called connecting part, which at a sufficiently short length, substantially changes curvature. The estimation of the position in terms of a design on the basis of the existing technique (by the difference in the adjacent arrows bending is virtually impossible. Therefore it is proposed to complement and improve the methodology for assessing the situation of the curve in plan upon difference in the adjacent versine. Methodology. The possible options for measuring horizontal curves in the plan were analyzed. The most adequate method, which does not contradict existing on the criterion of the possibility of using established standards was determined. The ease of measurement and calculation was took into account. Findings. Qualitative and quantitative verification of the proposed and existing methods showed very good agreement of the measurement results. This gives grounds to assert that this methodology can be recommended to the workers of track facilities in the assessment of horizontal irregularities in plan not only curves, but also within the connecting part of switch congresses. Originality. The existing method of valuation of the geometric position of the curves in the plan was improved. It does not create new regulations, and all results are evaluated by existing norms. Practical value. The proposed technique makes it possible, without creating a new regulatory framework, to be attached to existing one, and expanding the boundaries of its application. This method can be used not only for ordinary curves

  19. Menstrual Irregularity and Musculoskeletal Injury in Female High School Athletes

    Science.gov (United States)

    Thein-Nissenbaum, Jill M.; Rauh, Mitchell J.; Carr, Kathleen E.; Loud, Keith J.; McGuine, Timothy A.

    2012-01-01

    Context: The female athlete triad describes the interrelatedness of energy availability, menstrual function, and bone density. Although associations between triad components and musculoskeletal injury (INJ) have been reported in collegiate athletes, limited information exists about menstrual irregularity (MI) and INJ in the high school population. Objective: To determine the prevalence of and relationship between MI and INJ in high school athletes. Design: Cross-sectional study. Setting: High schools. Patients or Other Participants: The sample consisted of 249 female athletes from 3 high schools who competed in 33 interscholastic, school-sponsored sport teams, dance teams, and cheerleading or pom-pon squad during the 2006–2007 school year. Each athlete remained on the roster throughout the season. Main Outcome Measure(s): Participants completed a survey regarding injury type, number of days of sport participation missed, and menstrual history in the past year. Results: The prevalences of MI and INJ were 19.7% and 63.1%, respectively. Athletes who reported MI sustained a higher percentage of severe injuries (missing ≥22 days of practice or competition) than did athletes who reported normal menses. Although the trend was not significant, athletes with MI were almost 3 times more likely to sustain an injury resulting in 7 or more days of time lost from sport (odds ratio = 2.7, 95% confidence interval = 0.8, 8.8) than those who sustained an injury resulting in 7 or fewer days of time lost. Conclusions: The incidences of MI and INJ in this high school population during the study period were high. Athletes who reported MI sustained a higher percentage of severe injuries than did athletes who reported normal menses. Education programs to increase knowledge and improve management of MI and its potential effects on injury in female high school athletes are warranted. PMID:22488233

  20. TINITALY/01: a new Triangular Irregular Network of Italy

    Directory of Open Access Journals (Sweden)

    M. T. Pareschi

    2007-06-01

    Full Text Available A new Digital Elevation Model (DEM of the natural landforms of Italy is presented. A methodology is discussed to build a DEM over wide areas where elevation data from non-homogeneous (in density and accuracy input sources are available. The input elevation data include contour lines and spot heights derived from the Italian Regional topographic maps, satellite-based global positioning system points, ground based and radar altimetry data. Owing to the great heterogeneity of the input data density, the DEM format that better preserves the original accuracy is a Triangular Irregular Network (TIN. A Delaunay-based TIN structure is improved by using the DEST algorithm that enhances input data by evaluating inferred break-lines. Accordingly to this approach, biased distributions in slopes and elevations are absent. To prevent discontinuities at the boundary between regions characterized by data with different resolution a cubic Hermite blending weight S-shaped function is adopted. The TIN of Italy consists of 1.39×109 triangles. The average triangle area ranges from 12 to about 13000 m2 accordingly to different morphologies and different sources. About 50% of the model has a local average triangle area <500 m2. The vertical accuracy of the obtained DEM is evaluated by more than 200000 sparse control points. The overall Root Mean Square Error (RMSE is less than 3.5 m. The obtained national-scale DEM constitutes an useful support to carry out accurate geomorphological and geological investigations over large areas. The problem of choosing the best step size in deriving a grid from a TIN is then discussed and a method to quantify the loss of vertical information is presented as a function of the grid step. Some examples of DEM application are outlined. Under request, an high resolution stereo image database of the whole Italian territory (derived from the presented DEM is available to browse via internet.

  1. Determining dynamic parameters of different-scale ionospheric irregularities over northern Siberia

    Science.gov (United States)

    Afraimovich, E. L.; Lipko, Y. V. Y. V.; Vugmeister, B. O.

    2000-01-01

    In 1995-1996, observations were carried out at Norilsk (geomagnetic latitude and longitude 64.2 degN and 160.4 degE) to determine dynamic parameters of irregularities in the high-latitude ionosphere. The short-baseline spaced-receiver method that has been implemented at the ionospheric facility of the Norilsk Integrated Magnetic-Ionospheric Station, provides a means of simultaneously measuring parameters of small-scale irregularities (spatial scale of 3-5 km) by the Similar-Fading Method (SFM), as well as of medium-scale irregularities (time scale of 10-30 min, spatial scale of hundreds of kilometres) by the Statistical Angle-of-arrival and Doppler Method (SADM). About 20 h of the observational data for the F2-layer under quiet geomagnetic conditions (Kp = 3) and about 15 h for the sporadic E-layer (Kp ~ 3) were processed. It has been found that the propagation directions and velocities of different-scale irregularities do not coincide. Small-scale irregularities of the F2-layer travel predominantly eastward or westward. The velocity of the F2-layer irregularities is about 100 m/s, and under disturbed conditions it is up to 200-250 m/s. Small-scale irregularities of the sporadic E-layer travel mostly in the northward direction. It is confirmed that the Es-layer is characterised by high velocities of the irregularities (as high as 1000 m/s). Medium-scale irregularities with periods in the range of 10-30 min travel mostly in a southward direction with velocities of 20-40 m/s.

  2. Non-motile tetraploid spermatozoa of Misgurnus loach hybrids

    OpenAIRE

    Zhao, Yan; Fujimoto, Takafumi; Psenicka, Martin; Saito, Taiju; Arai, Katsutoshi

    2016-01-01

    We have compared various properties of spermatozoa from the wild diploid male pond loach Misgurnus anguillicaudatus to those from the interspecific male hybrid of the cross between a female M. anguillicaudatus and a male mud loach M. mizolepis. Our results show that spermatozoa from this interspecific hybrid had poor motility, low viability, abnormal morphology, a larger volume of mitochondrial mass per cell and higher ATP content of spermatozoa with tetraploid DNA content, and they were pres...

  3. The dynamics of rings around small, irregular bodies

    Science.gov (United States)

    Sicardy, Bruno

    2017-06-01

    Stellar occultations revealed the presence of two dense rings around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 508, 72, 2014). This is the first ring system discovered around an object that is not a giant planet, suggesting that rings may exist around numerous bodies in the solar system. Chariklo's rings roughly reside at the outer limit of the Roche zone of the body. Moreover, the main ring has sharp edges, which call for the presence of putative shepherd satellites. Those characteristics give an image of Chariklo's rings that are rather similar, in terms of dynamics, to those surrounding the gaseous planets.An important difference exists, however, between giant planets and small bodies: the formers are highly axisymmetric, while the latters can support mass anomalies (eg surface topographic features) or non-spherical shapes (eg an ellipsoidal figure of equilibrium) that involve masses, relative to the body itself, as large as 10-4-10-3.We investigate the effect of non-axisymmetric terms in the potential of the body upon a collisional debris disk that initially surrounds a small irregular body. We show that the corotation points being maxima of energy, dissipative collisions remove the particles from the corotation zone over short time scales (< 106 years). Moreover, the Lindblad resonances inside the corotation radius create torques that drive the particles onto the surface of the central body. Conversely, the outer Lindblad resonances push the disk material beyond the outer 3/2 and 2/1 Lindblad resonances.Taking as an example Chariklo's ring system, for which recent data have been obtained from stellar occultations, we show that the Lindblad resonant torques actuate over short time scales (< 106 years). This general picture offers a natural explanation of the presence of dense rings at the outer limit of Chariklo's Roche zone, and their absence closer to the body.The work leading to this results has received funding from the European

  4. Shape reconstruction of irregular bodies with multiple complementary data sources

    Science.gov (United States)

    Kaasalainen, M.; Viikinkoski, M.; Carry, B.; Durech, J.; Lamy, P.; Jorda, L.; Marchis, F.; Hestroffer, D.

    2011-10-01

    Irregularly shaped bodies with at most partial in situ data are a particular challenge for shape reconstruction and mapping. We have created an inversion algorithm and software package for complementary data sources, with which it is possible to create shape and spin models with feature details even when only groundbased data are available. The procedure uses photometry, adaptive optics or other images, occultation timings, and interferometry as main data sources, and we are extending it to include range-Doppler radar and thermal infrared data as well. The data sources are described as generalized projections in various observable spaces [2], which allows their uniform handling with essentially the same techniques, making the addition of new data sources inexpensive in terms of computation time or software development. We present a generally applicable shape support that can be automatically used for all surface types, including strongly nonconvex or non-starlike shapes. New models of Kleopatra (from photometry, adaptive optics, and interferometry) and Hermione are examples of this approach. When using adaptive optics images, the main information from these is extracted from the limb and terminator contours that can be determined much more accurately than the image pixel brightnesses that inevitably contain large errors for most targets. We have shown that the contours yield a wealth of information independent of the scattering properties of the surface [3]. Their use also facilitates a very fast and robustly converging algorithm. An important concept in the inversion is the optimal weighting of the various data modes. We have developed a mathematicallly rigorous scheme for this purpose. The resulting maximum compatibility estimate [3], a multimodal generalization of the maximum likelihood estimate, ensures that the actual information content of each source is properly taken into account, and that the resolution scale of the ensuing model can be reliably estimated

  5. Target Tracking of a Linear Time Invariant System under Irregular Sampling

    Directory of Open Access Journals (Sweden)

    Jin Xue-Bo

    2012-11-01

    Full Text Available Due to event-triggered sampling in a system, or maybe with the aim of reducing data storage, tracking many applications will encounter irregular sampling time. By calculating the matrix exponential using an inverse Laplace transform, this paper transforms the irregular sampling tracking problem to the problem of tracking with time-varying parameters of a system. Using the common Kalman filter, the developed method is used to track a target for the simulated trajectory and video tracking. The results of simulation experiments have shown that it can obtain good estimation performance even at a very high irregular rate of measurement sampling time.

  6. The effects of magnetic storm phases on F-layer irregularities from auroral to equatorial latitudes

    Science.gov (United States)

    Aarons, Jules; Mendillo, Michael

    1990-12-01

    Some topics of discussion in this journal include the following: The effects of electric field and ring current energy increases on F-layer irregularities at auroral and sub-auroral latitudes; The role of the ring current in generating or inhibiting equatorial F-layer irregularities during magnetic storms; Auroral and sub-auroral F-layer irregularities and high plasma convection during the magnetically active periods of September 17-24, 1984; and Simultaneous All-Sky Optical Airglow Imaging Observations and San Marco Satellite Measurements in the Pacific Sector.

  7. Monolingual and Bilingual Recognition of Regular and Irregular English Verbs: Sensitivity to Form Similarity Varies with First Language Experience

    Science.gov (United States)

    Basnight-Brown, Dana M.; Chen, Lang; Hua, Shu; Kostic, Aleksandar; Feldman, Laurie Beth

    2007-01-01

    We used a cross-modal priming procedure to explore the processing of irregular and regular English verb forms in both monolinguals and bilinguals (Serbian-English, Chinese-English). Materials included irregular nested stem (drawn-DRAW), irregular change stem (ran-RUN), and regular past tense-present tense verb pairs that were either low…

  8. Regular and Irregular Boundary Conditions in the AdS/CFT Correspondence

    CERN Document Server

    Mück, W

    1999-01-01

    We expand on Klebanov and Witten's recent proposal for formulating the AdS/CFT correspondence using irregular boundary conditions. The proposal is shown to be correct to any order in perturbation theory.

  9. On Impulsive Boundary Value Problems of Fractional Differential Equations with Irregular Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Guotao Wang

    2012-01-01

    Full Text Available We study nonlinear impulsive differential equations of fractional order with irregular boundary conditions. Some existence and uniqueness results are obtained by applying standard fixed-point theorems. For illustration of the results, some examples are discussed.

  10. Unified theory of type I and type II irregularities in the equatorial electrojet

    Science.gov (United States)

    Sudan, R. N.

    1983-01-01

    A nonlinear unified theory of type I and II irregularities is presented that explains their principal observed characteristics. The power spectrum is predicted by using Kolmogoroff-type conservation law for the power flow in cascading eddies.

  11. SCION: CubeSat Mission Concept to Observe Midlatitude Small-Scale Irregularities and Scintillation

    Science.gov (United States)

    Heine, T.; Moldwin, M.

    2014-12-01

    The SCintillation and Ionospheric Occultation NanoSats (SCION) mission concept is to deploy two low-cost CubeSat spacecraft that maintain a separation distance measure scintillation and associated small-scale density irregularities in the midlatitude ionosphere. Each spacecraft is equipped with a dual frequency GPS receiver to measure total electron content (TEC) and the S4 scintillation index along raypaths from the receiver to the GPS constellation. Scintillation causing small-scale density irregularities are increasingly observed in the vicinity of large TEC gradients associated with storm enhanced density (SED) regions. Detection of irregularities of the scale that cause GPS and VHF scintillation has previously relied on assumptions about their structural stability and drift speed. Space-based, multipoint observations would provide broad, regional coverage and disambiguation of temporal and spatial density fluctuations in order to detect small-scale irregularities without these assumptions.

  12. The encoding of temporally irregular and regular visual patterns in the human brain.

    Directory of Open Access Journals (Sweden)

    Semir Zeki

    Full Text Available In the work reported here, we set out to study the neural systems that detect predictable temporal patterns and departures from them. We used functional magnetic resonance imaging (fMRI to locate activity in the brains of subjects when they viewed temporally regular and irregular patterns produced by letters, numbers, colors and luminance. Activity induced by irregular sequences was located within dorsolateral prefrontal cortex, including an area that was responsive to irregular patterns regardless of the type of visual stimuli producing them. Conversely, temporally regular arrangements resulted in activity in the right frontal lobe (medial frontal gyrus, in the left orbito-frontal cortex and in the left pallidum. The results show that there is an abstractive system in the brain for detecting temporal irregularity, regardless of the source producing it.

  13. Periodic Orbit Families in the Gravitational Field of Irregular-shaped Bodies

    CERN Document Server

    Jiang, Yu

    2016-01-01

    The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies, and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been f...

  14. EVALUATION OF SEISMIC BEHAVIOR OF IRREGULAR TUBE BUILDINGS IN TUBE SYSTEMS

    Directory of Open Access Journals (Sweden)

    Hojat Allah Ghasemi

    2016-03-01

    Full Text Available Setbacks in the volume of a building usually arise from the demands of urban design for illumination, proportion, etc. However, in seismic events they are the cause of abrupt changes in stiffness and mass producing a concentration of stresses in the floors near the site of sudden change. In general terms, one should ensure that the transitions are as gradual as possible in order to avoid such concentration of stresses. This study is intended to investigate seismic behavior of irregular building tube in tube systems, for this purpose seismic behavior of 40-story and 60-story reinforced concrete frame building with irregular plan was evaluated, seismic behavior of irregular buildings was assessed by overall building drifts, story drifts and shear lag behavior factors.. Higher irregularities in the overall plan structure of a building increase the phenomena of story drift and shear lag phenomena. Story drift and shear lag are higher for 60-story building than for a 40-story building.

  15. Irregular singularities in Liouville theory and Argyres-Douglas type gauge theories, I

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotto, D. [Institute for Advanced Study (IAS), Princeton, NJ (United States); Teschner, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-03-15

    Motivated by problems arising in the study of N=2 supersymmetric gauge theories we introduce and study irregular singularities in two-dimensional conformal field theory, here Liouville theory. Irregular singularities are associated to representations of the Virasoro algebra in which a subset of the annihilation part of the algebra act diagonally. In this paper we define natural bases for the space of conformal blocks in the presence of irregular singularities, describe how to calculate their series expansions, and how such conformal blocks can be constructed by some delicate limiting procedure from ordinary conformal blocks. This leads us to a proposal for the structure functions appearing in the decomposition of physical correlation functions with irregular singularities into conformal blocks. Taken together, we get a precise prediction for the partition functions of some Argyres-Douglas type theories on S{sup 4}. (orig.)

  16. Irregular Wave Forces on Monopile Foundations. Effect af Full Nonlinearity and Bed Slope

    DEFF Research Database (Denmark)

    Schløer, Signe; Bredmose, Henrik; Bingham, Harry B.

    2011-01-01

    Forces on a monopile from a nonlinear irregular unidirectional wave model are investigated. Two seabed profiles of different slopes are considered. Morison’s equation is used to investigate the forcing from fully nonlinear irregular waves and to compare the results with those obtained from linear...... wave theory and with stream function wave theory. The latter of these theories is only valid on a flat bed. The three predictions of wave forces are compared and the influence of the bed slope is investigated. Force-profiles of two selected waves from the irregular wave train are further compared...... with the corresponding forceprofiles from stream function theory. The results suggest that the nonlinear irregular waves give rise to larger extreme wave forces than those predicted by linear theory and that a steeper bed slope increases the wave forces both for linear and nonlinear waves. It is further found...

  17. Stochastic analysis model for vehicle-track coupled systems subject to earthquakes and track random irregularities

    Science.gov (United States)

    Xu, Lei; Zhai, Wanming

    2017-10-01

    This paper devotes to develop a computational model for stochastic analysis and reliability assessment of vehicle-track systems subject to earthquakes and track random irregularities. In this model, the earthquake is expressed as non-stationary random process simulated by spectral representation and random function, and the track random irregularities with ergodic properties on amplitudes, wavelengths and probabilities are characterized by a track irregularity probabilistic model, and then the number theoretical method (NTM) is applied to effectively select representative samples of earthquakes and track random irregularities. Furthermore, a vehicle-track coupled model is presented to obtain the dynamic responses of vehicle-track systems due to the earthquakes and track random irregularities at time-domain, and the probability density evolution method (PDEM) is introduced to describe the evolutionary process of probability from excitation input to response output by assuming the vehicle-track system as a probabilistic conservative system, which lays the foundation on reliability assessment of vehicle-track systems. The effectiveness of the proposed model is validated by comparing to the results of Monte-Carlo method from statistical viewpoint. As an illustrative example, the random vibrations of a high-speed railway vehicle running on the track slabs excited by lateral seismic waves and track random irregularities are analyzed, from which some significant conclusions can be drawn, e.g., track irregularities will additionally promote the dynamic influence of earthquakes especially on maximum values and dispersion degree of responses; the characteristic frequencies or frequency ranges respectively governed by earthquakes and track random irregularities are greatly different, moreover, the lateral seismic waves will dominate or even change the characteristic frequencies of system responses of some lateral dynamic indices at low frequency.

  18. Association between sleep duration and menstrual cycle irregularity in Korean female adolescents.

    Science.gov (United States)

    Nam, Ga Eun; Han, Kyungdo; Lee, Gyungjoo

    2017-07-01

    The association between sleep and the menstrual cycle in the adolescent population has been scarcely studied. This study aimed to investigate the association between sleep duration and menstrual cycle irregularity among female adolescents using nationwide representative data from the South Korean population. This population-based, cross-sectional study used the data collected from Korea National Health and Nutrition Examination Survey 2010-2012, and the data from 801 female adolescents were analyzed. Hierarchical multivariable logistic regression analysis was performed to assess the risk of menstrual cycle irregularity in relation to sleep duration. Subjects with menstrual cycle irregularity accounted for 15% (N = 120). The mean sleep duration in subjects with menstrual cycle irregularity was significantly shorter than that in those without (p = 0.003). Menstrual cycle irregularity prevalence tended to decrease as sleep duration increased (p for trend = 0.004), which was significantly different based on sleep duration and presence of depressive mood (p = 0.011). Sleep duration ≤5 h per day was significantly associated with increased risk of menstrual cycle irregularity compared with that in the subjects whose sleep duration is ≥8 h per day even after adjusting for confounding variables. The odds ratios of menstrual cycle irregularity tended to increase for shorter sleep duration in all adjusted models. This study found a significant inverse association between sleep duration and menstrual cycle irregularity among Korean female adolescents. Increasing sleep duration is required to improve the reproductive health of female adolescents. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS

    Science.gov (United States)

    Wautelet, Gilles; Warnant, René

    2014-03-01

    High-frequency variability of the ionosphere, or irregularities, constitutes the main threat for real-time precise positioning techniques based on Global Navigation Satellite Systems (GNSS) measurements. Indeed, during periods of enhanced ionospheric variability, GNSS users in the field—who cannot verify the integrity of their measurements—will experience positioning errors that can reach several decimeters, while the nominal accuracy of the technique is cm-level. In the frame of this paper, a climatological analysis of irregularities over the European mid-latitude region is presented. Based on a 10 years GPS dataset over Belgium, the work analyzes the occurrence rate (as a function of the solar cycle, season and local time) as well as the amplitude of ionospheric irregularities observed at a single GPS station. The study covers irregularities either due to space weather events (solar origin) or of terrestrial origin. If space weather irregularities are responsible for the largest effects in terms of ionospheric error, their occurrence rate highly depends on solar activity. Indeed, the occurrence rate of ionospheric irregularities is about 9 % during solar maximum, whereas it drops to about 0 % during medium or low solar activity periods. Medium-scale ionospheric disturbances (MSTIDs) occurring during daytime in autumn/winter are the most recurrent pattern of the time series, with yearly proportions slightly varying with the solar cycle and an amplitude of about 10 % of the TEC background. Another recurrent irregularity type, though less frequent than MSTIDs, is the noise-like variability in TEC observed during summer nighttime, under quiet geomagnetic conditions. These summer nighttime irregularities exhibit amplitudes ranging between 8 and 15 % of the TEC background.

  20. Dynamics of landslides on comets of irregular shape

    Science.gov (United States)

    Czechowski, Leszek

    2017-04-01

    Landslides were observed on a few comet's nuclei, e.g. [1], [2]. The mechanism of their origin is not obvious because of very low gravity. According to [2] fluidization and multiphase transport of cometary material could be an explanation. We investigate here motion of the mass on a comet of irregular shape. The mechanism responsible for the low friction is not considered here. In fact, mass motion often occurs without contact with the surface. The motion could be triggered by meteoroids impacts or by the tidal forces. Comets nuclei are believed to be built of soft materials like snow and dust. The landing of Philae on the comet 67P/Czuriumow-Gierasimienko indicates a different situation. According to [1]: "thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength". Here we assume that elastic properties of comet's nuclei could be similar to elastic properties of dry snow, namely Young modulus is assumed to be 1 - 100 MPa, see [3] and [4]. We consider nucleus of the shape of 67P/Churyumov-Gerasimenko with density 470 kg/m3. The impact or tidal forces result in changing of rotation of the comet. In general, the vector of angular velocity will be a subject to nutation that results in changing of centrifugal force, and consequently could be a factor triggering landslides. Note that nucleus' shape does not resemble the shape of surface of constant value of gravitational potential (i.e. 'geoid'). Our numerical models indicate the parts of the nucleus where landslides start and other parts where landslides stop. Of course, the regolith from the first type of regions would be removed to the regions of the second class. The motion of the mass is often complicated because of complicated distribution of the gravity and complicated shape of the nucleus. Acknowledgement: The research is partly supported by Polish National Science Centre

  1. Experimental Investigation of Wave-Induced Hydroelastic Vibrations of Trimaran in Oblique Irregular Waves

    Directory of Open Access Journals (Sweden)

    Haoyun Tang

    2016-01-01

    Full Text Available The irregular wave condition, especially the oblique irregular wave condition, is the actual circumstances when trimaran is sailing in sea. In order to identify the characteristic of the wave-induced hydroelastic vibration in irregular waves, as well as investigate the change of vibration in different oblique irregular wave conditions, trimaran model tests were conducted to measure vibrations, wave impact, and motion under different azimuth and wave height. The vibration on main hull, side hull, and cross-desk is measured and analyzed separately to observe the influence of irregular wave in different structural parts. The longitudinal vibration, transverse vibration, and torsion are also included in the model tests measurement to investigate the relationship between these vibration deformation components and parameters of the irregular waves. The wave-induced hydroelastic vibrations and whipping effect is extracted and analyzed to find influence of whipping and springing on the total vibration. Based on the analysis, the dangerous positions and the critical waves condition is introduced to ensure that the subsequent structural strength assessment is more reliable.

  2. Effects of surface irregularities on intensity data from laser scanning: an experimental approach.

    Directory of Open Access Journals (Sweden)

    G. Teza

    2008-06-01

    Full Text Available The results of an experiment carried out with the aim to investigate the role of surface irregularities on the intensity data provided by a terrestrial laser scanner (TLS survey are reported here. Depending on surface roughness, the interaction between an electromagnetic wave and microscopic irregularities leads to a Lambertian-like diffusive light reflection, allowing the TLS to receive the backscattered component of the signal. The described experiment consists in a series of TLS-based acquisitions of a rotating artificial target specifically conceived in order to highlight the effects on the intensity data due to surface irregularity. This target is articulated in a flat plate and in an irregular surface, whose macro-roughness has a characteristic length with the same order of the spot size. Results point out the different behavior of the plates. The intensity of the signal backscattered by the planar element decreases if the incidence angle increases, whereas the intensity of the signal backscattered by the irregular surface is almost constant if the incidence angle varies. Since the typical surfaces acquired in a geological/geophysical survey are generally irregular, these results imply that the intensity data can be easily used in order to evaluate the reflectance of the material at the considered wavelength, e.g. for pattern recognition purposes.

  3. Modification of transmission dose algorithm for irregularly shaped radiation field and tissue deficit

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyong Geon; Shin, Kyo Chul [Dankook Univ., College of Medicine, Seoul (Korea, Republic of); Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan [Seoul National Univ., College of Medicine, Seoul (Korea, Republic of); Lee, Hyoung Koo [The Catholic Univ., College of Medicine, Seoul (Korea, Republic of)

    2002-07-01

    Algorithm for estimation of transmission dose was modified for use in partially blocked radiation fields and in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of beam block. And an algorithm for correction of transmission dose in cases of partially blocked radiation field was developed from the measured data. The algorithm was tested in some clinical settings with irregular shaped field. Also, another algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. This algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients by using multiple sheets of solid phantoms. The algorithm for correction of beam block could accurately reflect the effect of beam block, with error within {+-}1.0%, both with square fields and irregularly shaped fields. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within {+-}1.0% in most situations and within {+-}3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithms could accurately estimate the transmission dose in most radiation treatment settings including irregularly shaped field and irregularly shaped body contour with tissue deficit in transmission dosimetry.

  4. Design and development of LED-based irregular leather area measuring machine

    Science.gov (United States)

    Adil, Rehan; Khan, Sarah Jamal

    2012-01-01

    Using optical sensor array, a precision motion control system in a conveyer follows the irregular shaped leather sheet to measure its surface area. In operation, irregular shaped leather sheet passes on conveyer belt and optical sensor array detects the leather sheet edge. In this way outside curvature of the leather sheet is detected and is then feed to the controller to measure its approximate area. Such system can measure irregular shapes, by neglecting rounded corners, ellipses etc. To minimize the error in calculating surface area of irregular curve to the above mentioned system, the motion control system only requires the footprint of the optical sensor to be small and the distance between the sensors is to be minimized. In the proposed technique surface area measurement of irregular shaped leather sheet is done by defining velocity and detecting position of the move. The motion controller takes the information and creates the necessary edge profile on point-to-point bases. As a result irregular shape of leather sheet is mapped and is then feed to the controller to calculate surface area.

  5. Characterizing neural activities evoked by manual acupuncture through spiking irregularity measures

    Science.gov (United States)

    Xue, Ming; Wang, Jiang; Deng, Bin; Wei, Xi-Le; Yu, Hai-Tao; Chen, Ying-Yuan

    2013-09-01

    The neural system characterizes information in external stimulations by different spiking patterns. In order to examine how neural spiking patterns are related to acupuncture manipulations, experiments are designed in such a way that different types of manual acupuncture (MA) manipulations are taken at the ‘Zusanli’ point of experimental rats, and the induced electrical signals in the spinal dorsal root ganglion are detected and recorded. The interspike interval (ISI) statistical histogram is fitted by the gamma distribution, which has two parameters: one is the time-dependent firing rate and the other is a shape parameter characterizing the spiking irregularities. The shape parameter is the measure of spiking irregularities and can be used to identify the type of MA manipulations. The coefficient of variation is mostly used to measure the spike time irregularity, but it overestimates the irregularity in the case of pronounced firing rate changes. However, experiments show that each acupuncture manipulation will lead to changes in the firing rate. So we combine four relatively rate-independent measures to study the irregularity of spike trains evoked by different types of MA manipulations. Results suggest that the MA manipulations possess unique spiking statistics and characteristics and can be distinguished according to the spiking irregularity measures. These studies have offered new insights into the coding processes and information transfer of acupuncture.

  6. New prospective 4D-CT for mitigating the effects of irregular respiratory motion

    Science.gov (United States)

    Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

    2017-08-01

    Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

  7. A Radio Propagation Technique for Geolocating Ionospheric Irregularities along Radio Occultation Ray-Paths

    Science.gov (United States)

    Carrano, C. S.; Groves, K. M.; Rino, C. L.; McNeil, W. J.

    2016-12-01

    Radio occultations (RO) with Global Navigation Satellite System (GNSS) signas have been widely used for remote sensing of tropospheric parameters and to provide ionospheric electron density profiles for the purpose of improving terrestrial and space weather forecasts. Radio occultations have also been used to investigate the morphology of irregularities that cause radio wave scintillation. Spaced-based monitoring of ionospheric irregularities is advantageous because it can be performed continuously and globally, including over ocean regions not easily monitored with ground-based instruments. Nevertheless, the radio propagation path of an occultation through the ionosphere can be very long (up to several thousand km), such that it can be challenging to infer the geographic location and extent of the irregularities from the scintillations they produce. Unlike RO retrievals of slant TEC which are dominated by the contribution near the tangent point, scintillations can be generated by irregularities distributed anywhere along the propagation path between transmitting and receiving satellites. In this paper, we propose a new technique for characterizing and geolocating ionospheric irregularities using radio occultation observations of amplitude scintillation. The approach taken is to solve an inverse problem for the propagation of radio waves through a phase changing screen. Referred to as Irregularity Parameter Estimation (Carrano and Rino, Radio Sci, 2016), this inverse technique estimates the irregularity turbulence strength, spectral index, and Fresnel frequency from measurements of amplitude scintillation. A new model for the effective velocity at which the radio occultation ray-path scans through the irregularity region is used to map the estimated Fresnel frequency to Fresnel spatial scale, which yields the distance from the receiver to the irregularities. Additional geophysical factors such as apex altitude and background electron density along the ray-path can

  8. SU-C-210-03: Impact of Breathing Irregularities On Gated Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Schiuma, D; Arheit, M; Schmelzer, P; Scheib, S [Varian Medical Systems, Imaging Laboratory GmbH, Baden-Daettwil (Switzerland); Buchsbaum, T; Pemler, P [Radioonkologie, Stadtspital Triemli, Zurich (Switzerland)

    2015-06-15

    Purpose: To evaluate the effect of breathing irregularities on target location in gated treatments using amplitude and phase gating. Methods: 111 breathing patterns acquired using RPM system were categorized based on period and amplitude STD as regular (STD period ≤ 0.5 s, STD amplitude ≤ 1.5 mm), medium (0.5 s < STD period ≤ 1 s, 1.5 mm < STD amplitude ≤ 3 mm) and irregular (STD period > 1 s, STD amplitude > 3 mm). One pattern representative of the average defined population was selected per category and corresponding target motion reproduced using Quasar Respiratory Motion Phantom. Phantom in motion underwent 4D-CT scan with phase reconstruction. Gated window was defined at end of exhale and DRRs reconstructed in treatment planning at 40% (beam on) and 60% phase (beam off). Target location uncertainty was assessed by comparing gated kV triggered images continuously acquired at beam on/off on a True Beam 2.0 with corresponding DRRs. Results: Average target uncertainty with amplitude gating was in [0.4 – 1.9] mm range for the different scenarios with maximum STD of 1.2 mm for the irregular pattern. Average target uncertainty with phase gating was [1.1 – 2.2] mm for regular and medium patterns, while it increased to [3.6 – 9.6] mm for the irregular pattern. Live gated motion was stable with amplitude gating, while increasing with phase gating for the irregular pattern. Treatment duration range was [68 – 160] s with amplitude and [70 – 74] s with phase gating. Conclusion: Breathing irregularities were found to affect gated treatments only when using phase gating. For regular and medium patterns no significant difference was found between the two gating strategies. Amplitude gating ensured stable gated motion within the different patterns, thus reducing intra-fraction target location variability for the irregular pattern and resulting in longer treatment duration.

  9. Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers.

    Science.gov (United States)

    Marqueze, Elaine Cristina; Ulhôa, Melissa Araújo; Moreno, Claudia Roberta de Castro

    2013-06-01

    To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p physical activity.

  10. Optimizing Chinese character displays improves recognition and reading performance of simulated irregular phosphene maps.

    Science.gov (United States)

    Lu, Yanyu; Kan, Han; Liu, Jie; Wang, Jing; Tao, Chen; Chen, Yao; Ren, Qiushi; Hu, Jie; Chai, Xinyu

    2013-04-26

    A visual prosthesis may elicit an irregular phosphene map relative to a regular electrode array. This study used simulated irregular phosphene maps as a way of optimizing the display methods of Chinese characters (CCs) to improve recognition and reading performance. TWENTY SUBJECTS WITH NORMAL OR CORRECTED SIGHT PARTICIPATED IN TWO EXPERIMENTS (9 FEMALES, 11 MALES, 2030 YEARS OF AGE). EXPERIMENT 1: two character display methods were proposed: selecting phosphenes covered by character strokes on a simulated phosphene array (projection method) and finding the phosphene closest to the expected location in some range of an irregular phosphene array as a substitute (nearest neighbor search [NNS] method). The recognition accuracy of CCs was investigated using six levels for the coverage ratio of stroke and phosphene area and for search range, respectively, for two methods, for several irregularity levels. Experiment 2: reading accuracy (RA) and reading efficiency (RE) were measured using the regular array correspondence and NNS methods. EXPERIMENT 1: projection and NNS methods were significantly affected by coverage ratio or search range. NNS significantly improved CC recognition accuracy to the highest at 81.3 ± 2.7% and 59.1 ± 5.2%, respectively, for different irregularity levels, compared with the projection method. Experiment 2: RA and RE significantly decreased as the distortion level increased; NNS significantly improved RA (from approximately 40% to >80%) and RE (from approximately 13 char/min to >40 char/min) when reading more irregular paragraphs. The performance of CC recognition and paragraph reading when using an irregular phosphene array can be improved through optimizing the display method.

  11. SEISMIC PROPAGATION SIMULATION IN COMPLEX MEDIA WITH NON-RECTANGULAR IRREGULAR-GRID FINITE-DIFFERENCE

    Institute of Scientific and Technical Information of China (English)

    SUN Weitao; YANG Huizhu

    2004-01-01

    This paper presents a finite-difference (FD) method with spatially non-rectangular irregular grids to simulate the elastic wave propagation. Staggered irregular grid finite difference operators with a second-order time and spatial accuracy are used to approximate the velocity-stress elastic wave equations. This method is very simple and the cost of computing time is not much. Complicated geometries like curved thin layers, cased borehole and nonplanar interfaces may be treated with nonrectangular irregular grids in a more flexible way. Unlike the multi-grid scheme, this method requires no interpolation between the fine and coarse grids and all grids are computed at the same spatial iteration. Compared with the rectangular irregular grid FD, the spurious diffractions from "staircase"interfaces can easily be eliminated without using finer grids. Dispersion and stability conditions of the proposed method can be established in a similar form as for the rectangular irregular grid scheme. The Higdon's absorbing boundary condition is adopted to eliminate boundary reflections. Numerical simulations show that this method has satisfactory stability and accuracy in simulating wave propagation near rough solid-fluid interfaces. The computation costs are less than those using a regular grid and rectangular grid FD method.

  12. W_3 irregular states and isolated N=2 superconformal field theories

    CERN Document Server

    Kanno, Hiroaki; Shiba, Shotaro; Taki, Masato

    2013-01-01

    We explore the proposal that the six-dimensional (2,0) theory on the Riemann surface with irregular punctures leads to a four-dimensional gauge theory coupled to the isolated N=2 superconformal theories of Argyres-Douglas type, and to two-dimensional conformal field theory with irregular states. Following the approach of Gaiotto-Teschner for the Virasoro case, we construct W_3 irregular states by colliding a single SU(3) puncture with several regular punctures of simple type. If n simple punctures are colliding with the SU(3) puncture, the resulting irregular state is a simultaneous eigenvector of the positive modes L_n, ..., L_{2n} and W_{2n}, ..., W_{3n} of the W_3 algebra. We find the corresponding isolated SCFT with an SU(3) flavor symmetry as a nontrivial IR fixed point on the Coulomb branch of the SU(3) linear quiver gauge theories, by confirming that its Seiberg-Witten curve correctly predicts the conditions for the W_3 irregular states. We also show that these SCFT's are identical to the ones obtained...

  13. {{{W}}_3} irregular states and isolated {N}=2 superconformal field theories

    Science.gov (United States)

    Kanno, Hiroaki; Maruyoshi, Kazunobu; Shiba, Shotaro; Taki, Masato

    2013-03-01

    We explore the proposal that the six-dimensional (2, 0) theory on the Riemann surface with irregular punctures leads to a four-dimensional gauge theory coupled to the isolated {N}=2 superconformal theories of Argyres-Douglas type, and to two-dimensional conformal field theory with irregular states. Following the approach of Gaiotto-Teschner for the Virasoro case, we construct {{{W}}_3} irregular states by colliding a single SU(3) puncture with several regular punctures of simple type. If n simple punctures are colliding with the SU(3) puncture, the resulting irregular state is a simultaneous eigenvector of the positive modes L n , . . . , L 2 n and W 2 n , . . . , W 3 n of the {{{W}}_3} algebra. We find the corresponding isolated SCFT with an SU(3) flavor symmetry as a nontrivial IR fixed point on the Coulomb branch of the SU(3) linear quiver gauge theories, by confirming that its Seiberg-Witten curve correctly predicts the conditions for the {{{W}}_3} irregular states. We also compare these SCFT's with the ones obtained from the BPS quiver method.

  14. 30 MHz radar observations of artificial E region field-aligned plasma irregularities

    Directory of Open Access Journals (Sweden)

    D. L. Hysell

    2008-02-01

    Full Text Available Artificial E region field aligned irregularities (FAIs have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid- and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

  15. Dispositional resilience as a moderator of the relationship between chronic stress and irregular menstrual cycle.

    Science.gov (United States)

    Palm-Fischbacher, Simona; Ehlert, Ulrike

    2014-06-01

    Menstrual-cycle irregularity may have an important influence on the subsequent development of chronic diseases. Several risk factors for irregular menstrual cycles have been detected, including stress. Our aim was to extend research on the link between chronic stress and menstrual-cycle irregularity and to assess potential protective factors, such as dispositional resilience, which we hypothesize to be associated with the maintenance or promotion of a healthy menstrual cycle. For this cross-sectional study, data on 696 healthy women aged 20-40 years were obtained. The women completed measures of chronic stress, dispositional resilience and menstrual-cycle irregularity. Furthermore, potential confounds were assessed. Of the participants, 383 (55%) reported no current use of hormonal contraceptives; 313 (45%) reported current use hormonal contraception and were included as a control group. The results suggest that in women not using hormonal contraception, chronic stress (OR = 1.05, 95%CI = 1.02-1.08, p = 0.001) and dispositional resilience (OR = 0.43, 95%CI = 0.31-0.59, p menstrual cycle regularity. In addition, women with greater dispositional resilience have reduced risk for irregular menstrual cycles in the face of low to moderate chronic stress; however, this association is changed at the highest level of chronic stress. These findings suggest that dispositional resilience may be a protective psychological trait that modulates reproductive functioning.

  16. Scintillation and irregularities from the nightside part of a Sun-aligned polar cap arc

    Science.gov (United States)

    Meeren, Christer; Oksavik, Kjellmar; Lorentzen, Dag A.; Paxton, Larry J.; Clausen, Lasse B. N.

    2016-06-01

    In this paper we study the presence of irregularities and scintillation in relation to the nightside part of a long-lived, Sun-aligned transpolar arc on 15 January 2015. The arc was observed in DMSP UV and particle data and lasted at least 3 h between 1700 and 2000 UT. The arc was more intense than the main oval during this time. From all-sky imagers on Svalbard we were able to study the evolution of the arc, which drifted slowly westward toward the dusk cell. The intensity of the arc as observed from ground was 10-17 kR in 557.7 nm and 2-3.5 kR in 630.0 nm, i.e., significant emissions in both green and red emission lines. We have used high-resolution raw data from global navigation satellite systems (GNSS) receivers and backscatter from Super Dual Auroral Radar Network (SuperDARN) radars to study irregularities and scintillation in relation to the polar cap arc. Even though the literature has suggested that polar cap arcs are potential sources for irregularities, our results indicate only very weak irregularities. This may be due to the background density in the northward IMF polar cap being too low for significant irregularities to be created.

  17. Morning Cortisol Levels and Perceived Stress in Irregular Shift Workers Compared with Regular Daytime Workers

    Directory of Open Access Journals (Sweden)

    Harri Lindholm

    2012-01-01

    Full Text Available The 24/7 work environment and irregular shifts may markedly enhance the psychological pressure of media work. Changes in the hypothalamic-pituitary-adrenal axis reflect adaptation to stress. We analysed the correlation between subjective stress, sleep, salivary cortisol, and melatonin hormones among Finnish media workers with regular daytime work (RDW and with irregular shift work (ISW while controlling confounders. From 874 employees with regular daytime work or with irregular shift work, 70 employees from both groups were randomly selected. The final number of employees with a complete salivary cortisol profile was 66 in the RDW group and 65 in the ISW group. Five saliva samples were gathered from each subject before and during a working day. The salivary cortisol level of the sample taken 60 minutes after awakening (T1 was compared to the salivary cortisol level taken immediately after awakening (T0, T1/T0 ratio. The ratio was higher in the ISW group than in RDW group. Irregular shift work (P<0.001, severe stress (P<0.05, and less sleep (P<0.05 were independently associated with an augmented cortisol response after awakening. A stressful work environment and irregular shift work enhance cortisol excretion after waking. In the long run, this may become detrimental to health.

  18. Method of determining effects of heat-induced irregular refractive index on an optical system.

    Science.gov (United States)

    Song, Xifa; Li, Lin; Huang, Yifan

    2015-09-01

    The effects of an irregular refractive index on optical performance are examined. A method was developed to express a lens's irregular refractive index distribution. An optical system and its mountings were modeled by a thermomechanical finite element (FE) program in the predicted operating temperature range, -45°C-50°C. FE outputs were elaborated using a MATLAB optimization routine; a nonlinear least squares algorithm was adopted to determine which gradient equation best fit each lens's refractive index distribution. The obtained gradient data were imported into Zemax for sequential ray-tracing analysis. The root mean square spot diameter, modulation transfer function, and diffraction ensquared energy were computed for an optical system under an irregular refractive index and under thermoelastic deformation. These properties are greatly reduced by the irregular refractive index effect, which is one-third to five-sevenths the size of the thermoelastic deformation effect. Thus, thermal analyses of optical systems should consider not only thermoelastic deformation but also refractive index irregularities caused by inhomogeneous temperature.

  19. Factors associated with irregular breakfast consumption among high school students in a Japanese community.

    Science.gov (United States)

    Oba, Shino; Oogushi, Kazuhiro; Ogata, Hiromitsu; Nakai, Hiromitsu

    2016-01-01

    This study evaluated the associations between the characteristics of high school students and irregular breakfast consumption and explored the association with knowledge regarding diet and dietary education in a community in Japan. A cross-sectional survey using a self-administered questionnaire was conducted in 2007 among all the high school students in the second grade in Imari, Saga. Data for 318 male and 292 female students were analyzed. Irregular breakfast consumption was defined as consuming breakfast three times or less in a week. The associations between the characteristics of students and irregular breakfast consumption were assessed using logistic regression with adjustments for sex and school. Among male students, a strong association between the consumption of juice or pop and irregular breakfast consumption was observed (OR comparing ">=2 servings" vs "rarely"=8.97, 95% CI=2.99-26.9). The associations with wake times and bed times were strong among male students, and the association with regular bowel movements was strong among female students. Students who had knowledge of regional agricultural and livestock products were more likely to consume breakfast regularly, and this association was significant among female students (OR=2.89, 95% CI=1.23-6.82). Significant associations were also observed with the consumption of snacks, and traditional greeting before meals. Several characteristics, including specific knowledge, were associated with the irregular consumption of breakfast. The results are of interest to policy makers, nutrition specialists, and educators working to enhance regular breakfast consumption among students.

  20. Análisis de la evolución temporal de las desigualdades con datos irregulares || Analyzing the Income Inequalities with Irregular Time Series

    Directory of Open Access Journals (Sweden)

    Callealta Barroso, Francisco Javier

    2012-01-01

    Full Text Available En este artículo se proporciona una herramienta que permite estudiar las distribuciones de renta en una población a lo largo del tiempo, sin importar que los datos se distribuyan de forma irregular. Incluso, se posibilita la aproximación de curvas de Lorenz en instantes en los que no se cuenta con los datos necesarios. Finalmente, se presenta un ejemplo de aplicación de la técnica en un país europeo en que las desigualdades son especialmente relevantes: España. || This article provides a tool to study over time the distributions of income in a population, regardless the irregular distribution of data. We even approach Lorenz curves at the times when we lack the required data. Finally we apply the present technique to a European country where inequalities are particularly relevant: Spain.

  1. Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

    CERN Document Server

    Gomes-Júnior, A R; Vieira-Martins, R; Arlot, J -E; Camargo, J I B; Braga-Ribas, F; Neto, D N da Silva; Andrei, A H; Dias-Oliveira, A; Morgado, B E; Benedetti-Rossi, G; Duchemin, Y; Desmars, J; Lainey, V; Thuillot, W

    2015-01-01

    The irregular satellites of the giant planets are believed to have been captured during the evolution of the solar system. Knowing their physical parameters, such as size, density, and albedo is important for constraining where they came from and how they were captured. The best way to obtain these parameters are observations in situ by spacecrafts or from stellar occultations by the objects. Both techniques demand that the orbits are well known. We aimed to obtain good astrometric positions of irregular satellites to improve their orbits and ephemeris. We identified and reduced observations of several irregular satellites from three databases containing more than 8000 images obtained between 1992 and 2014 at three sites (Observat\\'orio do Pico dos Dias, Observatoire de Haute-Provence, and European Southern Observatory - La Silla). We used the software PRAIA (Platform for Reduction of Astronomical Images Automatically) to make the astrometric reduction of the CCD frames. The UCAC4 catalog represented the Inte...

  2. Experimental Researches on Reflective and Transmitting Performances of Quarter Circular Breakwater Under Regular and Irregular Waves

    Institute of Scientific and Technical Information of China (English)

    SHI Yan-jiao; WU Mi-ling; JIANG Xue-lian; LI Yan-bao

    2011-01-01

    A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater (QCB) in comparison with those of semi-circular breakwater (SCB).Based on regular wave tests,the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated.Then,the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB.In irregular wave experiments,the reflection coefficients of QCB and their spectrums are studied.Finally,the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.

  3. Improved Multispanning Tree Routing Using Efficient and Reliable Routing Algorithm for Irregular Networks

    Directory of Open Access Journals (Sweden)

    L. Keerthana

    2012-06-01

    Full Text Available A Strategy of Multispanning Tree Zone Ordered Label Based routing is improved with Efficient and Reliable (EAR routing for irregular networks is presented and analyzed in this work. Most existing deadlock free routing methods for irregular topologies impose several limitations on node and channel labeling in an irregular network is based on a pre-defined spanning tree.It is not possible to form a deadlock free zone of three or four channel labels for two spanning tree. So this existing Multispanning Tree Zone Ordered Label Based routing is modified with Efficient and Reliable (EAR routing. EAR is based on four parameters length of the path,distance traversed,transmission of link and energy levels to dynamically determine and maintain the best routes.. The simulation results have shown highest packet delivery ratio, minimum latency, and energy consumption.

  4. Energy Extraction from a Slider-Crank Wave Energy under Irregular Wave Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-08-24

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  5. Implied Evolutionary Differences of the Jovian Irregular Satellites from a BVR Color Survey

    Science.gov (United States)

    Rettig, Terrence W.; Walsh, Kevin; Consolmagno, Guy

    2001-12-01

    We present BVR colors and magnitudes for four jovian irregular prograde satellites (Himalia J6, Elara J7, Lysithea J10, and Leda J13) and four irregular retrograde satellites (Pasiphae J8, Sinope J9, Carme J11, and Ananke J12). All eight have generally 'solar' colors but the retrograde group has slightly redder and more diverse colors. The strikingly similar colors of the four prograde satellites suggest the parent planetesimal was likely very homogeneous. The four retrograde satellites show a diversity in color that suggests a heterogeneous progenitor and thus variations in precapture formation history. The absolute magnitudes and revised diameters are presented. We also report new colors and diameters for two uranian irregular satellites (Caliban (S/1997 U1) and Sycorax (S/1997 U2) that are slightly redder than any of these jovian satellites.

  6. Suction-based grasping tool for removal of regular- and irregular-shaped intraocular foreign bodies.

    Science.gov (United States)

    Erlanger, Michael S; Velez-Montoya, Raul; Mackenzie, Douglas; Olson, Jeffrey L

    2013-01-01

    To describe a suction-based grasping tool for the surgical removal of irregular-shaped and nonferromagnetic intraocular foreign bodies. A surgical tool with suction capabilities, consisting of a stainless steel shaft with a plastic handle and a customizable and interchangeable suction tip, was designed in order to better engage and manipulate irregular-shaped in-traocular foreign bodies of various sizes and physical properties. The maximal suction force and surgical capabilities were assessed in the laboratory and on a cadaveric eye vitrectomy model. The suction force of the water-tight seal between the intraocular foreign body and the suction tip was estimated to be approximately 40 MN. During an open-sky vitrectomy in a porcine model, the device was successful in engaging and firmly securing foreign bodies of different sizes and shapes. The suction-based grasping tool enables removal of irregular-shaped and nonferromagnetic foreign bodies. Copyright 2013, SLACK Incorporated.

  7. Detection of a Solitude Senior's Irregular States Based on Learning and Recognizing of Behavioral Patterns

    Science.gov (United States)

    Aoki, Shigeki; Onishi, Masaki; Kojima, Atsuhiro; Fukunaga, Kunio

    Recently, attention is paid to monitoring systems that watch behavior of a solitude person in home as the population of solitude seniors has increased. This paper proposes a monitoring system focused on behavioral patterns of a solitude senior. In general, the number of behavioral patterns are limited in the case of aged person in a room. It is possible for a system like a HMM to learn the frequently appeared behavioral patterns. By utilizing HMMs to deal with behavioral patterns, the system can detect irregular pattern by the degree of likelihood in the case when non-daily behavioral patterns appeared. Such a case could be an irregular state of the living life of the person. Soon after, the system reports an alarm of occurrence of the irregular state according to demand.

  8. Spinning Dust Emission: Effects of irregular grain shape, transient heating and comparison with WMAP results

    CERN Document Server

    Hoang, Thiem; Draine, B T

    2011-01-01

    Planck is expected to answer crucial questions on the early Universe, but it also provides further understanding on anomalous microwave emission. Electric dipole emission from spinning dust grains continues to be the favored interpretation of anomalous microwave emission. In this paper, we present a method to calculate the rotational emission from small grains of irregular shape with moments of inertia $I_{1}\\ge I_{2}\\ge I_{3}$. We show that a torque-free rotating irregular grain with a given angular momentum radiates at multiple frequency modes. The resulting spinning dust spectrum has peak frequency and emissivity increasing with the degree of grain shape irregularity, which is defined by $I_{1}:I_{2}:I_{3}$. We discuss how the orientation of dipole moment $\\bmu$ in body coordinates affects the spinning dust spectrum for different regimes of internal thermal fluctuations. We show that the spinning dust emissivity for the case of strong thermal fluctuations is less sensitive to the orientation of $\\bmu$ than...

  9. A new angle for probing field-aligned irregularities with the Murchison Widefield Array

    CERN Document Server

    Loi, Shyeh Tjing; Cairns, Iver H; Trott, Cathryn M; Hurley-Walker, Natasha; Feng, Lu; Hancock, Paul J; Kaplan, David L

    2016-01-01

    Electron density irregularities in the ionosphere are known to be magnetically anisotropic, preferentially elongated along the lines of force. While many studies of their morphology have been undertaken by topside sounding and whistler measurements, it is only recently that detailed regional-scale reconstructions have become possible, enabled by the advent of widefield radio telescopes. Here we present a new approach for visualising and studying field-aligned irregularities (FAIs), which involves transforming interferometric measurements of TEC gradients onto a magnetic shell tangent plane. This removes the perspective distortion associated with the oblique viewing angle of the irregularities from the ground, facilitating the decomposition of dynamics along and across magnetic field lines. We apply this transformation to the dataset of Loi et al. [2015a], obtained on 15 October 2013 by the Murchison Widefield Array (MWA) radio telescope and displaying prominent FAIs. We study these FAIs in the new reference f...

  10. Influence of Track Irregularity on Longitudinal Vibration of Wheelset and Correlation Performance

    Institute of Scientific and Technical Information of China (English)

    Ma Weihua; Luo Shihui; Song Rongrong

    2006-01-01

    Longitudinal vibration of wheelset with respect to bogie frame often exists with a high acceleration magnitude and relative high frequency. First, a simplified model with a single wheelset moving at a constant speed on a tangential track with irregularity is used to investigate the longitudinal vibration dynamics. Computational results indicate that the longitudinal vibration frequency of the wheelset is most sensitive to the primary longitudinal stiffness and the mass of the wheelset. As to the locomotive model, the longitudinal vibration is concerned with cross-level irregularity and vertical profile irregularity. Meanwhile, a method to estimate the resonance speed is presented. Finally, a possible solution is brought forward to extend wheel-rail service life by eliminating longitudinal vibration of the wheelset. The solution is simply to arrang the primary vertical damper with a forward angle, so that its damping component can be applied to longitudinal direction.

  11. Institutional Root Cause of the Irregularity of Social Security Funds in China

    Institute of Scientific and Technical Information of China (English)

    Bingwen Zheng

    2007-01-01

    This paper analyzes institutional defects in the Chinese social security system, based on irregularities in social security funds revealed in the Audit Report by the China National Audit Office. The author divides the irregularities into five categories according to the nature of fund use. The results show that the institutional root cause of the irregularities lies in the unreasonable design and operation of the social security system, which currently faces management and institutional risks. This paper argues that simple rhetoric about strengthening regulation and supervision cannot help to reduce illegal practices, or to realize risk control. The only solution is to reform the social security system. Specifically, the Chinese Government should regulate the administrative cost of the social security system,and the behavior of its agencies, through legislation, reform the investment regime to increase rate of return of pension assets, and adjust and reshape the existing social security system, so as to elevate its pooling level.

  12. Vulnerability, irregular migrants' health-related rights and the European Court of Human Rights.

    Science.gov (United States)

    Da Lomba, Sylvie

    2014-09-01

    The protection of irregular migrants' health-related rights brings to the fore the tensions that exist between human rights, citizenship and the sovereign state, and exposes the protection gaps in the international human rights regime. With this in mind, I consider the merits of a vulnerability analysis in international human rights law (IHRL). I posit that, detached from specific groups and reconceptualised as universal, vulnerability can be reclaimed as a foundation and tool of IHRL. I further contend that the deployment of a vulnerability analysis can alleviate the exclusionary dimension of IHRL and extend protections to irregular migrants. On this basis, I investigate the development of a vulnerability analysis in the case law of the European Court of Human Rights. I argue that, in contrast with the Court's vulnerable population approach, a vulnerability analysis can improve protection standards for irregular migrants in the field of health.

  13. A Novel Energy Yields Calculation Method for Irregular Wind Farm Layout

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen;

    2015-01-01

    Due to the increasing size of offshore wind farm, the impact of the wake effect on energy yields become more and more evident. The Seafloor topography would limit the layout of the wind farm so that irregular layout is usually adopted inlarge scale offshore wind farm. However, the calculation...... for the energy yields in irregular wind farm considering wake effect would be difficult.In this paper, a mathematical model which includes the impacts of the variation of both wind direction and velocityon wake effect is established. Based on the wake model, a binary matrix method is proposed for the energy...... yields calculation forirregular wind farms.The results show that the proposed wake model is effective in calculating the wind speeddeficit. The calculation framework is applicable for energy yields calculation in irregular wind farms....

  14. Spiking irregularity and frequency modulate the behavioral report of single-neuron stimulation.

    Science.gov (United States)

    Doron, Guy; von Heimendahl, Moritz; Schlattmann, Peter; Houweling, Arthur R; Brecht, Michael

    2014-02-01

    The action potential activity of single cortical neurons can evoke measurable sensory effects, but it is not known how spiking parameters and neuronal subtypes affect the evoked sensations. Here, we examined the effects of spike train irregularity, spike frequency, and spike number on the detectability of single-neuron stimulation in rat somatosensory cortex. For regular-spiking, putative excitatory neurons, detectability increased with spike train irregularity and decreasing spike frequencies but was not affected by spike number. Stimulation of single, fast-spiking, putative inhibitory neurons led to a larger sensory effect compared to regular-spiking neurons, and the effect size depended only on spike irregularity. An ideal-observer analysis suggests that, under our experimental conditions, rats were using integration windows of a few hundred milliseconds or more. Our data imply that the behaving animal is sensitive to single neurons' spikes and even to their temporal patterning.

  15. Irregular Wave Energy Extraction Analysis for a Slider Crank WEC Power Take-Off System

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard

    2015-09-02

    Slider crank Wave Energy Converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this WEC has been done under regular sinusoidal wave conditions, and a suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and the control methodology is modified to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but still a reasonable amount of energy can be extracted.

  16. Moduli of unramified irregular singular parabolic connections on a smooth projective curve

    CERN Document Server

    Inaba, Michi-aki

    2012-01-01

    In this paper we construct a coarse moduli scheme of stable unramified irregular singular parabolic connections on a smooth projective curve and prove that the constructed moduli space is smooth and has a symplectic structure. Moreover we will construct the moduli space of generalized monodromy data coming from topological monodromies, formal monodromies, links and Stokes data associated to the generic irregular connections. We will prove that for a generic choice of generalized local exponents, the generalized Riemann-Hilbert correspondence from the moduli space of the connections to the moduli space of the associated generalized monodromy data gives an analytic isomorphism. This shows that differential systems arising from (generalized) isomonodromic deformations of corresponding unramified irregular singular parabolic connections admit geometric Painlev\\'e property as in the regular singular cases proved generally in \\cite{Inaba-1}.

  17. Decoding Complexity of Irregular LDGM-LDPC Codes Over the BISOM Channels

    CERN Document Server

    Raina, Manik

    2010-01-01

    An irregular LDGM-LDPC code is studied as a sub-code of an LDPC code with some randomly \\emph{punctured} output-bits. It is shown that the LDGM-LDPC codes achieve rates arbitrarily close to the channel-capacity of the binary-input symmetric-output memoryless (BISOM) channel with bounded \\emph{complexity}. The measure of complexity is the average-degree (per information-bit) of the check-nodes for the factor-graph of the code. A lower-bound on the average degree of the check-nodes of the irregular LDGM-LDPC codes is obtained. The bound does not depend on the decoder used at the receiver. The stability condition for decoding the irregular LDGM-LDPC codes over the binary-erasure channel (BEC) under iterative-decoding with message-passing is described.

  18. Topography-Dependent Eikonal Traveltime Tomography for Upper Crustal Structure Beneath an Irregular Surface

    Science.gov (United States)

    Ma, Ting; Zhang, Zhongjie

    2015-06-01

    Seismic modeling of the crust with nonflat topography can be made by first-arrival traveltime tomography, which faces the challenge of an irregular free surface. A feasible way to deal with this problem consists of expanding the physical space by overlapping a low velocity layer above the irregular surface in order to have a flat topography, besides using the classical eikonal equation solver for traveltime computation. However, the undesirable consequences of this method include seismic ray deviations due to the transition from an irregular surface that is the free boundary to an inner discontinuity lying in the expanded computational space. An alternative solution, called irregular surface flattening, which involves the transformation between curvilinear and Cartesian coordinate systems, has been recently proposed through the formulation of the topography-dependent eikonal equation (TDEE) and a new solver for forward modeling of traveltimes. Based on the solution of this equation, we present topography-dependent eikonal traveltime tomography (hereafter TDETT) for seismic modeling of the upper crust. First-arrival traveltimes are calculated using the TDEE solver and the raypaths with the minimum traveltime that can be found by following the steepest traveltime gradient from the receiver to the source. By solving an algebraic equation system that connects the slowness perturbations with the already determined traveltimes, these variables can be obtained making use of the back-projection algorithm. This working scheme is evaluated through three numerical examples with different topographic complexities that are conducted from synthetic data and a fourth example with somewhat more complicated topography and real data acquired in northeastern Tibet. The comparison of the results obtained by both methods, i.e., physical space expansion above the irregular surface and irregular surface flattening, fully validates the tomography scheme that is proposed to construct

  19. Turbulent boundary layers under irregular waves and currents: Experiments and the equivalent-wave concept

    Science.gov (United States)

    Yuan, Jing

    2016-04-01

    A full-scale experimental study of turbulent boundary layer flows under irregular waves and currents is conducted with the primary objective to investigate the equivalent-wave concept by Madsen (1994). Irregular oscillatory flows following the bottom-velocity spectrum under realistic surface irregular waves are produced over two fixed rough bottoms in an oscillatory water tunnel, and flow velocities are measured using a Particle Image Velocimetry. The root-mean-square (RMS) value and representative phase lead of wave velocities have vertical variations very similar to those of the first-harmonic velocity of periodic wave boundary layers, e.g., the RMS wave velocity follows a logarithmic distribution controlled by the physical bottom roughness in the very near-bottom region. The RMS wave bottom shear stress and the associated representative phase lead can be accurately predicted using the equivalent-wave approach. The spectra of wave bottom shear stress and boundary layer velocity are found to be proportional to the spectrum of free-stream velocity. Currents in the presence of irregular waves exhibit the classic two-log-profile structure with the lower log-profile controlled by the physical bottom roughness and the upper log-profile controlled by a much larger apparent roughness. Replacing the irregular waves by their equivalent sinusoidal waves virtually makes no difference for the coexisting currents. These observations, together with the excellent agreement between measurements and model predictions, suggest that the equivalent-wave representation adequately characterizes the basic wave-current interaction under irregular waves.

  20. Characteristics of Scour and Deposition in Front of Breakwaters Under Irregular Broken Clapotis

    Institute of Scientific and Technical Information of China (English)

    高学平; 张亚; 李昌良

    2004-01-01

    First the scour and deposition patterns of the sandy seabed in front of a vertical breakwater under the action of irregular broken clapotis are investigated experimentally and classified into five types: scour type Ⅰ , scour type Ⅱ , scour typeⅢ, deposition type Ⅰ , and deposition type Ⅱ . Secondly, the processes of formation of scour and deposition patterns are probed in comparison with those induced by regular broken clapotis and standing waves. Thirdly, the criteria for distinguishing scour and deposition patterns under irregular broken clapotis are presented.

  1. Proceso de formación de asentamientos irregulares en Guadalajara

    OpenAIRE

    Ruiz-Velasco, Guadalupe; Solinís, Germán

    1988-01-01

    Se expone el proceso social desencadenado durante la formación de siete asentamientos irregulares en la zona metropolitana de Guadalajara: Lomas de Tabachines, Lomas de Oblatos, Hernández Loza, Lázaro Cárdenas, Mezquitera, Nueva España y Agrícola. Se expone la organización social y política que supone la formación de asentamientos irregulares, desde su comercialización ilegal hasta su inclusión en la estructura urbana formal, revisando también los aspectos concretos de la vivienda como expres...

  2. A Tire Model for Off-Highway Vehicle Simulation on Short Wave Irregular Terrain

    DEFF Research Database (Denmark)

    Langer, Thomas Heegaard; Kristensen, Lars B; Mouritsen, Ole Ø.

    2010-01-01

    Manufacturers of construction machinery are challenged in several ways concerning dynamic loads. Considering off-highway dump trucks that travel through high amplitude short wave irregular terrain with considerable speed two aspects concerning dynamics are important. The first is the legal...... the tire ground interaction for big off-road tires on short wave irregular terrain. In this paper a simple tire model combining the well known slip theory and a displaced volume approach is presented. A non-gradient optimization routine is applied for parameter identification by minimizing the difference...

  3. Experimental study on bed-load sediment transport under irregular wave and current combined flow

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using an irregularly oscillating tray and flume, a series of experiments are completed to evaluate bed-load sediment transport rate under irregular wave- current coexistent fild. Testing conditions include three interaction angles 0°, 45°, 90° and two kinds of median sizes (0.38 and 1.10 mm).The results of transport rate show that the net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress of waves, mean shear stress of current and the grain size.

  4. Attitude Analysis and Robust Adaptive Backstepping Sliding Mode Control of Spacecrafts Orbiting Irregular Asteroids

    Directory of Open Access Journals (Sweden)

    Chunhui Liang

    2014-01-01

    Full Text Available Attitude stability analysis and robust control algorithms for spacecrafts orbiting irregular asteroids are investigated in the presence of model uncertainties and external disturbances. Rigid spacecraft nonlinear attitude models are considered and detailed attitude stability analysis of spacecraft subjected to the gravity gradient torque in an irregular central gravity field is included in retrograde orbits and direct orbits using linearized system model. The robust adaptive backstepping sliding mode control laws are designed to make the attitude of the spacecrafts stabilized and responded accurately to the expectation in the presence of disturbances and parametric uncertainties. Numerical simulations are included to illustrate the spacecraft performance obtained using the proposed control laws.

  5. Discrete transfer method with the concept of blocked-off region for irregular geometries

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, Prabal [Institute of Fluid Mechanics (LSTM), University of Erlangen-Nuremberg, Cauerstrasse 4, D-91058 Erlangen (Germany)]. E-mail: prabal_iitg@yahoo.com

    2006-03-15

    The discrete transfer method (DTM) is applied to irregular geometries with a concept of blocked-off region previously applied in the problems of computational fluid dynamics. This gives a new alternative to the DTM for its implementation to irregular structures. The Cartesian coordinate-based ray-tracing algorithm can be applied to the geometries with inclined or curved boundaries. Some test problems are considered and results are validated with the available results in the literature. Both radiative and non-radiative equilibrium situations are considered. The medium is assumed to be both participating and non-participating. Results are found to be accurate for all kinds of situations.

  6. Effect of Body Acceleration on Pulsatile Flow of Micropolar Fluid through an Irregular Arterial Stenosis

    Science.gov (United States)

    Abdullah, Ilyani; Amin, Norsarahaida

    2008-01-01

    The present study deals with the effect of body acceleration together with surface irregularities on blood flow in artery. Prolonged exposure to high level unintended acceleration may cause serious health problems in the cardiovascular system. The situations like riding in vehicles, flying in airplanes and fast body movements during sport activities can lead to the impairment of certain physiological functions. A micropolar model of blood flow through an irregular arterial stenosis is considered. The governing equations involving unsteady nonlinear two-dimensional partial differential equations are solved employing finite difference scheme. Computational results on the velocity profiles and the flow characteristics are presented.

  7. Less Efficient Neural Processing Related to Irregular Sleep and Less Sustained Attention in Toddlers.

    Science.gov (United States)

    Hoyniak, Caroline P; Petersen, Isaac T; McQuillan, Maureen E; Staples, Angela D; Bates, John E

    2015-01-01

    The current study used event-related potentials to examine a candidate process through which sleep difficulties affect attentional processing in toddlers. Fifteen toddlers participated in an auditory Oddball task while neurophysiological data were collected. Sleep deficits were assessed using actigraphs, and attention was examined with a sustained attention task. A P3-like component was elicited from the toddlers, and longer target P3 latencies were associated with poorer sustained attention and irregular sleep. Findings suggest that irregular sleep is associated with less efficient attentional processing as reflected by the P3 component, and that longer target P3 latencies are associated with poorer sustained attention.

  8. Very weak solutions of wave equation for Landau Hamiltonian with irregular electromagnetic field

    Science.gov (United States)

    Ruzhansky, Michael; Tokmagambetov, Niyaz

    2017-04-01

    In this paper, we study the Cauchy problem for the Landau Hamiltonian wave equation, with time-dependent irregular (distributional) electromagnetic field and similarly irregular velocity. For such equations, we describe the notion of a `very weak solution' adapted to the type of solutions that exist for regular coefficients. The construction is based on considering Friedrichs-type mollifier of the coefficients and corresponding classical solutions, and their quantitative behaviour in the regularising parameter. We show that even for distributional coefficients, the Cauchy problem does have a very weak solution, and that this notion leads to classical or distributional-type solutions under conditions when such solutions also exist.

  9. DESIGN OF IRREGULAR LDPC CODE WITH UNEQUAL ERROR PROTECTION PROPERTY AND ITS PERFORMANCE ANALYSIS ON IMAGE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    Wang Ruihua; Yin Liuguo; Yu Quan; Lu Jianhua

    2005-01-01

    Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular LDPC codes with Unequal Error Protection (UEP)property is designed in this letter. Simulation results show that the transmission quality of the image may be effectively improved with this class of irregular LDPC code.

  10. Caring for the Unseen: Using Linking Social Capital to Improve Healthcare Access to Irregular Migrants in Spain

    OpenAIRE

    Mason, Deanna Marie

    2016-01-01

    Abstract Purpose To describe a novel strategy using linking social capital to provide healthcare access to irregular migrants with low literacy, low numeracy, and limited cultural assimilation in a European metropolitan area. Organizing Construct Public data show numerous shortcomings in meeting the healthcare needs of refugees and irregular migrants surging into Europe. Many irregular migrants living in European communities are unable to access information, care, or services due to lack of s...

  11. Wilson fermion doubling phenomenon on irregular lattice: the similarity and difference with the case of regular lattice

    CERN Document Server

    Vergeles, S N

    2015-01-01

    It is shown that the Wilson fermion doubling phenomenon on irregular lattices (simplicial complexes) does exist. This means that the irregular (not smooth) zero or soft modes exist. The statement is proved on 4 Dimensional lattice by means of the Atiyah-Singer index theorem, then it is extended easily into the cases $D<4$. But there is a fundamental difference between doubled quanta on regular and irregular lattices: in the latter case the propagator decreases exponentially. This means that the doubled quanta on irregular lattice are "bad" quasiparticles.

  12. Optimized Irregular Low-Density Parity-Check Codes for Multicarrier Modulations over Frequency-Selective Channels

    Directory of Open Access Journals (Sweden)

    Gelle Guillaume

    2004-01-01

    Full Text Available This paper deals with optimized channel coding for OFDM transmissions (COFDM over frequency-selective channels using irregular low-density parity-check (LDPC codes. Firstly, we introduce a new characterization of the LDPC code irregularity called “irregularity profile.” Then, using this parameterization, we derive a new criterion based on the minimization of the transmission bit error probability to design an irregular LDPC code suited to the frequency selectivity of the channel. The optimization of this criterion is done using the Gaussian approximation technique. Simulations illustrate the good performance of our approach for different transmission channels.

  13. EXPERIMENTAL STUDY ON BED-LOAD SEDIMENT TRANSPORT IN IRREGULAR WAVE-CURRENT COEXISTENT FIELD

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to evaluate bed-load sediment transport in an irregular wave-current coexistent field, a series of experiments were completed in laboratory with an irregularly oscillating tray, which was specially designed to simulate the irregular wave-current coexistent field. Experimental results are presented on the initial motion of sediment and the rates of transport over flat horizontal bed. Testing conditions included three interaction angles, 0°, 45°, 90° and six kinds of grain sizes. Four kinds (0.2mm, 0.46mm, 0.85mm and 1.3mm) were used for the tests of initial motion, while the other two kinds (0.38mm and 1.1mm) for the tests of transport rate. Comparisons between experimental results of initial motion and modified Shields curve indicate that the Shields curve is still valid for the case of irregular wave-current coexistent field. Analysis of flow regime shows that initial conditions fall within smooth-turbulent transitional region. The results of transport rate show us that net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress and mean shear stress. A dimensionless formula is proposed on the basis of mechanism "Waves erode sediments, tides transport sediments".

  14. Digital Elevation Map Reconstruction for Port-based Dynamic Simulation of Contacts on Irregular Surfaces

    NARCIS (Netherlands)

    Wassink, Martin; Carloni, Raffaella; Poulakis, Pantelis; Stramigioli, Stefano

    2009-01-01

    This paper presents a method to utilize a port-based multibody contact model for simulating dynamic interaction between irregular surfaces. The existing compliant contact model requires an analytic parametrization of the surfaces involved in the interaction, the definition of a Gauss frame in each o

  15. Urano y sus dos satélites irregulares recientemente descubiertos

    Science.gov (United States)

    Parisi, M. G.; Brunini, A.

    Hasta hace poco tiempo, Urano era el único de los Planetas Gigantes que no poseía satélites irregulares. Esto lo diferenciaba del resto de los planetas Gigantes, al igual que la peculiar oblicuidad de su eje de spin. La gran inclinación de su eje de rotación se debe probablemente a una colisión que sufrió el planeta con otro embrión planetario al final del proceso de formación. Esta colisión habría desligado satélites exteriores preexistentes del planeta. Recientemente se han descubierto dos satélites irregulares de Urano, lo que introduce algunas nuevas cotas y condiciones en el escenario de la "Hipótesis de la Gran Colisión" . Los satélites irregulares de Urano tuvieron que ser capturados en una etapa posterior a la del escenario de la Gran Colisión, de no ser así, hubieran sido eyectados del sistema por el impulso impartido con ese gran impacto. En este trabajo, se discuten los posibles mecanismos de captura de los satélites irregulares y se presenta un nuevo posible mecanismo para dicha captura.

  16. ABO/RH DISTRIBUTION PATTERN AND PREVALENCE OF IRREGULAR ANTIBODIES IN HEALTHY BLOOD DONORS OF UTTARAKHAND

    Directory of Open Access Journals (Sweden)

    Brijesh Thakur

    2016-07-01

    Full Text Available BACKGROUND Blood group plays a vital role in transfusion safety, understanding genetics, inheritance pattern and disease susceptibility. This study is aimed to determine distribution pattern of ABO and Rh blood group, incidence and identification of irregular antibodies among blood donors of Uttarakhand. METHOD ABO/Rh blood grouping was performed by test tube agglutination method (both cell and serum grouping using antisera A, B and Rh from Tulip and Orthodiagnostics. Donors’ plasma were screened for irregular antibodies by indirect antiglobulin technique using Bio-Rad ID-Card “LISS/Coombs” and test cell reagents “ID-DiaCell” via gel centrifugation. RESULTS Out of total 4573 included blood donors, 88.2% were males. The maximum blood donors (77.6% were in 18-25 years of age group. The commonest ABO blood group present was B (36.1% followed by O (29.1%, A (24.8% and AB (10% in blood donors; while in Rhesus system, 95.0% donors were Rh-positive and 5.0% donors were Rh negative. Screening of donors’ plasma did not reveal any detectable irregular antibody. CONCLUSION The study has a significant implication in suggesting the distribution pattern of ABO/Rh blood group typing in the region, but routine irregular antibody screening in healthy blood donors may not be fruitful in this region keeping cost effectiveness and absence of previous sensitization in mind

  17. A Novel Short-Range Prediction Model for Railway Track Irregularity

    Directory of Open Access Journals (Sweden)

    Peng Xu

    2012-01-01

    Full Text Available In recent years, with axle loads, train loads, transport volume, and travel speed constantly increasing and railway network steadily lengthening, shortcomings of current maintenance strategies are getting to be noticed from an economical and safety perspective. To overcome the shortcomings, permanent-of-way departments throughout the world have given a considerable attention to an ideal maintenance strategy which is to carry out appropriate maintenances just in time on track locations really requiring maintenance. This strategy is simplified as the condition-based maintenance (CBM which has attracted attentions of engineers of many industries in the recent 70 years. To implement CBM for track irregularity, there are many issues which need to be addressed. One of them focuses on predicting track irregularity of each day in a future short period. In this paper, based on track irregularity evolution characteristics, a Short-Range Prediction Model was developed to this aim and is abbreviated to TI-SRPM. Performance analysis results for TI-SRPM illustrate that track irregularity amplitude predictions on sampling points by TI-SRPM are very close to their measurements by Track Geometry Car.

  18. Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

    NARCIS (Netherlands)

    Janic, M.

    2009-01-01

    This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

  19. Parallel ocean flow computations on a regular and on an irregular grid

    NARCIS (Netherlands)

    Gijzen, M.B. van

    2001-01-01

    Ocean flow problems can be discretized and solved on a regular grid, by taking l and points into account in the computations, or on an irregular grid. In the latter approach, the number of unknowns is less than for the regular grid. The data structures are completely different for the two approaches

  20. VARIABLE-STARS IN THE IRREGULAR GALAXY NGC-2366 (DDO-42)

    NARCIS (Netherlands)

    TOLSTOY, E; SAHA, A; HOESSEL, JG; MCQUADE, K

    1995-01-01

    Observations of the resolved stars in the Irregular galaxy NGC 2366, obtained over the ten year period from March 1984 to March 1994, are presented. Thirty separate epochs were used to search for variable stars, and a total of 13 were found, of which 6 have characteristic Cepheid light curves and co

  1. Sinking of irregular shape blocks into marine seabed under wave-induced liquefaction

    DEFF Research Database (Denmark)

    Kirca, Özgür

    2013-01-01

    The sinking of initially buried irregular blocks into the seabed under wave-induced liquefaction was investigated by experimental methods. Pore-water pressure in the soil, water surface elevation time series and block displacements were measured. Results indicated that initiation of sinking...

  2. In situ irregularity identification and scintillation estimation using wavelets and CINDI on C/NOFS

    Science.gov (United States)

    Stoneback, R. A.; Heelis, R. A.; Caton, R. G.; Su, Y.-J.; Groves, K. M.

    2013-07-01

    Wavelets are a time-domain method that is able to extract both time and frequency information from a signal. The Morlet wavelet is used here to characterize the magnitude of ionospheric irregularities using measurements of the total ion density from the Coupled Ion Neutral Dynamics Investigation package onboard the Communications/Navigation Outage Forecasting System spacecraft. The power in ionospheric irregularities at scale sizes less than 128 km is used to generate an irregularity amplitude index. This index is used with a phase screen analysis to form an estimate of scintillation at the satellite location. The temporal information retained in a wavelet analysis also allows for an accurate power spectrum calculation even when used on short segments of data which is useful for real-time processing of irregularity detection onboard a satellite or for analyzing the long data sets produced by a satellite. To validate the process, a comparison of the in situ scintillation estimate and Scintillation Network and Decision Aid measurements of the S4 index is presented.

  3. Acquiring Regular and Irregular Past Tense Morphemes in English and French: Evidence from Bilingual Children

    Science.gov (United States)

    Nicoladis, Elena; Paradis, Johanne

    2012-01-01

    The aim of this study was to use crosslinguistic data from French-English bilinguals to test two models of past tense acquisition: (a) single route (all past tense forms rely on morphophonological schemas) and (b) dual route (irregular forms are learned as words, regulars through rules). These models make similar predictions about English…

  4. Gait Characteristics Associated with Trip-Induced Falls on Level and Sloped Irregular Surfaces

    Directory of Open Access Journals (Sweden)

    Andrew Merryweather

    2011-11-01

    Full Text Available Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped on smooth, hard surface (control and irregular (gravel, larger rocks surfaces. Walking on irregular surfaces significantly increased toe clearance compared to walking on the smooth surface. There was a significant (p < 0.05 decrease in cadence (steps/min, stride length (m, and speed (m/s from control to gravel to larger rocks. Significant changes in external rotation and increased knee flexion while walking on irregular surfaces were observed. Toe and heel clearance requirements increased on irregular surfaces, which may provide an explanation for trip-induced falls; however, the gait alterations observed in the experienced workers used as subjects would likely improve stability and recovery from a trip.

  5. Sharp mandibular bone irregularities after lower third molar extraction: Incidence, clinical features and risk factors

    Science.gov (United States)

    Alves-Pereira, Daniela; Valmaseda-Castellón, Eduard; Laskin, Daniel M.; Berini-Aytés, Leonardo; Gay-Escoda, Cosme

    2013-01-01

    Objectives: The purpose of this study was to determine the incidence and clinical symptoms associated with sharp mandibular bone irregularities (SMBI) after lower third molar extraction and to identify possible risk factors for this complication. Study Design: A mixed study design was used. A retrospective cohort study of 1432 lower third molar extractions was done to determine the incidence of SMBI and a retrospective case-control study was done to determine potential demographic and etiologic factors by comparing those patients with postoperative SMBI with controls. Results: Twelve SMBI were found (0.84%). Age was the most important risk factor for this complication. The operated side and the presence of an associated radiolucent image were also significantly related to the development of mandibular bone irregularities. The depth of impaction of the tooth might also be an important factor since erupted or nearly erupted third molars were more frequent in the SMBI group. Conclusions: SMBI are a rare postoperative complication after lower third molar removal. Older patients having left side lower third molars removed are more likely to develop this problem. The treatment should be the removal of the irregularity when the patient is symptomatic. Key words:Third molar, postoperative complication, bone irregularities, age. PMID:23524429

  6. Spelling Pronunciation and Visual Preview Both Facilitate Learning to Spell Irregular Words

    Science.gov (United States)

    Hilte, Maartje; Reitsma, Pieter

    2006-01-01

    Spelling pronunciations are hypothesized to be helpful in building up relatively stable phonologically underpinned orthographic representations, particularly for learning words with irregular phoneme-grapheme correspondences. In a four-week computer-based training, the efficacy of spelling pronunciations and previewing the spelling patterns on…

  7. Menstrual Irregularities and Related Plasma Hormone Levels in Multiple Sclerosis Patients Treated with Beta Interferone

    Directory of Open Access Journals (Sweden)

    Ehya Garshasbi

    2010-02-01

    Full Text Available Multiple sclerosis is a chronic inflammatory disease of central nervous system.Women are more susceptible to this disease. One of the obvious clinical complaints in women with multiple sclerosis specially treated with Beta Interferones is menstrual cycle irregularity. The aim of this study was to determine the prevalence of menstrual irregularities and probable changes in blood levels of related hormones (FSH, LH, PRL, TSH, T4, T3 in 58 females with definite MS treated with beta interferones versus 58 healthy women. In comparison to the control group, the patients had higher prevalence of irregular menstruation (P=0.001, oligomenorrhea (p=0.03, abnormal amount of menstrual blood flow (P=0.001, abnormal duration of menstrual flow (P=0.01 and missed period (P=0.04. Mean LH level in patients group was higher than control group (P=0.04.Hyperprolactinemia (>25.5ng/ml was more prevalent in patients group .There were not a significant difference in plasma levels of FSH and thyroid hormones between two groups. There were some relations between the type of Beta interferones and the subtype of menstrual irregularities in the patients. In conclusion, the results of this study emphasized the high rate of menstrual problem and changes of related plasma hormone levels in MS patients.

  8. Analysis of achievable capacity in irregularly-placed high performance mesh nodes

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-09-01

    Full Text Available challenge. This paper derives the achievable capacity limit of such HPNs’ placements. The analytical results show that the network capacity increases with the irregularity of HPNs placements, the number of antennas as well as the multiplicity of radios per...

  9. Large Scale Model Test Investigation on Wave Run-Up in Irregular Waves at Slender Piles

    DEFF Research Database (Denmark)

    Ramirez, Jorge Robert Rodriguez; Frigaard, Peter; Andersen, Thomas Lykke

    2013-01-01

    from high speed video recordings. Based on the measured run-up heights different types of prediction formulae for run-up in irregular waves were evaluated. In conclusion scale effects on run-up levels seems small except for differences in spray. However, run-up of individual waves is difficult...

  10. Health care for irregular migrants: pragmatism across Europe. A qualitative study.

    NARCIS (Netherlands)

    Dauvrin, M.; Lorant, V.; Sandhu, S.; Devillé, W.; Dia, H.; Dias, S.; Gaddini, A.; Ioannidis, E.; Jensen, N.K.; Kluge, U.; Mertaniemi, R.; Puigpinósi Riera, R.; Sarvary, A.; Straßmayr, C.; Stankunas, M.; Soares, J.J.F.; Welbel, M.; Priebe, S.

    2012-01-01

    Background: Health services in Europe face the challenge of delivering care to a heterogeneous group of irregular migrants (IM). There is little empirical evidence on how health professionals cope with this challenge. This study explores the experiences of health professionals providing care to IM i

  11. COMPARISON OF SCOURS IN FRONT OF VERTICAL BREAKWATERS DUE TO REGULAR AND IRREGULAR WAVES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper the scours of sand bed due to regular and irregular waves in front of vertical breakwaters, such as scouring patterns, scouring mechanisms, etc., are investigated. Thereby, the scours under the action of the two kinds of waves are compared connected.

  12. URANS simulations of ship motion responses in long-crest irregular waves

    Institute of Scientific and Technical Information of China (English)

    沈志荣; 叶海轩; 万德成

    2014-01-01

    In this paper, numerical prediction of ship motion responses in long-crest irregular waves by the URANS-VOF method is presented. A white noise spectrum is applied to generate the incoming waves to evaluate the motion responses. The procedure can replace a decade of simulations in regular wave with one single run to obtain a complete curve of linear motion response, conside-rably reducing computation time. A correction procedure is employed to adjust the wave generation signal based on the wave spe-ctrum and achieves fairly better results in the wave tank. Three ship models with five wave conditions are introduced to validate the method. The computations in this paper are completed by using the solver naoe-FOAM-SJTU, a solver developed for ship and ocean engineering based on the open source code OpenFOAM. The computational motion responses by the irregular wave procedure are compared with the results by regular wave, experiments and strip theory. Transfer functions by irregular wave closely agree with the data obtained in the regular waves, showing negligible difference. The comparison between computational results and experiments also show good agreements. The results better predicted by CFD method than strip theories indicate that this method can compensate for the inaccuracy of the strip theories. The results confirm that the irregular wave procedure is a promising method for the accurate prediction of motion responses with less accuracy loss and higher efficiency compared with the regular wave procedure.

  13. Molecular analyses of Pythium irregulare isolates from grapevines in South Africa suggest a single variable species

    Science.gov (United States)

    The Pythium irregulare species complex is the most common and widespread Pythium spp. associated with grapevines in South Africa. This species complex can be subdivided into several morphological and phylogenetic species that are all highly similar at the sequence level. The complex includes P. re...

  14. Time-accurate AB-simulations of irregular coastal waves above bathymetry

    NARCIS (Netherlands)

    Groesen, van E. (Brenny); Andonowati,; Lee, Joseph Hun-Wei; Ng, Chiu-On

    2011-01-01

    In this contribution the performance is shown of a hybrid spectral-spatial implementation of the AB model for uni-directional waves above varying bottom. For irregular waves of JONSWAP-type, with peak periods of 9 and 12[s], significant wave height of 3[m], running from 30 to 15[m] depth over a 1:20

  15. Menstrual irregularity and bone mass in premenopausal women: Cross-sectional associations with testosterone and SHBG

    Directory of Open Access Journals (Sweden)

    Otahal Petr

    2010-12-01

    Full Text Available Abstract Background There have been few studies examining the associations between menstrual irregularity, androgens and bone mass in population-based samples of premenopausal women. This study aimed to describe the associations between menstrual pattern, testosterone, sex hormone binding globulin (SHBG and bone mass in a population-based sample of premenopausal women. Methods Cross-sectional study (N = 382, mean age 31.5 years. Menstrual pattern was assessed by questionnaire, bone mass measured by quantitative ultrasound (QUS and androgen status was assessed by levels of serum testosterone, SHBG and the free androgen index (FAI. Results Women with irregular cycles (n = 41, 11% had higher free androgen index (FAI, P = 0.01 and higher QUS measurements including speed of sound (SOS, 1%, P Conclusion Irregular menstrual cycles were associated with higher bone mass in this population-based sample of premenopausal women suggesting menstrual disturbance should continue to be evaluated but may be less harmful for bone mass. The association between menstrual irregularity and bone mass was partially mediated by markers of androgen status especially free testosterone.

  16. Small irregular pulmonary nodules in low-dose CT : observer detection sensitivity and volumetry accuracy

    NARCIS (Netherlands)

    Xie, Xueqian; Willemink, Martin J.; de Jong, Pim A.; van Ooijen, Peter M. A.; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Greuter, Marcel J. W.

    2014-01-01

    OBJECTIVE: The purpose of this study is to evaluate observer detection and volume measurement of small irregular solid artificial pulmonary nodules on 64-MDCT in an anthropomorphic thoracic phantom. MATERIALS AND METHODS: Forty in-house-made solid pulmonary nodules (lobulated and spiculated; actual

  17. What Comes Next? An Argument for Irregular War in National Defense

    Science.gov (United States)

    2012-10-01

    conduct a static line jump from a C-130 aircraft during Fuerzas Comando 2012 at the Colom- bian National Training Center on Fort Tolemaida...combat operations in dollars and in human capital require an alternative. What comes next? The answer: An energized, muscular strategy of irregular war

  18. ON THE BOREL SUMMABILITY OF FORMAL SOLUTIONS FOR SOME FIRST ORDER SINGULAR PDES WITH IRREGULAR SINGULARITY

    Institute of Scientific and Technical Information of China (English)

    Chen Hua; Zhang Zhixiong

    2005-01-01

    In this paper the authors consider the summability of formal solutions for some first order singular PDEs with irregular singularity. They prove that in this case the formal solutions will be divergent, but except a enumerable directions, the formal solutions are Borel summable.

  19. Simultaneous radar and spaced receiver VHF scintillation observations of ESF irregularities

    Directory of Open Access Journals (Sweden)

    D. Tiwari

    2006-07-01

    Full Text Available Simultaneous observations of equatorial spread F (ESF irregularities made on 10 nights during March-April 1998 and 1999, using an 18-MHz radar at Trivandrum (77° E, 8.5° N, dip 0.5° N and two spaced receivers recording scintillations on a 251-MHz signal at Tirunelveli (77.8° E, 8.7° N, dip 0.4° N, have been used to study the evolution of Equatorial Spread F (ESF irregularities. Case studies have been carried out on the day-to-day variability in ESF structure and dynamics, as observed by 18-MHz radar, and with spaced receiver measurements of average zonal drift Vo of the 251-MHz radio wave diffraction pattern on the ground, random velocity Vc, which is a measure of random changes in the characteristics of scintillation-producing irregularities, and maximum cross-correlation CI of the spaced receivers signals. Results show that in the initial phase of plasma bubble development, the greater the maximum height of ESF irregularities responsible for the radar backscatter, the greater the decorrelation is of the spaced receiver scintillation signals, indicating greater turbulence. The relationship of the maximum spectral width derived from the radar observations and CI also supports this result.

  20. Integration and Interoperability of Special Operations Forces and Conventional Forces in Irregular Warfare

    Science.gov (United States)

    2009-06-12

    narco -trafficking, illicit arms dealing, illegal financial transactions); and law enforcement activities focusing on countering irregular...accustomed to working in scenarios and in situations that are very unstructured…Our people will generally come up with a very novel approach of how to solve

  1. Frustum-Traced Irregular Z-Buffers: Fast, Sub-pixel Accurate Hard Shadows.

    Science.gov (United States)

    Wyman, Chris; Hoetzlein, Rama; Lefohn, Aaron

    2016-05-25

    We further describe and analyze a real-time system for rendering antialiased hard shadows using irregular z-buffers (IZBs) that we first presented in Wyman et al. [1]. We focus on identifying bottlenecks, exploring these from an algorithmic complexity standpoint, and presenting techniques to improve performance. Our system remains interactive on a variety of game assets and CAD models while running at resolutions 1920 1080 and above and imposes no constraints on light, camera or geometry, allowing fully dynamic scenes without precomputation. We render sub-pixel accurate, 32 sample per pixel hard shadows at roughly twice the cost of a single sample per pixel. This allows us to smoothly animate even subpixel shadows from grass or wires without introducing spatial or temporal aliasing. Prior algorithms for irregular z-buffer shadows rely heavily on the GPU's compute pipeline. Instead we leverage the standard rasterization-based graphics pipeline, including hardware conservative raster and early-z culling. Our key observation is noting a duality between irregular z-buffer performance and shadow map quality; irregular z-buffering is most costly exactly where shadow maps exhibit the worst aliasing. This allows us to use common shadow map algorithms, which typically improve aliasing, to instead reduce our cost. Compared to state of the art ray tracers, we spawn similar numbers of triangle intersections per pixel yet completely rebuild our data structure in under 1 ms per frame.

  2. Irregular migration and informal economy in Southern and Central-Eastern Europe: breaking the vicious cycle?

    Science.gov (United States)

    Maroukis, Thanos; Iglicka, Krystyna; Gmaj, Katarzyna

    2011-01-01

    The flexible and cheap labour that European “post-industrial” economies are in need of is often facilitated by undeclared labour. The undocumented migrant, from his/her part, relatively easily finds work that suits his -- at least initial -- plans. What lies behind this nexus between irregular migration and informal economy? To what extent can this nexus be attributed to the structural features of the so-called “secondary”, as opposed to “primary”, labour market? And how does migration policy correlate with this economic context and lead to the entrapment of migrants in irregularity? Finally, can this vicious cycle of interests and life-strategies be broken and what does the experience of the migrants indicate in this respect? This paper addresses these questions via an exploration of the grounds upon which irregular migration and the shadow economy complement each other in southern Europe (SE) and central and Eastern Europe (CEE) (two regions at different points in the migration cycle). In doing so, the dynamic character of the nexus between informal economy and irregular migration will come to the fore, and the abstract identity of the “average” undocumented migrant will be deconstructed.

  3. Scintillation and irregularities from the nightside part of a Sun-aligned polar cap arc

    CERN Document Server

    van der Meeren, Christer; Lorentzen, Dag A; Paxton, Larry J; Clausen, Lasse B N

    2016-01-01

    In this paper we study the presence of irregularities and scintillation in relation to the nightside part of a long-lived, Sun-aligned transpolar arc on 15 January 2015. The arc was observed in DMSP UV and particle data and lasted at least 3 h between 1700 and 2000 UT. The arc was more intense than the main oval during this time. From all-sky imagers on Svalbard we were able to study the evolution of the arc, which drifted slowly westward toward the dusk cell. The intensity of the arc as observed from ground was 10-17 kR in 557.7 nm and 2-3.5 kR in 630.0 nm, i.e., significant emissions in both green and red emission lines. We have used high-resolution raw data from global navigation satellite systems (GNSS) receivers and backscatter from Super Dual Auroral Radar Network (SuperDARN) radars to study irregularities and scintillation in relation to the polar cap arc. Even though the literature has suggested that polar cap arcs are potential sources for irregularities, our results indicate only very weak irregular...

  4. Practical Aspects of the Spectral Analysis of Irregularly Sampled Data With Time-Series Models

    NARCIS (Netherlands)

    Broersen, P.M.T.

    2009-01-01

    Several algorithms for the spectral analysis of irregularly sampled random processes can estimate the spectral density for a low frequency range. A new time-series method extended that frequency range with a factor of thousand or more. The new algorithm has two requirements to give useful results. F

  5. The association between irregular menstruations and acne with asthma and atopy phenotypes.

    Science.gov (United States)

    Galobardes, Bruna; Patel, Sumaiya; Henderson, John; Jeffreys, Mona; Smith, George Davey

    2012-10-15

    Earlier menarche and irregular periods, among other markers of sex-hormone levels, have been associated with a higher risk of asthma and allergic diseases. This has suggested an etiologic role of sex hormones in the development of these conditions. The authors investigated the association of age at menarche, irregular periods, duration of menstruation, and acne with reported medical history of asthma and/or atopy (hay fever and/or eczema/urticaria) in a historical cohort of students born before the rise in asthma prevalence in the United Kingdom and attending university in 1948-1968. Finding consistent associations in a cohort that has experienced different life-course exposures and has different confounding structure can help to identify causal associations. In the Glasgow Alumni Cohort, irregular periods were associated with atopic asthma (multinomial odds ratio (MOR) = 2.79, 95% confidence interval (CI): 1.33, 5.83) and atopy alone (MOR = 1.40, 95% CI: 1.06, 1.84) but not with nonatopic asthma (MOR = 1.02, 95% CI: 0.45, 2.30), compared with students reporting no asthma and no atopy. The authors found no association with acne, a marker of high testosterone levels, that they hypothesized could point to polycystic ovary syndrome underpinning these associations. In summary, the authors found evidence for a potentially etiologic role of irregular menstruations with some specific asthma phenotypes, namely, atopic asthma and atopy, but not with nonatopic asthma.

  6. Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

    NARCIS (Netherlands)

    Janic, M.

    2009-01-01

    This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

  7. On initial enhancement of mesospheric dust associated plasma irregularities subsequent to radiowave heating

    Directory of Open Access Journals (Sweden)

    W. A. Scales

    2008-08-01

    Full Text Available Important observational manifestations of subvisible mesospheric dust are Polar Mesospheric Summer Echoes PMSE which are produced by scattering from electron irregularities produced by dust charging. It has been observed that the PMSE strength can be artificially modified by using a ground-based ionospheric heating facility to perturb the electron irregularity source region that is believed to produce PMSE. Recently it has become evident that significant diagnostic information may be available about the dust layer from the temporal behavior of the electron irregularities during the heating process which modifies the background electron temperature. Particularly interesting and important periods of the temporal behavior are during the turn-on and turn-off of the radiowave heating. Although a number of past theoretical and experimental investigations have considered the turn-off period, the objective here is to consider futher possibilities for diagnostic information available as well as the underlying physical processes. Approximate analytical models are developed and compared to a more accurate full computational model as a reference. Then from the temporal behavior of the electron irregularities during the turn-off of the radiowave heating, the analytical models are used to obtain possible diagnostic information for various charged dust and background plasma quantities.

  8. Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Marqueze

    2013-06-01

    Full Text Available OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively. The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05. Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively than moderately-active day-shift workers (116 and 73.3 mmHg, respectively (p < 0.05 as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively (p = 0.01. Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05. CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical

  9. HF-induced airglow structure as a proxy for ionospheric irregularity detection

    Science.gov (United States)

    Kendall, E. A.

    2013-12-01

    The High Frequency Active Auroral Research Program (HAARP) heating facility allows scientists to test current theories of plasma physics to gain a better understanding of the underlying mechanisms at work in the lower ionosphere. One powerful technique for diagnosing radio frequency interactions in the ionosphere is to use ground-based optical instrumentation. High-frequency (HF), heater-induced artificial airglow observations can be used to diagnose electron energies and distributions in the heated region, illuminate natural and/or artificially induced ionospheric irregularities, determine ExB plasma drifts, and measure quenching rates by neutral species. Artificial airglow is caused by HF-accelerated electrons colliding with various atmospheric constituents, which in turn emit a photon. The most common emissions are 630.0 nm O(1D), 557.7 nm O(1S), and 427.8 nm N2+(1NG). Because more photons will be emitted in regions of higher electron energization, it may be possible to use airglow imaging to map artificial field-aligned irregularities at a particular altitude range in the ionosphere. Since fairly wide field-of-view imagers are typically deployed in airglow campaigns, it is not well-known what meter-scale features exist in the artificial airglow emissions. Rocket data show that heater-induced electron density variations, or irregularities, consist of bundles of ~10-m-wide magnetic field-aligned filaments with a mean depletion depth of 6% [Kelley et al., 1995]. These bundles themselves constitute small-scale structures with widths of 1.5 to 6 km. Telescopic imaging provides high resolution spatial coverage of ionospheric irregularities and goes hand in hand with other observing techniques such as GPS scintillation, radar, and ionosonde. Since airglow observations can presumably image ionospheric irregularities (electron density variations), they can be used to determine the spatial scale variation, the fill factor, and the lifetime characteristics of

  10. Trends of ionospheric irregularities over African low latitude region during quiet geomagnetic conditions

    Science.gov (United States)

    Mungufeni, Patrick; Habarulema, John Bosco; Jurua, Edward

    2016-02-01

    The occurrence patterns of ionospheric irregularities during quiet geomagnetic conditions over the African low latitude region were analysed. GNSS-derived Total Electron Content of the ionosphere data during the period 2001-2012 were used. The data were obtained from Libreville, Gabon (0.35°N, 9.68°E, geographic, 8.05°S, magnetic), Mbarara, Uganda (0.60°S, 30.74°E, geographic, 10.22°S, magnetic), and Malindi, Kenya (2.99°S, 40.19°E, geographic, 12.42°S, magnetic). The rate of change of total electron content index greater than 0.5 TECU/Min were considered as severe ionospheric irregularities. For most of the time, the strength of ionospheric irregularities in March equinox were greater than those during September equinox over East Africa and an opposite observation was made over West Africa. These asymmetries might be due to the direction of the meridional winds during equinoxes over the different stations. Severity of ionospheric irregularity reduced from west towards the east. This might have been related to the decreasing geomagnetic field strength from east towards the west. This is the first study that reveals the equinoctial asymmetry is different in the West and East African sectors. Moreover, the importance of this study lies in the fact that it has used extensive data to examine the isolated and un-explained earlier observations of equinoctial asymmetry and longitudinal variation of ionospheric irregularities over the African low latitude region.

  11. Runtime buffer management to improve the performance in irregular Network-on-Chip architecture

    Indian Academy of Sciences (India)

    Umamaheswari S; Meganathan D; Raja Paul Perinbam J

    2015-06-01

    This paper presents a heterogeneous adaptable router to reduce latency in irregular mesh Network-on-Chip (NoC) architectures. Regular mesh-based NoC architecture may become irregular due to variable sized IPs and needs new routing algorithms to ensure throughput. Therefore, an irregular NoC mesh is considered and an adaptive algorithm is used for routing. The performance measures such as through-put, latency, and bandwidth are defined at design time to guarantee the performance of NoC. However, if the application has to change its communication pattern, parameters set at design time (say buffer size) may result in large area and power consumption or increased latency. Routers with large input buffers improve the efficiency of NoC communication, but they incur excessive power dissipation and hardware overheads. Routers with small buffers reduce power consumption, but result in high latency. In the proposed NoC router, input buffers can be dynamically allocated, thereby, latency can be reduced. In a 4 × 4 irregular mesh NoC with a buffer depth of 4 slots, 20% reduction in latency and 9% increase in throughput are attained using dynamic buffer allocation. An 8 × 8 irregular mesh NoC with the proposed router is exposed to the synthetic traffics like uniform, bit complement, tornado and hotspot traffics and it offered a 30.42% reduction in overall average latency and 18.33% increase in overall saturation throughput. The proposed router outperformed the static router by 22.63% less average latency for E3S benchmark applications. For the same performance, maximum of 55% reduction in buffer requirement and 53% less power consumption is achieved.

  12. Structuring of intermediate scale equatorial spread F irregularities during intense geomagnetic storm of solar cycle 24

    Science.gov (United States)

    Kakad, B.; Gurram, P.; Tripura Sundari, P. N. B.; Bhattacharyya, A.

    2016-07-01

    Here we examine the structuring of equatorial plasma bubble (EPB) during intense geomagnetic storm of solar cycle (SC) 24 that occurred on 17 March 2015 using spaced receiver scintillation observations on a 251 MHz radio signal, recorded by a network of stations in Indian region. As yet, this is the strongest geomagnetic storm (Dstmin˜-223nT) that occurred in present SC. Present study reveals that the structuring of equatorial spread F (ESF) irregularities was significantly different on 17 March as compared to quiet days of corresponding month. ESF irregularities of intermediate scale (100 m to few kilometers) are observed at unusually higher altitudes (≥ 800 km) covering wider longitudinal-latitudinal belt over Indian region. A presence of large-scale irregularity structures with stronger ΔN at raised F peak with small-scale irregularities at even higher altitudes is observed. It caused strong focusing effect (S4>1) that prevails throughout premidnight hours at dip equatorial station Tirunelveli. Other observational aspect is that zonal irregularity drifts over low-latitude station Kolhapur exhibited a large deviation of ˜230 m/s from their average quiet time pattern. During this geomagnetic storm, two southward turnings of significant strength (BZ≤-15 nT) occurred at 11.4 IST (Indian standard time) and 17.9 IST. The later southward turning of interplanetary magnetic field (IMF)BZ resulted in a large eastward prompt penetration electric field (PPEF) close to sunset hours in Indian longitude. Estimates of PPEF obtained from real-time ionospheric model are too low to explain the observed large upliftment of F region in the post sunset hours. Possible reason for observed enhanced PPEF-linked effects is discussed.

  13. A study on the status of and factors in irregular menstruation in university students

    Directory of Open Access Journals (Sweden)

    Tuba Ucar

    2015-06-01

    Methods: The present descriptive study was conducted at Health College of Inonu University between November 15 and December 01, 2012. The population was comprised of a total of 678 female students who studied Midwifery (n=212 and Nursing (n=466. No specific sample was chosen; therefore, all the participants were included within the scope of the study. However, the sample was comprised of a total of 365 students who volunteered to participate in the study. The data were obtained through the and ldquo;Personal Information Form and rdquo; and analyzed via such statistics as Pearson's Chi-Squared test, Fisher's exact test and t-test for independent groups. Results: The mean age of the participants was 20.28+/-1.99. While 46% of them studied midwifery, the remaining 54% studied nursing. The mean menarche age was 13.45+/-1.55 whereas the mean menstruation length was 5.61+/-1.88. The prevalence of irregular menstruation in the students was 23.8%. The study could not yield a correlation between irregular menstruation and age, presence of chronic disease and average daily sleep time with irregular menstruation (p>0.05. Those students who do not exercise regularly, had psychiatric disorders, regular drug users, in users of oral contraceptives, smoked and had higher Body-Mass Indices were more likely to suffer from irregular menstruation (p<0.05. Conclusions: The study concluded that nearly one-fourth of the students had irregular menstruation. The finding is promising inthat all these risk factors (obesity, smoking, sedentary living, medication and oral contraceptive use are avoidablewith changes in behaviors, for which healthcare professionals are significantly responsible [TAF Prev Med Bull 2015; 14(3.000: 215-221

  14. The first time observations of low-latitude ionospheric irregularities by VHF radar in Hainan

    Institute of Scientific and Technical Information of China (English)

    NING BaiQi; HU LianHuan; LI GuoZhu; LIU LiBo; WAN WeiXing

    2012-01-01

    Sanya VHF radar (18.4°N,109.6°E,dip latitude 12.8°N) at Hainan Island is the first coherent backscatter radar for sounding low-latitude ionospheric irregularities in the mainland of China.In this paper,we present the first results of low-latitude ionospheric E and F region irregularities using the radar data during the period from February 2009 to March 2010.The Doppler velocity of radar echoes from E region field aligned irregularities (FAIs) was about several tens of meters per second,while the Doppler spectral width was appreciably larger than the velocity,and could reach one hundred meters per second,indicating that the observed E region FAIs belonged to type 2 irregularities.The observations of range time intensity (RTI) maps of FAIs showed that E region irregularities most often occurred at night within the altitude range 85-115 km,and were rarely observed at afternoon hours.The percentage occurrence of E region FAIs maximized during spring months (Feb.-May) with a peak value over 80%.The heights at which the strongest echo related FAIs occurred were mainly around 100 km,lower than h'Es and the difference is mostly 10-20 km.December solstice seemed to be the minimum period of occurrence when the FAI echoes were commonly detected at a narrow altitude range 90-100 km.Moreover,simultaneous radar and GPS observations during spread F events in the pre-midnight hours of solar minimum revealed that significant GPS L band scintillations coincided with the appearance of F region plasma plume structures,which extended up to 450 km in altitude.

  15. Bayesian modeling of the covariance structure for irregular longitudinal data using the partial autocorrelation function.

    Science.gov (United States)

    Su, Li; Daniels, Michael J

    2015-05-30

    In long-term follow-up studies, irregular longitudinal data are observed when individuals are assessed repeatedly over time but at uncommon and irregularly spaced time points. Modeling the covariance structure for this type of data is challenging, as it requires specification of a covariance function that is positive definite. Moreover, in certain settings, careful modeling of the covariance structure for irregular longitudinal data can be crucial in order to ensure no bias arises in the mean structure. Two common settings where this occurs are studies with 'outcome-dependent follow-up' and studies with 'ignorable missing data'. 'Outcome-dependent follow-up' occurs when individuals with a history of poor health outcomes had more follow-up measurements, and the intervals between the repeated measurements were shorter. When the follow-up time process only depends on previous outcomes, likelihood-based methods can still provide consistent estimates of the regression parameters, given that both the mean and covariance structures of the irregular longitudinal data are correctly specified and no model for the follow-up time process is required. For 'ignorable missing data', the missing data mechanism does not need to be specified, but valid likelihood-based inference requires correct specification of the covariance structure. In both cases, flexible modeling approaches for the covariance structure are essential. In this paper, we develop a flexible approach to modeling the covariance structure for irregular continuous longitudinal data using the partial autocorrelation function and the variance function. In particular, we propose semiparametric non-stationary partial autocorrelation function models, which do not suffer from complex positive definiteness restrictions like the autocorrelation function. We describe a Bayesian approach, discuss computational issues, and apply the proposed methods to CD4 count data from a pediatric AIDS clinical trial. © 2015 The Authors

  16. Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

    Indian Academy of Sciences (India)

    Abhishek Kumar Singh; Amrita Das; Zeenat Parween; Amares Chattopadhyay

    2015-10-01

    The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

  17. Associations between structural characteristics of the school setting and irregular lunch consumption – are there gender differences?

    DEFF Research Database (Denmark)

    Pagh Pedersen, Trine; Holstein, Bjørn Evald; Krølner, Rikke

    regression, adjusting for individual level socio-demographic factors. Results: Having access to canteen/school stall was associated with a higher risk of irregular lunch consumption, OR=1.26 (1.04-1.52). No adult present in lunch breaks was associated with a higher risk of irregular lunch consumption, OR=1...

  18. Investigation of low-latitude ionospheric irregularities and their relationship to equatorial plasma bubbles using Sanya VHF radar

    Science.gov (United States)

    Ning, B.; Li, G.; Hu, L.

    2011-12-01

    A VHF radar has been set up at Sanya (18.34° N, 109.62° E, geomagnetic latitude 7.04°N), China in 2009. On the basis of the E, valley and F region irregularity observations detected by the Sanya VHF radar during equinoctial months, we focus on the simultaneous observations of E region irregularities disruption and valley region irregularities generation during the presence of post-sunset F region bubble structures. We stress that both the low latitude the E region irregularities (ERI) disruption and valley region irregularities (VRI) generation are associated with the development of post-sunset equatorial plasma bubble (EPB) structures. It is suggested that the electric field coupling from the unstable equatorial F region to low-latitude E and valley region could trigger and inhibit the occurrence of irregularities, depending on the polarity of the polarization electric field associated with the bifurcation of equatorial plasma bubbles. The mapping of upward/eastward and downward/eastward electric field associated with the west-tilted and east-tilted bubble structures, may be responsible for the disruption of E region irregularities, and the generation of valley region irregularities, respectively. However, more observations from multi instruments will be required to confirm such a scenario that the multi bifurcated EPBs play crucial roles for the simultaneous occurrence of low latitude ERI disruption and VRI generation.

  19. Processing of Regular and Irregular Past-Tense Verb Forms in First and Second Language Reading Acquisition

    NARCIS (Netherlands)

    Zeeuw, E.M. de; Schreuder, R.; Verhoeven, L.T.W.

    2013-01-01

    We investigated written word identification of regular and irregular past-tense verb forms by first (L1) and second language (L2) learners of Dutch in third and sixth grade. Using a lexical decision task, we measured speed and accuracy in the identification of regular and irregular past-tense verb

  20. Towards an Understanding of How Children Read and Spell Irregular Words: The Role of Nonword and Orthographic Processing Skills

    Science.gov (United States)

    Johnston, Rhona; McGeown, Sarah; Moxon, Gerri Elizabeth

    2014-01-01

    This study examined, in 180 children aged from 6 to 9?years, to what extent irregular word reading and spelling were predicted by vocabulary knowledge, reading frequency, orthographic processing and nonword reading skill. Consistent with models of reading highlighting the quasi-regular nature of irregular words, it was found that nonword reading…

  1. Monolingual and Bilingual Recognition of Regular and Irregular English Verbs: Sensitivity to Form Similarity Varies with First Language Experience.

    Science.gov (United States)

    Basnight-Brown, Dana M; Chen, Lang; Hua, Shu; Kostić, Aleksandar; Feldman, Laurie Beth

    2007-07-01

    We used a cross-modal priming procedure to explore the processing of irregular and regular English verb forms in both monolinguals and bilinguals (Serbian-English, Chinese-English). Materials included irregular nested stem (drawn-DRAW), irregular change stem (ran-RUN), and regular past tense-present tense verb pairs that were either low (guided-GUIDE) or high (pushed-PUSH) in resonance, a measure of semantic richness. Overall, semantic richness of irregular verbs (nested and irregular change) and of regular verbs (high and low resonance) was matched. Native speakers of English revealed comparable facilitation across regularity and greater facilitation for nested than change stem irregulars. Like native speakers, Serbian, but not Chinese bilinguals matched for proficiency, showed facilitation due to form overlap between irregular past and present tense forms with a nested stem. Unlike native speakers, neither group showed reliable facilitation to stem change irregulars. Results demonstrate the influence of first language on inflectional processing in a second language.

  2. Processing of Regular and Irregular Past-Tense Verb Forms in First and Second Language Reading Acquisition

    NARCIS (Netherlands)

    Zeeuw, E.M. de; Schreuder, R.; Verhoeven, L.T.W.

    2013-01-01

    We investigated written word identification of regular and irregular past-tense verb forms by first (L1) and second language (L2) learners of Dutch in third and sixth grade. Using a lexical decision task, we measured speed and accuracy in the identification of regular and irregular past-tense verb f

  3. Processing of Regular and Irregular Past-Tense Verb Forms in First and Second Language Reading Acquisition

    Science.gov (United States)

    de Zeeuw, Marlies; Schreuder, Rob; Verhoeven, Ludo

    2013-01-01

    We investigated written word identification of regular and irregular past-tense verb forms by first (L1) and second language (L2) learners of Dutch in third and sixth grade. Using a lexical decision task, we measured speed and accuracy in the identification of regular and irregular past-tense verb forms by children from Turkish-speaking homes (L2…

  4. The nature of the extended H I gas around NGC 4449 : The Dr. Jekyll Mr. Hyde of irregular galaxies

    NARCIS (Netherlands)

    Hunter, DA; Wilcots, EM; van Woerden, H; Gallagher, JS; Kohle, S

    1998-01-01

    We present interferometric H I 21 cm line observations of the extended gas around the irregular galaxy NGC 4449 covering 67' on the sky at a resolution of similar to 1'. The main star-forming body of NGC 4449 is relatively normal for a Magellanic irregular galaxy, but the galaxy is unusual in that

  5. Exploring Individual Differences in Irregular Word Recognition among Children with Early-Emerging and Late-Emerging Word Reading Difficulty

    Science.gov (United States)

    Steacy, Laura M.; Kearns, Devin M.; Gilbert, Jennifer K.; Compton, Donald L.; Cho, Eunsoo; Lindstrom, Esther R.; Collins, Alyson A.

    2017-01-01

    Models of irregular word reading that take into account both child- and word-level predictors have not been evaluated in typically developing children and children with reading difficulty (RD). The purpose of the present study was to model individual differences in irregular word reading ability among 5th grade children (N = 170), oversampled for…

  6. Do morphophonological rules impact both regular and irregular verb inflection? Evidence from acquired morphological impairment

    Directory of Open Access Journals (Sweden)

    Stacey Rimikis

    2015-05-01

    Full Text Available Introduction The role of morphophonological rules in production is a frequent point of contention in competing theories of morphological processing. Dual-mechanism theories have posited that a single default rule (stem+ed is used to produce the regular past tense, while all other past-tense forms are memorized and retrieved whole. However, research has suggested that a series of stochastic morphophonological rules plays a role in morphological productivity for both regular and irregular novel verbs (e.g. Albright & Hayes, 2003. Under this view, the likelihood of a given rule applying to a verb is partially dependent on its lexical support, measured as the number of phonologically similar verbs in the lexicon which take the same inflectional change (e.g. weep→wept, sweep→swept, etc.. To date, most evidence supporting this view has come from the morphological productivity of novel forms (e.g. Albright & Hayes, 2003 and from visual word recognition (Fruchter, Stockall, & Marantz, 2013. The present study extends this work by demonstrating that morphophonological rules impact production more generally, including the production of both regular and irregular past tense in RMI, an aphasic individual with an established morphological deficit (Rimikis & Buchwald, 2014. While we previously reported differences in production for irregular verbs with either high or low levels of lexical support, the current study further examined this phenomenon, and we found that the production of the past-tense form for both regular and irregular verbs was affected by the support for that verb’s inflectional rule . Subject RMI, 39, right-handed male with aphasia secondary to L-MCA CVA. His production includes frequent morphological errors across tasks, with semantic and phonological errors also occurring. Procedure RMI was administered a past-tense elicitation task. Sentence frames including regular and irregular verbs were presented verbally and visually (e.g.

  7. Turismo irregular

    Directory of Open Access Journals (Sweden)

    Santiago Londoño Vélez

    1992-05-01

    Full Text Available Tesoros de Cartagena. Germán Téllez y Alfredo Iriarte. El Sello editores, Bogotá, 1991. Homenaje al Cauca. Varios autores. Villegas Editores, Bogotá, 1991. Por los caminos de Caldas. Batriz Zuluaga V. y Omar Morales B. Ediciones Hoge, Bogotá (?, 1991.

  8. Irregularities Associated with Artificially Created Dusty Plasmas in the near Earth Space Environment

    Science.gov (United States)

    Bordikar, M. R.; Scales, W.; Mahmoudian, A.; Fu, H.

    2009-12-01

    A natural dust layer formed by tons of meteoric dust spans the altitude range between 80 and 100 kilometers of the earth’s upper mesosphere and lower thermosphere which forms Noctilucent Clouds NLCs. These dust layers are charged due to collection of electrons and ions from the earth’s ionosphere. Polar Mesospheric Summer Echoes are radar echoes which result from scattering from the irregularities in the electron density above the NLC altitude. An alternate approach to understanding natural dust layers is to perform active space experiments in which a dust cloud is artificially created in a controlled manner in the upper atmosphere. The goal of Charged Aerosol Release Experiment (CARE) is to investigate similarity in plasma irregularity associated with natural and artificial dust layers. This presentation will address some of the physical processes expected to be important during the early time phase after creation of an artificial dust cloud in the earth’s ionosphere. Of major importance will be the production of plasma irregularities which may lead to radar echoes and the possibility of their relationship to PMSEs observed from natural dusty space plasmas. The objective is to investigate the production of electron irregularities due to growth of plasma instabilities driven by inhomogeneities in the boundary between the background plasma and the expanding charged dust layer. First, a two dimensional plasma simulation model will be described that may be used for examining early time evolution after expansion of an artificial dust cloud across the magnetic field in the ionosphere. The model considers a three species system with fluid electrons and ions and Particle-In-Cell PIC charged dust grains in which the dust charge on the grains varies in time according to the standard charging model. The electrons are magnetized and the algorithm incorporates the parallel electron dynamics while the ions are assumed to be unmagnetized. Simulations runs were made to

  9. The Withdrawal of Health Care from Irregular Immigrants and Medical Conscientious Objection

    Directory of Open Access Journals (Sweden)

    Yolanda Garcìa Ruiz

    2016-12-01

    Full Text Available The economic crisis so strongly affecting some southern European countries has led to significant cuts in the system of universal public health care in Spain. Such measures particularly affect irregular immigrants and can also cause significant public health consequences. A form of civil resistance that deserves to be analyzed is the conscientious objection of Spanish doctors who have chosen to continue attending irregular immigrants in contravention of new the rules restricting their access to the public health system and their right to health. The aim of this paper is to analyze the new regulation which cut health care for irregular immigrants in Spain, the impact of this new regulation on the most vulnerable groups, and the response of doctors, who exercised their right to conscientious objection in relation to applying the new regulation. Finally to examine the announcement of change which came about as a consequence of international and domestic social pressure causing political risk to the Spanish National Government. La crisis económica, que ha afectado tan profundamente a algunos países del sur de Europa, ha dado lugar a significativos recortes en el sistema de atención sanitaria pública en España. Algunas de las medidas adoptadas han afectado específicamente a los inmigrantes irregulares y pueden tener, incluso, efectos en el ámbito de la salud pública. Una forma de desobediencia civil que merece ser analizada es la declaración de objeción de conciencia de determinados médicos y profesionales sanitarios españoles que han continuado atendiendo a los inmigrantes irregulares en contra de las nuevas  restricciones impuestas por el Gobierno que afectan al reconocimiento universal del derecho a la salud. El propósito de este artículo es el de analizar la nueva regulación que limita el acceso a la asistencia sanitaria de los inmigrantes irregulares en España, el impacto de esta nueva regulación en los grupos más vulnerables

  10. Mass-to-Light versus Color Relations for Dwarf Irregular Galaxies

    Science.gov (United States)

    Herrmann, Kimberly A.; Hunter, Deidre Ann; Zhang, Hong-Xin; Elmegreen, Bruce; LITTLE THINGS

    2017-01-01

    We have determined new relations between UBV colors and mass-to-light (M/L) ratios for dwarf irregular galaxies, as well as for transformed g‧ - r‧. These M/L to color relations (MLCRs) are based on stellar mass density profiles determined for 34 LITTLE THINGS dwarfs from spectral energy distribution fitting to multi-wavelength surface photometry in passbands from the FUV to the NIR. These relations can be used to determine stellar masses in dwarf irregular galaxies for situations where other determinations of stellar mass are not possible. Our MLCRs are shallower than comparable MLCRs in the literature determined for spiral galaxies. We divided our dwarf data into four metallicity bins and found indications of a steepening of the MLCR with increased oxygen abundance, perhaps due to more line blanketing occurring at higher metallicity.

  11. Causes of Irregular Energy Density in $f(R,T)$ Gravity

    CERN Document Server

    Yousaf, Z; Bhatti, M Zaeem ul Haq

    2016-01-01

    We investigate irregularity factors for a self-gravitating spherical star evolving in the presence of imperfect fluid. We explore the gravitational field equations and the dynamical equations with the systematic construction in $f(R,T)$ gravity, where $T$ is the trace of the energy-momentum tensor. Furthermore, we analyze two well-known differential equations (which occupy principal importance in the exploration of causes of energy density inhomogeneities) with the help of the Weyl tensor and the conservation laws. The irregularity factors for a spherical star are examined for particular cases of dust, isotropic and anisotropic fluids in dissipative and non-dissipative regimes in the framework of $f(R,T)$ gravity. It is found that as the complexity in the matter with the anisotropic stresses increases, the inhomogeneity factor has more correspondences to one of the structure scalars.

  12. Irregular Polyomino-Shaped Subarrays for Space-Based Active Arrays

    Directory of Open Access Journals (Sweden)

    R. J. Mailloux

    2009-01-01

    Full Text Available This paper presents new results showing the application of polyomino-based subarrays to limited field of view and wideband, wide-angle scanning. This technology can reduce the number of phase controls in arrays used for limited sector coverage or the number of time delay devices for wideband radar or communications, and so can reduce the cost of space-based active arrays. We concentrate on the wideband application. Results are presented by comparing the gain and peak sidelobe results of irregular polyomino subarray-based arrays with those of rectangular subarrays. It is shown that using irregular polyomino subarrays can result in a major decrease in sidelobes while presenting, in most cases, only a few tenths of a dB gain reduction compared to rectangular subarrays.

  13. A Numerical Algorithm for Complex Biological Flow in Irregular Microdevice Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Nonaka, A; Miller, G H; Marshall, T; Liepmann, D; Gulati, S; Trebotich, D; Colella, P

    2003-12-15

    We present a numerical algorithm to simulate non-Newtonian flow in complex microdevice components. The model consists of continuum viscoelastic incompressible flow in irregular microscale geometries. Our numerical approach is the projection method of Bell, Colella and Glaz (BCG) to impose the incompressibility constraint coupled with the polymeric stress splitting discretization of Trebotich, Colella and Miller (TCM). In this approach we exploit the hyperbolic structure of the equations of motion to achieve higher resolution in the presence of strong gradients and to gain an order of magnitude in the timestep. We also extend BCG and TCM to an embedded boundary method to treat irregular domain geometries which exist in microdevices. Our method allows for particle representation in a continuum fluid. We present preliminary results for incompressible viscous flow with comparison to flow of DNA and simulants in microchannels and other components used in chem/bio microdevices.

  14. Automatically adapted metal connections by CAD / CAM technology to the irregularities of the roundtimber

    Directory of Open Access Journals (Sweden)

    Alessandra Teribele*

    2016-06-01

    Full Text Available The round wood, material whose need for improvement is minimal, presents itself as an efficient material for use in buildings due to its physical - mechanical properties, functional versatility and respect for environmental requirements. They are characterized by unique pieces, with tapered shape and wavy longitudinal axis, dimensional irregularities that hinder junctions and enhance the importance of connections in architectural compositions. Without the processing of woodturning that keeps the diameter of the logs constant, the joints need to be adjusted to the formal irregularities of each log by hand. With the parametric modeling and the digital fabrication, this work suggests the automatic modeling of connections adapting them to the actual measurements of the logs, reducing material losses, resistance and adjustments in the process.

  15. The 3 $\\mu$m Spectrum of Jupiter's Irregular Satellite Himalia

    CERN Document Server

    Brown, M E

    2014-01-01

    We present a medium resolution spectrum of Jupiter's irregular satellite Himalia covering the critical 3 $\\mu$m spectral region. The spectrum shows no evidence for aqueously altered phyllosilicates, as had been suggested from the tentative detection of a 0.7 $\\mu$m absorption, but instead shows a spectrum strikingly similar to the C/CF type asteroid 52 Europa. 52 Europa is the prototype of a class of asteroids generally situated in the outer asteroid belt between less distant asteroids which show evidence for aqueous alteration and more distant asteroids which show evidence for water ice. The spectral match between Himalia and this group of asteroids is surprising and difficult to reconcile with models of the origin of the irregular satellites.

  16. An Efficient Heuristic Approach for Irregular Cutting Stock Problem in Ship Building Industry

    Directory of Open Access Journals (Sweden)

    Yan-xin Xu

    2016-01-01

    Full Text Available This paper presents an efficient approach for solving a real two-dimensional irregular cutting stock problem in ship building industry. Cutting stock problem is a common cutting and packing problem that arises in a variety of industrial applications. A modification of selection heuristic Exact Fit is applied in our research. In the case referring to irregular shapes, a placement heuristics is more important to construct a complete solution. A placement heuristic relating to bottom-left-fill is presented. We evaluate the proposed approach using generated instance only with convex shapes in literatures and some instances with nonconvex shapes based on real problem from ship building industry. The results demonstrate that the effectiveness and efficiency of the proposed approach are significantly better than some conventional heuristics.

  17. Irregular Firing and High-Conductance States in Spinal Motoneurons during Scratching and Swimming

    DEFF Research Database (Denmark)

    Guzulaitis, Robertas; Hounsgaard, Jorn; Alaburda, Aidas

    2016-01-01

    UNLABELLED: Intense synaptic transmission during scratch network activity increases conductance and induces irregular firing in spinal motoneurons. It is not known whether this high-conductance state is a select feature for scratching or a property that goes with spinal motor network activity...... in general. Here we compare conductance and firing patterns in spinal motoneurons during network activity for scratching and swimming in an ex vivo carapace-spinal cord preparation from adult turtles (Trachemys scripta elegans). The pattern and relative engagement of motoneurons are distinctly different...... in scratching and swimming. Nevertheless, we found increased synaptic fluctuations in membrane potential, irregular firing, and increased conductance in spinal motoneurons during scratch and swim network activity. Our finding indicates that intense synaptic activation of motoneurons is a general feature...

  18. GPS scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere

    CERN Document Server

    van der Meeren, Christer; Lorentzen, Dag; Moen, Jøran Idar; Romano, Vincenzo

    2016-01-01

    In this paper we study a tongue of ionization (TOI) on 31 October 2011 which stretched across the polar cap from the Canadian dayside sector to Svalbard in the nightside ionosphere. The TOI front arrived over Svalbard around 1930 UT. We have investigated GPS scintillation and irregularities in relation to this TOI front. This is the first study presenting such detailed multi-instrument data of scintillation and irregularities in relation to a TOI front. Combining data from an all-sky imager, the European Incoherent Scatter Svalbard Radar, the Super Dual Auroral Radar Network Hankasalmi radar, and three GPS scintillation and total electron content (TEC) monitors in Longyearbyen and Ny-{\\AA}lesund, we observe bursts of phase scintillation and no amplitude scintillation in relation to the leading gradient of the TOI. Spectrograms of 50 Hz phase measurements show highly localized and variable structuring of the TOI leading gradient, with no structuring or scintillation within the TOI or ahead of the TOI.

  19. Analysis of ionospheric irregularities during total solar eclipse 2016 based on GNSS observation

    Science.gov (United States)

    Husin, A.; Jiyo; Anggarani, S.; Ekawati, S.; Dear, V.

    2016-11-01

    A total solar eclipse occurred over Indonesia in the morning hours on 9 March 2016. Ionisations in the ionosphere which is associated with the solar radiation during the total eclipse provided a good opportunity to study the ionospheric irregularities. Using global navigation satellite system (GNSS) data taken from dual-frequency receivers in Manado, we investigated and analysed the total electron content (TEC) perturbations with a time resolution of 60 s to reveal ionospheric irregularities during total eclipse. Result showed that TEC conditions based on IPP were decreased during solar eclipse on March 9, comparing with the neighbour day. The maximum percentage deviation (DTEC) from the average value during eclipse period, 00:00 - 02:40 UT reach -41.5%. The duration of maximum decrement in TEC occurs were around 2-30 minutes after the maximum obscuration.

  20. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

    2015-02-15

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  1. Irregular Segmented Region Compression Coding Based on Pulse Coupled Neural Network

    Institute of Scientific and Technical Information of China (English)

    MA Yi-de; QI Chun-liang; QIAN Zhi-bai; SHI Fei; ZHANG Bei-dou

    2006-01-01

    An irregular segmented region coding algorithm based on pulse coupled neural network(PCNN) is presented. PCNN has the property of pulse-coupled and changeable threshold, through which these adjacent pixels with approximate gray values can be activated simultaneously. One can draw a conclusion that PCNN has the advantage of realizing the regional segmentation, and the details of original image can be achieved by the parameter adjustment of segmented images, and at the same time, the trivial segmented regions can be avoided. For the better approximation of irregular segmented regions, the Gram-Schmidt method, by which a group of orthonormal basis functions is constructed from a group of linear independent initial base functions, is adopted. Because of the orthonormal reconstructing method, the quality of reconstructed image can be greatly improved and the progressive image transmission will also be possible.

  2. Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

    Science.gov (United States)

    Wu, Xiaolan; Grubesic, Tony H.

    2010-12-01

    Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

  3. Constraining an Irregular Peptide Secondary Structure through Ring‐Closing Alkyne Metathesis

    Science.gov (United States)

    Cromm, Philipp M.; Wallraven, Kerstin; Glas, Adrian; Bier, David; Fürstner, Alois; Ottmann, Christian

    2016-01-01

    Abstract Macrocyclization can be used to constrain peptides in their bioactive conformations, thereby supporting target affinity and bioactivity. In particular, for the targeting of challenging protein–protein interactions, macrocyclic peptides have proven to be very useful. Available approaches focus on the stabilization of α‐helices, which limits their general applicability. Here we report for the first time on the use of ring‐closing alkyne metathesis for the stabilization of an irregular peptide secondary structure. A small library of alkyne‐crosslinked peptides provided a number of derivatives with improved target affinity relative to the linear parent peptide. In addition, we report the crystal structure of the highest‐affinity derivative in a complex with its protein target 14‐3‐3ζ. It can be expected that the alkyne‐based macrocyclization of irregular binding epitopes should give rise to new scaffolds suitable for targeting of currently intractable proteins. PMID:27596722

  4. It's not the voting that's democracy, it's the counting: Statistical detection of systematic election irregularities

    CERN Document Server

    Klimek, Peter; Hanel, Rudolf; Thurner, Stefan

    2012-01-01

    Democratic societies are built around the principle of free and fair elections, that each citizen's vote should count equal. National elections can be regarded as large-scale social experiments, where people are grouped into usually large numbers of electoral districts and vote according to their preferences. The large number of samples implies certain statistical consequences for the polling results which can be used to identify election irregularities. Using a suitable data collapse, we find that vote distributions of elections with alleged fraud show a kurtosis of hundred times more than normal elections. As an example we show that reported irregularities in the 2011 Duma election are indeed well explained by systematic ballot stuffing and develop a parametric model quantifying to which extent fraudulent mechanisms are present. We show that if specific statistical properties are present in an election, the results do not represent the will of the people. We formulate a parametric test detecting these stati...

  5. Artificial periodic irregularities in the high-latitude ionosphere excited by the HAARP facility

    Science.gov (United States)

    Bakhmetieva, N. V.; Grach, S. M.; Sergeev, E. N.; Shindin, A. V.; Milikh, G. M.; Siefring, C. L.; Bernhardt, P. A.; McCarrick, M.

    2016-07-01

    We present results of the new observations of artificial periodic irregularities (APIs) in the ionosphere using the High Frequency Active Auroral Research Program (HAARP) heating facility carried out in late May and early June 2014.The objective of this work is to detect API using high-latitude facility and analyze possible differences of the temporal and spatial variations of the API echoes in the high (HAARP) and middle (Sura) latitudes. Irregularities were created by the powerful wave of X mode and were sounded using the short probing pulses signals of X mode. API echoes were observed in the D, E, and F regions of the ionosphere. Amplitudes and characteristic times of the API echoes were measured. The API growth and decay times at HAARP (high latitudes) observed were similar to those at the Sura heating facility (midlatitudes).

  6. Mei symmetry and conservation laws of discrete nonholonomic dynamical systems with regular and irregular lattices

    Institute of Scientific and Technical Information of China (English)

    Zhao Gang-Ling; Chen Li-Qun; Fu Jing-Li; Hong Fang-Yu

    2013-01-01

    In this paper,Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated.Firstly,the equations of motion of discrete nonholonomic systems are introduced for regular and irregular lattices.Secondly,for cases of the two lattices,based on the invariance of the Hamiltomian functional under the infinitesimal transformation of time and generalized coordinates,we present the quasi-extremal equation,the discrete analogues of Noether identity,Noether theorems,and the Noether conservation laws of the systems.Thirdly,in cases of the two lattices,we study the Mei symmetry in which we give the discrete analogues of the criterion,the theorem,and the conservative laws of Mei symmetry for the systems.Finally,an example is discussed for the application of the results.

  7. Experimental Study on Local Scour Around A Large Circular Cylinder Under Irregular Waves

    Institute of Scientific and Technical Information of China (English)

    周益人; 陈国平

    2004-01-01

    A series of physical model tests are conducted for local scour around a circular cylinder of a relatively large diameter (0.15 < D/L < 0.5) under the action of irregular waves. The laws of change of the topography around the cylinder are systematically studied. The effects of wave height, wave period, water depth, sediment grain size and cylinder diameter are taken into account. The mechanism of formation of the topography around the cylinder is analyzed. A detailed analysis is given to bed sediment grain size, and it is considered that the depth of scour around the cylinder under wave action is not inversely proportional to the sediment grain diameter. On such a basis, an equation is proposed for calculation of the maximum depth of scour around a cylinder as well as its position under the action of irregular waves.

  8. Microscopic Receding Contact Line Dynamics on Pillar and Irregular Superhydrophobic Surfaces

    Science.gov (United States)

    Yeong, Yong Han; Milionis, Athanasios; Loth, Eric; Bayer, Ilker S.

    2015-01-01

    Receding angles have been shown to have great significance when designing a superhydrophobic surface for applications involving self-cleaning. Although apparent receding angles under dynamic conditions have been well studied, the microscopic receding contact line dynamics are not well understood. Therefore, experiments were performed to measure these dynamics on textured square pillar and irregular superhydrophobic surfaces at micron length scales and at micro-second temporal scales. Results revealed a consistent “slide-snap” motion of the microscopic receding line as compared to the “stick-slip” dynamics reported in previous studies. Interface angles between 40–60° were measured for the pre-snap receding lines on all pillar surfaces. Similar “slide-snap” dynamics were also observed on an irregular nanocomposite surface. However, the sharper features of the surface asperities resulted in a higher pre-snap receding line interface angle (~90°). PMID:25670630

  9. THE 3 μm SPECTRUM OF JUPITER's IRREGULAR SATELLITE HIMALIA

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M. E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Rhoden, A. R., E-mail: mbrown@caltech.edu, E-mail: Alyssa.Rhoden@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2014-10-01

    We present a medium resolution spectrum of Jupiter's irregular satellite Himalia covering the critical 3 μm spectral region. The spectrum shows no evidence for aqueously altered phyllosilicates, as had been suggested from the tentative detection of a 0.7 μm absorption, but instead shows a spectrum strikingly similar to the C/CF type asteroid 52 Europa. 52 Europa is the prototype of a class of asteroids generally situated in the outer asteroid belt between less distant asteroids which show evidence for aqueous alteration and more distant asteroids which show evidence for water ice. The spectral match between Himalia and this group of asteroids is surprising and difficult to reconcile with models of the origin of the irregular satellites.

  10. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease.

    Science.gov (United States)

    Rose, Martin H; Løkkegaard, Annemette; Sonne-Holm, Stig; Jensen, Bente R

    2013-04-01

    We investigated lower-extremity isometric tremor Approximate Entropy (irregularity), torque steadiness and rate of force development (RFD) and their associations to muscle activation strategy during isometric knee extensions in patients with Parkinson's disease (PD). Thirteen male patients with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD and the patients had increased muscle coactivation. A markedly lower RFD was found in PD and the decreased RFD correlated with reduced agonist muscle activation. Furthermore, patient RFD correlated with the Movement-Disorder-Society-Unified-Parkinson's-Disease-Rating-Scale 3 (motor part) scores. We concluded that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation.

  11. Comparison of Super Stuff and paraffin wax bolus in radiation therapy of irregular surfaces.

    Science.gov (United States)

    Humphries, S M; Boyd, K; Cornish, P; Newman, F D

    1996-01-01

    Irregular facial contours can make radiation therapy of head and neck tumors difficult. Isodose lines become skewed, making treatment planning complex. A traditional solution to this problem is the paraffin wax box bolus. Such a bolus is made to fit the irregular surface compensating for the topology and creating an even surface. The fabrication of a wax bolus can be a difficult and time-consuming process. A method that is simple and efficient has been devised. Super Stuff bolus can be easily molded and has approximately the same effect as a similar paraffin wax bolus. This was verified by irradiating a Rando head phantom with both a paraffin wax bolus and a Super Stuff bolus. Doses to various points of interest were measured with thermoluminescent dosimetry (TLD) chips (LiF). The particular case addressed is malignant melanoma of the nasal septum, but the technique described can be useful in the treatment of other sites as well.

  12. Clinical observation of electromagnet in vitrectomy for irregular intraocular magnetic foreign body removal

    Directory of Open Access Journals (Sweden)

    Yan-Hui Han

    2016-03-01

    Full Text Available AIM:To analyze the therapeutics effect of electromagnet in vitrectomy for irregular intraocular magnetic foreign body removal.METHODS:Clinical data of 60 cases(60 eyesfrom January 2012 to December 2013 with intraocular magnetic foreign bodies were retrospective analyzed. Thirty eyes underwent vitrectomy only, and electromagnet was applied in the other 30 eyes underwent vitrectomy. The success rate and complications in and after operations were compared between the two groups.RESULTS:Twenty-eight(93%patients had their foreign bodies removed successfully at the first time in electromagnet group and twenty(67%patients in vitrectomy group,there was statistic significant difference(χ2=5.333,P=0.021. Fewer complications happened in and after operations when electromagnet was used.CONCLUSION:The application of electromagnet shows advantage in vitrectomy for irregular intraocular magnetic foreign body removal and it deserves promotion.

  13. The infrared emission spectra of compositionally inhomogeneous aggregates composed of irregularly shaped constituents

    CERN Document Server

    Min, M; Waters, L B F M; De Koter, A

    2008-01-01

    In order to deduce properties of dust in astrophysical environments where dust growth through aggregation is important, knowledge of the way aggregated particles interact with radiation, and what information is encoded in the thermal radiation they emit, is needed. The emission characteristics are determined by the size and structure of the aggregate and the composition and shape of the constituents. We thus aim at performing computations of compositionally inhomogeneous aggregates composed of irregularly shaped constituents. In addition we aim at developing an empirical recipe to compute the optical properties of such aggregates in a fast and accurate manner. We performed CDA computations for aggregates of irregularly shaped particles with various compositions. The constituents of the aggregate are assumed to be in the Rayleigh regime, and in addition we assume that the dominant interaction of the aggregate constituents is through dipole-dipole interactions. We computed the spectral structure of the emission...

  14. Time-Scale and Time-Frequency Analyses of Irregularly Sampled Astronomical Time Series

    Directory of Open Access Journals (Sweden)

    S. Roques

    2005-09-01

    Full Text Available We evaluate the quality of spectral restoration in the case of irregular sampled signals in astronomy. We study in details a time-scale method leading to a global wavelet spectrum comparable to the Fourier period, and a time-frequency matching pursuit allowing us to identify the frequencies and to control the error propagation. In both cases, the signals are first resampled with a linear interpolation. Both results are compared with those obtained using Lomb's periodogram and using the weighted waveletZ-transform developed in astronomy for unevenly sampled variable stars observations. These approaches are applied to simulations and to light variations of four variable stars. This leads to the conclusion that the matching pursuit is more efficient for recovering the spectral contents of a pulsating star, even with a preliminary resampling. In particular, the results are almost independent of the quality of the initial irregular sampling.

  15. Coiled-Coil Irregularities and Instabilities in Group A Streptococcus M1 Are Required for Virulence

    Energy Technology Data Exchange (ETDEWEB)

    McNamara, Case; Zinkernagel, Annelies S.; Macheboeuf, Pauline; Cunningham, Madeleine W.; Nizet, Victor; Ghosh, Partho (UO-HSC); (UCSD)

    2008-07-21

    Antigenically variable M proteins are major virulence factors and immunogens of the human pathogen group A Streptococcus (GAS). Here, we report the -3 angstrom resolution structure of a GAS M1 fragment containing the regions responsible for eliciting type-specific, protective immunity and for binding fibrinogen, which promotes M1 proinflammatory and antiphagocytic functions. The structure revealed substantial irregularities and instabilities throughout the coiled coil of the M1 fragment. Similar structural irregularities occur in myosin and tropomyosin, explaining the patterns of cross-reactivity seen in autoimmune sequelae of GAS infection. Sequence idealization of a large segment of the M1 coiled coil enhanced stability but diminished fibrinogen binding, proinflammatory effects, and antibody cross-reactivity, whereas it left protective immunogenicity undiminished. Idealized M proteins appear to have promise as vaccine immunogens.

  16. CORPORATE GOVERNANCE AND ACCOUNTING IRREGULARITIES: Evidence from the Two-tiered Board Structure in Indonesia

    Directory of Open Access Journals (Sweden)

    Jaswadi JASWADI

    2012-09-01

    Full Text Available This study aims to investigate the extent to which the Indonesian corporate governance mechanism acts as an effective tool for protecting financial statements users against accounting irregularities. Considering that accounting irregularities might occur in between error and the fraud act, this study reviews the literature on minimizing the seriousness of these reporting incidences. The level of seriousness in misstatements is more severe when: (1 there is absence of financial expert(s on supervisory boards and audit committees, (2 companies have short tenured-CEOs and poor internal control systems, and (3 auditors are solely appointed by firms’ BOCs without agreement of block holders (known as referral. In addition, an examination of simultaneous effects of each corporate governance dimension reveals a general weakness of the BOCs and their audit committees. However, the BOC and audit committee could be an effective tool in mitigating reporting incidences, especially when they show high-quality collaboration.

  17. Stochastic dual-plane on-axis digital holographic imaging on irregular surfaces.

    Science.gov (United States)

    Wang, Fengpeng; Wang, Dayong; Rong, Lu; Wang, Yunxin; Zhao, Jie

    2016-05-10

    An imaging method based on dual-plane on-axis digital holography is proposed for the situation in which an object is on the irregular surface of a transparent medium. Light propagation of the object on the uneven surface of the medium is analyzed and simulated. The diffracted pattern of the object is deformed or destroyed by the refracted light of the medium. Dual-plane on-axis digital holography is used to eliminate the twin image. In order to retrieve the information lost in the reconstructed image due to destructive interference, the object is illuminated by a stochastic beam that is a speckle wave produced by a ground glass. Simulated and experimental results are presented, to demonstrate that the proposed method can be used for imaging on the irregular surface of a transparent medium.

  18. A Time-Domain Method for Separating Incident and Reflected Irregular Waves

    DEFF Research Database (Denmark)

    Frigaard, Peter; Brorsen, Michael

    In the hydraulic laboratory environment a seperation of an irregular wave field into incident waves propagating towards a structure, and reflected waves propagating away from the structure is often wanted. This is due to the fact that the response of the structure to the incident waves is target...... of the model test. Goda and Suzuki (1976) presented a frequency method for estimation of irregular incident and reflected waves in random waves. Mansard and Funke (1980) improved this method uaing a least squares technique. In the following, a time-domain method for seperating the incident waves...... and the reflected waves (SIRW-method), is presented. the method is based on the use of digital filters and can seperate the waves fields in real time....

  19. Serbian migration policy concerning irregular migration and asylum in the context of the EU integration process

    Directory of Open Access Journals (Sweden)

    Marta Stojić-Mitrović

    2016-02-01

    Full Text Available In this paper I would like to present Serbian migration policy concerning irregular migration and asylum in the context of the attempts of the Serbian state to become a member of the European Union. I would describe the history of the asylum system prior and after the implementation of the independent asylum system in Serbia in 2008. My presentation of the Serbian migration policy would be channelled by the analysis of some particular political issues, such as the externalization of the EU borders’ control, as well as some relevant elements of the European integration process, like visa liberalization. The second, more culturally specific dimension of the issue would be accessed through the demonstration of both legislative and public conceptualizations of the irregular migrants, asylum seekers and refugees in Serbia.

  20. Management of DoD Irregular Warfare (IW) and Security Force Assistance (SFA) Capabilities

    Science.gov (United States)

    2016-05-03

    manage DoD personnel with skills , training, education, and experience related to IW and SFA. DoDI 3000.11, May 3, 2016 TABLE OF CONTENTS 2...DOD INSTRUCTION 3000.11 MANAGEMENT OF DOD IRREGULAR WARFARE (IW) AND SECURITY FORCE ASSISTANCE (SFA) CAPABILITIES Originating Component...well as building the security capacity and capability of U.S. partners and allies. c. IW and SFA skills , training, education, and experience must be

  1. A new galactic chemical evolution model with dust: results for dwarf irregular galaxies and DLA systems

    Science.gov (United States)

    Gioannini, L.; Matteucci, F.; Vladilo, G.; Calura, F.

    2016-09-01

    We present a galactic chemical evolution model which adopts updated prescriptions for all the main processes governing the dust cycle. We follow in detail the evolution of the abundances of several chemical species (C, O, S, Si, Fe and Zn) in the gas and dust of a typical dwarf irregular galaxy. The dwarf irregular galaxy is assumed to evolve with a low but continuous level of star formation and experience galactic winds triggered by supernova explosions. We predict the evolution of the gas to dust ratio in such a galaxy and discuss critically the main processes involving dust, such as dust production by AGB stars and Type II SNe, destruction and accretion (gas condensation in clouds). We then apply our model to Damped Lyman-α systems which are believed to be dwarf irregulars, as witnessed by their abundance patterns. Our main conclusions are: i) we can reproduce the observed gas to dust ratio in dwarf galaxies. ii) We find that the process of dust accretion plays a fundamental role in the evolution of dust and in certain cases it becomes the dominant process in the dust cycle. On the other hand, dust destruction seems to be a negligible process in irregulars. iii) Concerning Damped Lyman-α systems, we show that the observed gas-phase abundances of silicon, normalized to volatile elements (zinc and sulfur), are in agreement with our model. iv) The abundances of iron and silicon in DLA systems suggest that the two elements undergo a different history of dust formation and evolution. Our work casts light on the nature of iron-rich dust: the observed depletion pattern of iron is well reproduced only when an additional source of iron dust is considered. Here we explore the possibility of a contribution from Type Ia SNe as well as an efficient accretion of iron nano-particles.

  2. Women with minor menstrual irregularities have increased risk of preeclampsia and low birthweight in spontaneous pregnancies

    DEFF Research Database (Denmark)

    Bonnesen, Barbara; Oddgeirsdóttir, Hanna L; Naver, Klara Vinsand

    2016-01-01

    examination-based gestational age. Outcome measures were gestational diabetes, hypertension, preeclampsia, preterm premature rupture of membranes, preterm birth, prolonged pregnancy, birthweight, umbilical artery pH ... with more than 7 days' deviation between self-reported and ultrasound examination-based gestational age were compared with women with a deviation of 7 days or less. RESULTS: Irregular menstrual cycle before conception increases the risk of preeclampsia (7.9% vs. 5.2%, p

  3. A modeling approach on why simple central pattern generators are built of irregular neurons.

    Science.gov (United States)

    Reyes, Marcelo Bussotti; Carelli, Pedro Valadão; Sartorelli, José Carlos; Pinto, Reynaldo Daniel

    2015-01-01

    The crustacean pyloric Central Pattern Generator (CPG) is a nervous circuit that endogenously provides periodic motor patterns. Even after about 40 years of intensive studies, the rhythm genesis is still not rigorously understood in this CPG, mainly because it is made of neurons with irregular intrinsic activity. Using mathematical models we addressed the question of using a network of irregularly behaving elements to generate periodic oscillations, and we show some advantages of using non-periodic neurons with intrinsic behavior in the transition from bursting to tonic spiking (as found in biological pyloric CPGs) as building components. We studied two- and three-neuron model CPGs built either with Hindmarsh-Rose or with conductance-based Hodgkin-Huxley-like model neurons. By changing a model's parameter we could span the neuron's intrinsic dynamical behavior from slow periodic bursting to fast tonic spiking, passing through a transition where irregular bursting was observed. Two-neuron CPG, half center oscillator (HCO), was obtained for each intrinsic behavior of the neurons by coupling them with mutual symmetric synaptic inhibition. Most of these HCOs presented regular antiphasic bursting activity and the changes of the bursting frequencies was studied as a function of the inhibitory synaptic strength. Among all HCOs, those made of intrinsic irregular neurons presented a wider burst frequency range while keeping a reliable regular oscillatory (bursting) behavior. HCOs of periodic neurons tended to be either hard to change their behavior with synaptic strength variations (slow periodic burster neurons) or unable to perform a physiologically meaningful rhythm (fast tonic spiking neurons). Moreover, 3-neuron CPGs with connectivity and output similar to those of the pyloric CPG presented the same results.

  4. Mathematical Model of Bridge-Linked Photovoltaic Arrays Operating Under Irregular Conditions

    OpenAIRE

    Juan D. Bastidas-Rodríguez; Carlos A. Ramos-Paja; Luz A. Trejos-Grisales

    2013-01-01

    This paper presents a mathematical procedure to model a photovoltaic array (N rows and M columns) in bridge-linked configuration operating under regular and irregular conditions. The proposed procedure uses the ideal single-diode model representation for each photovoltaic module and the Shockley equation to represent each bypass diode. To pose the system of NxM non-linear equations required to obtain the voltages of each module of the array, the proposed model apply the Kirchhoff current law ...

  5. A hermetic sealing process for large irregularly shaped hybrid microcircuit enclosures

    Science.gov (United States)

    Stahler, M. R.

    1977-01-01

    A system for sealing vacuum baked hybrids in a dry inert atmosphere using an overlapping spot resistance weld is described. A unique electrode configuration and fixturing that permits sealing of large and irregularly shaped gold plated Kovar packages to the hermeticity requirements of MIL-STD-883 was discussed. Metallurgical considerations and comparisons to laser sealing were made. Problems encountered during the development and optimization of the process were highlighted. Solutions to plating, fixturing, warpage, weld splatter and cracked bead problems are presented.

  6. Increased firing irregularity as an emergent property of neural-state transition in monkey prefrontal cortex.

    Science.gov (United States)

    Sakamoto, Kazuhiro; Katori, Yuichi; Saito, Naohiro; Yoshida, Shun; Aihara, Kazuyuki; Mushiake, Hajime

    2013-01-01

    Flexible behaviors are organized by complex neural networks in the prefrontal cortex. Recent studies have suggested that such networks exhibit multiple dynamical states, and can switch rapidly from one state to another. In many complex systems such as the brain, the early-warning signals that may predict whether a critical threshold for state transitions is approaching are extremely difficult to detect. We hypothesized that increases in firing irregularity are a crucial measure for predicting state transitions in the underlying neuronal circuits of the prefrontal cortex. We used both experimental and theoretical approaches to test this hypothesis. Experimentally, we analyzed activities of neurons in the prefrontal cortex while monkeys performed a maze task that required them to perform actions to reach a goal. We observed increased firing irregularity before the activity changed to encode goal-to-action information. Theoretically, we constructed theoretical generic neural networks and demonstrated that changes in neuronal gain on functional connectivity resulted in a loss of stability and an altered state of the networks, accompanied by increased firing irregularity. These results suggest that assessing the temporal pattern of neuronal fluctuations provides important clues regarding the state stability of the prefrontal network. We also introduce a novel scheme that the prefrontal cortex functions in a metastable state near the critical point of bifurcation. According to this scheme, firing irregularity in the prefrontal cortex indicates that the system is about to change its state and the flow of information in a flexible manner, which is essential for executive functions. This metastable and/or critical dynamical state of the prefrontal cortex may account for distractibility and loss of flexibility in the prefrontal cortex in major mental illnesses such as schizophrenia.

  7. A modeling approach on why simple central pattern generators are built of irregular neurons.

    Directory of Open Access Journals (Sweden)

    Marcelo Bussotti Reyes

    Full Text Available The crustacean pyloric Central Pattern Generator (CPG is a nervous circuit that endogenously provides periodic motor patterns. Even after about 40 years of intensive studies, the rhythm genesis is still not rigorously understood in this CPG, mainly because it is made of neurons with irregular intrinsic activity. Using mathematical models we addressed the question of using a network of irregularly behaving elements to generate periodic oscillations, and we show some advantages of using non-periodic neurons with intrinsic behavior in the transition from bursting to tonic spiking (as found in biological pyloric CPGs as building components. We studied two- and three-neuron model CPGs built either with Hindmarsh-Rose or with conductance-based Hodgkin-Huxley-like model neurons. By changing a model's parameter we could span the neuron's intrinsic dynamical behavior from slow periodic bursting to fast tonic spiking, passing through a transition where irregular bursting was observed. Two-neuron CPG, half center oscillator (HCO, was obtained for each intrinsic behavior of the neurons by coupling them with mutual symmetric synaptic inhibition. Most of these HCOs presented regular antiphasic bursting activity and the changes of the bursting frequencies was studied as a function of the inhibitory synaptic strength. Among all HCOs, those made of intrinsic irregular neurons presented a wider burst frequency range while keeping a reliable regular oscillatory (bursting behavior. HCOs of periodic neurons tended to be either hard to change their behavior with synaptic strength variations (slow periodic burster neurons or unable to perform a physiologically meaningful rhythm (fast tonic spiking neurons. Moreover, 3-neuron CPGs with connectivity and output similar to those of the pyloric CPG presented the same results.

  8. Formation of irregular rings in silica aerogel structure during the sintering process

    Directory of Open Access Journals (Sweden)

    Hinić Ivana I.

    2003-01-01

    Full Text Available Samples of low-density, highly disordered silica aerogel with initial bulk density of 0.16 g/cm3, were sintered isothermally in different time intervals at 1000ºC. Structural changes during the sintering process have been investigated by Raman spectroscopy. Defect modes of irregular three and four membered rings were observed in the Raman spectra of sintered samples.

  9. General George Crook’s development as a practitioner of irregular warfare during the Indian wars.

    Science.gov (United States)

    2017-06-09

    continue to prepare, train, and equip for large-scale peer or near-peer conventional warfare, the breadth of the republic’s history teaches that Irregular...considered many of the officers he encountered to be selfish, self- important, and worse yet, out of touch with the realities facing them. They limited...of Cottonwood generally, thereby virtually acknowledging himself whipped by a small party of Indians and leaving our citizens and their property

  10. A new galactic chemical evolution model with dust: results for dwarf irregular galaxies and DLA systems

    Science.gov (United States)

    Gioannini, L.; Matteucci, F.; Vladilo, G.; Calura, F.

    2017-01-01

    We present a galactic chemical evolution model which adopts updated prescriptions for all the main processes governing the dust cycle. We follow in detail the evolution of the abundances of several chemical species (C, O, S, Si, Fe and Zn) in the gas and dust of a typical dwarf irregular galaxy. The dwarf irregular galaxy is assumed to evolve with a low but continuous level of star formation and experience galactic winds triggered by supernova (SN) explosions. We predict the evolution of the gas to dust ratio in such a galaxy and discuss critically the main processes involving dust, such as dust production by asymptotic giant branch stars and Type II SNe, destruction and accretion (gas condensation in clouds). We then apply our model to damped Lyman α (DLA) systems which are believed to be dwarf irregulars, as witnessed by their abundance patterns. Our main conclusions are the following. (i) We can reproduce the observed gas to dust ratio in dwarf galaxies. (ii) We find that the process of dust accretion plays a fundamental role in the evolution of dust and in certain cases it becomes the dominant process in the dust cycle. On the other hand, dust destruction seems to be a negligible process in irregulars. (iii) Concerning DLA systems, we show that the observed gas-phase abundances of silicon, normalized to volatile elements (zinc and sulfur), are in agreement with our model. (iv) The abundances of iron and silicon in DLA systems suggest that the two elements undergo a different history of dust formation and evolution. Our work casts light on the nature of iron-rich dust: the observed depletion pattern of iron is well reproduced only when an additional source of iron dust is considered. Here we explore the possibility of a contribution from Type Ia SNe as well as an efficient accretion of iron nanoparticles.

  11. Are acronyms really irregular? Preserved acronym reading in a case of semantic dementia.

    Science.gov (United States)

    Playfoot, David; Izura, Cristina; Tree, Jeremy

    2013-08-01

    This paper describes the progressive performance of JD, a patient with semantic dementia, on acronym categorisation, recognition and reading aloud over a period of 18 months. Most acronyms have orthographic and phonological configurations that are different from English words (BBC, DVD, HIV). While some acronyms, the majority, are regularly pronounced letter by letter, others are pronounced in a more holistic, and irregular, way (NASA, AWOL). Semantic dementia at its moderate stage shows deficits in irregular word reading while reading accuracy for regular words and novel words is preserved. Nothing is known about acronym comprehension and reading ability in semantic dementia. Thus, in this study we explore for the first time the impact that semantic decline has on acronym recognition and reading processes. The decline in JD's semantic system led to increasingly impaired semantic categorisation and lexical decision for acronyms relative to healthy controls. However, her accuracy for reading aloud regular acronyms (i.e. those pronounced letter by letter such as BBC) remained near ceiling while reading irregular acronyms (i.e. those pronounced as mainstream words such as NASA) demonstrated impairment. It is therefore argued that consequences of semantic impairment vary across acronym types, a finding that informs our understanding of any reading account of this growing class of words. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Irregular-Moons Science Today and in Cassini's Final Three Years

    Science.gov (United States)

    Denk, T.; Mottola, S.

    2014-12-01

    The outer or irregular moons belong to the by far most numerous, but least investigated group of moons in the Saturnian system. The group is comprised of at least 38, mainly small objects which orbit at quite large distances to the planet, the rings, the inner regular moon system, and the Cassini spacecraft. As seen from Earth, their apparent visual magnitudes mainly range from ~20 to >25, the phase angles from 0 to 6°. From Cassini, some irregular moons can reach pole-axis directions, convex-hull shapes, and sidereal periods. So far, lightcurve inversion of Ymir revealed a convex shape reminiscent to a triangular prism and a spin-axis direction close to the South Ecliptic pole. The figure shows the lightcurve at 64° phase (bottom left panel), and four equatorial and two polar views of the derived shape model are shown at bottom right. Within Cassini's final three years in Saturn orbit, further observations offer the potential of pole and shape determinations for up to 15 irregular moons and up to 30 rotational periods total. These data may reveal (or already do so) hemispherical color variations, limits for object densities and sizes, pole-direction patterns, correlations of spin frequencies to orbit parameters, and hints for contact binaries or binary natures of the moons. Such information, besides its value per se, provides constraints for the investigation on the formation and evolutionary processes within the Saturnian satellite system.

  13. Irregular excitation patterns in reaction-diffusion systems due to perturbation by secondary pacemakers.

    Science.gov (United States)

    Lenk, Claudia; Einax, Mario; Maass, Philipp

    2013-04-01

    Spatiotemporal excitation patterns in the FitzHugh-Nagumo model are studied, which result from the disturbance of a primary pacemaker by a secondary pacemaker. The primary and secondary pacemakers generate regular waves with frequencies f(pace) and f(pert), respectively. The pacemakers are spatially separated, but waves emanating from them encounter each other via a small bridge. This leads to three different types I-III of irregular excitation patterns in disjunct domains of the f(pace)-f(pert) plane. Types I and II are caused by detachments of waves coming from the two pacemakers at corners of the bridge. Type III irregularities are confined to a boundary region of the system and originate from a partial penetration of the primary waves into a space, where circular wave fronts from the secondary pacemaker prevail. For this type, local frequencies can significantly exceed f(pace) and f(pert). The degree of irregularity found for the three different types is quantified by the entropy of the local frequency distribution and an order parameter for phase coherence.

  14. Numerical Simulation and Experimental Investigation on Performance of the Wells Turbine in Irregular Oscillating Flow

    Institute of Scientific and Technical Information of China (English)

    黄忠洲; 余志; 蒋念东

    2001-01-01

    The Wells turbine is an axial-flow air-turbine designed to extract energy from ocean waves. An important considera-tion is the self-starting capability of the Wells turbine, a phenomenon encountered where the turbine accelerate by itselfup to a certain speed for the best turbine performance. In order to clarify the self-starting characteristic and running per-formance of the Wells turbine in an irregular oscillating flow, a numerical simulation process is established in this paperon the rational assumption of quasi-steady flow conditions. Both self-starting characteristics and running performanceare obtained through the numerical simulation and subsequently compared with the experimental data achieved on acomputer-controlled oscillating flow test rig which could realize some irregular oscillating flow according to the specifiedspectrum. Results show that the self-starting time decreases with the increase of the significant wave height and the meanfrequency of the irregular oscillating flow. Therefore, it is possible to predict accurately the performance of the Wells tur-bine by computer simulation.

  15. Transformation-cost time-series method for analyzing irregularly sampled data.

    Science.gov (United States)

    Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G Baris; Kurths, Jürgen

    2015-06-01

    Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations-with associated costs-to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

  16. Abertura vocálica em verbos irregulares do português

    Directory of Open Access Journals (Sweden)

    Thaïs Cristófaro-Silva

    2008-07-01

    Full Text Available

    Este artigo discute um padrão inovador que ocorre em verbos irregulares da primeira conjugação no tempo presente do indicativo do português brasileiro. Tal padrão inovador apresenta uma vogal média aberta em posição tônica em verbos irregulares, como por exemplo, plan[ɛ]já em vez de plan[e]já. Argumenta-se neste artigo que as formas inovadoras ocorrem por generalização fonológica quando um padrão fonotático mais freqüente (dos verbos regulares é utilizado no lugar de um padrão menos freqüente (dos verbos irregulares. O artigo oferece evidências de que o padrão inovador ocorre em maior índice com verbos menos freqüentes.

  17. Optimizing Irregular Applications for Energy and Performance on the Tilera Many-core Architecture

    Energy Technology Data Exchange (ETDEWEB)

    Chavarría-Miranda, Daniel; Panyala, Ajay R.; Halappanavar, Mahantesh; Manzano Franco, Joseph B.; Tumeo, Antonino

    2015-05-20

    Optimizing applications simultaneously for energy and performance is a complex problem. High performance, parallel, irregular applications are notoriously hard to optimize due to their data-dependent memory accesses, lack of structured locality and complex data structures and code patterns. Irregular kernels are growing in importance in applications such as machine learning, graph analytics and combinatorial scientific computing. Performance- and energy-efficient implementation of these kernels on modern, energy efficient, multicore and many-core platforms is therefore an important and challenging problem. We present results from optimizing two irregular applications { the Louvain method for community detection (Grappolo), and high-performance conjugate gradient (HPCCG) { on the Tilera many-core system. We have significantly extended MIT's OpenTuner auto-tuning framework to conduct a detailed study of platform-independent and platform-specific optimizations to improve performance as well as reduce total energy consumption. We explore the optimization design space along three dimensions: memory layout schemes, compiler-based code transformations, and optimization of parallel loop schedules. Using auto-tuning, we demonstrate whole node energy savings of up to 41% relative to a baseline instantiation, and up to 31% relative to manually optimized variants.

  18. 3D thermal-hydraulic analysis of two irregular field joints for the ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Savoldi, Laura, E-mail: laura.savoldi@polito.it [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Bonifetto, Roberto [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy); Izquierdo, Jesus [Fusion for Energy, ES-08019 Barcelona (Spain); Le Barbier, Robin; Utin, Yuri [ITER Organization, Route de Vinon sur Verdon, CS 90 046, 13067 Saint Paul Lez Durance Cedex (France); Zanino, Roberto [Dipartimento Energia, Politecnico di Torino, I-10129 Torino (Italy)

    2015-10-15

    Highlights: • ITER vacuum vessel irregular field joints analyzed with ANSYS-FLUENT. • Steady-state thermal-hydraulic performance evaluated with 3D analysis. • Pressure drop comparable to that of regular field joints. • Acceptable hot spots on the inner shell and ports. • Heat transfer coefficient above the target value of 500 W/m{sup 2} K on the inner shell. - Abstract: In ITER, so-called “Irregular” Field Joints (IFJs) are foreseen at the interface between irregular sectors of the Vacuum Vessel (VV), which is located inside the cryostat and houses the in-vessel components. In the IFJs, a peculiar design of the equatorial port, with respect to that adopted in the Regular Field Joints (RFJs), accommodates the irregularities of the adjacent VV sectors. The IFJs are subject to nuclear heating and actively cooled by sub-cooled pressurized water flowing in a dedicated hydraulic loop, which includes the space left open by the borated In-Wall Shielding (IWS). Here we perform the 3D steady state thermal-hydraulic analysis of two different IFJs using the Computational Fluid Dynamics (CFD) software ANSYS-FLUENT{sup ®}. The water flow field, the pressure drop and the temperature maps are computed. The thermal performance of the IFJs in nominal operation is compared to that of an RFJ and it is shown that also in this case enough cooling capability is available to avoid hot spots above the design limits, while the pressure drop remains acceptably low.

  19. Outcomes of a Management Strategy in Eyes with Corneal Irregularity and Cataract

    Science.gov (United States)

    Shetty, Rohit; Paryani, Mukesh

    2016-01-01

    Purpose. To evaluate the outcomes of a management strategy in patients with irregular corneas and cataract. Methods. Six eyes of four patients presented for cataract surgery with irregular corneas following corneal refractive surgery. Topoguided ablation regularised the cornea, followed by phacoemulsification and intraocular lens implantation. Zonal keratometric coefficient of variation (ZKCV) measured structural changes and visual quality metrics measured functional improvement. Results. The mean duration after corneal refractive surgery was 7.83 ± 2.40 years. The logmar uncorrected distance visual acuity (0.67 ± 0.25) and the corrected distance visual acuity (0.38 ± 0.20) improved to 0.34 ± 0.14 and 0.18 ± 0.10, respectively. The changes in the standard deviations of the zonal keratometry values and the ZKCV were statistically significant in the 2, 3, and 4 mm zones. The changes in the Strehl ratio (ANOVA p = 0.043) were also statistically significant. Conclusions. Corneal regularisation followed by phacoemulsification resulted in lower residual refractive error with improved visual quality metrics. This strategy is a viable option in patients with symptomatic cataracts and irregular corneas. PMID:27563677

  20. A comparison between large-scale irregularities and scintillations in the polar ionosphere

    Science.gov (United States)

    Zhang, Q. H.; Wang, Y.; Jayachandran, P. T.; Lockwood, M. M.; Zhang, S.; Moen, J.; Xing, Z. Y.; Ma, Y. Z.; Lester, M.

    2016-12-01

    A comparison between large-scale ionospheric irregularities recorded in the global GPS total electron content (TEC) and scintillations observed by Canadian High Arctic Ionospheric Network (CHAIN) are pursued during a geomagnetic storm. Clear irregularities, such as storm enhanced density, middle-latitude trough and polar cap patches, are identified from the TEC maps, together with the modeling auroral oval. At the edges of these irregularities, clear scintillations appeared but their behaviors were different. Phase scintillations (σφ) were much larger than amplitude scintillations (S4) both in the SED segmented area and at the equatorward edge of the middle-latitude trough in post-noon sector, associated with the bursty flows or flow reversals. S4 and σφ were small in the polar cap with small enhancements due to the varied flows with the density gradient at the edges of polar cap patches. While S4 were much larger than σφ in the auroral oval due to the particle precipitations.

  1. The Study of Detecting Irregular Edge with Straight-Line Method

    Directory of Open Access Journals (Sweden)

    Muh-Don Hsiao

    2014-08-01

    Full Text Available This study’s main intention is to propose the best-fit line detection, Region of Interest (ROI detection and precision measuring method by using an object with an irregular edge in a high precision optical image. In general, an object with a smooth edge will actually display a very irregular and uneven gray scale distribution after being imaged by a high precision optical instrument, which may lead to a big problem if it is used in precision detection and measurement. Therefore, in this study we will individually propose the best-fit line detection, ROI detection conversion and the precision measuring method for irregular edges. The best-fit line detection is to propose two different best-fit line detection modes without affecting the computing time. The ROI detection method is to detect the region of most interest to the user and then to convert the regional line into a full-field image. For precision measurement, in this study we will propose a method for calculating the distance from the line to the edge and the distance between lines to achieve the measuring purpose.

  2. Laboratory Study of the Nonlinear Transformation of Irregular Waves over A Mild Slope

    Institute of Scientific and Technical Information of China (English)

    于博; 马玉祥; 马小舟; 董国海

    2014-01-01

    This-paper-considers-the-nonlinear-transformation-of-irregular-waves-propagating-over-a-mild-slope-(1꞉40).-Two-cases-of-irregular-waves,-which-are-mechanically-generated-based-on-JONSWAP-spectra,-are-used-for-this-purpose.-The-results-indicate-that-the-wave-heights-obey-the-Rayleigh-distribution-at-the-offshore-location;however,-in-the-shoaling-region,-the-heights-of-the-largest-waves-are-underestimated-by-the-theoretical-distributions.-In-the-surf-zone,-the-wave-heights-can-be-approximated-by-the-composite-Weibull-distribution.-In-addition,-the-nonlinear-phase-coupling-within-the-irregular-waves-is-investigated-by-the-wavelet-based-bicoherence.-The-bicoherence-spectra-reflect-that-the-number-of-frequency-modes-participating-in-the-phase-coupling-increases-with-the-decreasing-water-depth,-as-does-the-degree-of-phase-coupling.-After-the-incipient-breaking,-even-though-the-degree-of-phase-coupling-decreases,-a-great-number-of-higher-harmonic-wave-modes-are-also-involved-in-nonlinear-interactions.-Moreover,-the-summed-bicoherence-indicates-that-the-frequency-mode-related-to-the-strongest-local-nonlinear-interactions-shifts-to-higher-harmonics-with-the-decreasing-water-depth.

  3. Generating Irregular Models for 3D Spherical-Particle-Based Numerical Methods

    Directory of Open Access Journals (Sweden)

    Gang-Hai Huang

    2013-01-01

    Full Text Available The realistic representation of an irregular geological body is essential to the construction of a particle simulation model. A three-dimensional (3D sphere generator for an irregular model (SGIM, which is based on the platform of Microsoft Foundation Classes (MFC in VC++, is developed to accurately simulate the inherent discontinuities in geological bodies. OpenGL is employed to visualize the modeling in the SGIM. Three key functions, namely, the basic-model-setup function, the excavating function, and the cutting function, are implemented. An open-pit slope is simulated using the proposed model. The results demonstrate that an extremely irregular 3D model of a geological body can be generated using the SGIM and that various types of discontinuities can be inserted to cut the model. The data structure of the model that is generated by the SGIM is versatile and can be easily modified to match various numerical calculation tools. This can be helpful in the application of particle simulation methods to large-scale geoengineering projects.

  4. A new galactic chemical evolution model with dust: results for dwarf irregular galaxies and DLA systems

    CERN Document Server

    Gioannini, Lorenzo; Vladilo, Giovanni; Calura, Francesco

    2016-01-01

    We present a galactic chemical evolution model which adopts updated prescriptions for all the main processes governing the dust cycle. We follow in detail the evolution of the abundances of several chemical species (C, O, S, Si, Fe and Zn) in the gas and dust of a typical dwarf irregular galaxy. The dwarf irregular galaxy is assumed to evolve with a low but continuous level of star formation and experience galactic winds triggered by supernova explosions. We predict the evolution of the gas to dust ratio in such a galaxy and discuss critically the main processes involving dust, such as dust production by AGB stars and Type II SNe, destruction and accretion (gas condensation in clouds). We then apply our model to Damped Lyman-Alpha systems which are believed to be dwarf irregulars, as witnessed by their abundance patterns. Our main conclusions are: i) we can reproduce the observed gas to dust ratio in dwarf galaxies. ii) We find that the process of dust accretion plays a fundamental role in the evolution of du...

  5. SOME NEW FINITE DIFFERENCE METHODS FOR HELMHOLTZ EQUATIONS ON IRREGULAR DOMAINS OR WITH INTERFACES.

    Science.gov (United States)

    Wan, Xiaohai; Li, Zhilin

    2012-06-01

    Solving a Helmholtz equation Δu + λu = f efficiently is a challenge for many applications. For example, the core part of many efficient solvers for the incompressible Navier-Stokes equations is to solve one or several Helmholtz equations. In this paper, two new finite difference methods are proposed for solving Helmholtz equations on irregular domains, or with interfaces. For Helmholtz equations on irregular domains, the accuracy of the numerical solution obtained using the existing augmented immersed interface method (AIIM) may deteriorate when the magnitude of λ is large. In our new method, we use a level set function to extend the source term and the PDE to a larger domain before we apply the AIIM. For Helmholtz equations with interfaces, a new maximum principle preserving finite difference method is developed. The new method still uses the standard five-point stencil with modifications of the finite difference scheme at irregular grid points. The resulting coefficient matrix of the linear system of finite difference equations satisfies the sign property of the discrete maximum principle and can be solved efficiently using a multigrid solver. The finite difference method is also extended to handle temporal discretized equations where the solution coefficient λ is inversely proportional to the mesh size.

  6. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Directory of Open Access Journals (Sweden)

    Pablo Zuluaga-Ramírez

    2015-11-01

    Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

  7. The generation and use of numerical shape models for irregular Solar System objects

    Science.gov (United States)

    Simonelli, Damon P.; Thomas, Peter C.; Carcich, Brian T.; Veverka, Joseph

    1993-01-01

    We describe a procedure that allows the efficient generation of numerical shape models for irregular Solar System objects, where a numerical model is simply a table of evenly spaced body-centered latitudes and longitudes and their associated radii. This modeling technique uses a combination of data from limbs, terminators, and control points, and produces shape models that have some important advantages over analytical shape models. Accurate numerical shape models make it feasible to study irregular objects with a wide range of standard scientific analysis techniques. These applications include the determination of moments of inertia and surface gravity, the mapping of surface locations and structural orientations, photometric measurement and analysis, the reprojection and mosaicking of digital images, and the generation of albedo maps. The capabilities of our modeling procedure are illustrated through the development of an accurate numerical shape model for Phobos and the production of a global, high-resolution, high-pass-filtered digital image mosaic of this Martian moon. Other irregular objects that have been modeled, or are being modeled, include the asteroid Gaspra and the satellites Deimos, Amalthea, Epimetheus, Janus, Hyperion, and Proteus.

  8. Investigation of the temperature gradient instability as the source of midlatitude quiet time decameter-scale ionospheric irregularities: 1. Observations

    Science.gov (United States)

    Larquier, S.; Eltrass, A.; Mahmoudian, A.; Ruohoniemi, J. M.; Baker, J. B. H.; Scales, W. A.; Erickson, P. J.; Greenwald, R. A.

    2014-06-01

    Super Dual Auroral Radar Network (SuperDARN) radars regularly observe decameter-scale ionospheric irregularities at midlatitudes during quiet geomagnetic conditions. The mechanism responsible for the growth of such irregularities is still unknown. Previous results based on data from the Wallops SuperDARN HF radar and Incoherent Scatter Radar have suggested that the Temperature Gradient Instability (TGI) could be responsible for only part of the observed irregularities. This conclusion was reached based on the relative orientation of horizontal electron temperature and density gradients. However, the TGI theory requires driving gradients to be perpendicular to perpendicular to the geomagnetic field B. Since midlatitude field lines are approximately 20° off vertical, we have reexamined the original data and computed gradients along the meridional direction perpendicular to B. Distinctions have to be made between the topside and bottomside F region due to the strong influence of vertical gradients. We find that the TGI growth is possible in the topside F region for the duration of the experiment, even before irregularities were observed. We show that the absence of observed irregularities during favorable TGI growth conditions is not a consequence of HF propagation but of higher E region electron irregularity growth. We conclude that the TGI is a valid mechanism to explain the generation of all irregularities observed during the experiment.

  9. Identification of the plasma instabilities responsible for decameter-scale ionospheric irregularities on plasmapause field lines

    Science.gov (United States)

    Eltrass, Ahmed; Ruohoniemi, J. Michael; Mahmoudian, Alireza; Scales, Wayne; De Larquier, Sebastien; Baker, Joseph; Greenwald, Ray; Erickson, Philip

    The mid-latitude SuperDARN radars have revealed decameter-scale ionospheric irregularities during quiet geomagnetic periods that have been proposed to be responsible for the observed low-velocity Sub-Auroral Ionospheric Scatter (SAIS). The mechanism responsible for the growth of such common irregularities is still unknown. Joint measurements by Millstone Hill Incoherent Scatter Radar (ISR) and SuperDARN HF radar located at Wallops Island, Virginia reported by Greenwald et al. [2006] have determined decameter-scale irregularities with low drift velocities in the quiet-time mid-latitude night-side ionosphere. Temperature gradient instability (TGI) is investigated as the cause of irregularities associated with these SuperDARN echoes. The electrostatic dispersion relation for TGI has been extended into the kinetic regime appropriate for SuperDARN radar frequencies by including Landau damping, finite gyro-radius effects, and temperature anisotropy. This dispersion relation allows study of the TGI over a wide range of parameter regimes that have not been considered for such ionospheric applications up to this time. The calculations of electron temperature and density gradients in the direction perpendicular to the geomagnetic field have shown that the TGI growth is possible in the top-side F-region for the duration of the experiment. A time series for the growth rate has been developed for mid-latitude ionospheric irregularities observed by SuperDARN in the top-side F-region [Greenwald et al., 2006]. This time series is computed for both perpendicular and meridional density and temperature gradients. These observations show the role of TGI is dominant over the gradient drift instability (GDI) in this case. Nonlinear evolution of the TGI has been studied utilizing gyro-kinetic "Particle In Cell" (PIC) simulations with Monte Carlo collisions. This allows detailed study of saturation amplitude, particle flux, heat flux, diffusion coefficient, and thermal diffusivity of the

  10. Reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LI Yucheng; TENG Bin; MA Baolian

    2007-01-01

    The reflection of regular and irregular waves from a partially perforated caisson breakwater with a rock-filled core is examined. The present mathematical model is developed by means of the matched eigenfunction method. Numerical results of the present model are compared with the experimental data of different researchers. Numerical examples are given to examine the effect of rock fill on the reflection coefficient. The differences between regular and irregular waves are also investigated by means of theoretical and experimental results. It is found that the minimum reflection coefficient of irregular waves is larger than that of corresponding regular waves, but the contrary is the case for the maximum reflection coefficient.

  11. Propagation of Love-Type Wave in Porous Medium over an Orthotropic Semi-Infinite Medium with Rectangular Irregularity

    OpenAIRE

    Pramod Kumar Vaishnav; Santimoy Kundu; Shishir Gupta; Anup Saha

    2016-01-01

    Propagation of Love-type wave in an initially stressed porous medium over a semi-infinite orthotropic medium with the irregular interface has been studied. The method of separation of variables has been adopted to get the dispersion relation of Love-type wave. The irregularity is assumed to be rectangular at the interface of the layer and half-space. Finally, the dispersion relation of Love wave has been obtained in classical form. The presence of porosity, irregularity, and initial stress in...

  12. A new Fortran 90 program to compute regular and irregular associated Legendre functions

    Science.gov (United States)

    Schneider, Barry I.; Segura, Javier; Gil, Amparo; Guan, Xiaoxu; Bartschat, Klaus

    2010-12-01

    We present a modern Fortran 90 code to compute the regular Plm(x) and irregular Qlm(x) associated Legendre functions for all x∈(-1,+1) (on the cut) and |x|>1 and integer degree ( l) and order ( m). The code applies either forward or backward recursion in ( l) and ( m) in the stable direction, starting with analytically known values for forward recursion and considering both a Wronskian based and a modified Miller's method for backward recursion. While some Fortran 77 codes existed for computing the functions off the cut, no Fortran 90 code was available for accurately computing the functions for all real values of x different from x=±1 where the irregular functions are not defined. Program summaryProgram title: Associated Legendre Functions Catalogue identifier: AEHE_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHE_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 6722 No. of bytes in distributed program, including test data, etc.: 310 210 Distribution format: tar.gz Programming language: Fortran 90 Computer: Linux systems Operating system: Linux RAM: bytes Classification: 4.7 Nature of problem: Compute the regular and irregular associated Legendre functions for integer values of the degree and order and for all real arguments. The computation of the interaction of two electrons, 1/|r-r|, in prolate spheroidal coordinates is used as one example where these functions are required for all values of the argument and we are able to easily compare the series expansion in associated Legendre functions and the exact value. Solution method: The code evaluates the regular and irregular associated Legendre functions using forward recursion when |x|<1 starting the recursion with the analytically known values of the first two members of the sequence. For values of

  13. Numerical Simulation of the Time Evolution of Small-Scale Irregularities in the F-Layer Ionospheric Plasma

    Directory of Open Access Journals (Sweden)

    O. V. Mingalev

    2011-01-01

    Full Text Available Dynamics of magnetic field-aligned small-scale irregularities in the electron concentration, existing in the F-layer ionospheric plasma, is investigated with the help of a mathematical model. The plasma is assumed to be a rarefied compound consisting of electrons and positive ions and being in a strong, external magnetic field. In the applied model, kinetic processes in the plasma are simulated by using the Vlasov-Poisson system of equations. The system of equations is numerically solved applying a macroparticle method. The time evolution of a plasma irregularity, having initial cross-section dimension commensurable with a Debye length, is simulated during the period sufficient for the irregularity to decay completely. The results of simulation indicate that the small-scale irregularity, created initially in the F-region ionosphere, decays accomplishing periodic damped vibrations, with the process being collisionless.

  14. Triangulated Irregular Networks (TIN), Published in 2005, 1:600 (1in=50ft) scale, Oconto County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from LIDAR information as of 2005. Data by this...

  15. Triangulated Irregular Networks (TIN), TIN Bayfield County, Published in 2008, 1:24000 (1in=2000ft) scale, Bayfield County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Orthoimagery information as of 2008....

  16. Structural mass irregularities and fiber volume influence on morphology and mechanical properties of unsaturated polyester resin in matrix composi

    Directory of Open Access Journals (Sweden)

    Khalil Ahmed

    2015-11-01

    Full Text Available This paper presents the comparative results of a current study on unsaturated polyester resin (UPR matrix composites processed by filament winding method, with cotton spun yarn of different mass irregularities and two different volume fractions. Physical and mechanical properties were measured, namely ultimate stress, stiffness, elongation%. The mechanical properties of the composites increased significantly with the increase in the fiber volume fraction in agreement with the Counto model. Mass irregularities in the yarn structure were quantitatively measured and visualized by scanning electron microscopy (SEM. Mass irregularities cause marked decrease in relative strength about 25% and 33% which increases with fiber volume fraction. Ultimate stress and stiffness increases with fiber volume fraction and is always higher for yarn with less mass irregularities.

  17. Triangulated Irregular Networks (TIN), Published in 2000, 1:1200 (1in=100ft) scale, Brown County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Triangulated Irregular Networks (TIN) dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2000....

  18. Propagation of Love-Type Wave in Porous Medium over an Orthotropic Semi-Infinite Medium with Rectangular Irregularity

    Directory of Open Access Journals (Sweden)

    Pramod Kumar Vaishnav

    2016-01-01

    Full Text Available Propagation of Love-type wave in an initially stressed porous medium over a semi-infinite orthotropic medium with the irregular interface has been studied. The method of separation of variables has been adopted to get the dispersion relation of Love-type wave. The irregularity is assumed to be rectangular at the interface of the layer and half-space. Finally, the dispersion relation of Love wave has been obtained in classical form. The presence of porosity, irregularity, and initial stress in the dispersion equation approves the significant effect of these parameters in the propagation of Love-type waves in porous medium bounded below by an orthotropic half-space. The scientific effect of porosity, irregularity, and initial stress in the phase velocity of the Love-type wave propagation has been studied and shown graphically.

  19. A 2.5D finite element approach for predicting ground vibrations generated by vertical track irregularities

    Institute of Scientific and Technical Information of China (English)

    Xue-cheng BIAN; Chang CHAO; Wan-feng JIN; Yun-min CHEN

    2011-01-01

    Dynamic responses of track structure and wave propagation in nearby ground vibration become significant when train operates on high speeds.A train-track-ground dynamic interaction analysis model based on the 2.5D finite element method is developed for the prediction of ground vibrations due to vertical track irregularities.The one-quarter car model is used to represent the train as lumped masses connected by springs.The embankment and the underlying ground are modeled by the 2.5D finite element approach to improve the computation efficiency.The Fourier transform is applied in the direction of train's movement to express the wave motion with a wave-number.The one-quarter car model is coupled into the global stiffness matrix describing the track-ground dynamic system with the displacement compatibility condition at the wheel-rail interface,including the irregularities on the track surface.Dynamic responses of the track and ground due to train's moving loads are obtained in the wave-number domain by solving the governing equation,using a conventional finite element procedure.The amplitude and wavelength are identified as two major parameters describing track irregularities.The irregularity amplitude has a direct impact on the vertical response for low-speed trains,both for short wavelength and long wavelength irregularities.Track irregularity with shorter wavelength can generate stronger track vibration both for low-speed and high-speed cases.For low-speed case,vibrations induced by track irregularities dominate far field responses.For high-speed case,the wavelength of track irregularities has very little effect on ground vibration at distances far from track center,and train's wheel axle weights becomes dominant.

  20. Active control of interior noise within an irregular enclosure under the cooperation of point force and incident wave

    Institute of Scientific and Technical Information of China (English)

    GENG Houcai; RAO Zhushi; HAN Zushun; ZHANG Hualiang

    2002-01-01

    A new modeling method is developed for the active control of interior noise within an irregular three-dimensional cavity under the cooperation of point force and incident wave. The validity of this method is verified by a regular cuboid enclosure. With global and local per-formance functions, good results are obtained in the active control of noise within the irregular enclosure according to numerical investigations.

  1. Magnetic storm effect on the occurrence of ionospheric irregularities at an equatorial station in the African sector

    Directory of Open Access Journals (Sweden)

    Olushola Abel Oladipo

    2014-01-01

    Full Text Available Large-scale ionospheric irregularities usually measured by GPS TEC fluctuation indices are regular occurrence at the equatorial region shortly after sunset around solar maximum. Magnetic storm can trigger or inhibit the generation of these irregularities depending on the local time the main phase of a particular storm occurs. We studied the effect of nine (9 distinct storms on the occurrence of ionospheric irregularities at Fraceville in Gabon (Lat = −1.63˚, Long = 13.55˚, dip lat. = −15.94˚, an equatorial station in the African sector. These storms occurred between November 2001 and September 2002. We used TEC fluctuation indices (i.e. ROTI and ROTIAVE estimated from 30 s interval Rinex data and also we used the storm indices (i.e. Dst, dDst/dt, and IMF BZ to predict the likely effect of each storm on the irregularities occurrence at this station. The results obtained showed that most of the storms studied inhibited ionospheric irregularities. Only one out of all the storms studied (i.e. September 4, 2002 storms with the main phase on the night of September 7-8 triggered post-midnight ionospheric irregularities. There are two of the storms during which ionospheric irregularities were observed. However, these may not be solely attributed to the storms event because the level of irregularities observed during these two storms is comparable to that observed during previous days before the storms. For this station and for the storms investigated, it seems like a little modification to the use of Aarons categories in terms of the local time the maximum negative Dst occurs could lead to a better prediction. However, it would require investigating many storms during different level of solar activities and at different latitudes to generalize this modification.

  2. The relationship of Veillonella spp and C.coccoides subgroup levels in gut microbiota with type 2 diabetes mellitus in Uygurs and Kazaks of Xinjiang%新疆维、哈两民族粪样中韦荣球菌属和梭菌属水平与2型糖尿病的相关性研究

    Institute of Scientific and Technical Information of China (English)

    赵海霞; 李琳琳; 毛新民; 张瑞; 熊建会; 王烨

    2015-01-01

    目的 探讨目标差异肠道菌群与新疆维吾尔族、哈萨克族2型糖尿病(T2DM)的相关性.方法 采用16S rDNA实时荧光定量PCR对新疆维吾尔族、哈萨克族正常糖耐量及2型糖尿病患者粪样中韦荣球菌属和梭菌属水平进行检测.两组间均数比较采用t检验,运用Pearson分析方法对差异肠道菌群与新疆维、哈两民族正常糖耐量及2型糖尿病人群的体检及生化指标进行相关性分析.结果 (1) 16S rDNA实时定量PCR结果显示,韦荣球菌属及梭菌属水平在哈萨克族2型糖尿病组粪样中显著高于该民族正常糖耐量组(P =0.035,P=0.028).(2)新疆维吾尔族、哈萨克族正常糖耐量人群和2型糖尿病人群粪样中韦荣球菌属水平与体重及体重指数(BMI)显著正相关(r=0.469,P=0.009;r =0.623,P=0.002),与高密度脂蛋白胆固醇(HDL-C)水平显著负相关(r=-0.466,P=0.025);梭菌属水平与体重、空腹血糖(FBG)、甘油三酯(TG)水平显著正相关(r =0.375,P=0.049;r=0.398,P=0.033;r=0.375,P=0.041).结论 肠道中Veillonella spp和C.coccoides subgroup水平的变化可能与新疆哈萨克族、维吾尔族2型糖尿病的发病有关,需进一步深入探讨.

  3. FtsZ-Dependent Elongation of a Coccoid Bacterium

    Directory of Open Access Journals (Sweden)

    Ana R. Pereira

    2016-09-01

    Full Text Available A mechanistic understanding of the determination and maintenance of the simplest bacterial cell shape, a sphere, remains elusive compared with that of more complex shapes. Cocci seem to lack a dedicated elongation machinery, and a spherical shape has been considered an evolutionary dead-end morphology, as a transition from a spherical to a rod-like shape has never been observed in bacteria. Here we show that a Staphylococcus aureus mutant (M5 expressing the ftsZG193D allele exhibits elongated cells. Molecular dynamics simulations and in vitro studies indicate that FtsZG193D filaments are more twisted and shorter than wild-type filaments. In vivo, M5 cell wall deposition is initiated asymmetrically, only on one side of the cell, and progresses into a helical pattern rather than into a constricting ring as in wild-type cells. This helical pattern of wall insertion leads to elongation, as in rod-shaped cells. Thus, structural flexibility of FtsZ filaments can result in an FtsZ-dependent mechanism for generating elongated cells from cocci.

  4. Helicobacter pylori-coccoid forms and biofilm formation

    DEFF Research Database (Denmark)

    Andersen, Leif Percival; Rasmussen, Lone

    2009-01-01

    be detected by PCR in water supplies. There is no substantial evidence for viable H. pylori persisting in water supplies. Epidemiological studies suggest that environmental water is a risk factor for H. pylori infection when compared with tap water, and formation of H. pylori biofilm cannot be excluded....... Helicobacter pylori does not seem to take part in biofilm formation in the oral cavity even though the bacterium may be detected....

  5. FtsZ-Dependent Elongation of a Coccoid Bacterium

    NARCIS (Netherlands)

    Pereira, Ana R; Hsin, Jen; Król, Ewa; Tavares, Andreia C; Flores, Pierre; Hoiczyk, Egbert; Ng, Natalie; Dajkovic, Alex; Brun, Yves V; VanNieuwenhze, Michael S; Roemer, Terry; Carballido-Lopez, Rut; Scheffers, Dirk-Jan; Huang, Kerwyn Casey; Pinho, Mariana G

    2016-01-01

    UNLABELLED: A mechanistic understanding of the determination and maintenance of the simplest bacterial cell shape, a sphere, remains elusive compared with that of more complex shapes. Cocci seem to lack a dedicated elongation machinery, and a spherical shape has been considered an evolutionary dead-

  6. Caring for the Unseen: Using Linking Social Capital to Improve Healthcare Access to Irregular Migrants in Spain

    Science.gov (United States)

    2016-01-01

    Abstract Purpose To describe a novel strategy using linking social capital to provide healthcare access to irregular migrants with low literacy, low numeracy, and limited cultural assimilation in a European metropolitan area. Organizing Construct Public data show numerous shortcomings in meeting the healthcare needs of refugees and irregular migrants surging into Europe. Many irregular migrants living in European communities are unable to access information, care, or services due to lack of social capital. An overview of the problem and traditional charity strategies, including their barriers, are briefly described. A novel strategy using linking social capital to improve healthcare access of irregular migrants is explored and described. Information regarding the impact of this approach on the target population is provided. The discussion of nursing's role in employing linking social capital to care for the vulnerable is presented. Conclusions Immigration and refugee data show that issues related to migration will continue. The novel strategy presented can be implemented by nurses with limited financial and physical resources in small community settings frequented by irregular migrants to improve health care. Clinical Relevance The health and well‐being of irregular migrants has an impact on community health. Nurses must be aware of and consider implementing novel strategies to ensure that all community members’ healthcare needs, which are a basic human right, are addressed. PMID:27355488

  7. Efficacy of Treatment Acceptance and Commitment and Emotion Regulation Strategies on Anxiety Sensitivity, Excitement Irregularities and Self-Efficacy

    Directory of Open Access Journals (Sweden)

    Eshrat Krimi Afshar

    2016-11-01

    Full Text Available The present study was to evaluate and compare the efficacy of treatment acceptance and commitment therapy based on cognitive emotion regulation strategies on the sensitivity of anxiety, excitement irregularities and efficacy in patients with chronic headache disorder. For this purpose, in a single subject multiple baselines pre-test and posttest and follow-upin two groups, 3 patients with chronic pain who were referred to health centers in Kerman using the sampling method Selected and randomly divided and were assigned into two experimental groups. The group initially sensitivity of anxiety, excitement irregularities and self-efficacy were tested. The training is based on acceptance and commitment therapy and cognitive emotion regulation strategies were presented and then after completing the training program and follow-upperiod, both in terms of sensitivity, anxiety, excitement irregularities and self-efficacy were tested. Results: Analysis of data by the method of Cohen's effect size indicators was showed that acceptance and commitment therapy based on reducing anxiety sensitivity, excitement irregularities and increase self-efficacy in disarray and the treatment based on cognitive emotion regulation strategies has not affecting on reducing anxiety sensitivity and excitement irregularities and the self-efficacy. The cognitive and behavioral intervention (acceptance and commitment cognitive emotion regulation was significant in reducing anxiety sensitivity and excitement irregularities of migraine headaches and tension.

  8. The arbuscular mycorrhizal fungus, Glomus irregulare, controls the mycotoxin production of Fusarium sambucinum in the pathogenesis of potato.

    Science.gov (United States)

    Ismail, Youssef; McCormick, Susan; Hijri, Mohamed

    2013-11-01

    Trichothecenes are an important family of mycotoxins produced by several species of the genus Fusarium. These fungi cause serious disease on infected plants and postharvest storage of crops, and the toxins can cause health problems for humans and animals. Unfortunately, there are few methods for controlling mycotoxin production by fungal pathogens, and most rely on chemicals, creating therefore subsequent problems of chemical resistance. We tested the impact of the symbiotic arbuscular mycorrhizal fungus Glomus irregulare on a trichothecene-producing strain of Fusarium sambucinum isolated from naturally infected potato plants. Using dual in vitro cultures, we showed that G. irregulare inhibited the growth of F. sambucinum and significantly reduced the production of the trichothecene 4, 15-diacetoxyscirpenol (DAS). Furthermore, using G. irregulare-colonized potato plants infected with F. sambucinum, we found that the G. irregulare treatment inhibited the production of DAS in roots and tubers. Thus, in addition to the known beneficial effect of mycorrhizal symbiosis on plant growth, we found that G. irregulare controlled the growth of a virulent fungal pathogen and reduced production of a mycotoxin. This previously undescribed, biological control of Fusarium mycotoxin production by G. irregulare has potential implications for improved potato crop production and food safety.

  9. Menarche delay and menstrual irregularities persist in adolescents with type 1 diabetes

    Directory of Open Access Journals (Sweden)

    McFann Kim

    2011-05-01

    Full Text Available Abstract Background Menarche delay has been reported in adolescent females with type 1 diabetes (T1DM, perhaps due to poor glycemic control. We sought to compare age at menarche between adolescent females with T1DM and national data, and to identify factors associated with delayed menarche and menstrual irregularity in T1DM. Methods This was a cross-sectional study and females ages 12- 24 years (n = 228 with at least one menstrual period were recruited during their outpatient diabetes clinic appointment. The National Health and Nutrition Examination Survey (NHANES 2001-2006 data (n = 3690 for females 12-24 years were used as a control group. Results Age at menarche was later in adolescent females with T1DM diagnosed prior to menarche (12.81 +/- 0.09 years (mean+/- SE (n = 185 than for adolescent females diagnosed after menarche (12.17 0.19 years, p = 0.0015 (n = 43. Average age of menarche in NHANES was 12.27 +/- 0.038 years, which was significantly earlier than adolescent females with T1DM prior to menarche (p p = 0.77. Older age at menarche was negatively correlated with BMI z-score (r = -0.23 p = 0.0029 but not hemoglobin A1c (A1c at menarche (r = 0.01, p = 0.91. Among 181 adolescent females who were at least 2 years post menarche, 63 (35% reported usually or always irregular cycles. Conclusion Adolescent females with T1DM had a later onset of menarche than both adolescent females who developed T1DM after menarche and NHANES data. Menarche age was negatively associated with BMI z-score, but not A1c. Despite improved treatment in recent decades, menarche delay and high prevalence of menstrual irregularity is still observed among adolescent females with T1DM.

  10. Evaluation of head movement periodicity and irregularity during locomotion of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Ryuzo eShingai

    2013-03-01

    Full Text Available Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx or 50% (the mid-body point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.

  11. DC Electric Fields, Associated Plasma Drifts, and Irregularities Observed on the C/NOFS Satellite

    Science.gov (United States)

    Pfaff, R.; Freudenreich, H.; Klenzing, J.

    2011-01-01

    Results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics

  12. Modelling of ionospheric irregularities during geomagnetic storms over African low latitude region

    Science.gov (United States)

    Mungufeni, Patrick

    2016-07-01

    In this study, empirical models of occurrence of ionospheric irregularities over low latitude African region during geomagnetic storms have been developed. The geomagnetic storms considered consisted of Dst ≤ -50 nT. GNSS-derived ionospheric Total Electron Content (TEC) data over Libreville, Gabon (NKLG) (0.35° N, 9.68° E, geographic, 8.05° S, magnetic) and Malindi, Kenya (MAL2) (2.99° S, 40.19° E, geographic, 12.42° S, magnetic) during 2000 - 2014 were used. Ionospheric irregularities at scale- lengths of a few kilometers and ˜400 m were represented with the rate of change of TEC index (ROTI). The inputs for the models are the local time, solar flux index, Auroral Electrojet index, day of the year, and the Dst index, while the output is the median ROTI during these given conditions. To develop the models, the ROTI index values were binned based on the input parameters and cubic B splines were then fitted to the binned data. Developed models using data over NKLG and MAL2 were validated with independent data over stations within 510 km and 680 km radius, respectively. The models captured the enhancements and inhibitions of the occurrence of the ionospheric irregularities during the storm period. The models even emulated these patterns in the various seasons, during medium and high solar activity conditions. The correlation coefficients for the validations were statistically significant and ranged from 0.58 - 0.73, while the percentage of the variance in the observed data explained by the modelled data ranged from 34 - 53.

  13. Visual information about past, current and future properties of irregular target paths in isometric force tracking.

    Science.gov (United States)

    Mazich, Molly M; Studenka, Breanna E; Newell, Karl M

    2015-01-01

    In visual-motor tracking, information about past, current, and future properties of a target path can be available but, because they are typically manipulated independently, the relative contribution of these information categories to tracking performance is not well understood. The aim of the current study was to investigate the role of visual information pertaining to past, current, and future states of the target path in guiding isometric tracking performance as a function of the irregularity of the target path (sine wave, brown/pink noise, white noise). The findings from local and global properties of the force output showed that the role of visual information about the past, current, and future states of target paths is dependent on the regularity of the signal to be tracked. The brown/pink noise pathway condition was most strongly influenced by future and past-future visual information for both local error properties (lead/lag, root mean square error (RMSE)) and global properties of the force output (ApEn, cross correlation). The highly irregular white noise pathway did not benefit from past or future information and the highly regular sine wave was only influenced for the local error properties of RMSE and lead/lag. It appears that visual information about past and future tracking states is more effective with a pathway that is middling with respect to regularity/irregularity. This is consistent with the role of visual information in tracking to be dependent on the potential adaptability for change in the dimension of the motor output.

  14. The prevalence, causes, and relativity of dental anxiety in adult patients to irregular dental visits.

    Science.gov (United States)

    Gaffar, Balgis O; Alagl, Adel S; Al-Ansari, Asim A

    2014-06-01

    To assess the frequency and causes of dental anxiety and their relation to irregular dental visits among adult dental patients. The Dental Anxiety Question (DAQ) included within a self-administered questionnaire was distributed to 1025 patients attending the Interns' Dental Clinics in the Department of Preventive Dental Sciences, College of Dentistry, University of Dammam, Dammam, Kingdom of Saudi Arabia from March 2012 to February 2013. A cross-sectional study design was used. The questionnaire consisted of 22 closed-ended questions divided into 4 sections; 1) demographics, 2) regularity of dental visits, and related causes, 3) DAQ, cancellation of dental appointments, history of previous trauma, dental anxiety provoking factors within dental environment and procedures, and 4) patients' status in dental clinics, preferences of dentists, and perceptions regarding dental anxiety. The prevalence of dental anxiety among the study sample was 27%. Anesthetic injection was the main factor of dental fear (88.2%), while dental surgical procedures (35.7%) and extractions (23%) were the most terrifying dental procedures. Lack of time (79.5%), cost (71.5%), far-situated dental services (62.2%), and fear (57.1%) were causes listed for irregular dental visits; while 31.3% had no specific reason. Irregular dental visits were not related to dental anxiety. Dental anxiety continues to be an obstacle despite the vast improvement in dentistry; and this raises an alert regarding personal and communication factors in the patient-dentist relationship. Factors such as equal distribution of dental services, time, and cost should also be addressed.

  15. Modeling of aluminum-silicon irregular eutectic growth by cellular automaton model

    Directory of Open Access Journals (Sweden)

    Rui Chen

    2016-03-01

    Full Text Available Due to the extensive application of Al-Si alloys in the automotive and aerospace industries as structural components, an understanding of their microstructural formation, such as dendrite and (Al+Si eutectic, is of great importance to control the desirable microstructure, so as to modify the performance of castings. Since previous major themes of microstructural simulation are dendrite and regular eutectic growth, few efforts have been paid to simulate the irregular eutectic growth. Therefore, a multiphase cellular automaton (CA model is developed and applied to simulate the time-dependent Al-Si irregular eutectic growth. Prior to model establishment, related experiments were carried out to investigate the influence of cooling rate and Sr modification on the growth of eutectic Si. This CA model incorporates several aspects, including growth algorithms and nucleation criterion, to achieve the competitive and cooperative growth mechanism for nonfaceted-faceted Al-Si irregular eutectic. The growth kinetics considers thermal undercooling, constitutional undercooling, and curvature undercooling, as well as the anisotropic characteristic of eutectic Si growth. The capturing rule takes into account the effects of modification on the silicon growth behaviors. The simulated results indicate that for unmodified alloy, the higher eutectic undercooling results in the higher eutectic growth velocity, and a more refined eutectic microstructure as well as narrower eutectic lamellar spacing. For modified alloy, the eutectic silicon tends to be obvious fibrous morphology and the morphology of eutectic Si is determined by both chemical modifier and cooling rate. The predicted microstructure of Al-7Si alloy under different solidification conditions shows that this proposed model can successfully reproduce both dendrite and eutectic microstructures.

  16. Sub-Auroral Ion Drifts as a Source of Mid-Latitude Plasma Density Irregularities

    Science.gov (United States)

    Sotnikov, V.; Kim, T.; Mishin, E.; Paraschiv, I.; Rose, D.

    Ionospheric irregularities cause scintillations of electromagnetic signals that can severely affect navigation and transionospheric communication, in particular during space storms. At midlatitudes, such space weather events are caused mainly by subauroral electric field structures (SAID/SAPS) [1, 2]. SAID/SAPS -related shear flows and plasma density troughs point to interchange and Kelvin-Helmholtz type instabilities as a possible source of plasma irregularities. A model of nonlinear development of these instabilities based on the two-fluid hydrodynamic description with inclusion of finite Larmor radius effects will be presented. A numerical code in C language to solve the derived nonlinear equations for analysis of interchange and flow velocity shear instabilities in the ionosphere was developed. This code was used to analyze competition between interchange and Kelvin Helmholtz instabilities in the equatorial region [3]. The high-resolution simulations with continuous density and velocity profiles will be driven by the ambient conditions corresponding to the in situ Defence Military Satellite Program (DMSP) satellite low-resolution data [2] during UHF/GPS L-band subauroral scintillation events. [1] Mishin, E. (2013), Interaction of substorm injections with the subauroral geospace: 1. Multispacecraft observations of SAID, J. Geophys. Res. Space Phys., 118, 5782-5796, doi:10.1002/jgra.50548. [2] Mishin, E., and N. Blaunstein (2008), Irregularities within subauroral polarization stream-related troughs and GPS radio interference at midlatitudes. In: T. Fuller-Rowell et al. (eds), AGU Geophysical Monograph 181, MidLatitude Ionospheric Dynamics and Disturbances, pp. 291-295, doi:10.1029/181GM26, Washington, DC, USA. [3] V. Sotnikov, T. Kim, E. Mishin, T. Genoni, D. Rose, I. Paraschiv, Development of a Flow Velocity Shear Instability in the Presence of Finite Larmor Radius Effects, AGU Fall Meeting, San Francisco, 15 - 19 December, 2014.

  17. Implications of mitotic and meiotic irregularities in common beans (Phaseolus vulgaris L.).

    Science.gov (United States)

    Lima, D C; Braz, G T; Dos Reis, G B; Techio, V H; Davide, L C; de F B Abreu, A

    2016-05-23

    The common bean has great social and economic importance in Brazil and is the subject of a high number of publications, especially in the fields of genetics and breeding. Breeding programs aim to increase grain yield; however, mitosis and meiosis represent under explored research areas that have a direct impact on grain yield. Therefore, the study of cell division could be another tool available to bean geneticists and breeders. The aim of this study was to investigate irregularities occurring during the cell cycle and meiosis in common bean. The common bean cultivar used was BRSMG Talismã, which owing to its high yield and grain quality is recommended for cultivation in Brazil. We classified the interphase nuclei, estimated the mitotic and meiotic index, grain pollen viability, and percentage of abnormalities in both processes. The mitotic index was 4.1%, the interphase nucleus was non-reticulated, and 19% of dividing somatic cells showed abnormal behavior. Meiosis also presented irregularities resulting in a meiotic index of 44.6%. Viability of pollen grains was 94.3%. These results indicate that the common bean cultivar BRSMG Talismã possesses repair mechanisms that compensate for changes by producing a large number of pollen grains. Another important strategy adopted by bean plants to ensure stability is the elimination of abnormal cells by apoptosis. As the common bean cultivar BRSMG Talismã is recommended for cultivation because of its good agronomic performance, it can be concluded that mitotic and meiotic irregularities have no negative influence on its grain quality and yield.

  18. Modeling of aluminum-silicon irregular eutectic growth by cellular automaton model

    Institute of Scientific and Technical Information of China (English)

    Rui Chen; Qing-yan Xu; Bai-cheng Liu

    2016-01-01

    Due to the extensive application of Al-Si aloys in the automotive and aerospace industries as structural components, an understanding of their microstructural formation, such as dendrite and (Al+Si) eutectic, is of great importance to control the desirable microstructure, so as to modify the performance of castings. Since previous major themes of microstructural simulation are dendrite and regular eutectic growth, few efforts have been paid to simulate the irregular eutectic growth. Therefore, a multiphase celular automaton (CA) model is developed and applied to simulate the time-dependent Al-Si irregular eutectic growth. Prior to model establishment, related experiments were carried out to investigate the inlfuence of cooling rate and Sr modiifcation on the growth of eutectic Si. This CA model incorporates several aspects, including growth algorithms and nucleation criterion, to achieve the competitive and cooperative growth mechanism for nonfaceted-faceted Al-Si irregular eutectic. The growth kinetics considers thermal undercooling, constitutional undercooling, and curvature undercooling, as wel as the anisotropic characteristic of eutectic Si growth. The capturing rule takes into account the effects of modiifcation on the silicon growth behaviors. The simulated results indicate that for unmodiifed aloy, the higher eutectic undercooling results in the higher eutectic growth velocity, and a more reifned eutectic microstructure as wel as narrower eutectic lamelar spacing. For modiifed aloy, the eutectic silicon tends to be obvious ifbrous morphology and the morphology of eutectic Si is determined by both chemical modiifer and cooling rate. The predicted microstructure of Al-7Si aloy under different solidiifcation conditions shows that this proposed model can successfuly reproduce both dendrite and eutectic microstructures.

  19. DEMETER Observations of Highly Structured Plasma Density and Associated ELF Electric Field and Magnetic Field Irregularities at Middle and Low Latitudes

    Science.gov (United States)

    Pfaff, R.; Liebrecht, C.; Berthelier, J.-J.; Parrot, M.; Lebreton, J.-P.

    2008-01-01

    The DEMETER spacecraft frequently encounters structured plasma and electric field irregularities associated with equatorial spread-F. However, during severe geonagnetic storms, the spacecraft detects broader regions of density structures that extend to higher latitudes, in some instances to the sub-auroral regions. In addition to the electric field irregularities, ELF magnetic field irregularities are sometimes observed. for example, on the walls of the density structures, and appear related to finely-structured spatial currents and/or Alfven waves. The mid-latitude irregularities are compared with those of equatorial spread-F as well as wit11 intense irregularities associated with the trough region observed at sub-auroral latitudes.

  20. A sharp interface immersed boundary method for solving flow with arbitrarily irregular and changing geometry

    CERN Document Server

    Mo, Huangrui; Zhang, Fan; Cronin, Duane S

    2016-01-01

    In this paper, a sharp interface immersed boundary method is developed for efficiently and robustly solving flow with arbitrarily irregular and changing geometries. The proposed method employs a three-step prediction-correction flow reconstruction scheme for boundary treatment and enforces Dirichlet, Neumann, Robin, and Cauchy boundary conditions in a straightforward and consistent manner. Numerical experiments concerning flow of two and three space dimensions, stationary and moving objects, convex and concave geometries, no-slip and slip wall boundary conditions are conducted to demonstrate the proposed method.