Sample records for condilomatosis vulvoperineal gigante

  1. Gigantism

    MedlinePLUS

    ... Other causes include: Carney complex McCune-Albright syndrome (MAS) Multiple endocrine neoplasia type 1 (MEN-1) Neurofibromatosis ... Melmed S, Kleinberg D. Pituitary masses and tumors. In: Melmed S, ... Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Elsevier ...

  2. Evolution of Gigantism in Amphiumid Salamanders

    PubMed Central

    Bonett, Ronald M.; Chippindale, Paul T.; Moler, Paul E.; Van Devender, R. Wayne; Wake, David B.

    2009-01-01

    The Amphiumidae contains three species of elongate, permanently aquatic salamanders with four diminutive limbs that append one, two, or three toes. Two of the species, Amphiuma means and A. tridactylum, are among the largest salamanders in the world, reaching lengths of more than one meter, whereas the third species (A. pholeter), extinct amphiumids, and closely related salamander families are relatively small. Amphiuma means and A. tridactylum are widespread species and live in a wide range of lowland aquatic habitats on the Coastal Plain of the southeastern United States, whereas A. pholeter is restricted to very specialized organic muck habitats and is syntopic with A. means. Here we present analyses of sequences of mitochondrial and nuclear loci from across the distribution of the three taxa to assess lineage diversity, relationships, and relative timing of divergence in amphiumid salamanders. In addition we analyze the evolution of gigantism in the clade. Our analyses indicate three lineages that have diverged since the late Miocene, that correspond to the three currently recognized species, but the two gigantic species are not each other's closest relatives. Given that the most closely related salamander families and fossil amphiumids from the Upper Cretaceous and Paleocene are relatively small, our results suggest at least two extreme changes in body size within the Amphuimidae. Gigantic body size either evolved once as the ancestral condition of modern amphiumas, with a subsequent strong size reduction in A. pholeter, or gigantism independently evolved twice in the modern species, A. means and A. tridactylum. These patterns are concordant with differences in habitat breadth and range size among lineages, and have implications for reproductive isolation and diversification of amphiumid salamanders. PMID:19461997

  3. LTR Retrotransposons Contribute to Genomic Gigantism in Plethodontid Salamanders

    E-print Network

    Castoe, Todd A.

    LTR Retrotransposons Contribute to Genomic Gigantism in Plethodontid Salamanders Cheng Sun1 are found within the salamanders, a clade of amphibians that includes 613 species. Salamander genome sizes as other traits, morphological evolution in salamanders has been profoundly affected by genomic gigantism

  4. Something Old, Something New: El gigante Amapolas

    E-print Network

    Labinger, Andrea G.

    1982-04-01

    SPRING 1982 3 Something Old, Something New: El Gigante Amapolas Andrea G. Labinger The Romantic theatre in Latin America has been largely maligned, or at best, ignored by contemporary criticism. Indeed, there are those who go so far as to deny... passage can be found in Judith and Holoj"ernes (1849) by the Viennese playwright Johann Nestroy, whom Esslin calls a "surrealistic" writer. Holofernes says: "I am na ture's most brilliant piece of work ... I have yet to lose a battle. I am the virgin...

  5. Lightning development associated with two negative gigantic jets

    Microsoft Academic Search

    Gaopeng Lu; Steven A. Cummer; Walter A. Lyons; Paul R. Krehbiel; Jingbo Li; William Rison; Ronald J. Thomas; Harald E. Edens; Mark A. Stanley; William Beasley; Donald R. MacGorman; Oscar A. van der Velde; Morris B. Cohen; Timothy J. Lang; Steven A. Rutledge

    2011-01-01

    Both gigantic jets occurred as part of otherwise normal intracloud flashesThe GJ-producing lightning development implies a depleted upper positive chargeVHF techniques are applicable to detect discharges over the cloud

  6. Late paleozoic fusulinoidean gigantism driven by atmospheric hyperoxia.

    PubMed

    Payne, Jonathan L; Groves, John R; Jost, Adam B; Nguyen, Thienan; Moffitt, Sarah E; Hill, Tessa M; Skotheim, Jan M

    2012-09-01

    Atmospheric hyperoxia, with pO(2) in excess of 30%, has long been hypothesized to account for late Paleozoic (360-250 million years ago) gigantism in numerous higher taxa. However, this hypothesis has not been evaluated statistically because comprehensive size data have not been compiled previously at sufficient temporal resolution to permit quantitative analysis. In this study, we test the hyperoxia-gigantism hypothesis by examining the fossil record of fusulinoidean foraminifers, a dramatic example of protistan gigantism with some individuals exceeding 10 cm in length and exceeding their relatives by six orders of magnitude in biovolume. We assembled and examined comprehensive regional and global, species-level datasets containing 270 and 1823 species, respectively. A statistical model of size evolution forced by atmospheric pO(2) is conclusively favored over alternative models based on random walks or a constant tendency toward size increase. Moreover, the ratios of volume to surface area in the largest fusulinoideans are consistent in magnitude and trend with a mathematical model based on oxygen transport limitation. We further validate the hyperoxia-gigantism model through an examination of modern foraminiferal species living along a measured gradient in oxygen concentration. These findings provide the first quantitative confirmation of a direct connection between Paleozoic gigantism and atmospheric hyperoxia. PMID:22946813

  7. On the Vertical Structuring of Gigantic Jets

    NASA Astrophysics Data System (ADS)

    Da Silva, C.; Pasko, V. P.

    2013-12-01

    Gigantic Jets (GJs) are large-scale electrical discharges between the thundercloud tops and the lower ionosphere. It is estimated that an individual GJ can contribute as much as cloud-to-ground lightning in discharging a thunderstorm system, transferring hundreds of coulombs from thundercloud to the ionosphere [Cummer et al., Nat. Geosci., 2, 617-620, 2009]. GJs are initiated deep inside the thundercloud as intracloud lightning discharges. Owing to a charge imbalance, meaning the upper charge center is depleted with respect to the midlevel charge center, the upward-directed lightning leaders manage to escape through the thundercloud top to form GJs [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008]. As a GJ leader crosses the stratosphere its streamer zone becomes longer and longer, due to the dynamics of streamer growth in a medium with exponentially-decreasing air density, such as in the Earth's atmosphere [Raizer et al., GRL, 33, L23801, 2006]. The speed at which a leader propagates is limited by the air heating of every newly formed leader section, rate of which is slower at upper altitudes in the Earth's atmosphere [da Silva and Pasko, GRL, 39, L13805, 2012]. Despite the expected deceleration of an upward-directed leader, GJs are observed to accelerate as they approach the ionosphere. To address this issue, we propose a simple time-dynamic model for GJ propagation that simulates the upward propagation of a leader discharge accounting for the effects of the expansion of its streamer zone. We propose that the GJ acceleration is a consequence of its vertical structuring and, therefore, can be used to trace the transition altitude between the leader and streamer zone sections of GJs [da Silva and Pasko, GRL, 40, 12, 3315-3319, 2013]. Leaders and streamers are very different electrical discharges in terms of the degree of ionization, temperature, and composition of the plasma inside their channels. A correct description of the vertical structuring of GJs is of fundamental importance for evaluation of their effects in the stratosphere and mesosphere.

  8. Two minimal clones whose join is gigantic Gabor Czedli

    E-print Network

    Czédli, Gábor

    Two minimal clones whose join is gigantic G´abor Cz´edli JATE Bolyai Institute, Szeged, Aradi v´ertan´uk tere 1, HUNGARY­6720. E-mail: czedli@math.u-szeged.hu Key words: clone, minimal clone, majority such that the greatest prime divisor of |A| is at least 5. Then two minimal clones are constructed

  9. A Case of Sotos Syndrome (Cerebral Gigantism) and Psychosis

    Microsoft Academic Search

    Michael T. Compton; Marc Celentana; Brian Price; Andrew C. Furman

    2004-01-01

    Sotos syndrome, or cerebral gigantism, is a syndrome of accelerated growth during early childhood, and a number of craniofacial and other physical abnormalities are commonly present. Behavioral and psychiatric manifestations of the disorder include attention deficits, aggressiveness, and social inhibition. The authors describe a case of psychosis that developed in a patient with Sotos syndrome.

  10. Hereditary Gigantism-the biblical giant Goliath and his brothers

    PubMed Central

    Donnelly, Deirdre E; Morrison, Patrick J

    2014-01-01

    The biblical giant Goliath has an identifiable family tree suggestive of autosomal dominant inheritance. We suggest that he had a hereditary pituitary disorder possibly due to the AIP gene, causing early onset and familial acromegaly or gigantism. We comment on the evidence within the scriptures for his other relatives including a relative with six digits and speculate on possible causes of the six digits. Recognition of a hereditary pituitary disorder in the biblical Goliath and his family sheds additional information on his and other family members battles with David and his relatives. PMID:25075136

  11. Secondary gigantic jets as possible inducers of sprites

    NASA Astrophysics Data System (ADS)

    Lee, Li-Jou; Hsu, Rue-Ron; Su, Han-Tzong; Huang, Sung-Ming; Chou, Jung-Kung; Kuo, Cheng-Ling; Chang, Shu-Chun; Wu, Yen-Jung; Chen, Alfred B.; Frey, Harald U.; Takahashi, Yukihiro; Lee, Lou-Chuang

    2013-04-01

    Three multi-transient luminous events, which were recorded by ISUAL on FORMOSAT-2 and shared a similar generating sequence, are reported. Each event began with a positive cloud-to-ground lightning discharge (CG)-induced sprite, and a secondary gigantic jet (GJ) followed within ~30-50 ms. Then, 1 ms after the GJ, a new sprite occurred near the GJ without associated impulsive lightning signal. The associated electromagnetic signal for one of the events indicates that the GJ is a negative cloud-to-ionosphere discharge carrying a high peak current moment. Cross-analysis of the spectral, image, and electromagnetic data of these three events indicates that the new sprites are likely induced by the secondary GJs, and the high current moment of the secondary GJs appears to be a crucial factor for the induction of the new sprites. Hence, these secondary GJs may have played a role in inducing sprites as much as the negative CGs do for the occurrence of negative sprites.

  12. Controlled Growth of Gigantic Swirls in a Laboratory Magnetosphere

    NASA Astrophysics Data System (ADS)

    Worstell, M. W.; Mauel, M. E.; Roberts, T. M.

    2012-10-01

    Space and laboratory plasma confined by a strong magnetic field have remarkable properties. Low frequency mixing of the plasma occurs through the interchange of long plasma-filled tubes aligned with the magnetic field. The plasma dynamics becomes two-dimensional because these tubes can only move radially or circulate around the poles of the magnetic dipole. Studies of turbulent interchange dynamics made using the Collisionless Terella Experiment (CTX) show that turbulence appears as chaotic time-varying modes with broad global mode structures that interact nonlinearly and form an inverse cascade.footnotetextB.A. Grierson, M.W. Worstell, M.E. Mauel, Phys. Plasmas 16 055902 (2009) When we drive vortex mixing through the application of electrostatic bias to multiple probes, we break the rotational symmetry of the plasma and small vortex tubes are seen to drive larger ``gigantic'' swirls. Statistical analysis of the time-evolving spectra and measurement of the bicoherence of the turbulence show an increase of three wave coupling during non-axisymmetric electrostatic drive of the probe array.

  13. Why might they be giants? Towards an understanding of polar gigantism.

    PubMed

    Moran, Amy L; Woods, H Arthur

    2012-06-15

    Beginning with the earliest expeditions to the poles, over 100 years ago, scientists have compiled an impressive list of polar taxa whose body sizes are unusually large. This phenomenon has become known as 'polar gigantism'. In the intervening years, biologists have proposed a multitude of hypotheses to explain polar gigantism. These hypotheses run the gamut from invoking release from physical and physiological constraints, to systematic changes in developmental trajectories, to community-level outcomes of broader ecological and evolutionary processes. Here we review polar gigantism and emphasize two main problems. The first is to determine the true strength and generality of this pattern: how prevalent is polar gigantism across taxonomic units? Despite many published descriptions of polar giants, we still have a poor grasp of whether these species are unusual outliers or represent more systematic shifts in distributions of body size. Indeed, current data indicate that some groups show gigantism at the poles whereas others show nanism. The second problem is to identify underlying mechanisms or processes that could drive taxa, or even just allow them, to evolve especially large body size. The contenders are diverse and no clear winner has yet emerged. Distinguishing among the contenders will require better sampling of taxa in both temperate and polar waters and sustained efforts by comparative physiologists and evolutionary ecologists in a strongly comparative framework. PMID:22623187

  14. Leader modeling of gigantic jets connecting thunderclouds to the ionosphere Lizhu Tong, Kenichi Nanbu, and Hiroshi Fukunishi 1)

    E-print Network

    Boyer, Edmond

    1 Leader modeling of gigantic jets connecting thunderclouds to the ionosphere Lizhu Tong, Kenichi thunderclouds to the ionosphere. The thundercloud is considered as an electrode igniting gigantic jets and the ionosphere is assumed as the other. The propagation of stepped leader is considered as a field controlled

  15. Gigantism and Acromegaly Due to Xq26 Microduplications and GPR101 Mutation

    PubMed Central

    Trivellin, G.; Daly, A.F.; Faucz, F.R.; Yuan, B.; Rostomyan, L.; Larco, D.O.; Schernthaner-Reiter, M.H.; Szarek, E.; Leal, L.F.; Caberg, J.-H.; Castermans, E.; Villa, C.; Dimopoulos, A.; Chittiboina, P.; Xekouki, P.; Shah, N.; Metzger, D.; Lysy, P.A.; Ferrante, E.; Strebkova, N.; Mazerkina, N.; Zatelli, M.C.; Lodish, M.; Horvath, A.; de Alexandre, R. Bertollo; Manning, A.D.; Levy, I.; Keil, M.F.; de la Luz Sierra, M.; Palmeira, L.; Coppieters, W.; Georges, M.; Naves, L.A.; Jamar, M.; Bours, V.; Wu, T.J.; Choong, C.S.; Bertherat, J.; Chanson, P.; Kamenick, P.; Farrell, W.E.; Barlier, A.; Quezado, M.; Bjelobaba, I.; Stojilkovic, S.S.; Wess, J.; Costanzi, S.; Liu, P.; Lupski, J.R.; Beckers, A.; Stratakis, C.A.

    2015-01-01

    BACKGROUND Increased secretion of growth hormone leads to gigantism in children and acromegaly in adults; the genetic causes of gigantism and acromegaly are poorly understood. METHODS We performed clinical and genetic studies of samples obtained from 43 patients with gigantism and then sequenced an implicated gene in samples from 248 patients with acromegaly. RESULTS We observed microduplication on chromosome Xq26.3 in samples from 13 patients with gigantism; of these samples, 4 were obtained from members of two unrelated kindreds, and 9 were from patients with sporadic cases. All the patients had disease onset during early childhood. Of the patients with gigantism who did not carry an Xq26.3 microduplication, none presented before the age of 5 years. Genomic characterization of the Xq26.3 region suggests that the microduplications are generated during chromosome replication and that they contain four protein-coding genes. Only one of these genes, GPR101, which encodes a G-proteincoupled receptor, was overexpressed in patients pituitary lesions. We identified a recurrent GPR101 mutation (p.E308D) in 11 of 248 patients with acromegaly, with the mutation found mostly in tumors. When the mutation was transfected into rat GH3 cells, it led to increased release of growth hormone and proliferation of growth hormoneproducing cells. CONCLUSIONS We describe a pediatric disorder (which we have termed X-linked acrogigantism [X-LAG]) that is caused by an Xq26.3 genomic duplication and is characterized by early-onset gigantism resulting from an excess of growth hormone. Duplication of GPR101 probably causes X-LAG. We also found a recurrent mutation in GPR101 in some adults with acromegaly. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others.) PMID:25470569

  16. An Evolutionary Cascade Model for Sauropod Dinosaur Gigantism - Overview, Update and Tests

    PubMed Central

    Sander, P. Martin

    2013-01-01

    Sauropod dinosaurs are a group of herbivorous dinosaurs which exceeded all other terrestrial vertebrates in mean and maximal body size. Sauropod dinosaurs were also the most successful and long-lived herbivorous tetrapod clade, but no abiological factors such as global environmental parameters conducive to their gigantism can be identified. These facts justify major efforts by evolutionary biologists and paleontologists to understand sauropods as living animals and to explain their evolutionary success and uniquely gigantic body size. Contributions to this research program have come from many fields and can be synthesized into a biological evolutionary cascade model of sauropod dinosaur gigantism (sauropod gigantism ECM). This review focuses on the sauropod gigantism ECM, providing an updated version based on the contributions to the PLoS ONE sauropod gigantism collection and on other very recent published evidence. The model consist of five separate evolutionary cascades (Reproduction, Feeding, Head and neck, Avian-style lung, and Metabolism). Each cascade starts with observed or inferred basal traits that either may be plesiomorphic or derived at the level of Sauropoda. Each trait confers hypothetical selective advantages which permit the evolution of the next trait. Feedback loops in the ECM consist of selective advantages originating from traits higher in the cascades but affecting lower traits. All cascades end in the trait Very high body mass. Each cascade is linked to at least one other cascade. Important plesiomorphic traits of sauropod dinosaurs that entered the model were ovipary as well as no mastication of food. Important evolutionary innovations (derived traits) were an avian-style respiratory system and an elevated basal metabolic rate. Comparison with other tetrapod lineages identifies factors limiting body size. PMID:24205267

  17. Biology of the sauropod dinosaurs: the evolution of gigantism

    PubMed Central

    Sander, P Martin; Christian, Andreas; Clauss, Marcus; Fechner, Regina; Gee, Carole T; Griebeler, Eva-Maria; Gunga, Hanns-Christian; Hummel, Jrgen; Mallison, Heinrich; Perry, Steven F; Preuschoft, Holger; Rauhut, Oliver W M; Remes, Kristian; Ttken, Thomas; Wings, Oliver; Witzel, Ulrich

    2011-01-01

    The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism. We review the biology of sauropod dinosaurs in detail and posit that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic heritage) and evolutionary innovations at different levels which triggered a remarkable evolutionary cascade. Of these key innovations, the most important probably was the very long neck, the most conspicuous feature of the sauropod bauplan. Compared to other herbivores, the long neck allowed more efficient food uptake than in other large herbivores by covering a much larger feeding envelope and making food accessible that was out of the reach of other herbivores. Sauropods thus must have been able to take up more energy from their environment than other herbivores. The long neck, in turn, could only evolve because of the small head and the extensive pneumatization of the sauropod axial skeleton, lightening the neck. The small head was possible because food was ingested without mastication. Both mastication and a gastric mill would have limited food uptake rate. Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates. The extensive pneumatization of the axial skeleton resulted from the evolution of an avian-style respiratory system, presumably at the base of Saurischia. An avian-style respiratory system would also have lowered the cost of breathing, reduced specific gravity, and may have been important in removing excess body heat. Another crucial innovation inherited from basal dinosaurs was a high BMR. This is required for fueling the high growth rate necessary for a multi-tonne animal to survive to reproductive maturity. The retention of the plesiomorphic oviparous mode of reproduction appears to have been critical as well, allowing much faster population recovery than in megaherbivore mammals. Sauropods produced numerous but small offspring each season while land mammals show a negative correlation of reproductive output to body size. This permitted lower population densities in sauropods than in megaherbivore mammals but larger individuals. Our work on sauropod dinosaurs thus informs us about evolutionary limits to body size in other groups of herbivorous terrestrial tetrapods. Ectothermic reptiles are strongly limited by their low BMR, remaining small. Mammals are limited by their extensive mastication and their vivipary, while ornithsichian dinosaurs were only limited by their extensive mastication, having greater average body sizes than mammals. PMID:21251189

  18. Discovery of the Largest Orbweaving Spider Species: The Evolution of Gigantism in Nephila

    E-print Network

    Coddington, Jonathan A.

    are renowned for being the largest web-spinning spiders, making the largest orb webs, and are model organismsDiscovery of the Largest Orbweaving Spider Species: The Evolution of Gigantism in Nephila Matjaz than 41,000 spider species are known with about 400500 added each year, but for some well-known groups

  19. The Architecture The universe resembles an unfathomably large honeycomb. Gigantic galaxy clusters occupy

    E-print Network

    The Architecture of Space The universe resembles an unfathomably large honeycomb. Gigantic galaxy of galaxies, and in the process, encounters the invisible aspects of space. What the eye doesn't see: The Coma the individual galaxies (gray spots). X-ray scouts like the ROSAT satellite, on the other hand, reveal

  20. Analysis of the first gigantic jet recorded over continental North America

    NASA Astrophysics Data System (ADS)

    van der Velde, Oscar A.; Lyons, Walter A.; Nelson, Thomas E.; Cummer, Steven A.; Li, Jingbo; Bunnell, James

    2007-10-01

    Two low-light cameras near Marfa, Texas, recorded a gigantic jet over northern Mexico on 13 May 2005 at approximately 0423:50 UTC. Assuming that the farthest of two candidate storm systems was its source, the bright lower channel ended in a fork at around 50-59 km height with the very dim upper branches extended to 69-80 km altitude. During the time window containing the jet, extremely low frequency magnetic field recordings show that there was no fast charge moment change larger than 50 coulomb times kilometers (C km) but there was a larger and slower charge moment change of 520 C km over 70 ms. The likely parent thunderstorm was a high-precipitation supercell cluster containing a persistent mesocyclone, with radar echo tops of at least 17 km. However, photogrammetric analysis suggests that the gigantic jet occurred over the forward flank downdraft region with echo tops of 14 km. This part of the supercell may have had an inverted-polarity charge configuration as evidenced by positive cloud-to-ground lightning flashes (+CG) dominating over negative flashes (-CG), while -CGs occurred under the downwind anvil. Four minutes before the gigantic jet, -CG activity practically ceased in this area, while +CG rates increased, culminating during the 20 s leading up to the gigantic jet with four National Lightning Detection Network-detected +CGs. A relative lull in lightning activity of both polarities was observed for up to 1.5 min after the gigantic jet. The maturing storm subsequently produced 30 sprites between 0454 and 0820 UTC, some associated with extremely large impulse charge moment change values.

  1. A gigantic nothosaur (Reptilia: Sauropterygia) from the Middle Triassic of SW China and its implication for the Triassic biotic recovery.

    PubMed

    Liu, Jun; Hu, Shi-Xue; Rieppel, Olivier; Jiang, Da-Yong; Benton, Michael J; Kelley, Neil P; Aitchison, Jonathan C; Zhou, Chang-Yong; Wen, Wen; Huang, Jin-Yuan; Xie, Tao; Lv, Tao

    2014-01-01

    The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent lack of such predators in the eastern Tethyan/western Panthalassic region prior to the Late Triassic. Here we report a gigantic nothosaur from the lower Middle Triassic of Luoping in southwest China (eastern Tethyan ocean), which possesses the largest known lower jaw among Triassic sauropterygians. Phylogenetic analysis suggests parallel evolution of gigantism in Triassic sauropterygians. Discovery of this gigantic apex predator, together with associated diverse marine reptiles and the complex food web, indicates global recovery of shallow marine ecosystems from PTME by the early Middle Triassic. PMID:25429609

  2. A gigantic nothosaur (Reptilia: Sauropterygia) from the Middle Triassic of SW China and its implication for the Triassic biotic recovery

    PubMed Central

    Liu, Jun; Hu, Shi-xue; Rieppel, Olivier; Jiang, Da-yong; Benton, Michael J.; Kelley, Neil P.; Aitchison, Jonathan C.; Zhou, Chang-yong; Wen, Wen; Huang, Jin-yuan; Xie, Tao; Lv, Tao

    2014-01-01

    The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent lack of such predators in the eastern Tethyan/western Panthalassic region prior to the Late Triassic. Here we report a gigantic nothosaur from the lower Middle Triassic of Luoping in southwest China (eastern Tethyan ocean), which possesses the largest known lower jaw among Triassic sauropterygians. Phylogenetic analysis suggests parallel evolution of gigantism in Triassic sauropterygians. Discovery of this gigantic apex predator, together with associated diverse marine reptiles and the complex food web, indicates global recovery of shallow marine ecosystems from PTME by the early Middle Triassic. PMID:25429609

  3. Gigantic lymphangioma with marked extraluminal progression of the ascending colon: report of a case.

    PubMed

    Katsuno, Hidetoshi; Maeda, Koutarou; Hanai, Tsunekazu; Mizuno, Masahiro; Kurashita, Takamitsu; Tsukamoto, Tetsuya

    2015-07-01

    We report a case of gigantic cystic lymphangioma of the ascending colon excised through an open laparotomy. A 34-year-old woman consulted a gynecologist for treatment of infertility. Transvaginal ultrasonography revealed a cystic mass in the pelvis, and she was transferred to our hospital for further investigation. Abdominal enhanced computed tomography (CT) showed a bulky cystic mass, 25cm or larger, in the abdominal and pelvic cavity. Colonoscopy revealed a cystic submucosal tumor with a cushion sign. Cystic lymphangioma was diagnosed and excised via open surgery as we could not exclude its malignant potential. Pathological examination confirmed lymphangioma. To our knowledge, this is the most gigantic lymphangioma of the colon documented in the literature. About 3months after surgery, the patient discovered that she was pregnant and her first baby was delivered at term, uneventfully. PMID:25344823

  4. Cope's Rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates

    PubMed Central

    Lamsdell, James C.; Braddy, Simon J.

    2010-01-01

    Gigantism is widespread among Palaeozoic arthropods, yet causal mechanisms, particularly the role of (abiotic) environmental factors versus (biotic) competition, remain unknown. The eurypterids (Arthropoda: Chelicerata) include the largest arthropods; gigantic predatory pterygotids (Eurypterina) during the Siluro-Devonian and bizarre sweep-feeding hibbertopterids (Stylonurina) from the Carboniferous to end-Permian. Analysis of family-level originations and extinctions among eurypterids and Palaeozoic vertebrates show that the diversity of Eurypterina waned during the Devonian, while the Placodermi radiated, yet Stylonurina remained relatively unaffected; adopting a sweep-feeding strategy they maintained their large body size by avoiding competition, and persisted throughout the Late Palaeozoic while the predatory nektonic Eurypterina (including the giant pterygotids) declined during the Devonian, possibly out-competed by other predators including jawed vertebrates. PMID:19828493

  5. The evolution of island gigantism and body size variation in tortoises and turtles.

    PubMed

    Jaffe, Alexander L; Slater, Graham J; Alfaro, Michael E

    2011-08-23

    Extant chelonians (turtles and tortoises) span almost four orders of magnitude of body size, including the startling examples of gigantism seen in the tortoises of the Galapagos and Seychelles islands. However, the evolutionary determinants of size diversity in chelonians are poorly understood. We present a comparative analysis of body size evolution in turtles and tortoises within a phylogenetic framework. Our results reveal a pronounced relationship between habitat and optimal body size in chelonians. We found strong evidence for separate, larger optimal body sizes for sea turtles and island tortoises, the latter showing support for the rule of island gigantism in non-mammalian amniotes. Optimal sizes for freshwater and mainland terrestrial turtles are similar and smaller, although the range of body size variation in these forms is qualitatively greater. The greater number of potential niches in freshwater and terrestrial environments may mean that body size relationships are more complicated in these habitats. PMID:21270022

  6. Analysis of the first gigantic jet recorded over continental North America

    Microsoft Academic Search

    Oscar A. van der Velde; Walter A. Lyons; Thomas E. Nelson; Steven A. Cummer; Jingbo Li; James Bunnell

    2007-01-01

    Two low-light cameras near Marfa, TX recorded a gigantic jet over northern Mexico on 13 May 2005 at approximately 0423:50 UTC. Assuming the farthest of two candidate storm systems, the bright lower channel ended in a fork at around 50-59 km height with the very dim upper branches extended to 69-80 km altitude. During the time window containing the jet,

  7. Analysis of the first gigantic jet recorded over continental North America

    Microsoft Academic Search

    Oscar A. van der Velde; Walter A. Lyons; Thomas E. Nelson; Steven A. Cummer; Jingbo Li; James Bunnell

    2007-01-01

    Two low-light cameras near Marfa, Texas, recorded a gigantic jet over northern Mexico on 13 May 2005 at approximately 0423:50 UTC. Assuming that the farthest of two candidate storm systems was its source, the bright lower channel ended in a fork at around 5059 km height with the very dim upper branches extended to 6980 km altitude. During the time

  8. Velocidades radiales de estrellas gigantes rojas y blue stragglers en cmulos abiertos

    NASA Astrophysics Data System (ADS)

    Gonzlez, J. F.; Lapasset, E.

    Se presentan mediciones de las estrellas ms brillantes en los campos de los cmulos abiertos NGC 6530, NGC 2516, NGC 3114, Cr 223 y NGC 2437. Mediante correlaciones cruzadas se obtiene la velocidad de unas 25 gigantes rojas con el objeto de derivar la velocidad media de cada asociacin. En base a los espectros obtenidos de los blue stragglers se discuten sus principales caractersticas y su probabilidad de pertenencia. Finalmente, se presentan las observaciones para cinco nuevas binarias espectroscpicas detectadas.

  9. The triangulation of the gigantic jets observed by the optical observation network in Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Alfred B.; Huang, Chien-Fong; Peng, Kang-Ming; Su, Han-Tzong; Hsu, Rue-Ron

    2015-04-01

    The optical triangulation of sprites and elves by the multiple sites has been done in the past decades, but the similar observation on gigantic jets has never been reported yet. A ground optical observation network consisting of four stations at Kimen, Penghu, Tainan, and Taitung (from west to east) has been established in Taiwan since 2012. Each station equipped with two sets of Watec low-light sensitivity cameras, and the elevation and azimuth of the observation can be fully remote controlled to point toward the on-going convection system in the vicinity of Taiwan. In summer 2014, more than 6 gigantic jets were captured by at least two stations successfully. The triangulation and ULF sferics of these interesting events provides an excellent chance to explore the spatial and temporal evolution of the jets in different phases. In this presentation, this ground observation network will be introduced, the detail evolution of the recorded gigantic jets is presented. The preliminary result implies that the jets may not pop from the cloudtop straightforwardly, and some twists occur during the propagation of the jets. A more complicated analysis of the tomography for the advanced triangulation will be mentioned, too.

  10. Birmingham Mid-Head Resection hip arthroplasty in a young man with gigantism.

    PubMed

    Murphy, Michael T; Shillington, Mark P; Mogridge, Damon R; Journeaux, Simon F

    2012-02-01

    The Birmingham Mid-Head Resection (Smith & Nephew Ltd, Warwick, United Kingdom) arthroplasty is a new bone-conserving procedure that, like hip resurfacing, is used in younger, active patients. We present the case of a young man with Sotos syndrome (cerebral gigantism) with associated extraordinary stature (height, 2.16 m; weight, 157 kg) who underwent Birmingham Mid-Head Resection arthroplasty. The large stature of this patient required a custom manufactured prosthesis (a femoral head 68 mm in diameter with an acetabular cup 76 mm in diameter). We believe this to be the largest metal-on-metal resurfacing articulation and hip arthroplasty reported to date. PMID:21704481

  11. GaAs-oxide interface states - Gigantic photoionization via Auger-like process

    NASA Technical Reports Server (NTRS)

    Lagowski, J.; Kazior, T. E.; Gatos, H. C.; Walukiewicz, W.; Siejka, J.

    1981-01-01

    Spectral and transient responses of photostimulated current in MOS structures were employed for the study of GaAs-anodic oxide interface states. Discrete deep traps at 0.7 and 0.85 eV below the conduction band were found with concentrations of 5 x 10 to the 12th/sq cm and 7 x 10 to the 11th/sq cm, respectively. These traps coincide with interface states induced on clean GaAs surfaces by oxygen and/or metal adatoms (submonolayer coverage). In contrast to surfaces with low oxygen coverage, the GaAs-thick oxide interfaces exhibited a high density (about 10 to the 14th/sq cm) of shallow donors and acceptors. Photoexcitation of these donor-acceptor pairs led to a gigantic photoionization of deep interface states with rates 1000 times greater than direct transitions into the conduction band. The gigantic photoionization is explained on the basis of energy transfer from excited donor-acceptor pairs to deep states.

  12. Gigantic optical magneto-electric effect in CuB2O4

    NASA Astrophysics Data System (ADS)

    Saito, Mitsuru; Taniguchi, Kouji; Arima, Takahisa

    2008-03-01

    It has been recognized since 1960s that magneto-electric (ME) materials may also show an optical magneto-electric (OME) effect showing up as a change in optical absorption with reversal of the propagating direction of light. The OME effect is an interesting object of scientific research and provides possibilities for applications. However, the changes in absorption coefficient ever discovered were very small (less than 0.2 %). We present a gigantic OME effect in a noncentrosymmetric weak ferromagnet CuB2O4, in which the absorption coefficient changes by a factor of three with reversal of a very weak magnetic field of 300 Oe. This magnitude of OME effect enables us to observe it by a CCD camera with linearly polarized near-infrared and visible light. Spectroscopic study and comparison of OME effect with magnetization indicate an important role of canted antiferromagnetic spin ordering and local symmetry of a square Cu^2+ site. The gigantic OME effect can be applicable to optical devices like magnetic switching of color in the future.

  13. Web gigantism in Darwin's bark spider, a new species from Madagascar (Araneidae: Caerostris) Matjaz Kuntner1,2

    E-print Network

    Agnarsson, Ingi

    Web gigantism in Darwin's bark spider, a new species from Madagascar (Araneidae: Caerostris) Matjaz, is grossly underestimated. Most species build large webs at forest edges, clearings, and gardens niche: casting its web across streams, rivers and lakes, so that the orb is suspended above water

  14. ecCNO solar neutrinos: A challenge for gigantic ultra-pure liquid scintillator detectors

    NASA Astrophysics Data System (ADS)

    Villante, F. L.

    2015-03-01

    Neutrinos produced in the Sun by electron capture reactions on 13N, 15O and 17F, to which we refer as ecCNO neutrinos, are not usually considered in solar neutrino analysis since the expected fluxes are extremely low. The experimental determination of this sub-dominant component of the solar neutrino flux is very difficult but could be rewarding since it provides a determination of the metallic content of the solar core and, moreover, probes the solar neutrino survival probability in the transition region at E? ? 2.5 MeV. In this Letter, we suggest that this difficult measure could be at reach for future gigantic ultra-pure liquid scintillator detectors, such as LENA.

  15. Gate-tunable gigantic lattice deformation in VO{sub 2}

    SciTech Connect

    Okuyama, D., E-mail: okuyama@riken.jp, E-mail: nakano@imr.tohoku.ac.jp, E-mail: iwasa@ap.t.u-tokyo.ac.jp; Hatano, T. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Nakano, M., E-mail: okuyama@riken.jp, E-mail: nakano@imr.tohoku.ac.jp, E-mail: iwasa@ap.t.u-tokyo.ac.jp [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Takeshita, S.; Ohsumi, H.; Tardif, S. [RIKEN SPring-8 Center, Hyogo 679-5148 (Japan); Shibuya, K. [National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8562 (Japan); Yumoto, H.; Koyama, T.; Ohashi, H. [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Takata, M. [RIKEN SPring-8 Center, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Kawasaki, M.; Tokura, Y.; Iwasa, Y., E-mail: okuyama@riken.jp, E-mail: nakano@imr.tohoku.ac.jp, E-mail: iwasa@ap.t.u-tokyo.ac.jp [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo, Tokyo 113-8656 (Japan); Arima, T. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); RIKEN SPring-8 Center, Hyogo 679-5148 (Japan); Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561 (Japan)

    2014-01-13

    We examined the impact of electric field on crystal lattice of vanadium dioxide (VO{sub 2}) in a field-effect transistor geometry by in-situ synchrotron x-ray diffraction measurements. Whereas the c-axis lattice parameter of VO{sub 2} decreases through the thermally induced insulator-to-metal phase transition, the gate-induced metallization was found to result in a significant increase of the c-axis length by almost 1% from that of the thermally stabilized insulating state. We also found that this gate-induced gigantic lattice deformation occurs even at the thermally stabilized metallic state, enabling dynamic control of c-axis lattice parameter by more than 1% at room temperature.

  16. A gigantic, exceptionally complete titanosaurian sauropod dinosaur from southern Patagonia, Argentina.

    PubMed

    Lacovara, Kenneth J; Lamanna, Matthew C; Ibiricu, Lucio M; Poole, Jason C; Schroeter, Elena R; Ullmann, Paul V; Voegele, Kristyn K; Boles, Zachary M; Carter, Aja M; Fowler, Emma K; Egerton, Victoria M; Moyer, Alison E; Coughenour, Christopher L; Schein, Jason P; Harris, Jerald D; Martnez, Rubn D; Novas, Fernando E

    2014-01-01

    Titanosaurian sauropod dinosaurs were the most diverse and abundant large-bodied herbivores in the southern continents during the final 30 million years of the Mesozoic Era. Several titanosaur species are regarded as the most massive land-living animals yet discovered; nevertheless, nearly all of these giant titanosaurs are known only from very incomplete fossils, hindering a detailed understanding of their anatomy. Here we describe a new and gigantic titanosaur, Dreadnoughtus schrani, from Upper Cretaceous sediments in southern Patagonia, Argentina. Represented by approximately 70% of the postcranial skeleton, plus craniodental remains, Dreadnoughtus is the most complete giant titanosaur yet discovered, and provides new insight into the morphology and evolutionary history of these colossal animals. Furthermore, despite its estimated mass of about 59.3 metric tons, the bone histology of the Dreadnoughtus type specimen reveals that this individual was still growing at the time of death. PMID:25186586

  17. Molecular design of TiO2 for gigantic red shift via sublattice substitution.

    PubMed

    Shao, Guosheng; Deng, Quanrong; Wan, Lin; Guo, Meilan; Xia, Xiaohong; Gao, Yun

    2010-11-01

    The effects of 3d transition metal doping in TiO2 phases have been simulated in detail. The results of modelling indicate that Mn has the biggest potential among 3d transition metals, for the reduction of energy gap and the introduction of effective intermediate bands to allow multi-band optical absorption. On the basis of theoretical formulation, we have incorporated considerable amount of Mn in nano-crystalline TiO2 materials. Mn doped samples demonstrate significant red shift in the optical absorption edge, with a secondary absorption edge corresponding to theoretically predicted intermediate bands/states. The gigantic red shift achievable in Mn-doped TiO2 is expected to extend the useful TiO2 functionalities well beyond the UV threshold via the optical absorption of both visible and infrared photon irradiance. PMID:21137872

  18. Intraspecific competition and high food availability are associated with insular gigantism in a lizard

    NASA Astrophysics Data System (ADS)

    Pafilis, Panayiotis; Meiri, Shai; Foufopoulos, Johannes; Valakos, Efstratios

    2009-09-01

    Resource availability, competition, and predation commonly drive body size evolution. We assess the impact of high food availability and the consequent increased intraspecific competition, as expressed by tail injuries and cannibalism, on body size in Skyros wall lizards ( Podarcis gaigeae). Lizard populations on islets surrounding Skyros (Aegean Sea) all have fewer predators and competitors than on Skyros but differ in the numbers of nesting seabirds. We predicted the following: (1) the presence of breeding seabirds (providing nutrients) will increase lizard population densities; (2) dense lizard populations will experience stronger intraspecific competition; and (3) such aggression, will be associated with larger average body size. We found a positive correlation between seabird and lizard densities. Cannibalism and tail injuries were considerably higher in dense populations. Increases in cannibalism and tail loss were associated with large body sizes. Adult cannibalism on juveniles may select for rapid growth, fuelled by high food abundance, setting thus the stage for the evolution of gigantism.

  19. The Early ULF Signal of the Gigantic Jets Revealed By Hilbert-Huang Transform

    NASA Astrophysics Data System (ADS)

    Huang, Po-Hsun; Bing-Chih Chen, Alfred

    2015-04-01

    The conventional Fourier analysis on the sferics in ULF and VLF bandpasses has been done for years. Several phenomena e.g. whistler and Schumann resonance have been well studied by the Fourier spectrum comprehensively. But the Fourier analysis is computed by an integration over time, therefore, the temporal resolution is smoothed, and limited not only by the sampling rate but also the size of the integration window. The instantaneous frequency can't be obtained through this conventional approach. We introduce the Hilbert-Huang transform (HHT) instead of Fourier transform to analyze the sferics of TLEs recorded at Lulin observatory. The Hilbert-Huang transform decomposes a signal into so-called intrinsic mode functions (IMF), and derive instantaneous frequency data by differentiating the phase angle yielded by Hilbert transform. Our analysis of HHT on several gigantic jets recorded by ground observation surprisingly revealed an early signal of frequency-change during the phase of the leading jet, and this early signal can not be identified by Fourier analysis. In the phase of leading jet, the amplitude of the sferics remains a constant and no significant features are recognized in the recorded waveform, but an obvious frequency change about 100-200 millisecond prior to the main discharge of the full development jets (FDJs), which can be clearly recognized in the HHT spectra of all observed gigantic jets. From a further simulation, this frequency change is confirmed to come from the nature of the discharge, not an alias or a false signal generated by the analysis method. This early signal may implies an in-cloud discharge process which is suggested by Krehbiel et al. [2008

  20. A Gray-purple Mass on the Floor of the Mouth: Gigantic Mucogingival Pyogenic Granuloma in a Teenage Patient

    PubMed Central

    Brunet-LLobet, Llus; Miranda-Rius, Jaume; Lahor-Soler, Eduard; Mrina, Ombeni; Nadal, Alfons

    2014-01-01

    Pyogenic granuloma is defined as a benign neoplasm of vascular phenotype. This case describes the clinical and histopathological features of a gigantic mucogingival pyogenic granuloma, in a 14-year-old healthy black boy. This exophytic gray-purple mass, related to a toothpick injury, had more than twelve-month evolution on the anterior mandible involving lingual area besides to the floor of the mouth pressing the right salivary duct. Conservative excision was performed, followed by uncomplicated healing with no recurrence in two years. The histopathological examination reported a pyogenic granuloma (lobular capillary haemangioma). The authors provide a discussion of the presurgical differential diagnosis of the lesion. This case report presents an extremely uncommon location of a gigantic pyogenic granuloma, involving mucogingival complex and affecting the salivary outflow. This clinical manuscript may shed light on the controversies about possible mechanisms inducing oral pyogenic granuloma. PMID:24987485

  1. Floristic composition of the cerrado in the P-de-Gigante Reserve (Santa Rita do Passa Quatro, southeastern Brazil)

    Microsoft Academic Search

    Marco Antnio Batalha; Waldir Mantovani

    2001-01-01

    ABSTRACT - (Floristic composition,of the,cerrado in the,P-de-Gigante Reserve (Santa Rita do Passa Quatro, southeastern Brazil)). We studied a 1225 ha area, composed mainly of cerrado, in Santa Rita do Passa Quatro, So Paulo State, southeastern Brazil (21?36-38S, 47?36-39W). In three cerrado physiognomies (campo cerrado ? a wooded savanna, cerrado sensu stricto ? a

  2. Gigantic transverse voltage induced via off-diagonal thermoelectric effect in CaxCoO2 thin films

    Microsoft Academic Search

    Kouhei Takahashi; Tsutomu Kanno; Akihiro Sakai; Hideaki Adachi; Yuka Yamada

    2010-01-01

    Gigantic transverse voltages exceeding several tens volt have been observed in CaxCoO2 thin films with tilted c-axis orientation upon illumination of nanosecond laser pulses. The voltage signals were highly anisotropic within the film surface showing close relation with the c-axis tilt direction. The magnitude and the decay time of the voltage strongly depended on the film thickness. These results confirm

  3. Peculiarities of the geologic structure of gigantic gas fields of the western Siberian oil and gas province

    SciTech Connect

    Belyi, N.

    1991-03-01

    The Western Siberian Oil and Gas Province is a unique one regarding the concentration of natural gas resources in Mesozoic terrigenous formations. Discovery of gigantic natural gas fields makes it possible to provide high level of gas production for future prospects. The USSR has enormous potential possibilities for discoveries of new natural gas fields onshore, as well as offshore. At present, three gigantic gas fields have been developed, namely Medvezhie, Urongoi, and Yamburg. The first one has been in operation for 18 years. In the Mesozoic section, three productive complexes can be noticed: Upper Cretaceous, Lower Cretaceous, and Jurassic. The Upper Cretaceous production complex is mostly explored, with unique gas resources containing mainly methane having been discovered. The Lower Cretaceous production complex is characterized by considerable lithofaceous uniformity of reservoirs. Gas pools of this complex contain considerable quantities of condensate quite often having oil rims. The Jurassic production complex, which is characterized by its complicated structure and considerable changeability of the filtration properties, is less studied. Study of the geological structural peculiarities of the gigantic gas fields of Western Siberia gives us the possibility to find new approval for the development and exploration of gas fields.

  4. Gigantic jet observation by the ISUAL payload of FORMOSAT-2 satellite

    NASA Astrophysics Data System (ADS)

    Hsu, R.; Chen, A. B.; Kuo, C.; Lee, Y.; Su, H.; Fukunishi, H.; Takahashi, Y.; Adachi, T.; Yamamoto, K.; Frey, H. U.; Mende, S. B.; Lee, L.

    2005-12-01

    Gigantic jet is a kind of transient luminous events (TLEs), which was first discovered in 2002 [Su et al]. Based on the 16ms time resolution black/white images, three luminous stages, called leading jet, fully-developed jet, and trailing jet, were identified. At the fully-developed stage, the fully-extended luminous body connected the cloud top at 15km with the E-layer ionosphere at 90km. The leading jet, which can be viewed as the pre-stage of the fully- developed jet, behaved like a stepped leader of cloud-to-ground (CG) lightning. The trailing jets have similar dynamical evolution features as the blue jets, where a funnel-shape jet emerged from the cloud-top and propagating upward. The luminous period of these jets lasted from 300 ms to 500 ms, which is longer than typical sprites but is shorter than that of the large blue jets observed by Pasko et al (2002). From the associated ELF emissions, the charge moment changes of GJs were estimated to be 1000-2000C-km and the polarity was determined to be negative. Both optical and radio signals suggested that GJs were not CG-induced events, and likely are true discharges from thundercloud to the ionosphere. Among the TLE events recorded by the ISUAL payload on the FORMOSAT-2 satellite, a gigantic jet event was identified. The spectrophotometric data recorded by the ISUAL SP reveals that the GJ is more energetic than sprites. The expected spatial-temporal properties of GJ were confirmed by the ISUAL array photometer. The ISUAL AP data indicates that the electric field intensity of GJ is much larger than the sprite QE field intensity above 70 km. Both ISUAL imager and AP data demonstrate that the fully-developed stage in GJ truly is an upward discharge from the cloud-top to ionosphere and plays the similar role as the return stroke in cloud-to-ground lightning. In this paper, the ISUAL data on this fantastic event will be presented, including its spectroscopic data and dynamical properties at 1ms time resolution. The corresponding ELF signals, observed by Onagawa station in Japan and Esrange station in Sweden, will also be shown.

  5. Discovery of gigantic molecular nanostructures using a flow reaction array as a search engine

    PubMed Central

    Zang, Hong-Ying; de la Oliva, Andreu Ruiz; Miras, Haralampos N.; Long, De-Liang; McBurney, Roy T.; Cronin, Leroy

    2014-01-01

    The discovery of gigantic molecular nanostructures like coordination and polyoxometalate clusters is extremely time-consuming since a vast combinatorial space needs to be searched, and even a systematic and exhaustive exploration of the available synthetic parameters relies on a great deal of serendipity. Here we present a synthetic methodology that combines a flow reaction array and algorithmic control to give a chemical real-space search engine leading to the discovery and isolation of a range of new molecular nanoclusters based on [Mo2O2S2]2+-based building blocks with either fourfold (C4) or fivefold (C5) symmetry templates and linkers. This engine leads us to isolate six new nanoscale cluster compounds: 1, {Mo10(C5)}; 2, {Mo14(C4)4(C5)2}; 3, {Mo60(C4)10}; 4, {Mo48(C4)6}; 5, {Mo34(C4)4}; 6, {Mo18(C4)9}; in only 200 automated experiments from a parameter space spanning ~5 million possible combinations. PMID:24770632

  6. Endochondral gigantism: a newly recognized skeletal dysplasia with pre- and postnatal overgrowth and endocrine abnormalities.

    PubMed

    Schmidt, Heinrich; Kammer, Birgit; Grasser, Monika; Enders, Angelika; Rost, Imma; Kiess, Wieland

    2007-08-15

    We report on a 3-year-old male, born at 34 weeks of gestation, with marked pre- and postnatal overgrowth, birth weight of 6,600 g, length of 61 cm, and head circumference of 38.5 cm. A striking phenotype was recorded at birth, which became more evident during the follow-up period. He had macrobrachycephaly, facial abnormalities, small thoracic cage, long trunk, deformed spine, rhizomelia, large hands and feets, absent subcutaneous fat, small umbilical hernia, inguinal hernias, and large joints with mild contractures. Hypoglycemic episodes and obstructive apnea complicated the neonatal period. During follow-up, overgrowth continued with a height of 146 cm (+11.65 SDS) and a weight of 39 kg (BMI 18.3 kg/m(2)) at 3.5 years. Endocrinological work-up disclosed extremely low levels of growth hormone, insulin-like growth factors, and insulin. What makes our patient unique is the association of marked prenatal overgrowth; unusual phenotype; skeletal dysplasia caused by accelerated endochondral ossification resulting in cartilage hyperplasia of the skull base and spine, and postnatal gigantism; and complete absence of subcutaneous fat. Other well-known overgrowth syndromes were excluded. We hypothesize that autocrine/paracrine growth factors could be the cause of excessive endochondral ossification. Alternately, activating mutations in transcription factors involved in both growth and endocrine/metabolic homeostasis could be responsible for this unusual phenotype. PMID:17618504

  7. A new technique for reconstruction of the current moment waveform related to a gigantic jet from the magnetic field component recorded by an ELF station

    NASA Astrophysics Data System (ADS)

    Ku?Ak, Andrzej; M?Ynarczyk, Janusz

    2011-04-01

    The paper presents a reconstruction of the current moment waveform of the gigantic jet observed optically last winter in Europe, based on the magnetic field component of the ELF electromagnetic field, recorded by the Hylaty station in Poland. Gigantic jets have only been observed so far on a few occasions, and there is still relatively little known about them. In order to analyze the recorded signal we have developed a new technique, which makes it possible to obtain the actual current moment waveform of the lightning discharges associated with the gigantic jet by eliminating from the waveform the effects of both the impulse response of the receiver and the Earth-ionosphere propagation channel. The proposed method can be also used to analyze other waveform observations, especially in the ELF and VLF frequency bands.

  8. New color images of sprites, halos and gigantic jets from the International Space Station

    NASA Astrophysics Data System (ADS)

    Yair, Y.; Rubanenko, L.; Mezuman, K.; Elhalel, G.; Pariente, M.; Glickman-Pariente, M.; Ziv, B.; Takahashi, Y.; Inoue, T.

    2012-12-01

    During July-August 2011, Expedition 28/29 JAXA astronaut Satoshi Furukawa conducted TLE observations from the International Space Station in conjunction with the "Cosmic Shore" program produced by NHK. An EMCCD normal video-rate color TV camera was used to conduct directed observations from the Earth-pointing Copula module. The target selection was based on the methodology developed for the MEIDEX sprite campaign on board the space shuttle Columbia in January 2003 (Ziv et al., 2004). We used the Aviation Weather Center (http://aviationweather.gov) daily significant weather forecast maps (SIGWX) to select regions with high probability for convective activity and thunderstorm such that they were within the camera FOV as deduced from the ISS trajectory and distance to the limb (2240 km). For increasing the chance for successful observations, only storms with predicted "Frequent Cb" and cloud tops above 45 Kft (~14 km) were selected. Additionally, we targeted tropical storms and hurricanes over the oceans. The observation geometry was pre-determined and uploaded daily to the ISS with pointing options to limb, oblique or nadir, based on the predicted location of the storm with regards to the ISS. The pointing angle was rotated in real-time according to visual eyesight by the astronaut. We present results of 10 confirmed TLEs: 8 sprites, 1 sprite halo and 1 gigantic jet, out of <2 hours of video. Sprites tend to appear in a single frame simultaneously with maximum lightning brightness. Unique images (a) from nadir of a sprite horizontally displaced form the lightning light and (b) from oblique view of a sprite halo, enable the calculation of dimensions and volumes occupied by these TLEs. Since time stamping on the ISS images was accurate within 1 s, matching with ELF and WWLLN data for the parent lightning location is limited. Nevertheless, the results prove that the ISS is an ideal platform for lightning and TLE observations, and careful operational procedures greatly enhance the value of observation time.;

  9. Gigantic jets produced by an isolated tropical thunderstorm near Runion Island

    NASA Astrophysics Data System (ADS)

    Soula, Serge; van der Velde, Oscar; Montanya, Joan; Huet, Patrice; Barthe, Christelle; Br, Jzsef

    2011-10-01

    Five gigantic jets (GJs) have been recorded with video and photograph cameras on 7 March 2010 above an isolated tropical storm east of Runion Island. Three of them were produced before the storm reached its coldest cloud top temperature (approximately -81C), and two others occurred during the cloud extension. Thanks to the close distance of observation (50 km), the luminosity within the cloud was recorded, and the events are analyzed in unprecedented detail. The tops of the GJs are estimated between 80 and 90 km. All these GJs are accompanied by long, continuous cloud illumination, and they are preceded and followed by intermittent optical flashes from the cloud, most of time without any cloud-to-ground (CG) flash simultaneously detected, which suggests they originated mainly as intracloud discharges and without any charge transfer to Earth. The CG lightning activity is observed to cease a few tens of seconds before the jets. According to ELF data recorded at Nagycenk, Hungary, the five GJs serve to raise negative charge. Their duration ranges from 333 to 850 ms. The leading jet has the most variable duration (33-167 ms) and propagates faster at higher altitudes. The trailing jet exhibits a continuous decrease of luminosity in different parts of the jet (lower channel, transition zone and, for most events, carrot sprite-like top) and in the cloud, with possible rebrightening. The lower channels (20-40 km altitude) produce blue luminosity which decreases with altitude and become more and more diffuse with time. The transition zone (around 40-65 km) consists of bright red, luminous beads slowly going up (104 m s-1), retracing the initial leading jet channels.

  10. Transsphenoidal surgery for pituitary gigantism and galactorrhea in a 3.5 year old child.

    PubMed

    Flitsch, J; Ldecke, D K; Stahnke, N; Wiebel, J; Saeger, W

    2000-05-01

    The management of pituitary macroadenomas which lead to gigantism may require multiple therapeutical approaches, including medical treatment, surgery, and radiation therapy. Transsphenoidal surgery (TSS) during early childhood that achieves total removal of a growth hormone (GH) secreting tumor is rarely reported. The surgeon is confronted with special problems regarding the infantile anatomy. In this case, a 3.5 year old child, the youngest successfully treated by TSS so far, suffered from a GH- and prolactin (PRL) secreting macroadenoma of the pituitary gland. The girl initially presented with an increasing growth rate, later with breast development, and finally, at the age of 2.8 years, with galactorrhea and secretion of blood from the nipples. Increased levels of GH [122 micrograms/l], insulin-like growth factor (IGF-1) [830 micrograms/l], insulin-like growth factor binding protein 3 (IGFBP-3) [8.6 mg/l] and PRL [590 micrograms/l] were found. MRI scans revealed a macroadenoma of 2.7 cm diameter. An eight-week trial of relatively low dose dopamine agonists led to a reduction of PRL, while the GH- and IGF-1 levels remained unchanged; the tumor showed only little shrinkage. Since there was chiasma compression, we opted for early TSS. A complete tumor removal was achieved despite the difficulties of a narrow approach. After TSS, low levels of GH, IGF-1, and PRL documented a complete tumor removal, but persistent diabetes insipidus and anterior lobe deficits resulted from surgery. In summary, if primary medical therapy alone is unable to adequately reduce hormone hypersecretion and tumor size in early childhood, TSS is recommended. Thus, radiation therapy may be reserved for surgical failure. PMID:11081147

  11. Gigantic landslides versus glacial deposits: on origin of large hummock deposits in Alai Valley, Northern Pamir

    NASA Astrophysics Data System (ADS)

    Reznichenko, Natalya

    2015-04-01

    As glaciers are sensitive to local climate, their moraines position and ages are used to infer past climates and glacier dynamics. These chronologies are only valid if all dated moraines are formed as the result of climatically driven advance and subsequent retreat. Hence, any accurate palaeoenvironmental reconstruction requires thorough identification of the landform genesis by complex approach including geomorphological, sedimentological and structural landform investigation. Here are presented the implication of such approach for the reconstruction of the mega-hummocky deposits formation both of glacial and landslide origin in the glaciated Alai Valley of the Northern Pamir with further discussion on these and similar deposits validity for palaeoclimatic reconstructions. The Tibetan Plateau valleys are the largest glaciated regions beyond the ice sheets with high potential to provide the best geological record of glacial chronologies and, however, with higher probabilities of the numerous rock avalanche deposits including those that were initially considered of glacial origin (Hewitt, 1999). The Alai Valley is the largest intermountain depression in the upper reaches of the Amudarja River basin that has captured numerous unidentified extensive hummocky deposits descending from the Zaalai Range of Northern Pamir, covering area in more than 800 km2. Such vast hummocky deposits are usually could be formed either: 1) glacially by rapid glacial retreat due to the climate signal or triggered a-climatically glacial changes, such as glacial surge or landslide impact, or 2) during the landslide emplacement. Combination of sediment tests on agglomerates forming only in rock avalanche material (Reznichenko et al., 2012) and detailed geomorphological and sedimentological descriptions of these deposits allowed reconstructing the glacial deposition in the Koman and Lenin glacial catchments with identification of two gigantic rock avalanches and their relation to this glacial deposits. Here are presented a new data on: parameters, extent and probable source for Lenin rock avalanche, travelled 24 km from the back wall of the Lenin Glacier over the glacial Achiktash hummock deposit covering more than 35 km2; updated data on Koman rock avalanche deposit, such as its extend and source; the first reconstruction of the Achiktash glacial material deposition with proposed landscape evolution during recent Quaternary in respect to the large landslide in the catchment. Hewitt, K., 1999. Quaternary moraines vs. catastrophic rock avalanches in the Karakoram Himalaya, Northern Pakistan. Quaternary Research, v. 51, p. 220-237. Reznichenko, N.V., Davies, T.R.H., Shulmeister, J. and Larsen S.H, 2012. A new technique for identifying rock-avalanche-sourced sediment in moraines and some paleoclimatic implications. Geology, v. 40, p. 319-322.

  12. Optical emissions and behaviors of the blue starters, blue jets, and gigantic jets observed in the Taiwan transient luminous event ground campaign

    NASA Astrophysics Data System (ADS)

    Chou, J. K.; Tsai, L. Y.; Kuo, C. L.; Lee, Y. J.; Chen, C. M.; Chen, A. B.; Su, H. T.; Hsu, R. R.; Chang, P. L.; Lee, L. C.

    2011-07-01

    On 22 July 2007, 37 blue jets/starters and 1 gigantic jet occurring over a thunderstorm in the Fujian province of China were observed from the Lulin observatory on the central mountain ridge of Taiwan. The majority of the jets were observed to occur in a 5 min window during the mature phase of the jet-producing thunderstorm. These jets have significant red band emissions. However, the blue emissions from these jets were not discernible due to severe atmospheric scattering. A model estimation of the emissions from a streamer reveals that the red emissions in blue starters and blue jets are mainly from the nitrogen first positive band (1PN2). The type II gigantic jet is the first of this type that was observed from the ground. The generation sequence of the gigantic jet begins with a blue starter, then a blue jet occurs at the same cloud top after 100 ms and finally develops into a gigantic jet 50 ms later. Using optical strokes as surrogates of the lightning strokes, the correlations between jets and the cloud lightning are explored. The results indicate that the occurrence of jets can be affected by the preceding local cloud-to-ground (CG) lightning or nearby lightning (intracloud (IC) or CG), while in turn the jets might also affect the ensuing lightning activity.

  13. Gigantic terahertz magnetochromism via electromagnons in the hexaferrite magnet Ba2Mg2Fe12O22

    NASA Astrophysics Data System (ADS)

    Kida, N.; Kumakura, S.; Ishiwata, S.; Taguchi, Y.; Tokura, Y.

    2011-02-01

    Effects of temperature (6-225 K) and magnetic field (0-7 T) on the low-energy (1.2-5 meV) electrodynamics of the electromagnon, the magnetic resonance driven by the light electric field, have been investigated for a hexaferrite magnet Ba2Mg2Fe12O22 by using terahertz time-domain spectroscopy. We find the gigantic terahertz magnetochromism via electromagnons; the magnetochromic change, as defined by the difference of the absorption intensity with and without magnetic field, exceeds 500% even at 0.6 T. The results arise from the fact that the spectral intensity of the electromagnon critically depends on the magnetic structure. With changing the conical spin structures in terms of the conical angle ? from the proper screw (?=0) to the ferrimagnetic (?=90) through the conical spin-ordered phases (0

  14. Herbivory and Body Size: Allometries of Diet Quality and Gastrointestinal Physiology, and Implications for Herbivore Ecology and Dinosaur Gigantism

    PubMed Central

    Clauss, Marcus; Steuer, Patrick; Mller, Dennis W. H.; Codron, Daryl; Hummel, Jrgen

    2013-01-01

    Digestive physiology has played a prominent role in explanations for terrestrial herbivore body size evolution and size-driven diversification and niche differentiation. This is based on the association of increasing body mass (BM) with diets of lower quality, and with putative mechanisms by which a higher BM could translate into a higher digestive efficiency. Such concepts, however, often do not match empirical data. Here, we review concepts and data on terrestrial herbivore BM, diet quality, digestive physiology and metabolism, and in doing so give examples for problems in using allometric analyses and extrapolations. A digestive advantage of larger BM is not corroborated by conceptual or empirical approaches. We suggest that explanatory models should shift from physiological to ecological scenarios based on the association of forage quality and biomass availability, and the association between BM and feeding selectivity. These associations mostly (but not exclusively) allow large herbivores to use low quality forage only, whereas they allow small herbivores the use of any forage they can physically manage. Examples of small herbivores able to subsist on lower quality diets are rare but exist. We speculate that this could be explained by evolutionary adaptations to the ecological opportunity of selective feeding in smaller animals, rather than by a physiologic or metabolic necessity linked to BM. For gigantic herbivores such as sauropod dinosaurs, other factors than digestive physiology appear more promising candidates to explain evolutionary drives towards extreme BM. PMID:24204552

  15. Gigantic enhancement in the dielectric properties of polymer-based composites using core/shell MWCNT/amorphous carbon nanohybrids.

    PubMed

    Guo, Qikai; Xue, Qingzhong; Sun, Jin; Dong, Mingdong; Xia, Fujun; Zhang, Zhongyang

    2015-02-28

    Novel core/shell structured multi-walled carbon nanotube/amorphous carbon (MWCNT@AC) nanohybrids were successfully prepared using a simple and novel method. Subsequently, the MWCNT@AC nanohybrids were used as fillers to enhance the dielectric properties of poly(vinylidene fluoride) (PVDF) based composites. It is found that the dielectric constant of the MWCNT@AC/PVDF composites can reach 5910 (the dielectric loss is ?2), which is considerably better than that of MWCNT/PVDF composites. The uniform amorphous carbon shell provides an insulative layer between adjacent MWCNTs in the polymer matrix, which not only prevents the direct contact of MWCNTs but also improves the dispersibility of the MWCNTs. Therefore, a surprising number of microcapacitors could be formed in the composites before the formation of a conductive network, leading to a gigantic enhancement in the dielectric properties. Our strategy provides a new approach to fabricate excellent dielectric materials for energy storage capacitors. In addition, the design concept used in this work can be extended to other carbon materials. PMID:25640081

  16. Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda.

    PubMed

    Olson, Storrs L; Hearty, Paul J

    2010-12-23

    During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis. PMID:20554560

  17. What Lies Beneath: Sub-Articular Long Bone Shape Scaling in Eutherian Mammals and Saurischian Dinosaurs Suggests Different Locomotor Adaptations for Gigantism

    PubMed Central

    Bonnan, Matthew F.; Wilhite, D. Ray; Masters, Simon L.; Yates, Adam M.; Gardner, Christine K.; Aguiar, Adam

    2013-01-01

    Eutherian mammals and saurischian dinosaurs both evolved lineages of huge terrestrial herbivores. Although significantly more saurischian dinosaurs were giants than eutherians, the long bones of both taxa scale similarly and suggest that locomotion was dynamically similar. However, articular cartilage is thin in eutherian mammals but thick in saurischian dinosaurs, differences that could have contributed to, or limited, how frequently gigantism evolved. Therefore, we tested the hypothesis that sub-articular bone, which supports the articular cartilage, changes shape in different ways between terrestrial mammals and dinosaurs with increasing size. Our sample consisted of giant mammal and reptile taxa (i.e., elephants, rhinos, sauropods) plus erect and non-erect outgroups with thin and thick articular cartilage. Our results show that eutherian mammal sub-articular shape becomes narrow with well-defined surface features as size increases. In contrast, this region in saurischian dinosaurs expands and remains gently convex with increasing size. Similar trends were observed in non-erect outgroup taxa (monotremes, alligators), showing that the trends we report are posture-independent. These differences support our hypothesis that sub-articular shape scales differently between eutherian mammals and saurischian dinosaurs. Our results show that articular cartilage thickness and sub-articular shape are correlated. In mammals, joints become ever more congruent and thinner with increasing size, whereas archosaur joints remained both congruent and thick, especially in sauropods. We suggest that gigantism occurs less frequently in mammals, in part, because joints composed of thin articular cartilage can only become so congruent before stress cannot be effectively alleviated. In contrast, frequent gigantism in saurischian dinosaurs may be explained, in part, by joints with thick articular cartilage that can deform across large areas with increasing load. PMID:24130690

  18. Nanoscale assemblies of gigantic molecular {Mo154}-rings: (dimethyldioctadecylammonium)20[Mo154O462H8(H2O)70].

    PubMed

    Akutagawa, Tomoyuki; Jin, Reina; Tunashima, Ryo; Noro, Shin-Ichiro; Cronin, Leroy; Nakamura, Takayoshi

    2008-01-01

    Clusters based on the mixed-valence gigantic inorganic ring [Mo154O462H14(H2O)70]14- ({Mo154}-ring) and dimethyldioctadecylammonium (DODA) were combined to form novel molecular assemblies of an inorganic-organic hybrid molecular system as Langmuir-Blodgett (LB) and cast films. (DODA)20[Mo154O462H8(H2O)70] (2) was prepared by cation exchange and was characterized by a combination of thermogravimetry, IR, UV-vis-NIR, 1H NMR, and XRD measurements. The salt 2 was soluble in common organic solvents, and the chemical stability of {Mo154}-ring encapsulated by DODA cationic surfactants in CHCl3 was found to be higher than that of the "native" sodium salt of the {Mo154}-ring in H2O. Uniform spherical vesicle-like molecular assemblies of (DODA)20[Mo154O462H8(H2O)70] were observed in dilute THF, whose average diameter of 95 nm and a normalized variance of 5.7% were confirmed by a X-ray small-angle scattering. Deposition of 2 as a cast film showed circular domains with a typical diameter of approximately 100 nm, indicating possible similarities between solution and surface-deposited structures. The resulting LB films of salt 2 were transferred from an acidic buffer subphase with pH = 1.5 onto mica, giving a two-dimensional film surface with a unity transfer ratio. Further, the electronic absorption spectra of the LB multilayer were consistent with the classic type II mixed-valence MoV/MoVI electronic state well know for molybdenum blue {Mo154}-ring systems, and it appears that on the surface the plane of the {Mo154}-ring is approximately parallel to the substrate surface, as indicated by polarized electronic spectra, while the alkyl chains of DODA were relatively normal to the substrate surface. Therefore, the layer between the {Mo154}-rings and DODA cations was alternately stacked along the direction of film propagation. Finally, it was found that the surface morphology of the cast and LB films was determined by the molecular assembly of (DODA)20[Mo154O462H8(H2O)70] in solution and the air-water interface, respectively. PMID:18041852

  19. Reduced predator species richness drives the body gigantism of a frog species on the Zhoushan Archipelago in China.

    PubMed

    Li, Yiming; Xu, Feng; Guo, Zhongwei; Liu, Xuan; Jin, Changnan; Wang, Yanping; Wang, Supen

    2011-01-01

    1. Shifts in the body size of insular vertebrates have been an interesting theme in ecological and evolutionary studies. Four primary factors, including predation pressures, resource availability, inter-species competition and immigrant selection, have been proposed to explain the trend in insular body size. Life-history theory predicts that body size, average age, the proportion of old-aged members and the density of insular populations are negatively correlated with predator species richness, and that body size and population density are positively related to resource availability. The niche expansion hypothesis argues that a positive relationship is expected to exist between insular body size and prey size, which varies in response to extinction due to small or large competitors. The immigrant hypothesis predicts that insular body size is positively correlated with distance to the mainland. 2. We tested these hypotheses by using populations of rice frogs Rana limnocharis on 20 islands in the Zhoushan Archipelago and two sites of nearby mainland China. 3. The body size (snout-vent length) of rice frogs on half of the islands was larger before and after the variable of age was controlled for; rice frog density and prey availability was higher and prey size was larger on most of the islands as compared to the two mainland sites. On the islands, the body size and other features [e.g. average age, the proportion of old-aged frogs (ages 3 and 4) and density] of the rice frogs were negatively associated with predator species richness; female body size and other features were positively associated with prey availability. The inference of multivariate linear models based on corrected Akaike Information Criterion (AIC(c) ) showed that the relative importance of predator species richness on body size and each of the other features was larger than that of prey availability, prey size and distance to the mainland. In addition, the parameters for predator species richness were all negative. 4. The results provided strong support for the life-history theory of predation pressures, but weak evidence for the life-history theory of prey availability, the niche expansion or the immigrant hypothesis. The reduced predator species richness was a dominant factor contributing to the body gigantism of rice frogs on the islands. PMID:20840555

  20. No More Gigantism

    ERIC Educational Resources Information Center

    Vohra, B. B.

    1975-01-01

    The food situation in India is critical. It requires the development of both land and water resources, both of which are largely untapped. Ground water is one undeveloped resource that can help alleviate the irrigation problems facing agriculture. More efficient utilization could free millions of hectares of land for cultivation. (MA)

  1. Acromegalic gigantism, physicians and body snatching. Past or present?

    PubMed

    de Herder, Wouter W

    2012-09-01

    The skeletons of 2 famous acromegalic giants: Charles Byrne (1761-1783) and Henri Cot = Joseph Dusorc (1883-1912) and the embalmed body of the famous acromegalic giant douard Beaupr (1881-1904) all ended up in the medical collections of museums despite the fact that these patients had never donated or even refused to donate their corpses, nor had their relatives given permission. The corpse of the acromegalic giant John Aasen (1890-1938) was voluntarily donated to a physician annex collector of trivia from acromegalic giants. The autopsy on the acromegalic giant John Turner (1874-1911) was performed during his funeral ceremony without the relatives being informed. Only recently, the acromegalic giant Alexander Sizonenko (1959-2012) was made a financial offer during his life in exchange for his body after his death. The case-histories of these 6 patients and also the circumstances that led to the (in-) voluntary donation of their bodies are reviewed. PMID:22481633

  2. Genomic Gigantism: DNA Loss Is Slow in Mountain Grasshoppers

    Microsoft Academic Search

    Douda Bensasson; Dmitri A. Petrov; De-Xing Zhang; Daniel L. Hartl; Godfrey M. Hewitt

    Several studies have shown DNA loss to be inversely correlated with genome size in animals. These studies include a comparison between Drosophila and the cricket, Laupala, but there has been no assessment of DNA loss in insects with very large genomes. Podisma pedestris, the brown mountain grasshopper, has a genome over 100 times as large as that of Drosophila and

  3. Gigantism, temperature and metabolic rate in terrestrial poikilotherms

    PubMed Central

    Makarieva, Anastassia M; Gorshkov, Victor G; Li, Bai-Lian

    2005-01-01

    The mechanisms dictating upper limits to animal body size are not well understood. We have analysed body length data for the largest representatives of 24 taxa of terrestrial poikilotherms from tropical, temperate and polar environments. We find that poikilothermic giants on land become twothree times shorter per each 10 degrees of decrease in ambient temperature. We quantify that this diminution of maximum body size accurately compensates the drop of metabolic rate dictated by lower temperature. This supports the idea that the upper limit to body size within each taxon can be set by a temperature-independent critical minimum value of mass-specific metabolic rate, a fall below which is not compatible with successful biological performance. PMID:16191647

  4. Gigantic optical nonlinearity in one-dimensional Mott-Hubbard insulators

    NASA Astrophysics Data System (ADS)

    Kishida, H.; Matsuzaki, H.; Okamoto, H.; Manabe, T.; Yamashita, M.; Taguchi, Y.; Tokura, Y.

    2000-06-01

    The realization of all-optical switching, modulating and computing devices is an important goal in modern optical technology. Nonlinear optical materials with large third-order nonlinear susceptibilities (?(3)) are indispensable for such devices, because the magnitude of this quantity dominates the device performance. A key strategy in the development of new materials with large nonlinear susceptibilities is the exploration of quasi-one-dimensional systems, or `quantum wires'-the quantum confinement of electron-hole motion in one-dimensional space can enhance ? (3). Two types of chemically synthesized quantum wires have been extensively studied: the band insulators of silicon polymers, and Peierls insulators of ?-conjugated polymers and platinum halides. In these systems, ?(3) values of 10-12 to 10-7 e.s.u. (electrostatic system of units) have been reported. Here we demonstrate an anomalous enhancement of the third-order nonlinear susceptibility in a different category of quantum wires: one-dimensional Mott insulators of 3 d transition-metal oxides and halides. By analysing the electroreflectance spectra of these compounds, we measure ?(3) values in the range 10-8 to 10-5 e.s.u. The anomalous enhancement results from a large dipole moment between the lowest two excited states of these systems.

  5. Mammosomatotroph adenoma of the pituitary associated with gigantism and hyperprolactinemia. A morphological study including immunoelectron microscopy

    Microsoft Academic Search

    I. A. Felix; E. Horvath; K. Kovacs; H. S. Smyth; D. W. Killinger; J. Vale

    1986-01-01

    A 29-year old giantess with growth hormone excess and hyperprolactinemia underwent transsphenoidal surgery to remove her pituitary tumor. Electron microscopy revealed a mammosomatotroph adenoma composed of one cell type. Immunoelectron microscopy, using the immunogold technique, demonstrated predominantly growth hormone or prolactin or a varying mixture of both growth hormone and prolactin in the adenoma cells. The presence of growth hormone

  6. Evolution of Gigantism in Amphiumid Salamanders Ronald M. Bonett1,2

    E-print Network

    Wake, David B.

    closely related salamander families and fossil amphiumids from the Upper Cretaceous and Paleocene, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared

  7. Hard magnetic ferrite with a gigantic coercivity and high frequency millimetre wave rotation

    PubMed Central

    Namai, Asuka; Yoshikiyo, Marie; Yamada, Kana; Sakurai, Shunsuke; Goto, Takashi; Yoshida, Takayuki; Miyazaki, Tatsuro; Nakajima, Makoto; Suemoto, Tohru; Tokoro, Hiroko; Ohkoshi, Shin-ichi

    2012-01-01

    Magnetic ferrites such as Fe3O4 and Fe2O3 are extensively used in a range of applications because they are inexpensive and chemically stable. Here we show that rhodium-substituted ?-Fe2O3, ?-RhxFe2?xO3 nanomagnets prepared by a nanoscale chemical synthesis using mesoporous silica as a template, exhibit a huge coercive field (Hc) of 27 kOe at room temperature. Furthermore, a crystallographically oriented sample recorded an Hc value of 31 kOe, which is the largest value among metal-oxide-based magnets and is comparable to those of rare-earth magnets. In addition, ?-RhxFe2?xO3 shows high frequency millimetre wave absorption up to 209 GHz. ?-Rh0.14Fe1.86O3 exhibits a rotation of the polarization plane of the propagated millimetre wave at 220 GHz, which is one of the promising carrier frequencies (the window of air) for millimetre wave wireless communications. PMID:22948817

  8. Gigantism in honeybees: Apis cerana queens reared in mixed-species colonies

    NASA Astrophysics Data System (ADS)

    Tan, Ken; Hepburn, H. R.; He, Shaoyu; Radloff, S. E.; Neumann, P.; Fang, Xiang

    2006-07-01

    The development of animals depends on both genetic and environmental effects to a varying extent. Their relative influences can be evaluated in the social insects by raising the intracolonial diversity to an extreme in nests consisting of workers from more than one species. In this study, we studied the effects of mixed honeybee colonies of Apis mellifera and Apis cerana on the rearing of grafted queen larvae of A. cerana. A. mellifera sealed worker brood was introduced into A. cerana colonies and on emergence, the adults were accepted. Then, A. cerana larvae were grafted for queen rearing into two of these mixed-species colonies. Similarly, A. cerana larvae and A. mellifera larvae were also grafted conspecifically as controls. The success rate of A. cerana queen rearing in the test colonies was 64.5%, surpassing all previous attempts at interspecific queen rearing. After emergence, all virgin queens obtained from the three groups ( N=90) were measured morphometrically. The A. cerana queens from the mixed-species colonies differed significantly in size and pigmentation from the A. cerana control queens and closely approximated the A. mellifera queens. It is inferred that these changes in the A. cerana queens reared in the mixed-species colonies can be attributed to feeding by heterospecific nurse bees and/or chemical differences in royal jelly. Our data show a strong impact of environment on the development of queens. The results further suggest that in honeybees the cues for brood recognition can be learned by heterospecific workers after eclosion, thereby providing a novel analogy to slave making in ants.

  9. Address\\/memory management for a gigantic LISP environment or, GC considered harmful

    Microsoft Academic Search

    Jon L. White

    1980-01-01

    The possibility of incredibly cheap, fantastically large media for storage gives rise to a realistic LISP memory management scheme under which GC may be postponed for days, or even indefinitely; the idea is encapsulated in the acronym DDIGC? Don't Do It!. Tertiary memory is used to archive pages of the LISP environment which are perhaps reclaimable, but which have not

  10. A step to the gigantic genome of the desert locust: chromosome sizes and repeated DNAs.

    PubMed

    Camacho, J P M; Ruiz-Ruano, F J; Martn-Blzquez, R; Lpez-Len, M D; Cabrero, J; Lorite, P; Cabral-de-Mello, D C; Bakkali, M

    2015-06-01

    The desert locust (Schistocerca gregaria) has been used as material for numerous cytogenetic studies. Its genome size is estimated to be 8.55Gb of DNA comprised in 11 autosomes and the X chromosome. Its X0/XX sex chromosome determinism therefore results in females having 24 chromosomes whereas males have 23. Surprisingly, little is known about the DNA content of this locust's huge chromosomes. Here, we use the Feulgen Image Analysis Densitometry and C-banding techniques to respectively estimate the DNA quantity and heterochromatin content of each chromosome. We also identify three satellite DNAs using both restriction endonucleases and next-generation sequencing. We then use fluorescent in situ hybridization to determine the chromosomal location of these satellite DNAs as well as that of six tandem repeat DNA gene families. The combination of the results obtained in this work allows distinguishing between the different chromosomes not only by size, but also by the kind of repetitive DNAs that they contain. The recent publication of the draft genome of the migratory locust (Locusta migratoria), the largest animal genome hitherto sequenced, invites for sequencing even larger genomes. S. gregaria is a pest that causes high economic losses. It is thus among the primary candidates for genome sequencing. But this species genome is about 50% larger than that of L. migratoria, and although next-generation sequencing currently allows sequencing large genomes, sequencing it would mean a greater challenge. The chromosome sizes and markers provided here should not only help planning the sequencing project and guide the assembly but would also facilitate assigning assembled linkage groups to actual chromosomes. PMID:25472934

  11. Cryptococcus neoformans Capsular Enlargement and Cellular Gigantism during Galleria mellonella Infection

    PubMed Central

    Garca-Rodas, Roco; Casadevall, Arturo; Rodrguez-Tudela, Juan Lus; Cuenca-Estrella, Manuel; Zaragoza, Oscar

    2011-01-01

    We have studied infection of Cryptococcus neoformans in the non-vertebrate host Galleria mellonella with particular interest in the morphological response of the yeast. Inoculation of C. neoformans in caterpillars induced a capsule-independent increase in haemocyte density 2 h after infection. C. neoformans manifested a significant increase in capsule size after inoculation into the caterpillar. The magnitude of capsule increase depended on the temperature, being more pronounced at 37C than at 30C, which correlated with an increased virulence of the fungus and reduced phagocytosis at 37C. Capsule enlargement impaired phagocytosis by haemocytes. Incubation of the yeast in G. mellonella extracts also resulted in capsule enlargement, with the polar lipidic fraction having a prominent role in this effect. During infection, the capsule decreased in permeability. A low proportion of the cells (<5%) recovered from caterpillars measured more than 30 m and were considered giant cells. Giant cells recovered from mice were able to kill the caterpillars in a manner similar to regular cells obtained from in vivo or grown in vitro, establishing their capacity to cause disease. Our results indicate that the morphological transitions exhibited by C. neoformans in mammals also occur in a non-vertebrate host system. The similarities in morphological transitions observed in different animal hosts and in their triggers are consistent with the hypothesis that the cell body and capsular responses represent an adaptation of environmental survival strategies to pathogenesis. PMID:21915338

  12. Sudden pressure increase in magma reservoir triggered by gigantic lava-dome collapse on Montserrat

    NSDL National Science Digital Library

    Voight et al.

    Dilatometers recorded pressure changes within the Soufrire Hills Volcano's magma chamber during the 13 July 2003 collapse of its? lava dome. Strain data was evaluated to determine the depth of the pressure source. Results suggest an ellipsoidal magma chamber source at a depth of roughly six kilometers and an average radius of about one kilometer. The observed increase in pressure was consistent with the magma containing pressurized bubbles that expanded when the ambient pressure was reduced.

  13. Low levels of LTR retrotransposon deletion by ectopic recombination in the gigantic genomes of salamanders.

    PubMed

    Frahry, Matthew Blake; Sun, Cheng; Chong, Rebecca A; Mueller, Rachel Lockridge

    2015-02-01

    Across the tree of life, species vary dramatically in nuclear genome size. Mutations that add or remove sequences from genomes-insertions or deletions, or indels-are the ultimate source of this variation. Differences in the tempo and mode of insertion and deletion across taxa have been proposed to contribute to evolutionary diversity in genome size. Among vertebrates, most of the largest genomes are found within the salamanders, an amphibian clade with genome sizes ranging from ~14 to ~120 Gb. Salamander genomes have been shown to experience slower rates of DNA loss through small (i.e., <30 bp) deletions than do other vertebrate genomes. However, no studies have addressed DNA loss from salamander genomes resulting from larger deletions. Here, we focus on one type of large deletion-ectopic-recombination-mediated removal of LTR retrotransposon sequences. In ectopic recombination, double-strand breaks are repaired using a "wrong" (i.e., ectopic, or non-allelic) template sequence-typically another locus of similar sequence. When breaks occur within the LTR portions of LTR retrotransposons, ectopic-recombination-mediated repair can produce deletions that remove the internal transposon sequence and the equivalent of one of the two LTR sequences. These deletions leave a signature in the genome-a solo LTR sequence. We compared levels of solo LTRs in the genomes of four salamander species with levels present in five vertebrates with smaller genomes. Our results demonstrate that salamanders have low levels of solo LTRs, suggesting that ectopic-recombination-mediated deletion of LTR retrotransposons occurs more slowly than in other vertebrates with smaller genomes. PMID:25608479

  14. The Pulp gigantic geode (Almera, Spain): geology, metal pollution, microclimatology, and conservation

    NASA Astrophysics Data System (ADS)

    Fernndez-Corts, ngel; Calaforra, Jos Mara; Garca-Guinea, Javier

    2006-07-01

    The discovery of the giant Geode of Pulp (Almera, Spain) was considered as an important highlight in the geological heritage of Spain. Projects developed for their conservation were immediately initiated with legal figures of protection and tourist projects. The Geode has a tourist interest, which must be tempered by environmental restrictions limiting the public visits. First results demonstrate that a continuous visit of two or three people for more than 10 min provokes the appearance of condensation and risks corrosion of the gypsum crystals. In addition, the electron microprobe analyses confirms (1) the hydrothermal phases of iron-manganese in carbonated host rock; (2) the presence of sulphides with Fe-Zn-Pb-Ag-Sb-Cu-Hg-As-Te-Se; and (3) Ba, Ca, and Sr sulphates with mercury traces. The present proposal to label the geode and the mining environment as geological-natural heritage is feasible, although any tourist adaptation must not permit visits to the geode indoor and Hg levels must be controlled.

  15. Occurrence of gigantic biogenic magnetite during the Paleocene-Eocene Thermal Maximum

    Microsoft Academic Search

    D. Schumann; T. D. Raub; R. E. Kopp; J. L. Guerquin-Kern; T. D. Wu; I. Rouiller; A. V. Smirnov; S. K. Sears; U. Lcken; S. M. Tikoo; R. Hesse; J. L. Kirschvink; H. Vali

    2009-01-01

    The Paleocene-Eocene Thermal Maximum (PETM) is one of the most severe climatic events of the Cenozoic Era. A massive injection of light carbon into the oceans and atmosphere over a few thousand of years triggered drastic perturbation of Earth's climate resulting in abrupt global warming of ~5-9oC [Sluijs et al., 2007] that persisted for ~180,000 years. This episode is marked

  16. Ultrafast mass transport during decay of gigantic Pb mesas on Ni(111)

    NASA Astrophysics Data System (ADS)

    Poelsema, Bene

    2012-02-01

    We have studied the initial growth of Pb films on Ni(111) at elevated temperatures of 424 K and 474 K. Quantum Well States (QWS's) have been found to be responsible for the morphology of these Pb films on Ni(111). The delicate balance between surface energies, elastic energies and QWS's is initially tilted towards QWS's, as discrete layer heights are observed. First, a strong preference for 5 and 7 layers high, flat topped Pb islands is observed, showing several striking similarities with Pb films on Si(111) and on Cu(111). Key examples of these will be discussed. When the character of the rough film gradually changes from 2D to 3D, the balance between these forces becomes more and more dominated by interfacial energies. A tipping point is reached by very slowly heating the surface to about 520 K. As the energetic balance is tipped for good in favor of the interface free energy, the electronically stabilized, extended, about 40 layers high mesas suddenly decay towards compact hemispheric structures. The spectacular speed at which the transition takes place (billions of atoms move over several microns during a few milliseconds!) is many orders of magnitude larger than what is expected, based on arguments involving thermally activated behavior on atomic scales. I will discuss peculiarities of the wetting layer and its changes, which appear to coincide with the ultrafast transition of the film morphology. With a widespread interest in nanostructures in general, our results illustrate the generic need to characterize all aspects of nanostructures, both structural and electronic, since small excursions away from equilibrium can have dramatic consequences. T.R.J. Bollmann, R. van Gastel, H.J.W. Zandvliet and B. Poelsema; Phys. Rev. Lett. 107, 116101 (2011); T.R.J. Bollmann, R. van Gastel, H.J.W. Zandvliet and B. Poelsema; New J. Phys. 13, 103025 (2011).

  17. A gigantic shark from the lower cretaceous duck creek formation of Texas.

    PubMed

    Frederickson, Joseph A; Schaefer, Scott N; Doucette-Frederickson, Janessa A

    2015-01-01

    Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks. Regardless of its actual identification, this new specimen provides further evidence that large-bodied lamniform sharks had evolved prior to the Late Cretaceous. PMID:26039066

  18. The parasitic castration and gigantism of Lymnaea truncatula infected with the larval stages of Fasciola hepatica

    Microsoft Academic Search

    R. A. Wilson; Jean Denison

    1980-01-01

    The shells ofLymnaea truncatula infected with the larval stages ofFasciola hepatica were significantly longer than those of comparable uninfected controls. The dry mass (tissue, shell+parasite) of the same infected snails, 56 days after infection, was approximately twice that of the controls (tissue+shell). The increased mass of infected snails was not due to a disproportionate increase in shell weight relative to

  19. Hard magnetic ferrite with a gigantic coercivity and high frequency millimetre wave rotation.

    PubMed

    Namai, Asuka; Yoshikiyo, Marie; Yamada, Kana; Sakurai, Shunsuke; Goto, Takashi; Yoshida, Takayuki; Miyazaki, Tatsuro; Nakajima, Makoto; Suemoto, Tohru; Tokoro, Hiroko; Ohkoshi, Shin-ichi

    2012-01-01

    Magnetic ferrites such as Fe(3)O(4) and Fe(2)O(3) are extensively used in a range of applications because they are inexpensive and chemically stable. Here we show that rhodium-substituted ?-Fe(2)O(3), ?-Rh(x)Fe(2-x)O(3) nanomagnets prepared by a nanoscale chemical synthesis using mesoporous silica as a template, exhibit a huge coercive field (H(c)) of 27 kOe at room temperature. Furthermore, a crystallographically oriented sample recorded an H(c) value of 31 kOe, which is the largest value among metal-oxide-based magnets and is comparable to those of rare-earth magnets. In addition, ?-Rh(x)Fe(2-x)O(3) shows high frequency millimetre wave absorption up to 209 GHz. ?-Rh(0.14)Fe(1.86)O(3) exhibits a rotation of the polarization plane of the propagated millimetre wave at 220 GHz, which is one of the promising carrier frequencies (the window of air) for millimetre wave wireless communications. PMID:22948817

  20. Gigantism in unique biogenic magnetite at the PaleoceneEocene Thermal Maximum

    PubMed Central

    Schumann, Dirk; Raub, Timothy D.; Kopp, Robert E.; Guerquin-Kern, Jean-Luc; Wu, Ting-Di; Rouiller, Isabelle; Smirnov, Aleksey V.; Sears, S. Kelly; Lcken, Uwe; Tikoo, Sonia M.; Hesse, Reinhard; Kirschvink, Joseph L.; Vali, Hojatollah

    2008-01-01

    We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the PaleoceneEocene Thermal Maximum (PETM) in a borehole at Ancora, NJ. Aside from previously described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4 ?m long and hexaoctahedral prisms up to 1.4 ?m long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailabilitya product of dramatic changes in weathering and sedimentation patterns driven by severe global warmingdrove diversification of magnetite-forming organisms, likely including eukaryotes. PMID:18936486

  1. A Gigantic Shark from the Lower Cretaceous Duck Creek Formation of Texas

    PubMed Central

    Frederickson, Joseph A.; Schaefer, Scott N.; Doucette-Frederickson, Janessa A.

    2015-01-01

    Three large lamniform shark vertebrae are described from the Lower Cretaceous of Texas. We interpret these fossils as belonging to a single individual with a calculated total body length of 6.3 m. This large individual compares favorably to another shark specimen from the roughly contemporaneous Kiowa Shale of Kansas. Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks. Regardless of its actual identification, this new specimen provides further evidence that large-bodied lamniform sharks had evolved prior to the Late Cretaceous. PMID:26039066

  2. Drosophila Dumpy is a gigantic extracellular protein required to maintain tension at epidermalcuticle attachment sites

    Microsoft Academic Search

    M. B. Wilkin; M. N. Becker; D. Mulvey; I. Phan; A. Chao; K. Cooper; H. J. Chung; I. D. Campbell; M. Baron; R. MacIntyre

    2000-01-01

    Background: Growth and morphogenesis during development depend both on patterning genes, which assign positional information, and on genes that regulate mechanical forces. The dumpy gene of the fruit fly Drosophila melanogaster is an example of the latter class, with mutant phenotypes affecting size and shape of the limbs, thoracic cuticle, trachea and mouthparts.Results: The genetically complex dumpy locus was found

  3. Radial head dislocation due to gigantic solitary osteochondroma of the proximal ulna: case report and literature review.

    PubMed

    Hamada, Yoshitaka; Hibino, Naohito; Horii, Emiko

    2015-06-01

    Developmental anterior dislocation of the radial head resulting from a congenital solitary osteochondroma of the proximal ulna is an extremely rare condition. We present a case of a 4-year-old girl with this condition affecting her right elbow, which was treated by a trapezoidal shortening osteotomy at the radial neck following an oblique ulnar osteotomy with angulation and elongation after a complete resection of the tumor mass. The child remained asymptomatic with symmetric carrying angles during 2.5years of follow-up post-surgery. We discuss the nature of this condition and review the literature. PMID:26034449

  4. End-Permian catastrophe by a bolide impact: Evidence of a gigantic release of sulfur from the mantle

    Microsoft Academic Search

    Kunio Kaiho; Yoshimichi Kajiwara; Takanori Nakano; Yasunori Miura; Hodaka Kawahata; Kazue Tazaki; Masato Ueshima; Zhongqiang Chen; Guang R. Shi

    2001-01-01

    Our studies in southern China have revealed a remarkable sulfur and strontium isotope excursion at the end of the Permian, along with a coincident concentration of impact- metamorphosed grains and kaolinite and a significant decrease in manganese, phosphorous, calcium, and microfossils (foraminifera). These data suggest that an asteroid or a comet hit the ocean at the end of Permian time

  5. A Syndrome of Multiorgan Hyperplasia with Features of Gigantism, Tumorigenesis, and Female Sterility in p27 Kip1 Deficient Mice

    Microsoft Academic Search

    Matthew L Fero; Michael Rivkin; Michael Tasch; Peggy Porter; Catherine E Carow; Eduardo Firpo; Kornelia Polyak; Li-Huei Tsai; Virginia Broudy; Roger M Perlmutter; Kenneth Kaushansky; James M Roberts

    1996-01-01

    Targeted disruption of the murine p27Kip1 gene caused a gene dosedependent increase in animal size without other gross morphologic abnormalities. All tissues were enlarged and contained more cells, although endocrine abnormalities were not evident. Thymic hyperplasia was associated with increased T lymphocyte proliferation, and T cells showed enhanced IL-2 responsiveness in vitro. Thus, p27 deficiency may cause a cell-autonomous defect

  6. A Gigantic Sarcopterygian (Tetrapodomorph Lobe-Finned Fish) from the Upper Devonian of Gondwana (Eden, New South Wales, Australia)

    PubMed Central

    Young, Ben; Dunstone, Robert L.; Senden, Timothy J.; Young, Gavin C.

    2013-01-01

    Edenopteron keithcrooki gen. et sp. nov. is described from the Famennian Worange Point Formation; the holotype is amongst the largest tristichopterids and sarcopterygians documented by semi-articulated remains from the Devonian Period. The new taxon has dentary fangs and premaxillary tusks, features assumed to be derived for large Northern Hemisphere tristichopterids (Eusthenodon, Hyneria, Langlieria). It resembles Eusthenodon in ornament, but is distinguished by longer proportions of the parietal compared to the post-parietal shield, and numerous differences in shape and proportions of other bones. Several characters (accessory vomers in the palate, submandibulars overlapping ventral jaw margin, scales ornamented with widely-spaced deep grooves) are recorded only in tristichopterids from East Gondwana (Australia-Antarctica). On this evidence Edenopteron gen. nov. is placed in an endemic Gondwanan subfamily Mandageriinae within the Tristichopteridae; it differs from the nominal genotype Mandageria in its larger size, less pointed skull, shape of the orbits and other skull characters. The hypothesis that tristichopterids evolved in Laurussia and later dispersed into Gondwana, and a derived subgroup of large Late Devonian genera dispersed from Gondwana, is inconsistent with the evidence of the new taxon. Using oldest fossil and most primitive clade criteria the most recent phylogeny resolves South China and Gondwana as areas of origin for all tetrapodomorphs. The immediate outgroup to tristichopterids remains unresolved either Spodichthys from Greenland as recently proposed, or Marsdenichthys from Gondwana, earlier suggested to be the sister group to all tristichopterids. Both taxa combine two characters that do not co-occur in other tetrapodomorphs (extratemporal bone in the skull; non-cosmoid round scales with an internal boss). Recently both primitive and derived tristichopterids have been discovered in the late Middle Devonian of both hemispheres, implying extensive ghost lineages within the group. Resolving their phylogeny and biogeography will depend on a comprehensive new phylogenetic analysis. PMID:23483884

  7. Gigantic diphoton rate of heavy Higgs bosons in the aligned two Higgs doublet models with small tan ?

    NASA Astrophysics Data System (ADS)

    Song, Jeonghyeon; Yoon, Yeo Woong

    2015-06-01

    We study the implications of the LHC heavy neutral Higgs boson search data on the aligned two Higgs doublet model with a softly broken Z2 symmetry. When tan ? is small, the gluon fusion production of the heavy C P -even scalar H0 or the C P -odd scalar A0 becomes large enough to constrain the model by the current ? ? , ?+?- , and t t data. By reinvestigating the indirect constraints from ? ? , b ?s ? , ? MBd , Rb, ?K , and the perturbativity of the running top quark Yukawa coupling, we find that the small tan ? region is still allowed: for instance, tan ? ?0.6 (0.5 ) for Type I and X (II and Y) for mH=800 GeV . We find that the current LHC results of the heavy Higgs searches at ?{s }=8 TeV are shown to put on more significant bounds. If mH?mA , the t t mode excludes tan ? ?1.5 for mH ,A=500 - 600 GeV in all four types, and the ? ? and ?+?- modes exclude tan ? ?1 - 3 (tan ? ?3 - 10 ) for mH ,A=150 - 340 GeV in Types I, II, and Y (Type X).

  8. Gigantic enhancement in response and reset time of ZnO UV nanosensor by utilizing Schottky contact and surface functionalization

    PubMed Central

    Zhou, Jun; Gu, Yudong; Hu, Youfan; Mai, Wenjie; Yeh, Ping-Hung; Bao, Gang; Sood, Ashok K.; Polla, Dennis L.; Wang, Zhong Lin

    2009-01-01

    UV response of ZnO nanowire nanosensor has been studied under ambient condition. By utilizing Schottky contact instead of Ohmic contact in device fabrication, the UV sensitivity of the nanosensor has been improved by four orders of magnitude, and the reset time has been drastically reduced from ?417 to ?0.8 s. By further surface functionalization with function polymers, the reset time has been reduced to ?20 ms even without correcting the electronic response of the measurement system. These results demonstrate an effective approach for building high response and fast reset UV detectors. PMID:19654881

  9. The Roza Member, Columbia River Basalt Group: A gigantic pahoehoe lava flow field formed by endogenous processes?

    Microsoft Academic Search

    T. Thordarson; S. Self

    1998-01-01

    We present studies on the physical volcanology of the ~15 Ma Roza Member of the Wanapum Formation in the Columbia River Basalt Group. The Roza Member represents a compound pahoehoe flood basalt lava flow field, with an area of ~40,300 km2 and a volume of ~1300 km3. It consists of 4 major lava flows each composed of numerous, decimeter to

  10. Gigantic optical Pockels effect in water within the electric double layer at the electrode-solution interface

    Microsoft Academic Search

    Yugo Nosaka; Masashi Hirabayashi; Takayoshi Kobayashi; Eiji Tokunaga

    2008-01-01

    We have obtained the experimental evidence for the Pockels effect of water, which is placed in the electric double layer (EDL) on the interface between the bulk water and a transparent electrode. The electric-field induced energy shift was observed for the visible interference fringes in a 300-nm indium-tin-oxide (ITO) electrode layer. The signal was shown to originate from a negative

  11. Crescimento ponderal de filhotes de tartaruga gigante da Amaznia (Podocnemis expansa) submetidos a tratamento com raes isocalricas contendo diferentes nveis de protena bruta

    Microsoft Academic Search

    Vinicius Augusto S; Leonardo C. Quintanilha; Gustavo Eduardo Freneau; Vera Lucia Ferreira Luz; Arcdio de Los Reyes Borja; Paulo Csar Silva

    2004-01-01

    RESUMO - A criao de Podocnemis expansa, a tartaruga-da-amaznia, com finalidade comercial foi implantada no Brasil em 1992. Contudo, muitas questes acerca do manejo, da nutrio, da sanidade e, principalmente, da reproduo ainda so obscuras. Visando contribuir para o desenvolvimento de uma metodologia alimentar da espcie, objetivou-se testar diferentes nveis de protena da dieta. Uma amostra de 480 animais neonatos

  12. Dual electron-phonon coupling model for gigantic photoenhancement of the dielectric constant and electronic conductivity in SrTi O3

    NASA Astrophysics Data System (ADS)

    Qiu, Y.; Wu, C. Q.; Nasu, K.

    2005-12-01

    In connection with the recent experimental discovery on photoenhancements of the electronic conductivity and the quasi-static electric susceptibility in SrTiO3 , we theoretically study a photogeneration mechanism of charged and conductive ferroelectric domains in this perovskite type quantum dielectric. The photo-generated electron, being quite itinerant in the 3d band of Ti4+ , is assumed to couple weakly but quadratically with soft-anharmonic T1u phonons in this quantum dielectric, in view of the parity of this lattice vibration. The photo-generated electron is also assumed to couple strongly but linearly with the breathing type high energy phonons. Using a tight-binding model for electrons, we will show that this dual electron-phonon coupling results in two types of polarons, a super-para-electric (SPE) large polaron with a quasi-globle parity violation, and an off-center type self-trapped polaron with only a local parity violation. This SPE large polaron is shown to be equal to a singly charged (e-) and conductive ferroelectric domain with a quasi-macroscopic range. Two of such large polarons are shown to aggregate and form an SPE large bipolaron, which is still conductive. Various other bipolaron clusters are also shown to be formed in this electron-phonon coupled system. These large polarons have a high mobility and an enhanced quasi-static dielectric susceptibility. Effect of adulteration is also discussed.

  13. Synergistic combination of multi-Zr(IV) cations and lacunary Keggin germanotungstates leading to a gigantic Zr24-cluster-substituted polyoxometalate.

    PubMed

    Huang, Ling; Wang, Sa-Sa; Zhao, Jun-Wei; Cheng, Lin; Yang, Guo-Yu

    2014-05-28

    Synergistic directing roles of six lacunary fragments resulted in an unprecedented Zr24-cluster substituted poly(polyoxotungstate) Na10K22[Zr24O22(OH)10(H2O)2(W2O10H)2(GeW9O34)4(GeW8O31)2]85H2O (Na10K22185H2O), which contains the largest [Zr24O22(OH)10(H2O)2] (Zr24) cluster in all the Zr-based poly(polyoxometalate)s to date. The most remarkable feature is that the centrosymmetric Zr24-cluster-based hexamer contains two symmetry-related [Zr12O11(OH)5(H2O)(W2O10H)(GeW9O34)2(GeW8O31)](16-) trimers via six ?3-oxo bridges and was simultaneously trapped by three types of different segments of B-?-GeW9O34, B-?-GeW8O31, and W2O10. The other interesting characteristic is that there are two pairs of intriguing triangular atom alignments: one is composed of the Zr(2,4,6,8,11) and W21 atoms and the other contains the Ge(1-3), Zr(3,5,7,9,10,12) and W26 atoms, and the Zr5 atom is inside the triangle; a linking mode is unobserved. The oxygenation reactions of thioethers by H2O2 were evaluated when Na10K22185H2O served as a catalyst. Results show that it is an effective catalyst for oxygenation of thioethers by H2O2. The unique redox property of oxygen-enriched polyoxotungstate fragments and Lewis acidity of the Zr cluster imbedded in Na10K22185H2O provide a sufficient driving force for the catalytic conversion from thioethers to sulfoxides/sulfones. PMID:24819708

  14. CARACTERIZACIN PARCIAL DEL COLGENO EXTRADO A PARTIR DEL MANTO, ALETA Y TENTCULOS DE CALAMAR GIGANTE (Dosidicus gigas) PARTIAL CHARACTERIZATION OF COLLAGEN FROM MANTLE, FIN, AND ARMS OF JUMBO SQUID (Dosidicus gigas)

    Microsoft Academic Search

    W. Torres-Arreola; R. Pacheco-Aguilar; R. R. Sotelo-Mundo; O. Rouzaud-Sndez; J. M. Ezquerra-Brauer

    2008-01-01

    In Dosidicus gigas or jumbo squid, collagen plays an important role in squid swimming mechanisms. Scarce information is available on collagen. The content as well some physical and chemical properties of pepsin-soluble (PSC) and insoluble collagen (IC) were compared in mantle, arm, and fin from adult fresh jumbo squid. The total collagen content and SDS-electrophoresis profile were different in each

  15. Fermi discovers giant bubbles in Milky Way - Duration: 93 seconds.

    NASA Video Gallery

    Using data from NASA's Fermi Gamma-ray Space Telescope, scientists have recently discovered a gigantic, mysterious structure in our galaxy. This feature looks like a pair of bubbles extending above...

  16. PEST&CROP INDEX 2007 INSECTS, MITES & NEMATODES

    E-print Network

    Ginzel, Matthew

    , and Beetles 13 What is That Gigantic Beetle - 16 Mexican Bean Beetle Millipede Expect the Unexpected When: Announcing New Website for Nematology 12 Nematode Update Should Corn Growers Be Alarmed About the New

  17. Internationales Festival fr zeitgenssischen Tanz der Landeshauptstadt Mnchen Bestellformular "Sen und Ernten. Zeitgenssischer Tanz aus Flandern"

    E-print Network

    Kersting, Roland

    of the Flemish dance scene resul- ting in a multifaceted view on the "Flemish Wave" with all its fascination, its, Meg Stuart und Bettina Wagner-Bergelt. Is the "Flemish Wave" just a gigantic wave of passion? What do

  18. Matrix Factorization as Search Kristian Kersting

    E-print Network

    Kaski, Samuel

    Abstract. Simplex Volume Maximization (SiVM) exploits distance ge- ometry for eciently factorizing gigantic examples of objects include text documents, digital images, genomes, stocks, or social groups. Examples

  19. The evolution of high energy accelerators

    SciTech Connect

    Courant, E.D.

    1989-10-01

    In this lecture I would like to trace how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to gigantic projects being hotly debated in Congress as well as in the scientific community.

  20. Beckwith-Wiedemann syndrome and bilateral adrenal pheochromocytoma: sonography and MRI findings.

    PubMed

    Baldisserotto, Matteo; Peletti, Adriana Barcellos; Angelo de Arajo, Manoel; Pertence, Ana Paula Cardoso; Dora, Marcelo Dourado; Maciel, Elines Oliva; Gaiger, Ana Maria

    2005-11-01

    Beckwith-Wiedemann syndrome is characterized by a group of clinical abnormalities, the most frequent of which are omphalocele, macroglossia, gigantism, neonatal hypoglycemia and umbilical hernia. The association of this syndrome with malignant tumors is well documented. We report a child with this syndrome associated with bilateral adrenal pheochromocytoma. PMID:15983774

  1. Alternative methodologies in studies on business failure: do they produce better results than the classical statistical methods?

    Microsoft Academic Search

    SOFIE BALCAEN; HUBERT OOGHE

    2004-01-01

    Over the last 35 years, the topic of company failure prediction has developed to a major research domain in corporate finance. Academic researchers from all over the world have been developing a gigantic number of corporate failure prediction models, based on various types of modelling techniques. Besides the classical cross-sectional statistical methods, which have produced numerous failure prediction models, researchers

  2. Income Inequality in the Attention Economy

    Microsoft Academic Search

    Kevin S. McCurley

    2007-01-01

    The World Wide Web may be viewed as a gigantic market for information. In this market there are producers (au- thors) and consumers (readers) and the currency for infor- mation is attention. In this paper we examine the distri- bution of attention across the World Wide Web. Through study of the habits of web users, we conclude that the cur-

  3. Soil Formation

    NSDL National Science Digital Library

    Humans use soil for their daily needs but do not sufficiently take account of its slow formation and fast loss. Discover the amazing geology of soil formation and the basic rock and soil types.Although soil seems the end product from weathering rocks, it is merely a stage in the gigantic cycle of mineral recycling by the movement of tectonic plates.

  4. Light Work

    Microsoft Academic Search

    Rebecca Cummins

    2005-01-01

    Modern day life and timekeepers have profoundly affected the way we conceptualize time and our position in the universe. Over the past year, I have been investigating the apparent movement of the Sun both sculpturally and photographically. In this paper, I discuss my collaborations with Woody Sullivan and highlight several of the sundials, both gigantic and intimate, created by University

  5. -.;A Sc,icnca ,Smvirso Peaturo *a+1msed upon receipt

    E-print Network

    t o the magnetic zenith and transform the vault of heaven into One gigantic, lustrous canopy contribute to ornament the vault. Here is the tender green of the emerald, the grand purple of the ruby moment tho glorious, luminous vault remains thus in majestic beauty. It i e tho auroral corona. Thon

  6. BotEC: The Right Eye of the Man in the Moon

    NSDL National Science Digital Library

    Barb Tewksbury

    Question The "right eye" of the Man in the Moon is really Mare Imbrium, the central portion of a gigantic multi-ring basin formed by a colossal meteorite impact several billion years ago. Which of the following is approximately the same size as Mare Imbrium? Choose from the Pacific Ocean, the North Atlantic Ocean, Australia, Texas, and New York State.

  7. Manicouagan: asteroid circuit by kayak Photographs: http://www.staff.science.uu.nl/~rutte101/travel-albums/manicouagan/album.html

    E-print Network

    Rutten, Rob

    on Earth, the subsequent ice ages, and a gigantic retention dam. It is shaped as a 10 km wide annulus the age of the dinosaurs and as bad as the K-T extinction ending it, is dated 13 My after the impact (the even worse 1 #12;Permian-Triassic "great dying" event took place 37 My before it). Ice ages: The recent

  8. Terrestrial mobile networks for Air-to-Ground communications of the General Aviation

    Microsoft Academic Search

    Chao Zhang

    2011-01-01

    General Aviation (GA) is destined to be an active area compared with airline scheduled civil aviation. The figures with much more aircrafts, pilots and private airports than airline aviation can be statistically obtained in a lot of countries, such as USA, UK. etc. In China, from 2011, the restriction of low attitude airspace is broken and there is a gigantic

  9. Novel near-ground navigation for General Aviation with terrestrial mobile networks

    Microsoft Academic Search

    Chao Zhang; Keke Pang

    2011-01-01

    General Aviation (GA) is really an active area compared with airline scheduled civil aviation. The figures with much more aircrafts, pilots and private airports than airline aviation can be statistically obtained in a lot of countries, such as US, UK etc. In China, from 2011, the restriction of low level space is broken and there is a gigantic plan for

  10. Detailed Moho Topography Beneath the Southern Lhasa Terrane, Tibet by Receiver Functions

    Microsoft Academic Search

    X. Li; D. Wei; X. Yuan; R. Kind; P. Kumar; H. Zhou

    2008-01-01

    The collision of the Indian and Asian plates since about 55Ma has created the most gigantic plateau with the thickest crust of the world. There is, however, no general agreement on the modes of the crustal thickening. Even the crustal thickness of the Tibetan plateau still remains poorly determined. While it is generally accepted that the Tibetan crust is roughly

  11. Colonia Mauricio. Two complementary visions

    Microsoft Academic Search

    Edgardo Zablotsky

    2012-01-01

    In 1891 Baron Maurice de Hirsch founded the Jewish Colonization Association (J.C.A.), which was to become one of the largest philanthropic firms of their time, conducting a gigantic experiment in social welfare consisting in the organized immigration of thousands of people from the Russian Empire to Argentina and setting up agricultural colonies. Colonia Mauricio, close to Carlos Casares, in the

  12. The Project of the Baron de Hirsch. Success or Failure? \\/ El proyecto del Barn de Hirsch. Exito o fracaso?

    Microsoft Academic Search

    Edgardo Zablotsky

    2005-01-01

    ENGLISH VERSION: In 1891, Baron Maurice de Hirsch founded the Jewish Colonization Association (J.C.A.), through which he would manage a gigantic social welfare project concerning the immigration of thousands of people from the Russian Empire towards Argentina, and their settlement in agricultural colonies. In this paper, we evaluate the result of this project, which is generally qualified as a failure

  13. Mol. Biol. Evol. 18(2):246253. 2001 2001 by the Society for Molecular Biology and Evolution. ISSN: 0737-4038

    E-print Network

    Hartl, Daniel L.

    . ISSN: 0737-4038 Genomic Gigantism: DNA Loss Is Slow in Mountain Grasshoppers Douda Bensasson,* Dmitri A pedestris, the brown mountain grasshopper, has a genome over 100 times as large as that of Drosophila and 10 lower in the grasshoppers studied than in Drosophila or Laupala. This suggests that the inverse

  14. Middlebury College Computer Science Seminar

    E-print Network

    Scharstein, Daniel

    real-time visual search in millions of images. I will also discuss how our image descriptor can be usedMiddlebury College Computer Science Seminar Visual Recognition and Search in Gigantic Image. Even when tags are available, they are often not accurate, rendering traditional text-search

  15. The Story of Semco: The Company that Humanized Work

    ERIC Educational Resources Information Center

    Vanderburg, David

    2004-01-01

    This article examines and analyzes Semco, a company that changed the way it viewed and treated its workers for the better. It is the contention of Semco's CEO, that at most large corporations "everyone is part of a gigantic, impersonal machine, and it is impossible to feel motivated when you feel you are just another cog. Human nature demands

  16. Molecular Clouds, Star Formation and Galactic Structure.

    ERIC Educational Resources Information Center

    Scoville, Nick; Young, Judith S.

    1984-01-01

    Radio observations show that the gigantic clouds of molecules where stars are born are distributed in various ways in spiral galaxies, perhaps accounting for the variation in their optical appearance. Research studies and findings in this area are reported and discussed. (JN)

  17. The gardens of Barrackpore

    Microsoft Academic Search

    Eugenia W. Herbert

    2007-01-01

    Barrackpore, in former times the country retreat of the Governor-General of India, lies some fifteen miles upriver from Calcutta. A short distance, one would think, but enough to guarantee a respite from the sweltering heat that descended on the capital of British India for much of the year. Its gigantic trees, luxuriant shrubbery, and gentle lawn sloping down to the

  18. Biol. Rev. (2011), 86, pp. 117155. 117 doi: 10.1111/j.1469-185X.2010.00137.x

    E-print Network

    Schne, Bernd R.

    2011-01-01

    and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals that sauropod gigantism was made possible by a specific combination of plesiomorphic characters (phylogenetic mastication and a gastric mill would have limited food uptake rate. Scaling relationships between

  19. Why did not the Ontong Java Plateau form subaerially?

    Microsoft Academic Search

    Jun KorenagaT

    2005-01-01

    A recent drilling leg on the Ontong Java Plateau and subsequent studies have consolidated the following observation for this gigantic oceanic plateau: The bulk of the plateau was formed at ~120 Ma in a submarine environment. This rapid construction of a massive igneous body below sea level is impossible to explain with the popular plume head hypothesis. Though the bolide

  20. Coral Reefs: A Gallery Program, Grades 7-12.

    ERIC Educational Resources Information Center

    National Aquarium in Baltimore, MD. Dept. of Education.

    Gallery classes at the National Aquarium in Baltimore give the opportunity to study specific aquarium exhibits which demonstrate entire natural habitats. The coral reef gallery class features the gigantic western Atlantic coral reef (325,000 gallons) with over 1,000 fish. The exhibit simulates a typical Caribbean coral reef and nearby sandy

  1. The Experience of External Studies. Occasional Papers No. 4.

    ERIC Educational Resources Information Center

    Riverina Coll. of Advanced Education, Wagga Wagga, New South Wales (Australia).

    This document brings together four invited papers by external students who have graduated from Riverina College: (1) "The External Student: One Profile" (Christine Del Gigante); (2) "Managing Life as a External Student" (Robert Landow); (3) "The Computerised Student" (John Chant); and (4) "The Right to Study" (Coral Davidson). Topics covered

  2. Copyright 2005 by the Genetics Society of America DOI: 10.1534/genetics.104.040121

    E-print Network

    Baillie, David

    extend life span and cause gigantism. We further examined the RNAi phenotypes of the three sets of rpl (rpl-11 and rpl-25), zygotic germ-line function is carried by the autosomal copy. Available RNAi over evolutionary ences therein). In the nematodes, repressing histone time as well. One copy

  3. Introduction The Sun is a mass of incandescent gas

    E-print Network

    Nittler, Larry R.

    and isotopic compositions, we can analyze actual pieces of stars in the laboratory, using mass spectrometersChapter 1 Introduction The Sun is a mass of incandescent gas A gigantic nuclear furnace Building hydrogen into helium At a temperature of millions of degrees They Might be Giants We are stardust Joni

  4. Superdisks in Radio Galaxies Gopal-Krishna

    E-print Network

    Wiita, Paul J.

    Superdisks in Radio Galaxies Gopal-Krishna National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Poona University Campus, Post Bag No. 3, Ganeshkhind, Pune 411 007, India e for a striking new feature of powerful radio galaxies: gigantic disk-like structures of thermal gas and dust

  5. INO/2004/01 Brief Project Report

    E-print Network

    Udgaonkar, Jayant B.

    in neutrino physics and neutrino astronomy. Oscillations of neutrinos and the inferred discovery and collaborators in USA, the gigantic Super-Kamiokande detector in Japan, the heavy-water detector at the Sudbury fundamental way to our knowledge of neutrino properties and interactions. In particular, the Canadian

  6. A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum

    Microsoft Academic Search

    Diego Pol; Alberto Garrido; Ignacio A. Cerda; Andrew Allen Farke

    2011-01-01

    BackgroundThe origin of sauropod dinosaurs is one of the major landmarks of dinosaur evolution but is still poorly understood. This drastic transformation involved major skeletal modifications, including a shift from the small and gracile condition of primitive sauropodomorphs to the gigantic and quadrupedal condition of sauropods. Recent findings in the Late TriassicEarly Jurassic of Gondwana provide critical evidence to understand

  7. Gadsby Gadsby: a story of over 50,000 words without using the letter ...

    E-print Network

    Go to Indo-China and visit its gigantic Ankhor Vat; call at Damascus, Baghdad ...... with arbors, and lots of shrubs that blossom; not just an array of twigs and stalks. ... girls brought in willow twigs, ivy roots, bulbs of canna, dahlia, calladium, tulip,...

  8. The Quaternary vegetation and landscape evolution of Novaya Zemlya in the light of palynological records

    Microsoft Academic Search

    Leonid Serebryanny; Eugeniya Malyasova

    1998-01-01

    The paper presents the results of paleoenvironmental (pollen) investigations of Novaya Zemlya throughout all the Quaternary, including Eopleistocene, Pleistocene and Holocene. Clear evidence of continuity between the modern flora and paleofloras confirms the lack of sharp and continuous interruptions in the vegetation development in high latitudes as well as the absence of gigantic ice sheets in the Eastern Arctic. During

  9. Inferences of Diplodocoid (Sauropoda: Dinosauria) Feeding Behavior from Snout Shape and Microwear Analyses

    Microsoft Academic Search

    John A. Whitlock; Andrew Allen Farke

    2011-01-01

    BackgroundAs gigantic herbivores, sauropod dinosaurs were among the most important members of Mesozoic communities. Understanding their ecology is fundamental to developing a complete picture of Jurassic and Cretaceous food webs. One group of sauropods in particular, Diplodocoidea, has long been a source of debate with regard to what and how they ate. Because of their long lineage duration (Late Jurassic-Late

  10. Riding the Dinosaur Wave.

    ERIC Educational Resources Information Center

    Girod, Mark

    1998-01-01

    As his geology students' specialized knowledge of the Mesozoic era increased, a high school teacher realized he needed a way to showcase their work. The Mesozoic Resource Center's biggest hit was a walk-through diorama showing how life might have been during each of three Mesozoic periods. Highlights included two gigantic student-built dinosaur

  11. This Provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon.

    E-print Network

    Lazzaro, Brian

    host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases represent different environments and reveal one parasite-induced symptom (host castration), which leads

  12. Parasitic castration: a perspective from a model of dynamic energy Spencer R. Hall,1,

    E-print Network

    Hall, Spencer

    Parasitic castration: a perspective from a model of dynamic energy budgets Spencer R. Hall,1, strategy, parasitic castration. Such castration can be accompanied by gigantism (unusually large growth, and enhancing mortality. ``Castrators'' steal energy but also directly modify the scheme by which hosts allocate

  13. The evolution of planktivory in sharks and rays. Supervisor: Dr Charlie Underwood (Birkbeck Earth Sciences)

    E-print Network

    Crawford, Ian

    The evolution of planktivory in sharks and rays. Supervisor: Dr Charlie Underwood (Birkbeck Earth Sciences) Large to gigantic plankton feeding sharks and rays are found throughout the world's oceans with subordinate chondrichthyans (sharks and rays). In contrast, planktivory has evolved several times amongst

  14. Urticria e angiodema associados a fator estimulador das colnias de granulcitos e macrfagos recombinante humano (rhuGM- CSF) em portador de melanoma metasttico* Urticaria and angiodema following subcutaneous injection of recombinant human granulocyte-macrophage colony- stimulating factor (rhuGM-CSF) in a patient with metastatic

    Microsoft Academic Search

    Mario Geller; Priscila Geler Wolff

    2 Resumo: apresentado um caso de melanoma metasttico controlado h seis meses com o fator estimulador das colnias de granulcitos e macrfagos recombinante humano (rhuGM- CSF), administrado periodicamente por via subcutnea. Os autores descrevem, pela primei- ra vez no Brasil, a presena de urticria gigante e angioedema associados a essa bioquimiote- rapia imunoestimulatria, tendo controlado essas reaes adversas com

  15. Scalable electronic packet switches

    Microsoft Academic Search

    Fabio M. Chiussi; Andrea Francini

    2003-01-01

    Due to the changed economic environment, the rush to implementing packet switches with switching capacities above 1 Tb\\/s, which had proceeded at a frantic pace for some years, has slowed down considerably. Most service providers do not foresee the deployment of switches and routers with gigantic capacities in the near future. The immediate interest does now rarely go beyond the

  16. The evolution dynamics of the Strigiformes in the Mediterranean islands with the description of Aegolius martae n. sp. (Aves, Strigidae)

    Microsoft Academic Search

    Marco Pavia

    2008-01-01

    Living and fossil owls (Aves, Strigiformes) constitute an important group for understanding the evolutionary dynamics of birds in island environments. After their different trends in island evolution, the Strigiformes can be seen as a representative of insular adaptations of birds as a whole. In fact they respond quickly to isolation with deep changes in body size, including dwarfism and gigantism,

  17. Shake It up

    ERIC Educational Resources Information Center

    Gilstrap, Tatiana; Sheldon, Peter; Schimmoeller, Peggy

    2010-01-01

    If scientists know where earthquakes are most likely to occur, then architects and engineers can design safer buildings for such areas and potentially prevent some of the devastating aftereffects. Engineers have met this challenge through the design and use of gigantic shake tables to evaluate the stability of various structures. In this 45-minute

  18. A New Text Mining Approach for Finding Protein-to-Disease Associations

    Microsoft Academic Search

    Hisham Al-Mubaid; Rajit K Singh

    2005-01-01

    Discovering significant relationships between biological entities from text documents is an important task for biologists in order to develop biological models for research and discovery, especially with the existing gigantic amounts of biomedical documents and the rate at which they are increasing everyday. We propose a new text mining method to extract associations between biological entities from text documents; and

  19. Not Your Parents' Marching Bands: The History of HONK!, Pedagogy and Music Education

    ERIC Educational Resources Information Center

    Garofalo, Reebee

    2011-01-01

    The HONK! Festival of Activist Street Bands (honkfest.org) is an independent, grassroots, non-commercial weekend festival held each autumn in Somerville, Massachusetts. It is a moving spectacle of colourful marching bands, gigantic puppets, creative bikers, jugglers, hoopers, flag twirlers and stilt walkers, interspersed with unions, activist

  20. Histological studies of the neurosecretory and retrocerebral complex of the water beetle, Hydrophilus olivaceus Fabr. (Insecta, Coleoptera)

    Microsoft Academic Search

    H. S. Gundevia; P. S. Ramamurty

    1972-01-01

    The neurosecretory cells (NSC) in the breeding phases show gigantic sized droplets. NSC show two peaks of activity in females at midnight and at 9 A.M., while a single peak occurs in males between midnight and 3 A.M. Light has a triggering effect on the neurosecretory release. The corpus cardiacum is the main neurohaemal organ. It has a nerve core

  1. Proceedings of ICRC 2001: 703 c Copernicus Gesellschaft 2001 Layout of the Pierre Auger Observatory

    E-print Network

    Observatory A. Etchegoyen1 for the Pierre Auger Observatory Collaboration2 1 Laboratorio Tandar - CNEA, Av conditions on the ex- perimental layout: gigantic in size, hybrid in nature, and one observatory in each hemisphere. Each of the Pierre Auger Observatories extends over an area of 3,000 km2 and com- prise both

  2. Sadness, tragedy and mass disaster in Oklahoma City: providing critical incident stress debriefings to a community in crisis

    Microsoft Academic Search

    J. A. Davis

    1996-01-01

    Shortly after 09:00 h on 19 April 1995, the Alfred P Murrah Federal Building, located in downtown Oklahoma City, was devastated with a bomb blast of such gigantic proportions that it was heard 60 miles away in neighbouring Norman, Oklahoma. Oklahomans routinely commuting to work on that sunny Wednesday morning went about their business as usual. A crude bomb chemically

  3. Primordial Antimatter Plasmas in Our Solar System

    Microsoft Academic Search

    N. Hansen

    2006-01-01

    Summary form only given. Comets have been discovered to be the source of primordial antimatter in our solar system. The announcement was made at April 2002 joint meeting of American Physical Society and American Astronomical Society. When sungrazer comets colliding with the Sun, they produce large sunspots and gigantic solar storms. These enormous ambiplasma storms travel hundreds of millions of

  4. The class material is designed to address fundamental yet extremely interesting questions about earthquakes and plate tectonic activity and their cyclicity. For example: Just why and how are earthquakes generated at plate edges and

    E-print Network

    earthquakes and plate tectonic activity and their cyclicity. For example: Just why and how are earthquakes? Ideas about interactions of the various components of the plate tectonic model and its attendant of crustal deformation produced during complex plate tectonic interactions. Earth is a gigantic heat engine

  5. [Origin of the deep and wide T-wave in myocardial diseases].

    PubMed

    Ostapiuk, F E; Gerchikova, T N

    1977-10-01

    The presented analysis concerns the clinical and electrocardiographic data of dynamic examinations of 15 patients in whom ECG recorded a deep and wide ("gigantic") inverted T-wave. In 5 cases the clinical and electrocardiographic data were compared with the anatomic ones. It was demonstrated that a wide and deep inverted T-wave is common in ischaemic heart disease and inflammatory lesions. Focal myocardial lesions (predominantly in the ventricular septum) combined with atrioventricular conductivity disorders in the His-Purkinje system were found to play a definite role in the genesis of the "gigantic" T-wave. In some cases the wide T-wave may develop due to a fusion of T and U-waves. Patients with such ECG alterations suffer severe rhythm disorders in the form of frequent polytopic extrasystoles, paroxysmal ventricular tachycardia, ventricular fibrillation. PMID:599783

  6. Urano y sus dos satlites irregulares recientemente descubiertos

    NASA Astrophysics Data System (ADS)

    Parisi, M. G.; Brunini, A.

    Hasta hace poco tiempo, Urano era el nico de los Planetas Gigantes que no posea satlites irregulares. Esto lo diferenciaba del resto de los planetas Gigantes, al igual que la peculiar oblicuidad de su eje de spin. La gran inclinacin de su eje de rotacin se debe probablemente a una colisin que sufri el planeta con otro embrin planetario al final del proceso de formacin. Esta colisin habra desligado satlites exteriores preexistentes del planeta. Recientemente se han descubierto dos satlites irregulares de Urano, lo que introduce algunas nuevas cotas y condiciones en el escenario de la "Hiptesis de la Gran Colisin" . Los satlites irregulares de Urano tuvieron que ser capturados en una etapa posterior a la del escenario de la Gran Colisin, de no ser as, 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 satlites irregulares y se presenta un nuevo posible mecanismo para dicha captura.

  7. Treatment of macroglossia in Beckwith-Wiedemann syndrome.

    PubMed

    Clauser, Luigi; Tieghi, Riccardo; Polito, Jessica

    2006-03-01

    A case of macroglossia caused by Beckwith Wiedemann syndrome is reported. Beckwith-Wiedemann Syndrome is an overgrowth disorder characterized by a constellation of congenital anomalies. The most common manifestations are omphalocele, macroglossia, gigantism, and visceromegaly. When the tongue reaches a huge dimension, clinical symptoms are represented by dysphagia, alterations in speech, difficulty in chewing, obstruction of the upper airways, and psychologic consequences derived from the patient's physical appearance. The authors describe the surgical strategy performed in the reported case. PMID:16633192

  8. Apollo Project - Lunar Landing Research Facility

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Aerial view of the Lunar Landing Research Facility under construction. James Hansen noted that '[the facility] was conceived in 1962 by engineer Donald Hewes and built under the careful direction of his quiet but ingenious division chief, W. Hewitt Phillips, this gigantic facility designed to develop techniques for landing the rocket-powered LEM on the moon's surface.' (p. 373) Behind the Facility is the Aircraft Landing Dynamics Facility.

  9. Low-field magnetoelectric effect at room temperature

    Microsoft Academic Search

    Yutaro Kitagawa; Yuji Hiraoka; Takashi Honda; Taishi Ishikura; Hiroyuki Nakamura; Tsuyoshi Kimura

    2010-01-01

    The discoveries of gigantic ferroelectric polarization in BiFeO3 (ref. 1) and ferroelectricity accompanied by a magnetic order in TbMnO3 (ref. 2) have renewed interest in research on magnetoelectric multiferroics, materials in which magnetic and ferroelectric orders coexist, from both fundamental and technological points of view. Among several different types of magnetoelectric multiferroic, magnetically induced ferroelectrics in which ferroelectricity is induced

  10. Electric-field control of spin waves in multiferroic BiFeO3: Theory

    Microsoft Academic Search

    Rogrio de Sousa; P. Rovillain; Y. Gallais; A. Sacuto; M. A. Masson; D. Colson; A. Forget; M. Bibes; A. Barthlmy; M. Cazayous

    2011-01-01

    Our recent experiment [1] demonstrated gigantic (30%) electric-field tuning of magnon frequencies in multiferroic BiFeO3. We demonstrate that the origin of this effect is related to two linear magnetoelectric interactions that couple the component of electric field perpendicular to the ferroelectric vector to a quadratic form of the N'eel vector. We calculate the magnon spectra due to each of these

  11. construyendo dossier de prensa

    E-print Network

    construyendo ciencia 365 días dossier de prensa #12;construyendo ciencia 365 días1. 365 días construyendo ciencia 2. Un gigante en marcha 3.Primera ciencia con GTC 4.Eficiencia en la observación 5. GTC capacidad empresarial, tecnológica y científica para acometer y desarrollar proyectos de "gran ciencia". Se

  12. Magnetoelectric phase control in multiferroic manganites

    Microsoft Academic Search

    Manfred Fiebig

    2006-01-01

    The multiferroic hexagonal RMnO3 compounds with R?=?Sc, Y, In, HoLu are shown to be the source of gigantic magnetoelectric effects: the application of static magnetic or electric field induces a phase transition with antiferromagnetic reordering of the Mn sublattice and ferromagnetic ordering in the rare-earth sublattices. In addition, a coupling of magnetic and electric domain walls is observed.

  13. Chronological overlap between humans and megafauna in Sahul (Pleistocene AustraliaNew Guinea): A review of the evidence

    Microsoft Academic Search

    Judith Field; Melanie Fillios; Stephen Wroe

    2008-01-01

    Over 60 faunal species disappeared from the Australian continent during the MiddleLate Pleistocene. Most of these animals were large to gigantic marsupials, birds and reptiles. A terminal extinction date of 46.4kyr has been proposed for the megafauna, with all sites containing younger fossil megafauna dismissed by some researchers because of questions over stratigraphic integrity or chronologies. The timing of the

  14. Geological and geomorphological precursors of the Chiu-fen-erh-shan landslide triggered by the Chi-chi earthquake in central Taiwan

    Microsoft Academic Search

    Wen-Neng Wang; Masahiro Chigira; Takahiko Furuya

    2003-01-01

    Special features were correlated to the geological causes of the Chiu-fen-erh-shan landslide, a gigantic rockslide on a dip slope, induced by the Chi-chi earthquake (ML=7.3) in central Taiwan in 1999. An aerial photo interpretation and the succeeding geological mapping of the failure were employed in this study. A linear depression, a steep step, and a low drainage density in the

  15. Two-dimensional atomic crystals

    Microsoft Academic Search

    K. S. Novoselov; D. Jiang; F. Schedin; T. J. Booth; V. V. Khotkevich; S. V. Morozov; A. K. Geim

    2005-01-01

    We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D

  16. Arms races and the evolution of big fierce societies.

    PubMed

    Boswell, G P; Franks, N R; Britton, N F

    2001-08-22

    The causes of biological gigantism have received much attention, but only for individual organisms. What selection pressures might favour the evolution of gigantic societies? Here we consider the largest single-queen insect societies, those of the Old World army ant Dorylus, single colonies of which can have 20 million workers. We propose that colony gigantism in Dorylus arises as a result of an arms race and test this prediction by developing a size-structured mathematical model. We use this model for exploring and potentially explaining differences in colony size, colony aggression and colony propagation strategies in populations of New World army ants Eciton and Old World army ants Dorylus. The model shows that, by determining evolutionarily stable strategies (ESSs), differences in the trophic levels at which these army ants live feed forwards into differences in their densities and collision rates and, hence, into different strategies of growth, aggression and propagation. The model predicts large colony size and the occurrence of battles and a colony-propagation strategy involving highly asymmetrical divisions in Dorylus and that Eciton colonies should be smaller, non-combative and exhibit equitable binary fission. These ESSs are in excellent agreement with field observations and demonstrate that gargantuan societies can arise through arms races. PMID:11506686

  17. Discos de acrecin circumplanares: Modelo de Co-acrecin

    NASA Astrophysics Data System (ADS)

    Parisi, M. G.; de Ela, G.

    Los discos de acrecin circumplanetarios precursores de los satlites regulares de los planetas gigantes, se pueden formar por cuatro mecanismos (Pollack y otros, 1991, In Uranus, Bergtralh, Miner y Mattews, Eds., p. 469, Univ. de Arizona Press, Tucson). En este trabajo estudiamos uno de tales mecanismos: el Modelo de Co-acrecin. En dicho modelo, el disco circumplanetario se forma a partir de las colisiones mutuas entre planetesimales dentro de la esfera de Hill del planeta durante el proceso de formacin planetaria. Realizamos un modelo semi-analtico para calcular la masa del disco y compararla con la masa requerida para formar los satlites regulares de los planetas gigantes. Hemos obtenido una cota superior para la masa del disco que resulta inferior a la masa de los satlites ms grandes de los planetas gigantes. En principio, estos resultados permitiran descartar el modelo de co-acrecin como uno de los procesos que podran dar lugar a la formacin de los satlites regulares. Estos resultados permiten obtener restricciones en el escenario de formacin planetaria y en los mecanismos de formacin de sistemas de satlites.

  18. The effect of diet and reproductive maturity on the growth and reproduction of Helisoma anceps (Pulmonata) infected by Halipegus occidualis (Trematoda).

    PubMed

    Keas, B E; Esch, G W

    1997-02-01

    Inhibition of snail reproductive activity by larval trematodes often results in increased growth of the snail, termed gigantism, during which the snail is hypothesized to allocate excess energy normally used for reproduction to somatic growth. Using the planorbid snail Helisoma anceps and the hemiurid trematode Halipegus occidualis, this hypothesis was examined by raising snails on low and high quality diets under 3 infection conditions: uninfected (UNI) and infected prior to (IPR) and after (IAR) reproductive maturity. Snails exhibited gigantism as an increase in wet mass only in the IPR condition on a high quality diet; snails in the IAR condition were not significantly different in size from UNI controls. Throughout the experiment, snails raised on a high quality diet were larger than those on the low quality diet, regardless of infection status, primarily because of increased growth rates prior to the onset of reproduction. Egg production by UNI snails on the high quality diet was 20 times higher than snails on the low diet, even though diet quality only differed by a factor of 4, and infected snails (both IPR and IAR) showed significantly reduced reproductive activity compared to UNI controls. The number of cercariae shed by each snail on a daily basis was not significantly different between IPR and IAR conditions when each diet quality was examined separately; more cercariae were produced by snails raised on the high quality diet. The prevalence of infection at the end of the experiment was lowest among snails raised on the low quality diet, suggesting the diet, i.e., energy intake, influences the loss of infections. Snail mortality did not differ among the various treatment conditions. These data suggest that gigantism is dependent upon snail reproductive maturity at the time of infection and food quality, and comparison to growth rates and fecundity data from previous field studies indicates that H. anceps in the field are probably protein deprived. Gigantism does not appear to be adaptive for the snail because survival was not increased, or for the parasite because cercariae production was the same for snails exhibiting gigantism or not. These results also stress the need for caution when examining the fecundity and growth rates of both uninfected and infected snails in the laboratory, especially when comparing these data to other laboratory or field studies. PMID:9057703

  19. Linear and geometric morphometric analysis of long bone scaling patterns in Jurassic neosauropod dinosaurs: their functional and paleobiological implications.

    PubMed

    Bonnan, Matthew F

    2007-09-01

    Neosauropod dinosaurs were gigantic, herbivorous dinosaurs. Given that the limb skeleton is essentially a plastic, mobile framework that supports and moves the body, analysis of long bone scaling can reveal limb adaptations that supported neosauropod gigantism. Previously, analyses of linear dimensions have revealed a relatively isometric scaling pattern for the humerus and femur of neosauropods. Here, a combined scaling analysis of humerus and femur linear dimensions, cortical area, and shape across six neosauropod taxa is used to test the hypothesis that neosauropod long bones scaled isometrically and to investigate the paleobiological implications of these trends. A combination of linear regression and geometric morphometrics analyses of neosauropod humeri and femora were performed using traditional and thin-plate splines approaches. The neosauropod sample was very homogeneous, and linear analyses revealed that nearly all humerus and femur dimensions, including cortical area, scale with isometry against maximum length. Thin-plate splines analyses showed that little to no significant shape change occurs with increasing length or cortical area for the humerus or femur. Even with the exclusion of the long-limbed Brachiosaurus, the overall trends were consistently isometric. These results suggest that the mechanical advantage of limb-moving muscles and the relative range of limb movement decreased with increasing size. The isometric signal for neosauropod long bone dimensions and shape suggests these dinosaurs may have reached the upper limit of vertebrate long bone mechanics. Perhaps, like stilt-walkers, the absolutely long limbs of the largest neosauropods allowed for efficient locomotion at gigantic size with few ontogenetic changes. PMID:17721981

  20. Nasal encephalocele in a child with Beckwith-Wiedemann syndrome.

    PubMed

    Broekman, Marike L D; Hoving, Eelco W; Kho, Kuan H; Speleman, Lucienne; Han, K Sen; Hanlo, Patrick W

    2008-06-01

    Beckwith-Wiedemann syndrome (BWS) is a rare congenital syndrome characterized by gigantism, macroglossia, exophthalmos, postpartum hypoglycemia, and multiple midline defects such as omphalocele. The authors describe, to the best of their knowledge, the first case of a child in whom BWS was diagnosed and who was subsequently treated for a nasal encephalocele. Because the authors believe that this feature might not be an incidental finding in patients with BWS, intranasal masses in these patients should be carefully differentiated, as complications might be severe. PMID:18518702

  1. The Final Proceedings of the DOE/NASA Solar Power Satellite Program Review

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar power satellite (SPS) concept defined as 'placing gigantic satellites in geosynchronous orbit to capture sunlight, changing the energy into an appropriate form for transmission to Earth, and introducing the energy into the electric power grid' is evaluated in terms of costs and benefits. The concept development and evaluation program is reviewed in four general areas: systems definition; environmental; societal; and comparative assessments. Specific factors addressed include: transportation, construction in space, methods of conversion of sunlight into energy, transmission to Earth, maintenance in orbit and decommissioning of satellites; environmental, political, and economic effects; and comparison of SPS to other forms of power generation, both terrestrial and in space.

  2. Comparison of esterase isoenzyme patterns in seeds of some Allium species and in cultivars of Allium cepa L

    Microsoft Academic Search

    V?ra Hada?ov; Eva Klozov; E. Hada?; V?ra Turkov; Kv?ta Pitterov

    1981-01-01

    Esterase isoenzyme patterns were studied in seeds of 6 cultivars ofAllium cepa L. and of14 species ofAllium, namelyAllium aflatunense B. Fedtsch.,A. altaicum (Pall.) Reyse,A. Cristophii Trautv.,A. fistulosum L.,A. jajlae Vved.,A. Karsianum Fom.,A. nutans L.,A. porrum L. cv. Gigant,A. praemixtum Vved.,A. pskemense Vved.,A. ramosum L.,A.rotundum L.,A. schoenoprasum L.,A. stipitatum Regel. The cultivars differ in their isoenzyme patterns, the cultivar Katick stands

  3. Combined Rastelli and Bentall Procedures for Pulmonary Atresia With Ventricular Septal Defect and a Large Aortopulmonary Collateral Artery and Ascending Aorta Aneurysm.

    PubMed

    Chiostri, Benjamin; Piccinini, Fernando; Vrancic, Mariano; Klinger, Daniel; Navia, Daniel; Lalor, Nicolas; Longo, Francisco; Kreutzer, Christin

    2014-06-23

    We report a challenging case of a 32-year-old patient in New York Heart Association (NYHA) class IV with pulmonary atresia, ventricular septal defect, a left aortopulmonary collateral artery, a right modified Blalock-Taussing shunt, and a gigantic aneurysm of the ascending aorta with severe aortic valve insufficiency. A combined Rastelli and Bentall procedure was performed by a joint adult and pediatric cardiovascular surgery team. One year after the operation, the patient is in NYHA class I, working full time. PMID:24958054

  4. Electric-field control of solitons in a ferroelectric organic charge-transfer salt.

    PubMed

    Kagawa, F; Horiuchi, S; Matsui, H; Kumai, R; Onose, Y; Hasegawa, T; Tokura, Y

    2010-06-01

    The role of solitons in transport, dielectric, and magnetic properties has been revealed for the quasi-one-dimensional organic charge-transfer salt, TTF-QBrCl3 [tetrathiafulvalene (TTF)-2-bromo-3,5,6-trichloro-p-benzoquinone (QBrCl3)]. The material was found to be ferroelectric and hence the solitons should be located at the boundary of the segments with opposite electric polarization. This feature enabled the electric-field control of soliton density and hence the clear-cut detection of soliton contributions. The gigantic dielectric response in the ferroelectric phase is ascribed to the dynamical bound and creeping motions of spinless solitons. PMID:20867204

  5. Microwave Magnetochiral Effect in Cu2OSeO3

    NASA Astrophysics Data System (ADS)

    Mochizuki, Masahito

    2015-05-01

    We theoretically find that in the multiferroic chiral magnet Cu2OSeO3 resonant magnetic excitations are coupled to the collective oscillation of the electric polarization, and thereby attain simultaneous activity to the ac magnetic field and ac electric field. Because of the interference between these magnetic and electric activation processes, this material hosts a gigantic magnetochiral dichroism for microwaves, that is, a directional dichroism at gigahertz frequencies in the Faraday geometry. The absorption intensity of a microwave differs by as much as 30 % depending on whether its propagation direction is parallel or antiparallel to the external magnetic field.

  6. Giant wormlike rubber micelles

    PubMed

    Won; Davis; Bates

    1999-02-12

    A low molecular weight poly(ethyleneoxide)-poly(butadiene) (PEO-PB) diblock copolymer containing 50 weight percent PEO forms gigantic wormlike micelles at low concentrations (<5 percent by weight) in water. Subsequent generation of free radicals with a conventional water-based redox reaction leads to chemical cross-linking of the PB cores without disruption of the cylindrical morphology, as evidenced by cryotransmission electron microscopy and small-angle neutron scattering experiments. These wormlike rubber micelles exhibit unusual viscoelastic properties in water. PMID:9974383

  7. Ar-40 to Ar-39 dating of pseudotachylites from the Witwatersrand basin, South Africa, with implications for the formation of the Vredefort Dome

    NASA Technical Reports Server (NTRS)

    Trieloff, M.; Kunz, J.; Jessberger, E. K.; Reimold, W. U.; Boer, R. H.; Jackson, M. C.

    1992-01-01

    The formation of the Vredefort Dome, a structure in excess of 100 km in diameter and located in the approximate center of the Witwatersrand basin, is still the subject of lively geological controversy. It is widely accepted that its formation seems to have taken place in a single sudden event, herein referred to as the Vredefort event, accompanied by the release of gigantic amounts of energy. It is debated, however, whether this central event was an internal one, i.e., a cryptoexplosion triggered by volcanic or tectonic processes, or the impact of an extraterrestrial body. The results of this debate are presented.

  8. Unified Picture for the Colossal Thermopower Compound FeSb2

    NASA Astrophysics Data System (ADS)

    Battiato, M.; Tomczak, J. M.; Zhong, Z.; Held, K.

    2015-06-01

    We identify the driving mechanism of the gigantic Seebeck coefficient in FeSb2 as the phonon-drag effect associated with an in-gap density of states that we demonstrate to derive from excess iron. We accurately model electronic and thermoelectric transport coefficients and explain the so far ill-understood correlation of maxima and inflection points in different response functions. Our scenario has far-reaching consequences for attempts to harvest the spectacular power factor of FeSb2 .

  9. The accuracy of the ATLAS muon X-ray tomograph

    NASA Astrophysics Data System (ADS)

    Avramidou, R.; Berbiers, J.; Boudineau, C.; Dechelette, C.; Drakoulakos, D.; Fabjan, C.; Grau, S.; Gschwendtner, E.; Maugain, J.-M.; Rieder, H.; Rangod, S.; Rohrbach, F.; Sbrissa, E.; Sedykh, E.; Sedykh, I.; Smirnov, Y.; Vertogradov, L.; Vichou, I.

    2003-01-01

    A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2 ?m systematic and 2 ?m statistical uncertainties in the horizontal and vertical directions in the working area 220 cm (horizontal)60 cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented.

  10. Large meteorite impacts: The K/T model

    NASA Technical Reports Server (NTRS)

    Bohor, B. F.

    1992-01-01

    The Cretaceous/Tertiary (K/T) boundary event represents probably the largest meteorite impact known on Earth. It is the only impact event conclusively linked to a worldwide mass extinction, a reflection of its gigantic scale and global influence. Until recently, the impact crater was not definitively located and only the distal ejecta of this impact was available for study. However, detailed investigations of this ejecta's mineralogy, geochemistry, microstratigraphy, and textures have allowed its modes of ejection and dispersal to be modeled without benefit of a source crater of known size and location.

  11. Theory of magneto-optical effects in helical multiferroic materials via toroidal magnon excitation

    NASA Astrophysics Data System (ADS)

    Miyahara, S.; Furukawa, N.

    2014-05-01

    We investigate dynamical magnetoelectric effect owing to Nambu-Goldstone magnon resonance in helical multiferroic materials. Using the spin wave expansion, we analyzed magneto- and electroactive modes in the J1-J2 Heisenberg model through the spin-current mechanism. Under external magnetic field, the Nambu-Goldstone magnons accompany dynamical toroidal moments, i.e., toroidal magnons, and their resonant absorption shows anomalous features such as nonreciprocal directional dichroism and natural circular dichroism. The estimation indicates that such effects are gigantic in helical magnets.

  12. A Journey Around the World Mind

    E-print Network

    Cambridge University Library; Fox, Peter; Jenkins, Brian

    2010-01-01

    from the fire in Beijing which in 1900 destroyed most of what then remained of the sole surviving copy. These and other rare items, such as the gigantic examination papers from the Chinese civil service, some as big as a babys blanket and which must... custodianship not only gave the Library a certain respectable status in the world of scholarship but also attracted to it donations of books it was too impoverished to buy. But it was, inevitably, to the procuring of Islamic books that Whelock first addressed...

  13. Re-ordering a Border Space: Relief, Rehabilitation, and Nation-Building in North- Eastern India after the 1950 Assam Earthquake

    E-print Network

    Guyot-Rchard, Brnice

    2015-04-08

    to be aseismic.7 Yet if the 1897 disaster was bad enough, the 1950 earthquake was a cataclysm of even greater proportions. At the time, the latter ranked as the fifth biggest tremor ever recorded.8 Newspapers likened it to a gigantic atomic bomb.9... ://earthquake.usgs.gov/earthquakes/world/10_largest_world.php [accessed 18 March 2014]. 9 'Assam earthquake released 1,000,000 times more energy than atom bomb', The Assam Tribune (28 April 1951). 3 come. When these natural dams burst, the water engulfed the countryside, and rivers...

  14. Bursting money bins, the ice and water structure

    NASA Astrophysics Data System (ADS)

    Bagnoli, Franco

    2015-05-01

    In the classic comics by Carl Barks, "The Big Bin on Killmotor Hill" [1], Uncle Scrooge, trying to defend his money bin from the Beagle Boys, follows a suggestion by Donald Duck, and fills the bin with water. Unfortunately, that night is going be the coldest one in the history of Ducksburg. The water freezes, bursting the "ten-foot walls'' of the money bin, and finally the gigantic cube of ice and dollars slips down the hill up to the Beagle Boys lot.

  15. A real-time health monitoring system of offshore platform structure based on fieldbus CAN and OPC

    NASA Astrophysics Data System (ADS)

    He, Lin; Ou, Jinping; Yao, Wei; Tang, Wei

    2005-05-01

    Using control area network (CAN) technique and open connectivity (OPC) method, a sensor fieldbus is developed to acquire and preprocess the data came from structure for monitoring the damage. The OPC interface is added in sensor bus for information sharing. The algorithm of distance of storing-strategy data is embedded in the sensor fieldbus. A system of data acquisition and preprocessing based on the sensor fieldbus is presented and simulated it on the offshore platform. The result shows that the speed and efficiency of sensor fieldbus are reliable and robust when the gigantic data stream into the monitoring system.

  16. Delayed male maturity is a cost of producing large sperm in Drosophila.

    PubMed Central

    Pitnick, S; Markow, T A; Spicer, G S

    1995-01-01

    Among fruit-fly species of the genus Drosophila there is remarkable variation in sperm length, with some species producing gigantic sperm (e.g., > 10 times total male body length). These flies are also unusual in that males of some species exhibit a prolonged adult nonreproductive phase. We document sperm length, body size, and sex-specific ages of reproductive maturity for 42 species of Drosophila and, after controlling for phylogeny, test hypotheses to explain the variation in rates of sexual maturation. Results suggest that delayed male maturity is a cost of producing long sperm. A possible physiological mechanism to explain the observed relationship is discussed. PMID:7479851

  17. Black Smokers

    NSDL National Science Digital Library

    This webpage contains a brief introduction to the discovery of hydrothermal systems and black smokers. Within the webpage are links to information on gigantic tube worms, polychaete worms, oceans, and extreme environments. This site also provides a list of hydrothermal systems, relevant links to organizations, laboratories and observatories, WebQuests, and other websites with further information on hydrothermal systems. As part of the Environmental Literacy Council site, this webpage also contains links to other resources with environmental content, including air climate, land, water, ecosystems, energy, food, and environment and society.

  18. [The virtual reality simulation research of China Mechanical Virtual Human based on the Creator/Vega].

    PubMed

    Wei, Gaofeng; Tang, Gang; Fu, Zengliang; Sun, Qiuming; Tian, Feng

    2010-10-01

    The China Mechanical Virtual Human (CMVH) is a human musculoskeletal biomechanical simulation platform based on China Visible Human slice images; it has great realistic application significance. In this paper is introduced the construction method of CMVH 3D models. Then a simulation system solution based on Creator/Vega is put forward for the complex and gigantic data characteristics of the 3D models. At last, combined with MFC technology, the CMVH simulation system is developed and a running simulation scene is given. This paper provides a new way for the virtual reality application of CMVH. PMID:21089666

  19. Electric-Field Control of Solitons in a Ferroelectric Organic Charge-Transfer Salt

    NASA Astrophysics Data System (ADS)

    Kagawa, F.; Horiuchi, S.; Matsui, H.; Kumai, R.; Onose, Y.; Hasegawa, T.; Tokura, Y.

    2010-06-01

    The role of solitons in transport, dielectric, and magnetic properties has been revealed for the quasi-one-dimensional organic charge-transfer salt, TTF-QBrCl3 [tetrathiafulvalene (TTF)-2-bromo-3,5,6-trichloro-p-benzoquinone (QBrCl3)]. The material was found to be ferroelectric and hence the solitons should be located at the boundary of the segments with opposite electric polarization. This feature enabled the electric-field control of soliton density and hence the clear-cut detection of soliton contributions. The gigantic dielectric response in the ferroelectric phase is ascribed to the dynamical bound and creeping motions of spinless solitons.

  20. Performance Reviews

    E-print Network

    1978-10-01

    opens with a bigger-than-life character called "El Pachuco," who slits open the front pages of the day with his gigantic switch blade. Shortly afterwards, a cardboard character called "The Press" enters to help narrate the action. For those of us who... of native Americans who, it may be, do not often get exposed to theatre. Morton's play went over well with them as it has in other performancesand for much larger numbersin this area. Its flawsmainly, a far too sweeping attempt to cover vast spans...

  1. WUArchive: File Archive at Washington University in St. Louis

    NSDL National Science Digital Library

    The gigantic and very popular FTP archive at Washington University at St. Louis (wuarchive) is available as a Web site, providing easy access for those who don't remember how to spell anonymous. Over 65 gigabytes of files in 11 top level directories (with literally hundreds of directories underneath) covering such topics as systems, graphics, documentation, selected Usenet News archives, and educational programs and materials. New is a list of the hundreds of sites wuarchive mirrors. Concentration is on computer related items, however see the public directory for an eclectic selection of files.

  2. Two-dimensional atomic crystals.

    PubMed

    Novoselov, K S; Jiang, D; Schedin, F; Booth, T J; Khotkevich, V V; Morozov, S V; Geim, A K

    2005-07-26

    We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale. PMID:16027370

  3. Two-dimensional atomic crystals

    PubMed Central

    Novoselov, K. S.; Jiang, D.; Schedin, F.; Booth, T. J.; Khotkevich, V. V.; Morozov, S. V.; Geim, A. K.

    2005-01-01

    We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale. PMID:16027370

  4. Well-being and excellence in the Earth sciences

    NASA Astrophysics Data System (ADS)

    Drake, Charles L.

    In the symposium on Earth Sciences and Society at the Spring AGU Meeting May 29-June 1, Baltimore, Md.), I was assigned to speak on the maintenance of excellence and national well-being in the Earth sciences. I developed serious writer's block every time I approached the topic until I remembered a paragraph at the beginning of Doug Adams' great text, The Restaurant at the End of the Universe [Adams, 1982]. It tells how [A race of highly intelligent pan-dimensional beings once built themselves a gigantic supercomputer called Deep Thought to calculate once and for all the Answer to the Ultimate Question of Life, Universe and Everything. For seven and a half million years, Deep Thought computed and calculated, and in the end announced that the answer was in fact Forty-twoand so another, even bigger, computer had to be built to find out what the actual question was. And this computer, which was called the Earth, was so large that it was frequently mistaken for a planet-especially by the strange apelike beings who roamed its surface, totally unaware that they were simply part of a gigantic computer program. And this is very odd, because without that fairly simple and obvious piece of knowledge, nothing that ever happened on the Earth could possibly make the slightest bit of sense.

  5. Genomic comparison of closely related Giant Viruses supports an accordion-like model of evolution

    PubMed Central

    File, Jonathan

    2015-01-01

    Genome gigantism occurs so far in Phycodnaviridae and Mimiviridae (order Megavirales). Origin and evolution of these Giant Viruses (GVs) remain open questions. Interestingly, availability of a collection of closely related GV genomes enabling genomic comparisons offer the opportunity to better understand the different evolutionary forces acting on these genomes. Whole genome alignment for five groups of viruses belonging to the Mimiviridae and Phycodnaviridae families show that there is no trend of genome expansion or general tendency of genome contraction. Instead, GV genomes accumulated genomic mutations over the time with gene gains compensating the different losses. In addition, each lineage displays specific patterns of genome evolution. Mimiviridae (megaviruses and mimiviruses) and Chlorella Phycodnaviruses evolved mainly by duplications and losses of genes belonging to large paralogous families (including movements of diverse mobiles genetic elements), whereas Micromonas and Ostreococcus Phycodnaviruses derive most of their genetic novelties thought lateral gene transfers. Taken together, these data support an accordion-like model of evolution in which GV genomes have undergone successive steps of gene gain and gene loss, accrediting the hypothesis that genome gigantism appears early, before the diversification of the different GV lineages.

  6. The cosmic origin of supersymmetry and internal symmetry

    E-print Network

    Ding-Yu Chung

    2001-02-06

    The cosmic vacuum is the wavefunction of the eleven dimensional Planck supermembrane. The Planck wavefunction is the superposition of dimensions from eleven to four dimensional spacetime with decreasing energy and increasing size. The cosmic vacuum is a gigantic cosmic particle-wave. It undergoes a gigantic slow cosmic oscillation between the high-energy eleven dimensional spacetime and the low-energy four dimensional spacetime. The origin of ordinary (baryonic) matter in the big bang universe is the collapsed Planck wavefunction due to the lepton-quark entangled state with two unequal sets of spacetime as the quantum system-measurement entangled state in Hilbert space. The collapsed Planck wavefunction has four dimensional spacetime and seven dimensional internal space (non-spacetime) with seven gauge bosons. The remnants of the cosmic oscillation are cosmic radiation, gravity, and microscopic particle-wave in the four dimensional spacetime. Internal symmetries for gauge bosons, leptons, quarks, and black holes are in the seven dimensional internal space. The result is the big bang universe with the cosmic vacuum. The cosmic vacuum has the four-to-eleven dimensional spacetime supersymmetry, while the big bang universe has the four dimensional spacetime and the seven dimensional internal space. The masses of elementary particles can be calculated with only four known constants: the number of the extra spatial dimensions in the supermembrane, the mass of electron, the mass of Z, and the fine structure constant for the magnetic field.

  7. Chromosome evolution with naked eye: Palindromic context of the life origin

    NASA Astrophysics Data System (ADS)

    Larionov, Sergei; Loskutov, Alexander; Ryadchenko, Eugeny

    2008-03-01

    Based on the representation of the DNA sequence as a two-dimensional (2D) plane walk, we consider the problem of identification and comparison of functional and structural organizations of chromosomes of different organisms. According to the characteristic design of 2D walks we identify telomere sites, palindromes of various sizes and complexity, areas of ribosomal RNA, transposons, as well as diverse satellite sequences. As an interesting result of the application of the 2D walk method, a new duplicated gigantic palindrome in the X human chromosome is detected. A schematic mechanism leading to the formation of such a duplicated palindrome is proposed. Analysis of a large number of the different genomes shows that some chromosomes (or their fragments) of various species appear as imperfect gigantic palindromes, which are disintegrated by many inversions and the mutation drift on different scales. A spread occurrence of these types of sequences in the numerous chromosomes allows us to develop a new insight of some accepted points of the genome evolution in the prebiotic phase.

  8. Development of high purity large forgings for nuclear power plants

    NASA Astrophysics Data System (ADS)

    Tanaka, Yasuhiko; Sato, Ikuo

    2011-10-01

    The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

  9. Mechanism of enhanced optical second-harmonic generation in the conducting pyrochlore-type Pb2Ir2O7-x oxide compound.

    PubMed

    Hirata, Yasuyuki; Nakajima, Makoto; Nomura, Yusuke; Tajima, Hiroyuki; Matsushita, Yoshitaka; Asoh, Keiko; Kiuchi, Yoko; Eguiluz, Adolfo G; Arita, Ryotaro; Suemoto, Tohru; Ohgushi, Kenya

    2013-05-01

    The structural, electronic, and optical properties of pyrochlore-type Pb(2)Ir(2)O(6)O(0.55)('), which is a metal without spatial inversion symmetry at room temperature, were investigated. Structural analysis revealed that the structural distortion relevant to the breakdown of the inversion symmetry is dominated by the Pb-O' network but is very small in the Ir-O network. At the same time, gigantic second-harmonic generation signals were observed, which can only occur if the local environment of the Ir 5d electrons features broken inversion symmetry. First-principles electronic structure calculations reveal that the underlying mechanism for this phenomenon is the induction of the noncentrosymmetricity in the Ir 5d bands by the strong hybridization with O' 2p orbitals. Our results stimulate theoretical study of inversion-broken iridates, where exotic quantum states such as a topological insulator and Dirac semimetal are anticipated. PMID:23683242

  10. Anesthetic management of two cases of Beckwith-Wiedemann syndrome.

    PubMed

    Kimura, Yoshinobu; Kamada, Yasuhiro; Kimura, Saori

    2008-01-01

    Two cases of children with Beckwith-Wiedemann syndrome are presented. This syndrome consists of various abnormalities, including macroglossia, visceromegaly, omphalocele, and gigantism. These abnormalities frequently require operative correction during the neonatal period. We anesthesiologists should make plans for difficult airway managements in patients with this syndrome. Our two patients also showed larger sized tracheas than those estimated by their age and height. A cuffed tube, though still controversial, has recently been used in children. We recommend using a cuffed tube in patients with this syndrome, because the appropriate tracheal size may not be predictable, tracheal intubation might be difficult, and risks incurred during changing of a tracheal tube should be avoided. PMID:18306025

  11. A Graph Summarization Algorithm Based on RFID Logistics

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Hu, Kongfa; Lu, Zhipeng; Zhao, Li; Chen, Ling

    Radio Frequency Identification (RFID) applications are set to play an essential role in object tracking and supply chain management systems. The volume of data generated by a typical RFID application will be enormous as each item will generate a complete history of all the individual locations that it occupied at every point in time. The movement trails of such RFID data form gigantic commodity flowgraph representing the locations and durations of the path stages traversed by each item. In this paper, we use graph to construct a warehouse of RFID commodity flows, and introduce a database-style operation to summarize graphs, which produces a summary graph by grouping nodes based on user-selected node attributes, further allows users to control the hierarchy of summaries. It can cut down the size of graphs, and provide convenience for users to study just on the shrunk graph which they interested. Through extensive experiments, we demonstrate the effectiveness and efficiency of the proposed method.

  12. Monster of the Milky Way

    NSDL National Science Digital Library

    This NOVA television broadcast discusses black holes and presents new research indicating that a supermassive black hole may lurk at the center of our own galaxy. Features include interviews with researchers who explain the basics of black holes and reveal why they think the Milky Way may harbor a gigantic black hole at its center, and audio clips of physicists and astronomers describing their ideas about black holes. A slide show explains the process by which particularly massive stars consume their nuclear fuel, explode in a supernova, and collapse to an unimaginably dense point called a singularity. There is also a program preview and transcript, as well as an interactive catalog of other astronomical objects.

  13. A giant ornithomimosaur from the Early Cretaceous of China.

    PubMed

    Makovicky, Peter J; Li, Daqing; Gao, Ke-Qin; Lewin, Matthew; Erickson, Gregory M; Norell, Mark A

    2010-01-22

    Ornithomimosaurs (ostrich-mimic dinosaurs) are a common element of some Cretaceous dinosaur assemblages of Asia and North America. Here, we describe a new species of ornithomimosaur, Beishanlong grandis, from an associated, partial postcranial skeleton from the Aptian-Albian Xinminpu Group of northern Gansu, China. Beishanlong is similar to another Aptian-Albian ornithomimosaur, Harpymimus, with which it shares a phylogenetic position as more derived than the Barremian Shenzhousaurus and as sister to a Late Cretaceous clade composed of Garudimimus and the Ornithomimidae. Beishanlong is one of the largest definitive ornithomimosaurs yet described, though histological analysis shows that the holotype individual was still growing at its death. Together with the co-eval and sympatric therizinosaur Suzhousaurus and the oviraptorosaur Gigantraptor, Beishanlong provides evidence for the parallel evolution of gigantism in separate lineages of beaked and possibly herbivorous coelurosaurs within a short time span in Central Asia. PMID:19386658

  14. Petroleum, alcohol, and energy substitution in Brazil: Theoretical and empirical issues

    SciTech Connect

    Biller, D.

    1991-01-01

    As in other Latin American nations, the petroleum industry has always been surrounded by controversy in Brazil. Issues related to exploration, exploitation, and import of crude have received special attention by Brazilian decision makers. In the past decade, an additional relevant issue was brought into play by the oil crisis. An import substitution program for energy was implemented by the development of alternative indigenous energy sources. Among these sources, sugarcane was viewed as a reliable renewable resource for the production of fuel alcohol and, very recently, of electricity. Brazil engaged in a gigantic program of fuel substitution, which is now facing severe problems due to the fall of petroleum prices. This study analyzes the recent energy import substitution program in Brazil, specifically concentrating on microeconomic and environmental aspects of fuel substitution.

  15. Mainland size variation informs predictive models of exceptional insular body size change in rodents.

    PubMed

    Durst, Paul A P; Roth, V Louise

    2015-07-01

    The tendency for island populations of mammalian taxa to diverge in body size from their mainland counterparts consistently in particular directions is both impressive for its regularity and, especially among rodents, troublesome for its exceptions. However, previous studies have largely ignored mainland body size variation, treating size differences of any magnitude as equally noteworthy. Here, we use distributions of mainland population body sizes to identify island populations as 'extremely' big or small, and we compare traits of extreme populations and their islands with those of island populations more typical in body size. We find that although insular rodents vary in the directions of body size change, 'extreme' populations tend towards gigantism. With classification tree methods, we develop a predictive model, which points to resource limitations as major drivers in the few cases of insular dwarfism. Highly successful in classifying our dataset, our model also successfully predicts change in untested cases. PMID:26085585

  16. Bilateral renal dysplasia, nephroblastomatosis, and bronchial stenosis. A new syndrome?

    PubMed

    Rodriguez, Maria Matilde; Correa-Medina, Mayrin; Whittington, Elizabeth E

    2015-06-01

    Bilateral nephroblastomatosis (NB) is an uncommon renal anomaly characterized by multiple confluent nephrogenic rests scattered through both kidneys, with only a limited number of cases reported in the medical literature. Some of these children may have associated either Perlman or Beckwith-Wiedemann syndrome and others do not demonstrate syndromic features. We report a full-term boy with anteverted nose, bilateral bronchial stenosis due to lack of cartilage, bilateral obstructive renal dysplasia and NB with glomeruloid features. The infant had visceromegaly, but neither gigantism nor hemihypertrophy. Immunohistochemistry for PAX2 (Paired box gene-2) and WT-1 (Wilms Tumor 1) were strongly positive in the areas of NB. GLEPP-1 (Glomerular Epithelial Protein) did not stain the areas of NB with a glomeruloid appearance, but was positive in the renal glomeruli as expected. We found neither associated bronchial stenosis nor the histology of NB resembling giant glomeruli in any of the reported cases of NB. PMID:25871299

  17. Eating and digesting "Lestrygonians": a physiological model of reading.

    PubMed

    Yared, Aida

    2008-01-01

    In this article, I propose that, beneath a deceptively simple story-line, "Lestrygonians" functions like a living entity, one through which Bloom unknowingly traverses. First, there is Joyce's familiar Dublin, on a macroscopic level, and, second, there is the episode's narrative, personified by a gigantic female organism, in whose digestive tract Bloom has been reduced to Lilliputian size. Some critics have noted the importance of the physiological details of digestion here; no one, however, has noted to what extent the structure of the episode is represented by the digestive model. My final claim about the episode's digestive proclivities concerns its effects on the reader. If "Lestrygonians" replicates alimentary functions by propelling both its characters and the reading process along, it also elicits, in the reader, the synesthesia of reading with autonomic sensations. PMID:20836271

  18. Lying down with protective setae as an alternative antipredator defence in a non-webbing spider mite.

    PubMed

    Yano, Shuichi; Shirotsuka, Kanako

    2013-01-01

    An antipredator defence in the citrus red mite Panonychus citri, which does not produce protective webs, was examined experimentally. P. citri adult females lie down on citrus leaf surfaces with their dorsal setae (hair) directed in all upper directions. They seldom move in response to physical stimuli. Compared to normal lying females, both manipulated non-lying females and hair-removed females suffered higher predation by predatory mites. A predator approaching the body surface of a lying female inevitably created elasticity with a confronting seta, which eventually repelled the predator away from the female. These observations indicated that lying down with protective setae functions as an antipredator defence in P. citri females. This inflexible defence could also explain why the mite rarely runs away, even when it is consumed together with host plant leaves (via coincidental intraguild predation) by gigantic swallowtail caterpillars, against which protective setae are totally ineffective. PMID:24312748

  19. The Financial Policy of William Pitt, 1784-1802

    E-print Network

    Warkentin, John Henry

    1908-01-01

    The Commercial Treaty w i t h Prance Opposition E f f e c t on the Trade of England The C o n s o l i d a t i o n of Duties The Abuses i n the P o s t a l System The Shop tax The Income tax C r i t i c i s m on P i t t ' s Scheme Taxation E n g l i s h... l skeleton of a gigantic trade,important f o r the reason that customs duties and excise formed the l a r g e r portion of the m i n i s t e r s revenue. For the sake of getting a better understanding of the other taxes one or two have been...

  20. MoMA: The Changing of the Avant-Garde

    NSDL National Science Digital Library

    2002-01-01

    This Web exhibition from MoMA presents a history of modern utopian and visionary architecture, using architectural drawings donated to the museum by the Howard Gilman Foundation in 2000. The drawings date from the late 1950s to the 1970s. The main menu is two spheres, Megastructures (larger, public buildings and complexes) and Postmodern Roots (smaller buildings, retail and houses), from which users can select names to view particular projects. Each project consists of two to four drawings and explanatory text, with larger views of all the drawings available. An interesting example under Megastructures is Superstudio, a group of five Italian architects who, in the 1960s, created a set of purely theoretical drawing that impose gigantic, white, grid-patterned structures on natural landscapes such as rivers, ocean coastlines, and the Alps. Megastructures give way to Postmodern Roots in the 1960s, where drawings of projects by Robert Venturi, Michael Graves, James Stirling, Rem Koolhaas, and others can be seen.

  1. Saramago's All the Names and the epidemiological dream.

    PubMed

    Almeida-Filho, Naomar

    2004-09-01

    Language is crucial for all established scientific disciplines in contemporary society, particularly epidemiology. Portuguese writer Saramago wrote All the Names, a book about the Conservatria, a gigantic registry that stores the whole life of an entire population. A parallel is made with the first social observatories that used entire populations for systematic observation, permitting the development of epidemiological methodology. Such "epidemiological dream" almost became true in virtual form with the introduction of electronic data processing. The central thesis of this paper is that Saramago's Conservatria allegory might be interpreted as akin to the virtual world construed by epidemiological science. Specifically, it is about abstract realities (or theoretical environments) that by definition are necessary for the process of scientific inquiry, particularly when oriented by knowledge production through observational strategies. Reading Saramago, the epidemiological virtualscape may be envisaged, more imaginary than it is usual to imagine and more real than it is usual to realise. PMID:15310798

  2. The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina.

    PubMed

    Chatterjee, Sankar; Templin, R Jack; Campbell, Kenneth E

    2007-07-24

    We calculate the flight performance of the gigantic volant bird Argentavis magnificens from the upper Miocene ( approximately 6 million years ago) of Argentina using a computer simulation model. Argentavis was probably too large (mass approximately 70 kg) to be capable of continuous flapping flight or standing takeoff under its own muscle power. Like extant condors and vultures, Argentavis would have extracted energy from the atmosphere for flight, relying on thermals present on the Argentinean pampas to provide power for soaring, and it probably used slope soaring over the windward slopes of the Andes. It was an excellent glider, with a gliding angle close to 3 degrees and a cruising speed of 67 kph. Argentavis could take off by running downhill, or by launching from a perch to pick up flight speed. Other means of takeoff remain problematic. PMID:17609382

  3. Magnetic Biasing of a Ferroelectric Hysteresis Loop in a Multiferroic Orthoferrite

    NASA Astrophysics Data System (ADS)

    Tokunaga, Y.; Taguchi, Y.; Arima, T.; Tokura, Y.

    2014-01-01

    In a multiferroic orthoferrite Dy0.7Tb0.3FeO3, which shows electric-field-(E-)driven magnetization (M) reversal due to a tight clamping between polarization (P) and M, a gigantic effect of magnetic-field (H) biasing on P-E hysteresis loops is observed in the case of rapid E sweeping. The magnitude of the bias E field can be controlled by varying the magnitude of H, and its sign can be reversed by changing the sign of H or the relative clamping direction between P and M. The origin of this unconventional biasing effect is ascribed to the difference in the Zeeman energy between the +P and -P states coupled with the M states with opposite sign.

  4. [Relationship between disaster stress and peptic ulcers].

    PubMed

    Kanno, Takeshi; Iijima, Katsunori; Koike, Tomoyuki; Shimosegawa, Tooru

    2015-07-01

    There had been several reports about the increasing of peptic ulcers under a large-scale disaster or a war. But in human, it was still unclear that a severe psychological stress itself cause peptic ulcer independently of two major causes (Helicobacter pylori infection and nonsteroidal anti-inflammatory drugs). After Great East Japan earthquake in March 11th, 2011, one of the five most powerful earthquakes in the world since modern record keeping began in 1900, we also noticed remarkable increasing of patients with peptic ulcer in wide stricken area. Reports after this gigantic earthquake gave us two new important viewpoints. Disaster (psychological) stress possibly induce peptic ulcer independently of two major causes. And, people living in refugee shelter immediately after a disaster are strong risk group of peptic ulcer bleeding as well as an intake of anti-thrombotic agents. PMID:26165082

  5. A clinically novel AIP mutation in a patient with a very large, apparently sporadic somatotrope adenoma

    PubMed Central

    Daly, Adrian F; Quinones-Hinojosa, Alfredo; Thiry, Albert; Beckers, Albert

    2014-01-01

    Summary Heterozygous germline inactivating mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene lead to pituitary adenomas that most frequently present in the setting of familial isolated pituitary adenoma syndrome, usually as somatotropinomas and prolactinomas. More recently, they have been found in a significant percentage of young patients presenting with pituitary macroadenoma without any apparent family history. We describe the case of a 19-year-old man who presented with a gigantic somatotropinoma. His family history was negative. His peripheral DNA showed a heterozygous AIP mutation (p.I13N), while tumor tissue only had the mutated allele, showing loss of heterozygosity (LOH) and suggesting that the mutation caused the disease. Learning points AIP mutations may be observed in sporadic somatotrope adenomas occurring in young patients.LOH is a strong indicator that an AIP variant is disease causing.Somatotrope adenomas in carriers of AIP mutations are generally larger and more difficult to cure. PMID:25136448

  6. A basal dromaeosaurid and size evolution preceding avian flight.

    PubMed

    Turner, Alan H; Pol, Diego; Clarke, Julia A; Erickson, Gregory M; Norell, Mark A

    2007-09-01

    Fossil evidence for changes in dinosaurs near the lineage leading to birds and the origin of flight has been sparse. A dinosaur from Mongolia represents the basal divergence within Dromaeosauridae. The taxon's small body size and phylogenetic position imply that extreme miniaturization was ancestral for Paraves (the clade including Avialae, Troodontidae, and Dromaeosauridae), phylogenetically earlier than where flight evolution is strongly inferred. In contrast to the sustained small body sizes among avialans throughout the Cretaceous Period, the two dinosaurian lineages most closely related to birds, dromaeosaurids and troodontids, underwent four independent events of gigantism, and in some lineages size increased by nearly three orders of magnitude. Thus, change in theropod body size leading to flight's origin was not unidirectional. PMID:17823350

  7. Turnaround in Cyclic Cosmology

    SciTech Connect

    Baum, Lauris; Frampton, Paul H. [University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)

    2007-02-16

    It is speculated how dark energy in a brane world can help reconcile an infinitely cyclic cosmology with the second law of thermodynamics. A cyclic model is described, in which dark energy with w<-1 equation of state leads to a turnaround at a time, extremely shortly before the would-be big rip, at which both volume and entropy of our Universe decrease by a gigantic factor, while very many independent similarly small contracting universes are spawned. The entropy of our model decreases almost to zero at turnaround but increases for the remainder of the cycle by a vanishingly small amount during contraction, empty of matter, then by a large factor during inflationary expansion.

  8. Turnaround in cyclic cosmology.

    PubMed

    Baum, Lauris; Frampton, Paul H

    2007-02-16

    It is speculated how dark energy in a brane world can help reconcile an infinitely cyclic cosmology with the second law of thermodynamics. A cyclic model is described, in which dark energy with w<-1 equation of state leads to a turnaround at a time, extremely shortly before the would-be big rip, at which both volume and entropy of our Universe decrease by a gigantic factor, while very many independent similarly small contracting universes are spawned. The entropy of our model decreases almost to zero at turnaround but increases for the remainder of the cycle by a vanishingly small amount during contraction, empty of matter, then by a large factor during inflationary expansion. PMID:17359014

  9. Saddlebags, Paperbacks and Mobile Media

    NASA Astrophysics Data System (ADS)

    Zwick, Carola

    Information is shaped by its format. The printing press with its repeatable layout laid ground for footnotes and references from other sources, and thus can be seen as the technology that initially generated the concept of hyperlinks. In the fifteenth century, printed matter quickly developed other formats like the paperback book or the flyer. These formats changed the content in almost every aspect significantly: books that fit in a saddlebag are mobile media and thus not as precious as the gigantic and prestigious folio placed on a lectern stand in a monastery. So books became a widespread, "ordinary" mobile medium and developed a multitude of purposes, aimed at different audiences, and generated a wide range of ideas for adequate content. The flyer in its limited size and public nature generated other forms of organizing and designing content: in order to fit the format and draw attention it uses a condensed form of messaging and an exaggerated typography.

  10. How can you sail in outer space?

    NSDL National Science Digital Library

    Twin Cities Public Television

    2004-01-01

    Can a spaceship save on fuel by sailing in space? This riddle asks students how such a feat could be accomplished. A paragraph and video clip on a clue page sum up two girls' investigation into one possible solution. The girls knew that air is absent in space, so they set out to see if a fan would move a sail in a vacuum chamber. When students select the correct answer from the riddle's three answer choices, a brief video plays that describes how sunlight can exert enough force to propel spacecraft equipped with solar sails (thin, gigantic mirrors). The video explains why this technique can work in space but not on Earth. A text version of the riddle is available.

  11. Giant spiral shaped spermatozoa of Diasemopsis comoroensis (Diptera, Diopsidae) with a unique ultrastructural component.

    PubMed

    Kotrba, M; He, M

    2013-12-01

    In this study we describe a new kind of sperm gigantism in the stalk-eyed fly, Diasemopsis comoroensis (Diptera, Diopsidae). The sperm cells have a length of up to 1.7 mm and can be coiled into a compact 'slinky' spiral. Their ultrastructure involves a prominent electron dense central band, which runs the entire length of the sperm tail and in some regions constitutes its largest element in cross section. We propose that this organelle is either a giant centriole adjunct or a kind of accessory body derived from it, and that it takes part in coiling the sperm tail. To our knowledge, no comparable structure has been described before. PMID:24054968

  12. 7. View of interior of Lock No. 2 on George ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. View of interior of Lock No. 2 on George washington 'Potowmack' Canal at Great Falls, Virginia. This lock is about 15 ft. in depth and possibly 70 or 60 ft. in length. Some 15 or 20 years ago, when a restoration was crudely attempted, the old oaken flooring, which was invariably placed at the bottom of canal locks, was roughly torn up and destroyed. The trunks and stumps of gigantic trees still remain from this restorative effort, and their girth indicates again the antiquity of this evidence of George Washington's work as an engineer. The stones are of the red Seneca type and were evidently ferried from the Maryland side above the dam and then brought by sled or rollers to this location. These stones were beautifully hand-cut and fitted with ... - Potowmack Company: Great Falls Canal, Lock No. 2, Great Falls, Fairfax County, VA

  13. ?Li-loaded directionally sensitive anti-neutrino detector for possible geo-neutrinographic imaging applications.

    PubMed

    Tanaka, H K M; Watanabe, H

    2014-01-01

    Despite the latent and unique benefits of imaging uranium and thorium's distribution in the earth's interior, previously proposed experimental techniques used to identify the incoming geo-neutrino's direction are not applicable to practical imaging due to the high miss-identification in a neutrino's track reconstruction. After performing experimental studies and Monte-Carlo simulations, we confirmed that a significant improvement is possible in neutrino tracking identification with a (6)Li-loaded neutrino detector. For possible imaging applications, we also explore the feasibility of producing geo-neutrinographic images of gigantic magmatic reservoirs and deep structure in the mantle. We anticipate and plan to apply these newly designed detectors to radiographic imaging of the Earth's interior, monitoring of nuclear reactors, and tracking astrophysical sources of neutrinos. PMID:24759616

  14. Brazilian distribution of Amblyomma varium Koch, 1844 (Acari: Ixodidae), a common parasite of sloths (Mammalia: Xenarthra).

    PubMed

    Marques, Sandro; Barros-Battesti, Darci Moraes; Faccini, Joo Luiz Horacio; Onofrio, Valeria Castilho

    2002-12-01

    Amblyomma varium, commonly known in Brazil as the "carrapato-gigante-da-pregui a" (sloth's giant tick) is found from southern Central America to Argentina. The present study adds information on the geographical distribution of A. varium, as well as on their hosts, based on material deposited in the main Brazilian collections and on the available literature. Eighty-two vials, containing 191 adult specimens, deposited in five Acari collections between 1930 and 2001, were examined. These vials included data on the host and collection localities. The biology of A. varium is unknown. However it is known that, during the adult stage, the tick presents a high host specificity and is found almost exclusively on the sloths Bradypus tridactylus, B. variegatus, B.torquatus (Bradypodidae), Choloepus hoffmanni and C. didactylus (Megalonychidae). Based on the material examined, the states of Rond nia, Amazonas, Bahia and Alagoas are newly assigned to geographic distribution of A. varium in Brazil. PMID:12563481

  15. The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina

    PubMed Central

    Chatterjee, Sankar; Templin, R. Jack; Campbell, Kenneth E.

    2007-01-01

    We calculate the flight performance of the gigantic volant bird Argentavis magnificens from the upper Miocene (?6 million years ago) of Argentina using a computer simulation model. Argentavis was probably too large (mass ?70 kg) to be capable of continuous flapping flight or standing takeoff under its own muscle power. Like extant condors and vultures, Argentavis would have extracted energy from the atmosphere for flight, relying on thermals present on the Argentinean pampas to provide power for soaring, and it probably used slope soaring over the windward slopes of the Andes. It was an excellent glider, with a gliding angle close to 3 and a cruising speed of 67 kph. Argentavis could take off by running downhill, or by launching from a perch to pick up flight speed. Other means of takeoff remain problematic. PMID:17609382

  16. Raising the sauropod neck: it costs more to get less

    PubMed Central

    Seymour, Roger S.

    2009-01-01

    The long necks of gigantic sauropod dinosaurs are commonly assumed to have been used for high browsing to obtain enough food. However, this analysis questions whether such a posture was reasonable from the standpoint of energetics. The energy cost of circulating the blood can be estimated accurately from two physiological axioms that relate metabolic rate, blood flow rate and arterial blood pressure: (i) metabolic rate is proportional to blood flow rate and (ii) cardiac work rate is proportional to the product of blood flow rate and blood pressure. The analysis shows that it would have required the animal to expend approximately half of its energy intake just to circulate the blood, primarily because a vertical neck would have required a high systemic arterial blood pressure. It is therefore energetically more feasible to have used a more or less horizontal neck to enable wide browsing while keeping blood pressure low. PMID:19364714

  17. Lead in ancient Rome's city waters.

    PubMed

    Delile, Hugo; Blichert-Toft, Janne; Goiran, Jean-Philippe; Keay, Simon; Albarde, Francis

    2014-05-01

    It is now universally accepted that utilization of lead for domestic purposes and water distribution presents a major health hazard. The ancient Roman world was unaware of these risks. How far the gigantic network of lead pipes used in ancient Rome compromised public health in the city is unknown. Lead isotopes in sediments from the harbor of Imperial Rome register the presence of a strong anthropogenic component during the beginning of the Common Era and the Early Middle Ages. They demonstrate that the lead pipes of the water distribution system increased Pb contents in drinking water of the capital city by up to two orders of magnitude over the natural background. The Pb isotope record shows that the discontinuities in the pollution of the Tiber by lead are intimately entwined with the major issues affecting Late Antique Rome and its water distribution system. PMID:24753588

  18. Magnetic biasing of a ferroelectric hysteresis loop in a multiferroic orthoferrite.

    PubMed

    Tokunaga, Y; Taguchi, Y; Arima, T; Tokura, Y

    2014-01-24

    In a multiferroic orthoferrite Dy0.7Tb0.3FeO3, which shows electric-field-(E-)driven magnetization (M) reversal due to a tight clamping between polarization (P) and M, a gigantic effect of magnetic-field (H) biasing on P-E hysteresis loops is observed in the case of rapid E sweeping. The magnitude of the bias E field can be controlled by varying the magnitude of H, and its sign can be reversed by changing the sign of H or the relative clamping direction between P and M. The origin of this unconventional biasing effect is ascribed to the difference in the Zeeman energy between the +P and -P states coupled with the M states with opposite sign. PMID:24484164

  19. Woods: A fast and accurate functional annotator and classifier of genomic and metagenomic sequences.

    PubMed

    Sharma, Ashok K; Gupta, Ankit; Kumar, Sanjiv; Dhakan, Darshan B; Sharma, Vineet K

    2015-07-01

    Functional annotation of the gigantic metagenomic data is one of the major time-consuming and computationally demanding tasks, which is currently a bottleneck for the efficient analysis. The commonly used homology-based methods to functionally annotate and classify proteins are extremely slow. Therefore, to achieve faster and accurate functional annotation, we have developed an orthology-based functional classifier 'Woods' by using a combination of machine learning and similarity-based approaches. Woods displayed a precision of 98.79% on independent genomic dataset, 96.66% on simulated metagenomic dataset and >97% on two real metagenomic datasets. In addition, it performed >87 times faster than BLAST on the two real metagenomic datasets. Woods can be used as a highly efficient and accurate classifier with high-throughput capability which facilitates its usability on large metagenomic datasets. PMID:25863333

  20. 6Li-loaded directionally sensitive anti-neutrino detector for possible geo-neutrinographic imaging applications

    PubMed Central

    Tanaka, H. K. M.; Watanabe, H.

    2014-01-01

    Despite the latent and unique benefits of imaging uranium and thorium's distribution in the earth's interior, previously proposed experimental techniques used to identify the incoming geo-neutrino's direction are not applicable to practical imaging due to the high miss-identification in a neutrino's track reconstruction. After performing experimental studies and Monte-Carlo simulations, we confirmed that a significant improvement is possible in neutrino tracking identification with a 6Li-loaded neutrino detector. For possible imaging applications, we also explore the feasibility of producing geo-neutrinographic images of gigantic magmatic reservoirs and deep structure in the mantle. We anticipate and plan to apply these newly designed detectors to radiographic imaging of the Earth's interior, monitoring of nuclear reactors, and tracking astrophysical sources of neutrinos. PMID:24759616

  1. On the fate of pumice rafts formed during the 2012 Havre submarine eruption.

    PubMed

    Jutzeler, Martin; Marsh, Robert; Carey, Rebecca J; White, James D L; Talling, Peter J; Karlstrom, Leif

    2014-01-01

    Pumice rafts are floating mobile accumulations of low-density pumice clasts generated by silicic volcanic eruptions. Pumice in rafts can drift for years, become waterlogged and sink, or become stranded on shorelines. Here we show that the pumice raft formed by the impressive, deep submarine eruption of the Havre caldera volcano (Southwest Pacific) in July 2012 can be mapped by satellite imagery augmented by sailing crew observations. Far from coastal interference, the eruption produced a single >400 km(2) raft in 1 day, thus initiating a gigantic, high-precision, natural experiment relevant to both modern and prehistoric oceanic surface dispersal dynamics. Observed raft dispersal can be accurately reproduced by simulating drift and dispersal patterns using currents from an eddy-resolving ocean model hindcast. For future eruptions that produce potentially hazardous pumice rafts, our technique allows real-time forecasts of dispersal routes, in addition to inference of ash/pumice deposit distribution in the deep ocean. PMID:24755668

  2. Impact of Parallel Computing on Large Scale Aeroelastic Computations

    NASA Technical Reports Server (NTRS)

    Guruswamy, Guru P.; Kwak, Dochan (Technical Monitor)

    2000-01-01

    Aeroelasticity is computationally one of the most intensive fields in aerospace engineering. Though over the last three decades the computational speed of supercomputers have substantially increased, they are still inadequate for large scale aeroelastic computations using high fidelity flow and structural equations. In addition to reaching a saturation in computational speed because of changes in economics, computer manufactures are stopping the manufacturing of mainframe type supercomputers. This has led computational aeroelasticians to face the gigantic task of finding alternate approaches for fulfilling their needs. The alternate path to over come speed and availability limitations of mainframe type supercomputers is to use parallel computers. During this decade several different architectures have evolved. In FY92 the US Government started the High Performance Computing and Communication (HPCC) program. As a participant in this program NASA developed several parallel computational tools for aeroelastic applications. This talk describes the impact of those application tools on high fidelity based multidisciplinary analysis.

  3. Parity Violation in Astrophysics

    E-print Network

    C. J. Horowitz

    2004-10-17

    Core collapse supernovae are gigantic explosions of massive stars that radiate 99% of their energy in neutrinos. This provides a unique opportunity for large scale parity or charge conjugation violation. Parity violation in a strong magnetic field could lead to an asymmetry in the neutrino radiation and recoil of the newly formed neutron star. Charge conjugation violation in the neutrino-nucleon interaction reduces the ratio of neutrons to protons in the neutrino driven wind above the neutron star. This is a problem for r-process nucleosynthesis in this wind. On earth, parity violation is an excellent probe of neutrons because the weak charge of a neutron is much larger than that of a proton. The Parity Radius Experiment (PREX) at Jefferson Laboratory aims to precisely measure the neutron radius of $^{208}$Pb with parity violating elastic electron scattering. This has many implications for astrophysics, including the structure of neutron stars, and for atomic parity nonconservation experiments.}

  4. Surgical Treatment of an Immature Short-Rooted Traumatized Incisor with an Extensive Apical Lesion Using CEM Cement.

    PubMed

    Asgary, Saeed; Fazlyab, Mahta

    2015-01-01

    Severe traumatic injuries to immature teeth often cause damage to periodontal ligament as well as dental pulp; pulp necrosis, root resorption and subsequent apical lesion are common consequences. This article reports the surgical management of an infected immature maxillary central incisor associated with a gigantic periradicular lesion and severe root resorption. The tooth had a history of trauma and the patient suffered from purulent sinus tract and tooth mobility. After unsuccessful multi-session disinfection with calcium hydroxide, root end surgery was planned. During flap surgery and lesion enucleation, the root end was cleaned and filled with calcium-enriched mixture (CEM) cement. After one year, the radiographic examination revealed that the lesion was almost completely replaced with newly formed bone. In addition, clinical examination showed favorable outcomes; the tooth was symptom-free and in function. Due to chemical, physical and biological properties of CEM cement, this biomaterial might be considered as the root-end filling material of choice. PMID:25834603

  5. UV and IR quantum-spacetime effects for the Chandrasekhar model

    E-print Network

    Giovanni Amelino-Camelia; Niccolo' Loret; Gianluca Mandanici; Flavio Mercati

    2011-10-24

    We modify the Chandrasekhar model of white dwarfs by introducing novel momentum-space features that characterize the analysis of some quantum-spacetime scenarios. We find that the rather standard ultraviolet effects of spacetime quantization can only be significant in a regime where the Chandrasekhar model anyway lacks any contact with observations. But a new class of quantum-spacetime effects inspired by the mechanism of "ultraviolet/infrared mixing" could be relevant for white dwarfs whose mass is roughly half the mass of the Sun, some of which are described in the literature as "strange white dwarfs". We also offer a preliminary argument suggesting that Planck-scale (ultraviolet) effects could be significant in cases where ultra-high densities are present, even when the relevant star is still gigantic in Planck-length units.

  6. From paper drawings to computer-aided design

    NASA Astrophysics Data System (ADS)

    Karima, M.; Sadhal, K. S.; McNeil, T. O.

    1985-02-01

    The benefits of a fully integrated computer-aided design and drafting system (CADDS) database are today very well accepted by industry, and major engineering companies implementing CADDS are confronted with the gigantic task of entering the existing multidisciplinary engineering information into the CADDS database. The present investigation is concerned with the findings of a feasibility study which had been conducted by a Canadian company to explore data capture on engineering drawings. A review of the state of the art in digitization is presented, and attention is given to specific problems arising in the case of the Canadian company. It is found that substantial advancements have been made toward the automatic 'reading' of existing drawings on paper media. However, no system exists currently which fully automates the data capturing process in the engineering environment and generates intelligent databases for use by CADD systems. Suitable approaches for 'data capture' under the given conditions are discussed.

  7. Cloud Formation and Water Transport on Mars after Major Outflow Events

    NASA Technical Reports Server (NTRS)

    Santiago, D. L.; Colaprete, A.; Kreslavsky, M.; Kahre, M. A.; Asphaug, E.

    2012-01-01

    The triggering of a robust water cycle on Mars might have been caused by the gigantic flooding events evidenced by outflow channels. We use the Ames Mars General Circulation Model (MGCM) to test this hypothesis, studying how these presumably abrupt eruptions of water might have affected the climate of Mars in the past. We model where the water ultimately went as part of a transient atmospheric water cycle, to answer questions including: (1) Can sudden introductions of large amounts of water on the Martian surface lead to a new equilibrated water cycle? (2) What are the roles of water vapor and water ice clouds to sudden changes in the water cycle on Mars? (3) How are radiative feedbacks involved with this? (4) What is the ultimate fate of the outflow water? (5) Can we tie certain geological features to outflow water redistributed by the atmosphere?

  8. The Discharge Characteristics of TLE-Producing Lightning

    NASA Astrophysics Data System (ADS)

    Chang, S. C.; Huang, S. M.; Kuo, C. L.; Lee, L. J.; Chou, J. K.; Wu, Y. J.; Chen, A. B.; Su, H. T.; Hsu, R. R.; Lee, L. C.

    2013-09-01

    On 2 August 2010 and from a site located at the southern tip of Taiwan, we observed 51 TLEs over a thunderstorm near Luzon Island which featured abundant negative cloud-to-ground (-CG) lightning. The TLE events include 42 negative elves, 7 negative halos, 3 positive sprites, and 1 negative cloud-toionosphere (-CI; TYPE I) gigantic jet. The ULF and VLF band sferics of these TLEs were also recorded by radio stations in Taiwan. The radio waveforms of the TLE-associated lightning discharges appear to show dependence on the type of TLEs. For example, the ratio of the peak magnetic field in ULF and VLF bands appear to vary with the type of TLEs. Also based on the observed sferics, we try to find the discharge waveform for the lightning that will induce TLEs.

  9. Dinosaur body temperatures determined from isotopic (C-?O) ordering in fossil biominerals.

    PubMed

    Eagle, Robert A; Ttken, Thomas; Martin, Taylor S; Tripati, Aradhna K; Fricke, Henry C; Connely, Melissa; Cifelli, Richard L; Eiler, John M

    2011-07-22

    The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms on the basis of differing methodologies. We used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36 to 38C, which are similar to those of most modern mammals. This temperature range is 4 to 7C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached because of their gigantic size. PMID:21700837

  10. On the fate of pumice rafts formed during the 2012 Havre submarine eruption

    PubMed Central

    Jutzeler, Martin; Marsh, Robert; Carey, Rebecca J.; White, James D. L.; Talling, Peter J.; Karlstrom, Leif

    2014-01-01

    Pumice rafts are floating mobile accumulations of low-density pumice clasts generated by silicic volcanic eruptions. Pumice in rafts can drift for years, become waterlogged and sink, or become stranded on shorelines. Here we show that the pumice raft formed by the impressive, deep submarine eruption of the Havre caldera volcano (Southwest Pacific) in July 2012 can be mapped by satellite imagery augmented by sailing crew observations. Far from coastal interference, the eruption produced a single >400?km2 raft in 1 day, thus initiating a gigantic, high-precision, natural experiment relevant to both modern and prehistoric oceanic surface dispersal dynamics. Observed raft dispersal can be accurately reproduced by simulating drift and dispersal patterns using currents from an eddy-resolving ocean model hindcast. For future eruptions that produce potentially hazardous pumice rafts, our technique allows real-time forecasts of dispersal routes, in addition to inference of ash/pumice deposit distribution in the deep ocean. PMID:24755668

  11. Physical characteristics of TLEs inferred from ISUAL observations (Invited)

    NASA Astrophysics Data System (ADS)

    Kuo, C.; Chen, A. B.; Su, H.; Hsu, R.; Frey, H. U.; Mende, S. B.; Takahashi, Y.; Lee, L.

    2010-12-01

    ISUAL/FORMOSAT-2 is the first satellite mission for the long term survey of upper atmospheric transient luminous phenomena/events (TLEs). The payload consists of three sensor packages including an intensified CCD imager, a six-channel spectrophotometer and a dual-band array photometer. Hence ISUAL experiment could provide information to understand the spatial and the temporal evolutions of TLEs. In this presentation, we will review the important findings of the ISUAL mission in the first five years of operation; mainly on the electric field of sprites streamers [Pasko, 2004; Kuo et al., 2005; Liu et al., 2006; Adachi et al., 2006; Liu et al, 2010; Celestin and Pasko, 2010], the FUV emissions of elves [Mende et al., 2005; Chang et al., 2010], the luminous and electric properties of gigantic jets [Su et al., 2005; Kuo et al., 2009; Chou et al., 2010], and the high-altitude sprite current and the lightning continuing current [Cummer et al, 2006; Adachi et al, 2009]. ISUAL has carried out 762 nm-filtered, 557.7 nm-filtered and 427.8 nm-filtered imager campaigns, besides the regular 1PN2 emission survey. For the 762 nm-filtered imager campaign, a weak but detectable O2 Atmospheric band emission (~1 kR) was predicted based on a plasma chemistry model [Sentman et al., 2008], and the image data may have confirmed the existence of this band emission. While, no significant 557.7 nm emissions were detected from the ISUAL recorded elves. In the 427.8 nm campaign, altitudinal ionization profile of sprites was inferred. The ionization structure of elves and the leader structure of gigantic jets will also be discussed.

  12. On the Formation of the Dabashan Orocline, Central China: Evidence from Seismic Ambient Noise Tomography

    NASA Astrophysics Data System (ADS)

    Jiang, C.; Yang, Y.; Zheng, Y.

    2014-12-01

    The gigantic Dabashan orocline, situated in the south Qinling Orogen, is a response of the tectonic uplift to the collision between the North China Craton and the Yangtze Craton in Mesozoic. However, how the orocline formed and deformed is still not well understood mainly due to inaccessible deep crust structures. In this study, we aim to address this question by investigating the detailed crust structures. We process continuous ambient noise data collected from ~170 stations of Chinese provincial networks operating during 2007 and 2009 to extract interstation surface wave dispersion curves. Using these dispersion curves, we generate Rayleigh wave phase velocity maps at 6-60 sec periods. By inverting the resulting Rayleigh wave dispersion maps using a Bayesian Monte Carlo method, we construct a 3D isotropic Vsv model with a lateral resolution of 50-60 km. The 3D Vsv model reveals detailed crust velocity structures which help to decipher the formation mechanism of the Dabashan orocline. Prominent low velocities are observed beneath the Dabashan orocline at 10-15 km depth, which may represent the buried passive continental margin sedimentations of the Yangtze Craton. High velocities are observed on the two sides of the orocline beneath the Shengnongjia-Huangling and Hannan Domes extending from the surface with Archean-aged outcrops to the mid/lower crust. The deep-rooted high-velocity domes very likely reflect the presence of the relative rigid Archean basement which acts as obstacles during the intra-continental shortening; while detachments may develop in the weak passive continental margin of sedimentations beneath the Dabashan during the shortening process, assisting the southward thrusting of nappes from the south Qinling Orogen onto the northern margin of the Yangtze Craton, which finally forms the gigantic Dabashan orocline. This model is also consistent with the thermo-chronological constraints and stratigraphic records which together indicate the initiation of the uplifts in the two domes are possibly earlier than in Dabashan.

  13. Is IGSF1 involved in human pituitary tumor formation?

    PubMed

    Faucz, Fabio R; Horvath, Anelia D; Azevedo, Monalisa F; Levy, Isaac; Bak, Beata; Wang, Ying; Xekouki, Paraskevi; Szarek, Eva; Gourgari, Evgenia; Manning, Allison D; de Alexandre, Rodrigo Bertollo; Saloustros, Emmanouil; Trivellin, Giampaolo; Lodish, Maya; Hofman, Paul; Anderson, Yvonne C; Holdaway, Ian; Oldfield, Edward; Chittiboina, Prashant; Nesterova, Maria; Biermasz, Nienke R; Wit, Jan M; Bernard, Daniel J; Stratakis, Constantine A

    2015-02-01

    IGSF1 is a membrane glycoprotein highly expressed in the anterior pituitary. Pathogenic mutations in the IGSF1 gene (on Xq26.2) are associated with X-linked central hypothyroidism and testicular enlargement in males. In this study, we tested the hypothesis that IGSF1 is involved in the development of pituitary tumors, especially those that produce growth hormone (GH). IGSF1 was sequenced in 21 patients with gigantism or acromegaly and 92 healthy individuals. Expression studies with a candidate pathogenic IGSF1 variant were carried out in transfected cells and immunohistochemistry for IGSF1 was performed in the sections of GH-producing adenomas, familial somatomammotroph hyperplasia, and in normal pituitary. We identified the sequence variant p.N604T, which in silico analysis suggested could affect IGSF1 function, in two male patients and one female with somatomammotroph hyperplasia from the same family. Of 60 female controls, two carried the same variant and seven were heterozygous for other variants. Immunohistochemistry showed increased IGSF1 staining in the GH-producing tumor from the patient with the IGSF1 p.N604T variant compared with a GH-producing adenoma from a patient negative for any IGSF1 variants and with normal control pituitary tissue. The IGSF1 gene appears polymorphic in the general population. A potentially pathogenic variant identified in the germline of three patients with gigantism from the same family (segregating with the disease) was also detected in two healthy female controls. Variations in IGSF1 expression in pituitary tissue in patients with or without IGSF1 germline mutations point to the need for further studies of IGSF1 action in pituitary adenoma formation. PMID:25527509

  14. Lightning channels emerging from the top of thunderstorm clouds

    NASA Astrophysics Data System (ADS)

    van der Velde, Oscar; Montany, Joan; Soula, Serge; Pineda, Nicolau

    2013-04-01

    In recent years, research of transient luminous events is shifting from the rather common elves and sprites high above thunderclouds to the much less frequently observed phenomena issued by the storm cloud itself: gigantic jets (GJ) connecting to the ionosphere, and high-energy terrestrial gamma-ray flashes (TGFs) recorded at spacecraft. These phenomena both are observed more often at tropical latitudes, and a link may or may not exist between the two. It is likely that both share the requirement of high-altitude leaders of negative polarity, which in the case of a GJ escapes from the cloud top and transforms into a long streamer discharge. While this should be easier at lower air densities (higher altitude), previous studies showed that GJs need not be produced by storms with the highest tops. TGFs have still unclear origins, but may be related to production in negative leaders or other regions with strong vertically directed electric fields by runaway electron mechnisms. In December 2009, a gigantic jet was observed in the Mediterranean Sea region. During the same night, a nearby storm produced repeatedly multiple leaders piercing through the cloud top, without any sign of streamers reaching higher altitudes (unlike jets or starters). Similar observations of upward cloud-to-air lightning have been obtained recently by low-light cameras over storms near the Catalonian coast in different seasons. The production conditions are currently being investigated, with a focus on optically determined altitudes of lightning and evolution of storm tops (and their temperature level). The initial impression is that cloud flashes escape into the air above during stages when the growing convective cloud top is very close to the main charge production region. Upward cloud-to-air lightning has also been mapped by the Ebro Lightning Mapping Array, exhibiting inverse bolt-from-the blue characteristics, and as a by-product of a bolt-from-the-blue lightning strike to ground, recorded by a high-speed camera.

  15. Rheological profile of the Tohoku-oki interplate megathrust across the source region of the M9 great earthquake

    NASA Astrophysics Data System (ADS)

    Shimizu, I.

    2013-12-01

    Before attacked by the 2011 Tohoku-oki Earthquake (M9.0), large earthquakes off the Pacific coast of NE Japan had been believed to occur at specific areas, named asperities, on the subducting plate interface. In the NE Japan subduction zone, a typical asperity was found offshore of Miyagi Prefecture (Miyagi-oki), where M7-class earthquakes occurred in 1936, 1978, and 2005, with recurrence intervals of 37 years. However, the M9 gigantic earthquake occurred at the up-dip side of the asperity of the M7-class Miyagi-oki earthquakes. The large slips at the M9 event have been differently explained by different numerical models due to the lack of our knowledge on frictional properties and stress states at the plate interface. Here we constrain the stress states on the NE Japan interplate megathrust from a viewpoint of rock rheology. A strength profile of the megathrust was constructed across the source region of the M9 Tohoku-oki earthquake using laboratory data of friction, fracturing and ductile flow. Rheological properties of siliceous sedimentary rocks and subducting seamounts at the top of the oceanic plate were represented by those of wet quartz and gabbro, respectively. Depth-dependent changes of pressure, temperature, and pore pressure ratio were incorporated into the model. The frictional strength of the thrust fault was estimated to be about 150 MPa at the hypocenter of the M9 earthquake, which is located 17-18 km below the sea level. The large coseismic slips observed at the M9 event are explained by the large difference in fault strength between the shallow tsunami-genic zone and the M9 hypocentral zone. A large stress drop induced by a collapse of a subducted seamount possibly triggered the gigantic earthquake. At the deep (>35 km) part of the thrust fault, where M7-class Miyagi-oki earthquakes repeatedly occurred, siliceous rocks become ductile whereas gabbroic rocks are brittle and strong. Thus, the asperity of the M7-class earthquakes is considered as a broken seamount, which is surrounded by siliceous sedimentary rocks. A conditionally stable nature of the surrounding region is explained by frictional behaviors of quartz in the brittle-ductile transition zone. In contrast to the deep M7-class asperity, the M9 asperity (i.e., a region that was strongly coupled before the M9 Tohoku-oki earthquake) occupies a large part of the plate interface because shear strength is relatively insensitive to rock types at the intermediate depth. The along-arc extension of the M9 asperity is possibly constrained by fluid distributions on the plate interface.

  16. The Geometric Characteristics and Initiation Mechanisms of the Earthquake- Triggered Daguangbao Landslide

    NASA Astrophysics Data System (ADS)

    Dong, J. J.; Tsao, C. C.; Yang, C. M.; Wu, W. J.; Lee, C. T.; Lin, M. L.; Zhang, W. F.; Pei, X. J.; Wang, G. H.; Huang, R.

    2014-12-01

    Recently, catastrophic landslides are getting considerable attentions not only from natural hazard but also from geo-material science. In the past century, the Daguangbao (DGB) landslide which triggered by the Wenchuan earthquake is one of the largest earthquake- triggered landslides. Our main goal is to characterize the geometry of DGB landslide to better determine the initiation mechanisms. Based on the remote sensing images analysis and field investigation, we proposed an atypical wedge model of DGB landslide compose of a folded strata and a zigzag stepping-out joint system, which outcropped at the south and north of the landslide site, respectively. The intersection line of wedge is curved, counterclockwise rotated and daylighted, which fit the pre- and post- position of the mining tent with 1.9 km displacements. The volume of sliding mass was evaluated to 10.51108 m3 by the atypical wedge model. The identified slip zone of DGB landslide consists of the breccia and gouge layers in the dolomite strata. The rotary-shear tests were performed with the intact dolomite rocks near the slip zone and the gouges in the slip zone to determine the strength of slip surface. The peak and the steady-state friction coefficient of the tested dry dolomite discontinuities, wet gouges are 0.52~0.96, 0.73~0.86 and 0.1~0.57, 0.16~0.63, respectively. Although the result of static wedge stability analysis shows that the slope is quite stable (F.S. = 4), but the result of pseudo-static wedge stability analysis with seismic coefficient will trigger the gigantic wedge by the Wenchuan earthquake. Moreover, the friction coefficient of the tested gouges after long slip displacements as shear velocity exceeds 1.3 m/s will lower than 0.25 (=tan(14); the intersection line plunged 14). Therefore, the gigantic wedge can be accelerated by the inertial force and keep moving rapidly with long run-out. According to the calculations of simple one dimensional particle motion model, DGB landslide traveled 52~68 seconds with a maximum velocity of 58~75 m/sec.

  17. Analysis of impulse signals with Hylaty ELF station

    NASA Astrophysics Data System (ADS)

    Kulak, A.; Mlynarczyk, J.; Ostrowski, M.; Kubisz, J.; Michalec, A.

    2012-04-01

    Lighting discharges generate electromagnetic field pulses that propagate in the Earth-ionosphere waveguide. The attenuation in the ELF range is so small that the pulses originating from strong atmospheric discharges can be observed even several thousand kilometers away from the individual discharge. The recorded waveform depends on the discharge process, the Earth-ionosphere waveguide properties on the source-receiver path, and the transfer function of the receiver. If the distance from the source is known, an inverse method can be used for reconstructing the current moment waveform and the charge moment of the discharge. In order to reconstruct the source parameters from the recorded signal a reliable model of the radio wave propagation in the Earth-ionosphere waveguide as well as practical signal processing techniques are necessary. We present two methods, both based on analytical formulas. The first method allows for fast calculation of the charge moment of relatively short atmospheric discharges. It is based on peak amplitude measurement of the recorded magnetic component of the ELF EM field and it takes into account the receiver characteristics. The second method, called "inverse channel method" allows reconstructing the complete current moment waveform of strong atmospheric discharges that exhibit the continuing current phase, such as Gigantic Jets and Sprites. The method makes it possible to fully remove from the observed waveform the distortions related to the receiver's impulse response as well as the influence of the Earth-ionosphere propagation channel. Our ELF station is equipped with two magnetic antennas for Bx and By components measurement in the 0.03 to 55 Hz frequency range. ELF Data recording is carried out since 1993, with continuous data acquisition since 2005. The station features low noise level and precise timing. It is battery powered and located in the sparsely populated area, far from major electric power lines, which results in high quality signal recordings and allows for precise calculations of the charge moments of upward discharges and strong cloud-to-ground discharges originating from distant sources. The same data is used for Schumann resonance observation. We demonstrate the use of our methods based on recent recordings from the Hylaty ELF station. We include examples of GJ (Gigantic Jet) and TGF (Terrestrial Gamma-ray Flash) related discharges.

  18. Electron energy distribution functions and transport coefficients relevant for air plasmas in the troposphere: impact of humidity and gas temperature

    NASA Astrophysics Data System (ADS)

    Gordillo-Vzquez, F. J.; Donk, Z.

    2009-08-01

    A Boltzmann and Monte Carlo analysis of the electron energy distribution function (EEDF) and transport coefficients for air plasmas is presented for the conditions of the Earth troposphere where some transient luminous events (TLEs) such as blue jets, blue starters and gigantic jets have been observed. According to recent model results (Minschwaner et al 2004 J. Climate 17 1272) supported by the halogen occultation experiment, the relative humidity of the atmospheric air between 0 and 15 km can change between 15% and 100% depending on the altitude investigated and the ground temperature. The latter results cover a region of latitudes between -25S and +25N, that is, the Earth tropical region where lightning and TLE activity is quite high. The calculations shown here suggest that the relative humidity has a clear impact on the behaviour of the EEDF and magnitude of the transport coefficients of air plasmas at ground (0 km) and room temperature conditions (293 K). At higher altitudes (11 and 15 km), the influence of the relative humidity is negligible when the values of the gas temperature are assumed to be the 'natural' ones corresponding to those altitudes, that is, ~215 K (at 11 km) and ~198 K (at 15 km). However, it is found that a small enhancement (of maximum 100 K) in the background gas temperature (that could be reasonably associated with the TLE activity) would lead to a remarkable impact of the relative humidity on the EEDF and transport coefficients of air plasmas under the conditions of blue jets, blue starters and gigantic jets at 11 and 15 km. The latter effects are visible for relatively low reduced electric fields (E/N <= 25 Td) that could be controlling the afterglow kinetics of the air plasmas generated by TLEs. However, for much higher fields such as, for instance, 400 Td (representative of the fields in the streamer coronas and lightning leaders), the impact of increasing the relative humidity and gas temperature is only slightly noticeable in the attachment coefficient that can exhibit an increase of up to one order of magnitude at 11 km and 15 km for temperatures of 313 K and 308 K, respectively. Finally, a brief analysis is carried out on the impact of the gas temperature on the diffusion coefficients of neutrals and ions. The present results show quite reasonable agreement with available measurements in dry and moist air.

  19. The kinematics and initiation mechanisms of the earthquake-triggered Daguangbao landslide

    NASA Astrophysics Data System (ADS)

    Yang, Che-Ming; Cheng, Hui-Yun; Tsao, Chia-Che; Wu, Wen-Jie; Dong, Jia-Jyun; Lee, Chyi-Tyi; Lin, Ming-Lang; Zhang, Wei-Fong; Pei, Xiang-Jun; Wang, Gong-Hui; Huang, Run-Qiu

    2015-04-01

    The Daguangbao (DGB) landslide is one of the largest earthquake-triggered landslides induced by the 2008 Wenchuan earthquake in the world over the past century. Based on remote sensing images, topography analysis and field investigation, this landslide was speculated a gigantic atypical wedge failure with the folded bedding plane and a zigzag stepping-out joint system, which outcropped at the south and north, respectively. With the inferred failure surfaces, the volume of the DGB landslide is about 1,051 Mm3. The frequently adopted Rigid Wedge Method (RWM), which assumed zero shear stress on the sliding surface along the vectors perpendicular to the intersection line when evaluating the wedge stability, could not be valid for this super large DGB wedge. Under an assumption that the shear strength is fully mobilized on the sliding surface along the vectors perpendicular to the intersection line, this study proposed to use a Maximum Shear Stress Method (MSSM) to calculate the factor of safety (FOS) of the DGB wedge. Based on the assumptions of the two methods, the FOS of the RWM and MSSM are the upper and lower bounds for the wedge stability analysis. Based on the rotary shear tests, the averaged friction coefficients of the representative materials of the two sliding surfaces are 0.79 (bedding parallel fault gauges) and 0.71 (dolomite joints). Without external force, the FOSs of the DGB landslide are 4.14 and 2.51 by the RWM and MSSM, respectively. Restate, the wedge is stable before the 2008 Wenchuan earthquake. However, DGB landslide can be triggered at 35.7 sec based on the ground acceleration records of strong motion station MZQP during the 2008 Wenchuan earthquake and the pseudo-static stability analysis incorporated into MSSM (Acceleration: EW=0.272g, NS=0.152g, Vertical=0.244g). Moreover, using the friction coefficient of the representative materials under large shear displacement under shear velocity of 1.3 m/s (0.16 for bedding parallel fault gouges and 0.1 for dolomite joints), the gigantic wedge can be speeded up to a maximum velocity of 54 m/sec. The traveled time will be 70 seconds with a travel distance of 1.9 km.

  20. The Interstellar Medium in the Small Magellanic Cloud: Results from MCELS

    NASA Astrophysics Data System (ADS)

    Winkler, P. F.; Smith, R. C.; Points, S. D.; MCELS Team

    2015-05-01

    The interstellar medium (ISM) provides the playing field where gas and dust are cycled into and out of stars through dynamic and complex interactions, including H II regions, planetary nebulae, supernovae and their remnants, superbubbles, and gigantic supershells. The relative proximity and low extinction make the Large and Small Magellanic Clouds ideal venues for studying the ISM: its constituents, energetics, and interaction with the underlying stellar populations. The Magellanic Cloud Emission Line Survey (MCELS) surveyed both the LMC and SMC over six years using the Curtis Schmidt Telescope at CTIO to produce deep images in H?, [S II] and [O III] lines, plus matched red and green continuum bands for star subtraction. The survey covers the central 88 degrees of the LMC and 4.5 3.5 degrees of the SMCmost of the gaseous extent of both galaxiesat a resolution of 5? or better. This enables us to identify and study structures on scales ranging from 1 pc to global. In this paper we highlight some of the results from MCELS, concentrating on the SMC. These include deep inventories of PNe and SNRs, analysis of H II regions and their optical depth, and extended structures on the scale of the entire galaxy. We also include some brief historical anecdotes.

  1. Anomalous surface lattice dynamics in the low-temperature phase of Ba(Fe1?xCox)2As2

    PubMed Central

    Teng, Jing; Chen, Chen; Xiong, Yimin; Zhang, Jiandi; Jin, Rongying; Plummer, E. W.

    2013-01-01

    In complex materials, how correlation between charge, spin, and lattice affects the emergent phenomena remains unclear. The newly discovered iron-based high-temperature superconductors and related compounds present to the community a prototype family of materials, where interplay between charge, spin, and lattice degrees of freedom can be explored. With the occurrence of structural, magnetic, and superconducting transitions in the bulk of these materials, creating a surface will change the delicate balance between these phases, resulting in new behavior. A surface lattice dynamics study on (001) Ba(Fe1?xCox)2As2, through electron energy loss spectroscopy measurements, reveals unusual temperature dependence of both the phonon frequency and line width in the low-temperature orthorhombic phase. The rate of change of phonon frequency with temperature is gigantic, two orders of magnitude larger than in the bulk. This behavior cannot be explained using conventional models of anharmonicity or electronphonon coupling; instead, it requires that a large surface-spin-charge-lattice coupling be included. Furthermore, the higher surface-phase-transition temperature driven by surface stabilization of the low-temperature orthorhombic phase seems to turn the first-order transition (bulk) into the second-order type, equivalent to what is observed in the bulk by applying a uniaxial pressure. Such equivalence indicates that the surface mirrors the bulk under extreme conditions. PMID:23284168

  2. Thermal Expansion Anomaly Regulated by Entropy

    NASA Astrophysics Data System (ADS)

    Liu, Zi-Kui; Wang, Yi; Shang, Shunli

    2014-11-01

    Thermal expansion, defined as the temperature dependence of volume under constant pressure, is a common phenomenon in nature and originates from anharmonic lattice dynamics. However, it has been poorly understood how thermal expansion can show anomalies such as colossal positive, zero, or negative thermal expansion (CPTE, ZTE, or NTE), especially in quantitative terms. Here we show that changes in configurational entropy due to metastable micro(scopic)states can lead to quantitative prediction of these anomalies. We integrate the Maxwell relation, statistic mechanics, and first-principles calculations to demonstrate that when the entropy is increased by pressure, NTE occurs such as in Invar alloy (Fe3Pt, for example), silicon, ice, and water, and when the entropy is decreased dramatically by pressure, CPTE is expected such as in anti-Invar cerium, ice and water. Our findings provide a theoretic framework to understand and predict a broad range of anomalies in nature in addition to thermal expansion, which may include gigantic electrocaloric and electromechanical responses, anomalously reduced thermal conductivity, and spin distributions.

  3. Thermal expansion anomaly regulated by entropy.

    PubMed

    Liu, Zi-Kui; Wang, Yi; Shang, ShunLi

    2014-01-01

    Thermal expansion, defined as the temperature dependence of volume under constant pressure, is a common phenomenon in nature and originates from anharmonic lattice dynamics. However, it has been poorly understood how thermal expansion can show anomalies such as colossal positive, zero, or negative thermal expansion (CPTE, ZTE, or NTE), especially in quantitative terms. Here we show that changes in configurational entropy due to metastable micro(scopic)states can lead to quantitative prediction of these anomalies. We integrate the Maxwell relation, statistic mechanics, and first-principles calculations to demonstrate that when the entropy is increased by pressure, NTE occurs such as in Invar alloy (Fe3Pt, for example), silicon, ice, and water, and when the entropy is decreased dramatically by pressure, CPTE is expected such as in anti-Invar cerium, ice and water. Our findings provide a theoretic framework to understand and predict a broad range of anomalies in nature in addition to thermal expansion, which may include gigantic electrocaloric and electromechanical responses, anomalously reduced thermal conductivity, and spin distributions. PMID:25391631

  4. No evidence for directional evolution of body mass in herbivorous theropod dinosaurs

    PubMed Central

    Zanno, Lindsay E.; Makovicky, Peter J.

    2013-01-01

    The correlation between large body size and digestive efficiency has been hypothesized to have driven trends of increasing mass in herbivorous clades by means of directional selection. Yet, to date, few studies have investigated this relationship from a phylogenetic perspective, and none, to our knowledge, with regard to trophic shifts. Here, we reconstruct body mass in the three major subclades of non-avian theropod dinosaurs whose ecomorphology is correlated with extrinsic evidence of at least facultative herbivory in the fossil recordall of which also achieve relative gigantism (more than 3000 kg). Ordinary least-squares regressions on natural log-transformed mean mass recover significant correlations between increasing mass and geological time. However, tests for directional evolution in body mass find no support for a phylogenetic trend, instead favouring passive models of trait evolution. Cross-correlation of sympatric taxa from five localities in Asia reveals that environmental influences such as differential habitat sampling and/or taphonomic filtering affect the preserved record of dinosaurian body mass in the Cretaceous. Our results are congruent with studies documenting that behavioural and/or ecological factors may mitigate the benefit of increasing mass in extant taxa, and suggest that the hypothesis can be extrapolated to herbivorous lineages across geological time scales. PMID:23193135

  5. Creating the brain and interacting with the brain: an integrated approach to understanding the brain

    PubMed Central

    Morimoto, Jun; Kawato, Mitsuo

    2015-01-01

    In the past two decades, brain science and robotics have made gigantic advances in their own fields, and their interactions have generated several interdisciplinary research fields. First, in the understanding the brain by creating the brain approach, computational neuroscience models have been applied to many robotics problems. Second, such brain-motivated fields as cognitive robotics and developmental robotics have emerged as interdisciplinary areas among robotics, neuroscience and cognitive science with special emphasis on humanoid robots. Third, in brainmachine interface research, a brain and a robot are mutually connected within a closed loop. In this paper, we review the theoretical backgrounds of these three interdisciplinary fields and their recent progress. Then, we introduce recent efforts to reintegrate these research fields into a coherent perspective and propose a new direction that integrates brain science and robotics where the decoding of information from the brain, robot control based on the decoded information and multimodal feedback to the brain from the robot are carried out in real time and in a closed loop. PMID:25589568

  6. New Indivisible Planetary Science Paradigm

    E-print Network

    Herndon, J Marvin

    2013-01-01

    I present here a new, indivisible planetary science paradigm, a wholly self-consistent vision of the nature of matter in the Solar System, and dynamics and energy sources of planets. Massive-core planets formed by condensing and raining-out from within giant gaseous protoplanets at high pressures and high temperatures. Earth's complete condensation included a 300 Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66% of Earth's present diameter. T-Tauri eruptions stripped the gases away from the inner planets and stripped a portion of Mercury's incompletely condensed protoplanet, and transported it to the region between Mars and Jupiter where it fused with in-falling oxidized condensate from the outer regions of the Solar System and formed the parent matter of ordinary chondrite meteorites, the main-Belt asteroids, and veneer for the inner planets, especially Mars. In response to decompression-driven planetary volume increases, cracks form to increase surface area and mountain ranges ...

  7. Tailoring the magnetoelectric coupling in the Co2Y type hexaferrite single crystals by systematic doping control

    NASA Astrophysics Data System (ADS)

    Shin, Kwangwoo; Park, Chang Bae; Chun, Sae Hwan; Kim, Kee Hoon

    2015-03-01

    Hexagonal ferrites have shown gigantic magnetoelectric (ME) coupling in a broad temperature range including room temperature, which draws great interests due to their rich physics and various application potential. Here, we report the variations of the ME coupling and electrical phase boundary in the Sr and Al doped Co2Y type single crystal. As the doping ratio of Sr and Al ions increased, not only the transition temperature of the heliconical spin ordering increased up to 430 K, but also the ferroelectric phase boundary became closer to the zero magnetic field. These two main effects lead us to observe the large direct and converse ME effects at room temperature and near zero magnetic field. In particular, in an optimally doped sample, the ME susceptibility reaches to 28,000 ps/m at 10 K and the magnetization direction could be reversed by an external electric field even at 250 K without any bias magnetic field. These results clearly show that the Co2Y type hexaferrite is a promising material system that might realize the magnetization reversal even at room temperature.

  8. Origin of marginal basins of the NW Pacific and their plate tectonic reconstructions

    NASA Astrophysics Data System (ADS)

    Xu, Junyuan; Ben-Avraham, Zvi; Kelty, Tom; Yu, Ho-Shing

    2014-03-01

    Geometry of basins can indicate their tectonic origin whether they are small or large. The basins of Bohai Gulf, South China Sea, East China Sea, Japan Sea, Andaman Sea, Okhotsk Sea and Bering Sea have typical geometry of dextral pull-apart. The Java, Makassar, Celebes and Sulu Seas basins together with grabens in Borneo also comprise a local dextral, transform-margin type basin system similar to the central and southern parts of the Shanxi Basin in geometry. The overall configuration of the Philippine Sea resembles a typical sinistral transpressional "pop-up" structure. These marginal basins except the Philippine Sea basin generally have similar (or compatible) rift history in the Cenozoic, but there do be some differences in the rifting history between major basins or their sub-basins due to local differences in tectonic settings. Rifting kinematics of each of these marginal basins can be explained by dextral pull-apart or transtension. These marginal basins except the Philippine Sea basin constitute a gigantic linked, dextral pull-apart basin system.

  9. The formation of large galactic disks: revival or survival?

    NASA Astrophysics Data System (ADS)

    Hammer, F.; Puech, M.; Flores, H.; Athanassoula, E.; Yang, Y. B.; Wang, J. L.; Rodrigues, M.; Fouquet, S.

    2011-12-01

    Using the deepest and the most complete set of observations of distant galaxies, we investigate how extended disks could have formed. Observations include spatially-resolved kinematics, detailed morphologies and photometry from UV to mid-IR. Six billion years ago, half of the present-day spiral progenitors had anomalous kinematics and morphologies, as well as relatively high gas fractions. We argue that gas-rich major mergers, i.e., fusions between gas-rich disk galaxies of similar mass, can be the likeliest driver for such strong peculiarities. This suggests a new channel of disk formation, e.g. many disks could be reformed after gas-rich mergers. This is found to be in perfect agreement with predictions from the state-of-the-art ?CDM semi-empirical models: due to our sensitivity in detecting mergers at all phases, from pairs to relaxed post-mergers, we find a more accurate merger rate. The scenario can be finally confronted to properties of nearby galaxies, including M31 and galaxies showing ultra-faint, gigantic structures in their haloes.

  10. Haploinsufficiency of Anx7 tumor suppressor gene and consequent genomic instability promotes tumorigenesis in the Anx7(+/-) mouse

    PubMed Central

    Srivastava, Meera; Montagna, Cristina; Leighton, Ximena; Glasman, Mirta; Naga, Shanmugam; Eidelman, Ofer; Ried, Thomas; Pollard, Harvey B.

    2003-01-01

    Annexin 7 (ANX7) acts as a tumor suppressor gene in prostate cancer, where loss of heterozygosity and reduction of ANX7 protein expression is associated with aggressive metastatic tumors. To investigate the mechanism by which this gene controls tumor development, we have developed an Anx7(+/-) knockout mouse. As hypothesized, the Anx7(+/-) mouse has a cancer-prone phenotype. The emerging tumors express low levels of Anx7 protein. Nonetheless, the wild-type Anx7 allele is detectable in laser-capture microdissection-derived tumor tissue cells. Genome array analysis of hepatocellular carcinoma tissue indicates that the Anx7(+/-) genotype is accompanied by profound reductions of expression of several other tumor suppressor genes, DNA repair genes, and apoptosis-related genes. In situ analysis by tissue imprinting from chromosomes in the primary tumor and spectral karyotyping analysis of derived cell lines identify chromosomal instability and clonal chromosomal aberrations. Furthermore, whereas 23% of the mutant mice develop spontaneous neoplasms, all mice exhibit growth anomalies, including gender-specific gigantism and organomegaly. We conclude that haploinsufficiency of Anx7 expression appears to drive disease progression to cancer because of genomic instability through a discrete signaling pathway involving other tumor suppressor genes, DNA-repair genes, and apoptosis-related genes. PMID:14608035

  11. [Developments of the bone and joint decade in the area of emergency medicine activity].

    PubMed

    H?adki, Waldemar; Trybus, Marek; Lorkowski, Jacek; Brongel, Leszek

    2006-01-01

    Emergency medicine in our country is still a new medical discipline, which is develope in spite of objective connected difficulties with generally well-known problems of medical service in Poland. Essential part of patients treated on the field of activity of rescue--medicine are victims with injuries of osteoarticular system. According to many authors determine they to 40% patients provided in pre-hospital care time. Development of Polish emergency medicine happens on period of Decade of the Bone and Joint, declared by the World Health Organization on years 2000-2010. Consequences of bones and joints injuries are the reason protracted pain complaints and physical disability of gigantic number of patients. The goal of the Decade are among other things, activities aiming to improvement of efficiency of osteoarticular system injuries on place of event and in emergency medicine departments, in accordance to accepted procedures. It is an extremely essential meaning for patient's future and of final results of treatment, and a quality of life of these people. In Clinic of Emergency Medicine and Multiple Injuries in relationship to Decade of the Bone and Joint we investigate problems concerning diagnostics procedures and initial medical management of isolated osteoarticular injuries, and coexisted with injuries of other body regions. In this study we present management strategy of osteoarticular injuries in emergency medicine in aspect of goals realization of the Decade of the Bone and Joint. PMID:17469517

  12. DNA Viruses: The Really Big Ones (Giruses)

    PubMed Central

    Van Etten, James L.; Lane, Leslie C.; Dunigan, David D.

    2010-01-01

    Viruses with genomes greater than 300 kb and up to 1200 kb are being discovered with increasing frequency. These large viruses (often called giruses) can encode up to 900 proteins and also many tRNAs. Consequently, these viruses have more protein-encoding genes than many bacteria, and the concept of small particle/small genome that once defined viruses is no longer valid. Giruses infect bacteria and animals although most of the recently discovered ones infect protists. Thus, genome gigantism is not restricted to a specific host or phylogenetic clade. To date, most of the giruses are associated with aqueous environments. Many of these large viruses (phycodnaviruses and Mimiviruses) probably have a common evolutionary ancestor with the poxviruses, iridoviruses, asfarviruses, ascoviruses, and a recently discovered Marseillevirus. One issue that is perhaps not appreciated by the microbiology community is that large viruses, even ones classified in the same family, can differ significantly in morphology, lifestyle, and genome structure. This review focuses on some of these differences rather than provides extensive details about individual viruses. PMID:20690825

  13. Parasitism and phenotypic change in colonial hosts.

    PubMed

    Hartikainen, Hanna; Fontes, Ins; Okamura, Beth

    2013-09-01

    Changes in host phenotype are often attributed to manipulation that enables parasites to complete trophic transmission cycles. We characterized changes in host phenotype in a colonial hostendoparasite system that lacks trophic transmission (the freshwater bryozoan Fredericella sultana and myxozoan parasite Tetracapsuloides bryosalmonae). We show that parasitism exerts opposing phenotypic effects at the colony and module levels. Thus, overt infection (the development of infectious spores in the host body cavity) was linked to a reduction in colony size and growth rate, while colony modules exhibited a form of gigantism. Larger modules may support larger parasite sacs and increase metabolite availability to the parasite. Host metabolic rates were lower in overtly infected relative to uninfected hosts that were not investing in propagule production. This suggests a role for direct resource competition and active parasite manipulation (castration) in driving the expression of the infected phenotype. The malformed offspring (statoblasts) of infected colonies had greatly reduced hatching success. Coupled with the severe reduction in statoblast production this suggests that vertical transmission is rare in overtly infected modules. We show that although the parasite can occasionally infect statoblasts during overt infections, no infections were detected in the surviving mature offspring, suggesting that during overt infections, horizontal transmission incurs a trade-off with vertical transmission. PMID:23965820

  14. The effects of density on the topological structure of the mitochondrial DNA from trypanosomes.

    PubMed

    Diao, Y; Hinson, K; Kaplan, R; Vazquez, M; Arsuaga, J

    2012-05-01

    Trypanosomatida parasites, such as trypanosoma and lishmania, are the cause of deadly diseases in many third world countries. A distinctive feature of these organisms is the three dimensional organization of their mitochondrial DNA into maxi and minicircles. In some of these organisms minicircles are confined into a small disk volume and are topologically linked, forming a gigantic linked network. The origins of such a network as well as of its topological properties are mostly unknown. In this paper we quantify the effects of the confinement on the topology of such a minicircle network. We introduce a simple mathematical model in which a collection of randomly oriented minicircles are spread over a rectangular grid. We present analytical and computational results showing that a finite positive critical percolation density exists, that the probability of formation of a highly linked network increases exponentially fast when minicircles are confined, and that the mean minicircle valence (the number of minicircles that a particular minicircle is linked to) increases linearly with density. When these results are interpreted in the context of the mitochondrial DNA of the trypanosome they suggest that confinement plays a key role on the formation of the linked network. This hypothesis is supported by the agreement of our simulations with experimental results that show that the valence grows linearly with density. Our model predicts the existence of a percolation density and that the distribution of minicircle valences is more heterogeneous than initially thought. PMID:21671031

  15. Chemical control of downy mildew on lettuce and basil under greenhouse.

    PubMed

    Gullino, M L; Gilardi, G; Garibaldi, A

    2009-01-01

    Eight experimental trials were carried out during 2007 and 2008 to evaluate the efficacy of different fungicides against downy mildew of lettuce (Bremia lactucae) and basil (Peronospora belbahrii) under greenhouse conditions, at temperatures ranging from 19 to 24 degrees C. The mixture fluopicolide (fungicide belonging to the + propamocarb hydrochloride (fungicide belonging to the new chemical class of acyl-picolides) was compared with metalaxyl m + copper, zoxamide + mancozeb, iprovalicarb + Cu, fenamidone + fosetyl-Al and azoxystrobin. Two treatments were carried out at 8-12 day interval on lettuce and basil. The artificial inoculation of B. lactucae on lettuce (cv Cobham Green) and P. belbahrii. on basil (cv Genovese gigante) was carried out by using 1 x 10(5) CFU/ml 24 h after the first treatment. In the presence of a medium-high disease severity, all fungicides tested in these trials were effective against downy mildew on lettuce and basil as the other fungicides already available. The importance of the availability of a number of different chemicals to control downy mildews is discussed. PMID:20222581

  16. Simulations of high-Tc superconductors using the DCA+ algorithm

    NASA Astrophysics Data System (ADS)

    Staar, Peter

    2015-03-01

    For over three decades, the high Tc-cuprates have been a gigantic challenge for condensed matter theory. Even the simplest representation of these materials, i.e. the single band Hubbard model, is hard to solve quantitatively and its phase-diagram is therefore elusive. In this talk, we present the recent algorithmic and implementation advances to the Dynamical Cluster Approximation (DCA). The algorithmic advances allow us to determine self-consistently a continuous self-energy in momentum space, which in turn reduces the cluster-shape dependency of the superconducting transition temperature and thus accelerates the convergence of the latter versus cluster-size. Furthermore, the introduction of the smooth self-energy suppresses artificial correlations and thus reduces the fermionic sign-problem, allowing us to simulate larger clusters at much lower temperatures. By combining these algorithmic improvements with a very efficient GPU accelerated QMC-solver, we are now able to determine the superconducting transition temperature accurately and show that the Cooper-pairs have indeed a d-wave structure, as was predicted by Zhang and Rice.

  17. Crustal structure of Shatsky Rise from joint refraction and reflection seismic tomography

    NASA Astrophysics Data System (ADS)

    Korenaga, J.; Sager, W. W.

    2011-12-01

    Shatsky Rise in the western Pacific is one of a few gigantic oceanic plateaus in the world, with a surface area of 4.8 105~km2 (about the same size as California). In contrast to other large oceanic plateaus formed during the Cretaceous Quite Period, Shatsky Rise formed during the frequent reversals of magnetic polarity, allowing its tectonic environment to be resolved in detail. It was formed at a rapidly spreading ridge-ridge-ridge triple junction, so the effect of lithospheric lid on magma migration is expected to be minimal, thereby facilitating the petrological interpretation of its seismic structure in terms of parental mantle processes. In the summer of 2010, a seismic refraction survey combined with multichannel seismic profiling was conducted across Shatsky Rise. Twenty eight ocean-bottom seismometers were deployed along two crossing perpendicular lines, and all of the instruments were recovered successfully, yielding a large volume of high-quality wide-angle refraction and reflection data, with the source-receiver distance often exceeding 200~km. In this contribution, we present the P-wave velocity structure of the Shatsky Rise crust, which is constructed by joint refraction and reflection travel time tomography, and also discuss its implications for the origin of Shatsky Rise.

  18. Radiation of a uniformly moving line charge in a zero-index metamaterial and other periodic media.

    PubMed

    Yanai, Avner; Levy, Uriel

    2012-07-30

    Radiation of electromagnetic waves by a uniformly moving charge is the subject of extensive research over the last several decades. Fascinating effects such as Vavilov-Cherenkov radiation, transition radiation and the Smith-Purcell effect were discovered and studied in depth. In this letter we study the radiation of a line charge moving with relativistic constant velocity within an average zero index metamaterial consisting of periodically alternating layers with negative and positive refractive index. We observe a strong radiation enhancement, ~3 orders of magnitude, for specific combinations of velocities and radiation frequencies. This surprising finding is attributed to a gigantic increase in the density of states at the positive/negative index boundary. Furthermore, we shed light on radiation effects of such a line charge propagating within the more "traditional" structure of periodically alternating layers consisting of positive and different refractive index with focus on frequencies satisfying the quarter wave stack and the half wave stack conditions. We show that the quarter-wave-stack case results in emission propagating vertically to the line charge trajectory, while the half-wave-stack results in negligible radiation. All these findings were obtained using a computationally efficient and conceptually intuitive computation method, based on eigenmode expansion of specific frequency components. For validation purposes this method was compared with the finite-difference-time-domain method. PMID:23038401

  19. What big eyes you have: the ecological role of giant pterygotid eurypterids.

    PubMed

    Anderson, Ross P; McCoy, Victoria E; McNamara, Maria E; Briggs, Derek E G

    2014-07-01

    Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi, there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night. PMID:25009243

  20. The Kunlun Fault

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Kunlun fault is one of the gigantic strike-slip faults that bound the north side of Tibet. Left-lateral motion along the 1,500-kilometer (932-mile) length of the Kunlun has occurred uniformly for the last 40,000 years at a rate of 1.1 centimeter per year, creating a cumulative offset of more than 400 meters. In this image, two splays of the fault are clearly seen crossing from east to west. The northern fault juxtaposes sedimentary rocks of the mountains against alluvial fans. Its trace is also marked by lines of vegetation, which appear red in the image. The southern, younger fault cuts through the alluvium. A dark linear area in the center of the image is wet ground where groundwater has ponded against the fault. Measurements from the image of displacements of young streams that cross the fault show 15 to 75 meters (16 to 82 yards) of left-lateral offset. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) acquired the visible light and near infrared scene on July 20, 2000. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team

  1. Atmospheric oxygen level and the evolution of insect body size

    PubMed Central

    Harrison, Jon F.; Kaiser, Alexander; VandenBrooks, John M.

    2010-01-01

    Insects are small relative to vertebrates, possibly owing to limitations or costs associated with their blind-ended tracheal respiratory system. The giant insects of the late Palaeozoic occurred when atmospheric PO2 (aPO2) was hyperoxic, supporting a role for oxygen in the evolution of insect body size. The paucity of the insect fossil record and the complex interactions between atmospheric oxygen level, organisms and their communities makes it impossible to definitively accept or reject the historical oxygen-size link, and multiple alternative hypotheses exist. However, a variety of recent empirical findings support a link between oxygen and insect size, including: (i) most insects develop smaller body sizes in hypoxia, and some develop and evolve larger sizes in hyperoxia; (ii) insects developmentally and evolutionarily reduce their proportional investment in the tracheal system when living in higher aPO2, suggesting that there are significant costs associated with tracheal system structure and function; and (iii) larger insects invest more of their body in the tracheal system, potentially leading to greater effects of aPO2 on larger insects. Together, these provide a wealth of plausible mechanisms by which tracheal oxygen delivery may be centrally involved in setting the relatively small size of insects and for hyperoxia-enabled Palaeozoic gigantism. PMID:20219733

  2. Using a smart phone application to measure high-energy radiation from thunderstorms

    NASA Astrophysics Data System (ADS)

    Bowers, G. S.; Smith, D. M.; Rexroad, W. Z.; Kelley, N. A.; Martinez-Mckinney, F.; Rubenstein, E. P.; Drukier, G.; Benes, G. N.

    2013-12-01

    Commercial airline flights and developing cell phone technologies present a burgeoning opportunity for the public to help investigate radiation from thunderstorms, including terrestrial gamma-ray flashes (TGFs), longer-lived gamma-ray glows, x-rays from lightning stepped leaders, and possible high-energy radiation, never yet observed, from blue jets, gigantic jets, and blue starters. GammaPix is a smartphone application from Image Insight, Inc. that uses the camera's CCD or CMOS sensor to identify and qualitatively assess threats related to gamma radioactivity, e.g., those caused by accidental exposure to radioactive material, high-altitude air travel, or acts of terrorism. A science-oriented version of the app is under development that will be publicized for use aboard commercial airline flights and on the ground in regions (like Japan in the wintertime) where thunderstorm charge centers come close to the ground. The primary goal of the project is to learn whether TGFs close to passenger aircraft and population centers on the ground occur often enough to create concern about radiation risk.

  3. Sobre el estado evolutivo de ? Pictoris

    NASA Astrophysics Data System (ADS)

    Brunini, A.; Benvenuto, O. G.

    Desde el descubrimiento de fuertes excesos infrarrojos en ? Pictoris, esta estrella ha sido muy estudiada y es considerada candidata a poseer un sistema planetario propio. ? Pic est rodeada de un disco asimtrico de polvo que se observa de canto y que esta vaco a distancias <= 40 AU. Esto se considera una fuerte evidencia en favor de la presencia de (al menos) un planeta gigante. Recientemente se han observado lneas de material circunestelar que se han interpretado como consecuencia de la cada de objetos cometarios sobre esta estrella. Recientemente se ha utilizado la existencia del disco de polvo para atribuir una edad corta (pre - secuencia principal) a ?Pic. Sin embargo, la evaporacin de estos cometas provee suficiente polvo como para explicar la presencia del disco observado sin necesidad de edades cortas. En este trabajo mostramos que la comparacin entre la tasa de impactos cometarios estimada en el Sistema Solar para diferentes etapas de su evolucin y los datos observados en ? Pic indica edades avanzadas para ? Pic. Esta estimacin debe tomarse con cautela ya que depende de la estructura de los sistemas planetarios. Adems mostramos que, desde el punto de vista de la evolucin estelar y con las incertezas presentes en la luminosidad y la temperatura efectiva, existe un continuo de edades posible para ? Pic. Sin embargo, empleando los datos provenientes de los flujos cometarios encontramos que una edad prolongada es consistente con ambos tratamientos.

  4. The Influence of Extremely Large Solar Proton Events in a Changing Stratosphere. Stratospheric Influence of Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Fleming, Eric L.; Vitt, Francis M.

    1999-01-01

    Two periods of extremely large solar proton events (SPEs) occurred in the past thirty years, which forced significant long-term polar stratospheric changes. The August 2-10, 1972 and October 19-27, 1989 SPEs happened in stratospheres that were quite different chemically. The stratospheric chlorine levels were relatively small in 1972 (approximately 1.2 ppbv) and were fairly substantial in 1989 at about (approximately 3 ppbv). Although these SPEs produced both HO(x) and NO(y) constituents in the mesosphere and stratosphere, only the NO(y) constituents had lifetimes long enough to affect ozone for several months to years past the events. Our recently improved two-dimensional chemistry and transport atmospheric model was used to compute the effects of these gigantic SPEs in a changing stratosphere. Significant upper stratospheric ozone depletions > 10% are computed to last for a few months past these SPEs. The long-lived SPE-produced NO(y) constituents were transported to lower levels during winter after these huge SPEs and caused impacts in the middle and lower stratosphere. During periods of high halogen loading these impacts resulted in interference with the chlorine and bromine loss cycles for ozone destruction. The chemical state of the atmosphere, including the stratospheric sulfate aerosol density, substantially affected the predicted stratospheric influence of these extremely large SPEs.

  5. Embryonic and paralarval development of the central nervous system of the loliginid squid Sepioteuthis lessoniana.

    PubMed

    Shigeno, S; Tsuchiya, K; Segawa, S

    2001-09-01

    The embryonic development of the central nervous system (CNS) in the oval squid Sepioteuthis lessoniana is described. It has three distinct phases: (1) The ganglionic accumulation phase: Ganglionic cell clusters develop by ingression, migration, and accumulation of neuroblasts. (2) The lobe differentiation phase: Ganglia differentiate into lobes. The phase is identified by the beginning of an axogenesis. During this phase, neuropils are first formed in the suboesophageal mass, then in the basal lobe system, and finally in the inferior frontal lobes and the superior frontal-vertical lobe systems. (3) The neuropil increment phase: After the shape of the lobes reached its typical form, neuropil growth occurs, specifically in the vertical lobe. The paralarval central nervous system (CNS) is characterized by neuronal gigantism of the giant fibers and some suboesophageal commissures and connectives. The neuropil formation in the CNS of S. lessoniana occurs somewhat earlier than in Octopus vulgaris, although the principal developmental plan is quite conservative among the other coleoids investigated. Some phylogenetic aspects are discussed based on the similarities in the morphologic organization of their brains. PMID:11503146

  6. Low-field magnetoelectric effect at room temperature.

    PubMed

    Kitagawa, Yutaro; Hiraoka, Yuji; Honda, Takashi; Ishikura, Taishi; Nakamura, Hiroyuki; Kimura, Tsuyoshi

    2010-10-01

    The discoveries of gigantic ferroelectric polarization in BiFeO(3) (ref. 1) and ferroelectricity accompanied by a magnetic order in TbMnO(3) (ref. 2) have renewed interest in research on magnetoelectric multiferroics, materials in which magnetic and ferroelectric orders coexist, from both fundamental and technological points of view. Among several different types of magnetoelectric multiferroic, magnetically induced ferroelectrics in which ferroelectricity is induced by complex magnetic orders, such as spiral orders, exhibit giant magnetoelectric effects, remarkable changes in electric polarization in response to a magnetic field. Many magnetically induced ferroelectrics showing the magnetoelectric effects have been found in the past several years. From a practical point of view, however, their magnetoelectric effects are useless because they operate only far below room temperature (for example, 28 K in TbMnO(3) (ref. 2) and 230 K in CuO (ref. 11)). Furthermore, in most of them, the operating magnetic field is an order of tesla that is too high for practical applications. Here we report materials, Z-type hexaferrites, overcoming these problems on magnetically induced ferroelectrics. The best magnetoelectric properties were obtained for Sr(3)Co(2)Fe(24)O(41) ceramics sintered in oxygen, which exhibit a low-field magnetoelectric effect at room temperature. Our result represents an important step towards practical device applications using the magnetoelectric effects. PMID:20693994

  7. Giant spin-driven ferroelectric polarization in TbMnO3 under high pressure

    NASA Astrophysics Data System (ADS)

    Aoyama, T.; Yamauchi, K.; Iyama, A.; Picozzi, S.; Shimizu, K.; Kimura, T.

    2014-09-01

    The recent research on multiferroics has provided solid evidence that the breaking of inversion symmetry by spin order can induce ferroelectric polarization P. This type of multiferroics, called spin-driven ferroelectrics, often show a gigantic change in P on application of a magnetic field B. However, their polarization (<~0.1??C?cm?2) is much smaller than that in conventional ferroelectrics (typically several to several tens of ?C?cm?2). Here we show that the application of external pressure to a representative spin-driven ferroelectric, TbMnO3, causes a flop of P and leads to the highest P (?1.0??C?cm?2) among spin-driven ferroelectrics ever reported. We explain this behaviour in terms of a pressure-induced magnetoelectric phase transition, based on the results of density functional simulations. In the high-pressure phase, the application of B further enhances P over 1.8??C?cm?2. This value is nearly an order of magnitude larger than those ever reported in spin-driven ferroelectrics.

  8. Low-field magnetoelectric effect at room temperature

    NASA Astrophysics Data System (ADS)

    Kitagawa, Yutaro; Hiraoka, Yuji; Honda, Takashi; Ishikura, Taishi; Nakamura, Hiroyuki; Kimura, Tsuyoshi

    2010-10-01

    The discoveries of gigantic ferroelectric polarization in BiFeO3 (ref. 1) and ferroelectricity accompanied by a magnetic order in TbMnO3 (ref. 2) have renewed interest in research on magnetoelectric multiferroics, materials in which magnetic and ferroelectric orders coexist, from both fundamental and technological points of view. Among several different types of magnetoelectric multiferroic, magnetically induced ferroelectrics in which ferroelectricity is induced by complex magnetic orders, such as spiral orders, exhibit giant magnetoelectric effects, remarkable changes in electric polarization in response to a magnetic field. Many magnetically induced ferroelectrics showing the magnetoelectric effects have been found in the past several years. From a practical point of view, however, their magnetoelectric effects are useless because they operate only far below room temperature (for example, 28K in TbMnO3 (ref. 2) and 230K in CuO (ref. 11)). Furthermore, in most of them, the operating magnetic field is an order of tesla that is too high for practical applications. Here we report materials, Z-type hexaferrites, overcoming these problems on magnetically induced ferroelectrics. The best magnetoelectric properties were obtained for Sr3Co2Fe24O41 ceramics sintered in oxygen, which exhibit a low-field magnetoelectric effect at room temperature. Our result represents an important step towards practical device applications using the magnetoelectric effects.

  9. Wireless Transfer of Electricity in Outer Space

    E-print Network

    Alexander Bolonkin

    2008-05-07

    Author offers conclusions from his research of a revolutionary new idea - transferring electric energy in the hard vacuum of outer space wirelessly, using a plasma power cord as an electric cable (wire). He shows that a certain minimal electric currency creates a compressed force that supports the plasma cable in the compacted form. A large energy can be transferred hundreds of millions of kilometers by this method. The required mass of the plasma cable is only hundreds of grams. He computed the macroprojects: transference of hundreds kilowatts of energy to Earth Space Station, transferring energy to the Moon or back, transferring energy to a spaceship at distance 100 million of kilometers, the transfer energy to Mars when one is located at opposed side of the distant Sun, transfer colossal energy from one of Earth's continents to another continent (for example, between Europe-USA) wirelessly-using Earth ionosphere as cable, using Earth as gigantic storage of electric energy, using the plasma ring as huge MagSail for moving of spaceships. He also demonstrates that electric currency in a plasma cord can accelerate or brake spacecraft and space apparatus.

  10. The Internal Subbetic of the Velez Rubio area (SE Spain): Is it tectonically detached or not?

    NASA Astrophysics Data System (ADS)

    Sanz de Galdeano, Carlos; Lpez Garrido, Angel Carlos; Andreo, Bartolom

    2015-01-01

    The sierras of Maria and Maimon form part of the Internal Subbetic in the eastern part of the Betic Cordillera, in contact with the Internal Zone. Previous papers have interpreted the Internal Subbetic as being tectonically detached at its bottom, thrusting the Solana Fm., and moreover thrusting the Internal Zone. Nevertheless, the analysis of the structure of these sierras (with great development of folds), and that of the Sierra del Gigante, indicates that this detachment does not exist and, on the contrary, the structure is clearly rooted. Moreover, the general rectilinear trend of the contact between the Internal and External Zones leads to the interpretation that it in fact corresponds to a dextral transcurrent contact, this contention being supported by the analysis of minor faults. According to the age of the younger sediments involved (the Espejos and Solana Fms.), the main deformation processes occurred from the early Miocene and continued during the middle Miocene, at least in part. The structure and characteristics of the geologic evolution of this area are comparable to that of the Internal Subbetic (Penibetic) in the western part of the cordillera.

  11. Comportamiento dinmico de asteroides en la regin 23 < a < 26 UA

    NASA Astrophysics Data System (ADS)

    Lpez Garca, F.

    Los Kuiper Belt Objects (KBOs) pueden ser una fuente de origen de los cometas de corto perodo. Muchos de los KBOs observados parecen provenir, al igual que el sistema Pluton-Charonte, de rbitas resonantes con Neptuno. Los Centauros son objetos que dinmicamente provienen de rbitas inestables cuyo semieje mayor se encuentra entre las rbitas de Jpiter y Neptuno. Pudiera ser que estos cuerpos fueron expulsados desde la regin del cinturn de Kuiper y se encuentran en un proceso de ``scattering" debido a los efectos gravitacionales de los planetas gigantes. Su tiempo de vida dinmico es de algunos millones de aos. La evolucin orbital de los objetos trans-Neptunianos nos permite conocer su comportamiento anterior, por eso, es importante su relacin dinmica con la evolucin orbital de Neptuno. El objeto de este trabajo es estudiar el comportamiento dinmico de partculas test que se encuentran entre las resonancias 3:2 con Neptuno y 2:3 con Urano, las cuales comprenden una regin de 2 UA aproximadamente. Los primeros resultados indican que la mayora de los objetos ficticios son eyectados hacia la parte externa del Sistema Solar, mientras que slo una parte pequea del total de objetos estudiados, aproximadamente un 7%, son eyectados hacia la parte interna del Sistema Solar, y en algunos casos sus rbitas pueden cruzar la rbita de los planetas terrestres.

  12. Structural Control of Giant Rock Avalanches in Argentina

    NSDL National Science Digital Library

    Barb Tewksbury

    Jigsaw version: To prepare, students do background reading on landslides and rock avalanches and read the introductory portion of Hermanns and Strecker's 1999 article on rock avalanches in Argentina. In class, students receive data (assembled from figures in the article) on bedrock geology and physiography, as well as stereonets showing orientations of prominent joint sets, bedding, and foliations in the bedrock. Their task is to answer the question of why gigantic rock avalanches occur is some places but not others in this part of Argentina. Each student receives one of four possible data sets and works with a team to analyze the data and solve the problem for the team's area. Each team member must then individually explain his/her analysis to a group of three other students, one from each of the other teams, and the group then compares the four locations for similarities and differences. The activity gives students practice in interpreting geologic maps, using stereonets, and peer teaching. The activity also connects structural geology to another geoscience discipline.Short case example version: This is an abbreviated version of the jigsaw activity described above and focuses on only one of the rock avalanche areas.

  13. Wafer-scale metasurface for total power absorption, local field enhancement and single molecule Raman spectroscopy.

    PubMed

    Wang, Dongxing; Zhu, Wenqi; Best, Michael D; Camden, Jon P; Crozier, Kenneth B

    2013-01-01

    The ability to detect molecules at low concentrations is highly desired for applications that range from basic science to healthcare. Considerable interest also exists for ultrathin materials with high optical absorption, e.g. for microbolometers and thermal emitters. Metal nanostructures present opportunities to achieve both purposes. Metal nanoparticles can generate gigantic field enhancements, sufficient for the Raman spectroscopy of single molecules. Thin layers containing metal nanostructures ("metasurfaces") can achieve near-total power absorption at visible and near-infrared wavelengths. Thus far, however, both aims (i.e. single molecule Raman and total power absorption) have only been achieved using metal nanostructures produced by techniques (high resolution lithography or colloidal synthesis) that are complex and/or difficult to implement over large areas. Here, we demonstrate a metasurface that achieves the near-perfect absorption of visible-wavelength light and enables the Raman spectroscopy of single molecules. Our metasurface is fabricated using thin film depositions, and is of unprecedented (wafer-scale) extent. PMID:24091825

  14. Energy and globalization

    NASA Astrophysics Data System (ADS)

    Birjandi, Hossein Saremi

    Before the Industrial Revolution, nations required no energy fuel. People relied on human, animal, and wind and waterpower for energy need. Energy (oil) has resettled populations, elected officials in the free world, or changed the governments of the energy rich countries by force. Energy fueled wars, played the major factor in the might of those who have it or more importantly the abilities to acquire it by force. This dissertation researches the primacy of oil as an energy source from the time of oil's discovery to the present times. Between 1945 and 1960, the use of oil and gas doubled as power was generated for industries as steel, cement, metalworking and more important of all filling station hoses into automobiles gas tanks, thus energy swept people and societies quite literally off their feet. One in every six jobs in the industrial world hired by the giant automotive industries. The big five American oil companies spurred on by special tax benefit, these companies grew to gigantic sizes by taking out the best part of the nation's oil. Then, for greater growth, they leaped overseas and built up an immensely profitable system, in alliance with Anglo-Dutch Shell and British Petroleum, known as seven sisters. On the other side of the world, the energy producing nations form an alliance mainly to protect themselves from downward price fluctuations of oil. The struggle for survival in the global energy market forced those countries to get together and form OPEC, which is referred as an "oil cartel".

  15. Structure and expression pattern of human ALR, a novel gene with strong homology to ALL-1 involved in acute leukemia and to Drosophila trithorax.

    PubMed

    Prasad, R; Zhadanov, A B; Sedkov, Y; Bullrich, F; Druck, T; Rallapalli, R; Yano, T; Alder, H; Croce, C M; Huebner, K; Mazo, A; Canaani, E

    1997-07-31

    The ALL-1 gene is involved in human acute leukemia through chromosome translocations or internal rearrangements. ALL-1 is the human homologue of Drosophila trithorax. The latter is a member of the trithorax group (trx-G) genes which together with the Polycomb group (Pc-G) genes act as positive and negative regulators, respectively, to determine the body structure of Drosophila. We have cloned a novel human gene, ALR, which encodes a gigantic 5262 amino acid long protein containing a SET domain, five PHD fingers, potential zinc fingers, and a very long run of glutamines interrupted by hydrophobic residues, mostly leucine. The SET motif, PDH fingers, zinc fingers and two other regions are most similar to domains of ALL-1 and TRX. The first two motifs are also found in other trx-G and Pc-G proteins. The ALR gene was mapped to chromosome band 12q12-13, adjacent to the VDR gene. This region is involved in duplications and translocations associated with cancer. The analysis of ALR expression showed that its approximately 18 kb long mRNA is expressed, like ALL-1, in most adult tissues, including a variety of hematopoietic cells, with the exception of the liver. Whole mount in situ hybridization to early mouse embryos indicates expression in multiple tissues. Based on similarities in structure and expression pattern, ALR is likely to play a similar role to ALL-1 and trx, although its target genes have yet to be identified. PMID:9247308

  16. The change of amyloplasts structure and composition of storage starch in potato minitubers during imitated microgravity

    NASA Astrophysics Data System (ADS)

    Nedukha, O. M.; Kordyum, E. L.; Martyn, G. M.; Schnyukova, E. I.

    Potato was designated for food production in the controlled ecological life-support system CELSS because its tubers as it is known contain starch and significant protein content and are edible food after the long-term storage We used the cultivation of potato miniplants under influence of long-term horizontal clinorotation 2 rev min which imitated microgravity as a model for the technology of potato food production in the CELSS The aim of our work was to determine content and composition storage starch as well as amyloplast ultrastructure of storage parenchyma cells in potato minitubers formed under long-term to 6 weeks slow horizontal clinorotation 2 rpm Minitubers developed from axillary buds of potato miniplants growing in the aseptic stationary conditions and under clinorotation Methods of scanning and transmission electron microscopy were used for the study of surface and ultrastructure of amyloplasts the biochemical method by Hovenkamp-Hermelink et al 1988 - for study of starch composition Some differences were observed in amyloplast structure under clinorotation namely increased volume of starch grains in plastid decreased stroma volume changed structure of envelope membranes in comparison with the stationary control Besides an appearance of fraction of gigantic amyloplasts in central layers of parenchyma was observed under clinorotation after 4 weeks of growth The total starch content increased and reached to 219 5 - 4 1 mg g FW at 6 weeks of clinorotation it was 167 5 - 5 6 mg g FW in the control minitubers A ratio of

  17. When did Carcharocles megalodon become extinct? A new analysis of the fossil record.

    PubMed

    Pimiento, Catalina; Clements, Christopher F

    2014-01-01

    Carcharocles megalodon ("Megalodon") is the largest shark that ever lived. Based on its distribution, dental morphology, and associated fauna, it has been suggested that this species was a cosmopolitan apex predator that fed on marine mammals from the middle Miocene to the Pliocene (15.9-2.6 Ma). Prevailing theory suggests that the extinction of apex predators affects ecosystem dynamics. Accordingly, knowing the time of extinction of C. megalodon is a fundamental step towards understanding the effects of such an event in ancient communities. However, the time of extinction of this important species has never been quantitatively assessed. Here, we synthesize the most recent records of C. megalodon from the literature and scientific collections and infer the date of its extinction by making a novel use of the Optimal Linear Estimation (OLE) model. Our results suggest that C. megalodon went extinct around 2.6 Ma. Furthermore, when contrasting our results with known ecological and macroevolutionary trends in marine mammals, it became evident that the modern composition and function of modern gigantic filter-feeding whales was established after the extinction of C. megalodon. Consequently, the study of the time of extinction of C. megalodon provides the basis to improve our understanding of the responses of marine species to the removal of apex predators, presenting a deep-time perspective for the conservation of modern ecosystems. PMID:25338197

  18. Ultrafast observation of critical nematic fluctuations and giant magnetoelastic coupling in iron pnictides

    SciTech Connect

    Patz, Aaron [Ames Laboratory; Li, Tianqi [Ames Laboratory; ran, Sheng [Ames Laboratory; Fernandes, Rafael M. [University of Minnesota; Schmalian, Joerg [Karlsruhe Institute of Technology; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory; Perakis, Ilias E. [University of Crete; Wang, Jigang [Ames Laboratory

    2014-02-06

    Many of the iron pnictides have strongly anisotropic normal-state characteristics, important for the exotic magnetic and superconducting behaviour these materials exhibit. Y et, the origin of the observed anisotropy is unclear. Electronically driven nematicity has been suggested, but distinguishing this as an independent degree of freedom from magnetic and structural orders is dif?cult, as these couple together to break the same tetragonal symmetry. Here we use time-resolved polarimetry to reveal critical nematic ?uctuations in unstrained Ba(Fe1 xCox)2As2. The femtosecond anisotropic response, which arises from the two-fold in-plane anisotropy of the complex refractive index, displays a characteristic two-step recovery absent in the isotropic response. The fast recovery appears only in the magnetically ordered state, whereas the slow one persists in the paramagnetic phase with a critical divergence approaching the structural transition temperature. The dynamics also reveal a gigantic magnetoelastic coupling that far exceeds electronspin and electronphonon couplings, opposite to conventional magnetic metals.

  19. Star Formation Histories in the Local Group

    E-print Network

    Thomas M. Brown

    2004-07-09

    Deep color magnitude diagrams extending to the main sequence provide the most direct measure of the detailed star formation history in a stellar population. With large investments of observing time, HST can obtain such data for populations out to 1 Mpc, but its field of view is extremely small in comparison to the size of Local Group galaxies. This limitation severely constrains our understanding of galaxy formation. For example, the largest galaxy in the Local Group, Andromeda, offers an ideal laboratory for studying the formation of large spiral galaxies, but the galaxy shows substructure on a variety of scales, presumably due to its violent merger history. Within its remaining lifetime, HST can only sample a few sight-lines through this complex galaxy. In contrast, a wide field imager could provide a map of Andromeda's halo, outer disk, and tidal streams, revealing the spatially-dependent star formation history in each structure. The same data would enable many secondary studies, such as the age variation in Andromeda's globular cluster system, gigantic samples of variable stars, and microlensing tracers of the galaxy's dark matter distribution.

  20. The evolutionary physiology of animal flight: paleobiological and present perspectives.

    PubMed

    Dudley, R

    2000-01-01

    Recent geophysical analyses suggest the presence of a late Paleozoic oxygen pulse beginning in the late Devonian and continuing through to the late Carboniferous. During this period, plant terrestrialization and global carbon deposition resulted in a dramatic increase in atmospheric oxygen levels, ultimately yielding concentrations potentially as high as 35% relative to the contemporary value of 21%. Such hyperoxia of the late Paleozoic atmosphere may have physiologically facilitated the initial evolution of insect flight metabolism. Widespread gigantism in late Paleozoic insects and other arthropods is also consistent with enhanced oxygen flux within diffusion-limited tracheal systems. Because total atmospheric pressure increases with increased oxygen partial pressure, concurrently hyperdense conditions would have augmented aerodynamic force production in early forms of flying insects. By the late Permian, evolution of decompositional microbial and fungal communities, together with disequilibrium in rates of carbon deposition, gradually reduced oxygen concentrations to values possibly as low as 15%. The disappearance of giant insects by the end of the Permian is consistent with extinction of these taxa for reasons of asphyxiation on a geological time scale. As with winged insects, the multiple historical origins of vertebrate flight in the late Jurassic and Cretaceous correlate temporally with periods of elevated atmospheric oxygen. Much discussion of flight performance in Archaeopteryx assumes a contemporary atmospheric composition. Elevated oxygen levels in the mid- to late Mesozoic would, however, have facilitated aerodynamic force production and enhanced muscle power output for ancestral birds, as well as for precursors to bats and pterosaurs. PMID:10845087

  1. New Indivisible Planetary Science Paradigm

    E-print Network

    J. Marvin Herndon

    2013-06-17

    I present here a new, indivisible planetary science paradigm, a wholly self-consistent vision of the nature of matter in the Solar System, and dynamics and energy sources of planets. Massive-core planets formed by condensing and raining-out from within giant gaseous protoplanets at high pressures and high temperatures. Earth's complete condensation included a 300 Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66% of Earth's present diameter. T-Tauri eruptions stripped the gases away from the inner planets and stripped a portion of Mercury's incompletely condensed protoplanet, and transported it to the region between Mars and Jupiter where it fused with in-falling oxidized condensate from the outer regions of the Solar System and formed the parent matter of ordinary chondrite meteorites, the main-Belt asteroids, and veneer for the inner planets, especially Mars. In response to decompression-driven planetary volume increases, cracks form to increase surface area and mountain ranges characterized by folding form to accommodate changes in curvature. The differences between the inner planets are primarily the consequence of different degrees of protoplanetary compression. The internal composition of Mercury is calculated by analogy with the Earth. The rationale is provided for Mars potentially having a greater subsurface water reservoir capacity than before realized.

  2. Electric field effects in transition metal oxides, their surfaces and heterostructures

    NASA Astrophysics Data System (ADS)

    Held, Karsten

    2015-03-01

    Modern computational tools such as density functional theory and its merger with dynamical mean field theory are nowadays inevitable for the modeling and understanding of oxides, their heterostructures and surfaces. In this talk, I will concentrate on the impact of electric fields, how they affect the physical properties and how to make use of them. Substantial internal electric fields are created at polar surfaces, and even for an isopolar-interface the electronic reconstruction can lead to a charge transfer and hence a dipole field. Such internal fields can be employed to efficiently separate electrons and holes in a oxide solar cell. Even if the polar dipole field is compensated by a surface reconstruction, a local surface potential remains, and makes SrTiO3 (110) the arguably simplest 2 dimensional electron gas (2DEG). External electric fields, on the other hand, can trigger ``gigantic'' responses, since correlated oxides are prone to small perturbations. For example, a field effect Mott transistor can be realized in a few layers of SrVO3 with ideal on-off (metal-insulator) switching properties; and interfacing a ferroelectric, BaTiO3, plus a 2DEG with large spin-orbit coupling, BaOsO3, allows for a giant switchable Rashba effect. Support by the ERC through Grant Agreement No. 306447 is gratefully acknowledged.

  3. Tracing explosives in soil with transcriptional regulators of Pseudomonas putida evolved for responding to nitrotoluenes

    PubMed Central

    Garmendia, Junkal; De Las Heras, Aitor; Galvo, Teca Calcagno; De Lorenzo, Vctor

    2008-01-01

    Summary Although different biological approaches for detection of anti?personnel mines and other unexploded ordnance (UXO) have been entertained, none of them has been rigorously documented thus far in the scientific literature. The industrial 2,4,6 trinitrotoluene (TNT) habitually employed in the manufacturing of mines is at all times tainted with a small but significant proportion of the more volatile 2,4 dinitrotoluene (2,4 DNT) and other nitroaromatic compounds. By using mutation?prone PCR and DNA sequence shuffling we have evolved in vitro and selected in vivo variants of the effector recognition domain of the toluene?responsive XylR regulator of the soil bacterium Pseudomonas putida that responds to mono?, bi? and trinitro substituted toluenes. Re?introduction of such variants in P. putida settled the transcriptional activity of the cognate promoters (Po and Pu) as a function of the presence of nitrotoluenes in the medium. When strains bearing transcriptional fusions to reporters with an optical output (luxAB, GFP) were spread on soil spotted with nitrotoluenes, the signal triggered by promoter activation allowed localization of the target compounds on the soil surface. Our data provide a proof of concept that non?natural transcription factors evolved to respond to nitroaromatics can be engineered in soil bacteria and inoculated on a target site to pinpoint the presence of explosives. This approach thus opens new ways to tackle this gigantic humanitarian problem. PMID:21261843

  4. Why we live in the Computational Universe

    E-print Network

    Giorgio Fontana

    2006-10-19

    To better understand the deep significance of our best physical theories it could be interesting to compare our Universe with its models. It may happen that the differences between the model and reality can be made indistinguishable, to the point that it may seem acceptable to consider reality as a gigantic program, a 'mother computation' running in a Universal Computer. The computational interpretation of reality is here adopted for introducing concepts that are common in computer science, they may offer a new insight. For instance, code and memory usage optimization techniques are common in computer science because they improve the performances at a reduced hardware cost. According to the concepts discussed in this paper, the possibility of recognizing the effects of optimization rules in a physical reality will allow us to discriminate if our reality is fundamental or the result of a large computation. Conversely, code and memory optimization has side effects, if it is present in our Universe it can produce many interesting phenomena, some seem readily recognizable, others only wait to be discovered.

  5. What big eyes you have: the ecological role of giant pterygotid eurypterids

    PubMed Central

    Anderson, Ross P.; McCoy, Victoria E.; McNamara, Maria E.; Briggs, Derek E. G.

    2014-01-01

    Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi, there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night. PMID:25009243

  6. A Broad-band rupture image of the 2011 off the Pacific coast of Tohoku earthquake

    NASA Astrophysics Data System (ADS)

    Honda, R.; Yukutake, Y.; Ito, H.; Harada, M.; Aketagawa, T.; Yoshida, A.; Sakai, S.; Nakagawa, S.; Hirata, N.; Obara, K.; Kimura, H.; Matsubara, M.

    2011-12-01

    Strong ground motions from the 2011 off the Paci[|#2#|]c coast of Tohoku Earthquake, the most powerful earthquake in and around Japan after the installation of modern seismic network were recorded for more than 300 seconds by a dense and wide-span seismic network, the Metropolitan Seismic Observation Network (MeSO-net) installed around the Tokyo metropolitan area, about 200 km away from the epicenter. We investigate the rupture process of the earthquake in space and time by performing semblance enhanced stacking analysis of the waveforms in a frequency range of 0.05 to 0.5 Hz. By projecting the power of the stacked waveforms to an assumed fault plane, the rupture propagation image of the large and complex earthquake is successfully obtained. The seismic energy was mainly generated from the off shore areas of about 100 km away from the coast in Miyagi and Fukushima Prefectures. The shallow and eastern part of the fault along the Japan trench off Miyagi Prefecture released strong seismic energy which might have been related to the excitation of gigantic tsunami. In contrast, the southern shallow part of the fault plane, off Ibaraki Prefecture, released only minor seismic energy. Our analysis suggests that the focal areas combining both the of[|#2#|]cially forecasted Miyagi-oki earthquake and those of historical earthquakes that occurred off the coast of Fukushima Prefecture in 1938 were broken, resulting in the 2011 large M9 earthquake.

  7. A complex rupture image of the 2011 off the Pacific coast of Tohoku Earthquake revealed by the MeSO-net

    NASA Astrophysics Data System (ADS)

    Honda, Ryou; Yukutake, Yohei; Ito, Hiroshi; Harada, Masatake; Aketagawa, Tamotsu; Yoshida, Akio; Sakai, Shin'ichi; Nakagawa, Shigeki; Hirata, Naoshi; Obara, Kazushige; Kimura, Hisanori

    2011-07-01

    Strong ground motions from the 2011 off the Pacific coast of Tohoku Earthquake, the most powerful earthquake to have occurred in and around Japan after the installation of a modern seismic network, were recorded for more than 300 seconds by a dense and wide-span seismic network, the Metropolitan Seismic Observation Network (MeSO-net), installed around the Tokyo metropolitan area about 200 km away from the epicenter. We investigate the rupture process of the earthquake in space and time by performing semblance-enhanced stacking analysis of the waveforms in a frequency range of 0.05 to 0.5 Hz. By projecting the power of the stacked waveforms to an assumed fault plane, the rupture propagation image of the large and complex earthquake has been successfully obtained. The seismic energy was mainly generated from the off-shore areas of about 100 km away from the coast in Miyagi and Fukushima Prefectures. The shallow and eastern part of the fault along the Japan trench off Miyagi Prefecture released strong seismic energy which might have been related to the excitation of gigantic tsunami. In contrast, the southern shallow part of the fault plane, off Ibaraki Prefecture, released only minor seismic energy. Our analysis suggests that the focal areas combining both the officially-forecasted Miyagi-oki earthquake and those of historical earthquakes that occurred off the coast of Fukushima Prefecture in 1938 were broken, resulting in the 2011 great M 9 earthquake.

  8. AB Blanket for Cities (for continual pleasant weather and protection from chemical, biological and radioactive weapons)

    E-print Network

    Bolonkin, Alexander

    2009-01-01

    In a series of previous articles (see references) the author offered to cover a city or other important large installations or subregions by a transparent thin film supported by a small additional air overpressure under the form of an AB Dome. The building of a gigantic inflatable AB Dome over an empty flat surface is not difficult. However, if we want to cover a city, garden, forest or other obstacle course we cannot easily deploy the thin film over building or trees. In this article is suggested a new method which solves this problem. The idea is to design a double film blanket filled by light gas (for example, methane, hydrogen, or helium). Sections of this AB Blanket are lighter then air and fly in atmosphere. They can be made on a flat area (serving as an assembly area) and delivered by dirigible or helicopter to station at altitude over the city. Here they connect to the already assembled AB Blanket subassemblies, cover the city in an AB Dome and protect it from bad weather, chemical, biological and rad...

  9. El proyecto AUGER

    NASA Astrophysics Data System (ADS)

    Etchegoyen, A.

    Hace ya ms de 30 aos en Volcano Ranch, EE.UU., un extenso chubasco csmico (ECC) fue detectado con energa en exceso de 1020 eV. Desde entonces, observatorios ubicados en Haverah Park del Reino Unido, Yakutsk de Rusia, AGASA de Japn y Dugway de EE.UU. tambin han observado ECC con energas mayores que 1020 eV. Poco se sabe de dichos rayos, y en particular cul es la naturaleza del primario, de dnde provienen, y cmo son acelerados, pero su naturaleza ultrarelativista excluye la mayora de las respuestas dejando slo algunas plausibles de ser investigadas experimentalmente. Grupos de cientficos de 20 pases estn trabajando con el fin de construir dos arreglos de detectores gigantes, uno en cada hemisferio a lo largo de 3000 km2 c/u. Dichas dimensiones son necesarias debido al flujo estimado de 1 rayo csmico/centuria/km2/sr. La sede del Observatorio del Sur es la Argentina. El proyecto fue nombrado Pierre Auger en conmemoracin del clebre fsico francs que detect por primera vez chubascos csmicos en 1938. El proyecto focaliza su inters en rayos csmicos con energas mayores que 1020 eV.

  10. Food industry and economic development in the Asia Pacific.

    PubMed

    McKay, John

    2007-01-01

    The food industry in the Asia Pacific region is gigantic in size, and is therefore a key element in the economic development prospects for the region. It is estimated that in 2000, for example, total expenditure on food and beverages in China was worth $US 188.5 billion, second only to that in Japan at $322 billion. Yet it is clear that given the expansion of both populations and incomes in the region this market will expand rapidly over the next few years. Particularly important will be the continued growth of cities and of the share of employment in industrial and service activities. Much of this growth in food purchases will be supplied from local sources, but this will demand some fundamental changes in domestic food production systems. There will also be a substantial growth in the food trade, with ever increasing levels of national and regional specialisation. These developments will put increasing pressures on quality standards at all levels, with a growing emphasis on food safety, integrity, quality, and nutritional and health impacts. This paper reviews the current status of the food industry and the food trade in the region, and presents some projections for future developments. Particular emphasis is given to policy choices that must be made to ensure that the food system in the region develops in ways that are sustainable and most beneficial to the population as a whole. PMID:17392081

  11. Compass roses on the Book of Navigation ( Kitab-? Bahriye): Declination data source for geomagnetic field models

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ibrahim; Gullu, Mevlut; Yilmaz, Mustafa; Dereli, Mehmet A.

    2010-10-01

    The Earth is surrounded by a geomagnetic field that is generated by dynamo processes in the core like a gigantic magnet. The Earth's geomagnetic field shifts with time and location. There has been a comprehensive effort for modelling the geomagnetic field of the Earth at regional and global scales by several researchers in the recent decades. The magnetic data from historical sources have a great importance in geomagnetic field modelling. The declination was the first measured geomagnetic field element with the early use of compasses for navigation. In this study the declination values estimated from compass roses drawn on the Book of Navigation ( Kitab-? Bahriye) that are georeferenced by an artificial neural network are compared to the declination values based on the geomagnetic field models CALS3K.3 and SCHA.DIF.3K. The results show that the compass roses drawn on the portolan charts of Kitab-? Bahriye can be used as declination data sources for regional or global geomagnetic field models.

  12. Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives

    PubMed Central

    Snchez-Villagra, Marcelo R.

    2010-01-01

    The study of fossilized ontogenies in mammals is mostly restricted to postnatal and late stages of growth, but nevertheless can deliver great insights into life history and evolutionary mechanisms affecting all aspects of development. Fossils provide evidence of developmental plasticity determined by ecological factors, as when allometric relations are modified in species which invaded a new space with a very different selection regime. This is the case of dwarfing and gigantism evolution in islands. Skeletochronological studies are restricted to the examination of growth marks mostly in the cement and dentine of teeth and can provide absolute age estimates. These, together with dental replacement data considered in a phylogenetic context, provide life-history information such as maturation time and longevity. Palaeohistology and dental replacement data document the more or less gradual but also convergent evolution of mammalian growth features during early synapsid evolution. Adult phenotypes of extinct mammals can inform developmental processes by showing a combination of features or levels of integration unrecorded in living species. Some adult features such as vertebral number, easily recorded in fossils, provide indirect information about somitogenesis and hox-gene expression boundaries. Developmental palaeontology is relevant for the discourse of ecological developmental biology, an area of research where features of growth and variation are fundamental and accessible among fossil mammals. PMID:20071389

  13. Inhomogeneous and nonstationary Hall states of the CDW with quantized normal carriers

    NASA Astrophysics Data System (ADS)

    Brazovskii, S.

    2015-03-01

    We suggest a theory for a deformable and sliding charge density wave (CDW) in the Hall bar geometry for the quantum limit when the carriers in remnant small pockets are concentrated at lowest Landau levels (LL) forming a fractionally (? < 1) filled quantum Hall state. The gigantic polarizability of the CDW allows for a strong redistribution of electronic densities up to a complete charge segregation when all carriers occupy, with the maximum filling, a fraction ? of the chain length - thus forming the integer quantum Hall state, while leaving the fraction (1 - ?) of the chain length unoccupied. The electric field in charged regions easily exceeds the pinning threshold of the CDW, then the depinning propagates into the nominally pinned central region via sharp domain walls. Resulting picture is that of compensated collective and normal pulsing counter-currents driven by the Hall voltage. This scenario is illustrated by numerical modeling for nonstationary distributions of the current and the electric field. This picture can interpret experiments in mesa-junctions showing depinning by the Hall voltage and the generation of voltage-controlled high frequency oscillations (Yu.I. Latyshev, P. Monceau, A.A. Sinchenko, et al., Presented at ECRYS-2011, unpublished [1]).

  14. Effect of seasonal changes on content and profile of soluble carbohydrates in tubers of different varieties of Jerusalem artichoke (Helianthus tuberosus L.).

    PubMed

    Kocsis, Laura; Liebhard, Peter; Praznik, Werner

    2007-11-14

    A high content (60-65% of dry mass DM) of water soluble carbohydrates was found in early harvested varieties (Bella and Bianka) and middle early varieties (Topstar and Gigant) harvested 22-25 weeks after plantation. In late varieties (Waldspindel, Violet de Rennes, Rote Zonenkugel) a similar amount was obtained (55-60% of DM) when harvested 29-33 weeks after planting. There was a distinctive impact on maturing process as well as frost period alterations which resulted in conversion of high polymer inulin to low polymer inulin as well as to sucrose. In early/middle early varieties a correlation between sucrose and inulin level (r = - 0.952**) with a linear regression of y = - 1.35x + 62.32 was observed, whereas the dpn of inulin decreased from 12-14 to 6-8. In late cultivars this correlation was not as exact (r = - 0.502**); dpn of inulin decreased from 12-16 to 7-10. This knowledge about carbohydrate profiles for different varieties of Jerusalem artichoke offers the possibility of selecting suitable cultivars and deciding the appropriate harvest time for an optimum processing of tubers for their application as prebiotic and novel food component. PMID:17941691

  15. Highly viscous liquid crystalline mixtures: the alternative to liquid crystalline elastomers

    NASA Astrophysics Data System (ADS)

    Shibaev, Petr; Schlesier, Cristina; Newman, Leah; McDonald, Scott

    2012-02-01

    Novel highly viscous liquid crystalline materials based on mixtures of glass forming oligomers and low molar mass liquid crystals were recently designed [1, 2] and studied. In this communication the novel data are presented, the analysis and discussion are extended. It is shown that viscoelastic properties of the materials are due to the physical entanglements between cyclic oligomers and low molar mass mesogens, not due to the chemical crosslinks between molecular moities. However, the mechanical properties of these viscoelastic materials resemble those of chemically crosslinked elastomers (elasticity and reversibility of deformations). The properties of chiral and non-chiral materials loaded with ferromagnetic nanoparticles are discussed in detail. Cholesteric materials undergo gigantic color changes in the wide spectral range under the deformation that allows distant detection of deformation and determination the anisotropy of deformation and its type. The materials doped with laser dyes become mechanically tunable lasers themselves and emit coherent light while pumped by external laser. A simple model is suggested to account for the observed effects; physical properties of the novel materials and liquid crystalline elastomers are compared and discussed. [4pt] [1] P.V. Shibaev, C. Schlesier, R. Uhrlass, S. Woodward, E. Hanelt, Liquid Crystals, 37:12, 1601-1604 [0pt] [2] P.V. Shibaev, P. Riverra, D. Teter, S. Marsico, M. Sanzari, V. Ramakrishnan, E. Hanelt, Optics Express, 16, 2965 (2008)

  16. Improved heat exhaust and the characteristics of the high Tc superconducting terahertz emitter

    NASA Astrophysics Data System (ADS)

    Kashiwagi, T.; Yamamoto, T.; Kitamura, T.; Asanuma, K.; Yasui, T.; Shibano, Y.; Watanabe, C.; Nakade, K.; Saiwai, Y.; Kubo, H.; Sakamoto, K.; Katsuragawa, T.; Tsujimoto, M.; Yoshizaki, R.; Minami, H.; Klemm, R. A.; Kadowaki, K.

    2015-03-01

    In our previous study it is known that THz emitting efficiency improves greatly when the stand-alone type of mesa structure is used for the THz emitting device. The principle reason for that lies in the heat removal from the mesa, in which a gigantic amount of heat is generated while the mesa is in the resistive state. Recently, we developed a new device structure based on the stand-alone type of mesa structure of Bi2212 single crystal in order to make high exhaust of Joule heating. The results show that although the power is comparable and is not significantly increased, very wide the radiation frequencies ranging from 0.3 to 1.6 THz were obtained. We will discuss the details of the radiation characteristics of this one. This study has been supported by CREST-JST. TK is also supported by the Matsuda grant and JST A-STEP. This work is in part performed in collaboration with Dr. Wai Kwok and his group in Argonne National Lab.

  17. Mechanical implications of pneumatic neck vertebrae in sauropod dinosaurs

    PubMed Central

    Schwarz-Wings, Daniela; Meyer, Christian A.; Frey, Eberhard; Manz-Steiner, Hans-Rudolf; Schumacher, Ralf

    2010-01-01

    The pre-sacral vertebrae of most sauropod dinosaurs were surrounded by interconnected, air-filled diverticula, penetrating into the bones and creating an intricate internal cavity system within the vertebrae. Computational finite-element models of two sauropod cervical vertebrae now demonstrate the mechanical reason for vertebral pneumaticity. The analyses show that the structure of the cervical vertebrae leads to an even distribution of all occurring stress fields along the vertebrae, concentrated mainly on their external surface and the vertebral laminae. The regions between vertebral laminae and the interior part of the vertebral body including thin bony struts and septa are mostly unloaded and pneumatic structures are positioned in these regions of minimal stress. The morphology of sauropod cervical vertebrae was influenced by strongly segmented axial neck muscles, which require only small attachment areas on each vertebra, and pneumatic epithelia that are able to resorb bone that is not mechanically loaded. The interaction of these soft tissues with the bony tissue of the vertebrae produced lightweight, air-filled vertebrae in which most stresses were borne by the external cortical bone. Cervical pneumaticity was therefore an important prerequisite for neck enlargement in sauropods. Thus, we expect that vertebral pneumaticity in other parts of the body to have a similar role in enabling gigantism. PMID:19801376

  18. Identification and Genetic Variation of Fasciola Species from Tabriz, North- Western Iran

    PubMed Central

    Shahbazi, A; Akbarimoghaddam, M; Izadi, S; Ghazanchaii, A; Jalali, N; Bazmani, A

    2011-01-01

    Background Fascioliasis is considered as the most important helminthic infection of cattle and sheep. Traditional approaches using morphological and biologic characters cannot cause a certainty in the accurate and precise identification and intra-specific differences of Fasciola spp. In this study, we identified Fasciola species using ITS-1 marker and described genetic variation of each species of the parasite in isolates from Tabriz slaughterhouse in West Azerbaijan Province, north- western Iran. Methods Overall, 100 samples (50 from sheep and 50 from cattle) morphologically detected as Fasciola worms were studied for identification of Fasciola species by PCR-RFLP method and intra-species variation of the parasite using RAPD-PCR technique. Results A region of approximately 460bp in all samples was successfully amplified. There were no identifiable variations among the size of PCR products. Two and three fragments in samples correspond to F. hepatica and F. gigantica was seen, respectively, through PCR-RFLP method. No difference was seen in digestion pattern according to host (sheep or cattle). Different types of each species of the parasite was observed using RAPD-PCR technique. Conclusion We could have an estimate of frequency of F. hepatica and F. gigantic and different genotypes of the parasite in isolates from one locality in north- western of Iran. By extension of such studies in future to other animal hosts (buffalo and goat) and including more regions to sampling, the reliability of the results and their application for control programs in zoonotic diseases will be increased. PMID:22347297

  19. Study of Historical 4B/X17 Mega Flare on 28 October 2003 (P58)

    NASA Astrophysics Data System (ADS)

    Uddin, W.; Chandra, R.; Ali, S. S.

    2006-11-01

    wuddin_99@yahoo.com We analysed multi-wavelength data of 28 October 2003 4B/X17.2 class extremely energetic parallel ribbon solar flare, which occurred in NOAA 10486. The flare was well observed in H-alpha at ARIES, Nainital and various space (SOHO, TRACE, RHESSI, WIND etc.) and ground based Observatories. The H-alpha observations show the stretching/detwisting and eruption of helically twisted S shaped (sigmoid) filament in the South-West direction of the active region with bright shock front followed by rapid increase in intensity and area of the gigantic flare. The flare is associated with a bright/fast full halo earth directed CME, strong type II, III and IV radio bursts, an intense proton event and GLE. It seems that the filament eruption triggered the halo CME because the helical structure is clearly visible in the SOHO/LASCO C2, C3 images. This indicates helicity transfer from chromosphere to corona and interplanetary medium. The magnetic field of the flaring region was most complex with high magnetic shear. From the above analysis we feel that the energy buildup/release process of this unique flare support helically twisted magnetic flux rope model.

  20. Catastrophic flood origin, little Missouri River valley, Montana, South Dakota, and North Dakota

    SciTech Connect

    Clausen, E.N.

    1988-07-01

    Mosaics of photographically reduced topographic maps demonstrate the Little Missouri River valley was developed by gigantic floods. Catastrophic flood landforms, oriented in a northwest-southeast direction, cross the entire Little Missouri drainage basin. Field evidence, consisting of abundant flood-deposited alluvium, supports map evidence. Flood-produced landforms, cut in easily eroded claystone bedrock, appear fresh, suggesting that floods occurred late during the last glacial cycle. Sheets of water, several hundred kilometers wide, flowed in a southeast direction, parallel with a continental ice margin. Erosion lowered the regional surface from a level corresponding to the tops of the highest present-day buttes to the surface now crossed by the headwaters of the Moreau, Grand, Cannonball, Heart, and Green Rivers. Spillway trenches served to channel flow and rapidly cut headward into easily eroded claystone. These trenches include the Moreau, Grand, Cannonball, Heart, and Missouri valleys. The Missouri valley in western North Dakota became the dominant spillway as tributary trenches systematically cut off flow feeding competing spillways. Formation of the Little Missouri spillway, first as a north-trending valley, progressively cut off floodwaters flowing into the Heart, Cannonball, Grand, and Moreau spillways. The north end of the Little Missouri spillway also was cut off by a deeper east-trending spillway. Huge sheets of floodwater continued to pour across the divide west of the Little Missouri continuing to lower that surface. These floodwaters were cut off by development of the Yellowstone spillway in eastern Montana.

  1. Solitary ganglioneuromatosis of the descending colon, presenting as giant retroperitoneal tumour.

    PubMed

    Mate?, In; Iosif, C; Dinu, D; Constantinoiu, S

    2013-01-01

    Ganglioneuroma (GN) is a benign neoplasia of the autonomous nervous system, colonic GN is uncommon in adults. There are three subgroups: polypoid GN, ganglioneuromatous polyposis and diffuse ganglioneuromatosis. Ganglioneuromatosis is highly-associated to neurofibromatosis type 1 (NF1) and multiple endocrine neoplasia type 2b (MEN2B). A 68-year-old female, with a discrete retarded emission of stools, was admitted for a large tumor in the left flank; CT scan, urography and barium enema demonstrated a large retroperitoneal mass, presumed as sarcoma. Open surgery discovered a 16 10 11 cm solid and encapsulated tumor, attached to the retroperitoneal descending colon, with no macroscopic mucosal involvement; the pathologic diagnosis of the resected specimen (en-bloc tumorectomy with limited colectomy) was intramural colonic ganglio-neuromatosis. Anamnesis, physical examination and complete endoscopic explorations showed no evidence of personal bearing or familial aggregation of genetic syndromes. In adults, association of transmural ganglioneuromatosis to NF1 or MEN2B is not mandatory; presentation often mimics obstructive carcinoma and positive diagnosis is provided by pathological examination of the resected specimen. In this peculiar case, the loose tissue of the retroperitoneal space favoured a slow development of intramural ganglioneuromatosis, presenting as a gigantic retroperitoneal mass with no radiological evidence of its colonic origin. PMID:23958108

  2. A transparently scalable visualization architecture for exploring the universe.

    PubMed

    Fu, Chi-Wing; Hanson, Andrew J

    2007-01-01

    Modern astronomical instruments produce enormous amounts of three-dimensional data describing the physical Universe. The currently available data sets range from the solar system to nearby stars and portions of the Milky Way Galaxy, including the interstellar medium and some extrasolar planets, and extend out to include galaxies billions of light years away. Because of its gigantic scale and the fact that it is dominated by empty space, modeling and rendering the Universe is very different from modeling and rendering ordinary three-dimensional virtual worlds at human scales. Our purpose is to introduce a comprehensive approach to an architecture solving this visualization problem that encompasses the entire Universe while seeking to be as scale-neutral as possible. One key element is the representation of model-rendering procedures using power scaled coordinates (PSC), along with various PSC-based techniques that we have devised to generalize and optimize the conventional graphics framework to the scale domains of astronomical visualization. Employing this architecture, we have developed an assortment of scale-independent modeling and rendering methods for a large variety of astronomical models, and have demonstrated scale-insensitive interactive visualizations of the physical Universe covering scales ranging from human scale to the Earth, to the solar system, to the Milky Way Galaxy, and to the entire observable Universe. PMID:17093340

  3. History of rocketry in India

    NASA Astrophysics Data System (ADS)

    Vasant, Gowarikar; Suresh, B. N.

    2009-12-01

    The Indian Space programme took birth on November 21, 1963, with the launch of Nike-Apache, an American sounding rocket from the shores of Thumba near Thiruvananthapuram on the west coast of India. From a family of operational sounding rockets known as the Rohini Sounding Rockets, India's launch vehicles have now grown up through SLV-3 and Augmented Satellite Launch Vehicle (ASLV) to the current gigantic satellite launchers, PSLV and Geosynchronous Satellite Launch Vehicle (GSLV). Though we had failures in the initial launches of SLV-3, ASLV and PSLV, these failures gave Indian Space Research Organisation (ISRO) a thorough and in depth understanding of the nuances of launch vehicle technology that later led to successful missions. An entirely new dimension was added to the Indian space programme when a space capsule was recovered very precisely after it had orbited the Earth for 12 days. The future for launch vehicles in ISRO looks bright with the GSLV MKIII, which is currently under development and the pursuit of cutting edge technologies such as reusable launch vehicles and air-breathing propulsion.

  4. The Revival of White Holes as Small Bangs

    E-print Network

    Alon Retter; Shlomo Heller

    2011-07-17

    Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed.

  5. Before the Giants: APASS Support to Ambitious Ground-based Galaxy Investigations and Space Missions Serching for Exo-Earths (Abstract)

    NASA Astrophysics Data System (ADS)

    Munari, U.

    2015-06-01

    (Abstract only) A huge, worldwide effort is underway to reconstruct the structure, kinematics and evolution of our Galaxy with optical spectroscopic techniques, which provide radial velocities and individual chemical abundances in addition to derive fundamental stellar parameters like surface temperature and gravity. RAVE has used for ten years (20032013) the 6dF 150-fiber positioner at the 1.3-meter UK Schmidt telescope in Siding Spring, ESO-Gaia has hundreds of nights allocated at the VLT telescopes in Chile with UVES and GIRAFFE multi-fiber instruments, GALAH has been allocated 400 nights in five years with the 400-fiber HERMES spectrograph at the 4-meter Australian telescope. Common to the millions of stars targeted by these surveys (over the range 10 < V < 16 mag) is the lack of suitable, multi-band, accurate optical photometry. In this talk, I review the fundamental role played by APASS in providing such missing photometric information for the stars targeted by these gigantic spectroscopic surveys. The APASS BVgri data are fundamental to support the spectroscopic effort, for example to constrain (when modelled together with 2MASS infrared JHK photometry) the stellar temperature. The APASS data are also crucial in fixing the interstellar reddening and the distance to the target stars, and their importance will be further expanded when APASS ultraviolet (u) and far red (z,Y) magnitudes will become available, as well the unsaturated APASS extension to brighter stars so that most of the bright spectroscopic standards will become within photometric reach.

  6. Choosing Between Yeast and Bacterial Expression Systems: Yield Dependent

    NASA Technical Reports Server (NTRS)

    Miller, Rebecca S.; Malone, Christine C.; Moore, Blake P.; Burk, Melissa; Crawford, Lisa; Karr, Laurel J.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Green fluorescent protein (GFP) is a naturally occurring fluorescent protein isolated from the jellyfish Aequorea victoria. The intrinsic fluorescence of the protein is due to a chromophore located in the center of the molecule. Its usefulness has been established as a marker for gene expression and localization of gene products. GFP has recently been utilized as a model protein for crystallization studies at NASA/MSFC, both in earth-based and in microgravity experiments. Because large quantities of purified protein were needed, the cDNA of GFP was cloned into the Pichia pastoris pPICZ(alpha) C strain, with very little protein secreted into the media. Microscopic analysis prior to harvest showed gigantic green fluorescent yeast, but upon harvesting most protein was degraded. Trial fermentations of GFP cloned into pPICZ A for intracellular expression provided unsatisfactory yield. GFP cloned into E, coli was overexpressed at greater than 150 mg/liter, with purification yields at greater than 100mg/liter.

  7. Metal enrichment in the Fermi bubbles as a probe of their origin

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Nakashima, Shinya; Tahara, Masaya; Kataoka, Jun; Totani, Tomonori; Fujita, Yutaka; Sofue, Yoshiaki

    2015-06-01

    The Fermi bubbles are gigantic gamma-ray structures in our Galaxy. The physical origin of the bubbles is still under debate. The leading scenarios can be divided into two categories. One is nuclear star-forming activity similar to extragalactic starburst galaxies and the other is past active galactic nucleus (AGN)-like activity of the Galactic center supermassive black hole. In this letter, we propose that metal abundance measurements will provide an important clue to probe their origin. Based on a simple spherically symmetric bubble model, we find that the generated metallicity and abundance patterns of the bubbles' gas strongly depend on assumed star formation or AGN activities. Star formation scenarios predict higher metallicities and abundance ratios of [O/Fe] and [Ne/Fe] than AGN scenarios do because of supernovae ejecta. Furthermore, the resultant abundance depends on the gamma-ray emission process because different mass injection histories are required for the different gamma-ray emission processes due to the acceleration and cooling time scales of non-thermal particles. Future X-ray missions such as ASTRO-H and Athena will give a clue to probe the origin of the bubbles through abundance measurements with their high energy resolution instruments.

  8. ADELE sensitivity to high-energy radiation from transient luminous events during the Hurricane and Severe Storm Sentinels campaigns

    NASA Astrophysics Data System (ADS)

    Bowers, G.; Smith, D. M.; Dwyer, J. R.; Cummer, S. A.; Martinez-Mckinney, F.; Kelley, N. A.; Harris, C. B.; Buzbee, P.

    2012-12-01

    In the summers of 2013 and 2014, UCSC will fly the Airborne Detector for Energetic Lightning Emissions (ADELE) instrument on board one of the Global Hawk aircraft of the NASA Hurricane and Severe Storm Sentinels (HS3) campaign over storms in the Atlantic. In addition to Terrestrial Gamma-ray Flashes (TGFs), which have been observed at gamma-ray energies by satellites such as RHESSI and FERMI, ADELE will also search for high-energy radiation from Transient Luminous Events (TLEs, i.e. elves, gigantic jets, blue jets, sprites, and sprite halos). High-energy radiation is plausible as a byproduct of stepped leaders in jets, streamers in sprites, and acceleration of electrons in the electromagnetic pulse (EMP) that produces elves. Because ADELE will fly at low altitudes, the intensity of radiation from these events could be orders of magnitude higher at ADELE than at satellites in low earth orbit. We will consider the high energy spectra that might be produced by TLEs and estimate to what extent these phenomena can be observed by ADELE on HS3.

  9. A giant crocodile in the Dubois Collection from the Pleistocene of Kali Gedeh (Java).

    PubMed

    Delfino, Massimo; De Vos, John

    2014-03-01

    The fauna of the Pleistocene Homo-bearing sites of Java has been well known for more than a century. A recent revision of the crocodylian remains confirmed both the validity of Gavialis bengawanicus and the synonymization of Crocodylus ossifragus with C. siamensis. Here we report on a still unpublished crocodylian specimen collected by Eugene Dubois in the latest Early Pleistocene of Kali Gedeh that can be tentatively referred to the genus Crocodylus. The size of the specimen, the approximately 1 m long lower jaw in particular, indicated that this crocodile attained a total length of approximately 6 or 7 m. Along with specimens from the Plio-Pleistocene of Africa, this material provides evidence for gigantism in Crocodylus. It is not clear whether or not the 'temperature-size rule' applies to fossil crocodylians, but due to the growing interest in predicting future temperature-related size changes of the extant organisms, it would be interesting to study in detail the past reaction to temperature changes of crocodylians and other terrestrial ectothermic animals. PMID:24673759

  10. Resection of a giant bilateral retrovascular intrathoracic goiter causing severe upper airway obstruction, 2 years after subtotal thyroidectomy: a case report and review of the literature

    PubMed Central

    Tsakiridis, Kosmas; Visouli, Aikaterini N.; Karapantzos, Elias; Mpakas, Andreas; Machairiotis, Nikolaos; Stylianaki, Aikaterini; Christofis, Christos; Katsikogiannis, Nikolaos; Courcoutsakis, Nicolaos; Zarogoulidis, Konstantinos

    2012-01-01

    The intrathoracic (or substernal) goiter is more often benign; but it can be malignant in 2-22% of patients. There is history of prior thyroid surgery in 10% to more than 30% of patients. Intrathoracic goiters cause adjacent structure compression more frequently than the cervical goiters, due to the limited space of the thoracic cage. Compression of trachea, oesophagus, vascular and neural structures may cause dyspnoea, dysphagia, superior vena cava syndrome, subclavian vein thrombosis, hoarseness, and Horners syndrome. There is usually progressive deterioration, but acute exacerbation may occur. The presence of a thoracic goiter (>50% of the mass below the thoracic inlet) is per se an indication for resection. Tracheal compression by (cervical or thoracic) goiter is also an indication for resection; early tracheal decompression is recommended particularly in symptomatic patients. In severe respiratory distress, intubation and semi-urgent operation may be required. With early intervention, most intrathoracic goiters can be removed through a cervical approach, while tracheomalacia is avoided. We hereby present successful and uncomplicated total thyroidectomy, through a median sternotomy, of a benign, gigantic, bilateral, retrovascular, posterior mediastinal, intrathoracic goiter, encircling the trachea, and causing severe respiratory distress in a 63 year old man with history of previous subtotal thyroidectomy. PMID:23304440

  11. A vision of the environmental and occupational noise pollution in Malaysia.

    PubMed

    Yuen, Foo Keng

    2014-01-01

    Environmental noise remains a complex and fragmented interplay between industrialization, population growth, technological developments, and the living environment. Next to the circulatory diseases and cancer, noise pollution has been cited as the third epidemic cause of psychological and physiological disorders internationally. A reliable and firm relationship between the cumulative health implications with the traffic annoyance and occupational noise has been established. This agenda has called for an integrated, coordinated, and participatory approach to the reliable protection of noise interference. Despite several fragmented policies, legislation and global efforts have been addressed; the noise pollution complaints have been traditionally neglected in developing countries, especially in Malaysia. This paper was undertaken to postulate an initial platform to address the dynamic pressures, gigantic challenges, and tremendous impacts of noise pollution scenario in Malaysia. The emphasis is speculated on the traffic interference and assessment of industrial and occupational noise. The fundamental importance of noise monitoring and modeling is proposed. Additionally, the confronting conservation program and control measure for noise pollution control are laconically elucidated. PMID:25387540

  12. Wafer-scale metasurface for total power absorption, local field enhancement and single molecule Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Dongxing; Zhu, Wenqi; Best, Michael D.; Camden, Jon P.; Crozier, Kenneth B.

    2013-10-01

    The ability to detect molecules at low concentrations is highly desired for applications that range from basic science to healthcare. Considerable interest also exists for ultrathin materials with high optical absorption, e.g. for microbolometers and thermal emitters. Metal nanostructures present opportunities to achieve both purposes. Metal nanoparticles can generate gigantic field enhancements, sufficient for the Raman spectroscopy of single molecules. Thin layers containing metal nanostructures (``metasurfaces'') can achieve near-total power absorption at visible and near-infrared wavelengths. Thus far, however, both aims (i.e. single molecule Raman and total power absorption) have only been achieved using metal nanostructures produced by techniques (high resolution lithography or colloidal synthesis) that are complex and/or difficult to implement over large areas. Here, we demonstrate a metasurface that achieves the near-perfect absorption of visible-wavelength light and enables the Raman spectroscopy of single molecules. Our metasurface is fabricated using thin film depositions, and is of unprecedented (wafer-scale) extent.

  13. Wafer-scale metasurface for total power absorption, local field enhancement and single molecule Raman spectroscopy

    PubMed Central

    Wang, Dongxing; Zhu, Wenqi; Best, Michael D.; Camden, Jon P.; Crozier, Kenneth B.

    2013-01-01

    The ability to detect molecules at low concentrations is highly desired for applications that range from basic science to healthcare. Considerable interest also exists for ultrathin materials with high optical absorption, e.g. for microbolometers and thermal emitters. Metal nanostructures present opportunities to achieve both purposes. Metal nanoparticles can generate gigantic field enhancements, sufficient for the Raman spectroscopy of single molecules. Thin layers containing metal nanostructures (metasurfaces) can achieve near-total power absorption at visible and near-infrared wavelengths. Thus far, however, both aims (i.e. single molecule Raman and total power absorption) have only been achieved using metal nanostructures produced by techniques (high resolution lithography or colloidal synthesis) that are complex and/or difficult to implement over large areas. Here, we demonstrate a metasurface that achieves the near-perfect absorption of visible-wavelength light and enables the Raman spectroscopy of single molecules. Our metasurface is fabricated using thin film depositions, and is of unprecedented (wafer-scale) extent. PMID:24091825

  14. Live birth in Cretaceous marine lizards (mosasauroids).

    PubMed Central

    Caldwell, M W; Lee, M S

    2001-01-01

    Although live-bearing (viviparity) has evolved around 100 times within reptiles, evidence of it is almost never preserved in the fossil record. Here, we report viviparity in mosasauroids, a group of Cretaceous marine lizards. This is the only known fossil record of live-bearing in squamates (lizards and snakes), and might represent the oldest occurrence of the trait in this diverse group; it is also the only known fossil record of viviparity in reptiles other than ichthyosaurs. An exceptionally preserved gravid female of the aigialosaur Carsosaurus (a primitive mosasauroid) contains at least four advanced embryos distributed along the posterior two-thirds of the long trunk region (dorsal vertebrae 9-21). Their orientation suggests that they were born tail-first (the nostrils emerging last) to reduce the possibility of drowning, an adaptation shared with other highly aquatic amniotes such as cetaceans, sirenians and ichthyosaurs; the orientation of the embryos also suggests that they were not gut contents because swallowed prey are usually consumed head-first. One embryo is located within the pelvis, raising the possibility that the adult died during parturition. Viviparity in early medium-sized amphibious aigialosaurs may have freed them from the need to return to land to deposit eggs, and permitted the subsequent evolution of gigantic totally marine mosasaurs. PMID:11747556

  15. Diagnosing Sotos syndrome in the setting of global developmental delay and macrocephaly.

    PubMed

    Srour, Myriam; Mazer, Barbara; Shevell, Michael I

    2006-04-01

    Sotos syndrome (cerebral gigantism) is characterized by macrocephaly, global developmental delay, characteristic facial dysmorphology, and a markedly advanced bone age. The purpose of this study was to describe the prevalence of Sotos syndrome in a consecutive series of patients with global developmental delay, which might modify our laboratory evaluation approach to this particular clinical situation. For a 10-year inclusive interval, the case records of all consecutive patients referred for global developmental delay in a single pediatric neurology practice were reviewed. Patients with macrocephaly were defined by an age- and gender-adjusted head circumference greater than or equal to the 98th percentile. Possible clinical factors associated with eventual diagnosis of Sotos syndrome in this group of macrocephalic children were tested with a two-tailed Fisher exact test. Of 261 children with global developmental delay, 18 (7%) had documented macrocephaly. Of these 18 children, 3 (17%) had an advanced bone age and were diagnosed with Sotos syndrome. In patients with global developmental delay and concomitant macrocephaly, Sotos syndrome is not uncommon. Assessment of bone age is a simple screening test for diagnosis of this entity and should be undertaken routinely in children with macrocephaly and global developmental delay even in the absence of other distinctive syndromic clinical features. PMID:16900922

  16. Linquistic geometry: new technology for decision support

    NASA Astrophysics Data System (ADS)

    Stilman, Boris; Yakhnis, Vladimir

    2003-09-01

    Linguistic Geometry (LG) is a revolutionary gaming approach which is ideally suited for military decision aids for Air, Ground, Naval, and Space-based operations, as well guiding robotic vehicles and traditional entertainment games. When thinking about modern or future military operations, the game metaphor comes to mind right away. Indeed, the air space together with the ground and seas may be viewed as a gigantic three-dimensional game board. Refining this picture, the LG approach is capable of providing an LG hypergame, that is, a system of multiple concurrent interconnected multi-player abstract board games (ABG) of various resolutions and time frames reflecting various kinds of hardware and effects involved in the battlespace and the solution space. By providing a hypergame representation of the battlespace, LG already provides a significant advance in situational awareness. However, the greatest advantage of the LG approach is an ability to provide commanders of campaigns and missions with decision options resulting in attainment of the commander's intent. At each game turn, an LG decision support tool assigns the best actions to each of the multitude of battlespace actors (UAVs, bombers, cruise missiles, etc.). This is done through utilization of algorithms finding winning strategies and tactics, which are the core of the LG approach.

  17. Morphogenetic Mechanisms in the Cyclic Regeneration of Hair Follicles and Deer Antlers from Stem Cells

    PubMed Central

    Li, Chunyi; McMahon, Chris

    2013-01-01

    We have made comparisons between hair follicles (HFs) and antler units (AUs)two seemingly unrelated mammalian organs. HFs are tiny and concealed within skin, whereas AUs are gigantic and grown externally for visual display. However, these two organs share some striking similarities. Both consist of permanent and cyclic/temporary components and undergo stem-cell-based organogenesis and cyclic regeneration. Stem cells of both organs reside in the permanent part and the growth centres are located in the temporary part of each respective organ. Organogenesis and regeneration of both organs depend on epithelial-mesenchymal interactions. Establishment of these interactions requires stem cells and reactive/niche cells (dermal papilla cells for HFs and epidermal cells for AUs) to be juxtaposed, which is achieved through destruction of the cyclic part to bring the reactive cells into close proximity to the respective stem cell niche. Developments of HFs and AUs are regulated by similar endocrine (particularly testosterone) and paracrine (particularly IGF1) factors. Interestingly, these two organs come to interplay during antlerogenesis. In conclusion, we believe that investigators from the fields of both HF and AU biology could greatly benefit from a comprehensive comparison between these two organs. PMID:24383056

  18. A possible origin of gamma rays from the Fermi Bubbles

    NASA Astrophysics Data System (ADS)

    Thoudam, Satyendra

    2014-11-01

    One of the most exciting discoveries of recent years is a pair of gigantic gamma-ray emission regions, the so-called Fermi bubbles, above and below the Galactic center. The bubbles, discovered by the Fermi space telescope, extend up to ?50 in Galactic latitude and are ?40 wide in Galactic longitude. The gamma-ray emission is also found to correlate with radio, microwave and X-rays emission. The origin of the bubbles and the associated non-thermal emissions are still not clearly understood. Possible explanations for the non-thermal emission include cosmic-ray injection from the Galactic center by high speed Galactic winds/jets, acceleration by multiple shocks or plasma turbulence present inside the bubbles, and acceleration by strong shock waves associated with the expansion of the bubbles. In this paper, I will discuss the possibility that the gamma-ray emission is produced by the injection of Galactic cosmic-rays mainly protons during their diffusive propagation through the Galaxy. The protons interact with the bubble plasma producing ?-decay gamma rays, while at the same time, radio and microwave synchrotron emissions are produced by the secondary electrons/positrons resulting from the ? decays.

  19. Rifting, recurrent landsliding and Miocene structural reorganization on NW-Tenerife (Canary Islands)

    NASA Astrophysics Data System (ADS)

    Walter, T. R.; Schmincke, H.-U.

    2002-08-01

    We studied mechanisms of structural destabilization of ocean island flanks by considering the linkage between volcano construction and volcano destruction, exemplified by the composite Teno shield volcano on Tenerife (Canary Islands). During growth, Tenerife episodically experienced giant landslides, genetically associated with rifting and preferentially located between two arms of a three-armed rift system. The deeply eroded late Miocene Teno massif allows insights into the rifting processes, the failure mechanisms and related structures. The semicircular geometry of palaeo-scarps and fracture systems, breccia deposits and the local dike swarm reconfigurations delineate two clear landslide scarp regions. Following an earlier collapse of the older Los Gigantes Formation to the north, the rocks around the scarp became fractured and intruded by dikes. Substantial lava infill and enduring dike emplacement increased the load on the weak scarp and forced the flank to creep again, finally resulting in the collapse of the younger Carrizales Formation. Once more, the changing stress field caused deformation of the nearby rocks, a fracture belt formed around the scarp and dikes intruded into new (concentric) directions. The outline, size and direction of the second failed flank of Teno very much resembles the first collapse. We suggest structural clues concerning mechanisms of recurrent volcano flank failure, verifying the concept that volcano flanks that have failed are prone to collapse again with similar dimensions.

  20. Sinbase: an integrated database to study genomics, genetics and comparative genomics in Sesamum indicum.

    PubMed

    Wang, Linhai; Yu, Jingyin; Li, Donghua; Zhang, Xiurong

    2015-01-01

    Sesame (Sesamum indicum L.) is an ancient and important oilseed crop grown widely in tropical and subtropical areas. It belongs to the gigantic order Lamiales, which includes many well-known or economically important species, such as olive (Olea europaea), leonurus (Leonurus japonicus) and lavender (Lavandula spica), many of which have important pharmacological properties. Despite their importance, genetic and genomic analyses on these species have been insufficient due to a lack of reference genome information. The now available S. indicum genome will provide an unprecedented opportunity for studying both S. indicum genetic traits and comparative genomics. To deliver S. indicum genomic information to the worldwide research community, we designed Sinbase, a web-based database with comprehensive sesame genomic, genetic and comparative genomic information. Sinbase includes sequences of assembled sesame pseudomolecular chromosomes, protein-coding genes (27,148), transposable elements (372,167) and non-coding RNAs (1,748). In particular, Sinbase provides unique and valuable information on colinear regions with various plant genomes, including Arabidopsis thaliana, Glycine max, Vitis vinifera and Solanum lycopersicum. Sinbase also provides a useful search function and data mining tools, including a keyword search and local BLAST service. Sinbase will be updated regularly with new features, improvements to genome annotation and new genomic sequences, and is freely accessible at http://ocri-genomics.org/Sinbase/. PMID:25480115

  1. Earth After the Moon Forming Impact

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin

    2006-01-01

    The Hadean Earth is widely and enduringly pictured as a world of exuberant volcanism, exploding meteors, huge craters, infernal heat, and billowing sulfurous steams; i.e., a world of fire and brimstone punctuated with blows to the head. In the background the Moon looms gigantic in the sky. The popular image has given it a name that celebrates our mythic roots. A hot early Earth is an inevitable consequence of accretion. The Moon-forming impact ensured that Earth as we know it emerged from a fog of silicate vapor. The impact separated the volatiles from the silicates. It took -100 years to condense and rain out the bulk of the vaporized silicates, although relatively volatile elements may have remained present in the atmosphere throughout the magma ocena stage. The magma ocean lasted approx. 2 Myr, its lifetime prolonged by tidal heating and thermal blanketing by a thick (CO2-rich steam atmosphere. Water oceans condensed quickly after the mantle solidified, but for some 10-100 Myr the surface would have stayed warm (approx. 500 K) until the CO2 was removed into the mantle. Thereafter the faint young Sun suggests that a lifeless Earth would always have been evolving toward a bitterly cold ice world, but the cooling trend was frequently interrupted by volcanic or impact induced thaws.

  2. Isolation and characterization of a novel herpesvirus from a free-ranging eastern grey kangaroo (Macropus giganteus).

    PubMed

    Vaz, Paola Karinna; Motha, Julian; McCowan, Christina; Ficorilli, Nino; Whiteley, Pam Lizette; Wilks, Colin Reginald; Hartley, Carol Anne; Gilkerson, James Rudkin; Browning, Glenn Francis; Devlin, Joanne Maree

    2013-01-01

    We isolated a macropodid herpesvirus from a free-ranging eastern grey kangaroo (Macropus giganteous) displaying clinical signs of respiratory disease and possibly neurologic disease. Sequence analysis of the herpesvirus glycoprotein G (gG) and glycoprotein B (gB) genes revealed that the virus was an alphaherpesvirus most closely related to macropodid herpesvirus 2 (MaHV-2) with 82.7% gG and 94.6% gB amino acid sequence identity. Serologic analyses showed similar cross-neutralization patterns to those of MaHV-2. The two viruses had different growth characteristics in cell culture. Most notably, this virus formed significantly larger plaques and extensive syncytia when compared with MaHV-2. No syncytia were observed for MaHV-2. Restriction endonuclease analysis of whole viral genomes demonstrated distinct restriction endonuclease cleavage patterns for all three macropodid herpesviruses. These studies suggest that a distinct macropodid alphaherpesvirus may be capable of infecting and causing disease in eastern grey kangaroos. PMID:23307380

  3. Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity

    PubMed Central

    Marx, Felix G.; Fordyce, R. Ewan

    2015-01-01

    A new, fully dated total-evidence phylogeny of baleen whales (Mysticeti) shows that evolutionary phases correlate strongly with Caenozoic modernization of the oceans and climates, implying a major role for bottom-up physical drivers. The phylogeny of 90 modern and dated fossil species suggests three major phases in baleen whale history: an early adaptive radiation (3630?Ma), a shift towards bulk filter-feeding (3023?Ma) and a climate-driven diversity loss around 3?Ma. Evolutionary rates and disparity were high following the origin of mysticetes around 38?Ma, coincident with global cooling, abrupt Southern Ocean eutrophication and the development of the Antarctic Circumpolar Current (ACC). Subsequently, evolutionary rates and disparity fell, becoming nearly constant after approximately 23?Ma as the ACC reached its full strength. By contrast, species diversity rose until 15?Ma and then remained stable, before dropping sharply with the onset of Northern Hemisphere glaciation. This decline coincided with the final establishment of modern mysticete gigantism and may be linked to glacially driven variability in the distribution of shallow habitats or an increased need for long-distance migration related to iron-mediated changes in glacial marine productivity.

  4. Creating the brain and interacting with the brain: an integrated approach to understanding the brain.

    PubMed

    Morimoto, Jun; Kawato, Mitsuo

    2015-03-01

    In the past two decades, brain science and robotics have made gigantic advances in their own fields, and their interactions have generated several interdisciplinary research fields. First, in the 'understanding the brain by creating the brain' approach, computational neuroscience models have been applied to many robotics problems. Second, such brain-motivated fields as cognitive robotics and developmental robotics have emerged as interdisciplinary areas among robotics, neuroscience and cognitive science with special emphasis on humanoid robots. Third, in brain-machine interface research, a brain and a robot are mutually connected within a closed loop. In this paper, we review the theoretical backgrounds of these three interdisciplinary fields and their recent progress. Then, we introduce recent efforts to reintegrate these research fields into a coherent perspective and propose a new direction that integrates brain science and robotics where the decoding of information from the brain, robot control based on the decoded information and multimodal feedback to the brain from the robot are carried out in real time and in a closed loop. PMID:25589568

  5. A New Azhdarchid Pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: Implications for Azhdarchid Diversity and Distribution

    PubMed Central

    Vremir, Mtys; Kellner, Alexander W. A.; Naish, Darren; Dyke, Gareth J.

    2013-01-01

    We describe a new taxon of medium-sized (wing span ca. 3 m) azhdarchid pterosaur from the Upper Cretaceous Transylvanian Basin (Sebe? Formation) of Romania. This specimen is the most complete European azhdarchid yet reported, comprising a partially articulated series of vertebrae and associated forelimb bones. The new taxon is most similar to the Central Asian Azhdarcho lancicollis Nessov but possesses a suite of autapomorphies in its vertebrae that include the relative proportions of cervicals three and four and the presence of elongated prezygapophyseal pedicles. The new taxon is interesting in that it lived contemporaneously with gigantic forms, comparable in size to the famous Romanian Hatzegopteryx thambema. The presence of two distinct azhdarchid size classes in a continental depositional environment further strengthens suggestions that these pterosaurs were strongly linked to terrestrial floodplain and wooded environments. To support this discussion, we outline the geological context and taphonomy of our new specimen and place it in context with other known records for this widespread and important Late Cretaceous pterosaurian lineage. PMID:23382886

  6. Giant lizards occupied herbivorous mammalian ecospace during the Paleogene greenhouse in Southeast Asia

    PubMed Central

    Head, Jason J.; Gunnell, Gregg F.; Holroyd, Patricia A.; Hutchison, J. Howard; Ciochon, Russell L.

    2013-01-01

    Mammals dominate modern terrestrial herbivore ecosystems, whereas extant herbivorous reptiles are limited in diversity and body size. The evolution of reptile herbivory and its relationship to mammalian diversification is poorly understood with respect to climate and the roles of predation pressure and competition for food resources. Here, we describe a giant fossil acrodontan lizard recovered with a diverse mammal assemblage from the late middle Eocene Pondaung Formation of Myanmar, which provides a historical test of factors controlling body size in herbivorous squamates. We infer a predominately herbivorous feeding ecology for the new acrodontan based on dental anatomy, phylogenetic relationships and body size. Ranking body masses for Pondaung Formation vertebrates indicates that the lizard occupied a size niche among the larger herbivores and was larger than most carnivorous mammals. Paleotemperature estimates of Pondaung Formation environments based on the body size of the new lizard are approximately 25C higher than modern. These results indicate that competitive exclusion and predation by mammals did not restrict body size evolution in these herbivorous squamates, and elevated temperatures relative to modern climates during the Paleogene greenhouse may have resulted in the evolution of gigantism through elevated poikilothermic metabolic rates and in response to increases in floral productivity. PMID:23740779

  7. The First Freshwater Mosasauroid (Upper Cretaceous, Hungary) and a New Clade of Basal Mosasauroids

    PubMed Central

    Makdi, Lszl; Caldwell, Michael W.; ?si, Attila

    2012-01-01

    Mosasauroids are conventionally conceived of as gigantic, obligatorily aquatic marine lizards (1000s of specimens from marine deposited rocks) with a cosmopolitan distribution in the Late Cretaceous (9065 million years ago [mya]) oceans and seas of the world. Here we report on the fossilized remains of numerous individuals (small juveniles to large adults) of a new taxon, Pannoniasaurus inexpectatus gen. et sp. nov. from the Csehbnya Formation, Hungary (Santonian, Upper Cretaceous, 85.383.5 mya) that represent the first known mosasauroid that lived in freshwater environments. Previous to this find, only one specimen of a marine mosasauroid, cf. Plioplatecarpus sp., is known from non-marine rocks in Western Canada. Pannoniasaurus inexpectatus gen. et sp. nov. uniquely possesses a plesiomorphic pelvic anatomy, a non-mosasauroid but pontosaur-like tail osteology, possibly limbs like a terrestrial lizard, and a flattened, crocodile-like skull. Cladistic analysis reconstructs P. inexpectatus in a new clade of mosasauroids: (Pannoniasaurus (Tethysaurus (Yaguarasaurus, Russellosaurus))). P. inexpectatus is part of a mixed terrestrial and freshwater faunal assemblage that includes fishes, amphibians turtles, terrestrial lizards, crocodiles, pterosaurs, dinosaurs and birds. PMID:23284766

  8. Evolution of germ-line signals that regulate growth and aging in nematodes

    PubMed Central

    Patel, Mavji N.; Knight, Christopher G.; Karageorgi, Constantina; Leroi, Armand M.

    2002-01-01

    We show that a signal from the germ line represses growth in the nematode Caenorhabditis elegans. Laser-microbeam ablation of cells that give rise to the germ line causes adults to become giant. Ablation of these cells in self-sterile mutant worms also causes gigantism, suggesting that the germ line represses growth because it is the source of a growth-antagonizing signal rather than because of a sink of resources required for reproduction. The C. elegans germ line also emits a signal that represses longevity. This longevity-repressing signal requires the activity of DAF-16, a forkhead/winged-helix transcription factor, but we find that that the growth-repressing signal does not. The growth-repressing signal also does not require the activity of DBL-1, a transforming growth factor ?-related protein that promotes growth in worms. By ablating the germ-line precursors of other species of free-living nematodes, we also found that both the growth-repressing and longevity-repressing signals are evolutionarily variable. Some species have both signals; others have just one or the other. We suggest that variation in germ-line signaling contributes to body size and life-history diversity in the nematodes. PMID:11805331

  9. Origin and evolution of marginal basins of the NW Pacific: Diffuse-plate tectonic reconstructions

    E-print Network

    Xu, Junyuan; Ben-Avraham, Zvi; Yu, Ho-Shing

    2012-01-01

    Formation of the gigantic linked dextral pull-apart basin system in the NW Pacific is due to NNE- to ENE-ward motion of east Eurasia. This mainly was a response to the Indo-Asia collision which started about 50 Ma ago. The displacement of east Eurasia can be estimated using three aspects: (1) the magnitude of pull-apart of the dextral pull-apart basin system, (2) paleomagnetic data from eastern Eurasia and the region around the Arctic, and (3) the shortening deficits in the Large Tibetan Plateau. All the three aspects indicate that there was a large amount (about 1200 km) of northward motion of the South China block and compatible movements of other blocks in eastern Eurasia during the rifting period of the basin system. Such large motion of the eastern Eurasia region contradicts any traditional rigid plate tectonic reconstruction, but agrees with the more recent concepts of non-rigidity of both continental and oceanic lithosphere over geological times. Based on these estimates, the method developed for resto...

  10. Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity.

    PubMed

    Marx, Felix G; Fordyce, R Ewan

    2015-04-01

    A new, fully dated total-evidence phylogeny of baleen whales (Mysticeti) shows that evolutionary phases correlate strongly with Caenozoic modernization of the oceans and climates, implying a major role for bottom-up physical drivers. The phylogeny of 90 modern and dated fossil species suggests three major phases in baleen whale history: an early adaptive radiation (36-30?Ma), a shift towards bulk filter-feeding (30-23?Ma) and a climate-driven diversity loss around 3?Ma. Evolutionary rates and disparity were high following the origin of mysticetes around 38?Ma, coincident with global cooling, abrupt Southern Ocean eutrophication and the development of the Antarctic Circumpolar Current (ACC). Subsequently, evolutionary rates and disparity fell, becoming nearly constant after approximately 23?Ma as the ACC reached its full strength. By contrast, species diversity rose until 15?Ma and then remained stable, before dropping sharply with the onset of Northern Hemisphere glaciation. This decline coincided with the final establishment of modern mysticete gigantism and may be linked to glacially driven variability in the distribution of shallow habitats or an increased need for long-distance migration related to iron-mediated changes in glacial marine productivity. PMID:26064636

  11. Resonances and Tides in Natural Satellites Systems. (Breton Title: Ressonncias e Mars em Sistemas de Satlites Naturais.) Resonancias y Mareas en Sistemas de Satlites Naturales

    NASA Astrophysics Data System (ADS)

    Callegari, Nelson, Jr.

    2006-12-01

    In this work we describe some aspects of the dynamics of the mean-motion resonances. Emphasis to the case of resonances between regular satellites of the giant planets will be given, even so some aspects of the physics of the resonances in extra-solar planetary systems are also briefly treated. The role of the resonances in satellites systems is discussed through examples, showing how certain resonances, and its relations with the tidal dissipation effects, can be the key of the explanation of some phenomena still not explained in the Solar System. Amongst some examples we highlight the problem of the resurfacing of Enceladus, the existence of active volcanoes in Io, and the possible existence of the subsurface ocean in Europe. This work has as objective the divulgation of some topics in Celestial Mechanics and Planetary Sciences for an undergraduate public in exact sciences, as Astronomy and Physics, and not their detailed description. Neste trabalho descrevemos alguns aspectos da dinmica de ressonncias de movimentos mdios. Ser dada nfase maior ao caso de ressonncias entre satlites regulares dos planetas gigantes, embora alguns aspectos da fsica das ressonncias em sistemas planetrios extra-solares tambm sejam discutidos brevemente. A importncia do estudo de ressonncias em sistemas de satlites discutida mais detalhadamente atravs de exemplos, mostrando como certas ressonncias e suas relaes com efeitos de dissipao de mar podem ser a chave de parte da explicao de alguns fenmenos ainda no explicados no Sistema Solar. Dentre vrios exemplos destacamos o problema da remodelagem da superfcie do satlite Enceladus, a existncia de vulces ativos em Io, e a possvel existncia do oceano subterrneo em Europa. Este trabalho tem como objetivo a divulgao de alguns tpicos de Mecnica Celeste e Planetologia para um pblico de nvel de graduao em disciplinas na rea de exatas, em especial Astronomia e Fsica, e no a descrio detalhada dos conceitos aqui discutidos. Describimos en este trabajo algunos aspectos de la dinmica de resonancias de movimientos promedio. Ser dado un nfasis mayor al caso de las resonancias entre satlites regulares de los planetas gigantes, aunque tambin son discutidos brevemente algunos aspectos de la fsica de resonancias en sistemas panetarios extrasolares. La importancia del estudio de las resonancias en sistemas de satlites es discutida ms detalladamente atravs de ejemplos, mostrando cmo ciertas resonancias y los efectos de disipacin por mareas pueden ser la clave de parte de la explicacin de algunos fenmenos an no comprendidos en el Sistema Solar. Entre varios ejemplos se destacan el problema de la superficie remodelada del satlite Enceladus, la existencia de volcanes activos en Io y la posible existencia de un ocano subterrneo en Europa. Este trabajo tiene como objetivo la divulgacin de algunos tpicos en Mecnica Celeste y Planetologa para un pblico universitario de ciencias exactas, en particular Astronoma y Fsica, y no la descripcin detallada de los conceptos aqu discutidos.

  12. Shedding Light on the Cosmic Skeleton

    NASA Astrophysics Data System (ADS)

    2009-11-01

    Astronomers have tracked down a gigantic, previously unknown assembly of galaxies located almost seven billion light-years away from us. The discovery, made possible by combining two of the most powerful ground-based telescopes in the world, is the first observation of such a prominent galaxy structure in the distant Universe, providing further insight into the cosmic web and how it formed. "Matter is not distributed uniformly in the Universe," says Masayuki Tanaka from ESO, who led the new study. "In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies. The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called 'cosmic web', in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure." These filaments are millions of light years long and constitute the skeleton of the Universe: galaxies gather around them, and immense galaxy clusters form at their intersections, lurking like giant spiders waiting for more matter to digest. Scientists are struggling to determine how they swirl into existence. Although massive filamentary structures have been often observed at relatively small distances from us, solid proof of their existence in the more distant Universe has been lacking until now. The team led by Tanaka discovered a large structure around a distant cluster of galaxies in images they obtained earlier. They have now used two major ground-based telescopes to study this structure in greater detail, measuring the distances from Earth of over 150 galaxies, and, hence, obtaining a three-dimensional view of the structure. The spectroscopic observations were performed using the VIMOS instrument on ESO's Very Large Telescope and FOCAS on the Subaru Telescope, operated by the National Astronomical Observatory of Japan. Thanks to these and other observations, the astronomers were able to make a real demographic study of this structure, and have identified several groups of galaxies surrounding the main galaxy cluster. They could distinguish tens of such clumps, each typically ten times as massive as our own Milky Way galaxy - and some as much as a thousand times more massive - while they estimate that the mass of the cluster amounts to at least ten thousand times the mass of the Milky Way. Some of the clumps are feeling the fatal gravitational pull of the cluster, and will eventually fall into it. "This is the first time that we have observed such a rich and prominent structure in the distant Universe," says Tanaka. "We can now move from demography to sociology and study how the properties of galaxies depend on their environment, at a time when the Universe was only two thirds of its present age." The filament is located about 6.7 billion light-years away from us and extends over at least 60 million light-years. The newly uncovered structure does probably extend further, beyond the field probed by the team, and hence future observations have already been planned to obtain a definite measure of its size. More information This research was presented in a paper published as a letter in the Astronomy & Astrophysics Journal: The spectroscopically confirmed huge cosmic structure at z = 0.55, by Tanaka et al. The team is composed of Masayuki Tanaka (ESO), Alexis Finoguenov (Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany and University of Maryland, Baltimore, USA), Tadayuki Kodama (National Astronomical Observatory of Japan, Tokyo, Japan), Yusei Koyama (Department of Astronomy, University of Tokyo, Japan), Ben Maughan (H.H. Wills Physics Laboratory, University of Bristol, UK) and Fumiaki Nakata (Subaru Telescope, National Astronomical Observatory of Japan). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the

  13. Full-kinetic elve model simulations and their comparison with the ISUAL observed events

    NASA Astrophysics Data System (ADS)

    Kuo, C.; Huang, T.; Chang, S.; Chou, J.; Lee, L.; Chen, A. B.; Su, H.; Hsu, R.; Frey, H. U.; Mende, S. B.; Takahashi, Y.; Lee, L.

    2011-12-01

    The duration of the optical emissions from elves is relatively short (<1 ms), and the intensity of the elve emissions is relatively weaker than that in the other types of TLEs (halos, sprites, blue jets and gigantic jets). Besides the major emission bands (N2-1P, N2-2P, and N2 LBH) [Mende et al., 2005; Kuo et al., 2007; Chang et al., 2010], other minor emissions in elves (e.g., N2+ 1N, O2 Atmoshperic band, O2+ 1N, OI 630 nm, OI 557.7 nm, NO-gamma band and OH* emission band [Huang et al., 2010]) have been explored using the ISUAL Imager equipped with specified filters (630/557.7/427.8-nm for example). We have also developed an electromagnetic finite difference time domain model for elves [Kuo et al., 2007] to investigate the full kinetic chemistry in elves [Sentman et al., 2008; Kuo et al., 2011]. The modeling results can provide the relatively intensity ratios of the major and the minor emissions in elves. The estimated relative intensities can be used to analyze for the involved radiative states and to infer their percentage that fall within the ISUAL Imager filter passing band. The simulation results could also be useful in designing the imager filters for the future TLE survey missions. [*Works were supported in part by the National Space Organization (NSPO) and the National Science Council (NSC) in Taiwan under grants NSC 99-2112-M-006-006-MY3, NSC 99-2111-M-006-001-MY3, NSC 100-2119-M-006-015

  14. Creative strategies of businesses with the holistic eigensolution in manufacturing industries

    NASA Astrophysics Data System (ADS)

    Zeichen, Gerfried; Huray, Paul G.

    1998-10-01

    It is a mission of this contribution to recognize and synthesize all the efforts in industry and in management science to strengthen our techniques and tools for successfully solving increasingly complex leadership problems in manufacturing industries. With the high standard of the work sharing method--the so called Taylorism principle--for cost efficient and mass production, invented at the beginning of the 20th century and the opening of the world market for global sales of goods and services a gigantic progress in living standards was reached. But at the beginning of the 21st century we are needing new ideas and methods for the guidance of overcoming increasing complexity. The holistic eigensolution presents a new operational framework for viewing and controlling the behavior of businesses. In contrast to the traditional process for viewing complex business systems through the intricate analysis of every part of that system, the authors have employed a technique used by physicists to understand the characteristic of `eigen' behaviors of complex physical systems. This method of systems analysis is achieved by observing interactions between the parts in a whole. This kind of analysis has a rigorous mathematical foundation in the physical world and it can be employed to understand most natural phenomena. Within a holistic framework, the observer is challenged to view the system form just the right perspective so that characteristic eigenmodes reveal themselves. The conclusion of the article describes why exactly the intelligent manufacturing science--especially in a broader sense--has the responsibility and chance to develop the holistic eigensolution framework as a Taylorism II-principle for the 21st century.

  15. Change in and Long-Term Investigation of Neuro-Otologic Disorders in Disaster-Stricken Fukushima Prefecture: Retrospective Cohort Study before and after the Great East Japan Earthquake

    PubMed Central

    Kuriyama, Shinichi; Obara, Taku; Hashimoto, Ken; Tateda, Yutaka; Okumura, Yuri; Kobayashi, Toshimitsu; Katori, Yukio

    2015-01-01

    On March 11, 2011, Japans northeast Pacific coast was hit by a gigantic earthquake and subsequent tsunami. Soma City in Fukushima Prefecture is situated approximately 44 km north of Fukushima Daiichi Nuclear Power Plant. Soma General Hospital is the only hospital in Soma City that provides full-time otolaryngological medical care. We investigated the changes in new patients from one year before to three years after the disaster. We investigated 18,167 new patients treated at our department during the four years from April 1, 2010 to March 31, 2014. Of the new patients, we categorized the diagnoses into Menieres disease, acute low-tone sensorineural hearing loss, vertigo, sudden deafness, tinnitus, and facial palsy as neuro-otologic symptoms. We also investigated the changes in the numbers of patients whom we examined at that time concerning other otolaryngological disorders, including epistaxis, infectious diseases of the laryngopharynx, and allergic rhinitis. The total number of new patients did not change remarkably on a year-to-year basis. Conversely, cases of vertigo, Menieres disease, and acute low-tone sensorineural hearing loss increased in number immediately after the disaster, reaching a plateau in the second year and slightly decreasing in the third year. Specifically, 4.8% of patients suffering from these neuro-otologic diseases had complications from depression and other mental diseases. With regard to new patients in our department, there was no apparent increase in the number of patients suffering from diseases other than neuro-otologic diseases, including epistaxis, and allergic rhinitis. Patients suffering from vertigo and/or dizziness increased during the first few years after the disaster. These results are attributed to the continuing stress and tension of the inhabitants. This investigation of those living in the disaster area highlights the need for long-term support. PMID:25849607

  16. Reproductive Biology and Its Impact on Body Size: Comparative Analysis of Mammalian, Avian and Dinosaurian Reproduction

    PubMed Central

    Werner, Jan; Griebeler, Eva Maria

    2011-01-01

    Janis and Carrano (1992) suggested that large dinosaurs might have faced a lower risk of extinction under ecological changes than similar-sized mammals because large dinosaurs had a higher potential reproductive output than similar-sized mammals (JC hypothesis). First, we tested the assumption underlying the JC hypothesis. We therefore analysed the potential reproductive output (reflected in clutch/litter size and annual offspring number) of extant terrestrial mammals and birds (as dinosaur analogs) and of extinct dinosaurs. With the exception of rodents, the differences in the reproductive output of similar-sized birds and mammals proposed by Janis and Carrano (1992) existed even at the level of single orders. Fossil dinosaur clutches were larger than litters of similar-sized mammals, and dinosaur clutch sizes were comparable to those of similar-sized birds. Because the extinction risk of extant species often correlates with a low reproductive output, the latter difference suggests a lower risk of population extinction in dinosaurs than in mammals. Second, we present a very simple, mathematical model that demonstrates the advantage of a high reproductive output underlying the JC hypothesis. It predicts that a species with a high reproductive output that usually faces very high juvenile mortalities will benefit more strongly in terms of population size from reduced juvenile mortalities (e.g., resulting from a stochastic reduction in population size) than a species with a low reproductive output that usually comprises low juvenile mortalities. Based on our results, we suggest that reproductive strategy could have contributed to the evolution of the exceptional gigantism seen in dinosaurs that does not exist in extant terrestrial mammals. Large dinosaurs, e.g., the sauropods, may have easily sustained populations of very large-bodied species over evolutionary time. PMID:22194835

  17. Contributions of Nimbus 7 TOMS Data to Volcanic Study and Hazard Mitigation

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin J.; Bluth, G. J. S.; Schaefer, S. A.

    1998-01-01

    Nimbus TOMS data have led to advancements among many volcano-related scientific disciplines, from the initial ability to quantify SO2 clouds leading to derivations of eruptive S budgets and fluxes, to tracking of individual clouds, assessing global volcanism and atmospheric impacts. Some of the major aspects of TOMS-related research, listed below, will be reviewed and updated: (1) Measurement of volcanic SO2 clouds: Nimbus TOMS observed over 100 individual SO2 clouds during its mission lifetime; large explosive eruptions are now routinely and reliably measured by satellite. (2) Eruption processes: quantification of SO2 emissions have allowed assessments of eruption sulfur budgets, the evaluation of "excess" sulfur, and inferences of H2S emissions. (3) Detection of ash: TOMS data are now used to detect volcanic particulates in the atmosphere, providing complementary analyses to infrared methods of detection. Paired TOMS and AVHRR studies have provided invaluable information on volcanic cloud compositions and processes. (4) Cloud tracking and hazard mitigation: volcanic clouds can be considered gigantic tracers in the atmosphere, and studies of the fates of these clouds have led to new knowledge of their physical and chemical dispersion in the atmosphere for predictive models. (5) Global trends: the long term data set has provided researchers an unparalleled record of explosive volcanism, and forms a key component in assessing annual to decadal trends in global S emissions. (6) Atmospheric impacts: TOMS data have been linked to independent records of atmospheric change, in order to compare cause and effect processes following a massive injection of SO2 into the atmosphere. (7) Future TOMS instruments and applications: Nimbus TOMS has given way to new satellite platforms, with several wavelength and resolution modifications. New efforts to launch a geostationary TOMS could provide unprecedented observations of volcanic activity.

  18. Magnetic Signatures of Impact Fractured Rocks from Sierra Madera, Texas, USA - Implications to Magnetic Anomalies on Mars

    NASA Astrophysics Data System (ADS)

    Adachi, T.; Kletetschka, G.; Wasilewski, P. J.; Mikula, V.

    2007-05-01

    Mars Express Orbiter (sounding radar data) revealed that craters of ancient origin had been covered by thick sediments in northern hemisphere. Mars MOLA topography mission identified many crater on Mars surface. Thus despite the Mars dichotomy, both northern and southern hemisphere have been covered by impacts to similar density. Mars currently has no global magnetic field of internal origin. In southern hemisphere, magnetic field intensities due to anomalies of remanent origin are much lower over the gigantic impact craters (e.g. Hellas, Prometheus, and Argyre). Low magnetic field may not relate to the absence of internal dynamo but due to impacts. For example, the aerial survey over a two billion year old, largest crater on Earth, Vredefort in South Africa observed much lower magnetic intensity over the crater, despite of the strongly magnetized simgle domain (SD) magnetite in shocked granites. Randomized magnetic vector orientations caused by impact may be the origin of the lower magnetic field observed on both Vredefort and Mars. We conducted magnetic analysis for a suite of Sierra Madera Impact deformed rock sites with complete shatter cone structures and multiple striated joint set (MSJS), and the initial results were intriguing. NRM vector orientations, REM ratios, and AF demagnetization curves showed contrasted magnetic signatures between the sites as well as within the samples. The NRM signatures in small scale shatter cones and larger scale shatter cones indicated shock demagnetization (SDM). The peculiar signatures of the site with MSJS may be both SDM and shock magnetization (SRM). We characterized the complexity and distinct magnetic signatures of impact fractured rocks. The results suggest that the size of the shatter cones and structures may reflect the magnetic signatures of both intensity and directions. Also, the dimensional scale of shatter cones is indicative parameters for randomization of the magnetic vector orientations. Such variations may influence on overall magnetic intensity observed from a distance, which relates to magnetic anomalies on Mars and Moons.

  19. Towards to Creation Unit Theory Oil Generation

    NASA Astrophysics Data System (ADS)

    Galant, Yuri

    2014-05-01

    Creating a unified theory of the genesis of oil encompasses all aspects of oil's life beginning from the formation the chemical elements. Globally, in the spatio-temporal aspect oil's life covers a Cosmic (pre geological) stage and geologically stage of formation of the planet Earth. In conces of spatio-temporal aspect unified theory of oil formation is based on the sequence of occurrences of chemical elements from which to create the Planet Earth and its Granite and Basalt Domains. From this standpoint is an independent Oil Domain along with Granite and Basalt. Sequence analysis of the appearance of chemical elements (H, C, N, O, Na, Mg, Al, Si, K, Ca, Ti, Fe, etc.) reveals the genesis of oil at a very early stage of the creation of Earth according appearance first of H and C. Next, according to the sequence of appearance (creation) of the elements are formed of Granite and Basalt Domain. The appearance of: (chemical element - serial number of) H 1, O 8 corresponds to the appearance of the aqueous layer. The appearance of Na 11, Al 13, Si 14 corresponds to the appearance of the Granite layer. The appearance of Ca 20, Fe 26 corresponds to the appearance of the Basalt layer. The process of formation of domains continues to today. Currently, Oil Domain encircles Globe on the south and north and manifests itself from micro quantities to gigantic clusters. In the formation of unit oil involves various methods involving initial elements C and H of various geneses. A unity of theory of oil generation in her polygenic !

  20. The Liang Bua faunal remains: a 95k.yr. sequence from Flores, East Indonesia.

    PubMed

    van den Bergh, G D; Meijer, H J M; Due Awe, Rokhus; Morwood, M J; Szab, K; van den Hoek Ostende, L W; Sutikna, T; Saptomo, E W; Piper, P J; Dobney, K M

    2009-11-01

    Excavations at Liang Bua, a limestone cave on the island of Flores, East Indonesia, have yielded a well-dated archaeological and faunal sequence spanning the last 95k.yr., major climatic fluctuations, and two human species -H. floresiensis from 95 to 17k.yr.(1), and modern humans from 11k.yr. to the present. The faunal assemblage comprises well-preserved mammal, bird, reptile and mollusc remains, including examples of island gigantism in small mammals and the dwarfing of large taxa. Together with evidence from Early-Middle Pleistocene sites in the Soa Basin, it confirms the long-term isolation, impoverishment, and phylogenetic continuity of the Flores faunal community. The accumulation of Stegodon and Komodo dragon remains at the site in the Pleistocene is attributed to Homo floresiensis, while predatory birds, including an extinct species of owl, were largely responsible for the accumulation of the small vertebrates. The disappearance from the sequence of the two large-bodied, endemic mammals, Stegodon florensis insularis and Homo floresiensis, was associated with a volcanic eruption at 17 ka and precedes the earliest evidence for modern humans, who initiated use of mollusc and shell working, and began to introduce a range of exotic animals to the island. Faunal introductions during the Holocene included the Sulawesi warty pig (Sus celebensis) at about 7ka, followed by the Eurasian pig (Sus scrofa), Long-tailed macaque, Javanese porcupine, and Masked palm civet at about 4ka, and cattle, deer, and horse - possibly by the Portuguese within historic times. The Holocene sequence at the site also documents local faunal extinctions - a result of accelerating human population growth, habitat loss, and over-exploitation. PMID:19058833

  1. The water balance components of undisturbed tropical woodlands in the Brazilian cerrado

    NASA Astrophysics Data System (ADS)

    Oliveira, P. T. S.; Wendland, E.; Nearing, M. A.; Scott, R. L.; Rosolem, R.; da Rocha, H. R.

    2015-06-01

    Deforestation of the Brazilian cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood but are important for making land management decisions in this region. To better understand pre-deforestation conditions, we determined the main components of the water balance for an undisturbed tropical woodland classified as "cerrado sensu stricto denso". We developed an empirical model to estimate actual evapotranspiration (ET) by using flux tower measurements and vegetation conditions inferred from the enhanced vegetation index and reference evapotranspiration. Canopy interception, throughfall, stemflow, surface runoff, and water table level were assessed from ground measurements. We used data from two cerrado sites, P de Gigante (PDG) and Instituto Arruda Botelho (IAB). Flux tower data from the PDG site collected from 2001 to 2003 were used to develop the empirical model to estimate ET. The other hydrological processes were measured at the field scale between 2011 and 2014 at the IAB site. The empirical model showed significant agreement (R2 = 0.73) with observed ET at the daily timescale. The average values of estimated ET at the IAB site ranged from 1.91 to 2.60 mm day-1 for the dry and wet seasons, respectively. Canopy interception ranged from 4 to 20 % and stemflow values were approximately 1 % of the gross precipitation. The average runoff coefficient was less than 1 %, while cerrado deforestation has the potential to increase that amount up to 20-fold. As relatively little excess water runs off (either by surface water or groundwater), the water storage may be estimated by the difference between precipitation and evapotranspiration. Our results provide benchmark values of water balance dynamics in the undisturbed cerrado that will be useful to evaluate past and future land-cover and land-use changes for this region.

  2. Testing for intraspecific postzygotic isolation between cryptic lineages of Pseudacris crucifer

    PubMed Central

    Stewart, Kathryn A; Lougheed, Stephen C

    2013-01-01

    Phenotypically cryptic lineages appear common in nature, yet little is known about the mechanisms that initiate and/or maintain barriers to gene flow, or how secondary contact between them might influence evolutionary trajectories. The consequences of such contact between diverging lineages depend on hybrid fitness, highlighting the potential for postzygotic isolating barriers to play a role in the origins of biological species. Previous research shows that two cryptic, deeply diverged intraspecific mitochondrial lineages of a North American chorus frog, the spring peeper (Pseudacris crucifer), meet in secondary contact in Southwestern Ontario, Canada. Our study quantified hatching success, tadpole survival, size at metamorphosis, and development time for experimentally generated pure lineage and hybrid tadpoles. Results suggest that lineages differ in tadpole survival and that F1 hybrids may have equal fitness and higher than average mass at metamorphosis compared with pure parental crosses. These findings imply hybrid early life viability may not be the pivotal reproductive isolation barrier helping to maintain lineage boundaries. However, we observed instances of tadpole gigantism, failure to metamorphose, and bent tails in some tadpoles from hybrid families. We also speculate and provide some evidence that apparent advantages or similarities of hybrids compared with pure lineage tadpoles may disappear when tadpoles are raised with competitors of different genetic makeup. This pilot study implies that ecological context and consideration of extrinsic factors may be a key to revealing mechanisms causing negative hybrid fitness during early life stages, a provocative avenue for future investigations on barriers to gene flow among these intraspecific lineages. PMID:24363891

  3. West-Antarctic Ice Streams: Analog to Ice Flow in Channels on Mars

    NASA Technical Reports Server (NTRS)

    Lucchitta, B. K.

    1997-01-01

    Sounding of the sea floor in front of the Ross Ice Shelf in Antarctica recently revealed large persistent patterns of longitudinal megaflutes and drumlinoid forms, which are interpreted to have formed at the base of ice streams during the list glacial advance. The flutes bear remarkable resemblance to longitudinal grooves and highly elongated streamlined islands found on the floors of some large martian channels, called outflow channels. ln addition, other similarities exist between Antarctic ice streams and outflow channels. Ice streams are 30 to 80 km wide and hundreds of kilometers long, as are the martian channels. Ice stream beds are below sea level. Floors of many martian outflow channels lie below martian datum, which may have been close to or below past martian sea levels. The Antarctic ice stream bed gradient is flat and locally may go uphill, and surface slopes are exceptionally low. So are gradients of martian channels. The depth to the bed in ice streams is 1 to 1.5 km. At bankful stage, the depth of the fluid in outflow channels would have been 1 to 2 km. These similarities suggest that the martian outflow channels, whose origin is commonly attributed to gigantic catastrophic floods, were locally filled by ice that left a conspicuous morphologic imprint. Unlike the West-Antarctic-ice streams, which discharge ice from an ice sheet, ice in the martian channels came from water erupting from the ground. In the cold martian environment, this water, if of moderate volume, would eventually freeze. Thus it may have formed icings on springs, ice dams and jams on constrictions in the channel path, or frozen pools. Given sufficient thickness and downhill surface gradient, these ice masses would have moved; and given the right conditions, they could have moved like Antarctic ice streams.

  4. Adaptive semi-supervised recursive tree partitioning: The ART towards large scale patient indexing in personalized healthcare.

    PubMed

    Wang, Fei

    2015-06-01

    With the rapid development of information technologies, tremendous amount of data became readily available in various application domains. This big data era presents challenges to many conventional data analytics research directions including data capture, storage, search, sharing, analysis, and visualization. It is no surprise to see that the success of next-generation healthcare systems heavily relies on the effective utilization of gigantic amounts of medical data. The ability of analyzing big data in modern healthcare systems plays a vital role in the improvement of the quality of care delivery. Specifically, patient similarity evaluation aims at estimating the clinical affinity and diagnostic proximity of patients. As one of the successful data driven techniques adopted in healthcare systems, patient similarity evaluation plays a fundamental role in many healthcare research areas such as prognosis, risk assessment, and comparative effectiveness analysis. However, existing algorithms for patient similarity evaluation are inefficient in handling massive patient data. In this paper, we propose an Adaptive Semi-Supervised Recursive Tree Partitioning (ART) framework for large scale patient indexing such that the patients with similar clinical or diagnostic patterns can be correctly and efficiently retrieved. The framework is designed for semi-supervised settings since it is crucial to leverage experts' supervision knowledge in medical scenario, which are fairly limited compared to the available data. Starting from the proposed ART framework, we will discuss several specific instantiations and validate them on both benchmark and real world healthcare data. Our results show that with the ART framework, the patients can be efficiently and effectively indexed in the sense that (1) similarity patients can be retrieved in a very short time; (2) the retrieval performance can beat the state-of-the art indexing methods. PMID:25656756

  5. Speciation on a conveyor belt: sequential colonization of the hawaiian islands by Orsonwelles spiders (Araneae, Linyphiidae).

    PubMed

    Hormiga, Gustavo; Arnedo, Miquel; Gillespie, Rosemary G

    2003-02-01

    Spiders of the recently described linyphiid genus Orsonwelles (Araneae, Linyphiidae) are one of the most conspicuous groups of terrestrial arthropods of Hawaiian native forests. There are 13 known Orsonwelles species, and all are single- island endemics. This radiation provides an excellent example of insular gigantism. We reconstructed the cladistic relationships of Orsonwelles species using a combination of morphological and molecular characters (both mitochondrial and nuclear sequences) within a parsimony framework. We explored and quantified the contribution of different character partitions and their sensitivity to changes in the traditional parameters (gap, transition, and transversion costs). The character data show a strong phylogenetic signal, robust to parameter changes. The monophyly of the genus Orsonwelles is strongly supported. The parsimony analysis of all character evidence combined recovered a clade with of all the non-Kauai Orsonwelles species; the species from Kauai form a paraphyletic assemblage with respect to the latter former clade. The biogeographic pattern of the Hawaiian Orsonwelles species is consistent with colonization by island progression, but alternative explanations for our data exist. Although the geographic origin of the radiation remains unknown, it appears that the ancestral colonizing species arrived first on Kauai (or an older island). The ambiguity in the area cladogram (i.e., post-Oahu colonization) is not derived from conflicting or unresolved phylogenetic signal among Orsonwelles species but rather from the number of taxa on the youngest islands. Speciation in Orsonwelles occurred more often within islands (8 of the 12 cladogenic events) than between islands. A molecular clock was rejected for the sequence data. Divergence times were estimated by using the nonparametric rate smoothing method of Sanderson (1997, Mol. Biol. Evol. 14:1218-1231) and the available geological data for calibration. The results suggest that the oldest divergences of Orsonwelles spiders (on Kauai) go back about 4 million years. PMID:12554442

  6. Origin of amphibian and avian chromosomes by fission, fusion, and retention of ancestral chromosomes

    PubMed Central

    Voss, Stephen R.; Kump, D. Kevin; Putta, Srikrishna; Pauly, Nathan; Reynolds, Anna; Henry, Rema J.; Basa, Saritha; Walker, John A.; Smith, Jeramiah J.

    2011-01-01

    Amphibian genomes differ greatly in DNA content and chromosome size, morphology, and number. Investigations of this diversity are needed to identify mechanisms that have shaped the evolution of vertebrate genomes. We used comparative mapping to investigate the organization of genes in the Mexican axolotl (Ambystoma mexicanum), a species that presents relatively few chromosomes (n = 14) and a gigantic genome (>20 pg/N). We show extensive conservation of synteny between Ambystoma, chicken, and human, and a positive correlation between the length of conserved segments and genome size. Ambystoma segments are estimated to be four to 51 times longer than homologous human and chicken segments. Strikingly, genes demarking the structures of 28 chicken chromosomes are ordered among linkage groups defining the Ambystoma genome, and we show that these same chromosomal segments are also conserved in a distantly related anuran amphibian (Xenopus tropicalis). Using linkage relationships from the amphibian maps, we predict that three chicken chromosomes originated by fusion, nine to 14 originated by fission, and 1217 evolved directly from ancestral tetrapod chromosomes. We further show that some ancestral segments were fused prior to the divergence of salamanders and anurans, while others fused independently and randomly as chromosome numbers were reduced in lineages leading to Ambystoma and Xenopus. The maintenance of gene order relationships between chromosomal segments that have greatly expanded and contracted in salamander and chicken genomes, respectively, suggests selection to maintain synteny relationships and/or extremely low rates of chromosomal rearrangement. Overall, the results demonstrate the value of data from diverse, amphibian genomes in studies of vertebrate genome evolution. PMID:21482624

  7. The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru.

    PubMed

    Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; de Muizon, Christian; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle

    2010-07-01

    The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths. Lacking a functional upper dentition, it relies on suction for catching its prey; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as raptorial (versus suction) feeders, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12-13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding. PMID:20596020

  8. Cometary Knots Around A Dying Star

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These gigantic, tadpole-shaped objects are probably the result of a dying star's last gasps. Dubbed 'cometary knots' because their glowing heads and gossamer tails resemble comets, the gaseous objects probably were formed during a star's final stages of life. Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas discovered thousands of these knots with the Hubble Space Telescope while exploring the Helix nebula, the closest planetary nebula to Earth at 450 light-years away in the constellation Aquarius. Although ground-based telescopes have revealed such objects, astronomers have never seen so many of them. The most visible knots all lie along the inner edge of the doomed star's ring, trillions of miles away from the star's nucleus. Although these gaseous knots appear small, they're actually huge. Each gaseous head is at least twice the size of our solar system; each tail stretches for 100 billion miles, about 1,000 times the distance between the Earth and the Sun. Astronomers theorize that the doomed star spews hot, lower-density gas from its surface, which collides with cooler, higher-density gas that had been ejected 10,000 years before. The crash fragments the smooth cloud surrounding the star into smaller, denser finger-like droplets, like dripping paint. This image was taken in August, 1994 with Hubble's Wide Field Planetary Camera 2. The red light depicts nitrogen emission ([NII] 6584A); green, hydrogen (H-alpha, 6563A); and blue, oxygen (5007A).

  9. Stretchy nerves are an essential component of the extreme feeding mechanism of rorqual whales.

    PubMed

    Vogl, A Wayne; Lillie, Margo A; Piscitelli, Marina A; Goldbogen, Jeremy A; Pyenson, Nicholas D; Shadwick, Robert E

    2015-05-01

    Rorqual whales (Balaenopteridae) are among the largest vertebrates that have ever lived and include blue (Balaenoptera musculus) and fin (Balaenoptera physalus) whales. Rorquals differ from other baleen whales (Mysticeti) in possessing longitudinal furrows or grooves in the ventral skin that extend from the mouth to the umbilicus. This ventral grooved blubber directly relates to their intermittent lunge feeding strategy, which is unique among vertebrates and was potentially an evolutionary innovation that led to gigantism in this lineage [1]. This strategy involves the rorqual whale rapidly engulfing a huge volume of prey-laden water and then concentrating the prey by more slowly expelling the water through baleen plates (Figure 1A). The volume of water engulfed during a lunge can exceed the volume of the whale itself [2]. During engulfment, the whale accelerates, opens its jaw until it is almost perpendicular to the rostrum, and then the highly compliant floor of the oral cavity is inflated by the incoming water [3]. The floor of the oral cavity expands by inversion of the tongue and ballooning of the adjacent floor of the mouth into the cavum ventrale, an immense fascial pocket between the body wall and overlying blubber layer that reaches as far back as the umbilicus. The ventral grooved blubber in fin whales expands by an estimated 162% in the circumferential direction and 38% longitudinally [4]. In fin whales, multiple lunges can occur during a single dive, and the average time between lunges is just over forty seconds [3]. Here, we show that nerves in the floor of the oral cavity of fin whales are highly extensible. PMID:25942546

  10. Ten-year transient luminous events and Earth observations of FORMOSAT-2

    NASA Astrophysics Data System (ADS)

    Chern, Rock Jeng-Shing; Lin, Shin-Fa; Wu, An-Ming

    2015-07-01

    The purpose of this paper is to summarize the enormous contributions of FS2 (FORMOSAT-2 or Formosa satellite #2) in both Earth and transient luminous events (TLEs) observations in 10 years. As a small satellite operated for 10 years (20 May 2004 to 20 May 2014) in orbit, FS2 keeps its two unique characteristics: (1) to orbit 14 revolutions around the Earth per day with daily revisit capability, and (2) to provide the capabilities of Earth observation in sunlight time and TLEs observation in eclipsed time every day. It carries two payloads: the remote sensing instrument (RSI) for Earth imaging in satellite's day time and the imager of sprites and upper atmospheric lightning instrument (ISUAL) for scientific observations in satellite's night time, respectively. Daily revisit capability provides changes of events on Earth in either short time (several days) or long term (several years). Examples include: Indian Ocean earthquake and tsunami (December 2004), disintegration of Wilkins Ice Shelf in Antarctica region (2006-2014, long term), Sichuan earthquake (May 2008), Tohoku earthquake and tsunami (March 2011), polar regions (2006-2014, long term), etc. In the TLEs observation, ISUAL had recorded more than 35,000 events in 10 years with 73.93% elves, 6.54% red sprites, 5.81% halos, 13.42% blue jets and 0.30% gigantic jets. Major contributions of FS2 in this specific scientific area are presented. In particular, current and future research topics on TLEs are discussed. Also, major contributions of FS2's RSI to the United Nations Institute for Training and Research (UNITAR) Operational Satellite Applications Programme (UNOSAT) and Group of Earth Observation System of Systems (GEOSS) are summarized. This paper also addresses briefly the health status of FS2 after working 10 years in orbit.

  11. First insights into the biodiversity and biogeography of the Southern Ocean deep sea.

    PubMed

    Brandt, Angelika; Gooday, Andrew J; Brando, Simone N; Brix, Saskia; Brkeland, Wiebke; Cedhagen, Tomas; Choudhury, Madhumita; Cornelius, Nils; Danis, Bruno; De Mesel, Ilse; Diaz, Robert J; Gillan, David C; Ebbe, Brigitte; Howe, John A; Janussen, Dorte; Kaiser, Stefanie; Linse, Katrin; Malyutina, Marina; Pawlowski, Jan; Raupach, Michael; Vanreusel, Ann

    2007-05-17

    Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748-6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment. PMID:17507981

  12. Chronological overlap between humans and megafauna in Sahul (Pleistocene Australia New Guinea): A review of the evidence

    NASA Astrophysics Data System (ADS)

    Field, Judith; Fillios, Melanie; Wroe, Stephen

    2008-08-01

    Over 60 faunal species disappeared from the Australian continent during the Middle-Late Pleistocene. Most of these animals were large to gigantic marsupials, birds and reptiles. A terminal extinction date of 46.4 kyr has been proposed for the megafauna, with all sites containing younger fossil megafauna dismissed by some researchers because of questions over stratigraphic integrity or chronologies. The timing of the extinctions is argued to be broadly coincident with estimates of first colonization of the continent by modern humans, and explanatory extinction models involving humans have subsequently gained currency. However there is considerable evidence to suggest that in some parts of the continent, people and some species of megafauna may have co-existed well beyond 46.4 kyr. In other places, such as Tasmania and the north of the continent, there is no known record of a human-megafauna temporal overlap. A review of the available evidence indicates that only 13 species of megafauna were extant on human arrival in Australia. The archaeology of this period indicates that rather than a focus on big game hunting or 'firestick farming', it was characterized by regional variability in subsistence strategies consistent with the range of environmental zones. At the present time there is no substantive argument for a terminal extinction date of 46.4 kyr, the current evidence indicating that there is no specific time period that correlates to any single mass extinction event. On the basis of available evidence arguments for either human or climatic causation are entirely circumstantial and implicitly require acceptance of many unproven assumptions. Claims to have eliminated climate as a primary driver are premature and the recent focus on delivering 'proof' of human causation in Pleistocene faunal extinctions diverts attention from achieving a better understanding of the differential impacts of climate change and short term climatic flux in a land of environmental extremes.

  13. Late Palaeozoic to Triassic evolution of the Turan and Scythian platforms: The pre-history of the Palaeo-Tethyan closure

    NASA Astrophysics Data System (ADS)

    Natal'in, Boris A.; ?engr, A. M. Cell

    2005-08-01

    A number of en chelon-arranged, southwest-facing arc fragments of Palaeozoic to Jurassic ages, sandwiched between two fairly straight east-northeast trending boundaries, constitute the basement of the Scythian and the Turan platforms located between the Laurasian and Tethyside units. They have until now largely escaped detection owing to extensive Jurassic and younger cover and the inaccessibility of the subsurface data to the international geological community. These units are separated from one another by linear/gently-curved faults of great length and steep dip. Those that are exposed show evidence of strike-slip motion. The arc units originally constituted parts of a single "Silk Road Arc" located somewhere south of the present-day central Asia for much of the Palaeozoic, although by the late Carboniferous they had been united into a continental margin arc south of the Tarim basin and equivalent units to the west and east. They were stacked into their present places in northern Afghanistan, Turkmenistan, Caucasus and the northern Black Sea by large-scale, right-lateral strike-slip coastwise transport along arc-slicing and arc-shaving strike-slip faults in the Triassic and medial Jurassic simultaneously with the subductive elimination of Palaeo-Tethys. This gigantic dextral zone ("the Silk Road transpression") was a trans-Eurasian structure and was active simultaneously with another, similar system, the Gornostaev keirogen and greatly distorted Eurasia. The late Palaeozoic to Jurassic internal deformation of the Dniepr-Donets aulacogen was also a part of the dextral strain in southern Europe. When the emplacement of the Scythian and Turan units was completed, the elimination of Palaeo-Tethys had also ended and Neo-Tethyan arcs were constructed atop their ruins, mostly across their southern parts. The western end of the great dextral zone that emplaced the Turan and Scythian units horsetails just east of north Dobrudja and a small component goes along the Tornquist-Teisseyre lineament.

  14. The REACH perspective: toward a new concept of toxicity testing.

    PubMed

    Schoeters, Greet

    2010-02-01

    A sustainable society and a healthy society are major goals for European policymakers. Although most Europeans live a longer healthy life than ever, there is growing concern and anxiety about unknown health risks and threats of chemicals and a strong demand for more knowledge and more control. European legislation is responding to these demands. An example is the program on Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), which came into force in 2007. It is a gigantic task for industry and for administrators to evaluate safety files of thousands of chemicals in a period of 12 years and to collect new data for chemicals not yet evaluated. Costs, number of toxicity tests, and number of animals that are needed are already well documented. REACH uses strict guidelines and focuses on apical endpoints that have been covered in the past by animal tests. Animal tests are slow, use unrealistic high doses, and have been shown to not always predict human toxicity correctly. The REACH program has made a clear opening for reduction of in vivo animal tests. Sharing toxicity data is a major improvement. For low tonnage levels, no further in vivo testing is allowed. The combination of scientifically valid information from alternative tests with available animal and human data into a weight-of-evidence approach is part of the integrated test strategy under REACH. Interpretation of this integrated information requires a high degree of expertise, flexibility, and openness toward scientific advances. This will be crucial for the success of the REACH program. It means a shift of attitude and will put a heavy responsibility on scientific experts and regulators, but it is also an opportunity for meeting the safety expectations of our modern society. PMID:20574899

  15. Convective storms in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Snchez-Lavega, A.

    2013-05-01

    The atmospheres of the planets in the Solar System have different physical properties that in some cases can be considered as extreme when compared with our own planet's more familiar atmosphere. From the tenuous and cold atmosphere of Mars to the dense and warm atmosphere of Venus in the case of the terrestrial planets, to the gigantic atmospheres of the outer planets, or the nitrogen and methane atmosphere of Saturn's moon Titan, we can find a large variety of physical environments. The comparative study of these atmospheres provides a better understanding of the physics of a geophysical fluid. In many of these worlds convective storms of different intensity appear. They are analogous to terrestrial atmospheres fed by the release of latent heat when one of the gases in the atmosphere condenses and they are therefore called moist convective storms. In many of these planets they can produce severe meteorological phenomena and by studying them in a comparative way we can aspire to get a further insight in the dynamics of these atmospheres even beyond the scope of moist convection. A classical example is the structure of the complex systems of winds in the giant planets Jupiter and Saturn. These winds are zonal and alternate in latitude but their deep structure is not accessible to direct observation. However the behaviour of large--scale convective storms vertically extending over the "weather layer" allows to study the buried roots of these winds. Another interesting atmosphere with a rather different structure of convection is Titan, a world where methane is close to its triple point in the atmosphere and can condense in bright clouds with large precipitation fluxes that may model part of the orography of the surface making Titan a world with a methane cycle similar to the hydrological cycle of Earth's atmosphere.

  16. Nuclear morphometry and proliferative activity evaluation in the gastrointestinal stromal tumors.

    PubMed

    Ardeleanu, Valeriu; Nechita, Aurel; Frncu, Laurian Lucian; Georgescu, Costinela

    2014-01-01

    Twenty-two cases with gastrointestinal stromal tumors (GISTs) have been studied, sized from 2 cm to invasive gigantic tumors and also from low to high degree of malignancy. The altering of the form and the size of the nucleus is a reference point of malignancy, being used in the histological grading of many types of tumors and also as an appreciating parameter of the tumoral prognosis, with a high degree of accuracy in the colorectal, uterine, prostatic or ovarian cancers, as it was pointed in the previous researches. The aim of this study is to evaluate the dimensional characteristic of the nuclei and the mitosis in GIST with a cholic and gastric localization, attempting a quantitative differentiation of the two tumors, by studying the following aspects: nuclear dimensions, mitotic activity index and the mitotic density. The results of the proliferative activity quantification (mitotic activity index and mitotic density) have shown that this can be a decisive criterion for the precocious appreciation of the evolution. The most important morphological criterion with a predictive role is the mitotic activity index, but is recommended to be applied correlated with the size and the localization of the tumor. Although various nuclear morphometry studies in different types of malignant tumors have been performed, the data in gastrointestinal stromal tumors is scarce and only few similar studies have been reported in the specialty literature; from this point of view, the present study is new and original and is also trying to point out that even with GIST, such analysis and prognosis is as valuable as in any other malignant diseases. PMID:24969981

  17. Inferences of Diplodocoid (Sauropoda: Dinosauria) Feeding Behavior from Snout Shape and Microwear Analyses

    PubMed Central

    Whitlock, John A.

    2011-01-01

    Background As gigantic herbivores, sauropod dinosaurs were among the most important members of Mesozoic communities. Understanding their ecology is fundamental to developing a complete picture of Jurassic and Cretaceous food webs. One group of sauropods in particular, Diplodocoidea, has long been a source of debate with regard to what and how they ate. Because of their long lineage duration (Late Jurassic-Late Cretaceous) and cosmopolitan distribution, diplodocoids formed important parts of multiple ecosystems. Additionally, fortuitous preservation of a large proportion of cranial elements makes them an ideal clade in which to examine feeding behavior. Methodology/Principal Findings Hypotheses of various browsing behaviors (selective and nonselective browsing at ground-height, mid-height, or in the upper canopy) were examined using snout shape (square vs. round) and dental microwear. The square snouts, large proportion of pits, and fine subparallel scratches in Apatosaurus, Diplodocus, Nigersaurus, and Rebbachisaurus suggest ground-height nonselective browsing; the narrow snouts of Dicraeosaurus, Suuwassea, and Tornieria and the coarse scratches and gouges on the teeth of Dicraeosaurus suggest mid-height selective browsing in those taxa. Comparison with outgroups (Camarasaurus and Brachiosaurus) reinforces the inferences of ground- and mid-height browsing and the existence of both non-selective and selective browsing behaviors in diplodocoids. Conclusions/Significance These results reaffirm previous work suggesting the presence of diverse feeding strategies in sauropods and provide solid evidence for two different feeding behaviors in Diplodocoidea. These feeding behaviors can subsequently be tied to paleoecology, such that non-selective, ground-height behaviors are restricted to open, savanna-type environments. Selective browsing behaviors are known from multiple sauropod clades and were practiced in multiple environments. PMID:21494685

  18. The 1994 EUROMET collection of micrometeorites at Cap-Prudhomme, Antarctica

    NASA Astrophysics Data System (ADS)

    Maurette, M.; Immel, G.; Engrand, C.; Kurat, G.; Pillinger, C. T.

    1994-07-01

    Advance funding from IFRTP (Institut Francais pour la Recherche et pour la Technique Polaire) for micrometeorite collection at Cap-Prudhomme has allowed construction of a new micrometeorite 'factory,' conceived to greatly reduce contamination of the ultraclean ice by our activities. The potential problems include fly ash, rust grains, fuel spills 'sticking to the shoes,' and trace elements from the plasticizers used in plastic tubing. In the new factory, intended to produce and then cycle 10-15 tons of melt ice water per day, all parts exposed to water were replaced by either stainless steel or teflon. After examination with a microscope and their transfer into teflon and or glass vials, all samples were frozen the day of their collection. The factory operated from December 15, 1993, through February 6, 1994. Problems included injuries as well as very bad weather conditions, characterized by both the heaviest snow falls observed and unexpected gusts from a blizzard. Also, several new components of the factory did not function properly under the extreme conditions of Antarctica. Our major objective was to obtain the 'cleanest' and 'purest' 25-50 microns micrometeorites ever collected in Antarctica, for comparison with stratospheric Interplanetary Dust Particles (IDPs). We could not fulfill this premise, but we recovered the best 100-400-micron-size fraction of 'giant' micrometeorites ever collected on Earth. Our 26 daily collections are listed,refering to an 'index of quality.' Aliquots of these daily collections will be distributed to major institutions in Austria, England, the U.S.A., and Japan, to be preserved for future generations. The Antarctica ice sheet is truly a gigantic, ultraclean, and inexhaustible micrometeorite collector, but it is very tricky to recover 'ultraclean' micrometeorites from it.

  19. Comparative Transcriptome Profiling of the Early Response to Magnaporthe oryzae in Durable Resistant vs Susceptible Rice (Oryza sativa L.) Genotypes

    PubMed Central

    Bagnaresi, Paolo; Biselli, Chiara; Orr, Luigi; Urso, Simona; Crispino, Laura; Abbruscato, Pamela; Piffanelli, Pietro; Lupotto, Elisabetta; Cattivelli, Luigi; Val, Giampiero

    2012-01-01

    Durable resistance to blast, the most significant fungal disease of rice, represents an agronomically relevant character. Gigante Vercelli (GV) and Vialone Nano (VN) are two old temperate japonica Italian rice cultivars with contrasting response to blast infection: GV displays durable and broad resistance while VN is highly susceptible. RNA-seq was used to dissect the early molecular processes deployed during the resistance response of GV at 24 h after blast inoculation. Differential gene expression analysis identified 1,070 and 1,484 modulated genes, of which 726 and 699 were up regulated in response to infection in GV and VN, respectively. Gene ontology (GO) enrichment analyses revealed a set of GO terms enriched in both varieties but, despite this commonality, the gene sets contributing to common GO enriched terms were dissimilar. The expression patterns of genes grouped in GV-specific enriched GO terms were examined in detail including at the transcript isoform level. GV exhibited a dramatic up-regulation of genes encoding diterpene phytoalexin biosynthetic enzymes, flavin-containing monooxygenase, class I chitinase and glycosyl hydrolase 17. The sensitivity and high dynamic range of RNA-seq allowed the identification of genes critically involved in conferring GV resistance during the early steps of defence perception-signalling. These included chitin oligosaccharides sensing factors, wall associated kinases, MAPK cascades and WRKY transcription factors. Candidate genes with expression patterns consistent with a potential role as GV-specific functional resistance (R) gene(s) were also identified. This first application of RNA-seq to dissect durable blast resistance supports a crucial role of the prompt induction of a battery of responses including defence-related genes as well as members of gene families involved in signalling and pathogen-related gene expression regulation. PMID:23251593

  20. Imaging sprites aboard TARANIS

    NASA Astrophysics Data System (ADS)

    Farges, Thomas; Blanc, Elisabeth; Sato, Mitsuteru; Takahashi, Yukihiro; Suzuki, Makoto; Grosjean, Olivier

    TLE (Transient Luminous Event) is the generic name for phenomena which occur over thundercloud from the troposphere to the lower thermosphere (20 to 100 km-height). They are called sprites, elves, blue jets, gigantic jets . . . Each class of phenomenon has their own properties: duration, vertical and horizontal extension, delay after their parent lightning. They are mainly observed from ground since 1990 and from space since 2004 with the ISUAL experiment. All these observations have been done pointing at the limb. We propose an experiment, to image and characterize TLEs and lightning from space, which novelty is looking at the nadir. This concept was tested by the CEA with the Lightning and Sprite Observations on board the International Space Station from 2001 to 2004. The advantage of this point of view is that other radiations (as gamma-rays, electron beams, or electrostatic field) emitted mainly vertically and simultaneously to TLE or lightning can be observed with the same satellite, but the difficulty is how the superimposed light from lightning and TLE can be differentiate. Taking account this constraint and other ones due to satellite accommodation, we define a set of sensors allowing the detection, the localisation and the characterisation of lightning and TLE. Our studies show that two cameras and four photometers are necessary to reach those objectives. This experiment, called MCP for MicroCameras and Photometers, will be aboard TARANIS (Tool for the Analysis of RAdiations from lightNIngs and Sprites) which is a microsatellite project of the CNES Myriade program with a launch planned in 2011. The photometer set will be provided by a Japanese team joining Hokkaido and Tohoku Universities and ISAS/JAXA. In this talk, we will present the main scientific goals of MCP. Need requirement studies (particularly radiometric analysis including sensor trade-off) will be described. We will finish describing the actual development status of the sensors.

  1. Analysis of telescope array receivers for deep-space inter-planetary optical communication link between Earth and Mars

    NASA Astrophysics Data System (ADS)

    Hashmi, Ali Javed; Eftekhar, Ali Asghar; Adibi, Ali; Amoozegar, Farid

    2010-05-01

    Optical communication technology shows promising prospects to fulfill the large bandwidth communication requirements of future deep-space exploration missions that are launched by NASA and various other international space agencies. At Earth, a telescope with a large aperture diameter is required to capture very weak optical signals that are transmitted from distant planets and to support large bandwidth communication link. A single large telescope has the limitations of cost, single point failure in case of malfunction, difficulty in manufacturing high quality optics, maintenance, and trouble in providing communication operations when transmitting spacecraft is close to the Sun. An array of relatively smaller-sized telescopes electrically connected to form an aggregate aperture area equivalent to a single large telescope is a viable alternative to a monolithic gigantic aperture. In this paper, we present the design concept and analysis of telescope array receivers for an optical communication link between Earth and Mars. Pulse-position modulation (PPM) is used at the transmitter end and photon-counting detectors along with the direct-detection technique are employed at each telescope element in the array. We also present the optimization of various system parameters, such as detector size (i.e., receiver field of view), PPM slot width, and the PPM order M, to mitigate the atmospheric turbulence and background noise effects, and to maximize the communication system performance. The performance of different array architectures is evaluated through analytical techniques and Monte-Carlo simulations for a broad range of operational scenarios, such as, Earth-Mars conjunction, Earth-Mars opposition, and different background and turbulence conditions. It is shown that the performance of the telescope array-based receiver is equivalent to a single large telescope; and as compared to current RF technology, telescope array-based optical receivers can provide several orders of magnitude greater data rates for deep-space communication with Mars.

  2. Extreme plasticity in life-history strategy allows a migratory predator (jumbo squid) to cope with a changing climate.

    PubMed

    Hoving, Henk-Jan T; Gilly, William F; Markaida, Unai; Benoit-Bird, Kelly J; -Brown, Zachary W; Daniel, Patrick; Field, John C; Parassenti, Liz; Liu, Bilin; Campos, Bernardita

    2013-07-01

    Dosidicus gigas (jumbo or Humboldt squid) is a semelparous, major predator of the eastern Pacific that is ecologically and commercially important. In the Gulf of California, these animals mature at large size (>55cm mantle length) in 1-1.5years and have supported a major commercial fishery in the Guaymas Basin during the last 20years. An El Nio event in 2009-2010, was accompanied by a collapse of this fishery, and squid in the region showed major changes in the distribution and life-history strategy. Large squid abandoned seasonal coastal-shelf habitats in 2010 and instead were found in the Salsipuedes Basin to the north, an area buffered from the effects of El Nio by tidal upwelling and a well-mixed water column. The commercial fishery also relocated to this region. Although large squid were not found in the Guaymas Basin from 2010 to 2012, small squid were abundant and matured at an unusually small mantle-length (<30cm) and young age (approximately 6months). Juvenile squid thus appeared to respond to El Nio with an alternative life-history trajectory in which gigantism and high fecundity in normally productive coastal-shelf habitats were traded for accelerated reproduction at small size in an offshore environment. Both small and large mature squid, were present in the Salsipuedes Basin during 2011, indicating that both life- history strategies can coexist. Hydro-acoustic data, reveal that squid biomass in this study area nearly doubled between 2010 and 2011, primarily due to a large increase in small squid that were not susceptible to the fishery. Such a climate-driven switch in size-at-maturity may allow D. gigas to rapidly adapt to and cope with El Nio. This ability is likely to be an important factor in conjunction with longerterm climate-change and the potential ecological impacts of this invasive predator on marine ecosystems. PMID:23505049

  3. Histological analysis of aggressiveness and responsiveness in Wilms' tumor.

    PubMed

    Beckwith, J B; Zuppan, C E; Browning, N G; Moksness, J; Breslow, N E

    1996-11-01

    The clinical behavior and outcome for any neoplasm are determined originally by its aggressiveness. As adjuvant therapy becomes increasingly effective for that neoplasm, responsiveness to therapy assumes a larger role in determining outcome. Wilms' tumor (WT) provides instructive examples of the dissociation of aggressiveness from responsiveness. The presence of gigantic nuclei with multipolar mitotic figures (anaplasia) appears to be a marker of resistance to therapy, but not of increased aggressiveness. For this reason, anaplasia in a stage 1 WT and anaplasia confined to discrete foci within the primary tumor have no adverse prognostic significance following surgical resection. The prognostic significance of anaplasia is apparently limited to those patients in whom anaplastic cells remain following attempted surgical resection. WT with predominantly epithelial differentiation usually have a low degree of aggressiveness. In this study, 81.3% of WT with this pattern were stage 1. This feature accounts for the high cure rate associated with this pattern prior to the advent of effective adjuvant therapy. However, epithelial predominant WT that present with advanced stage disease may be quite resistant to therapy, with relapse and death rates higher than for more aggressive WT patterns. In contrast, the diffuse blastemal pattern is associated with marked aggressiveness, but with high survival rates suggesting it is usually responsive to current therapy. These features illustrate the independence of aggressiveness and responsiveness in determining outcome for some patients with cancer. Grading systems must be reevaluated with each significant change in therapy. In order to formulate rational therapy, it is important to determine whether prognostic markers are associated with aggressiveness or responsiveness. PMID:8827069

  4. Male meiosis, morphometric analysis and distribution pattern of 2 and 4 cytotypes of Ranunculus hirtellus Royle, 1834 (Ranunculaceae) from the cold regions of northwest Himalayas (India).

    PubMed

    Kumar, Puneet; Singhal, Vijay Kumar

    2011-01-01

    In this study, we examined the chromosome number, detailed male meiosis, microsporogenesis, pollen fertility and morphological features and distribution of 2 and 4 cytotypes of Ranunculus hirtellus Royle, 1834. The majority of the populations scored now from cold regions of the northwest Himalayas showed tetraploid (n=16) meiotic chromosome count and one of the populations studied from the Manimahesh hills existed at diploid level (n=8). The individuals of diploid cytotype exhibited perfectly normal meiotic course resulting in 100% pollen fertility and pollen grains of uniform sizes. On the other hand, the plants of the tetraploid cytotype from all the populations in spite of showing normal bivalent formation and equal distribution to the opposite poles at anaphases showed various meiotic abnormalities. The most prominent among these meiotic abnormalities was the cytomixis which involved inter PMC (pollen mother cell) chromatin material transfer at different stages of meiosis-I. The phenomenon of cytomixis induced various meiotic abnormalities which include chromatin stickiness, pycnotic chromatin, laggards and chromatin bridges, out of plate bivalents at metaphase-I, disoriented chromatin material at anaphase/telophase and micronuclei. Consequently, these populations exhibited varying percentages of pollen sterility (24 - 77 %) and pollen grains of heterogeneous sizes. Analysis of various morphometric features including the stomata in 2 and 4 cytotypes showed that increase in ploidy level in the species is correlated with gigantism of vegetative and floral characters and the two cytotypes can be distinguished from each other on the basis of morphological characters. The distribution patterns of the 2 and 4 cytotypes now detected and 2, 3, 4 cytotypes detected earlier by workers from other regions of the Indian Himalayas have also been discussed. PMID:24260626

  5. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Haser, Fritz; Starr, David (Technical Monitor)

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the 2002 Winter Olympic Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes and "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science and on National and International Network TV. New computer software tools allow us to roam and zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds. data. Spectacular new visualizations of the global atmosphere and oceans are shown. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  6. Visions of Our Planet's Atmosphere, Land and Oceans Electronic-Theater 2001

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The NASA/NOAA/AMS Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Fredericton New Brunswick. Drop in on the Kennedy Space Center and Park City Utah, site of the 2002 Olympics using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and International global satellite weather movies including hurricanes & tornadoes. See the latest spectacular images from NASA/NOAA and Canadian remote sensing missions like Terra GOES, TRMM, SeaWiFS, Landsat 7, and Radarsat that are visualized & explained. See how High Definition Television (HDTV) is revolutionizing the way we communicate science in cooperation with the American Museum of Natural History in NYC. See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on Newsweek, TIME, National Geographic, Popular Science covers & National & International Network TV. New visualization tools allow us to roam & zoom through massive global images eg Landsat tours of the US, Africa, & New Zealand showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny plankton and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. The demonstration is interactively driven by a SGI Onyx II Graphics Supercomputer with four CPUs, 8 Gigabytes of RAM and Terabyte of disk. With multiple projectors on a giant screen. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  7. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic-Theater 2002. Spectacular Visualizations of our Blue Marble

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2002-01-01

    Spectacular Visualizations of our Blue Marble The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the 2002 Winter Olympic Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC). See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vertexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nicola Nina climate changes. See the city lights, fishing fleets, gas flares and biomass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  8. RING E3 mechanism for ubiquitin ligation to a disordered substrate visualized for human anaphase-promoting complex.

    PubMed

    Brown, Nicholas G; VanderLinden, Ryan; Watson, Edmond R; Qiao, Renping; Grace, Christy R R; Yamaguchi, Masaya; Weissmann, Florian; Frye, Jeremiah J; Dube, Prakash; Ei Cho, Shein; Actis, Marcelo L; Rodrigues, Patrick; Fujii, Naoaki; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

    2015-04-28

    For many E3 ligases, a mobile RING (Really Interesting New Gene) domain stimulates ubiquitin (Ub) transfer from a thioester-linked E2?Ub intermediate to a lysine on a remotely bound disordered substrate. One such E3 is the gigantic, multisubunit 1.2-MDa anaphase-promoting complex/cyclosome (APC), which controls cell division by ubiquitinating cell cycle regulators to drive their timely degradation. Intrinsically disordered substrates are typically recruited via their KEN-box, D-box, and/or other motifs binding to APC and a coactivator such as CDH1. On the opposite side of the APC, the dynamic catalytic core contains the cullin-like subunit APC2 and its RING partner APC11, which collaborates with the E2 UBCH10 (UBE2C) to ubiquitinate substrates. However, how dynamic RING-E2?Ub catalytic modules such as APC11-UBCH10?Ub collide with distally tethered disordered substrates remains poorly understood. We report structural mechanisms of UBCH10 recruitment to APC(CDH1) and substrate ubiquitination. Unexpectedly, in addition to binding APC11's RING, UBCH10 is corecruited via interactions with APC2, which we visualized in a trapped complex representing an APC(CDH1)-UBCH10?Ub-substrate intermediate by cryo-electron microscopy, and in isolation by X-ray crystallography. To our knowledge, this is the first structural view of APC, or any cullin-RING E3, with E2 and substrate juxtaposed, and it reveals how tripartite cullin-RING-E2 interactions establish APC's specificity for UBCH10 and harness a flexible catalytic module to drive ubiquitination of lysines within an accessible zone. We propose that multisite interactions reduce the degrees of freedom available to dynamic RING E3-E2?Ub catalytic modules, condense the search radius for target lysines, increase the chance of active-site collision with conformationally fluctuating substrates, and enable regulation. PMID:25825779

  9. Nitrogen in Solar System Minor Bodies: Delivery Pathways to Primeval Earth

    NASA Astrophysics Data System (ADS)

    Trigo-Rodrguez, Josep M.

    Oxygen isotope data point towards enstatite and ordinary chondrites as presumable building blocks of primordial Earth. Nitrogen was incorporated as nitrides to these first building blocks and was outgassed in the early stages of chemical segregation. However, giant impacts with planetesimals played an important role in partially eroding the atmosphere of Earth, and promoting thermal escape of diverse components. As a consequence, the Earth's atmospheric composition could have been subjected to important changes along the eons. A last, and probably less massive, delivery of volatiles took place at the time of a gigantic cataclysm known as Late Heavy Bombardment. During a short interval roughly between 3.9 and 3.8 Gyr ago, a gravitational migration inwards of Jupiter and Saturn occurred, that perturbed hundreds of small bodies rich in water, ammonia, methane and organic compounds that were stored until then in the outer regions. Current atmospheric signatures suggest that by that mechanism a continuous shower of outer-disk primordial components enriched the volatile inventory of terrestrial planets. The relevance of such contribution is still debated, but significant progress has been made in the last decades from the study of undifferentiated bodies. Consequently, planetary scattering of undifferentiated bodies delivered to Earth a significant fraction of minerals, and light elements that could have played a key role in the volatile enrichment the terrestrial crust. I suggest some unexplored pathways to allow a safe delivery of organics to Earth's surface, following recent evidence on meteoroid fragmentation, fireball spectra and Antarctic micrometeorite discoveries. Recent compositional studies of asteroids, comets and meteorites corroborate the need of having more precise data on the abundance and isotopic ratios of N in these minor bodies. Future space missions to primitive bodies like Rosetta, OSIRIS-Rex, Hayabusa II, or Marco Polo-R could help us to complete the big picture, and this chapter tries to compile our present knowledge of its delivery to Earth along the eons.

  10. Organization of the nervous system in the pygmy cuttlefish, Idiosepius paradoxus ortmann (Idiosepiidae, Cephalopoda).

    PubMed

    Shigeno, Shuichi; Yamamoto, Masamichi

    2002-10-01

    The idiosepiid cuttlefish is a suitable organism for behavioral, genetic, and developmental studies. As morphological bases for these studies, organization of the nervous system was examined in Idiosepius paradoxus Ortmann, 1881, using Cajal's silver technique and immunohistochemical staining with anti-acetylated alpha-tubulin antibody. The nervous architecture is generally identical to that described in Sepia and Loligo, but some features characterize the idiosepiid nervous system. The olfactory system is highly developed in the optic tract region. The dorsolateral lobes show large neuropils, connected with each other by a novel well-fasciculated commissure. Each olfactory lobe is subdivided into two lobules. The neuropils of the anterior and the posterior chromatophore lobes are very poorly developed. Neuronal gigantism is not extensive in the brain; enlarged neuronal cells are visible only in the perikaryal layer of the posterior subesophageal mass. The giant nerve fiber system is of the Sepia type; the axons are not markedly thick and the first-order giant fibers do not fuse with each other at the chiasma. Three-dimensional images by whole-mount immunostaining clarified the innervation pattern in the peripheral nervous system in detail. Two commissural fibers link the left and right posterior funnel nerves ventrally and dorsally. The stellate commissure, which is absent in Sepia and Sepiola, connects the stellate ganglia with each other. A branch of the visceral nerve innervating the median pallial adductor muscle is characteristically thick. Tubulinergic reactivity of the cilia and axons reveals the presence of many ciliated cells giving off an axon toward brain nerves in the surface of the funnel, head integument, arm tips, and epidermal lines. Some of these features seem to reflect the inactive nekto-benthic life of the idiosepiid cuttlefish in the eelgrass bed. PMID:12219344

  11. The evolution of high energy accelerators

    SciTech Connect

    Courant, E.D.

    1994-08-01

    Accelerators have been devised and built for two reasons: In the first place, by physicists who needed high energy particles in order to have a means to explore the interactions between particles that probe the fundamental elementary forces of nature. And conversely, sometimes accelerator builders produce new machines for higher energy than ever before just because it can be done, and then challenge potential users to make new discoveries with the new means at hand. These two approaches or motivations have gone hand in hand. This lecture traces how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to the gigantic projects of today. So far all the really high-energy machines built and planned in the world--except the SLC--have been ring accelerators and storage rings using the strong-focusing method. But this method has not removed the energy limit, it has only pushed it higher. It would seem unlikely that one can go beyond the Large Hadron Collider (LHC)--but in fact a workshop was held in Sicily in November 1991, concerned with the question of extrapolating to 100 TeV. Other acceleration and beam-forming methods are now being discussed--collective fields, laser acceleration, wake-field accelerators etc., all aimed primarily at making linear colliders possible and more attractive than with present radiofrequency methods. So far it is not entirely clear which of these schemes will dominate particle physics in the future--maybe something that has not been thought of as yet.

  12. Earth after the Moon-forming Impact

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.

    2006-01-01

    The Hadean Earth is widely and enduringly pictured as a world of exuberant volcanism, exploding meteors, huge craters, infernal heat, and billowing sulfurous steams; i.e., a world of fire and brimstone punctuated with blows to the head. In the background the Moon looms gigantic in the sky. The popular image has given it a name that celebrates our mythic roots. A hot early Earth is an inevitable consequence of accretion. The Moon-forming impact ensured that Earth as we know it emerged from a fog of silicate vapor. The impact separated the volatiles from the silicates. It took approx. 100 years to condense and rain out the bulk of the vaporized silicates, although relatively volatile elements may have remained present in the atmosphere throughout the magma ocena stage. The magma ocean lasted approx. 2 Myr, its lifetime prolonged by tidal heating and thermal blanketing by a thick CO2-rich steam atmosphere. Water oceans condensed quickly after the mantle solidified, but for some 10-100 Myr the surface would have stayed warm (approx. 500 K) until the CO2 was removed into the mantle. Thereafter the faint young Sun suggests that a lifeless Earth would always have been evolving toward a bitterly cold ice world, but the cooling trend was fiequently interrupted by volcanic or impact induced thaws. A cartoon history of water, temperature, and carbon dioxide in the aftermath of the moon-formining-impact is shown. How long it stays hot depends on how long it takes to scrub the C02 out of the atmosphere.

  13. August 2014 Hiroshima landslide disaster and its societal impact

    NASA Astrophysics Data System (ADS)

    Fukuoka, Hiroshi; Sassa, Kyoji; Wang, Chunxiang

    2015-04-01

    In the early morning of August 20, 2014, Hiroshima city was hit by a number of debris flows along a linear rain band which caused extreme downpour. This disaster claimed 74 death, although this city experienced very similar disaster in 1999, claiming more than 30 residents lives. In the most severely affected debris flow torrent, more than 50 residents were killed. Most of the casualties arose in the wooden, vulnerable houses constructed in front of the exit of torrents. Points and lessons learnt from the disaster are as follows: 1. Extreme rainfall events : geology and geomorphology does not much affect the distribution of landslides initiation sites. 2. Area of causative extreme rainfall is localized in 2 km x 10 km along the rain band. 3. Authors collected two types of sands from the source scar of the initial debris slides which induced debris flows. Tested by the ring shear apparatus under pore-pressure control condition, clear "Sliding surface liquefaction" was confirmed for both samples even under small normal stress, representing the small thickness of the slides. These results shows even instant excess pore pressure could initiate the slides and trigger slide-induced debris flow by undrained loading onto the torrent deposits. 4. Apparently long-term land-use change affected the vulnerability of the community. Residential area had expanded into hill-slope (mountainous / semi-mountainous area) especially along the torrents. Those communities were developed on the past debris flow fan. 5. As the devastated area is very close to downtown of Hiroshima city, it gave gigantic societal impact to the Japanese citizens. After 1999 Hiroshima debris flow disaster, the Landslide disaster reduction law which intends to promote designation of landslide potential risk zones, was adopted in 2000. Immediately after 2014 disaster, national diet approved revision of the bill.

  14. Prevalence and Risk Factors for Depressive Reaction among Resident Survivors after the Tsunami following the Great East Japan Earthquake, March 11, 2011

    PubMed Central

    Matsubara, Chieko; Murakami, Hitoshi; Imai, Koubun; Mizoue, Tetsuya; Akashi, Hidechika; Miyoshi, Chiaki; Nakasa, Tamotsu

    2014-01-01

    Objectives The Great East Japan Earthquake caused a gigantic tsunami which devastated coastal areas of northern Japan on 11 March 2011. Despite the large number of resident survivors who continued to reside in their damaged houses on the second or upper floors, research on the mental health of these individuals has been limited. This study explored the prevalence of depressive reaction and risk factors for depressive reaction among these resident survivors. Methods A cross-sectional household health support needs screening was conducted for resident survivors in Higashi-Matsushima city, Miyagi prefecture, two to four months after the tsunami. The health interview that was conducted including mental status, assessed by the Patient Health Questionnaire-2 (PHQ-2). Results Of 5,454 respondents, 8.1% had depressive reaction. After adjustment by the number of weeks from the tsunami and the mortality rate at each respondent's place of residence, depressive reaction was significantly associated with house flooding below or above the ground floor (odds ratios of 1.92, 2.36, respectively), the unavailability of gas supply (odds ratio, 1.67), being female (odds ratio, 1.47), middle aged or elderly (odds ratios of 2.41, 2.42, respectively), regular intake of psychotropic medicine(s) since before the tsunami (odds ratio, 2.53) and the presence of one to five or more than six cohabiters (odds ratios of 0.61, 0.52, respectively). Conclusions The results suggest a considerable psychological burden (depressive reaction) following the tsunami among resident survivors. Special supports for families with psychiatric problems need to be considered among resident survivors. Restoration of lifeline utilities and the strengthening of social ties of persons living alone may help prevent depressive reaction among resident survivors after a tsunami. PMID:25279563

  15. Thermal and electrical conductivity of iron at Earth's core conditions.

    PubMed

    Pozzo, Monica; Davies, Chris; Gubbins, David; Alf, Dario

    2012-05-17

    The Earth acts as a gigantic heat engine driven by the decay of radiogenic isotopes and slow cooling, which gives rise to plate tectonics, volcanoes and mountain building. Another key product is the geomagnetic field, generated in the liquid iron core by a dynamo running on heat released by cooling and freezing (as the solid inner core grows), and on chemical convection (due to light elements expelled from the liquid on freezing). The power supplied to the geodynamo, measured by the heat flux across the core-mantle boundary (CMB), places constraints on Earth's evolution. Estimates of CMB heat flux depend on properties of iron mixtures under the extreme pressure and temperature conditions in the core, most critically on the thermal and electrical conductivities. These quantities remain poorly known because of inherent experimental and theoretical difficulties. Here we use density functional theory to compute these conductivities in liquid iron mixtures at core conditions from first principles--unlike previous estimates, which relied on extrapolations. The mixtures of iron, oxygen, sulphur and silicon are taken from earlier work and fit the seismologically determined core density and inner-core boundary density jump. We find both conductivities to be two to three times higher than estimates in current use. The changes are so large that core thermal histories and power requirements need to be reassessed. New estimates indicate that the adiabatic heat flux is 15 to 16 terawatts at the CMB, higher than present estimates of CMB heat flux based on mantle convection; the top of the core must be thermally stratified and any convection in the upper core must be driven by chemical convection against the adverse thermal buoyancy or lateral variations in CMB heat flow. Power for the geodynamo is greatly restricted, and future models of mantle evolution will need to incorporate a high CMB heat flux and explain the recent formation of the inner core. PMID:22495307

  16. Building baluchitherium and indricotherium: imperial and international networks in early-twentieth century paleontology.

    PubMed

    Manias, Chris

    2015-05-01

    Over the first decades of the twentieth century, the fragmentary remains of a huge prehistoric ungulate were unearthed in scientific expeditions in India, Turkestan and Mongolia. Following channels of formal and informal empire, these were transported to collections in Britain, Russia and the United States. While striking and of immense size, the bones proved extremely difficult to interpret. Alternately naming the creature Paraceratherium, Baluchitherium and Indricotherium, paleontologists Clive Forster-Cooper, Alexei Borissiak and Henry Fairfield Osborn struggled over the reconstruction of this gigantic fossil mammal. However, despite these problems, shared work on the creature served as a focus for collaboration and exchange rather than rivalry between these three scientific communities. Not only did the initial interpretation and analysis depend on pre-existing connections between British and American paleontological institutions, but the need for comparative material, recognition and contacts brought British and American scholars into communication and exchange with their counterparts in the Soviet Union. This article examines these processes. It first uses these excavations as a comparative case-study of different manifestations of colonial science in this period, examining how scholars in the Britain, the Russian Empire and the United States used formal and informal colonial links to Asia to pursue new research. It then moves to examine how the common problem of reconstructing this giant animal drew metropolitan scientific communities together, at least for a time. The construction of the Baluchitherium and Indricotherium illustrates the drives to expand research both imperially and internationally in the early-twentieth century, but also the continual problems in resources, institutionalization, transport and communication that could run up against scientific work. PMID:25537636

  17. New insights into regional tectonics of the Indochina Peninsula inferred from Lower-Middle Jurassic paleomagnetic data of the Sibumasu Terrane

    NASA Astrophysics Data System (ADS)

    Fujiwara, Katsuya P.; Zaman, Haider; Surinkum, Adichat; Chaiwong, Nikhom; Fujihara, Makoto; Ahn, Hyeon-Seon; Otofuji, Yo-ichiro

    2014-11-01

    The post-Jurassic occurrence of differential tectonic rotation between the Indochina and South Sundaland blocks remains an issue to be properly investigated. New paleomagnetic study is used here to find the role of Sibumasu Terrane in this rotation, which is located between a clockwise rotated Indochina Block and a counter-clockwise rotated South Sundaland Block. For this purpose, lower to middle Jurassic red sandstones of the Umphang Group in the Sibumasu Terrane were sampled at 21 sites in the Ratchaburi area (13.6E, 99.6E), Thailand. Stepwise thermal demagnetization by 680 C unblocked a pre-folding characteristic remanent magnetization. A mean direction of this component at 100% unfolding is Ds = 348.5, Is = 24.7, ?95 = 10.5, k = 10.7, N = 20, corresponding to an Early-Middle Jurassic pole of ? = 78.6N, ? = 10.6E (A95 = 9.3). Comparison of this direction with those reported from other localities of the Umphang Group (Kalaw, Mae Sot and North Trang Syncline localities) reveal variable declinations (between 348.5 and 44.7) for the Sibumasu Terrane. We ascribe this variation to differential tectonic deformation in the Sibumasu Terrane, as reflected from sinusoidal shaped structural features in the study area. The presence of such features in the granitic rocks indicates the occurrences of deformational activities after their intrusion, which took place in the period between 130 Ma and 51 Ma. The Sibumasu Terrane behaved as an independent fragment at a time when Indochina was undergoing a clockwise rotation and southward displacement, as a result of extrusion tectonics after the gigantic India-Asia collision. Taking into consideration a westerly deflected declination (D = 342.8) from the West Trang area in Peninsular Thailand, a counterclockwise rotation of 15 is estimated for the Sibumasu Terrane, as a result of continuous northward indentation of the Australian Plate into South Sundaland Block.

  18. Cosmic Spider is Good Mother

    NASA Astrophysics Data System (ADS)

    2006-04-01

    Hanging above the Large Magellanic Cloud (LMC) - one of our closest galaxies - in what some describe as a frightening sight, the Tarantula nebula is worth looking at in detail. Also designated 30 Doradus or NGC 2070, the nebula owes its name to the arrangement of its brightest patches of nebulosity that somewhat resemble the legs of a spider. This name, of the biggest spiders on Earth, is also very fitting in view of the gigantic proportions of the celestial nebula - it measures nearly 1,000 light years across! ESO PR Photo 11/06 ESO PR Photo 13b/06 Tarantula's Central Cluster, R136 The Tarantula nebula is the largest emission nebula in the sky and also one of the largest known star-forming regions in all the Milky Way's neighbouring galaxies. Located about 170,000 light-years away, in the southern constellation Dorado (The Swordfish), it can be seen with the unaided eye. As shown in this image obtained with the FORS1 multi-mode instrument on ESO's Very Large Telescope, its structure is fascinatingly complex, with a large number of bright arcs and apparently dark areas in between. Inside the giant emission nebula lies a cluster of young, massive and hot stars, denoted R 136, whose intense radiation and strong winds make the nebula glow, shaping it into the form of a giant arachnid. The cluster is about 2 to 3 million years old, that is, almost from 'yesterday' in the 13.7 billion year history of the Universe. Several of the brighter members in the immediate surroundings of the dense cluster are among the most massive stars known, with masses well above 50 times the mass of our Sun. The cluster itself contains more than 200 massive stars. ESO PR Photo 11/06 ESO PR Photo 13c/06 The Stellar Cluster Hodge 301 In the upper right of the image, another cluster of bright, massive stars is seen. Known to astronomers as Hodge 301, it is about 20 million years old, or about 10 times older than R136. The more massive stars of Hodge 301 have therefore already exploded as supernovae, blasting material away at tremendous speed and creating a web of entangled filaments. More explosions will come soon - in astronomical terms - as three red supergiants are indeed present in Hodge 301 that will end their life in the gigantic firework of a supernova within the next million years. ESO PR Photo 13d/06 ESO PR Photo 13d/06 Gas Pillars in Tarantula Nebula While some stars are dying in this spidery cosmic inferno, others are yet to be born. Some structures, seen in the lower part of the image, have the appearance of elephant trunks, not unlike the famous and fertile "Pillars of Creation" at the top of which stars are forming. In fact, it seems that stars form all over the place in this gigantic stellar nursery and in all possible masses, at least down to the mass of our Sun. In some places, in a marvellous recycling process, it is the extreme radiation from the hot and massive stars and the shocks created by the supernova explosions that has compressed the gas to such extent to allow stars to form. To the right and slightly below the central cluster, a red bubble is visible. The star that blows the material making this bubble is thought to be 20 times more massive, 130 000 times more luminous, 10 times larger and 6 times hotter than our Sun. A possible fainter example of such a bubble is also visible just above the large red bubble in the image. ESO PR Photo 13e/06 ESO PR Photo 13e/06 Red Bubbles in Tarantula Nebula Earlier colour composite images of the Tarantula nebula have been made with other instruments and/or filters at ESO's telescopes, e.g. PR Photo 05a/00 in visual light with FORS2 at the VLT at Paranal, and PR Photos 14a-g/02 and 34a-h/04 with the Wide-Field Imager at the ESO/MPG 2.2-m telescope at La Silla.

  19. Ductile Faults Control Seismogenic Movement on Oceanic Transforms

    NASA Astrophysics Data System (ADS)

    Lister, G. S.; Tkalcic, H.; Forster, M. A.; McClusky, S.

    2014-12-01

    Structural Geology is about 3D geometry and the symphony of kinematically-coordinated movement. In this case we discuss patterns of violent relative displacement inferred from focal plane data for earthquakes. Systematic stereographic analysis of centroid moment tensor data often shows well-defined orientation groups in scatterplots of fault plane normals and associated slip line vectors. These allow important geodynamic inferences, e.g., we can show that ductile faults control the geometry of oceanic transforms, and that normal fault earthquakes on spreading ridges are usually skewed with respect to adjacent transform faults. To explain this asymmetry requires finite rock strength, but it also means that it is not brittle failure that controls the orientation of oceanic transforms. This asymmetry also requires formation of tilt block geometries reminiscent of Basin-and-Range-style continental extension, systematic offset of earthquake hypocentres from the spreading ridge, and a general complexity in magma-fault interactions that is far beyond what might be expected if ocean-floor spreading is the result of dilating tension-mode fractures in dyke swarms. The role of ductile faulting should be given special mention because mostly it is argued that brittle faults are responsible for earthquakes. Yet many other examples of ductile faults in operation can be inferred, e.g., ductile faults associated with slab drop-off, where slab boudinage leads to extensional ductile faults and seismic activity driven by the pulling away of a relict slab, e.g., beneath the Hindu Kush. Another example might be found by close examination of the tectonic significance of the lowermost of the double (or paired) seismic zones such as can be seen in cross-sections of the subducting slab beneath Japan. The lowermost of the paired seismic zones may mark the locus of aseismic ductile shears or detachments formed by slumping of gigantic sheets of rock attempting to slide down the face of actively subducting slabs. Seismogenic activity may be driven by ductile faulting (again related to boudinage) of the relatively strong sheet of the subducting slab overlying this movement zone. The role of ductile faulting has been undervalued in earthquake generation, and this data suggests revision of seismotectonic doctrines may be necessary.

  20. Tvashtar in Motion

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This five-frame sequence of New Horizons images captures the giant plume from Io's Tvashtar volcano. Snapped by the probe's Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Jupiter earlier this year, this first-ever 'movie' of an Io plume clearly shows motion in the cloud of volcanic debris, which extends 330 kilometers (200 miles) above the moon's surface. Only the upper part of the plume is visible from this vantage point -- the plume's source is 130 kilometers (80 miles) below the edge of Io's disk, on the far side of the moon.

    The appearance and motion of the plume is remarkably similar to an ornamental fountain on Earth, replicated on a gigantic scale. The knots and filaments that allow us to track the plume's motion are still mysterious, but this movie is likely to help scientists understand their origin, as well as provide unique information on the plume dynamics.

    Io's hyperactive nature is emphasized by the fact that two other volcanic plumes are also visible off the edge of Io's disk: Masubi at the 7 o'clock position, and a very faint plume, possibly from the volcano Zal, at the 10 o'clock position. Jupiter illuminates the night side of Io, and the most prominent feature visible on the disk is the dark horseshoe shape of the volcano Loki, likely an enormous lava lake. Boosaule Mons, which at 18 kilometers (11 miles) is the highest mountain on Io and one of the highest mountains in the solar system, pokes above the edge of the disk on the right side.

    The five images were obtained over an 8-minute span, with two minutes between frames, from 23:50 to 23:58 Universal Time on March 1, 2007. Io was 3.8 million kilometers (2.4 million miles) from New Horizons; the image is centered at Io coordinates 0 degrees north, 342 degrees west.

    The pictures were part of a sequence designed to look at Jupiter's rings, but planners included Io in the sequence because the moon was passing behind Jupiter's rings at the time.

  1. Optimization of flow modeling in fractured media with discrete fracture network via percolation theory

    NASA Astrophysics Data System (ADS)

    Donado-Garzon, L. D.; Pardo, Y.

    2013-12-01

    Fractured media are very heterogeneous systems where occur complex physical and chemical processes to model. One of the possible approaches to conceptualize this type of massifs is the Discrete Fracture Network (DFN). Donado et al., modeled flow and transport in a granitic batholith based on this approach and found good fitting with hydraulic and tracer tests, but the computational cost was excessive due to a gigantic amount of elements to model. We present in this work a methodology based on percolation theory for reducing the number of elements and in consequence, to reduce the bandwidth of the conductance matrix and the execution time of each network. DFN poses as an excellent representation of all the set of fractures of the media, but not all the fractures of the media are part of the conductive network. Percolation theory is used to identify which nodes or fractures are not conductive, based on the occupation probability or percolation threshold. In a fractured system, connectivity determines the flow pattern in the fractured rock mass. This volume of fluid is driven through connection paths formed by the fractures, when the permeability of the rock is negligible compared to the fractures. In a population of distributed fractures, each of this that has no intersection with any connected fracture do not contribute to generate a flow field. This algorithm also permits us to erase these elements however they are water conducting and hence, refine even more the backbone of the network. We used 100 different generations of DFN that were optimized in this study using percolation theory. In each of the networks calibrate hydrodynamic parameters as hydraulic conductivity and specific storage coefficient, for each of the five families of fractures, yielding a total of 10 parameters to estimate, at each generation. Since the effects of the distribution of fault orientation changes the value of the percolation threshold, but not the universal laws of classical percolation theory, the latter is applicable to such networks. Under these conditions, percolation theory permit us to reduced the number of elements (90% in average) that form clusters of the 100 DFNs, preserving the so-called backbone. In this way the calibration runs in these networks changed from several hours to just a second obtaining much better results.

  2. Acromegaly resolution after traumatic brain injury: a case report

    PubMed Central

    2014-01-01

    Introduction Anterior hypopituitarism is a common complication of head trauma, with a prevalence of 30% to 70% among long-term survivors. This is a much higher frequency than previously thought and suggests that most cases of post-traumatic hypopituitarism remain undiagnosed and untreated. Symptoms of hypopituitarism are very unspecific and very similar to those in traumatic brain injury patients in general, which makes hypopituitarism difficult to diagnose. The factors that predict the likelihood of developing hypopituitarism following traumatic brain injury remain poorly understood. The incidence of a specific hormone deficiency is variable, with growth hormone deficiency reported in 18% to 23% of cases. Case presentation A 23-year-old Hispanic man with a 2-year history of hypertension and diabetes presented with severe closed-head trauma producing diffuse axonal injury, subarachnoid hemorrhage and a brain concussion. A computed tomography scan showed a pituitary macroadenoma. The patient has clinical features of acromegaly and gigantism without other pituitary hyperfunctional manifestations or mass effect syndrome. A short-term post-traumatic laboratory test showed high levels of insulin like growth factor 1 and growth hormone, which are compatible with a growth hormoneproducing pituitary tumor. At the third month post-trauma, the patients levels of insulin like growth factor 1 had decreased to low normal levels, with basal low levels of growth hormone. A glucose tolerance test completely suppressed the growth hormone, which confirmed resolution of acromegaly. An insulin tolerance test showed lack of stimulation of growth hormone and cortisol, demonstrating hypopituitarism of both axes. Conclusion Even though hypopituitarism is a frequent complication of traumatic brain injury, there are no reports in the literature, to the best of my knowledge, of patients with hyperfunctional pituitary adenomas, such as growth hormoneproducing adenoma, that resolved after head trauma. A clear protocol has not yet been established to identify which patients should be screened for hypopituitarism. Predictive factors that might determine the likelihood of developing post-traumatic hypopituitarism have not been clearly established, but there is no evidence of the presence of pituitary adenomas as a risk factor in otherwise healthy patients. PMID:25182385

  3. Nanotechnology in agriculture: prospects and constraints

    PubMed Central

    Mukhopadhyay, Siddhartha S

    2014-01-01

    Attempts to apply nanotechnology in agriculture began with the growing realization that conventional farming technologies would neither be able to increase productivity any further nor restore ecosystems damaged by existing technologies back to their pristine state; in particular because the long-term effects of farming with miracle seeds, in conjunction with irrigation, fertilizers, and pesticides, have been questioned both at the scientific and policy levels, and must be gradually phased out. Nanotechnology in agriculture has gained momentum in the last decade with an abundance of public funding, but the pace of development is modest, even though many disciplines come under the umbrella of agriculture. This could be attributed to: a unique nature of farm production, which functions as an open system whereby energy and matter are exchanged freely; the scale of demand of input materials always being gigantic in contrast with industrial nanoproducts; an absence of control over the input nanomaterials in contrast with industrial nanoproducts (eg, the cell phone) and because their fate has to be conceived on the geosphere (pedosphere)-biosphere-hydrosphere-atmosphere continuum; the time lag of emerging technologies reaching the farmers field, especially given that many emerging economies are unwilling to spend on innovation; and the lack of foresight resulting from agricultural education not having attracted a sufficient number of brilliant minds the world over, while personnel from kindred disciplines might lack an understanding of agricultural production systems. If these issues are taken care of, nanotechnologic intervention in farming has bright prospects for improving the efficiency of nutrient use through nanoformulations of fertilizers, breaking yield barriers through bionanotechnology, surveillance and control of pests and diseases, understanding mechanisms of host-parasite interactions at the molecular level, development of new-generation pesticides and their carriers, preservation and packaging of food and food additives, strengthening of natural fibers, removal of contaminants from soil and water, improving the shelf-life of vegetables and flowers, clay-based nanoresources for precision water management, reclamation of salt-affected soils, and stabilization of erosion-prone surfaces, to name a few. PMID:25187699

  4. About universes with scale-related total masses and their abolition of presently outstanding cosmological problems

    NASA Astrophysics Data System (ADS)

    Fahr, H. J.; Heyl, M.

    2007-02-01

    The most recently celebrated cosmological implications of the cosmic microwave background studies with WMAP (2006), though fascinating by themselves, do, however, create some extremely hard conceptual challenges for the present-day cosmology. These recent extremely refined WMAP observations seem to reflect a universe which was extremely homogeneous at the recombination age and thus is obviously causally closed at the time of the cosmic recombination era. From the very tiny fluctuations apparent at this early epoch the presently observable nonlinear cosmic density structures can, however, only have grown up, if in addition to a mysteriously high percentage of dark matter an even higher percentage of dark energy is admitted as drivers of the cosmic evolution. The required dark energy density, on the other hand, is nevertheless 120 orders of magnitude smaller then the theoretically calculated value. These are outstanding problems of present day cosmology onto which we are looking here under new auspices. We shall investigate in the following, up to what degree a universe simply abolishes all these outstanding problems in case it reveals itself as an universe of constant total energy. As we shall show basic questions like: How could the gigantic mass of the universe of about 1080 proton masses at all become created? - Why is the presently recognized and obviously indispensable cosmic vacuum energy density so terribly much smaller than is expected from quantum theoretical considerations, but nevertheless terribly important for the cosmic evolution? - Why is the universe within its world horizon a causally closed system? - , can perhaps simply be answered, when the assumption is made that the universe has a constant total energy with the consequence that the total mass density of the universe (matter and vacuum) scales with R_u\\-2. Such a scaling of matter and vacuum energy abolishes the horizon problem, and the cosmic vacuum energy density can easily be reconciled with its theoretical expectation values. In this model the mass of the universe increases linearly with the world extension R_u and can grow up from a Planck mass as a vacuum fluctuation.

  5. Brazilian and Mexican experiences in the study of incipient domestication

    PubMed Central

    2014-01-01

    Background Studies of domestication enables a better understanding of human cultures, landscape changes according to peoples purposes, and evolutionary consequences of human actions on biodiversity. This review aimed at discussing concepts, hypotheses, and current trends in studies of domestication of plants, using examples of cases studied in regions of Mesoamerica and Brazil. We analyzed trends of ethnobiological studies contributing to document processes of domestication and to establish criteria for biodiversity conservation based on traditional ecological knowledge. Methods Based on reviewing our own and other authors studies we analyzed management patterns and evolutionary trends associated to domestication occurring at plant populations and landscape levels. Particularly, we systematized information documenting: ethnobotanical aspects about plant management and artificial selection mechanisms, morphological consequences of plant management, population genetics of wild and managed plant populations, trends of change in reproduction systems of plants associated to management, and other ecological and physiological aspects influenced by management and domestication. Results Based on the analysis of study cases of 20 native species of herbs, shrubs and trees we identified similar criteria of artificial selection in different cultural contexts of Mexico and Brazil. Similar evolutionary trends were also identified in morphology (selection in favor of gigantism of useful and correlated parts); organoleptic characteristics such as taste, toxicity, color, texture; reproductive biology, mainly breeding system, phenological changes, and population genetics aspects, maintenance or increasing of genetic diversity in managed populations, high gene flow with wild relatives and low structure maintained by artificial selection. Our review is a first attempt to unify research methods for analyzing a high diversity of processes. Further research should emphasize deeper analyses of contrasting and diverse cultural and ecological contexts for a better understanding of evolution under incipient processes of domestication. Conclusion Higher research effort is particularly required in Brazil, where studies on this topic are scarcer than in Mexico but where diversity of human cultures managing their also high plant resources diversity offer high potential for documenting the diversity of mechanisms of artificial selection and evolutionary trends. Comparisons and evaluations of incipient domestication in the regions studied as well as the Andean area would significantly contribute to understanding origins and diffusion of the experience of managing and domesticating plants. PMID:24694009

  6. The Assembly of Eastern North America: Using Garnet Zoning to Decipher the Potomac Terrane

    NASA Astrophysics Data System (ADS)

    Stodden, D.; Melson, W. G.

    2001-12-01

    The Sykesville Formation, the focus of this study, is in the easternmost Potomac Terrain between Roosevelt Island and Chain Bridge in the Potomac River Gorge on the Virginia side. The Potomac is one of many as yet poorly understood terranes speculatively added to the late Precambrian margin of North America. The remarkably voluminous Sykesville formation extends 125 km and is typically at least 3 km thick. Hopson (1964) recognized it as a gigantic slump deposit that grades westward into the turbidites of the Wissahickon Formation. The work of Hopson has been expanded upon in the many publications of A. A. Drake, Jr. with additional mapping in northern Virginia. The age of the Sykesville protolith is probably over 500 ma and was obducted on to the North American continent probably over 400 million years ago by collision with a deep-sea trench marginal to a mountainous continent or microcontinent. The source area for the protolith in our study area is overwhelmingly continental. Quartz veins and what appear to be metaorthoquartzite bed are common in the Sykesville. The presumed metaorthoquartzite beds was examined by cathodoluminescence. With this analysis, we discovered relict sand grains preserved in a quartz sample. This presents an enigma: the presence of a pure, mature quartz sediment interbedded in an immature feldspathic sandy slump deposit. Were there two quite different source areas feeding into the protolith? We examined garnets using electron microprobe analysis to examine the P-T history of the Sykesville. The garnets show simple zoning patterns, most clearly, as usual, in MnO. Compositional profiles suggest a single episode of metamorphism followed by retrogression, presumably during uplift and erosion after obduction. The age interval of this metamorphism is uncertain but was latest Precambrian or early Cambrian (Penobscot Orogeny). Future analysis of the chemical composition of the garnets will tell us more about the pressures and temperatures that the garnets reached during metamorphism attendant to obduction of the Potomac Terrane to North America. We thank Amelia Logan, Jim Rougvie and Sorena Sorensen of the Smithsonian for their assistance with this project.

  7. Variable Rupture Mode at Subduction Zones Around the Pacific

    NASA Astrophysics Data System (ADS)

    Satake, K.

    2005-12-01

    The enormity of the 2004 Sumatra-Andaman earthquake, in comparison with 19th- and 20th-century earthquakes in its rupture area, serves as a reminder that a subduction zone may produce earthquakes larger than those in recorded in the past. Historical record and paleoseismological data show that variability in rupture mode is characteristic of some subduction zones. Infrequent, gigantic earthquakes predominate in geologic records, while historic data tell of more frequent, smaller earthquakes. This implies that along the Cascadia subduction zone, great (M > 8) earthquake can occur more frequently than estimated from paleoseismological record. Like the 2004 Sumatra-Andaman earthquake, the giant 1960 Chilean earthquake (Mw 9.5) was unusually large. Historical predecessors of the 1960 earthquake occurred in 1837, 1737, and 1575. However, midway along the 1960 rupture, only the 1575 event produced geologic records of subsidence and tsunami as obvious as those of 1960. The 1837 and 1737 ruptures were probably small, at least at this latitude (Cisternas et al., 2005). Along the Nankai trough of southwest Japan, recurrence of semi-regular earthquakes has been documented in the 1300 years' written history, with an indication of some variability. The easternmost Suruga trough was ruptured in 1854 but not in 1944, leaving a seismic gap for the anticipated Tokai earthquake. The 1707 earthquake ruptured both Nankai and Tokai sources that ruptured separately in 1854 and in 1944 and 1946. The 1605 earthquake seems to be an unusual tsunami earthquake. Near Tokyo, along the Sagami trough, historical records and marine terraces show two types of large earthquakes (1923 type and 1703 type; Shishikura, 2003); their average recurrence intervals are estimated geologically as several hundred years and a few thousand years, respectively. Earthquakes larger than Mw 8.2 can happen along the southern Kuril trench even though they are unknown from the 200-year written history of Hokkaido. Plate-boundary earthquakes close to M 8, at intervals of 100 years or less, had been considered characteristic in this subduction zone. The 2003 Tokachi-oki earthquake (M 8.0), for instance, was preceded by similar earthquakes, from slightly different source areas, in 1952 and 1843. However, tsunami deposits show that unusually large tsunamis repeated at intervals averaging about 500 yr, with the most recent event in the 17th century (Hirakawa et al., 2000; Nanayama et al., 2003). The inferred inundation area is much wider than those typical earthquakes, and is best explained by earthquakes that broke more than one of the historical segments. Only these multi-segment earthquakes triggered deep postseismic creep that produced decimeters of coastal uplift (Sawai et al., 2004).

  8. Sotos syndrome and scoliosis surgical treatment: a 10-year follow-up.

    PubMed

    Corrado, Romina; Wilson, Alejandra Francheri; Tello, Carlos; Noel, Mariano; Galaretto, Eduardo; Bersusky, Ernesto

    2011-07-01

    Sotos syndrome is caused by a gene deletion with an autosomal dominant pattern of inheritance. Cerebral gigantism, hypotonia and joint hyperextensibility are characteristic features of this syndrome. A percentage of these patients develop progressive scoliosis early in life. In the literature, few studies on the evolution of scoliosis in Sotos syndrome have been published. We retrospectively evaluated eight patients diagnosed with Sotos syndrome and scoliosis treated at the Garrahan Children Hospital between 1988 and March 2009. Clinical charts and imaging studies were assessed. Eight patients (19%) presented with scoliosis and seven of them (87.5%) required surgical treatment. The mean follow-up was 9.5years (range 3-18). Mean age at first consultation was 5.2years (range 1.1-11.2). Mean Cobb angle for scoliosis at first consultation was 34.3 (range 20-42) and the mean Cobb angle for kyphosis was 45.6 (range 30-90). Mean age at surgery was 11.2years (range 3.7-18.10). The surgical procedures performed were instrumented posterior arthrodesis, alone or combined with anterior arthrodesis, instrumented anterior arthrodesis, while one patient is currently in treatment with growing rods. Preoperative mean Cobb angle for scoliosis was 72.3 (range 54-130) and for kyphosis was 59.8 (range 30-108); postoperative mean Cobb angle for scoliosis was 45.5 (range 6-90) and for kyphosis was 40.2 (range 30-80). There were three early complications (pleural effusion in two cases and death due to sepsis in one) and two late complications (kyphosis above the instrumentation area and dislodgement of the proximal hooks). Incidence of scoliosis in Sotos syndrome is high and thus close monitoring of patients with Sotos syndrome during growth is important for early detection of this entity. Joint hyperextensibility and hypotonia that are characteristic of the syndrome should be considered at the moment of surgery to avoid short fusions. PMID:21225435

  9. Investigation of Miocene volcanic structures on Lesbos using remote sensing techniques

    NASA Astrophysics Data System (ADS)

    St. Seymour, K.; Kouli, M.; Vamvoukakis, C.; Lamera, S.

    2003-04-01

    The island of Lesbos, located in northeastern Aegean Sea, just offshore Asia Minor, is mostly covered by Miocene calcalkaline and predominantly shoshonitic volcanic products. Pyroclastic activity was intense; in the eastern part of the island outcrops the Polychnitos Ignimbrite which most probably continues on the proximal islets and shores of Asia Minor near the ancient city of Kidoniai. The western part of Lesbos, in the Sigri National Park, is covered by the Sigri Pyroclastic Formation, the host to the renown lithified forest of gigantic conifers resembling sequoias. This prolific 21.5 - 17 my volcanic activity requires well-developed subvolcanic magma chambers and their surfacial expression in the form of sizable caldera structures, two of which they have been inferred from intense alteration zones by Pe-Piper (1980b, 1998). However, appreciation of the actual geometry and number of these volcanic structures is severely limited by erosion and fault tectonics. Remote sensing was combined with field geology and geochemical methods. LANDSAT-TM and SPOT-PAN satellite images and the Digital Elevation Model of the targeted areas were digitally processed in order to reveal specific geological characteristics related with caldera structures such as radial and ring faults, areas of hydrothermal alteration, drainage network, and lava domes, both internal and external to caldera structures. With the aim of creating colorful pictures in order to convey as much spectral information as possible and to enhance the outlines of the Lesbos volcanic features we performed decorrelation stretching of the seven bands of the Landsat - TM imagery, and we finally choose the 5,7,3 (R,G,B) false color composite as the most informative for the geological and lithological interpretation. A slope map with a resolution of 1o was produced from the DEM of the study area. As a result of our investigations we have recognized six caldera structures of which four new ones. The highlights of these investigations are: (a) The Stipsi Caldera is related with high sulphidation zones and probably volcanogenic precious metal mineralization, (b) The Polychnitos ignimbrite continues on the proximal shore of Asia Minor, (c) The source of the Sigri pyroclastics is a (14x10 km) large caldera structure, the Sigri Caldera, that encloses the previously recognized Vatoussa structure (nested caldera).

  10. Animal Tails

    NSDL National Science Digital Library

    Sohmer, Rachel.

    2003-01-01

    Call it tail envy. With only a vestigial nub to show for ourselves, perhaps it's no wonder that animal tails capture our attention. The following Web sites present some of the more interesting tails to be found in the animal kingdom. The first Web site contains a recent article from Discovery News describing new findings that at least one species of scorpion produces two distinct types of tail venom, which have completely different effects on their victims (1). The next site from Singapore Zoological Gardens introduces the cebids (our New World monkey cousins), some of which have amazing prehensile tails that are used like a fifth limb (2). The rattlesnake is another famously-tailed creature, highlighted in the following site from the Arizona-Sonora Desert Museum (3). The site covers the main aspects of rattlesnake natural history, including a section on how the rattle forms. The Great Plains Nature Center in Wichita, Kansas, offers a Web page devoted to the beaver, including tail trivia and an audio clip of a resident beaver surprised in his den at the Kansas Wildlife Exhibit (4). Anyone who has witnessed the freakishly fascinating spectacle of a gecko leaving its tail behind to distract a would-be predator will appreciate this brief bio of the Tokay gecko, presented by ReptileCenter.com, the Herpetologist's Portal (5). Stacy's Wag'N'Train -- offering dog-training classes in San Jose, California -- provides this online guide to dog body language, which would have a very limited vocabulary without the tail (6). So, how did the peacock get its tail? It's a simple question that has driven zoologists crazy for over a century. The next Web site (7) contains an in-depth article on the subject from the Independent (London), offered through National Geographic News. And finally, the bizarre gulper eel -- able to tie its tail in several knots -- gets is own Web page on Pangea, the Web server for the Department of Educational Leadership and Technology at Southeastern Louisiana University (8). This deep-sea curiosity uses its bioluminescent tail tip to lure hapless prey into its impossibly gigantic mouth.

  11. Anti-inflammatory, antioxidant, and antimicrobial activities of Cocos nucifera var. typica

    PubMed Central

    2013-01-01

    Background Teas from the husk fiber of Cocos nucifera are used in the folk medicine to treat arthritis and other inflammatory processes. Some works show that some varieties have biological activities. However, one of the main variety of the species, C. nucifera var. typica, known in Brazil as gigante, was not studied yet. Thus, this study evaluates if this variety has the anti-inflammatory and antimicrobial activities already reported in other varieties. Methods C. nucifera aqueous crude extract (10, 50, and 100 mg/kg) and the reference drugs morphine (1 mg/kg) and acetylsalicylic acid (100 mg/kg) were evaluated in models of inflammation (formalin-induced licking and subcutaneous air pouch). The antioxidant activity was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) photometric assay and compared with those of the standards (quercetin, rutin, and ascorbic acid). The extract was also screened against Candida albicans, Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), in the agar diffusion method. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the broth micro-dilution assay. Activities of combinations of the extract and antibiotics (methicillin or vancomycin) against MRSA were evaluated using checkerboard assays. Results The extract significantly inhibited the time that the animals spent licking the formalin-injected paws (second phase). The extract also inhibited the inflammatory process induced by subcutaneous carrageenan injection by reducing cell migration, protein extravasation, and TNF-? production. Additionally, the extract showed an antioxidant potential in vitro as good as standards in their antioxidant activity. The extract was active only against S. aureus and MRSA. MIC and the bactericidal concentrations were identical (1,024 ?g/ml). The extract and methicillin acted synergistically against the clinical MRSA isolate, whereas an indifferent effect was detected when the extract was combined with vancomycin. Conclusions The extract exhibits anti-inflammatory activity through the inhibition of the cell migration. The mixture of extract constituents and methicillin could lead to the development of a new combination antibiotic against MRSA infections. PMID:23680079

  12. Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal; Meral Ozel, Nurcan

    2015-04-01

    Accurate earthquake source parameters are essential for any tsunami hazard assessment and mitigation, including early warning systems. Complex tectonic setting makes the a priori accurate assumptions of earthquake source parameters difficult and characterization of the faulting type is a challenge. Information on tsunamigenic sources is of crucial importance in the Eastern Mediterranean and its Connected Seas, especially considering the short arrival times and lack of offshore sea-level measurements. In addition, the scientific community have had to abandon the paradigm of a ''maximum earthquake'' predictable from simple tectonic parameters (Ruff and Kanamori, 1980) in the wake of the 2004 Sumatra event (Okal, 2010) and one of the lessons learnt from the 2011 Tohoku event was that tsunami hazard maps may need to be prepared for infrequent gigantic earthquakes as well as more frequent smaller-sized earthquakes (Satake, 2011). We have initiated an extensive modeling study to perform a deterministic Tsunami Hazard Analysis for the Eastern Mediterranean and its Connected Seas. Characteristic earthquake source parameters (strike, dip, rake, depth, Mwmax) at each 0.5 x 0.5 size bin for 0-40 km depth (total of 310 bins) and for 40-100 km depth (total of 92 bins) in the Eastern Mediterranean, Aegean and Black Sea region (30N-48N and 22E-44E) have been assigned from the harmonization of the available databases and previous studies. These parameters have been used as input parameters for the deterministic tsunami hazard modeling. Nested Tsunami simulations of 6h duration with a coarse (2 arc-min) grid resolution have been simulated at EC-JRC premises for Black Sea and Eastern and Central Mediterranean (30N-41.5N and 8E-37E) for each source defined using shallow water finite-difference SWAN code (Mader, 2004) for the magnitude range of 6.5 - Mwmax defined for that bin with a Mw increment of 0.1. Results show that not only the earthquakes resembling the well-known historical earthquakes such as AD 365 or AD 1303 in the Hellenic Arc, but also earthquakes with lower magnitudes do constitute to the tsunami hazard in the study area, as indicated also by historical information. A simplified tsunami hazard map is also presented. This work is partially funded by project ASTARTE - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839.

  13. Landslide disaster avoidance: learning from Leyte

    NASA Astrophysics Data System (ADS)

    Davies, T. R.

    2006-12-01

    On 17 February 2006 a gigantic rockslide triggered a debris avalanche that overran the barangay Guinsaugon, St. Bernard in Southern Leyte Province, Philippines, burying 154 victims, with 990 missing including 246 school children. Even with satellite imagery, GIS-based landslide susceptibility modelling and real-time meteorological and seismic data analysis, scientific prediction of every potentially fatal landslide is not possible in most parts of the world. This is particular the case in steep, unstable, densely-populated country in which heavy rain is common. So how can further events of this type be prevented from turning into disasters? A number of precursory phenomena were noted by local inhabitants at Guinsaugon: a crack around the slope that failed was noticed in May 2005; coconut trees near the northern foot of the landslide scarp began to lean increasingly in the down-slope direction in December 2005; a slope around the northern edge of the 17 February 2006 landslide scarp failed on December 17, 2005; in the 9 days prior to the rockslide, 640 mm of rain fell; 450 mm in a 3-day period. Such phenomena are commonly reported by local inhabitants before large landslides (e.g. Elm, Mayunmarca, and many others). In many cases, therefore, it is in principle possible for local people to avoid the consequences of the landslide if they know enough to act appropriately in response to the precursory phenomena. For this possibility to be realized, appropriate information must be provided to and assimilated by the local population. Useful ways of achieving this include pamphlets, video, TV and radio programs and visits from civil defence personnel. The information must be properly presented; scientific language will be ineffective. A communication pyramid, leading from government agencies to local leaders, can facilitate the rapid availability of the information to all potentially susceptible communities. If science can determine those areas not vulnerable to landslide disasters, that is potentially advantageous. However the next landslide may be next week, so the information initiative cannot wait for science: lives will not be saved while the pamphlets are in a box. Keywords: Leyte landslide; precursory phenomena; disaster avoidance; community awareness.

  14. Accretionary history of the Altai-Mongolian terrane: perspectives from granitic zircon U-Pb and Hf-isotope data

    NASA Astrophysics Data System (ADS)

    Cai, Keda; Sun, Min; Xiao, Wenjiao

    2014-05-01

    The Central Asian Orogenic Belt (CAOB) consists of many tectonic terranes with distinct origin and complicated evolutionary history. Understanding of individual block is crucial to reconstruct the geodynamic history of the gigantic accetionary collage. This study presents zircon U-Pb ages and Hf isotopes for the granitoid rocks in the Russian Altai mountain range (including Gorny Altai, Altai-Mongolian terrane and CTUS suture zone between them), in order to clarify the timing of granitic magmatism, source nature, continental crustal growth and tectonic evolution. Our dating results suggest that granitic magmatism of the Russian Altai mountain range occurred in three major episodes including 445~429 Ma, 410~360 Ma and ~241 Ma. Most of the zircons within the Paleozoic granitoids present comparable positive ?Hf(t) values and Neoproterozoic crustal model ages, which favor the interpretation that the juvenile crustal materials produced in the early stage of CAOB were probably dominant sources for the Paleozoic magmatism in the region. The inference is also supported by widespread occurrence of short-lived juvenile materials including ophiolites, seamount relics and arc assemblages in the north CAOB. Consequently, the Paleozoic massive granitic rocks maybe not represent continental crustal growth at the time when they were emplaced, but rather record reworking of relatively juvenile Proterozoic crustal rocks although mantle-derived mafic magma was possibly involved to sever as heat engine during granitic magma generation. The Early Triassic granitic intrusion may be product in an intra-plate environment, as the case of same type rocks in the adjacent areas. The positive ?Hf(t) values (1.81~7.47) and corresponding Hf model ages (0.80~1.16 Ga) together with evidence of petrology are consistent with the interpretation that the parental magma of the Triassic granitic intrusion was produced from enriched mantle-derived sources under an usually high temperature condition which is likely due to basaltic magma that underplated the lower crust. Our data combined with evidence of the regional geology enable us to conclude that the Gorny Altai and Altai-Mongolian terranes possibly have similar tectonic natures, but represent two separate accretionary systems before Devonian collision. The accretion and amalgamation processes resulted in the Paleozoic granitoid magmatism and caused the two terranes to merge as a composite tectonic domain at the Siberian continental margin.

  15. E-CANES: A Research Network dedicated to Electromagnetic Coupling of the Atmosphere With Near-Earth Space

    NASA Astrophysics Data System (ADS)

    Hanuise, C.; Blanc, E.; Crosby, N.; Ebert, U.; Mareev, E.; Neubert, T.; Rothkaehl, H.; Santolik, O.; Yair, Y.; Gille, P.

    2008-12-01

    Transient luminous events in the stratosphere and mesosphere, the sprites, elves, blue jets and gigantic jets, are observed above intense thunderstorms in association with particularly intense lightning discharges. Their recent discovery (1989) offers an opportunity to study the fundamental process of the electric discharge under the different conditions of the troposphere (lightning), stratosphere (blue jets) and the mesosphere (sprites) and the coupling between these regions by electric and magnetic fields. It further facilitates studies of the more general questions of thunderstorm effects on the atmosphere and the role of thunderstorms in a changing climate. New space missions will be launched in the coming years to study the various effects of thunderstorms. They will focus on transient luminous events, the generation of relativistic electron beams in discharges, and the perturbation to the atmosphere, ionosphere and magnetosphere of lightning, transient luminous events, water vapour transport and gravity waves. The missions are the French micro-satellite TARANIS, the ESA ASIM payload on board the International Space Station and the Japanese Sprite Sat mission. These highly interdisciplinary missions will result in a wealth of new data, which require knowledge based capacity building to underpin the observations with improved statistical data analysis and theoretical modelling. We are therefore establishing a global framework for research on thunderstorm processes and their effect on the atmosphere, in particular (1) the fundamental process of the electric discharge as manifested in the stratosphere and mesosphere as sprites and jets, (2) the relationship between cosmic rays, lightning discharges, transient luminous events and terrestrial gamma ray flashes, and (3) the environmental impact of the above physical processes, and thunderstorms in general, on the atmosphere and near-Earth space. The first step has been the creation of the European research group (GDRE) dubbed E-CANES (Electromagnetic Coupling of the Atmosphere with the Near-Earth Space). It complements in a synergistic way the former EU Research Training Network 'Coupling of Atmospheric Layers', the existing COST action on 'The physics of lightning flash and its effects', the ASIM Topical Team, and other programs. The main objective of E-CANES is to initiate and promote coordination activities towards a global research community on the subject. The first actions include the establishment of an organization for coordinating ground, balloon and aircraft observation campaigns, the creation of a community-wide mailing list and website, and the promotion and coordination of joint activities with other structures - to include new communities and to avoid the duplication of meetings and workshops.

  16. Solar and Drag Sail Propulsion: From Theory to Mission Implementation

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Alhorn, Dean; Boudreaux, Mark; Casas, Joe; Stetson, Doug; Young, Roy

    2014-01-01

    Solar and drag sail technology is entering the mainstream for space propulsion applications within NASA and around the world. Solar sails derive propulsion by reflecting sunlight from a large, mirror- like sail made of a lightweight, reflective material. The continuous sunlight pressure provides efficient primary propulsion without the expenditure of propellant or any other consumable, allowing for very high V maneuvers and long-duration deep space exploration. Drag sails increase the aerodynamic drag on Low Earth Orbit (LEO) spacecraft, providing a lightweight and relatively inexpensive approach for end-of-life deorbit and reentry. Since NASA began investing in the technology in the late 1990's, significant progress has been made toward their demonstration and implementation in space. NASA's Marshall Space Flight Center (MSFC) managed the development and testing of two different 20-m solar sail systems and rigorously tested them under simulated space conditions in the Glenn Research Center's Space Power Facility at Plum Brook Station, Ohio. One of these systems, developed by L'Garde, Inc., is planned for flight in 2015. Called Sunjammer, the 38m sailcraft will unfurl in deep space and demonstrate solar sail propulsion and navigation as it flies to Earth-Sun L1. In the interim, NASA MSFC funded the NanoSail-D, a subscale drag sail system designed for small spacecraft applications. The NanoSail-D flew aboard the Fast Affordable Science and Technology SATellite (FASTSAT) in 2010, also developed by MSFC, and began its mission after it was was ejected from the FASTSAT into Earth orbit, where it remained for several weeks before deorbiting as planned. NASA recently selected two small satellite missions as part of the Advanced Exploration Systems (AES) Program, both of which will use solar sails to enable their scientific objectives. Lunar Flashlight, managed by JPL, will search for and map volatiles in permanently shadowed Lunar craters using a solar sail as a gigantic mirror to steer sunlight into the shaded craters. The Near Earth Asteroid (NEA) Scout mission will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. Both are planned for launch in 2017. As the technology matures, solar sails will increasingly be used to enable science and exploration missions that are currently impossible or prohibitively expensive using traditional chemical and electric rockets. For example, the NASA Heliophysics Decadal Survey identifies no less than three such missions for possible flight before the mid-2020's. Solar sail propulsion technology is no longer an intesting theoretical possibility; it has been demonstrated in space and is now a critical technology for science and solar system exploration.

  17. Changing seasonality patterns in Central Europe from Miocene Climate Optimum to Miocene Climate Transition deduced from the Crassostrea isotope archive

    NASA Astrophysics Data System (ADS)

    Harzhauser, Mathias; Piller, Werner E.; Mllegger, Stefan; Grunert, Patrick; Micheels, Arne

    2011-03-01

    The Western Tethyan estuarine oyster Crassostrea gryphoides is an excellent climate archive due to its large size and rapid growth. It is geologically long lived and allows a stable isotope-based insight into climatic trends during the Miocene. Herein we utilised the climate archive of 5 oyster shells from the Miocene Climate Optimum (MCO) and the subsequent Miocene Climate Transition (MCT) to evaluate changes of seasonality patterns. MCO shells exhibit highly regular seasonal rhythms of warm-wet and dry-cool seasons. Optimal conditions resulted in extraordinary growth rates of the oysters. ? 13C profiles are in phase with ? 18O although phytoplankton blooms may cause a slight offset. Estuarine waters during the MCO in Central Europe display a seasonal temperature range of c. 9-10 C. Absolute water temperatures have ranged from 17 to 19 C during cool seasons and up to 28 C in warm seasons. Already during the early phase of the MCO, the growth rates are distinctly declining, although gigantic and extremely old shells have been formed at that time. Still, a very regular and well expressed seasonality is dominating the isotope profiles, but episodically occurring extreme climate events influence the environments. The seasonal temperature range is still c. 9 C but the cool season temperature seems to be slightly lower (16 C) and the warm season water temperature does not exceed c. 25 C. In the later MCT at c. 12.5-12.0 Ma the seasonality pattern is breaking down and is replaced by successions of dry years with irregular precipitation events. No correlation between ? 18O and ? 13C is documented maybe due to a suboptimal nutrition level which would explain the low growth rates and small sizes. The amplitude of seasonal temperature range is decreasing to 5-8 C. No clear cooling trend can be postulated for that time as the winter season water temperatures range from 15 to 20 C. This may point to unstable precipitation rhythms on a multi-annual to decadal scale as main difference between MCO and MCT climates in Central Europe instead of a simple temperature decline scenario.

  18. Link between climate and himalayan continental discharge for the last 800ka

    NASA Astrophysics Data System (ADS)

    Gourlan, A. T.; Chauvel, C.; Garon, M.; Meynadier, L.; Allegre, C. J.

    2010-12-01

    The quaternary era is characterized by large glacial-interglacial cycles, which have caused perturbations in the global oceanic circulation and in the continental rainfalls inducing changes in the discharge of rivers. The Bengal Gulf is presently a very attractive case to study theses changes because in this gigantic fan are accumulated the sediments eroded from the Himalayan mountain range through time which have been transported by the two major rivers, the Ganges and the Brahmaputra. The study of the marine sediments in the Bengal Gulf appears therefore as an ideal target to understand the relationship between the Himalayan erosion, the Indian Monsoon regime and the marine sedimentary record. The residence times of Nd and Hf (? 1000 years) being shorter than the mixing time of the global ocean, it is possible to identify the source provenances, the intensity of weathering on the continents as well as changes in oceanic paleocirculation, extracting both isotopes from marine sediments (detrital, coatings and carbonates fractions). Previous work using the seawater Nd isotopic composition recorded in coatings and carbonates fractions of marine sediments from ODP Site 758 in the Northern Bay of Bengal, showed a covariation between ?Nd and ?18O during the last 800 ka (Gourlan et al., 2010). A simple quantitative binary mixing model between fresh water from Himalaya rivers with Indian Ocean water explains this ?Nd variations and suggests that the summer monsoon rain in Himalaya was more intense during interglacial than glacial periods. Here we present new Nd data obtained on the detrital fraction of the same marine sediments for the last 800ka. Results show that variations of the detrital Nd isotopic composition are smaller than those of seawater, highlighting minor Nd isotopic changes of the detrital sources. Consequently, it is possible to better constrain the Nd Himalayan contribution estimating the mass fraction of Nd from Himalayan river water at Site 758 and its isotopic composition through the Glacial-interglacial alternance. These results help better constrain the mixing model mentioned above by providing a tight control on the composition of the continental input. A. T. Gourlan, L. Meynadier, C.J. Allgre, P. Tapponnier, J-L Birck and J-L Joron. Northern Hemisphere climate control of the Bengali rivers discharge during the past 4 Ma. Quaternary Science Reviews, Volume 29, Issues 19-20, September 2010, 2484-2498.

  19. The Italian drilling project of the Mont Blanc road tunnel in the late fifties: an example of no geological care and lack of ethics in carrying out a big work.

    NASA Astrophysics Data System (ADS)

    Gosso, Guido; Croce, Giuseppe; Matteucci, Ruggero; Peppoloni, Silvia; Piacente, Sandra; Wasowski, Janusz

    2013-04-01

    In the first decade after the Second World War Italy was rushing to recover a positive role among European countries; basic needs as road communications with European neighbours became main priorities. The necessity of a rapid connection with South-eastern France, a subject already debated between the two nations over more than 50 years, appeared then on first line; the two countries convened on a joint investment for the construction of a tunnel across the international border of Mont Blanc, along the shortest track between Courmayeur and Chamonix. The political agreements were in favour of the quickest start of the drilling operations and such obligation imposed on the Italian side an impoverishment of the project content, specially concerning geological issues. No surveys were performed on fracture systems, cataclastic zones and faults, on the few rock ridges standing above the tunnel line and outcropping through thick talus cones, moraines, ice tongues and their related ice plateaus. Metasediments, migmatites and poorly foliated granites were to be drilled. Three Italian academics were allowed by the drilling company to track the working progress and collect rocks for comparison with other Alpine types; they mapped the lithology and the fault zonesall along the freshly excavated tunnel; the results of such survey appeared after the end of works. Geologists from Florence University published the surface granite faulting pattern 20 years after the road tunnel became operative. Such geological cares could have located the risky zones in time for the tunnel project, mitigating the catastrophic effects of sudden drainage of subglacial water from the Valle Blanche ice plateau (Ghiacciaio del Gigante) at progression 3800m, that caused dramatic accidents and affected negatively the economy of the drilling. Also the wallrock temperature drops, measured during the drill, should have warned the company management on the location of dangerous fracture zones. Anxiety of national renaissance probably committed the Italian team to a fast conclusion, skipping attention from geological urgencies. But did attitudes change since then? This late episode gives us the opportunity to reflect on the necessity of making politicians seriously aware of the importance of geology when carrying out big works, to impose by law more effective policies and make interrelations between the involved professionals mandatory. Firm geoethic principles should guide choices and decisions in projects of great environmental impact.

  20. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the Olympic Medals Plaza, the new Gateway Center, and the University of Utah Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through the Park City, and Snow Basin sites of the 2002 Winter Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. See the four seasons of the Wasatch Front as observed by Landsat 7 at 15m resolution and watch the trees turn color in the Fall, snow come and go in the mountains and the reservoirs freeze and melt. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies Including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers Of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software. tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vertexes and currents in the global oceans that bring up the nutrients to feed tin) algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and biomass burning of the Earth at night observed by the "night-vision" DMSP military satellite. The demonstration is interactively driven by a SGI Octane Graphics Supercomputer with two CPUs, 4 Gigabytes of RAM and 0.5 Terabyte of disk using two projectors across a super sized panoramic 48 foot screen. In addition new HDTV technology will be demonstrated from a portable computer server.

  1. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2001-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the Olympic Medals Plaza, the new Gateway Center, and the University of Utah Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through the Park City, and Snow Basin sites of the 2002 Winter Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. See the four seasons of the Wasatch Front as observed by Landsat 7 at 15m resolution and watch the trees turn color in the Fall, snow come and go in the mountains and the reservoirs freeze and melt. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP military satellite. The demonstration is interactively driven by a SGI Octane Graphics Supercomputer with two CPUs, 4 Gigabytes of RAM and 0.5 Terabyte of disk using two projectors across a super sized panoramic 48 foot screen. In addition new HDTV technology will be demonstrated from a portable computer server.

  2. Electronic-Theater 2001: Visions of Our Planet's Atmosphere, Land and Oceans

    NASA Technical Reports Server (NTRS)

    Hasler, Authur; Starr, David OC. (Technical Monitor)

    2001-01-01

    The NASA/NOAA/AMS Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Wisconsin, Madison and the Monona Terrace Center. Drop in on the Kennedy Space Center and Park City Utah, site of the 2002 Olympics using I m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s pioneered by UW. Scientists and see them contrasted with the latest US and International global satellite weather movies including hurricanes & tornadoes. See the latest spectacular images from NASA/NOAA remote sensing missions like Terra GOES, TRMM, SeaWiFS, Landsat 7 that are visualized & explained. See how High Definition Television (HDTV) is revolutionizing the way we communicate science in cooperation with the American Museum of Natural History in NYC. See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on Newsweek, TIME, National Geographic, Popular Science covers & National & International Network TV. New visualization tools allow us to roam & zoom through massive global images eg Landsat tours of the US, Africa, & New Zealand showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See vortices and currents in the global oceans that bring up the nutrients to feed tiny plankton and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nina/La Nina climate changes. The demonstration is interactively driven by a SGI Onyx 11 Graphics Supercomputer with four CPUs, 8 Gigabytes of RAM and Terabyte of disk. With five projectors on a giant IMAX sized 18 x 72 ft screen. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "nightvision" DMSP military satellite.

  3. Lymnaea palustris and Lymnaea fuscus are potential but uncommon intermediate hosts of Fasciola hepatica in Sweden

    PubMed Central

    2013-01-01

    Background Lymnaea palustris and L. fuscus are members of the European stagnicolines (Gastropoda: Lymnaeidae). The role of stagnicolines in transmission of Fasciola hepatica has been often proposed. To assess the possible relationship between these two stagnicolines and F. hepatica in Sweden, field monitoring in parallel with experimental infections of L. palustris and L. fuscus were conducted. Methods Stagnicoline snails were collected and identified on pastures grazed by either sheep or cattle on four farms suffering from fasciolosis in Sweden during 20112012. Field-collected L. palustris and L. fuscus were examined for F. hepatica DNA by PCR. In the laboratory, different age groups of L. palustris, L. fuscus and G. truncatula were each exposed to two F. hepatica miracidia and main infection characteristics were obtained. Results One field-collected L. palustris (out of n?=?668) contained F. hepatica as determined by PCR. On the other hand, stagnicolines artificially exposed to F. hepatica miracidia resulted in successful infection with fully differentiated cercariae, but only in juvenile snails (size, 12mm at exposure) and with a prevalence of 51% and 13% in L. palustris and L. fuscus, respectively. In contrast, 90% of juvenile (size, 12mm) and 92% of preadult G. truncatula (size, ? 2-4mm), respectively, were successfully infected. Delayed, reduced and/or no spontaneous cercarial shedding was observed in the two stagnicolines when compared to G. truncatula. However, at snail dissection most cercariae from L. fuscus and L. palustris were able to encyst similarly to those from G. truncatula. Conclusion Both L. fuscus and L. palustris can sustain larval development of F. hepatica but with an apparent level of age resistance. The finding of a single F. hepatica positive specimen of L. palustris, together with infection characteristics from the experimental infection, suggest that L. palustris is a more suitable snail vector of F. hepatica than L. fuscus. The reduced growth observed in both stagnicolines was contrary to the parasitic gigantism theory. Overall, it seems that the epidemiological role of L. palustris in transmission of F. hepatica in Sweden is likely to be much lower than for G. truncatula. PMID:23985077

  4. Attitude Determination and Control Systems

    NASA Technical Reports Server (NTRS)

    Starin, Scott R.; Eterno, John

    2011-01-01

    In the year 1900, Galveston, Texas, was a bustling community of approximately 40,000 people. The former capital of the Republic of Texas remained a trade center for the state and was one of the largest cotton ports in the United States. On September 8 of that year, however, a powerful hurricane struck Galveston island, tearing the Weather Bureau wind gauge away as the winds exceeded 100 mph and bringing a storm surge that flooded the entire city. The worst natural disaster in United States history even today the hurricane caused the deaths of between 6000 and 8000 people. Critical in the events that led to such a terrible loss of life was the lack of precise knowledge of the strength of the storm before it hit. In 2008, Hurricane Ike, the third costliest hurricane ever to hit the United States coast, traveled through the Gulf of Mexico. Ike was gigantic, and the devastation in its path included the Turk and Caicos Islands, Haiti, and huge swaths of the coast of the Gulf of Mexico. Once again, Galveston, now a city of nearly 60,000, took the direct hit as Ike came ashore. Almost 200 people in the Caribbean and the United States lost their lives; a tragedy to be sure, but far less deadly than the 1900 storm. This time, people were prepared, having received excellent warning from the GOES satellite network. The Geostationary Operational Environmental Satellites have been a continuous monitor of the world's weather since 1975, and they have since been joined by other Earth-observing satellites. This weather surveillance to which so many now owe their lives is possible in part because of the ability to point accurately and steadily at the Earth below. The importance of accurately pointing spacecraft to our daily lives is pervasive, yet somehow escapes the notice of most people. But the example of the lives saved from Hurricane Ike as compared to the 1900 storm is something no one should ignore. In this section, we will summarize the processes and technologies used in designing and operating spacecraft pointing (i.e. attitude) systems.

  5. Petrogenesis of the Devonian High-Mg rock association and its tectonic implication for the Chinese Altai orogenic belt, NW China

    NASA Astrophysics Data System (ADS)

    He, Y.

    2014-12-01

    The Chinese Altai is a key region to decipher the accretionary history of the gigantic CAOB, one of the largest accretionary orogenic belts on the earth. However, its Paleozoic tectonothermal events and tectonic implications remain debated. In this study, a suite of igneous rocks, including high Mg dacite of the Kangbutiebao Formation and the associated gneissic granite, have been studied for their petrogenesis and tectonic implication. The high Mg dacite is dated at 4002Ma, which broadly resembles the emplacement age of the high Mg gneissic granite of 4069Ma, possibly suggesting that they were generated in a common tectono-magmatic event. Both rocks have zircon inheritances of ~500 Ma, which is consistent with the age of predominant zircon population for in the widespread Habahe sequence, indicating that their precursor magmas were probably mainly derived from the Habahe sediments. The high-Mg rock association has similar REE and trace element patterns to those of the Habahe sediments and they plot close to the field of the Habahe sediments in Th/Ta versus La/Ta diagram. They have high A/CNK ratios (1.33-2.05), supporting their source was sedimentary rocks. In Ba/Th versus (La/Sm)N diagram, these rocks are characterized by high La/Sm ratios which suggests a greater contribution of sediments rather than altered oceanic crust in the magma generation. However, the high Mg# values (~51) of the studied rocks argue against derivation purely from remelting of Habahe sediments. In order to explain the high Mg# values (~51) of these rocks, the participation of mantle-derived melt into the precursor magma is considered. Zircons from this rock association mostly have ?Hf(t) values from +0.85 to +9.71, supporting the involvement of juvenile materials in the magma generation. Samples from the high Mg rock association fall in the same field as the sanukitoids in TiO2 versus Mg# and Sr/Y versus Y diagrams, plot in the fractional crystallization trend of differentiated sanukitoids in Harker diagram. Similar to the sanukitoids in the Setouchi area, our high Mg rock association also involved melting of subducted sediments in a hot subduction regime. Combined with previous work, a ridge subduction regime is used to interpret the early Devonian tectonic evolution of the Chinese Altai.

  6. Climate-dependent evolution of Antarctic ectotherms: An integrative analysis

    NASA Astrophysics Data System (ADS)

    Prtner, Hans O.

    2006-04-01

    The paper explores the climate-dependent evolution of marine Antarctic fauna and tries to identify key mechanisms involved as well as the driving forces that have caused the physiological and life history characteristics observed today. In an integrative approach it uses the recent concept of oxygen and capacity limited thermal tolerance to identify potential links between molecular, cellular, whole-organism, and ecological characteristics of marine animal life in the Antarctic. As a generalized pattern, minimization of baseline energy costs, for the sake of maximized growth in the cold, appears as one over-arching principle shaping the evolution and functioning of Antarctic marine ectotherms. This conclusion is supported by recent comparisons with (sub-) Arctic ectotherms, where elevated levels of energy turnover result at unstable, including cold temperatures, and are related to wide windows of thermal tolerance and associated metabolic features. At biochemical levels, metabolic regulation at low temperatures in general, is supported by the cold compensation of enzyme kinetic parameters like substrate affinities and turnover numbers, through minute structural modifications of the enzyme molecule. These involve a shift in protein folding, sometimes supported by the replacement of individual amino acids. The hypothesis is developed that efficient metabolic regulation at low rates in Antarctic marine stenotherms occurs through high mitochondrial densities at low capacities and possibly enhanced levels of Arrhenius activation energies or activation enthalpies. This contrasts the more costly patterns of metabolic regulation at elevated rates in cold-adapted eurytherms. Energy savings in Antarctic ectotherms, largely exemplified in fish, typically involve low-cost, diffusive oxygen distribution due to high density of lipid membranes, loss of haemoglobin, myoglobin and the heat shock response, reduced anaerobic capacity, large myocytes with low ion exchange activities, and the use of lipid body stores for neutral buoyancy. Important trade-offs result from obligatory energy savings in the permanent cold: low metabolic rates support cold-compensated growth but imply narrow windows of thermal tolerance and reduced scopes for activity. The degree of thermal specialization is not uniformly defined by cold temperature but varies with life style characteristics and activity levels and associated aerobic scope. Trade-offs for the sake of cold compensated growth parallel reduced capacities for exercise performance, exacerbated by the effect of high haemolymph magnesium levels in crustaceans and, possibly, other invertebrates. High magnesium levels likely exclude the group of reptant decapod crustaceans from Antarctic waters below 0 C. The hypothesis is developed that energy savings imposed by the permanent cold bear specific life history consequences. Due to effects of allometry, energy savings are exacerbated at small body size, favouring passive lecithotrophic larvae. At all stages of life history, reduced energy turnover for the sake of growth causes delays and low rates in other higher functions, with the result of late maturity, fecundity and offspring release, as well as extended development. As a consequence, extended life spans evolved due to life history requirements. At the same time, polar gigantism is enabled by a combination of elevated oxygen levels in cold waters, of reduced metabolism and of extended periods of growth at slow developmental rates.

  7. Significance of large Neptune-crossing objects for terrestrial catastrophism

    NASA Astrophysics Data System (ADS)

    Steel, D.

    2014-07-01

    Over the past few decades a substantial number of objects have been discovered on orbits beyond Neptune (i.e. transneptunian objects, in various sub-classes), crossing Neptune's orbit (here: the Neptune-crossers of interest), and also others crossing the orbits of any or all of the jovian planets (i.e. Centaurs). These range in size from tens of kilometres across to hundreds of kilometres and more. Although formally classified as minor planets/asteroids, plus a few dwarf planets, the physical reality of these objects is that they are giant comets. That is, they seem to be composed largely of ices and if they were to enter the inner solar system then they would demonstrate the commonly-observed behaviour of comets such as outgassing, and the formation of ion and dust tails. Commonly-observed cometary behaviour, however, also includes fragmentation events and sometimes complete disintegration for no apparent cause (such as tidal disruption or thermal stresses). One might therefore wonder what the implications would be for life on Earth and terrestrial catastrophism if and when one of these objects, say 100 to 500 kilometres in size, dropped into a short-period orbit with perihelion distance (q) less than 1 au; or even q 5 au, given what Jupiter's gravity might do to it. How often might such events occur? One way to address that question would be to conduct numerical integrations of suitable test orbits and identify how often small-q orbits result, but this comes up against the problem of identifying very-infrequent events (with annual probabilities per object perhaps of order 10^{-12}-10^{-10}. For example, Emel'yanenko et al. [1] recently followed test orbits for approximately 5 10^{14} particle-years (8,925 objects with 200 clones of each, for 300 Myr) but because these were selected on the basis of initial values of q only below 36 (rather than 30) au many were not immediately Neptune-crossers; however, many test particles did eventually migrate into small-q orbits, including falling into the Sun. Instead of the demanding computational requirements of numerical integrations I have instead employed a statistical technique which involves: (i) The probability of some test orbit encountering a perturbing planet (Neptune, here); and (ii) The relative probabilities of new orbital elements (in particular q<1 au or q<5 au) resulting from such encounters. This technique I introduced in a paper presented at ACM III in Uppsala in 1989 [2] but I have not used it much in the quarter-century since then. I have presented elsewhere [3] some initial results from running this technique on a handful of known Neptune-crossing orbits, the results justifying the probabilities of order 10^{-12}-10^{-10} per annum that I mentioned above. Here I extend the range of computations and the variety of test orbits sampled in order to try to build a picture of how often the inner solar system might be subject to an incursion by a gigantic fragmenting comet, with obvious repercussions for all the terrestrial planets but especially for the evolution of life on Earth.

  8. Chandra Detects Halo Of Hot Gas Around Milky Way-Like Galaxy

    NASA Astrophysics Data System (ADS)

    2001-07-01

    The first unambiguous evidence for a giant halo of hot gas around a nearby, spiral galaxy much like our own Milky Way was found by astronomers using NASA's Chandra X-ray Observatory. This discovery may lead to a better understanding of our own Galaxy, as well the structure and evolution of galaxies in general. A team of astronomers, led by Professor Daniel Wang of the University of Massachusetts, Amherst, observed NGC 4631, a spiral galaxy approximately 25 million light years from Earth with both Chandra and NASA's Hubble Space Telescope. While previous X-ray satellites have detected extended X-ray emission from this and other spiral galaxies, because of Chandra's exceptional resolution this is the first time that astronomers were able to separate the individual X-ray sources from the diffuse halo. Chandra found the diffuse halo of X-ray gas to be radiating at a temperature of almost 3 million degrees and extending some 25,000 light years from the galactic plane. "Scientists have debated for over 40 years whether the Milky Way has an extended corona, or halo, of hot gas," said Wang, lead author of the paper which appeared this month in The Astrophysical Journal Letters. "Of course since we are within the Milky Way, we can't get outside and take a picture. However, by studying similar galaxies like NGC 4631, we can get an idea of what's going on within our own Galaxy." The Chandra image reveals a halo of hot gas that extends for approximately 25,000 light years above the disk of the galaxy. One important feature of the X-ray emission from NGC 4631 is that it closely resembles the overall size and shape seen in the radio emission from the galaxy. This indicates that there may be a close connection between the outflows of hot gas, seen in X-rays, and the galaxy's magnetic field, revealed by radio emission. The Hubble image of NGC 4631 shows filamentary, loop-like structures enclosing enhanced X-ray-emitting gas and emanating from regions of recent star formation in the galaxy's disk. These data clearly show the hot gas is heated by clusters of massive stars and is now expanding into the halo of the galaxy. NGC 4631 X-ray: NASA/CXC/UMass/D.Wang et al. UV: NASA/GSFC/UIT "What we see in NGC 4631 can be thought of as the bursting flames of a gigantic cosmic camp fire," said Wang. "Using Chandra and Hubble together, we really get a complete story of what is happening in this galaxy." NGC 4631 is a galaxy that has high amounts of star formation, possibly triggered by interaction with neighboring galaxies. Such star formation might have created the conditions necessary to heat the gas seen by Chandra, as vast amounts of energy are released from supernovas and massive stars in star-forming regions - enough to lift the gas out of the plane of the galaxy. These new results provide important clues about the cycling of energy and mass in a galaxy like our own Milky Way and about the evolutionary history of galaxies, which are thought to be more active in star formation in the past than at the present. Other members of the research team include: Stefan Immler, University of Massachusetts; Rene Walterbos, New Mexico State University; James Lauroesch, Northwestern University, Evanston, IL, and Dieter Breitschwerdt, Max Plank Institute, Germany. Chandra observed NGC 4631 with its Advanced CCD Imaging Spectrometer (ACIS) instrument, which was developed for NASA by Pennsylvania State University, University Park, and Massachusetts Institute of Technology, Cambridge. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program, and TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.

  9. Increases in seismicity rate in the Tokyo Metropolitan area after the 2011 Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Ishibe, T.; Satake, K.; Sakai, S.; Shimazaki, K.; Tsuruoka, H.; Nakagawa, S.; Hirata, N.

    2013-12-01

    Abrupt increases in seismicity rate have been observed in the Kanto region, where the Tokyo Metropolitan area is located, after the 2011 off the Pacific coast of Tohoku earthquake (M9.0) on March 11, 2011. They are well explained by the static increases in the Coulomb Failure Function (?CFF) imparted by the gigantic thrusting while some other possible factors (e.g., dynamic stress changes, excess of fluid dehydration, post-seismic slip) may also contribute the rate changes. Because of various types of earthquakes with different focal mechanisms occur in the Kanto region, the receiver faults for the calculation of ?CFF were assumed to be two nodal planes of small earthquakes before and after the Tohoku earthquake. The regions where seismicity rate increased after the Tohoku earthquake well correlate with concentration on positive ?CFF (i.e., southwestern Ibaraki and northern Chiba prefectures where intermediate-depth earthquakes occur, and in the shallow crust of western Kanagawa, eastern Shizuoka, and southeastern Yamanashi including the Izu and Hakone regions). The seismicity rate has increased since March 11, 2011 with respect to the Epidemic Type Aftershock Sequence (ETAS) model (Ogata, 1988), suggesting that the rate increase was due to the stress increase by the Tohoku earthquake. Furthermore, the z-values immediately after the Tohoku earthquake show the minimum values during the recent 10 years, indicating significant increases in seismicity rate. At intermediate depth, abrupt increases in thrust faulting earthquakes are well consistent with the Coulomb stress increase. At shallow depth, the earthquakes with the T-axes of roughly NE-SW were activated probably due to the E-W extension of the overriding continental plate, and this is also well explained by the Coulomb stress increase. However, the activated seismicity in the Izu and Hakone regions rapidly decayed following the Omori-Utsu formula, while the increased rate of seismicity in the southwestern Ibaraki and northern Chiba prefectures is still continuing. The ?CFF values for the earthquakes after March 2011 show more positive values than those before March 2011, supporting a triggering hypothesis that the 2011 Tohoku earthquake triggered the seismicity changes in the Kanto region. Dynamic stress changes due to the passage of seismic waves would also contribute the rate changes. Indeed, many remotely-triggered local events, whose occurrence times are well correlated with the arrival times of impulsive P-wave or large amplitudes of Rayleigh or Love waves, were identified from densely distributed seismograms in Japanese islands (e.g., Yukutake et al., 2011; Miyazawa, 2012). Indirectly triggered earthquakes also contribute because stress changes from neighboring indirect aftershocks could be comparable with or larger than those from a distant mainshock. Post-seismic slip and viscoelastic effects will increase the importance of earthquake triggering.

  10. Prospects of gold mineralization in the Gilgit-Baltistan Province of Pakistan

    NASA Astrophysics Data System (ADS)

    Shah, M. T.; Khan, S. D.; Tahirkheli, T.; Ahmad, L.; Miandad, S.; Rehman, A. U.; Ali, L.

    2012-12-01

    Gilgit-Baltistan province is the northern most province of Pakistan having its eastern, northern and western boarders with India, China and Afghanistan respectively. The geology of this province is unique as it has the spectacular tectonic entities of Asiatic plate (AP), Indian plate (IP) and the Kohistan-Ladakh arc (KLA). The Northern Suture Zone (NSZ) or Main Karakoram Thrust (MKT) separate the KLA from AP in the north while the Maim Mantle Thrust (MMT) separate the KLA from IP in the south. These different tectonic events have generated various types of igneous and metamorphic rocks in the form of gigantic mountain chains in the region. Considering the metallogenic provinces related to such types of tectonic environments world over, it can be suggested that the Gigit-Baltistan province may have the potential for the occurrence of economic mineral deposits. The present study is the follow-up of the previous studies for exploration of gold and base metals conducted by the Austrominerals and the Pakistan Mineral Development Corporation (PMDC) in the region. On the basis of PMDC extensive stream sediments geochemical survey of the province and delineated number of anomalous catchment areas for gold mineralization. In order to find the source bed-rock of gold, we have identified various alteration zones in these catchment areas by applying Remote sensing techniques by using both multispectral (LANDSAT, ASTER and Geoeye) and hyperspectral (Hyperion) data. Most of the alteration zones were found in steep high altitude inaccessible terrains. During this study, few of the accessible alteration zones in Golo Das, Bagrot valley, Shigri Bala, Machulu and Ranthak areas were selected for geological filed work and collection of proper samples from the alteration zones and host rocks for the identification of possible gold mineralization. In all these localities, the alteration zones are present along shear zones where the sulfide mineralization commonly occurs in the form of mainly pyrite and chalcopyrite with subordinate amount of bornite and tetrahedrite. Surface leaching of these phases to malachite, azurite and limonite is common. Quartz veining, silicification, carbonization and at places brecciation are the common features of these alteration zones. The concentrations of gold were found in the range of 3ppb to 112ppb, <5- 95ppb, 1ppb to 545ppb, 1ppb to 385 and 1ppb to 318ppb in the alteration zones of Golo Das, Bagrot valley, Shigri Bala, Machulu and Ranthak areas respectively. The barren rock samples have generally <5ppb gold. This is indicative of the multi-times enrichment of gold in the alteration zones. The sulfide mineralization along with gold in the alteration zones could be attributed to the hydrothermal/epithermal activity involving meteoric, igneous and or metamorphic fluid individually or mixture of these. The occurrence of dioritic intrusions (igneous fluid source) and the transitional dilated zones (metamorphic fluid source) on the major reactivated thrust fault (i.e., NSZ) in the vicinity of these alteration zones strengthen these observations. However, isotopic studies are underway to solve this problem. This study suggests that the alteration zones in the studied areas have the potential to be explored in detail for possible economical gold mineralization.

  11. Studies of Novel Quantum Phenomena in Ruthenates

    SciTech Connect

    Mao, Zhiqiang

    2011-04-08

    Strongly correlated oxides have been the subject of intense study in contemporary condensed matter physics, and perovskite ruthenates (Sr,Ca)n+1RunO3n+1 have become a new focus in this field. One of important characteristics of ruthenates is that both lattice and orbital degrees of freedom are active and are strongly coupled to charge and spin degrees of freedom. Such a complex interplay of multiple degrees of freedom causes the properties of ruthenates to exhibit a gigantic response to external stimuli under certain circumstances. Magnetic field, pressure, and chemical composition all have been demonstrated to be effective in inducing electronic/magnetic phase transitions in ruthenates. Therefore, ruthenates are ideal candidates for searching for novel quantum phenomena through controlling external parameters. The objective of this project is to search for novel quantum phenomena in ruthenate materials using high-quality single crystals grown by the floating-zone technique, and investigate the underlying physics. The following summarizes our accomplishments. We have focused on trilayered Sr4Ru3O10 and bilayered (Ca1-xSrx)3Ru2O7. We have succeeded in growing high-quality single crystals of these materials using the floating-zone technique and performed systematic studies on their electronic and magnetic properties through a variety of measurements, including resistivity, Hall coefficient, angle-resolved magnetoresistivity, Hall probe microscopy, and specific heat. We have also studied microscopic magnetic properties for some of these materials using neutron scattering in collaboration with Los Alamos National Laboratory. We have observed a number of unusual exotic quantum phenomena through these studies, such as an orbital selective metamagnetic transition, bulk spin valve effect, and a heavy-mass nearly ferromagnetic state with a surprisingly large Wilson ratio. Our work has also revealed underlying physics of these exotic phenomena. Exotic phenomena of correlated electron has been among central topics of contempary condensed matter physics. Ultrfast phase transitions accompanied by switching of conductivity or magnetization in stronly correlated materials are believed to be promising in developing next generation of transistors. Our work on layered ruthenates has remarkably advanced our understanding of how the exotic phenomena of correlated electrons is governed by the complex interplay between charge, spin, lattice and orbital degrees of freedom. In addition to studies on ruthenates, we have also expanded our research to the emerging field of Fe-based superconductors, focusing on the iron chalcogenide Fe1+y(Te1-xSex) superconductor system. We first studied the superconductivity of this alloy system following the discovery of superconductivity in FeSe using polycrystalline samples. Later, we successfuly grew high-quality single crystals of these materials. Using these single crystals, we have determined the magnetic structure of the parent compound Fe1+yTe, observed spin resonance of superconducting state in optimally doped samples, and established a phase diagram. Our work has produced an important impact in this burgeoning field. The PI presented an invited talk on this topic at APS March meeting in 2010. We have published 19 papers in these two areas (one in Nature materials, five in Physical Review Letters, and nine in Physical Review B) and submitted two (see the list of publications attached below).

  12. Alkaline lavas from southern Mendoza, Argentina, extend the Patagonian DUPAL mantle field to the north

    NASA Astrophysics Data System (ADS)

    Soager, N.; Holm, P. M.; Llambias, E.

    2010-12-01

    The lavas sampled around Ro Colorado ~37S at the border of Mendoza and Neuqun provinces, Argentina, define an OIB-like end-member composition for the Pleistocene and Holocene activity in the Payn Matr volcanic field. Although positioned in the far back-arc of the Andes, only a few lavas show signs of involvement of slab fluids or crustal contamination such as relatively high LILEs relative to Nb. The very low La/Nb (~0.66) and Zr/Nb (~5) and high U/Pb (0.3-0.4) of the end-member composition clearly distinguish the source from normal MORB mantle, while high Ba/Nb (~10) and K/Nb (370-400) compared to FOZO and HIMU type OIBs suggest an EM type of mantle. Overall, the trace element patterns of the Ro Colorado lavas are similar to the central and north Patagonian intraplate basalts and to South Atlantic E-MORB affected by the Discovery plume and the LOMU component (le Roux et al., 2002, EPSL 203). The isotopic composition of the Ro Colorado component has a 206Pb/204Pb = 18.4, 207Pb/204Pb = 15.58, 208Pb/204Pb = 38.3, 87Sr/86Sr = 0.70353 and 143Nd/144Nd = 0.51285. This composition overlaps the central and north Patagonian intraplate basalts in Pb-isotopic space but is slightly less enriched in Sr and Nd-isotopes. It is distinctly different from the FOZO like composition of the south Patagonian intraplate basalts and the nearby Juan Fernandz plume but similar to the South Atlantic N-MORB and MORB from the southern Chile Ridge segment 4 (Sturm et al., 1999, JGR 104) described as DUPAL type. The DUPAL-MORB type isotopic composition and the plume-like trace element patterns of the Ro Colorado lavas suggest the presence of a weak plume beneath the area. The eruption of the large Payn Matr volcano and the gigantic Pleistocene flood basalts also calls for a thermal anomaly to produce these melts during a weakly compressive tectonic regime with no significant addition of slab fluids. This was supported by Burd et al. (2008, Abstr., 7th Int. Sym. And. Geo.) who recognized a plume-like conductive structure beneath Payn Matr volcano on an electrical resistivity profile across the Payn Matr volcanic field. The many Argentine and Chile Ridge EM1 basalts form part of the global DUPAL-anomaly (Hart, 1984, Nature 309) which suggests a common mode of formation of the enriched mantle sources; most likely anciently subducted components in the underlying upper mantle, either in a larger reservoir or as dispersed bodies of material. From there they can rise as small plumes or be entrained in a convecting MORB source mantle.

  13. Recent advances in sensitized mesoscopic solar cells.

    PubMed

    Grtzel, Michael

    2009-11-17

    Perhaps the largest challenge for our global society is to find ways to replace the slowly but inevitably vanishing fossil fuel supplies by renewable resources and, at the same time, avoid negative effects from the current energy system on climate, environment, and health. The quality of human life to a large degree depends upon the availability of clean energy sources. The worldwide power consumption is expected to double in the next 3 decades because of the increase in world population and the rising demand of energy in the developing countries. This implies enhanced depletion of fossil fuel reserves, leading to further aggravation of the environmental pollution. As a consequence of dwindling resources, a huge power supply gap of 14 terawatts is expected to open up by year 2050 equaling today's entire consumption, thus threatening to create a planetary emergency of gigantic dimensions. Solar energy is expected to play a crucial role as a future energy source. The sun provides about 120,000 terawatts to the earth's surface, which amounts to 6000 times the present rate of the world's energy consumption. However, capturing solar energy and converting it to electricity or chemical fuels, such as hydrogen, at low cost and using abundantly available raw materials remains a huge challenge. Chemistry is expected to make pivotal contributions to identify environmentally friendly solutions to this energy problem. One area of great promise is that of solar converters generally referred to as "organic photovoltaic cells" (OPV) that employ organic constituents for light harvesting or charge carrier transport. While this field is still in its infancy, it is receiving enormous research attention, with the number of publications growing exponentially over the past decade. The advantage of this new generation of solar cells is that they can be produced at low cost, i.e., potentially less than 1 U.S. $/peak watt. Some but not all OPV embodiments can avoid the expensive and energy-intensive high vacuum and materials purification steps that are currently employed in the fabrication of all other thin-film solar cells. Organic materials are abundantly available, so that the technology can be scaled up to the terawatt scale without running into feedstock supply problems. This gives organic-based solar cells an advantage over the two major competing thin-film photovoltaic devices, i.e., CdTe and CuIn(As)Se, which use highly toxic materials of low natural abundance. However, a drawback of the current embodiment of OPV cells is that their efficiency is significantly lower than that for single and multicrystalline silicon as well as CdTe and CuIn(As)Se cells. Also, polymer-based OPV cells are very sensitive to water and oxygen and, hence, need to be carefully sealed to avoid rapid degradation. The research discussed within the framework of this Account aims at identifying and providing solutions to the efficiency problems that the OPV field is still facing. The discussion focuses on mesoscopic solar cells, in particular, dye-sensitized solar cells (DSCs), which have been developed in our laboratory and remain the focus of our investigations. The efficiency problem is being tackled using molecular science and nanotechnology. The sensitizer constitutes the heart of the DSC, using sunlight to pump electrons from a lower to a higher energy level, generating in this fashion an electric potential difference, which can exploited to produce electric work. Currently, there is a quest for sensitizers that achieve effective harnessing of the red and near-IR part of sunlight, converting these photons to electricity better than the currently used generation of dyes. Progress in this area has been significant over the past few years, resulting in a boost in the conversion efficiency of the DSC that will be reviewed. PMID:19715294

  14. New Indivisible Planetary Science Paradigm: Consequence of Questioning Popular Paradigms

    NASA Astrophysics Data System (ADS)

    Marvin Herndon, J.

    2014-05-01

    Progress in science involves replacing less precise understanding with more precise understanding. In science and in science education one should always question popular ideas; ask "What's wrong with this picture?" Finding limitations, conflicts or circumstances that require special ad hoc consideration sometimes is the key to making important discoveries. For example, from thermodynamic considerations, I found that the 'standard model of solar system formation' leads to insufficiently massive planetary cores. That understanding led me to discover a new indivisible planetary science paradigm. Massive-core planets formed by condensing and raining-out from within giant gaseous protoplanets at high pressures and high temperatures, accumulating heterogeneously on the basis of volatility with liquid core-formation preceding mantle-formation; the interior states of oxidation resemble that of the Abee enstatite chondrite. Core-composition was established during condensation based upon the relative solubilities of elements, including uranium, in liquid iron in equilibrium with an atmosphere of solar composition at high pressures and high temperatures. Uranium settled to the central region and formed planetary nuclear fission reactors, producing heat and planetary magnetic fields. Earth's complete condensation included a ~300 Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66% of Earth's present diameter. T-Tauri eruptions, associated with the thermonuclear ignition of the Sun, stripped the gases away from the Earth and the inner planets. The T-Tauri outbursts stripped a portion of Mercury's incompletely condensed protoplanet and transported it to the region between Mars and Jupiter where it fused with in-falling oxidized condensate from the outer regions of the Solar System, forming the parent matter of ordinary chondrite meteorites, the main-Belt asteroids, and veneer for the inner planets, especially Mars. With its massive gas/ice shell removed, pressure began to build in the compressed rocky kernel of Earth and eventually the rigid crust began to crack. The major energy source for planetary decompression and for heat emplacement at the base of the crust is the stored energy of protoplanetary compression. In response to decompression-driven volume increases, cracks form to increase surface area and fold-mountain ranges form to accommodate changes in curvature. One of the most profound mysteries of modern planetary science is this: As the terrestrial planets are more-or-less of common chondritic composition, how does one account for the marked differences in their surface dynamics? Differences among the inner planets are principally due to the degree of compression experienced. Planetocentric georeactor nuclear fission, responsible for magnetic field generation and concomitant heat production, is applicable to compressed and non-compressed planets and large moons. The internal composition of Mercury is calculated based upon an analogy with the deep-Earth mass ratio relationships. The origin and implication of Mercurian hydrogen geysers is described. Besides Earth, only Venus appears to have sustained protoplanetary compression; the degree of which might eventually be estimated from understanding Venetian surface geology. A basis is provided for understanding that Mars essentially lacks a 'geothermal gradient' which implies potentially greater subsurface water reservoir capacity than previously expected. Resources at NuclearPlanet.com .

  15. Triggering a Wet Climate on Mars: The Role of Outflow Channels in Martian Water Cycles

    NASA Astrophysics Data System (ADS)

    Santiago, D.; Asphaug, E. I.; Colaprete, A.

    2011-12-01

    The triggering of a robust water cycle on Mars has been hypothesized to be caused by gigantic flooding events evidenced by outflow channels. Here we use the Ames Mars General Circulation Model (MGCM) to study how these presumably abrupt eruptions of water (Carr,1996) affected the climate of Mars. We model where the water ultimately went as part of a transient hydrologic cycle. Chryse Planitia, east of Tharsis, has evidence for multiple water outflow channels. One of the largest channels is Ares Valles, which was carved by floods with estimated water volumes of order 10^5 km^2 (Andrews-Hanna, 2007 & Carr, 1996). Outflow discharge rate estimates range from 10^6 to 10^7 m^3/seconds or greater (Andrews-Hanna & Phillips, 2007, Harrison & Grimm, 2008). Studies suggest that outflow channels formed with smaller, successive floods instead of a single large flood (Wilson, et al.,2004). Warner et al. (2009) suggest up to six outflow events for the formation of Ares Valles, while estimates for another large outflow, Kasei Valles, might have been flooded by over two thousand floods with a total water volume of 5.5 x 10^5 km^3 (Harrison & Grimm, 2008). By adding water to the surface of Mars at the given outflow rate, as an expanding one-layer lake, we are able to study quantitatively how these outflow events influenced Mars climate, particularly the hydrologic cycle. In particular: Could sudden introductions of large amounts of water on the Martian surface lead to a new equilibrated water cycle? Can we tie certain fluvial surface features to transient or sustained water cycles? What are the roles of water vapor and water ice clouds to sudden changes in the water cycle on Mars? How are radiative feedbacks involved with this? What is the ultimate fate of the outflow water? This work uses the NASA Ames MGCM version 2.1 and other schemes that are part of the NASA Ames MGCM suite of tools. Various versions of the MGCM developed at Ames have been used extensively to examine dust and volatile distributions on Mars (e.g., Kahre et al., 2006, 2008). The MGCM 2.1 currently has a well-developed water ice cloud formation scheme (Montmessin et al., 2002, 2004a), which includes calculation of cloud particle concentrations, nucleation, growth, and gravitational sedimentation. For examining the effect of a large water outflow on the climate of Mars, we include water tracers, with an advanced cloud particle scheme Preliminary results suggest that water may have been transported globally for years post-outflow. Post-outflow water cloud formation increases dramatically, with water ice clouds and water vapor potentially transporting water globally. The global mass of water vapor and of water ice clouds increases substantially, with the post-outflow patterns settling into annual cycles, with increasing water entering the atmosphere from the surface over time. Future work will examine the radiative effects of the water vapor and water ice clouds, and the longer-term persistence of a new hydrological or climate regime Detailed comparisons of post-outflow precipitation locations with fluvial features on Mars will be done.

  16. Tanque Loma, a new late-Pleistocene megafaunal tar seep locality from southwest Ecuador

    NASA Astrophysics Data System (ADS)

    Lindsey, Emily L.; Lopez R., Eric X.

    2015-01-01

    Fossil deposits in the petroleum-rich sediments of the Santa Elena Peninsula in southwestern Ecuador contain some of the largest and best-preserved assemblages of Pleistocene megafaunal remains known from the neotropics, and thus represent an opportunity to greatly expand our knowledge of Pleistocene paleoecology and the extinction of Quaternary megafauna in this region. This paper reports data from excavations at Tanque Loma, a late-Pleistocene locality on the Santa Elena Peninsula that preserves a dense assemblage of megafaunal remains in hydrocarbon-saturated sediments along with microfaunal and paleobotanical material. The megafauna bones are concentrated in and just above a ?0.5 m thick asphaltic layer, but occur sparsely and with poorer preservation up to 1 m above this deposit. Several meters of presumed-Holocene sediments overlying the megafauna-bearing strata are rich in bones of microvertebrates including birds, squamates, and rodents. These are interpreted as raptor assemblages. While over 1000 megafaunal bones have been identified from the Pleistocene strata at Tanque Loma, more than 85% of these remains pertain to a single species, the giant ground sloth Eremotherium laurillardi. Only five other megafauna taxa have been identified from this site, including Glossotherium cf. tropicorum, Holmesina occidentalis, cf. Notiomastodon platensis, Equus (Amerhippus) c.f. santaeelenae, and a cervid tentatively assigned to cf. Odocoileus salinae based on body size and geography. No carnivores have yet been identified from Tanque Loma, and microvertebrate remains are extremely rare in the Pleistocene deposits, although terrestrial snail shells and fragmented remains of marine invertebrates are occasionally encountered. Accelerator Mass Spectrometry radiocarbon dates on Eremotherium and cf. Notiomaston bones from within and just above the asphaltic layer yielded dates of ?17,000 - 23,500 radiocarbon years BP. Taken together, the taxonomic composition, taphonomy, geologic context, and sedimentology of Tanque Loma suggest that this site represents a bone bed assemblage in a heavily vegetated, low-energy riparian environment with secondary infiltration of asphalt that helped to preserve the bones. The predominance of Eremotherium fossils at this site indicate that it may have been an area where these animals congregated, suggesting possible gregarious behavior in this taxon. The radiocarbon dates so far obtained on extinct taxa at Tanque Loma are consistent with a model positing earlier extinctions of megafauna in tropical South America than of related taxa further south on the continent, although this pattern may be an artifact of low sampling in the region. Aunque ms de 1.000 huesos de megafauna han sido identificados en los estratos del Pleistoceno en Tanque Loma, ms del 85% de esos mismos pertenecen a una sola especie, el perezoso gigante Eremotherium laurillardi. Sin embargo, otros cinco taxones de megafauna han sido recuperados de este sitio, los cuales son: Glossotherium cf. G. tropicorum, Holmesina occidentalis, cf. Notiomastodon platensis, Equus (Amerhippus) c.f. santaelenae y un crvido identificado tentativamente en base a tamao y geografa como cf. Odocoileus salinae. Ningn carnvoro ha sido identificado an en Tanque Loma, y los restos de microvertebrados son muy raros en los estratos del Pleistoceno, aunque las conchas de caracol terrestre y los restos fragmentados de invertebrados marinos son encontrados ocasionalmente dentro de esas capas. Los fechados de radiocarbono por espectrmetro de acelerador de masas (AMS) en huesos de Eremotherium y cf. Notiomastodon de la capa de asfalto y por encima de esta resultaron en ?17,000-23,500 aos radiocarbnicos AP. En conjunto, la tafonoma, la composicin taxonmica, el contexto geolgico, y la sedimentolga del sitio Tanque Loma surgieren que esta localidad representa un yacimiento depositado en un ambiente ribereo con bajo flujo y vegetacin densa, con infiltraciones secundarias de asfalto lo que ayud a preservar los huesos. El predomin

  17. Study of the early signal perturbations due to GJ and Elves using the LWPC code

    NASA Astrophysics Data System (ADS)

    Nait Amor, Samir; Ghalila, Hassen; Bouderba, Yasmina

    2015-04-01

    Early events are a Very Low Frequencies (VLF) signal perturbations recorded during a lightning activity. The properties of these signal perturbations and their association to the lightning peak current and/or Transient Luminous Events (TLEs) were widely studied. In a recently analysis a new early signal perturbations whose recovery time persists for several minutes were discovered. The underlying cause of these events is still unclear. In a recently published work, these events were attributed to the lightning peak current and the type of associated TLE. In others, and newly published papers, analyzes were done where all kind of early events were considered. Statistical results showed that the occurrence of long recovery events is independent of the lightning current amplitude and/or TLEs type. To understand which is the main cause of these events, we analyzed two types of early signal perturbations: One was a typical event (~200s time duration) in association with a Gigantic Jet and the second was a long recovery event in association with an elve recorded on December 12 2009 during the EuroSprite campaign. In addition to the VLF signal analysis, we used the Long Wave Propagation Capability (LWPC) code to simulate the unperturbed and perturbed signal parameters (amplitude and phase), to determine the signal modes attenuation coefficient and then to infer the electron density increases in the disturbed region. The results showed that the reference height was reduced from its ambient value (87km) to 66.4 km in the case of the GJ and 74.3 km for the elve. These reference heights decreases affected the propagating signal at the disturbed region by increasing the modes attenuation coefficient. Effectively, the number of modes was reduced from 28 at ambient condition to 9 modes (in the case of GJ) and 17 (in the case of elve). This high attenuation of modes leads to the appearance of null signal perturbations positions due to the interferences. Between two null positions the signal perturbation was negative (or decreasing) and sometimes positive (or increasing). It was also observed from the LWPC code results that the perturbation amplitude was maximum when the perturbed and unperturbed signals were in phase. Thus the main reason of these observations is the modal structure of the signal at the disturbed region and the receiver location. The electron density increases reached 104 cm-3 at 85 km independently on TLE kind. By the use of the signal perturbation parameters due to the long recovery event and the LWPC code, a recovery time profile of the electron density at each height below 87 km is obtained. The first order exponential decay fit gives different recovery constants depending on the height. This is in good agreement with the atmospheric model where the loss terms rates vary with altitude.

  18. Age of the Australasian Tektite Strewn Field

    NASA Astrophysics Data System (ADS)

    Izokh, E. P.

    1993-07-01

    As Fig. 1 shows, the widespread belief that the age of the Australasian tektite strewn field (AATSF) is ~0.7 m.y. appeared to be conventional. Tektites of different fission-track ages were found within the AATSF: 0.83 m.y. [1], 3.54-4.25 m.y. [2], and ~11 m.y. [3]. The first systematic investigation of the tektites, which were collected from a single stratigraphic layer in Vietnam, revealed three statistically discrete tektite age groups: 0.4, 0.6, and 0.8 m.y. [4]. Similar tektites 0.75 m.y. and 1.1 m.y. in age are typical of the Zhamanshin impact crater, which represents an eminent part of the AATSF [5]. Fig. 1, which appears here in the hard copy, shows radiogenic dating: 1-2: AATSF; 3-4: Zhamanshin; 1,3: data with known annealing correction. Compiled after Zahringer, 1963; Fleischer and Price, 1964; Gentner et al., 1969; McDougal and Lovering, 1969; Fleischer et al., 1969; Storzer and Wagner, 1979, 1980; Watanabe et al., 1985; Virk, 1985; Shukolukov et al., 1986; Kashkarov et al, 1986, 1987; Kolesnikov et al., 1987; Storzer and Muller-Sonhius, 1986; Arakelyants et al., 1988; etc. The very young geological age of the AATSF was established in Australia, and was confirmed by the author in Vietnam and in the Zhamanshin impact crater. This well-known tektite age paradox strongly supports an extraterrestrial origin of tektites. The paradox is fatal to the currently dominating Earth- impact theory of tektite origin, and we are not surprised that there are no continued attempts to either silence or disavow its significance. As a matter of fact, the formation of the gigantic AATSF can be considered as the main reason for the abrupt catastrophic climatic global changes and mass extinction of species on the Pleistocene/Holocene boundary 10,000 years ago [5,6]. The age-paradox scope dictates that tektites have been periodically formed and accumulated somewhere on an as-yet-unknown planetary body and then delivered to the Earth. The extraterrestrial volcanic eruptions seem to be the most appropriate process of the tektite formation and launching [7]. The frequent shift of the K-Ar ages relative to the fission-track ages of tektites can be explained by the presence of an extra argon inherited from some older crystalline inclusions foreign to the tektite glass. These inclusions are most common to the Muong Nong-type layered tektites and to flanges of the button-shape australites, and can be considered as an extraterrestrial environmental dust peppering. References: [1] Storzer and Wagner (1980) Meteoritics, 15, 372. [2] Fleischer et al. (1969) EPSL, 7, 51-52. [3] Storzer and Muller-Sonhius (1986) Meteoritics, 21, 518-519. [4] Kashkarov et al. (1986) Meteoritika, 45, 105-170. [5] Izokh (1991) Soviet Geol. and Geophys., 32, 1-10. [6] Tollman and Tollmann (1992) Mitt. Osterr. Geol. Ges., 84. [7] Izokh and Le duc An (1983) Meteoritika, 42, 158-169.

  19. The Role Of Oceanic Plateau Volcanism On Climate Change: Warming And Cooling Episodes Across Early Aptian Oceanic Anoxic Event 1a

    NASA Astrophysics Data System (ADS)

    Bottini, C.; Erba, E.; Mutterlose, J.

    2011-12-01

    The early Aptian is marked by a global phenomenon of organic matter burial in oxygen-depleted oceans known as Oceanic Anoxic Event 1a (OAE 1a: ~120 Ma). Volcanism associated with the emplacement of the Ontong Java Plateau (OJP) is thought to be the main triggering mechanism for global anoxia, ocean acidification and greenhouse conditions. However, climate instability during OAE 1a is indicated by independent studies on TEX86, sporomorphs and oxygen-stable isotope but a direct connection between OJP volcanic phases and temperature variations has not been ascertained. A high-resolution integrated nannofossil-geochemical investigation of distant sections from the Tethys, the Pacific Ocean and the Boreal Realm has revealed systematic and synchronous changes. Specifically, the nannofossil Temperature Index and Os-isotope records allowed the reconstruction of a complex series of global warming and cooling events across OAE 1a and their relationships with OJP volcanism as well as weathering patterns. Two prominent volcanic phases are documented in the Os-isotope records: the first preceding OAE 1a and the second one, of major intensity, starting in the core of the negative C-isotopic anomaly. Both phases are paralleled by increased temperature, suggestive of a (super)greenhouse climate triggered by excess volcanogenic CO2. Indeed, our data indicate that the beginning of the prolonged volcanic phase during OAE 1a coincides with warmest temperatures. In the early part of OAE 1a, between the two major volcanic phases, there is a ~100 kyrs-long interval characterized by a radiogenic Os-isotope peak, suggestive of accelerated continental weathering rates, with or without volcanism cessation, following an interval of abrupt warming and preceding a cooling interlude. Arguably, warming at OAE 1a onset promoted methane hydrate dissociation (also suggested by C-isotope and biomarkers analyses), which was perhaps instrumental in triggering continental weathering. Subsequent CO2 draw down, possibly during OJP quiescence, might explain the brief cooling interlude annihilated by warmest temperatures coeval with the onset of OJP paroxysmal phase. In the second part of OAE 1a two more cooling events sandwich an interval of intermediate and fluctuating temperatures. The three cooling episodes correlate with high TOC content, suggesting that burial of organic matter acted as storage of excess CO2, thus temporarily mitigating greenhouse conditions, although under persisting OJP activity. The end of OAE 1a corresponds to the vanishing of OJP volcanism as recorded by Os-isotope. A major cooling episode decrees the conclusion of greenhouse conditions for the rest of the Aptian. Increasing data and improved chronology show that volcanism of gigantic plateaus such as OJP is qualified to cause severe global warming and also indirectly to impact temperature changes. In fact, positive and negative feedbacks vicariously governed by prolonged (and possibly pulsing) formation of oceanic plateaus may be likewise or even more influential in controlling climate variability.

  20. Solar and Drag Sail Propulsion: From Theory to Mission Implementation

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Alhorn, Dean; Boudreaux, Mark; Casas, Joe; Stetson, Doug; Young, Roy

    2014-01-01

    Solar and drag sail technology is entering the mainstream for space propulsion applications within NASA and around the world. Solar sails derive propulsion by reflecting sunlight from a large, mirror- like sail made of a lightweight, reflective material. The continuous sunlight pressure provides efficient primary propulsion, without the expenditure of propellant or any other consumable, allowing for very high V maneuvers and long-duration deep space exploration. Drag sails increase the aerodynamic drag on Low Earth Orbit (LEO) spacecraft, providing a lightweight and relatively inexpensive approach for end-of-life deorbit and reentry. Since NASA began investing in the technology in the late 1990's, significant progress has been made toward their demonstration and implementation in space. NASA's Marshall Space Flight Center (MSFC) managed the development and testing of two different 20-m solar sail systems and rigorously tested them under simulated space conditions in the Glenn Research Center's Space Power Facility at Plum Brook Station, Ohio. One of these systems, developed by L'Garde, Inc., is planned for flight in 2015. Called Sunjammer, the 38m sailcraft will unfurl in deep space and demonstrate solar sail propulsion and navigation as it flies to Earth-Sun L1. In the Flight Center (MSFC) managed the development and testing of two different 20-m solar sail systems and rigorously tested them under simulated space conditions in the Glenn Research Center's Space Power Facility at Plum Brook Station, Ohio. One of these systems, developed by L'Garde, Inc., is planned for flight in 2015. Called Sunjammer, the 38m sailcraft will unfurl in deep space and demonstrate solar sail propulsion and navigation as it flies to Earth-Sun L1. In the interim, NASA MSFC funded the NanoSail-D, a subscale drag sail system designed for small spacecraft applications. The NanoSail-D flew aboard the Fast Affordable Science and Technology SATellite (FASTSAT) in 2010, also developed by MSFC, and began its mission after it was ejected from the FASTSAT into Earth orbit, where it remained for several weeks before deorbiting as planned. NASA recently selected two small satellite missions for study as part of the Advanced Exploration Systems (AES) Program, both of which will use solar sails to enable their scientific objectives. Lunar Flashlight, managed by JPL, will search for and map volatiles in permanently shadowed Lunar craters using a solar sail as a gigantic mirror to steer sunlight into the shaded craters. The Near Earth Asteroid (NEA) Scout mission will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interests for possible future human exploration. Both are being studied for possible launch in 2017. The Planetary Society's privately funded LightSail-A and -B cubesat-class spacecraft are nearly complete and scheduled for launch in 2015 and 2016, respectively. MMA Design launched their DragNet deorbit system in November 2013, which will deploy from the STPSat-3 spacecraft as an end of life deorbit system. The University of Surrey is building a suite of cubesat class drag and solar sail systems that will be launched beginning in 2015. As the technology matures, solar sails will increasingly be used to enable science and exploration missions that are currently impossible or prohibitively expensive using traditional chemical and electric rockets. For example, the NASA Heliophysics Decadal Survey identifies no less than three such missions for possible flight before the mid-2020's. Solar and drag sail propulsion technology is no longer merely an interesting theoretical possibility; it has been demonstrated in space and is now a critical technology for science and solar system exploration.

  1. Surface Particle Detectors in Space Weather forecast

    NASA Astrophysics Data System (ADS)

    Chilingarian, Ashot

    Recently several groups report on the development of the alarm system based on the surface particle detector data. Among them are high-latitude neutron monitors network "Spaceship Earth", coordinated by the group from Bartol Research Center; Muon network coordinated by the group from Shinshu University and Athens Neutron Monitor Data Processing Center. In the presented report, based on the information content of data from particle detectors of Aragats Space Environmental Center (ASEC) we made attempt to review possibility of surface particle detectors in Space Weather forecasts. Particle monitors located at ASEC at 1000, 2000 and 3200 m altitudes (40?25 N, 44?15 E; Vertical cut-off rigidity in 2007: 7.1 GV) detect charged and neutral components of the secondary cosmic rays with different energy thresholds and various angles of incidence. ASEC monitors reliably detect the highest energy CR due to unique geographical location and large underground high energy muon detector. Forecasting of the Solar Energetic Proton (SEP) events by surface particle detectors is based on the detection of the Ground Level Enhancements (GLE). Unfortunately not all SEPs contain particles energetic enough to produce GLE, therefore, the efficiency of the warnings will not be very high. Nonetheless, we can expect that the major events, (like 1859, 1956, 1972, 1989) with high probability will generate GLEs and surface detectors can provide forewarnings on upcoming abundant SEP particles. With the exception of the event on 20 January, when due to very good magnetic connection of the flare site with earth, all relativistic particles seem to come simultaneously, the enhancements of GeV solar particles detected by surface particle detectors can alert on upcoming severe radiation storm. The alerts from middle and low latitude monitors are even more important compared to high latitude networks, because of lower probability of false alarms. If an enhancement occurs at monitors with large cutoff rigidity it indicates that spectral knee occurs at large enough energy. Enhancements in the ASEC detectors count rates indicate higher solar ion energies, and, consequently hard spectra of the GLE in progress. The triggers of the Geomagnetic Storms are huge magnetized clouds (Coronal mass ejections - CMEs), emitted by sun and traveling in the Interplanetary Space (IP). This gigantic plasma clouds with "frozen" magnetic field (Interplanetary CMEs, - ICMEs) disturb the Interplanetary Magnetic Field and "modulate "the ambient flux of the Galactic Cosmic rays (GCR). On the way to Earth (15 - 70 hours) the magnetic cloud and shock change GCR intensity and make it anisotropic. The strength of these modulation effects correlate with severity of the geomagnetic storm. Networks of the particle detectors located on Earth surface detect these modulation effects and can predict the upcoming geomagnetic storms hours before the ICME arrival at the magnetometers on ACE and SOHO space stations. We will demonstrate that simultaneously detection of the charged and neutral components of the secondary cosmic rays made by ASEC monitors enlarged possibilities of physical inference on the solar modulation effects and, therefore, enlarges possibilities of timely and reliable forecasts of dangerous consequences of radiation and geomagnetic storms.

  2. Volcanism, Impacts and Mass Extinctions: A case study of the Deccan Traps and its global effects

    NASA Astrophysics Data System (ADS)

    Keller, G.

    2012-12-01

    The nature and causes of mass extinctions in the geological past have remained topics of intense scientific debate for the past three decades. Central to this debate is the question of whether one, or several large bolide impacts, the eruption of large igneous provinces (LIP) or a combination of the two were the primary mechanisms driving the environmental changes that are universally regarded as the proximate causes for four of the five major Phanerozoic extinction events. Recent years have seen a revolution in our understanding of interplanetary environments, LIP eruptions and their environmental effects such that the simple impact-kill scenario no longer seems an adequate explanation for the Cretaceous-Tertiary boundary (KTB) or any other mass extinction. The KTB is the only mass extinction associated with both impact (Chixculub) and flood basalts (Deccan Traps) and therefore an excellent case study to evaluate the potential causes and effects. Deccan eruptions likely occurred as "pulses", with some gigantic megaflows 1500 km across India and with estimated volumes >10,000 km3 that may have erupted over very short time intervals. For comparison, the largest historical basalt eruption in 1783 in Iceland (Laki) ejected some 15 km3 of lava in about a year. A single Deccan megaflow would have been equivalent to 667 Laki. The vast amount of carbon and sulphur dioxides injected into the atmosphere from just one Deccan megaflow would have been on the same order of magnitude as those estimated for the Chicxulub impact. Deccan Traps erupted in three main phases with 6% total Deccan volume in phase-1 (base C30n), 80% in phase-2 (C29r) and 14% in phase-3 (C29n). Phase-2 and phase-3 each produced four giant megaflows leading to the KTB mass extinction and the long delayed biotic recovery, respectively. Data from infra- and intertrappean sediments of these megaflows drilled in the Krishna-Godavari Basin by India's Oil and Natural Gas Corporation reveal swift and devastating effects on marine plankton in India. A 50% drop in diversity of planktic foraminifera preceded the first megaflow, another 50% drop thereafter, leaving just 7 to 8 survivor species. No recovery occurred between the next three mega-flows and the mass extinction was complete with the last phase-2 megaflow at the KTB. All three Deccan phases can be identified globally by decreased species diversity, selective extinctions (e.g., planktic foraminifera, inoceramids, ammonoids, rudists, dinosaurs), dwarfing, blooms of disaster opportunists and rapid climate changes. Effects of Deccan phase-1 were relatively short-term; phase-2 led to the KTB extinctions and phase-3 caused the long delayed marine recovery. Although debates regarding the proximate mechanisms of the KTB mass extinction are ongoing, they are likely linked to the enormous pulsed injections of gases into the atmosphere, generating alternating episodes of cooling and warming, acid rain leading to marine calcification crises, increased weathering and terrestrial runoff leading to large nutrient influx into oceans and causing oxygen-depleted conditions hostile to marine life. The Chicxulub impact would have exacerbated an already heavily stressed environment due to Deccan volcanism.

  3. The Behemoth Has a Thick Belt

    NASA Astrophysics Data System (ADS)

    2008-05-01

    Talk about a diet! By resolving, for the first time, features of an individual star in a neighbouring galaxy, ESO's VLT has allowed astronomers to determine that it weighs almost half of what was previously thought, thereby solving the mystery of its existence. The behemoth star is found to be surrounded by a massive and thick torus of gas and dust, and is most likely experiencing unstable, violent mass loss. dusty torus around WOH G64 ESO PR Photo 15/08 The Torus around WOH G64 Artist's Impression WOH G64 is a red supergiant star almost 2 000 times as large as our Sun and is located 163 000 light-years away in the Large Magellanic Cloud, one of the Milky Way's satellite galaxies. "Previous estimates gave an initial mass of 40 times the mass of the Sun to WOH G64. But this was a real problem as it was way too cold, compared to what theoretical models predict for such a massive star. Its existence couldn't be explained," says Keiichi Ohnaka, who led the work on this object. New observations, made with ESO's Very Large Telescope Interferometer, conclude that the gas and dust around the star is arranged in a thick ring, rather than a spherical shell, and the star is thus less hidden than had been assumed. This implies that the object is in fact half as luminous as previously thought, and thus, less massive. The astronomers infer that the star started its life with a mass of 25 solar masses. For such a star, the observed temperature is closer to what one would expect. "Still, the characteristics of the star mean that it may be experiencing a very unstable phase accompanied by heavy mass loss," says co-author Markus Wittkowski from ESO. "We estimate that the belt of gas and dust that surrounds it contains between 3 and 9 solar masses, which means that the star has already lost between one tenth and a third of its initial mass." To reach this conclusion, the team of astronomers used the MIDI instrument to combine the light collected by three pairs of 8.2-m Unit Telescopes of the VLT. This is the first time that MIDI has been used to study an individual star outside our Galaxy. The observations allowed the astronomers to clearly resolve the star. Comparisons with models led them to conclude that the star is surrounded by a gigantic, thick torus, expanding from about 15 stellar radii (or 120 times the distance between the Earth and the Sun - 120 AU!) to more than 250 stellar radii (or 30 000 AU!). "Everything is huge about this system. The star itself is so big that it would fill almost all the space between the Sun and the orbit of Saturn," says Ohnaka. "And the torus that surrounds it is perhaps a light-year across! Still, because it is so far away, only the power of interferometry with the VLT could give us a glimpse on this object. "

  4. Negative Corona Flashes Associated with Negative Stepped Leaders as a Source of Runaway Electrons

    NASA Astrophysics Data System (ADS)

    Pasko, V. P.; Moss, G. D.; Liu, N.

    2005-12-01

    In the presence of sufficiently strong electric fields ~10E_k in a weakly ionized plasma, where E_k is the conventional breakdown threshold field defined by the equality of the ionization and dissociative attachment coefficients in air, a fraction of initially low energy (~several eV) electrons can be directly accelerated over the peak of the dynamic friction force of electrons in air and become thermal runaway electrons [Gurevich, Sov. Phys. JETP, 12, 904, 1961]. Streamers are filamentary plasmas, which are driven by highly nonlinear space charge waves. The enhancement of electric fields around tips of streamers is one of the unique naturally occurring circumstances in which fields ~10E_k can be dynamically produced and sustained for relatively extended periods of time. The ability of these streamer tip fields to generate runaway electrons was identified and discussed in the literature over two decades ago [Babich, Sov. Phys. Dokl., 263, 76, 1982, and references therein]. Streamers are known to act as building blocks of streamer zones of conventional lightning leaders. It is also believed that the filamentary plasma structures observed in blue jets and gigantic jets, which emanate from the tops of thunderclouds, are directly linked to the processes in streamer zones of lightning leaders. In this talk we will discuss a probable scenario of events in which non-relativistic thermal runaway electrons emitted from the tips of streamers in the streamer zones of lightning leaders can be accelerated to relativistic energies. With total potential differences on the order of tens of MV available in streamer zones of lightning leaders, it is proposed that during a highly transient negative corona flash stage of the development of negative stepped leader, electrons with energies 2-8 keV ejected from streamer tips near the leader head [Moss et al., Eos. Trans. AGU, 85(47), Fall Meeting Suppl., Abstract AE31A-0158, 2004; JGR, in review, 2005; Liu et al., 2005 Seminar Series on TGFs, SSL, UC Berkeley, February 15, 2005, http://sprg.ssl.berkeley.edu/atmos/Agenda_Feb_15_Seminar.htm] can be further accelerated to energies of hundreds of keV and possibly to several tens of MeV, depending on particular magnitude of the leader head potential. It is proposed that these energetic electrons may be responsible (through the bremsstrahlung process) for the generation of hard X-rays observed from ground and satellites preceding lightning discharges, or with no association with lightning discharges in cases when the leader process does not culminate in a return stroke [e.g., Fishman et al., Science, 264, 1313, 1994; Inan et al., GRL, 23, 1017, 1996; Moore et al., GRL, 28, 2141, 2001; Dwyer et al., GRL, 32, L01803, 2005; Smith et al., Science, 307, 1085, 2005; Cummer et al., GRL, 32, L08811, 2005; and references therein]. For a lightning leader carrying a current of 100 A, an initial flux of ~2-8 keV thermal runaway electrons integrated over the cross sectional area of the leader is estimated to be ~1020 s-1 [Moss et al., JGR, in review, 2005], with the number of electrons accelerated to relativistic energies depending on the particular field magnitude and configuration in the leader streamer zone during the negative corona flash stage of the leader development. The duration of the negative corona flash and associated energetic radiation is estimated to be in the range from ~1 ?s to ~1 ms depending mostly on the pressure dependent size of the leader streamer zone.

  5. HUBBLE UNCOVERS DUST DISK AROUND A MASSIVE BLACK HOLE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Resembling a gigantic hubcap in space, a 3,700 light-year-diameter dust disk encircles a 300 million solar-mass black hole in the center of the elliptical galaxy NGC 7052. The disk, possibly a remnant of an ancient galaxy collision, will be swallowed up by the black hole in several billion years. Because the front end of the disk eclipses more stars than the back, it appears darker. Also, because dust absorbs blue light more effectively than red light, the disk is redder than the rest of the galaxy (this same phenomenon causes the Sun to appear red when it sets in a smoggy afternoon). This NASA Hubble Space Telescope image was taken with the Wide Field and Planetary Camera 2, in visible light. Details as small as 50 light-years across can be seen. Hubble's Faint Object Spectrograph (replaced by the STIS spectrograph in 1997) was used to observe hydrogen and nitrogen emission lines from gas in the disk. Hubble measurements show that the disk rotates like an enormous carousel, 341,000 miles per hour (155 kilometers per second) at 186 light-years from the center. The rotation velocity provides a direct measure of the gravitational force acting on the gas by the black hole. Though 300 million times the mass of our Sun, the black hole is still only 0.05 per cent of the total mass of the NGC 7052 galaxy. Despite its size, the disk is 100 times less massive than the black hole. Still, it contains enough raw material to make three million sun-like stars. The bright spot in the center of the disk is the combined light of stars that have crowded around the black hole due to its strong gravitational pull. This stellar concentration matches theoretical models linking stellar density to a central black hole's mass. NGC 7052 is a strong source of radio emission and has two oppositely directed `jets' emanating from the nucleus. (The jets are streams of energetic electrons moving in a strong magnetic field and unleashing radio energy). Because the jets in NGC 7052 are not perpendicular to the disk, it may indicate that the black hole and the dust disk in NGC 7052 do not have a common origin. One possibility is that the dust was acquired from a collision with a small neighboring galaxy, after the black hole had already formed. NGC 7052 is located in the constellation of Vulpecula, 191 million light-years from Earth. Credit: Roeland P. van der Marel (STScI), Frank C. van den Bosch (Univ. of Washington), and NASA. A caption and image files are available via the Internet at http://oposite.stsci.edu/pubinfo/1998/22.html.

  6. Convection in tropical cyclones associated with vapor volume reduction - a new concept

    NASA Astrophysics Data System (ADS)

    Mardhekar, D.

    2010-09-01

    Low pressure zone formation due to convection in a tropical cyclone is associated by a newly discovered phenomenon. The explanation is based on Avogadro's law. According to the law 18 grams (molecular weight expressed in grams) of water when evaporated occupies 22.414 litres of vapor at standard temperature and pressure (STP). Therefore, 1.0 gram of water in the vapor form will occupy 1.245 litres. That is, 1245 ml volume of vapor at STP when condensed will form 1.0 ml volume of water. Due to the phase change that is from water vapor to liquid water, huge reduction in volume occurs. The process of condensation of vapor into liquid water from the vapor component of the vapor-rich air is continuously taking place in a tropical cyclone particularly in the eye wall on a very large scale. The condensed water precipitates as rain or forms clouds. Each ml of the rain leaves behind a vacant space equal to 1245 ml forming a low-pressure zone and consequently a pressure gradient force is formed. Therefore, when there are continuous heavy rains in the eye wall, the magnitude of the low pressure zone and the pressure gradient force forming continuously in the condensation regions of the eye wall is gigantic. At the same time the latent heat released in the condensation process is absorbed by the remaining air component, it becomes warmer and buoyant, therefore ascends and ultimately escapes from the top of the cyclone as the outflow, again forming a low pressure zone. Thus, continuous condensation and continuous ascent and escape of warm air from the top together form a continuous pressure gradient and the vapour-rich air is continuously sucked up from below, that is from above the sea surface in the region of the eye wall due to the continuously forming pressure gradient force maintaining the near sea surface convergence of the vapour rich air. The value 1245 changes with change in temperature and pressure, but it does not affect the presented concept. The formation of the low pressure zone due to the condensation is instantaneous. The moment the condensation takes place, the low pressure zone and the consequent pressure gradient force is formed at that instant, hence this phenomenon enhances the fuel input process. Thus, the combination of the convection and the low pressure zone formation due to condensation and vapor volume reduction plays a combined role in the dynamics of a tropical cyclone. In case of tornadoes in the tornado alley, tornadoes are formed where warm vapor-rich air from the Gulf of Mexico meets the cold dry air from Canada. Here the same phenomena of vapor volume reduction and consequent formation of the low pressure zone as explained above is dominantly contributing in initiating and maintaining the flow of air forming a tornado. Since this phenomenon is taking place on land and vapour supply is limited, the tornadoes have a short life span.

  7. Radio Telescopes Reveal Unseen Galactic Cannibalism

    NASA Astrophysics Data System (ADS)

    2008-06-01

    Radio-telescope images have revealed previously-unseen galactic cannibalism -- a triggering event that leads to feeding frenzies by gigantic black holes at the cores of galaxies. Astronomers have long suspected that the extra-bright cores of spiral galaxies called Seyfert galaxies are powered by supermassive black holes consuming material. However, they could not see how the material is started on its journey toward the black hole. Optical/Radio Comparison Visible-light (left) and radio (right) image of galaxy pair: Radio image shows gas streaming between galaxies. CREDIT: Kuo et al., NRAO/AUI/NSF Click on image for more graphics. One leading theory said that Seyfert galaxies have been disturbed by close encounters with neighboring galaxies, thus stirring up their gas and bringing more of it within the gravitational reach of the black hole. However, when astronomers looked at Seyferts with visible-light telescopes, only a small fraction showed any evidence of such an encounter. Now, new images of hydrogen gas in Seyferts made using the National Science Foundation's Very Large Array (VLA) radio telescope show the majority of them are, in fact, disturbed by ongoing encounters with neighbor galaxies. "The VLA lifted the veil on what's really happening with these galaxies," said Cheng-Yu Kuo, a graduate student at the University of Virginia. "Looking at the gas in these galaxies clearly showed that they are snacking on their neighbors. This is a dramatic contrast with their appearance in visible starlight," he added. The effect of the galactic encounters is to send gas and dust toward the black hole and produce energy as the material ultimately is consumed. Black holes, concentrations of matter so dense that not even light can escape their gravitational pull, reside at the cores of many galaxies. Depending on how rapidly the black hole is eating, the galaxy can show a wide range of energetic activity. Seyfert galaxies have the mildest version of this activity, while quasars and blazars are hundreds of times more powerful. The astronomers picked a number of relatively nearby Seyfert galaxies that had previously been observed with visible-light telescopes. They then carefully studied the Seyferts with the VLA, specifically looking for radio waves emitted by hydrogen atoms. The VLA images showed the vast majority of the Seyferts were disturbed by encounters with neighbor galaxies. By comparison, similar VLA images of inactive galaxies showed that very few were disturbed. "This comparison clearly shows a connection between close galactic encounters and the black-hole-powered activity in the cores," said Ya-Wen Tang, who began this work at the Institute of Astronomy & Astrophysics, Academia Sinica (ASIAA), in Taiwan and now is a graduate student at the National Taiwan University. "This is the best evidence yet for the fueling of Seyfert galaxies. Other mechanisms have been proposed, but they have shown little if any difference between Seyferts and inactive galaxies," Tang added. "Our results show that images of the hydrogen gas are a powerful tool for revealing otherwise-invisible gravitational interactions among galaxies," said Jeremy Lim, also of ASIAA. "This is a welcome advance in our understanding of these objects, made possible by the best and most extensive survey ever made of hydrogen in Seyferts," Lim said. Kuo, Tang and Lim worked with Paul Ho, of ASIAA and the Harvard-Smithsonian Center for Astrophysics. The scientists reported their findings in the Astrophysical Journal. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  8. Contamination of soils with heavy metals and metalloids in the vicinity of the Erdenet copper-molybdenum mining area in Mongolia

    NASA Astrophysics Data System (ADS)

    Timofeev, Ivan; Kosheleva, Natalia; Gunin, Petr; Bazha, Sergei; Enkh-Amgalan, Sandag

    2014-05-01

    The present study was conducted to assess soil contamination taking place in Erdenet, the Mongolian city with a gigantic ore-mining and ore-dressing complex that was founded mainly to exploit the area's huge deposits of copper and molybdenum ore. The objectives of the study were: (1) to determine the content of heavy metals and metalloids (HMs) in soils of background and urban landscapes and to evaluate environmental hazard of HMs pollution; (2) to compile geochemical maps and to define zones with anomalously high concentrations of toxic elements in the city, (3) to identify spatial patterns and leading factors of pollutant accumulation. Sampling was performed in 2011 using regular spacing of 500-700m. In total 225 samples were collected from surface soil horizons (0 - 10 cm) in different functional areas of the city and in the background area located 5-6km from the city. The sampling scheme in background area took into account the topography and geological heterogeneity of the study area. The bulk contents of HMs in soil samples were analyzed by mass spectrometry and inductively coupled mass spectrometry (ICP-MS). Background concentrations of HMs were estimated for several soil groups formed on specific parent rocks and were compared with their global abundances in soils. The pollution of urban soils was evaluated using background soils as reference objects. Associations of HMs were identified according to the enrichment factor (EF) values and using cluster analysis with complete linkage algorithm. Visualization of soil-geochemical data was performed by local interpolation or kriging method in MapInfo 11.5 and Surfer 11. Multiple regression analysis (decision trees method) was applied to determine soil properties and landscape factors that may control HMs accumulation in soils. Background soils formed on granite and granodiorite of Permian-Selenga complex occupy the largest area and are characterized by high concentrations of V, Cr, Co, Ni, Zn, Sr, Cu, Zn, Mo and W. The lowest concentrations of the elements are typical of soils formed on triassic volcanic suite and sub-volcanic intrusions. Urban soils are heavily polluted in industrial zone, where accumulation of Mo (EF=10.7) and Cu (10.6) are the highest among other elements (Se, As, Sb, W, EF=2.4-1.5). The mining area and the landscapes in its immediate vicinity are characterized by high and dangerous level of multi-elemental contamination while the most part of the urban territory has low level of contamination. Soils in all functional zones, with the exception of the ger district, have elevated concentrations of Mo, Cu and Se. Three geochemical associations W-Bi-Cd-Sn-Zn-Pb; Cu-As-Sb-Mo and V-Co-Sr-Cr-Ni have been identified in urban soils. The maximum concentrations of the elements in the first two groups are typical of the disturbed soils adjacent to the plant and tailings area (EFs for individual elements range from1.4 to1080). Statistical analysis revealed that such soil characteristics as grain-size distribution, pH, humus content have a direct impact on HMs fixation in urban soils while the influence of landscape factors (topography, lithology, functional assignment) is not so evident.

  9. Tarasca: ritual monster of Spain.

    PubMed

    Gilmore, David D

    2008-09-01

    Let us now revisit our original assumptions. First, we note that for the participants in Hacinas Carnival the Tarasca is a figure of fun and joy, but it also exudes a strain of aggressive misogyny that many female residents, not to mention tourists, find somewhat unsettling. In the spirit of feminist currents in Spain, a group of young women protested in 1992 to town officials and, when rebuffed, sought to build their own female monster, which they intended to use to attack boys and men. While their plan was never carried out, and indeed met with stiff opposition from officialdom and, especially, from older women, some of the younger, more modern girls find the Tarasca appalling, and they told me so without compunction. Accordingly, today the festival tends to polarize the sexes as well as the generations. Also, many children are frightened by the gigantic mock-up with its snapping teeth and foul breath, and many of them burst into tears at the roaring of the demons. But despite these negatives--or perhaps because of them--the Tarasca breaks down boundaries between things normally kept separate in the mind: humor and terror, man and beast, order and disorder, old and young, life and death, and so on. In so collapsing opposites, the Tarasca causes people to pause and to think about and question everyday reality in the non-Carnival universe. All these observations of course support the structural arguments of our four theorists above and in particular seem to corroborate Bloch's concept (1992) of the regenerative power of "rebounding violence." However, there are three specific features here that need psychological amplification beyond simply confirming the work of previous theorists. We must first note that like most grotesque fantasies, the Hacinas monster combines disparate organic "realities" into a bizarre and monstrous image that by its very oddness and the resulting "cognitive mismatch" captures people's attention and sparks the imagination, especially that of children (Konner 2002, 222). The Pentecostal beastie combines equine, reptilian, and bird-like features with a giraffe's neck, an elephant's bulk, an impossible number of legs, the usual human malevolence, and the satyr's insatiable lust. The monster also combines cognitive antitheses in a way that reinforces cultural biases while at the same time undermining them--a typical paradox of the Monstrous in ritual and art (Andriano 1999). In the Hacinas festival the integrated themes are those of bodily mutilation, sexual abuse, cannibalism, death, and decay. All these themes come together in certain compelling Iberian traditions: misogyny, costumed parading, religious revitalization, ritual displacement of aggression onto external objects, spontaneous street theatre. All forms of aggression are visually embodied in the image of the mystic beast, as happens every day in the classic Spanish bullfight pitting man against raw nature (Mitchell 1991). Peremptory male sexuality both parodied and glorified, women both raped and rescued, children both terrified and liberated. As Bloch has argued in the aptly titled Prey into Hunter (1992), the narrative of the Tarasca rite, turning victim into victimizer, enables the community to "absorb the vitality" of the external threat and thereby to regenerate itself and to transcend everyday reality. We may make a third, psychoanalytic, observation. As with all such fabulous and scary images, the Tarasca provokes regressive responses that probably go back to the primary organization of the mind before the advent of speech. In this childhood environment, sensations are limited to visions and primary emotions, and the world is experienced largely through the eyes and mouth. Psychoanalysts of childhood have called this the phase of oral/visual primacy. It may explain the locus of aggression in typical monster imagery: the rending teeth, the gnashing jaws, the cavernous belly. It would also help us understand the terror at being devoured by a giant predator during the ritual or, as Bloch puts it (

  10. The Yangtze-Project

    NASA Astrophysics Data System (ADS)

    Subklew, Gnter; Ulrich, Julia; Frst, Leander; Hltkemeier, Agnes

    2010-05-01

    As an important element in Chinese politics for the development of the Western parts of the country, a large hydraulic engineering project - the Three Gorges Dam - has been set up in order to dam the Yangtze River for a length of over 600 km with an average width of about 1,100 m. It is expected that this results in ecological, technical and social problems of a magnitude hardly dealt with before. With this gigantic project, the national executive is pursuing the aims of - preventing flooding - safeguarding the water supply - encouraging navigation and - generating electric energy. In future, fluctuations of the water level of up to 30 metres will be deliberately applied in the dammed-up section of the river while retaining the flow character of the seasonal variation. The pollution of the Yangtze with a wide range of problem substances is frequently underestimated since in many cases attention is only paid to the low measured concentrations. However, the large volumes of water lead to appreciable loads and thus the danger of an accumulation of pollutants even reaching the human food chain. It should also not be forgotten that the Yangtze represents the major, and in some cases indeed the only, source of drinking and domestic water for the population. A consideration of the water level in the impoundment that will in future arise from management of the reservoir reveals the dramatic change in contrast to the natural inundation regime. In the past, the flood events on the banks of the Yangtze and its tributaries occurred in the summer months. The plants in the riparian zone (water fluctuation zone = WFZ) were previously inundated during the warmer time of year (28 July/August) and the terrestrial phase of the WFZ was characterized by cool temperatures (3-5 C January) that permitted little plant activity. In future, the highest water levels will occur in winter above the dam on the Yangtze and also on the tributaries flowing into it. The plants in the WFZ will then encounter considerably improved climatic conditions with higher temperatures during their physiologically active season in the summer months. This reversal of the flood pulse in the course of the year will exert an enormous influence on the fauna and flora and the associated processes. Other parameters resulting from the management of the reservoir are the sediment deposits and their varying extents in the different zones of the WFZ. For example, the different degrees of compaction of the sediment of the river bank will largely determine the exchange of oxygen, nutrients and metabolites between the plants and the water body and thus the major ecosystem functions. The locally different thicknesses of the sediment body will be decisive for the emergence of plant shoots through the sediment. In areas of high flow rates, in contrast, habitats will be established that are strongly characterized by the dynamics of the pebbles and boulders. The Three Gorges Project will thus bring about a significant change in habitat conditions for vegetation in the WFZ whose consequences cannot yet be predicted with any certainty. This also concerns the potential and long-term impacts of changed vegetation on the local population, who exploit the plant resources, and also on tourism and on the hydroregime and the sedimentation regime in the reservoir. Landslides and rock falls are the major geological events in the Three Gorges region. The mud and debris avalanches formed during such landslips represent a danger both for areas of settlement and also for land used industrially and agriculturally, as well as for infrastructure facilities, and may also considerably obstruct navigation. Furthermore, the analogous mass movements are one of the reasons for the silting up of the Yangtze and many of its tributaries. The region of the Three Gorges contains rapidly growing urban centres that will receive further impulses for growth from the dam project. The fact that the Chongqing conurbation, with more than 30 million inhabitants the "largest city in the world", is directly und

  11. Chandra Helps Put The Pieces Together On Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    2000-11-01

    NASAs Chandra X-ray Observatory has detected never-before-seen properties in the X-ray afterglow of a gamma-ray burst. This discovery strengthens the case for a hypernova model, where massive collapsed stars generate these mysterious blasts of high-energy radiation believed to be the most powerful explosions in the universe. An international team of scientists used Chandra to observe iron emission lines from ejected material surrounding the gamma-ray burst (GRB) known as GRB991216. This is the first time emission lines associated with GRBs have been unambiguously detected and their properties precisely measured at X-ray wavelengths. Astronomers have long debated how GRBs originate. One theory contends that GRBs result when two compact objects, that is, neutron stars or black holes, collide and coalesce. Another theory speculates that a hypernova, a gigantic star collapsing on itself under its own weight, could cause these extremely energetic outbursts. The discovery of iron lines in the X-ray spectrum is an important clue to our understanding of GRBs, said Luigi Piro, lead author of the paper that appeared in the November 3 issue of the journal Science. Studying the immediate area around the GRB tells us a great deal about the origin of the GRB itself. A shift in the wavelength, or energy, of the detected iron line emission (relative to what would be seen in a laboratory) tells the researchers the distance to the GRB. The Chandra team determined that it has taken roughly 8 billion years for the X rays from GRB991216 to reach the Earth, in agreement with an independent estimate from an absorption feature in the optical light from the host galaxy. From the distance and the intensities of the detected X-ray emission lines, the investigators deduced the properties of the ejected material and its relationship to the GRB. The team was able to determine the mass of the medium within a light day or two of the GRB as approximately equivalent to at least one-tenth that of the Sun. By analyzing the widths of the detected spectral lines, the researchers found that the material surrounding GRB991216 is moving away very quickly (approximately 10 percent the speed of light). The most straightforward scenario that emerges from all of the evidence we have gathered is that a massive progenitor - like a hypernova - ejects matter, shortly before the GRB, said Piro. In other words, our data helps rule out the scenario where two neutron stars or black holes collide. We think GRBs result from something similar to a supernova explosion, but much more powerful. Although still unclear, scientists speculate that the initial shedding of material (perhaps the outer envelope of the hypernova) is followed by an event (the GRB) at the core of the hypernova - most likely a collapse to a black hole. Energy released by the fireball of the GRB would then heat up the previously ejected material, producing the optical and X-ray afterglows lasting days or weeks after the GRB. While GRB afterglows have been studied in the optical, radio, and X-ray regimes for some time, high precision X-ray observations were needed to measure the properties of dense, massive medium that would exist if the scenario of a massive progenitor were true. With Chandra, the scientists believe they are seeing the iron emission that is predicted if the surrounding medium becomes heavily ionized and recombination takes place after being hit with the radiation produced by the GRB and its afterglow. GRB991216, first detected by the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-ray Observatory on December 16, 1999, was one of the brightest GRBs ever found by that instrument. A more accurate GRB position was obtained by the Rossi X-ray Transient Explorer. Chandra was able to reorient quickly in order to observe the event on December 18, while the flux level was still high. This allowed Piro and his team to observe GRB991216, using Chandras High Energy Grating Spectrometer (HETG) in conjunction with the Advanced CCD Imag

  12. Charting the Giants

    NASA Astrophysics Data System (ADS)

    2004-06-01

    Largest Census Of X-Ray Galaxy Clusters Provides New Constraints on Dark Matter [1] Clusters of galaxies Clusters of galaxies are very large building blocks of the Universe. These gigantic structures contain hundreds to thousands of galaxies and, less visible but equally interesting, an additional amount of "dark matter" whose origin still defies the astronomers, with a total mass of thousands of millions of millions times the mass of our Sun. The comparatively nearby Coma cluster, for example, contains thousands of galaxies and measures more than 20 million light-years across. Another well-known example is the Virgo cluster at a distance of about 50 million light-years, and still stretching over an angle of more than 10 degrees in the sky! Clusters of galaxies form in the densest regions of the Universe. As such, they perfectly trace the backbone of the large-scale structures in the Universe, in the same way that lighthouses trace a coastline. Studies of clusters of galaxies therefore tell us about the structure of the enormous space in which we live. The REFLEX survey ESO PR Photo 18a/04 ESO PR Photo 18a/04 Galaxy Cluster RXCJ 1206.2-0848 (Visible and X-ray) [Preview - JPEG: 400 x 478 pix - 70k] [Normal - JPEG: 800 x 956 pix - 1.2Mk] Caption: PR Photo 18a shows the very massive distant cluster of galaxies RXCJ1206.2-0848, newly discovered during the REFLEX project, and located at a redshift of z = 0.44 [3]. The contours indicate the X-ray surface brightness distribution. Most of the yellowish galaxies are cluster members. A gravitationally lensed galaxy with a distorted, very elongated image is seen, just right of the centre. The image was obtained with the EFOSC multi-mode instrument on the ESO 3.6-m telescope at the La Silla Observatory (Chile). ESO PR Photo 18b/04 ESO PR Photo 18b/04 Galaxy cluster RXCJ1131.9-1955 [Preview - JPEG: 400 x 477 pix - 40k] [Normal - JPEG: 800 x 953 pix - 912k] [FullRes - JPEG: 2251 x 2681 pix - 7.7Mk] Caption: PR Photo 18b displays the very massive galaxy cluster RXCJ1131.9-1955 at redshift z = 0.306 [3] in a very rich galaxy field with two major concentrations. It was originally found by George Abell and designated "Abell 1300". The image was obtained with the ESO/MPG 2.2-m telescope and the WFI camera at La Silla. ESO PR Photo 18c/04 ESO PR Photo 18c/04 Galaxy Cluster RXCJ0937.9-2020 [Preview - JPEG: 400 x 746 pix - 60k] [Normal - JPEG: 800 x 1491 pix - 1.3M] [HiRes - JPEG: 2380 x 4437 pix - 14.2M] Caption: PR Photo 18c/04 shows the much smaller, more nearby galaxy group RXCJ0937.9-2020 at a redshift of z = 0.034 [3]. It is dominated by the massive elliptical galaxy seen at the top of the image. The photo covers only the southern part of this group. Such galaxy groups with typical masses of a few 1013 solar masses constitute the smallest objects included in the REFLEX catalogue. This image was obtained with the FORS1 multi-mode instrument on the ESO 8.2-m VLT Antu telescope. ESO PR Video Clip 05/04 ESO PR Video Clip 05/04 Galaxy Clusters in the REFLEX Catalogue (3D-visualization) [MPG - 11.7Mb] Caption: ESO PR Video Clip 05/04 illustrates the three-dimensional distribution of the galaxy clusters identfied in the ROSAT All-Sky survey in the northern and southern sky. In addition to the galaxy clusters in the REFLEX catalogue this movie also contains those identified during the ongoing, deeper search for X-ray clusters: the extension of the southern REFLEX Survey and the northern complementary survey that is conducted by the MPE team at the Calar Alto observatory and at US observatories in collaboration with John Huchra and coworkers at the Harvard-Smithonian Center for Astrophysics. In total, more than 1400 X-ray bright galaxy cluster have been found to date. (Prepared by Ferdinand Jamitzky.) Following this idea, a European team of astronomers [2], under the leadership of Hans Bhringer (MPE, Garching, Germany), Luigi Guzzo (INAF, Milano, Italy), Chris A. Collins (JMU, Liverpool), and Peter Schuecker (MPE, Garching) has embarked on a decade-long study of these garga

  13. The Payun-Matru lava field: a source of analogues for Martian long lava flows

    NASA Astrophysics Data System (ADS)

    Giacomini, L.; Pasquar, G.; Massironi, M.; Frigeri, A.; Bistacchi, A.; Frederico, C.

    2007-08-01

    The Payun Matru Volcanic complex is a Quaternary fissural structure belonging to the back-arc extensional area of the Andes in the Mendoza Province (Argentina). The eastern portion of the volcanic structure is covered by a basaltic field of pahoehoe lava flows advanced over more than 180 km from the fissural feeding vents that are aligned with a E-W fault system (Carbonilla fault). Thanks to their widespread extension, these flows represent some of the largest lava flows in the world and the Pampas Onduladas flow can be considered the longest sub-aerial individual lava flow on the Earth surface [1,2]. These gigantic flows propagated over the nearly flat surface of the Pampean foreland, moving on a 0.3 degree slope. The very low viscosity of the olivine basalt lavas, coupled with the inflation process and an extensive system of lava tubes are the most probable explanation for their considerable length. The inflation process likely develop under a steady flow rate sustained for a long time [3]. A thin viscoelastic crust, built up at an early stage, is later inflated by the underlying fluid core, which remains hot and fluid thanks to the thermal-shield effect of the crust. The crust is progressively thickened by accretion from below and spreading is due to the continuous creation of new inflated lobes, which develop at the front of the flow. Certain morphological features are considered to be "fingerprints" of inflation [4, 5, 6]; these include tumuli, lava rises, lava lobes and ridges. All these morphologies are present in the more widespread Payun Matru lava flows that, where they form extensive sheetflows, can reach a maximum thickness of more than 20 meters. After the emplacement of the major flows, a second eruptive cycle involved the Payun Matru volcanic structure. During this stage thick and channelized flows of andesitic and dacitic lavas, accompanied the formation of two trachitic and trachiandesitic strato-volcanoes (Payun Matru and Payun Liso) culminated with the Payun Matru summit caldera development [7]. Finally a new phase of basaltic volcanism developed from Carbonilla Fault and was associated again with pahoehoe lavas and, at the final stage, by very long "aa" lava flows characterized by spectacular channel-levees systems. Hence, the Payun Matru lava field shows a multiplicity of flow surface morphologies linked to different lava types and related emplacement mechanisms, therefore it can represent an outstanding analogue of several Martian flows. In addition, the understanding of propagation processes of Payun Matru exceptionally widespread flows can give important clues in the comprehension of emplacement mechanisms of the long flows on Mars. Remote sensing data used to map and observe the Payun Matru can be compared with data acquired by similar instruments from various scientific missions to Mars. Mars Global Surveyor's Mars Orbiter Camera (MOC) data has been used to observe the morphology of the Martian lava flows with a resolution of about 10 meters per pixel in order to compare them with the Payn Matru lava flows. The Mars Orbiter Laser Altimeter (MOLA) was used to investigate the topographic environment over which flows propagated, whereas HRSC data are needed to possibly determine flow thickness and morphological variability. Arsia Mons lava field that includes the longest flows on Mars [8] shows many analogues of the Payun Matru lava flows since it is mainly characterized by sheet-flows with uniform ridged surface texture locally showing features like lava rises and lava tubes. In particular the extensive flow field in Daedalia Planum, at about 300 km south-west of Arsia Mons, is characterized by lobes reaching several kilometeres in length, although the slope of the region is generally minor of 0,5 degree [9]. Therefore it is very likely that inflation is the main emplacement process of these long flows. The presence of tumuli and lava ridges, detected in several areas of the lava field, seems to support this hypothesis. According to this view some linear features at the flow su

  14. Distant Supernovae Indicate Ever-Expanding Universe

    NASA Astrophysics Data System (ADS)

    1998-12-01

    ESO Astronomers Contribute towards Resolution of Cosmic Puzzle Since the discovery of the expansion of the Universe by American astronomer Edwin Hubble in the 1920's, by measurement of galaxy velocities, astronomers have tried to learn how this expansion changes with time. Until now, most scientists have been considering two possibilities: the expansion rate is slowing down and will ultimately either come to a halt - whereafter the Universe would start to contract, or it will continue to expand forever. However, new studies by two independent research teams, based on observations of exploding stars ( supernovae ) by ESO astronomers [1] with astronomical telescopes at the La Silla Observatory as well as those of their colleagues at other institutions, appear to show that the expansion of the Universe is accelerating . The results take the discovery of the cosmological expansion one step further and challenge recent models of the Universe. If the new measurements are indeed correct, they show that the elusive "cosmological constant" , as proposed by Albert Einstein , contributes significantly to the evolution of the Universe. The existence of a non-zero cosmological constant implies that a repulsive force, counter-acting gravity, currently dominates the universal expansion , and consequently leads to an ever-expanding Universe. This new research is being named as the "Breakthrough of the Year" by the renowned US science journal Science in the December 18, 1998, issue. A Press Release is published by the journal on this occasion. "Fundamental Parameters" of the Universe Three fundamental parameters govern all cosmological models based on the theory of General Relativity. They are 1. the current expansion rate as described by Hubble's constant , i.e. the proportionality factor between expansion velocity and distance 2. the average matter density in the Universe, and 3. the amount of "other energy" present in space. From the measured values of these fundamental parameters, the age of the Universe and the geometry of space can be derived. They have been the focus of a large number of astronomical programmes over the past decades. Many aspects of the currently preferred cosmological model, the Hot Big Bang , have been impressively confirmed by observations of the expansion of the Universe, the cosmic background radiation, and also the explanation of the synthesis of light elements. Still, our knowledge about the dynamical state of the Universe, as well as the early formation of structures, i.e., of galaxies and stars, is far from complete - this remains a field of active research. Possibly, the simplest way to test our present assumptions in this direction is to measure accurate distances and compare them with the expected cosmic scale. This is where the recent results contribute to our understanding of the Universe. The key role of supernovae The two research teams, both with participation from ESO [1], have concentrated on the study of rare stellar explosions, during which certain old stars undergo internal incineration. In this process, explosive nuclear fusion burns matter into the most stable atomic nucleus, iron, and releases a gigantic amount of energy. ESO PR Photo 50a/98 ESO PR Photo 50a/98 [Preview - JPEG: 800 x 648 pix - 768k] [High-Res - JPEG: 3000 x 2431 pix - 8.5Mb] ESO PR Photo 50b/98 ESO PR Photo 50b/98 [Preview - JPEG: 800 x 649 pix - 784k] [High-Res - JPEG: 3000 x 2432 pix - 8.4Mb] These photos illustrate the follow-up observations on which the new results described in this Press Release are based. Sky fields with clusters of galaxies are monitored with the 4-m telescope at Cerro Tololo Interamerican Observatory (CTIO) in Chile and spectra are obtained of suddenly appearing star-like objects that may be supernovae. Confirmed Type Ia supernovae are then monitored by ESO telescopes at La Silla and at other observatories. In PR Photo 50a/98 , a supernova at redshift z = 0.51 [2] (corresponding to a distance of about 10,000 million light-years) is observed on five dates with

  15. Portrait of a Dramatic Stellar Crib

    NASA Astrophysics Data System (ADS)

    2006-12-01

    A new, stunning image of the cosmic spider, the Tarantula Nebula and its surroundings, finally pays tribute to this amazing, vast and intricately sculpted web of stars and gas. The newly released image, made with ESO's Wide Field Imager on the 2.2-m ESO/MPG Telescope at La Silla, covers 1 square degree on the sky and could therefore contain four times the full Moon. ESO PR Photo 50a/06 ESO PR Photo 50a/06 The Tarantula Nebula (WFI/2.2m) Known as the Tarantula Nebula for its spidery appearance, the 30 Doradus complex is a monstrous stellar factory. It is the largest emission nebula in the sky, and can be seen far down in the southern sky at a distance of about 170,000 light-years, in the southern constellation Dorado (The Swordfish or the Goldfish). It is part of one of the Milky Way's neighbouring galaxies, the Large Magellanic Cloud. The Tarantula Nebula is thought to contain more than half a million times the mass of the Sun in gas and this vast, blazing labyrinth hosts some of the most massive stars known. The nebula owes its name to the arrangement of its brightest patches of nebulosity, that somewhat resemble the legs of a spider. They extend from a central 'body' where a cluster of hot stars (designated 'R136') illuminates and shapes the nebula. This name, of the biggest spiders on the Earth, is also very fitting in view of the gigantic proportions of the celestial nebula - it measures nearly 1,000 light-years across and extends over more than one third of a degree: almost, but not quite, the size of the full Moon. If it were in our own Galaxy, at the distance of another stellar nursery, the Orion Nebula (1,500 light-years away), it would cover one quarter of the sky and even be visible in daylight. Because astronomers believe that most of the stars in the Universe were formed in large and hectic nurseries such as the 30 Doradus region, its study is fundamental. Early this year, astronomers took a new, wide look at the spider and its web of filaments, using the Wide Field Imager on the 2.2-m MPG/ESO telescope located at La Silla, Chile, while studying the dark clouds in the region. Dark clouds are enormous clouds of gas and dust, with a mass surpassing a million times that of the Sun. They are very cold, with temperatures about -260 degrees Celsius, and are difficult to study because of the heavy walls of dust behind which they hide. Their study is however essential, as it is in their freezing wombs that stars are born. ESO PR Photo 50b/06 ESO PR Photo 50b/06 SN 1987A and the Honeycomb Nebula (WFI/2.2m) Observing in four different bands, the astronomers made a mosaic of the half-degree field of view of the instrument to obtain an image covering one square degree. With each individual image containing 64 million pixels, the resultant mosaic thus contained 4 times as many, or 256 million pixels! The observations were made in very good image quality, the 'seeing' being typically below 1 arcsecond. The image is based on data collected through four filters, including two narrow-band filters that trace hydrogen (red) and oxygen (green). The predominance of green in the Tarantula is a result of the younger, hotter stars in this region of the complex. It would be easy to get lost in the meanderings of the filamentary structures or get stuck in the web of the giant arachnid, as is easily experienced with the zoom-in feature provided on the associated photo page, and it is therefore difficult to mention all the unique objects to be discovered. Deserving closer attention perhaps is the area at the right-hand border of the Tarantula. It contains the remains of a star that exploded and was seen with the unaided eye in February 1987, i.e. almost 20 years ago. Supernova SN 1987A, as it is known, is the brightest supernova since the one observed by the German astronomer Kepler in 1604. The supernova is known to be surrounded by a ring, which can be distinguished in the image. A little to the left of SN 1987A, another distinctive feature is apparent: the Honeycomb Nebula. This characteristic bubble-like structure results apparently

  16. The Purple Rose of Virgo

    NASA Astrophysics Data System (ADS)

    2007-03-01

    Until now NGC 5584 was just one galaxy among many others, located to the West of the Virgo Cluster. Known only as a number in galaxy surveys, its sheer beauty is now revealed in all its glory in a new VLT image. Since 1 March, this purple cosmic rose also holds the brightest stellar explosion of the year, known as SN 2007af. Located about 75 million light years away towards the constellation Virgo ('the Virgin'), NGC 5584 is a galaxy slightly smaller than the Milky Way. It belongs, however, to the same category: both are barred spirals. ESO PR Photo 16/07 ESO PR Photo 16/07 The Purple Rose of Virgo Spiral galaxies are composed of a 'bulge' and a flat disc. The bulge hosts old stars and usually a central supermassive black hole. Younger stars reside in the disc, forming the characteristic spiral structures from which the galaxies get their name. Barred spirals are crossed by a bright band of stars. In 2000, using ESO's Very Large Telescope, astronomers discovered the smallest, faintest, and most massive spirals (see ESO PR 12/00 and 25/00). In this amazing new image of NGC 5584 two dominant spiral arms are clearly visible, while the others are deformed, probably due to interactions with other galaxies. Luminous patches are spread all over the disc, indicating that stars are being formed in this gigantic rose at a frantic pace. Something even brighter, however, catches the eye in this picture. Any image taken before the end of February would not have shown the luminous spot located at the lower right of the galaxy's centre. As can be seen, the newly found object is much brighter than the centre of the galaxy itself. Its name? SN 2007af, the 32nd supernova discovered this year. Its presence signals the dramatic death of a star with a mass comparable to that of the Sun. SN 2007af, the brightest supernova of the year (so far), was discovered on 1 March by the Japanese supernova hunter Koichi Itagaki. He pointed his 60-centimetre telescope towards the Virgo constellation and discovered something that was not there before: SN 2007af. When it was discovered, its brightness (apparent visible magnitude of 15.4) was about seven times fainter than that of its host galaxy, NGC 5584. It has since brightened by the same factor of 7, reaching an apparent magnitude of 13.3 and making it observable by many amateur astronomers with smaller telescopes. Observations on 4 March with ESO's New Technology Telescope at La Silla revealed that this energetic explosion is a Type Ia supernova that was observed a few days before it reached its maximal luminosity. Matter from the doomed star is ejected with velocities above 15,000 km/s. Astronomers are observing SN2007af with ESO's VLT, with the aim of studying the geometry of the material ejected by the supernova, and thereby better understanding the explosion mechanism (see also ESO 44/06). A Type Ia supernova is thought to be the result of the explosion of a small and dense star - a white dwarf - inside a binary system. As its companion continuously spills matter onto the white dwarf, the white dwarf reaches a critical mass, leading to a fatal instability and the supernova. Type Ia supernovae are apparently quite similar to one another. This gives them a very useful role as 'standard candles' that can be used to measure cosmic distances. Their peak brightness rivals that of their parent galaxy, hence qualifying them as prime cosmic yardsticks. Astronomers have exploited this fortunate circumstance to study the expansion history of our Universe. However Type Ia supernovae are rare events: a galaxy like the Milky Way may host a Type Ia supernova on average only every 400 years. Even so, SN 2007af is not the only brilliant detonation recently recorded in NGC 5584. Furthermore, it seems that Japanese amateur astronomers have a special talent for catching supernova explosions in this purple spiral. Indeed, in 1996 Aoki Masakatsu identified SN 1996aq in NGC 5584, a difficult to classify supernova subject to a hot discussion due to its ambiguous nature.

  17. Second Chandra Instrument Activated August 28

    NASA Astrophysics Data System (ADS)

    1999-08-01

    Cambridge, MA--NASA's Chandra X-ray Observatory opened a new era in astronomy Saturday, August 28, by making the most precise measurements ever recorded of the energy output from the 10 million degree corona of a star. Last weekend's observations came after the successful activation of an instrument developed by MIT that will allow a one-thousand-fold improvement in the capability to measure X-ray spectra from space. The new measurements, made with the High Energy Transmission Grating Spectrometer, join spectacular images taken last week by Chandra of the aftermath of a gigantic stellar explosion. The spectrometer is one of four key instruments aboard Chandra, and the second to be activated. The others will be turned on over the next two weeks. The spectrometer activated yesterday spreads the X-rays from Chandra's mirrors into a spectrum, much as a prism spreads light into its colors. The spectrum then can be read by Chandra's imaging detectors like a kind of cosmic bar code from which scientists can deduce the chemical composition and temperature of the corona. A corona is a region of hot gas and magnetic loops that extend hundreds of thousands of miles above the star's visible surface and is best studied with X-rays. "The success of the new spectrometer is definitely a major milestone for modern astronomy," said MIT Professor Claude R. Canizares, principal investigator for the instrument and associate director of the Chandra X-ray Observatory Center (CXC). "Within the first hour we had obtained the best X-ray spectrum ever recorded for a celestial source. We can already see unexpected features that will teach us new things about stars and about matter at high temperatures." The spectrometer measured X-rays from the star Capella, which is 40 light years away in the constellation Auriga. Capella is actually two stars orbiting one another and possibly interacting in ways that pump extra heat into the corona, which appears more active than that of the Sun. How a star manages to heat its corona to temperatures a thousand times higher than its own surface is still a puzzle, which astronomers hope can be solved by observations like this one. Other prime targets for Chandra's spectrometers over the next few months include black holes, quasars and supernova explosions. The grating spectrometer consists of hundreds of gold gratings, each about the size of a postage stamp. The surface of each grating resembles a precise picket fence, with microscopic gold pickets 500 times thinner than a human hair. These are spaced every 2000 angstroms, or less than half the wavelength of visible light. The instrument was developed at MIT's Center for Space Research, which Professor Canizares directs, by adapting techniques usually used to make computer chips. Some of these adaptations have found their way back as improvements in the chip-making industry. The grating spectrometer is one of two such devices carried by Chandra. The other, a low-energy grating built by a Dutch-German team, will be activated next week. Chandra also contains two detectors. One, built by researchers at Pennsylvania State University and MIT, was turned on two weeks ago and has recorded all the images and spectra seen so far. The second, built by the Smithsonian Astrophysical Observatory, is being activated this week. Dr. Stephen Murray of the Harvard-Smithsonian Center for Astrophysics summarized the expected impact of Chandra's high resolution X-ray spectroscopy with these words: "A picture is worth a thousand words, a spectrum is worth a million." Capella's spectrum and further information about Chandra's High Energy Transmission Grating Spectrometer may be found at: http://space.mit.edu/CSR/hetg_info.html The Chandra X-ray Observatory Center was named in honor of the late Nobel laureate Subrahmanyan Chandrasekhar. NASA's Marshall Space Flight Center manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science and f

  18. HUBBLE FINDS THOUSANDS OF GASEOUS FRAGMENTS SURROUNDING DYING STAR

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Resembling a bizarre setting from a science fiction movie, dramatic images sent back by NASA's Hubble Space Telescope have surprised astronomers by uncovering thousands of gigantic tadpole-shaped objects surrounding a dying star. Dubbed 'cometary knots' because their glowing heads and gossamer tails superficially resemble comets, they are probably the result of a dying star's final outbursts. Though ground-based telescopic observations have hinted at such objects, they have not previously been seen in such abundance, say researchers. The knots were detected by Hubble astronomer C. Robert O'Dell and graduate student Kerry P. Handron of Rice University in Houston, Texas, while exploring the Helix nebula, a ring of glowing gases blown off the surface of a sunlike star late in its life. O'Dell expects the gaseous knots, which are each several billion miles across, will eventually dissipate and vanish into the cold emptiness of interstellar space. However, he speculates that if the objects contract to form permanent solid bodies, they may contribute to a fraction (less than ten percent) of the missing mass of our galaxy, simply because of their sheer abundance around a typical dying star. (This so-called dark matter is a known source of gravity that affects the motions of stars in the galaxy). The mysterious 'space pods' came into view as O'Dell used Hubble's Wide Field Planetary Camera 2 to survey the Helix nebula, located 450 light-years away in the constellation Aquarius and the closest planetary nebula to Earth -- so close that its angular size is almost half that of the full Moon. The most visible cometary knots all lie along the inner edge of the ring, at a distance of trillions of miles from the central star. Their comet-like tails, each stretching a hundred billion miles, form a radial pattern around the star like the spokes on a wagon wheel. Though previous ground-based observations show a spoke pattern in the Helix, and some structure, O'Dell emphasizes that the Hubble images reveal an underlying population of many more smaller objects. O'Dell made the observation because he was curious if these objects were the result of the star's final outburst which would bring comets out of 'cold storage' by boiling off the icy, solid comet nuclei. This is how comets behave as they swing near our Sun. The knots have just the right appearance and are at just the right distance from the dying star to be a long-sought comet cloud -- much like the hypothesized Oort cloud encircling our solar system. However, each gaseous cometary 'head' is at least twice the diameter of our solar system -- far too large for the gaseous shell, called a coma, that surrounds an active comet as we know it. The most likely explanation is the objects have been formed during the final years of a star's life when it ejects shells of gas into space. This 'planetary nebula' formation happens in stages where, toward the end of the process, a faster moving shell of gas ejected off the doomed star collides with slower moving gas released ten thousand years before. This collision of hot, lower density gas with cooler, higher density gas forms an unstable condition where the two gases intermix and fragment the previously smooth cloud. This process, called a Rayleigh-Taylor instability, breaks the cloud into smaller and denser finger-like droplets, like dripping paint. Standard models predict that the knots should expand and dissipate within a few hundred thousand years. However, dust particles inside each gas ball might collide and stick together, snowballing to planet- sized bodies over time. The resulting objects would be like Earth- sized copies of the frigid, icy planet Pluto. These icy worlds would escape the dead star and presumably roam interstellar space forever. If this phenomena is common among stars, then our galaxy could be littered with trillions of these objects, O'Dell concludes. 'Planetary nebulae have been formed in our galaxy for billions of years and about one new one is created every year since this is the usual ending for the billions of sunl

  19. The Cosmic Bat - An Island of Stars in the Making on the Outskirts of Orion

    NASA Astrophysics Data System (ADS)

    2010-03-01

    The delicate nebula NGC 1788, located in a dark and often neglected corner of the Orion constellation, is revealed in a new and finely nuanced image that ESO is releasing today. Although this ghostly cloud is rather isolated from Orion's bright stars, the latter's powerful winds and light have had a strong impact on the nebula, forging its shape and making it home to a multitude of infant suns. Stargazers all over the world are familiar with the distinctive profile of the constellation of Orion (the Hunter). Fewer know about the nebula NGC 1788, a subtle, hidden treasure just a few degrees away from the bright stars in Orion's belt. NGC 1788 is a reflection nebula, whose gas and dust scatter the light coming from a small cluster of young stars in such a way that the tenuous glow forms a shape reminiscent of a gigantic bat spreading its wings. Very few of the stars belonging to the nebula are visible in this image, as most of them are obscured by the dusty cocoons surrounding them. The most prominent, named HD 293815, can be distinguished as the bright star in the upper part of the cloud, just above the centre of the image and the pronounced dark lane of dust extending through the nebula. Although NGC 1788 appears at first glance to be an isolated cloud, observations covering a field beyond the one presented in this image have revealed that bright, massive stars, belonging to the vast stellar groupings in Orion, have played a decisive role in shaping NGC 1788 and stimulating the formation of its stars. They are also responsible for setting the hydrogen gas ablaze in the parts of the nebula facing Orion, leading to the red, almost vertical rim visible in the left half of the image. All the stars in this region are extremely young, with an average age of only a million years, a blink of an eye compared to the Sun's age of 4.5 billion years. Analysing them in detail, astronomers have discovered that these "preschool" stars fall naturally into three well separated classes: the slightly older ones, located on the left side of the red rim, the fairly young ones, to its right, making up the small cluster enclosed in the nebula and illuminating it, and eventually the very youngest stars, still deeply embedded in their nascent dusty cocoons, further to the right. Although none of the latter are visible in this image because of the obscuring dust, dozens of them have been revealed through observations in the infrared and millimetre wavelengths of light. This fine distribution of stars, with the older ones closer to Orion and the younger ones concentrated on the opposite side, suggests that a wave of star formation, generated around the hot and massive stars in Orion, propagated throughout NGC 1788 and beyond. This image has been obtained using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the

  20. Light Dawns on Dark Gamma-ray Bursts

    NASA Astrophysics Data System (ADS)

    2010-12-01

    Gamma-ray bursts are among the most energetic events in the Universe, but some appear curiously faint in visible light. The biggest study to date of these so-called dark gamma-ray bursts, using the GROND instrument on the 2.2-metre MPG/ESO telescope at La Silla in Chile, has found that these gigantic explosions don't require exotic explanations. Their faintness is now fully explained by a combination of causes, the most important of which is the presence of dust between the Earth and the explosion. Gamma-ray bursts (GRBs), fleeting events that last from less than a second to several minutes, are detected by orbiting observatories that can pick up their high energy radiation. Thirteen years ago, however, astronomers discovered a longer-lasting stream of less energetic radiation coming from these violent outbursts, which can last for weeks or even years after the initial explosion. Astronomers call this the burst's afterglow. While all gamma-ray bursts [1] have afterglows that give off X-rays, only about half of them were found to give off visible light, with the rest remaining mysteriously dark. Some astronomers suspected that these dark afterglows could be examples of a whole new class of gamma-ray bursts, while others thought that they might all be at very great distances. Previous studies had suggested that obscuring dust between the burst and us might also explain why they were so dim. "Studying afterglows is vital to further our understanding of the objects that become gamma-ray bursts and what they tell us about star formation in the early Universe," says the study's lead author Jochen Greiner from the Max-Planck Institute for Extraterrestrial Physics in Garching bei Mnchen, Germany. NASA launched the Swift satellite at the end of 2004. From its orbit above the Earth's atmosphere it can detect gamma-ray bursts and immediately relay their positions to other observatories so that the afterglows could be studied. In the new study, astronomers combined Swift data with new observations made using GROND [2] - a dedicated gamma-ray burst follow-up observation instrument, which is attached to the 2.2-metre MPG/ESO telescope at La Silla in Chile. In doing so, astronomers have conclusively solved the puzzle of the missing optical afterglow. What makes GROND exciting for the study of afterglows is its very fast response time - it can observe a burst within minutes of an alert coming from Swift using a special system called the Rapid Response Mode - and its ability to observe simultaneously through seven filters covering both the visible and near-infrared parts of the spectrum. By combining GROND data taken through these seven filters with Swift observations, astronomers were able to accurately determine the amount of light emitted by the afterglow at widely differing wavelengths, all the way from high energy X-rays to the near-infrared. The astronomers used this information to directly measure the amount of obscuring dust that the light passed through en route to Earth. Previously, astronomers had to rely on rough estimates of the dust content [3]. The team used a range of data, including their own measurements from GROND, in addition to observations made by other large telescopes including the ESO Very Large Telescope, to estimate the distances to nearly all of the bursts in their sample. While they found that a significant proportion of bursts are dimmed to about 60-80 percent of the original intensity by obscuring dust, this effect is exaggerated for the very distant bursts, letting the observer see only 30-50 percent of the light [4]. The astronomers conclude that most dark gamma-ray bursts are therefore simply those that have had their small amount of visible light completely stripped away before it reaches us. "Compared to many instruments on large telescopes, GROND is a low cost and relatively simple instrument, yet it has been able to conclusively resolve the mystery surrounding dark gamma-ray bursts," says Greiner. Notes [1] Gamma-ray bursts lasting longer than two seconds are referred to as long

  1. The Light and Dark Face of a Star-Forming Nebula

    NASA Astrophysics Data System (ADS)

    2010-03-01

    Today, ESO is unveiling an image of the little known Gum 19, a faint nebula that, in the infrared, appears dark on one half and bright on the other. On one side hot hydrogen gas is illuminated by a supergiant blue star called V391 Velorum. New star formation is taking place within the ribbon of luminous and dark material that brackets V391 Velorum's left in this perspective. After many millennia, these fledgling stars, coupled with the explosive demise of V391 Velorum as a supernova, will likely alter Gum 19's present Janus-like appearance. Gum 19 is located in the direction of the constellation Vela (the Sail) at a distance of approximately 22 000 light years. The Gum 19 moniker derives from a 1955 publication by the Australian astrophysicist Colin S. Gum that served as the first significant survey of so-called HII (read "H-two") regions in the southern sky. HII refers to hydrogen gas that is ionised, or energised to the extent that the hydrogen atoms lose their electrons. Such regions emit light at well-defined wavelengths (or colours), thereby giving these cosmic clouds their characteristic glow. And indeed, much like terrestrial clouds, the shapes and textures of these HII regions change as time passes, though over the course of eons rather than before our eyes. For now, Gum 19 has somewhat of a science fiction-esque, "rip in spacetime" look to it in this image, with a narrow, near-vertical bright region slashing across the nebula. Looking at it, you could possibly see a resemblance to a two-toned angelfish or an arrow with a darkened point. This new image of the evocative Gum 19 object was captured by an infrared instrument called SOFI, mounted on ESO's New Technology Telescope (NTT) that operates at the La Silla Observatory in Chile. SOFI stands for Son of ISAAC, after the "father" instrument, ISAAC, that is located at ESO's Very Large Telescope observatory at Paranal to the north of La Silla. Observing this nebula in the infrared allows astronomers to see through at least parts of the dust. The furnace that fuels Gum 19's luminosity is a gigantic, superhot star called V391 Velorum. Shining brightest in the scorching blue range of visible light, V391 Velorum boasts a surface temperature in the vicinity of 30 000 degrees Celsius. This massive star has a temperamental nature, however, and is categorised as a variable star accordingly. V391 Velorum's brightness can fluctuate suddenly as a result of strong activity that can include ejections of shells of matter, which contribute to Gum 19's composition and light emissions. Stars on the grand scale of V391 Velorum do not burn bright for long, and after a relatively short lifetime of about ten million years these titans blow up as supernovae. These explosions, which temporarily rival whole galaxies in their light intensity, blast heated matter in surrounding space, an event that can radically change the colour and shape of its enclosing nebula. As such, V391 Velorum's death throes may well leave Gum 19 unrecognisable. Within the neighbourhood of this fitful supergiant, new stars nonetheless continue to grow. HII regions denote sites of active star formation wherein great quantities of gas and dust have begun to collapse under their own gravity. In several million years - a blink of an eye in cosmic time - these shrinking knots of matter will eventually reach the high density at their centres necessary to ignite nuclear fusion. The fresh outpouring of energy and stellar winds from these newborn stars will also modify the gaseous landscape of Gum 19. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facil

  2. A Glimpse of the Young Milky Way

    NASA Astrophysics Data System (ADS)

    2002-10-01

    VLT UVES Observes Most Metal-Deficient Star Known [1] Summary A faint star in the southern Milky Way, designated HE 0107-5240 , has been found to consist virtually only of hydrogen and helium . It has the lowest abundance of heavier elements ever observed , only 1/200,000 of that of the Sun - 20 times less than the previous record-holding star. This is the result of a major ongoing research project by an international team of astronomers [2]. It is based on a decade-long survey of the southern sky, with detailed follow-up observations by means of the powerful UV-Visual Echelle Spectrograph (UVES) on the 8.2-m VLT KUEYEN telescope at the ESO Paranal Observatory in Chile. This significant discovery now opens a new window towards the early times when the Milky Way galaxy was young, possibly still in the stage of formation. It proves that, contrary to most current theories, comparatively light stars like HE 0107-5240 (with 80% of the mass of the Sun) may form in environments (nearly) devoid of heavier elements. Since some years, astronomers have been desperately searching for stars of the very first stellar generation in the Milky Way, consisting only of hydrogen and helium from the Big Bang. None have been detected so far and doubts have arisen that they exist at all. The present discovery provides new hope that it will ultimately be possible to find such stellar relics from the young Universe and thereby to study "unpolluted" Big Bang material. PR Photo 25a/02 : The sky region around the very metal-deficient star HE 0107-5240 . PR Photo 25b/02 : Comparison of UVES spectra of stars with different metal abundances. Stellar generations in the Milky Way galaxy The Milky Way galaxy in which we live formed from a gigantic cloud of gas, when the Universe was still young, soon after the initial Big Bang. At the beginning, this gas was presumably composed almost exclusively of hydrogen and helium atoms produced during the Big Bang. However, once the first stars formed by contraction in that gas, many heavier elements were built up by nuclear processes in their interiors. As time passed, many of the stars of this and following stellar generations returned the processed matter to their surroundings at the ends of their lives, either during violent supernova explosions or via strong "stellar winds". In this way, the interstellar gas in the Milky Way system has ever since been continuously enriched with heavier elements. Stars of later generations like our Sun now contain those elements produced by their ancestors and we are indeed ourselves made up of them. Consequently, the early (and hence, old) stars in the Milky Way mainly differ from younger stars by containing very small amounts of such elements . Hunting the earliest stars Have some of those earliest stars survived to our days? In theory, at least, it would be possible that some of the lighter ones - having the longest lifetimes - are still around. But if so, where are they? During the past three decades, astronomers have desperately tried to find bona-fide representatives of the very first stellar generation(s) in the Milky Way, i.e. stars with no or, at most, extremely low abundance of elements other than hydrogen and helium. The researchers usually refer to such objects as Population III stars , the other two populations being stars with heavy-element abundances like the Sun (Population I) or somewhat less (Population II) [3]. The Hamburg/ESO survey Now, a group of astronomers from Germany, Sweden, Australia, Brazil and the USA [2] has found a giant star that has a concentration of heavy elements 200,000 times lower than the Sun, or about 20 times less than the previous "record" for this kind of star. It thus provides the researchers with a unique window towards the early stages of the formation of the Milky Way and a fine opportunity to study stellar gas with a composition close to that produced during the Big Bang. This is one important outcome of a systematic search for the most metal-deficient stars that is currently being carried out at Ham

  3. VLT Data Flow System Begins Operation

    NASA Astrophysics Data System (ADS)

    1999-06-01

    Building a Terabyte Archive at the ESO Headquarters The ESO Very Large Telescope (VLT) is the sum of many sophisticated parts. The site at Cerro Paranal in the dry Atacama desert in Northern Chile is one of the best locations for astronomical observations from the surface of the Earth. Each of the four 8.2-m telescopes is a technological marvel with self-adjusting optics placed in a gigantic mechanical structure of the utmost precision, continuously controlled by advanced soft- and hardware. A multitude of extremely complex instruments with sensitive detectors capture the faint light from distant objects in the Universe and record the digital data fast and efficiently as images and spectra, with a minimum of induced noise. And now the next crucial link in this chain is in place. A few nights ago, following an extended test period, the VLT Data Flow System began providing the astronomers with a steady stream of high-quality, calibrated image and spectral data, ready to be interpreted. The VLT project has entered into a new phase with a larger degree of automation. Indeed, the first 8.2-m Unit Telescope, ANTU, with the FORS1 and ISAAC instruments, has now become a true astronomy machine . A smooth flow of data through the entire system ESO PR Photo 25a/99 ESO PR Photo 25a/99 [Preview - JPEG: 400 x 292 pix - 104k] [Normal - JPEG: 800 x 584 pix - 264k] [High-Res - JPEG: 3000 x 2189 pix - 1.5M] Caption to ESO PR Photo 25a/99 : Simplified flow diagramme for the VLT Data Flow System . It is a closed-loop software system which incorporates various subsystems that track the flow of data all the way from the submission of proposals to storage of the acquired data in the VLT Science Archive Facility. The DFS main components are: Program Handling, Observation Handling, Telescope Control System, Science Archive, Pipeline and Quality Control. Arrows indicate lines of feedback. Already from the start of this project more than ten years ago, the ESO Very Large Telescope was conceived as a complex digital facility to explore the Universe. In order for astronomers to be able to use this marvellous research tool in the most efficient manner possible, the VLT computer software and hardware systems must guarantee a smooth flow of scientific information through the entire system. This process starts when the astronomers submit well-considered proposals for observing time and it ends with large volumes of valuable astronomical data being distributed to the international astronomical community. For this, ESO has produced an integrated collection of software and hardware, known as the VLT Data Flow System (DFS) , that manages and facilitates the flow of scientific information within the VLT Observatory. Early information about this new concept was published as ESO Press Release 12/96 and extensive tests were first carried out at ESOs 3.5-m New Technology Telescope (NTT) at La Silla, cf. ESO Press Release 03/97 [1]. The VLT DFS is a complete (end-to-end) system that guarantees the highest data quality by optimization of the observing process and repeated checks that identify and eliminate any problems. It also introduces automatic calibration of the data, i.e. the removal of external effects introduced by the atmospheric conditions at the time of the observations, as well as the momentary state of the telescope and the instruments. From Proposals to Observations In order to obtain observing time with ESO telescopes, also with the VLT, astronomers must submit a detailed observing proposal to the ESO Observing Programmes Committee (OPC) . It meets twice a year and ranks the proposals according to scientific merit. More than 1000 proposals are submitted each year, mostly by astronomers from the ESO members states and Chile; the competition is fierce and only a fraction of the total demand for observing time can be fulfilled. During the submission of observing proposals, DFS software tools available over the World Wide Web enable the astronomers to simulate their proposed observations and provide accurate estimates of the amount of telescope time the