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Sample records for azul formation ediacaran

  1. Acritarchs of the Ediacaran Frecheirinha Formation, Ubajara Group, Northeastern Brazil

    Leticia Chiglino

    2015-06-01

    Full Text Available We report for the first time the occurrence of organic-walled microfossils in Ediacaran limestones and marls of the Frecheirinha Formation, Ubajara Group, and the first Precambrian acritarchs so far reported for northeastern Brazil. The assemblage of the Frecheirinha Formation represents a low-diversity microflora comprising Leiosphaeridia, Lophosphaeridium and subordinated Bavlinella (=Sphaerocongregus. Their thermal alteration index (TAI between 4+ and 5, suggests metamorphic temperatures exceeding 200-250°C. Higher temperatures are probably related to intruding granitic plutons (Meruoca, Mucambo. Reported δ13C values of carbonates of -3.5 ‰ VPDB (Vienna-Peedee Belemnite at the base, passing up section into a positive plateau of up to +3.7 ‰, and corresponding 87Sr/86Sr values between 0.7075 and 0.7080 suggest an Ediacaran age. The acritarch assemblage is comparable to the Late Ediacaran Leiosphere Palynoflora (LELP or Kotlin-Rovno assemblage, in broad agreement with chemostratigraphic data. Macrofossils belonging to the Ediacara fauna were reported from the overlying Jaibaras Group, which would constrain even further the depositional age of the Frecheirinha Formation to within ca. 575-555 Ma. A more comprehensive palynological study of the Frecheirinha Formation is necessary to confirm this age assignment.

  2. Ediacaran Redox Fluctuations

    Sahoo, S. K.; Jiang, G.; Planavsky, N. J.; Kendall, B.; Owens, J. D.; Anbar, A. D.; Lyons, T. W.

    2013-12-01

    Evidence for pervasive oxic conditions, and likely even deep ocean oxygenation has been documented at three intervals in the lower (ca. 632 Ma), middle (ca. 580 Ma) and upper (ca. 551 Ma) Ediacaran. The Doushantuo Formation in South China hosts large enrichments of redox-sensitive trace element (e.g., molybdenum, vanadium and uranium) in anoxic shales, which are indicative of a globally oxic ocean-atmosphere system. However, ocean redox conditions between these periods continue to be a topic of debate and remain elusive. We have found evidence for widespread anoxic conditions through much of the Ediacaran in the deep-water Wuhe section in South China. During most of the Ediacaran-early Cambrian in basinal sections is characterized by Fe speciation data and pyrite morphologies that indicate deposition under euxinic conditions with near-crustal enrichments of redox-sensitive element and positive pyrite-sulfur isotope values, which suggest low levels of marine sulfate and widespread euxinia. Our work reinforces an emerging view that the early Earth, including the Ediacaran, underwent numerous rises and falls in surface oxidation state, rather than a unidirectional rise as originally imagined. The Ediacaran ocean thus experienced repetitive expansion and contraction of marine chalcophilic trace-metal levels that may have had fundamental impact on the slow evolution of early animals and ecosystems. Further, this framework forces us to re-examine the relationship between Neoproterozoic oxygenation and metazoan diversification. Varying redox conditions through the Cryogenian and Ediacaran may help explain molecular clock and biomarker evidence for an early appearance and initial diversification of metazoans but with a delay in the appearance of most major metazoan crown groups until close to Ediacaran-Cambrian boundary.

  3. variedad azul

    R. I. Corona González

    2005-01-01

    Full Text Available En este trabajo se muestra un estudio del efecto del pH, la temperatura y la concentración de polifructosas de Agave tequilana weber variedad azul sobre la producción de inulinasas, con una cepa de Saccharomyces sp. en un reactor de 16 litros. Las condiciones óptimas del proceso se obtuvieron al aplicar un diseño factorial 23 en el cual temperatura, pH y concentración de azúcares de Agave tequilana se probaron con dos niveles 15 y 30°C, 4 y 5.5 y 20 y 30 g/L respectivamente. Las condiciones con las que se alcanzó la concentración más alta de inulinasas (240.6 U/ml fueron: temperatura 30°C, pH 5.5 y 30 g/L de polifructosas de Agave tequilana

  4. Is Absence of Evidence of UHPM Evidence of Absence: Did Conditions on Earth Before the Ediacaran Period Allow Formation of UHP Rocks but Only Rarely Their Exhumation?

    Brown, M.

    2008-12-01

    UHPM provides petrologic evidence of transport of continental lithosphere to asthenospheric depth and return of some of these materials to crustal depth. The rock record registers UHPM since the Ediacaran Period, and studies of inclusion assemblages in zircon have increased the evidence of UHPM in Phanerozoic orogens and enabled an assessment of the real estate involved. Plots of apparent thermal gradient vs. age of metamorphism and P vs. age of metamorphism reveal two dramatic changes in inferred thermal environment and inferred depth of metamorphism from which continental lithosphere has been recovered during Earth evolution. First, from the Mesoarchean Era to the Neoproterozoic Era, sutures in subduction-to- collision orogens are marked by eclogite and high-pressure granulite metamorphism (characterized by apparent thermal gradients of 750-350 C/GPa). The P of metamorphism in sutures jumped from the Eoarchean-Paleoarchean up to 2 GPa during the Paleoproterozoic. Second, from the Cryogenian- Ediacaran to the present, many sutures in subduction-to-collision orogens, and sometimes intracratonic sutures in the overriding plate, are marked by UHPM (characterized by apparent thermal gradients of 2.7GPa. Given this pattern of secular change to colder apparent thermal gradients in sutures, the recent discovery of diamonds in zircons of crustal paragenesis in Neoarchean sedimentary rocks is surprising. Maybe UHPM has been possible since the Neoarchean but the evidence was rarely exhumed or if exhumed maybe the evidence was rarely preserved? The Appalachian/Caledonian-Variscide-Altaid and the Cimmerian-Himalayan-Alpine orogenic systems were formed by successive closure of short-lived oceans by transfer and suturing of ribbon-continent terranes derived from the Gondwanan side. Subduction of young ocean lithosphere followed by choking of the subduction channel by arc or terrane collision limited transport of water to the mantle wedge, and suppressed development of small

  5. Integrated carbon, sulfur, and nitrogen isotope chemostratigraphy of the Ediacaran Lantian Formation in South China: Spatial gradient, ocean redox oscillation, and fossil distribution.

    Wang, W; Guan, C; Zhou, C; Peng, Y; Pratt, L M; Chen, X; Chen, L; Chen, Z; Yuan, X; Xiao, S

    2017-07-01

    The Ediacaran Doushantuo Formation in South China is a prime target for geobiological investigation because it offers opportunities to integrate chemostratigraphic and paleobiological data. Previous studies were mostly focused on successions in shallow-water shelf facies, but data from deep-water successions are needed to fully understand basinal redox structures. Here, we report δ 13 C carb , δ 13 C org , δ 34 S pyr , δ 34 S CAS , and δ 15 N sed data from a drill core of the fossiliferous Lantian Formation, which is a deep-water equivalent of the Doushantuo Formation. Our data confirm a large (>10‰) spatial gradient in δ 13 C carb in the lower Doushantuo/Lantian formations, but this gradient is probably due to the greater sensitivity of carbonate-poor deep-water sediments to isotopic mixing with 13 C-depleted carbonate cements. A pronounced negative δ 13 C carb excursion (EN3) in the upper Doushantuo/Lantian formations, however, is spatially consistent and may be an equivalent of the Shuram excursion. δ 34 S pyr is more negative in deeper-water facies than in shallow-water facies, particularly in the lower Doushantuo/Lantian formations, and this spatial pattern is interpreted as evidence for ocean redox stratification: Pyrite precipitated in euxinic deep waters has lower δ 34 S pyr than that formed within shallow-water sediments. The Lantian Formation was probably deposited in oscillating oxic and euxinic conditions. Euxinic black shales have higher TOC and TN contents, but lower δ 34 S pyr and δ 15 N sed values. In euxinic environments, pyrite was predominantly formed in the water column and organic nitrogen was predominantly derived from nitrogen fixation or NH 4 + assimilation because of quantitative denitrification, resulting in lower δ 34 S pyr and δ 15 N sed values. Benthic macroalgae and putative animals occur exclusively in euxinic black shales. If preserved in situ, these organisms must have lived in brief oxic episodes punctuating largely

  6. A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link

    Smith, E. F.; Nelson, L. L.; Tweedt, S. M.; Zeng, H.; Workman, Jeremiah B.

    2017-01-01

    Owing to the lack of temporally well-constrained Ediacaran fossil localities containing overlapping biotic assemblages, it has remained uncertain if the latest Ediacaran (ca 550–541 Ma) assemblages reflect systematic biological turnover or environmental, taphonomic or biogeographic biases. Here, we report new latest Ediacaran fossil discoveries from the lower member of the Wood Canyon Formation in Nye County, Nevada, including the first figured reports of erniettomorphs, Gaojiashania, Conotubus and other problematic fossils. The fossils are spectacularly preserved in three taphonomic windows and occur in greater than 11 stratigraphic horizons, all of which are below the first appearance of Treptichnus pedum and the nadir of a large negative δ13C excursion that is a chemostratigraphic marker of the Ediacaran–Cambrian boundary. The co-occurrence of morphologically diverse tubular fossils and erniettomorphs in Nevada provides a biostratigraphic link among latest Ediacaran fossil localities globally. Integrated with a new report of Gaojiashania from Namibia, previous fossil reports and existing age constraints, these finds demonstrate a distinctive late Ediacaran fossil assemblage comprising at least two groups of macroscopic organisms with dissimilar body plans that ecologically and temporally overlapped for at least 6 Myr at the close of the Ediacaran Period. This cosmopolitan biotic assemblage disappeared from the fossil record at the end of the Ediacaran Period, prior to the Cambrian radiation.

  7. Redox history of the Three Gorges region during the Ediacaran and Early Cambrian as indicated by the Fe isotope

    Yusuke Sawaki

    2018-01-01

    To circumvent this deficiency, we drilled a fossiliferous Ediacaran to Early Cambrian sedimentary succession in the Three Gorges region, South China. We analyzed the iron isotope ratios (δ56/54Fe of pyrite grains in the drill cores using laser ablation multi collector inductively coupled plasma mass spectrometry. The results demonstrate large variations in δ56/54Fe, from −1.6 to 1.6‰, and positive iron isotope ratios are observed in many successions. The presence of positive δ56/54Fe in pyrite indicates that the ferrous iron in the seawater was partially oxidized, suggesting that seawater at Three Gorges was ferruginous during the Ediacaran and Early Cambrian periods. However, aggregated pyrite grains in organic carbon-rich black shales at Member 4 of the Doushantuo Formation and the base of the Shuijingtuo Formation yield near-zero δ56/54Fe values; this suggests that the ocean was transiently dominated by sulfidic conditions during these periods. Notably negative δ56/54Fe values, lower than −1‰, can be interpreted as a signature of DIR. The DIR also might contribute in part to the re-mineralization of organic matter during the largest negative carbon isotope anomaly in the Ediacaran.

  8. Identification of multiple magnetizations of the Ediacaran strata in South China

    Jing, Xianqing; Yang, Zhenyu; Tong, Yabo; Wang, Heng; Xu, Yingchao

    2018-01-01

    multiple generations of oil and gas in the Ediacaran and Cambrian strata are suggested as the main mechanism for remagnetization. Despite the pervasive Silurian remagnetization of the Ediacaran strata, most of the HTC from the thick-bedded dolostone of Doushantuo Formation Member 3 at the JLWS section appears to carry a primary remanence, because its pole differs from other poles of South China and the results pass both the fold and reversal tests. The relatively low-geothermic conditions and the absence of both hydrocarbon and smectite/illite explain why most results from the Doushantuo Member 3 of JLWS section were not affected by the Silurian remagnetization. This new Ediacaran pole supersedes the previous suspected remagnetized poles, which can be used to constrain the palaeoposition of South China both in Rodinia and Gondwana.

  9. Late Ediacaran magnetostratigraphy of Baltica: Evidence for Magnetic Field Hyperactivity?

    Bazhenov, Mikhail L.; Levashova, Natalia M.; Meert, Joseph G.; Golovanova, Inessa V.; Danukalov, Konstantin N.; Fedorova, Natalia M.

    2016-02-01

    Long-term changes in characteristics of the geomagnetic field may signal evolutionary changes within the Earth's interior. Among these long-term variations, the magnetic field reversal rate is probably the best known and most frequently used parameter to evaluate concomitant changes in the Earth's core. Although the reversal rate is well known for the last 150 Ma and reasonably constrained back to 300 Ma, knowledge of the early Paleozoic and earlier times is limited. Hence, the haunting question is whether the reversal pattern for the last 300 Myr is a good representation of the field behavior over a much longer interval. A paleomagnetic study of Upper Ediacaran sediments from the Zigan Fm. (Baltica in the western South Urals) revealed a high-temperature, dual-polarity component that is of primary origin (Levashova et al., 2013). In this paper, we present the results of a magnetostratigraphic study from the same sections that can be summed up as follows: 1) >30 magnetozones are found in the ca. 110 meters thick composite section of the Zigan Fm.; 2) A similar reversal pattern was reported from Upper Ediacaran sediments from the White Sea coast (North Russia) and SW Siberia but has never been found in clastic rocks of any other age; 3) The reversal pattern in three remote Ediacaran sections could not result from remagnetization or extremely slow sedimentation; 4) The reversal rate in the Late Ediacaran exceeded 20 reversals per million years; 5) The field appears to behave in a bipolar fashion during the period of hyperactivity.

  10. Evolution of oceanic molybdenum and uranium reservoir size around the Ediacaran-Cambrian transition: Evidence from western Zhejiang, South China

    Xiang, Lei; Schoepfer, Shane D.; Shen, Shu-zhong; Cao, Chang-qun; Zhang, Hua

    2017-04-01

    The "Cambrian explosion" is one of the most fascinating episodes of diversification in the history of life; however, its relationship to the oxygenation of the oceans and atmosphere around the Ediacaran-Cambrian transition is not fully understood. Marine inventories of redox-sensitive trace elements reflect the relative balance of oxidative weathering on land and deposition in anoxic water masses, and can be used to explore the evolution of oceanic and atmospheric redox conditions. For this study, we conducted a series of geochemical analyses on the upper Lantian, Piyuancun, and Hetang formations in the Chunye-1 well, part of the lower Yangtze Block in western Zhejiang. Iron speciation results indicate that the entire studied interval was deposited under anoxic conditions, with three intervals of persistent euxinia occurring in the uppermost Lantian Fm., the lower Hetang Formation (Fm.), and the upper Hetang Fm. Molybdenum (Mo) and uranium (U) contents and Mo/TOC and U/TOC ratios from the anoxic/euxinic intervals of the Chunye-1 well, combined with published data from the sections in the middle and upper Yangtze Block, suggest that the oceanic Mo reservoir declined consistently from the Ediacaran to Cambrian Stage 3, while the size of the oceanic U reservoir remained relatively constant. Both metals were depleted in the ocean in lower Cambrian Stage 4, before increasing markedly at the end of Stage 4. The lack of an apparent increase in the size of the marine Mo and U reservoir from the upper Ediacaran to Cambrian Stage 3 suggests that oxic water masses did not expand until Cambrian Stage 4. The increase in marine Mo and U availability in the upper Hetang Fm. may have been due to the expansion of oxic water masses in the oceans, associated with oxygenation of the atmosphere during Cambrian Stage 4. This expansion of oxic waters in the global ocean postdates the main phase of Cambrian diversification, suggesting that pervasive oxygenation of the ocean on a large

  11. Paleomagnetic evidence of a Late ediacaran ocean in South America?

    Rapalini, A.; Sanchez Bettucci, L.; Tohver, E.

    2016-01-01

    In recent years, a controversy arose on whether a large ocean, called Cymene, existed between the Amazon ian craton and the Rio de la Plata / Congo-Sao Francisco craton s in the late Ediacaran. Comparison of the available reliable Paleomagnetic poles from the latter two craton s, West Africa and Lauren tia for the interval 615-560 Ma suggests that by ca. 575 Ma a large ocean existed between Lauren tia-Amazon ia-West Africa on one side and Río de la Plata and Congo-Sao Francisco on the other. This conclusion is still valid whether the “high latitude” or the “low latitude” option is chosen for Lauren tia. However, Paleomagnetic data from the proper Amazon ia are needed for definite conclusions

  12. Ecological interactions in Cloudina from the Ediacaran of Brazil: implications for the rise of animal biomineralization.

    Becker-Kerber, Bruno; Pacheco, Mírian Liza Alves Forancelli; Rudnitzki, Isaac Daniel; Galante, Douglas; Rodrigues, Fabio; Leme, Juliana de Moraes

    2017-07-14

    At the Ediacaran/Cambrian boundary, ecosystems witnessed an unparalleled biological innovation: the appearance of shelled animals. Here, we report new paleoecological and paleobiological data on Cloudina, which was one of the most abundant shelled animals at the end of the Ediacaran. We report the close association of Cloudina tubes with microbial mat textures as well as organic-rich material, syndepositional calcite and goethite cement between their flanges, thus reinforcing the awareness of metazoan/microorganism interactions at the end of the Ediacaran. The preservation of in situ tubes suggests a great plasticity of substrate utilization, with evidence of different life modes and avoidance behavior. Geochemical analysis revealed walls composed of two secondary laminae and organic sheets. Some walls presented boreholes that are here described as predation marks. Taken together, these data add further information regarding the structuring of shelled animal communities in marine ecosystems.

  13. New geochemical, geochronological and structural constraints on the Ediacaran evolution of the south Sirwa, Agadir-Melloul and Iguerda inliers, Anti-Atlas, Morocco

    Blein, O.; Baudin, T.; Soulaimani, A.; Cocherie, A.; Chèvremont, P.; Admou, H.; Ouanaimi, H.; Hafid, A.; Razin, P.; Bouabdelli, M.; Roger, J.

    2014-10-01

    Paleoproterozoic metamorphic and igneous rocks, Tonian (?)-lower Cryogenian passive margin sedimentary rocks, Neoproterozoic dolerites, and Upper Ediacaran volcaniclastic, volcanic and pyroclastic rocks are exposed in the Agadir Melloul, Iguerda and the southern edge of the Sirwa inliers. A recent field mapping program of the Ediacaran Ouarzazate Group in these areas allow to distinguish three principal volcanic sequences. The first sequence (Adrar-n-Takoucht Formation) outcrops mainly south of the Sirwa inlier, and is composed of felsic pyroclastic deposits and local basaltic lavas with ages ranging between 572 and 570 Ma. The second sequence (Anammar and Tadoughast formations) occurs primarily in the Agadir Melloul-Jbel Iguiguil inlier. The Anammar Formation contains essentially volcano-detrital sediments, with fine airfall pyroclastic deposits. The Tadoughast Formation is composed of felsic pyroclastic deposits and rhyolitic domes with ages ranging between 567 and 564 Ma. The third sequence (Fajjoud Formation) contains felsic pyroclastic deposits, with an age of 556 Ma, associated with porphyritic basalts. The magmatism of the Ouarzazate Group was not continuous between 572 and 556 Ma, but related to distinct pyroclastic pulses. Geochemical data indicate that the pyroclastic rocks of the Ouarzazate Group have a highly potassic calc-alkaline to shoshonitic affinity. However, the basaltic facies associated with the Adrar-n-Takoucht Formation demonstrate a calc-alkaline affinity whereas those associated with the Fajjoud Formation have a tholeiitic affinity. Rhyolitic domes were derived from hyperaluminous leucogranites. In sum, the typology of zircons defines three poles: (i) subalkaline granites; (ii) calc-alkaline monzogranites and granodiorites frequently associated with basic rocks; and (iii) aluminous leucogranites. In addition, the volcaniclastic deposits of the Ouarzazate Group are submitted to a syn-sedimentary tectonic. The Adrar-n-Takoucht Formation is

  14. Molecular structures of fructans from Agave tequilana Weber var. azul.

    Lopez, Mercedes G; Mancilla-Margalli, Norma A; Mendoza-Diaz, Guillermo

    2003-12-31

    Agave plants utilize crassulacean acid metabolism (CAM) for CO(2) fixation. Fructans are the principal photosynthetic products generated by agave plants. These carbohydrates are fructose-bound polymers frequently with a single glucose moiety. Agave tequilana Weber var. azul is an economically important CAM species not only because it is the sole plant allowed for tequila production but because it is a potential source of prebiotics. Because of the large amounts of carbohydrates in A. tequilana, in this study the molecular structures of its fructans were determined by fructan derivatization for linkage analysis coupled with gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS). Fructans were extracted from 8-year-old A. tequilana plants. The linkage types present in fructans from A. tequilana were determined by permethylation followed by reductive cleavage, acetylation, and finally GC-MS analysis. Analysis of the degree of polymerization (DP) estimated by (1)H NMR integration and (13)C NMR and confirmed by MALDI-TOF-MS showed a wide DP ranging from 3 to 29 units. All of the analyses performed demonstrated that fructans from A. tequilana consist of a complex mixture of fructooligosaccharides containing principally beta(2 --> 1) linkages, but also beta(2 --> 6) and branch moieties were observed. Finally, it can be stated that fructans from A. tequilana Weber var. azul are not an inulin type as previously thought.

  15. Blue toe syndrome Síndrome do dedo azul

    Paulo Eduardo Ocke Reis

    2005-01-01

    Full Text Available The authors report the case of a man with blue toe syndrome, who developed bilateral foot ischemia and underwent successful repair of an abdominal aortic aneurysm and associated renal artery stenosis. Blue toe syndrome is characterized by tissue ischemia secondary to embolization of cholesterol crystals or atherothrombotic debris. Microembolization most often occurs in elderly men who undergo an invasive vascular procedure or have an aneurysm.Os autores relatam o caso de síndrome do dedo azul em um homem que apresentou um quadro de isquemia bilateral dos pés e foi submetido ao reparo bem sucedido de um aneurisma da aorta abdominal e de estenose da artéria renal associada. A síndrome do dedo azul é caracterizada pela isquemia tecidual, secundária à embolização de cristais de colesterol ou aterotrombose. A microembolização ocorre mais freqüentemente em homens idosos que têm um aneurisma ou são submetidos a um procedimento vascular invasivo.

  16. La estrategia del océano azul para emprendedores

    Tula Mendoza Farro

    2013-06-01

    Full Text Available Los emprendedores deben tener presente que no siempre la planeación garantiza el logro de los objetivos, sin embargo sin planes es difícil alcanzar metas (1. Alfred Chandler J. define que “la estrategia es la determinación de los objetivos y planes a largo plazo de la empresa, las acciones a emprender y la asignación de recursos necesarios para lograr esto...” (2. Michael Porter sostiene que “la empresa sin estrategia está dispuesta a intentar cualquier cosa” (3. C.K. Prahalad dice que “si queremos escapar de la atracción gravitacional del pasado tenemos que ser capaces de replantear nuestras propias ortodoxias. Debemos volver a generar nuestras estrategias esenciales y replantear nuestras creencias fundamentales sobre cómo vamos a competir” (4. Peter Drucker, en tanto, considera que “la estrategia de la organización es la respuesta a dos preguntas: ¿qué es nuestro negocio? y ¿qué debería ser?” (5. Las concepciones de estrategia en la empresa son diversas, pero todas coinciden en la enorme trascendencia que tiene para la gestión empresarial. Los modelos de estrategia, del mismo modo esencial para la gestión, también son distintos, pero suelen variar en función de la búsqueda de mejores resultados. Un emergente y expectante modelo es hoy la estrategia del océano azul, que alienta la innovación en la apertura de mercados y deja de lado la competencia como modelo estratégico. La estrategia del océano azul, formulada por W. Chan Kim y Renée Mauborgne en su gran best seller del mismo nombre (6, sostiene que las empresas si quieren ser exitosas pueden hacerlo explorando nuevos mercados, nuevas oportunidades y a través de la innovación en valor (innovación con utilidad, precio y costo, sin preocuparse en la competencia. Es un modelo de “no competencia”, de búsqueda de nuevas oportunidades, de intactos escenarios, de aguas tranquilas e inexploradas que simbolizan el océano azul, y que precisamente es una

  17. Chemostratigraphy of Neoproterozoic Banded Iron Formation (BIF)

    Gaucher, Claudio; Sial, Alcides N.; Frei, Robert

    2015-01-01

    Sawawin BIF (Saudi Arabia), and the Jucurutu Formation of the Seridó Belt (NE Brazil). Lake Superior type BIFs are represented by the Tonian Shilu Group (South China) and the late Ediacaran Arroyo del Soldado Group (Yerbal and Cerro Espuelitas formations, Uruguay). Useful chemostratigraphic tools...

  18. Aberrant meiotic behavior in Agave tequilana Weber var. azul.

    Ruvalcaba-Ruiz, Domingo; Rodríguez-Garay, Benjamin

    2002-10-23

    Agave tequilana Weber var. azul, is the only one variety permitted by federal law in México to be used for tequila production which is the most popular contemporary alcoholic beverage made from agave and recognized worldwide. Despite the economic, genetic, and ornamental value of the plant, it has not been subjected to detailed cytogenetic research, which could lead to a better understanding of its reproduction for future genetic improvement. The objective of this work was to study the meiotic behavior in pollen mother cells and its implications on the pollen viability in Agave tequilana Weber var. azul. The analysis of Pollen Mother Cells in anaphase I (A-I) showed 82.56% of cells with a normal anaphase and, 17.44% with an irregular anaphase. In which 5.28% corresponded to cells with side arm bridges (SAB); 3.68% cells with one bridge and one fragment; 2.58% of irregular anaphase showed cells with one or two lagging chromosomes and 2.95% showed one acentric fragment; cells with two bridges and cells with two bridges and one acentric fragment were observed in frequencies of 1.60% and 1.35% respectively. In anaphase II some cells showed bridges and fragments too. Aberrant A-I cells had many shrunken or empty pollen grains (42.00%) and 58.00 % viable pollen. The observed meiotic irregularities suggest that structural chromosome aberrations have occurred, such as heterozygous inversions, sister chromatid exchanges, deletions and duplications which in turn are reflected in a low pollen viability.

  19. Aberrant meiotic behavior in Agave tequilana Weber var. azul

    Rodríguez-Garay Benjamin

    2002-10-01

    Full Text Available Abstract Background Agave tequilana Weber var. azul, is the only one variety permitted by federal law in México to be used for tequila production which is the most popular contemporary alcoholic beverage made from agave and recognized worldwide. Despite the economic, genetic, and ornamental value of the plant, it has not been subjected to detailed cytogenetic research, which could lead to a better understanding of its reproduction for future genetic improvement. The objective of this work was to study the meiotic behavior in pollen mother cells and its implications on the pollen viability in Agave tequilana Weber var. azul. Results The analysis of Pollen Mother Cells in anaphase I (A-I showed 82.56% of cells with a normal anaphase and, 17.44% with an irregular anaphase. In which 5.28% corresponded to cells with side arm bridges (SAB; 3.68% cells with one bridge and one fragment; 2.58% of irregular anaphase showed cells with one or two lagging chromosomes and 2.95% showed one acentric fragment; cells with two bridges and cells with two bridges and one acentric fragment were observed in frequencies of 1.60% and 1.35% respectively. In anaphase II some cells showed bridges and fragments too. Aberrant A-I cells had many shrunken or empty pollen grains (42.00% and 58.00 % viable pollen. Conclusion The observed meiotic irregularities suggest that structural chromosome aberrations have occurred, such as heterozygous inversions, sister chromatid exchanges, deletions and duplications which in turn are reflected in a low pollen viability.

  20. Thallium isotopes track fluctuations in global manganese oxide burial during the Ediacaran Period

    Ostrander, C. M.; Nielsen, S.; Owens, J. D.; Jiang, G.; Planavsky, N.; Sahoo, S. K.; Zhang, F.; Lyons, T. W.; Anbar, A. D.

    2017-12-01

    Complex marine ecosystems appear in the geologic record for the first time during the Ediacaran (635 - 541 Ma), after the Marinoan Glaciation but before the Cambrian Explosion. Much debate surrounds the redox-state of global oceans during this diversification, with some arguing for pervasive anoxic conditions and others for increased oxygenation, including the possibility of episodic oxygen increases. Here, we use thallium (Tl) isotopes preserved in organic-rich shales from a deep-water section at Wuhe, South China, to track large-scale perturbations in Mn oxide burial during the Ediacaran. Changes to the Tl isotope composition of seawater over geologic timescales are driven dominantly by fluctuations in global Mn oxide burial, which require persistent O2 at the sediment-water interface. Importantly, the suite of sedimentary rocks analyzed is thought to have been deposited beneath persistent localized euxinia, which is an environment shown to effectively capture the Tl isotope composition of seawater. Within samples previously suggested to host oceanic oxygenation episodes (OOEs) because of high redox-sensitive element (RSE) enrichments (Sahoo et al. 2016, Geobiology), we find Tl isotope values as light as -5 epsilon units, which are indicative of removal of heavy Tl by Mn oxides elsewhere in the Ediacaran ocean and in-line with the presence of deep-marine O2. Intriguingly, between these events, during periods previously viewed as dominantly anoxic, we find Tl isotope excursions to values that are even lighter than during the OOEs (less than -10 epsilon units). To first order, these results imply that an even larger Mn oxide sink was present between the OOEs, which would require pervasive oceanic oxygenation. This interpretation is in direct conflict with interpretations of low RSE enrichments in these same samples, which invoke reservoir drawdown due to widespread anoxia—as well as many other data that suggest dominantly anoxic deep marine conditions through the

  1. A geochemical study of the Ediacaran discoidal fossil Aspidella preserved in limestones: Implications for its taphonomy and paleoecology.

    Bykova, N; Gill, B C; Grazhdankin, D; Rogov, V; Xiao, S

    2017-07-01

    The Ediacara biota features the rise of macroscopic complex life immediately before the Cambrian explosion. One of the most abundant and widely distributed elements of the Ediacara biota is the discoidal fossil Aspidella, which is interpreted as a subsurface holdfast possibly anchoring a frondose epibenthic organism. It is a morphologically simple fossil preserved mainly in siliciclastic rocks, which are unsuitable for comprehensive stable isotope geochemical analyses to decipher its taphonomy and paleoecology. In this regard, three-dimensionally preserved Aspidella fossils from upper Ediacaran limestones of the Khatyspyt Formation in the Olenek Uplift of northern Siberia offer a rare opportunity to leverage geochemistry for insights into their taphonomy and paleoecology. To take advantage of this opportunity, we analyzed δ 13 C carb , δ 18 O carb , δ 13 C org , δ 34 S pyr , and iron speciation of the Khatyspyt Aspidella fossils and surrounding sediment matrix in order to investigate whether they hosted microbial symbionts, how they were fossilized, and the redox conditions of their ecological environments. Aspidella holdfasts and surrounding sediment matrix show indistinguishable δ 13 C org values, suggesting they did not host and derive significant amount of nutrients from microbial symbionts such as methanogens, methylotrophs, or sulfide-oxidizing bacteria. δ 13 C carb , δ 18 O carb , and δ 34 S pyr data, along with petrographic observations, suggest that microbial sulfate reduction facilitated the preservation of Aspidella by promoting early authigenic calcite cementation in the holdfasts before matrix cementation and sediment compaction. Iron speciation data are equivocal, largely because of the low total iron concentrations. However, consideration of published sulfur isotope and biomarker data suggests that Aspidella likely lived in non-euxinic waters. It is possible that Aspidella was an opportunistic organism, colonizing the seafloor in large

  2. Pan African Collisional Tectonics Along the Moroccan West African Craton Continued to Ediacaran-Cambrian Boundary

    Hefferan, K. P.; Samson, S. D.; Rice, K.; Soulaimani, A.

    2016-12-01

    Precision geochronologic dating and field mapping in the Anti-Atlas Mountains of Morocco document a Neoproterozoic Pan African orogenic cycle consisting of three distinct orogenic events: Iriri-Tichibanine orogeny (760-700 Ma), Bou Azzer orogeny (680-640 Ma) and the WACadomian orogeny (620 Ma to either 555 or 544 Ma). The Iriri-Tichibanine and Bou Azzer orogenies involved northward directed subduction beneath island arc volcanic terranes. These orogenic events generated calc-alkaline magmatism and supra-subduction zone ophiolites exposed in the Bou Azzer and Siroua erosional inliers. The WACadomian orogeny involved subduction and collision of the Cadomia arc complex with the West African Craton and generation of clastic sedimentary basins. The termination of the WACadomian orogeny has been the subject of debate as calc-alkaline to high K magmatism and folding continued to 544 Ma: Was 620-544 Ma calc-alkaline to high K magmatism and clastic basin development due to a) continental rift basin tectonics or b) southward directed subduction and collisional tectonics with associated back arc basin tectonism? We present field and geochemical data supporting the continuation of subduction-collisional tectonics to the Ediacaran-Cambrian boundary 544 Ma. Field mapping in the Central Anti-Atlas (Agadir Melloul) clearly documents an angular unconformity between Ouarzazate Group and Adoudounian limestones (N 30°31'28.91", W07°48'29.12"). Volcaniclastic rocks of Ouarzazate Group (615-545 Ma) are clearly folded and unconformably overlain by Adoudou Formation (541-529 Ma) limestones to the north. Geochemical discrimination diagrams on Latest Neoproterozoic calc-alkaline to high K igneous rocks throughout the Anti-Atlas plot in subduction and collisional arc magma domains. Back arc basin tectonism is likely responsible for localized extensional basins but continental rift tectonics and passive margin sedimentation did not begin in the Anti-Atlas Mountains until Early

  3. Petrogenesis of the NE Gondwanan uppermost Ediacaran-Lower Cretaceous siliciclastic sequence of Jordan: Provenance, tectonic, and climatic implications

    Amireh, Belal S.

    2018-04-01

    Detrital framework modes of the NE Gondwanan uppermost Ediacaran-Lower Cretaceous siliciclastic sequence of Jordan are determined employing the routine polarized light microscope. The lower part of this sequence constitutes a segment of the vast lower Paleozoic siliciclastic sheet flanking the northern Gondwana margin that was deposited over a regional unconformity truncating the outskirts of the East African orogen in the aftermath of the Neoproterozoic amalgamation of Gondwana. The research aims to evaluate the factors governing the detrital light mineral composition of this sandstone. The provenance terranes of the Arabian craton controlled by plate tectonics appear to be the primary factor in most of the formations, which could be either directly inferred employing Dickinson's compositional triangles or implied utilizing the petrographic data achieved and the available tectonic and geological data. The Arabian-Nubian Shield constitutes invariably the craton interior or the transitional provenance terrane within the NE Gondwana continental block that consistently supplied sandy detritus through northward-flowing braided rivers to all the lower Paleozoic formations. On the other hand, the Lower Cretaceous Series received siliciclastic debris, through braided-meandering rivers having same northward dispersal direction, additionally from the lower Paleozoic and lower-middle Mesozoic platform strata in the Arabian Craton. The formations making about 50% of the siliciclastic sequence represent a success for Dickinson's plate tectonics-provenance approach in attributing the detrital framework components primarily to the plate tectonic setting of the provenance terranes. However, even under this success, the varying effects of the other secondary sedimentological and paleoclimatological factors are important and could be crucial. The inapplicability of this approach to infer the appropriate provenance terranes of the remaining formations could be ascribed either to the

  4. DURABILIDAD DEL CEMENTO PORTLAND BLANCO ADICIONADO CON PIGMENTO AZUL ULTRAMAR

    CAROLINA GIRALDO

    2010-01-01

    Full Text Available El pigmento Azul Ultramar (AU es un aluminosilicato polisulfurado de sodio que reacciona con el aluminato tricálcico (C3A y con el óxido de calcio (CaO del cemento Pórtland blanco en presencia de agua, generando cantidades considerables de etringita a edad temprana y en menor proporción de tobermorita. Esta etringita primaria se presenta en forma de fibras no orientadas mejorando el desempeño mecánico de los morteros, y al mismo tiempo dejando pocas cantidades de C3A disponible para la formación de etringita secundaria. En esta investigación se evalúa la durabilidad a diferentes edades de curado en morteros de cemento Portland blanco sustituidos por 0%, 10% y 20% de AU en peso, mediante pruebas de succión capilar y evaluación del cambio longitudinal de morteros expuestos a una solución de sulfato de sodio con una concentración del 5% (ASTM C1012. Los resultados evidencian una mayor resistencia a compresión y a flexión, una significativa disminución de la expansión y una reducción hasta del 800% de la absorción de agua en morteros con AU. Todo esto debido a la formación de las fases minerales adicionales (etringita primaria y tobermorita, las cuales fueron identificadas mediante microscopía electrónica de barrido (SEM.

  5. El duelo y el tiempo mítico en Rosa Cuchillo y La hora azul

    Torres Oyarce, Tania

    2017-01-01

    En este artículo, sostenemos que las novelas Rosa Cuchillo y La hora azul proyectan procesos individuales de duelo en un orden social mítico que se limita a reproducir el fantasma de la nación cercada (Ubilluz) como (seudo) propuesta de solución al conflicto armado acontecido en el Perú entre 1980-2000. En Rosa Cuchillo, la protagonista Rosa Cuchillo atraviesa un proceso de duelo por haber perdido a su hijo subversivo, Liborio, mientras que, en La hora azul, el protagonista Adrián Ormache suf...

  6. Influence of blue light spectrum filter on short-wavelength and standard automated perimetries Influência de filtro para o espectro azul da luz na perimetria computadorizada branco-branco e azul-amarelo

    Leonardo Cunha Castro

    2006-10-01

    Full Text Available PURPOSE: To evaluate the influence of a blue light spectrum filter (BLSF, similar in light spectrum transmittance to the intraocular lens Acrysof NaturalTM, on standard automated perimetry (SAP and short-wavelength automated perimetry (SWAP. METHODS: Twenty young individuals (OBJETIVO: Avaliar a influência de um filtro para o espectro azul da luz, semelhante à lente intra-ocular Acrysof Natural®, nos exames de perimetria automatizada padrão (branco-no-branco e de comprimento de onda curto (azul-no-amarelo. MÉTODOS: Vinte pacientes jovens sem alterações oculares (20 olhos realizaram seqüência de 4 exames de campo visual: perimetria automatizada padrão e azul-no-amarelo com e sem o filtro para o espectro azul da luz. Os índices de limiar foveal (FT, desvio médio (MD e desvio-padrão (PSD obtidos em todos os exames e a diferença causada pela excentricidade nos exames de perimetria automatizada azul-no-amarelo foram analisados. Variabilidade interindivíduos (desvio-padrão dos pontos testados foi calculada. RESULTADOS: Observou-se redução estatisticamente significante no desvio médio (p<0.001 e no limiar foveal (p<0.001 medidos pela perimetria automatizada azul-no-amarelo com o uso do filtro para o espectro azul da luz comparado quando realizado sem o filtro. Nenhum outro índice avaliado apresentou diferença estatisticamente significante nos exames de perimetria automatizada padrão ou azul-no-amarelo. Foi notado aumento da variabilidade interindivíduos com a excentricidade nos exames de perimetria automatizada azul-no-amarelo com e sem o uso do filtro para o espectro azul da luz, assim como a diferença de sensibilidade entre os hemisférios inferior e superior (hemisfério inferior menos superior, mas não houve diferença estatisticamente significante quando comparados os exames com e sem o uso do filtro. Quando foram comparados os 4 pontos mais inferiores e os 4 pontos mais superiores, a diferença inferior-superior aumentou

  7. Penetrative trace fossils from the late Ediacaran of Mongolia: early onset of the agronomic revolution

    Oji, Tatsuo; Dornbos, Stephen Q.; Yada, Keigo; Hasegawa, Hitoshi; Gonchigdorj, Sersmaa; Mochizuki, Takafumi; Takayanagi, Hideko; Iryu, Yasufumi

    2018-02-01

    The Cambrian radiation of complex animals includes a dramatic increase in the depth and intensity of bioturbation in seafloor sediment known as the `agronomic revolution'. This bioturbation transition was coupled with a shift in dominant trace fossil style from horizontal surficial traces in the late Precambrian to vertically penetrative trace fossils in the Cambrian. Here we show the existence of the first vertically penetrative trace fossils from the latest Ediacaran: dense occurrences of the U-shaped trace fossil Arenicolites from late Precambrian marine carbonates of Western Mongolia. Their Ediacaran age is established through stable carbon isotope chemostratigraphy and their occurrence stratigraphically below the first appearance of the trace fossil Treptichnus pedum. These Arenicolites are large in diameter, penetrate down to at least 4 cm into the sediment, and were presumably formed by the activity of bilaterian animals. They are preserved commonly as paired circular openings on bedding planes with maximum diameters ranging up to almost 1 cm, and as U- and J-shaped tubes in vertical sections of beds. Discovery of these complex penetrative trace fossils demonstrates that the agronomic revolution started earlier than previously considered.

  8. Content of heavy metals in the sediments of the rivers and adjacent gullies to Relleno de Rio Azul, Rio Azul, San Jose, Costa Rica

    Mora Amador, R.A.

    2003-01-01

    In Costa Rica it is not had studies that have documented heavy the fluvial sediment metal concentrations, caused by point sources of polluting agents, as they are the sites of I deposit of been accustomed to remainders. The potential source of heavy metal concentrations in the study area, it is an active sanitary filling, known like Sanitary Landing Azul River, which is located to the Southeastern of the city of San Jose, in the District of Azul River, Corner of the Union. The site where this made up of a sequence of materials of volcanic origin is located to the filling of Azul River, which could be affected by local fault, this fact would mean a serious threat of contamination of underground waters of the region, then the geological faults constitute very permeable means, able to put in contact the polluting agents of the water-bearing filling with some. The mass of metals deposited in the site, from 1978 to date, metric ton has calculated between 70000 to 100000, which turns it an environmental preoccupation of first order. The results of x-rays fluorescence show the presence of elements like vanadium, chromium, manganese, it receives, zinc rubidium, strontium, potassium, calcium, iron, titanium and yttrium, which show a tendency to present/display high concentrations but in the fine fraction (d [es

  9. Heavy metal contents in sediments of rivers and adjacent streams to the filling of Rio Azul, Rio Azul, San Jose, Costa Rica

    Mora Amador, Raul Alberto

    2003-01-01

    In Costa Rica there are no studies that have documented the concentrations of heavy metals in river sediments, caused by point sources of pollutants, such as the deposits sites of solid waste. The potential source of heavy metals concentrations in the study area, is an active landfill, known as Relleno Sanitario de Rio Azul, which is located southeast of the city of San Jose, in Distrito de Rio Azul de La Union. The site where the landfill Rio Azul is located is composed by a sequence of volcanic materials, which could have been affected by local faulting. This fact would mean a serious threat of contamination of groundwater in the region, geological faults are therefore a highly permeable, able to get in touch the fill pollutants with some aquifer. The mass of metal deposited on the site, from 1978 to date, has been estimated between 70000-100000 tm, which it becomes environmental concern in a first order. The results of X-ray fluorescence show the presence of elements such as vanadium, chromium, magnesium, copper, zinc, rubidium, strontium, potassium, calcium, iron, titanium and yttrium, which show a trend towards more high Concentrates in the fine fraction (d [es

  10. A 565 Ma old glaciation in the Ediacaran of peri-Gondwanan West Africa

    Linnemann, Ulf; Pidal, Agustín Pieren; Hofmann, Mandy; Drost, Kerstin; Quesada, Cecilio; Gerdes, Axel; Marko, Linda; Gärtner, Andreas; Zieger, Johannes; Ulrich, Jens; Krause, Rita; Vickers-Rich, Patricia; Horak, Jana

    2018-04-01

    In the Cadomian orogen of the NE Bohemian Massif and of SW Iberia, a post-Gaskiers glacial event dated at c. 565 Ma has been detected. Such Ediacaran-aged glaciomarine deposits occur in the Weesenstein and Clanzschwitz groups of the Saxo-Thuringian zone (Bohemia) and in the Lower Alcudian group of the southern Central Iberian zone (Iberia). Both areas are parts of Cadomia situated in the Western and Central European Variscides. Glaciomarine sedimentary rocks are characterized by such features as dropstones, flat iron-shaped pebbles (" Bügeleisen- Geschiebe"), facetted pebbles, dreikanters, and zircon grains affected by ice abrasion. For age and provenance determination, LA-ICP-MS U-Pb ages ( n = 1124) and Hf isotope ( n = 446) analyses were performed. The maximum age of the glaciomarine deposits within a Cadomian back-arc basin based on U-Pb analytics resulted in the youngest detrital zircon populations showing ages of 562-565 Ma and of c. 566-576 Ma old zircon derived from granitoid pebbles within the diamictites. The youngest age recorded was 538-540 Ma based on zircon from the plutons which had intruded the previously deformed Ediacaran metasedimentary rocks. Previously described glaciomarine diamictites of Cadomia (Weesenstein, Clanzschwitz, and Orellana diamictites) are most definitely younger than the c. 579-581 Ma Gaskiers glaciation in Newfoundland (Gaskiers) and in SE New England (Squantum). We propose the term Weesenstein- Orellana glaciation for this new Ediacaran glacial event, named after the most relevant regions of exposure. Palaeogeographically, these glaciomarine diamictites and related sedimentary deposits lie on the periphery of the West African Craton (western peri-Gondwana), and evidence has been provided by detrital zircon U-Pb ages and their Hf isotope composition. Correlation with similar glaciomarine deposits in the Anti-Atlas (Bou Azzer) and Saudi Arabia suggests a continued distribution of post-Gaskiers glacial deposits along the

  11. Detección de restricciones en la producción de agave azul (Agave tequilana Weber var. azul mediante percepción remota

    Ramón Ceja Ramírez

    2017-07-01

    Full Text Available El agave azul (Agave tequilana Weber, var. azul se utiliza, principalmente, para la producción del Tequila; una bebida espirituosa. El estado de Jalisco, México, contribuye con el 90% de la producción; esto constituye un importante apoyo a la economía del Estado. El objetivo de la presente investigación fue determinar la superficie ocupada por agave azul, que presentó restricciones en su producción en la región Valles, correspondiente a los municipios de Tequila, Amatitán y El Arenal, en el estado de Jalisco, México, por medio de percepción remota. Se utilizó una imagen adquirida por el satélite LANDSAT 5 el 2 de abril de 2011, la cual se procesó para su calibración radiométrica, corrección atmosférica y georreferenciación. La interpretación digital se hizo a través del proceso de clasificación supervisada utilizando la opción de máxima probabilidad. Los campos de entrenamiento se seleccionaron de información de campo y de la base de datos del Consejo Regulador del Tequila (CRT. Los resultados se plasmaron en mapas temáticos; distribución de agave y no agave y distribución de agave con restricciones. El 45% del área ocupada por el cultivo presentó restricciones relacionadas con: aspectos económicos (restricción tipo 1, plagas y enfermedades (restricción tipo 2 y efectos por exceso de humedad del suelo (restricción tipo 3. Para evaluar la precisión de estos datos se aplicó una matriz de error que reportó una precisión general del 73%. Este valor es aceptable considerando la resolución a 30 m del sensor (LANDSAT 5 y la peculiaridad del cultivo. El uso de imágenes LANDSAT por su resolución espectral y radiométrica es aceptable para el estudio del cultivo del agave azul según lo observado en campo y lo expresado por el procesamiento de la imagen.

  12. The Strontium Isotope Record of Zavkhan Terrane Carbonates: Strontium Isotope Stability Through the Ediacaran-Cambrian Transition

    Petach, Tanya N.

    2015-01-01

    First order trends in the strontium isotopic (87Sr/86Sr) composition of seawater are controlled by radiogenic inputs from the continent and non-radiogenic inputs from exchange at mid-ocean ridges. Carbonates precipitated in seawater preserve trace amounts of strontium that record this isotope ratio and therefore record the relative importance of mid-ocean ridge and weathering chemical inputs to sea water composition. It has been proposed that environmental changes during the Ediacaran-Cambria...

  13. Optimization study of fructans extraction from Agave tequilana Weber azul variety

    Jesús Aarón SALAZAR-LEYVA

    Full Text Available Abstract Agave tequilana Weber azul variety is a valuable source of fructans. In this study, a response surface methodology was employed to optimize the extraction yield of fructans from agave pines. A Box Behnken factorial design was applied to evaluate the effects of several conditions such as extraction temperature, water raw material ratio and extraction time on extraction yield. Under the optimum extraction conditions (extraction temperature of 79.1 °C, water raw material ratio of 5.13 mL/g, and extraction time of 1.48 h fructans extraction yield was 83.12%. The chromatographic profile of the agave crude extract presented four peaks, out of which fructans were the most preponderant (~87%. The obtained results suggest that the response surface methodology is adequate to optimize fructans extraction from Agave tequilana Weber azul variety.

  14. ESTABILIZACIÓN DEL PIGMENTO AZUL ULTRAMAR EN CEMENTO PÓRTLAND BLANCO

    JUAN GUILLERMO MORALES RENDÓN

    2008-01-01

    Full Text Available Se prepararon muestras de cemento azul a partir de cemento Pórtland Blanco Tipo III, según Normas Técnicas Colombianas NTC y pigmento Azul Ultramar U-601 adicionado en un 2% en peso del cemento. El cemento se caracterizó químicamente por fluorescencia de rayos X, y físicamente mediante los ensayos típicos según las NTC. Al pigmento y al cemento se les determinaron sus coordenadas cromáticas por espectrofotometría mediante el sistema CIELAB. Se eligieron varios aditivos y adiciones (entre orgánicos, inorgánicos y minerales para ser adicionados al cemento azul en diferentes dosificaciones en peso. Tanto a las muestras de cemento azul sin aditivo como a aquellas con las diferentes dosificaciones de aditivos, se les determinaron sus características físicas de desempeño y coordenadas cromáticas a diferentes edades de curado en agua saturada con cal (1, 3, 7 y 28 días. Adicionalmente se les determinó el color en las mismas edades a especimenes curados a las condiciones ambientales del laboratorio. Se presentó decoloración total en todos aquellos cementos adicionados con aditivos orgánicos, y decoloración parcial en los cementos adicionados con algunos de los aditivos inorgánicos y ciertas adiciones minerales. Tanto los tiempos de fraguado, como las resistencias a la compresión y demás variables de desempeño experimentaron cambios significativos, en algunos casos positivos y en otros negativos, como consecuencia y efecto de las diferentes dosificaciones utilizadas de cada uno de los aditivos.

  15. Lower Cambrian-Ediacaran Paleogeography and True Polar Wander with New Paleomagnetic Constraints from West African Craton

    Robert, B.; Besse, J.; Blein, O.; Greff-Lefftz, M.; Baudin, T.; Fernando, L.; Meslouh, S.; Belbadaoui, M.

    2014-12-01

    Paleomagnetic data from Laurentia and Baltica continents suggest fast large oscillations of the virtual geomagnetic poles (VGP) from high to low latitudes during the Ediacaran (635-542 Ma). These data are interpreted in the literature either as oscillations of the Earth magnetic dipole between polar and equatorial positions, or as True Polar Wander (TPW), implying a very fast tumbling of continents and perhaps, of whole Earth. In this study, we try to test these hypotheses by bringing new paleomagnetic data on volcanic series from another continent, the West African Craton (WAC). We have sampled well dated pyroclastic and lava flows from the Ouarzazate and Taroudant groups in the Anti-Atlas, (Morocco). 480 samples from 105 sites were thermally demagnetized in our laboratory. Our preliminary results highlight two major groups of directions, mainly carried by hematite, magnetite also contributing sometimes to the magnetization. The first group consists of a dual polarity high inclination direction that may represent the original magnetization. The observed paleolatitude is compatible with that predicted by the lower Cambrian-Ediacaran apparent polar wander path (APWP) of Gondwana, assuming that the WAC was already accreted to Gondwana at this age. Nevertheless, a complete agreement between our pole and the APWP needs a local rotation of around 80° on a vertical axis. The second group displays a single polarity direction, with a shallow inclination and a south-east declination. This direction is close to the expected direction derived from the Permo-Carboniferous segment of the Gondwana APWP, and may represent a remagnetization acquired during the Kiaman reversed polarity superchron. Our preliminary paleomagnetic results thus display large changes in the VGP position, as also evidenced by others on Baltica and Laurentia. However, their interpretation does not favor TPW episodes or equatorial Earth magnetic dipole during the lower Cambrian-Ediacaran periods, but

  16. El duelo y el tiempo mítico en Rosa Cuchillo y La hora azul

    Torres Oyarce, Tania

    2017-01-01

    In this paper, I propose that the novels Rosa Cuchillo and La hora azulproject individual processes of mourning in a mythical social order thatlimits itself to reproduce the phantom of the enclosed nation (Ubilluz) asa (seudo) proposal to solve the internal conflict that took place in Perubetween 1980-2000. In Rosa Cuchillo the main character, Rosa Cuchillo,goes through a process of mourning due to the loss of his terrorist son,Liborio, whereas in La hora azul the main character, Adrián Ormac...

  17. Extração e estabilidade do corante azul de jenipapo (Genipa americana L.)

    Renhe, Isis Rodrigues Toledo

    2008-01-01

    O presente trabalho teve por objetivo a avaliação da potencialidade do fruto do jenipapo como fonte de corante azul natural, objetivando torná-lo tecnicamente viável, bem como identificar o solvente adequado para a extração dos pigmentos do jenipapo, avaliar o efeito do pH e da temperatura na produção do corante, e estudar a estabilidade dos pigmentos obtidos por diferentes solventes. Para a obtenção do corante o experimento foi conduzido para três níveis de solvente (água, solução aquosa de ...

  18. Evidence of early Archean crust in northwest Gondwana, from U-Pb and Hf isotope analysis of detrital zircon, in Ediacaran surpacrustal rocks of northern Spain

    Naidoo, Thanusha; Zimmermann, Udo; Vervoort, Jeff; Tait, Jenny

    2018-03-01

    The Mora Formation (Narcea Group) is one of the oldest Precambrian supracrustal successions in northern Spain. Here, we use U-Pb and in situ Hf isotope analysis on detrital zircon to determine its age and provenance. The youngest U-Pb dates constrain the maximum depositional age of the Mora Formation at 565 ± 11 Ma. Results indicate: (1) a dominant Ediacaran zircon population (33%; 565-633 Ma, Cadomian) within a spectrum of Neoproterozoic ages (40%; 636-996 Ma); and (2) smaller Mesoproterozoic (5%; 1004-1240 Ma), Palaeoproterozoic (11%; 1890-2476 Ma) and Archean (11%; 2519-3550 Ma) populations. Results here do not point to one specific cratonic source area; instead, detritus may have been derived from the West African craton and Amazonia, or even the concealed Iberian basement. The lack of 1.3-1.8 Ga grains suggests exclusion of the Sahara Craton as a major source, but this is not certain. This mixed composition favours a complex source history with reworking of detritus across terrane/craton boundaries. Hafnium isotope compositions indicate a range of crustal and juvenile sources, with initial ɛHf values between -15.8 and 11.1, and Hf model ages from 0.8 to 3.7 Ga. For Neoproterozoic zircons (80%), juvenile components (ɛHf(i) +10) may be related to Rodinia fragmentation and the onset of an active margin setting leading to the Cadomian orogeny. Palaeoproterozoic to Paleoarchean grains (20%) all have negative ɛHf values and Meso- to Eoarchean Hf model ages. This indicates an early (Archean) sialic crustal component for northwestern Gondwana.

  19. Petrogenesis, U-Pb and Sm-Nd geochronology of the Furna Azul Migmatite: partial melting evidence during the San Ignacio Orogeny, Paragua Terrane, SW Amazon Craton

    Nascimento, Newton Diego Couto do; Ruiz, Amarildo Salina; Pierosan, Ronaldo; Lima, Gabrielle Aparecida de; Matos, Joao Batista; Lafon, Jean-Michel; Moura, Candido Augusto Veloso, E-mail: newtongeologia@hotmail.com, E-mail: asruiz@gmail.com, E-mail: ronaldo.pierosan@yahoo.com.br, E-mail: gabilimagel@gmail.com, E-mail: lafonjm@ufpa.br, E-mail: prof.jmatos@gmail.com, E-mail: candido@ufpa.br [Universidade Federal do Para (GEOCIAM/UFPA), Belem, PA (Brazil). Instituto Nacional de Ciencia e Tecnologia de Geociencias da Amazonia

    2016-11-01

    The Furna Azul Migmatite is a ∼10 km{sup 2} complex located in Pontes e Lacerda city, Mato Grosso, Brazil. It belongs to Paragua Terrane, limit with Rio Alegre Terrane, southeast of San Ignacio Province, in Amazon Craton. It consists of transitional metatexites with amphibolite enclaves and dioritic injections. The rocks were divided in residuum rich and leucosome rich; both have three deformation phases marked by folded stromatic layers affected by spaced foliation and metamorphosed in amphibolite facies, represented by garnet, biotite, sillimanite, and by the clinopyroxene in the enclaves. The metamorphic retrograde to greenschist is marked by formation of chlorite, muscovite and prehnite. Residuum-rich metatexites show higher CaO and Na{sub 2}O contents, separating them from K{sub 2}O, Ba and Rb enriched transitional metatexites. U-Pb on zircon and Sm-Nd whole-rocks dating indicates that the residuum-rich metatexite crystallized at 1436 ± 11 Ma, with a T{sub DM} age of 1.90 Ga and ε{sub Nd(1.43)} of -0.54, whereas the dioritic injection crystallized at 1341,7 ± 17 Ma with a T{sub DM} age of 1.47 Ga and ε{sub Nd(1.34)} of 3.39. These results indicate that the Furna Azul Migmatite protolith was formed during the San Ignacio Orogeny and was reworked during the same orogeny, as basement for collisional to post-magmatic granites from Pensamiento Intrusive Suite. (author)

  20. Generation of Maillard compounds from inulin during the thermal processing of Agave tequilana Weber Var. azul.

    Mancilla-Margalli, Norma A; López, Mercedes G

    2002-02-13

    During the cooking process of Agave tequilana Weber var. azul to produce tequila, besides the hydrolysis of inulin to generate fermentable sugars, many volatiles, mainly Maillard compounds, are produced, most of which may have a significant impact on the overall flavor of tequila. Exudates (agave juice) from a tequila company were collected periodically, and color, Brix, fructose concentration, and reducing sugars were determined as inulin breakdown took place. Maillard compounds were obtained by extraction with CH(2)Cl(2), and the extracts were analyzed by GC-MS. Increments in color, Brix, and reducing sugars were observed as a function of time, but a decrease in fructose concentration was found. Many Maillard compounds were identified in the exudates, including furans, pyrans, aldehydes, and nitrogen and sulfur compounds. The most abundant Maillard compounds were methyl-2-furoate, 2,3-dihydroxy-3,5-dihydro-6-methyl-4(H)-pyran-4-one, and 5-(hydroxymethyl)furfural. In addition, a series of short- and long-chain fatty acids was also found. A large number of the volatiles in A. tequilana Weber var. azul were also detected in tequila extracts, and most of these have been reported as a powerful odorants, responsible for the unique tequila flavor.

  1. Biossorção de azul de metileno utilizando resíduos agroindustriais

    Andressa C. Honorato

    2015-07-01

    Full Text Available O presente trabalho avaliou a capacidade de adsorção do corante azul de metileno nos resíduos da palha de milho e da bainha do palmito pupunha in natura. A caracterização dos resíduos foi determinada utilizando-se a microscopia eletrônica de varredura e espectroscopia na região do infravermelho a qual indicou a presença de grupos carboxílicos, hidroxila e carbonila. O tempo necessário para que o sistema atingisse o equilíbrio para ambos os resíduos foi de 240 min, seguindo uma cinética descrita pelo modelo de pseudo-segunda ordem. A capacidade máxima de adsorção foi de 102,8 mg g-1 para o resíduo da palha de milho, seguindo o modelo de isoterma de Langmuir e 50,9 mg g-1 para o resíduo de palmito pupunha, sendo que o modelo que melhor se ajusta foi Freundlich. Desta forma, esses resíduos são promissores para a adsorção do corante azul de metileno em efluentes.

  2. Zn-binding AZUL domain of human ubiquitin protein ligase Ube3A

    Lemak, Alexander; Yee, Adelinda [University of Toronto, and Northeast Structural Genomics Consortium, Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics (Canada); Bezsonova, Irina, E-mail: bezsonova@uchc.edu [University of Connecticut Health Center, Department of Molecular Microbial and Structural Biology (United States); Dhe-Paganon, Sirano, E-mail: sirano.dhepaganon@utoronto.ca [University of Toronto, Structural Genomics Consortium (Canada); Arrowsmith, Cheryl H., E-mail: carrow@uhnresearch.ca [University of Toronto, and Northeast Structural Genomics Consortium, Ontario Cancer Institute, Campbell Family Cancer Research Institute and Department of Medical Biophysics (Canada)

    2011-09-15

    Ube3A (also referred to as E6AP for E6 Associated Protein) is a E3 ubiquitin-protein ligase implicated in the development of Angelman syndrome by controlling degradation of synaptic protein Arc and oncogenic papilloma virus infection by controlling degradation of p53. This article describe the solution NMR structure of the conserved N-terminal domain of human Ube3A (residues 24-87) that contains two residues (Cys44 and Arg62) found to be mutated in patients with Angelman syndrome. The structure of this domain adopts a novel Zn-binding fold we called AZUL (Amino-terminal Zn-finger of Ube3a Ligase). The AZUL domain has a helix-loop-helix architecture with a Zn ion coordinated by four Cys residues arranged in Cys-X{sub 4}-Cys-X{sub 4}-Cys-X{sub 28}-Cys motif. Three of the Zn-bound residues are located in a 23-residue long and well structured loop that connects two {alpha}-helicies.

  3. Zn-binding AZUL domain of human ubiquitin protein ligase Ube3A

    Lemak, Alexander; Yee, Adelinda; Bezsonova, Irina; Dhe-Paganon, Sirano; Arrowsmith, Cheryl H.

    2011-01-01

    Ube3A (also referred to as E6AP for E6 Associated Protein) is a E3 ubiquitin-protein ligase implicated in the development of Angelman syndrome by controlling degradation of synaptic protein Arc and oncogenic papilloma virus infection by controlling degradation of p53. This article describe the solution NMR structure of the conserved N-terminal domain of human Ube3A (residues 24-87) that contains two residues (Cys44 and Arg62) found to be mutated in patients with Angelman syndrome. The structure of this domain adopts a novel Zn-binding fold we called AZUL (Amino-terminal Zn-finger of Ube3a Ligase). The AZUL domain has a helix-loop-helix architecture with a Zn ion coordinated by four Cys residues arranged in Cys-X 4 -Cys-X 4 -Cys-X 28 -Cys motif. Three of the Zn-bound residues are located in a 23-residue long and well structured loop that connects two α-helicies.

  4. Distinguishing geology from biology in the Ediacaran Doushantuo biota relaxes constraints on the timing of the origin of bilaterians.

    Cunningham, John A; Thomas, Ceri-Wyn; Bengtson, Stefan; Kearns, Stuart L; Xiao, Shuhai; Marone, Federica; Stampanoni, Marco; Donoghue, Philip C J

    2012-06-22

    The Ediacaran Doushantuo biota has yielded fossils that include the oldest widely accepted record of the animal evolutionary lineage, as well as specimens with alleged bilaterian affinity. However, these systematic interpretations are contingent on the presence of key biological structures that have been reinterpreted by some workers as artefacts of diagenetic mineralization. On the basis of chemistry and crystallographic fabric, we characterize and discriminate phases of mineralization that reflect: (i) replication of original biological structure, and (ii) void-filling diagenetic mineralization. The results indicate that all fossils from the Doushantuo assemblage preserve a complex mélange of mineral phases, even where subcellular anatomy appears to be preserved. The findings allow these phases to be distinguished in more controversial fossils, facilitating a critical re-evaluation of the Doushantuo fossil assemblage and its implications as an archive of Ediacaran animal diversity. We find that putative subcellular structures exhibit fabrics consistent with preservation of original morphology. Cells in later developmental stages are not in original configuration and are therefore uninformative concerning gastrulation. Key structures used to identify Doushantuo bilaterians can be dismissed as late diagenetic artefacts. Therefore, when diagenetic mineralization is considered, there is no convincing evidence for bilaterians in the Doushantuo assemblage.

  5. Decoupling of body-plan diversification and ecological structuring during the Ediacaran-Cambrian transition: evolutionary and geobiological feedbacks.

    Mángano, M Gabriela; Buatois, Luis A

    2014-04-07

    The rapid appearance of bilaterian clades at the beginning of the Phanerozoic is one of the most intriguing topics in macroevolution. However, the complex feedbacks between diversification and ecological interactions are still poorly understood. Here, we show that a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran-Cambrian transition indicates that body-plan diversification and ecological structuring were decoupled. The appearance of a wide repertoire of behavioural strategies and body plans occurred by the Fortunian. However, a major shift in benthic ecological structure, recording the establishment of a suspension-feeder infauna, increased complexity of the trophic web, and coupling of benthos and plankton took place during Cambrian Stage 2. Both phases were accompanied by different styles of ecosystem engineering, but only the second one resulted in the establishment of the Phanerozoic-style ecology. In turn, the suspension-feeding infauna may have been the ecological drivers of a further diversification of deposit-feeding strategies by Cambrian Stage 3, favouring an ecological spillover scenario. Trace-fossil information strongly supports the Cambrian explosion, but allows for a short time of phylogenetic fuse during the terminal Ediacaran-Fortunian.

  6. Superficie específica de una bentonita mediante la adsorción de azul de metileno

    Pinzón Bello, Jorge Alejo

    2010-01-01

    Se estudió la determinación de la superficie específica de una bentonita colombiana, procedente del Valle del Cauca, mediante la adsorción de azul de metileno, a 298 K. Este método se comparó con el de la adsorción de nitrógeno a 77 K.

  7. Petrografía, caracterización geoquímica y análisis microestructural del granito del cerro Siempre Amigos, sierras de Azul, Tandilia

    Angeletti, Melisa; Frisicale, María Cristina; Dimieri, Luis V

    2016-01-01

    El cerro Siempre Amigos integra las sierras de Azul, Tandilia, distante 28 km al sur de la ciudad de Azul y 3 km al norte de la megacizalla de Azul, zona de cizalla subvertical donde el basamento se encuentra deformado a milonitas y ultramilonitas. La litología predominante en el cerro Siempre Amigos es un granito paleoproterozoico deformado que en el centro y hacia los bordes se encuentra interdigitado con una roca gnéisica y cuerpos de anfibolitas subverticales de rumbo similar a la foliaci...

  8. A estratégia Oceano Azul como proposta de valor: o caso dos ginásios/health clubs portugueses

    Vieira, Elsa Regina Monteiro

    2016-01-01

    Metaforicamente, Kim e Mauborgne (2005) referem que o mercado é constituído por dois oceanos, o vermelho e o azul. O oceano vermelho representa todas as indústrias que existem hoje. O oceano azul considera todas as indústrias que ainda não existem, representa assim, o mercado não explorado, onde se pode criar a procura e onde existem oportunidades de elevado crescimento e rentabilidade. A esta abordagem Kim e Mauborgne (2005) chamam Estratégia Oceano Azul. Esta tese tem como objetivo geral de...

  9. Physical-geographical landscape of the tourist circuit Chilpancingo-Azul, Guerrero State, Mexico

    Julio C. Carbajal Monroy

    2011-02-01

    Full Text Available This work deals with the delimitation of physical-geographical landscapes of the territory of the Tourist Circuit Chilpancingo Azul, at Guerrero's State central region, from geo-ecological conception for the physical-geographical synthetic classification of territorial units. This approach obtained territorial units and its hierarchical classification using a taxonomic system of localities, neighborhoods and boroughs (smallest categories. Taking into account the 1:100 000 scale different geographical units were determined: 3 localities, 31 neighborhoods and 177 boroughs. The characterization of these territorial units include lithologic constitution, geomorphological conditions (morphogenesis and morphometrics and spatial distribution of major types of soils and vegetation and land uses in the territory.

  10. Idealismo e imaginario falangista en las primeras novelas de la División Azul

    Valeria Possi

    2017-07-01

    Full Text Available Este artículo se centra en el análisis de la ideología, la retórica y el imaginario falangista utilizado en las novelas españolas escritas por los veteranos de guerra de la División Azul en los años 40 y 50. El estudio versa en particular sobre la representación de la Segunda Guerra Mundial, la figura del héroe y el arquetipo del militante falangista entregado a la causa, y las imágenes de la muerte de los soldados en el frente. Este trabajo demuestra que los escritores se alejan de un imaginario realista para crear una representación idealizada y estética de la muerte.

  11. El control de la limpieza de las arenas por medio del ensayo del azul de metileno

    Ramírez Ortiz, J. L.

    1986-07-01

    Full Text Available In the first part of this work, the main lines of the investigation work developed at LABEIN on the «Influence of the limy and clayey slimes from calcareous crushed sands on concrete properties» are presented. As a consequence of it, new limits are proposed to consideration regarding the admissible content of slime in crushed sands, reaching a limit higher than 15%, controling the slime nature by means of an equivalent of normal sand and specially by Methylene Blue. The second part of the work is devoted to the development of the methodology for the obtention of Methylene Blue, in sands used in the elaboration of concrete which have a little amount of clay, taking as a base the method applied by French normative, duly adapted and with different expression of the results.Se muestran, en la primera parte del artículo, las líneas fundamentales del trabajo de investigación desarrollado en LABEIN, sobre la «Influencia de los finos calizos y arcillosos de arenas calizas de machaqueo, en las propiedades del hormigón». Como consecuencia del mismo, se proponen nuevos límites a considerar respecto al contenido admisible de finos en las arenas calizas de machaqueo, llegando a un límite superior del 15%, controlando la naturaleza de los finos por medio del equivalente de arena a vista, y, sobre todo, por el Azul de Metileno. En la segunda parte del artículo, se desarrolla la metodología utilizada para obtener el Azul de Metileno, en arenas utilizadas en la confección de hormigón, que poseen poca arcilla, basándose en el método aplicado por la normativa francesa, adaptado convenientemente y con diferente expresión de resultados.

  12. Physical volcanology, geochemistry and basin evolution of the Ediacaran volcano-sedimentary succession in the Bas Draâ inlier (Ouarzazate Supergroup, Western Anti-Atlas, Morocco)

    Karaoui, Brahim; Breitkreuz, Christoph; Mahmoudi, Abdelkader; Youbi, Nasrrddine

    2014-11-01

    New geologic mapping, lithofacies and granulometric analysis, and geochemistry from the volcano-sedimentary successions of the central part of the Bas Draâ inlier, Western Anti-Atlas, constrain the Ediacaran Ouarzazate Supergroup evolution during the post-collisional stage of the Pan-African orogeny. Volcanosedimentary facies analysis is the key aspect of the present contribution. We distinguished sixteen terrestrial volcanosedimentary lithofacies in the Bas Draâ succession (BDS), which reaches a total thickness of 2000 m. BDS evolution can be grouped into four units (Aouinet Aït Oussa I to IV, AO I-AO IV). The earliest volcanic activity produced rhyolitic ignimbrite sheets (AO I), which had been considered as lava flows by previous workers, and which were presumably related to caldera system(s). During AO II, a complex of high-silica andesitic and rhyolitic lavas formed, punctuated by the explosive eruption of a high-temperature silica-rich magma leading to the formation of parataxitic ignimbrite. AO III consists of basalt and andesite lava fields and small explosive, in parts phreatomagmatic volcanic vents. It is dissected by fluvial systems depositing external non-volcanic and local volcanic debris. BDS evolution terminated with the formation of a large SiO2-rich lava dome complex (AO IV), accompanied by small basalt effusive event. Volcanosedimentary facies analysis infers that the BDS evolved in a continental extensional setting developing in a low topography under humid paleoclimatic conditions. Alteration textures are dominated by a piemontite-calcite-albite-quartz (+ iron oxides) assemblage. Chemical analysis of BDS volcanic and subvolcanic rocks belongs to high-k calc-alkaline and alkali-calcic to alkaline magmatic trend typical for a post-collision setting. Trace elements spidergrams show a pattern typical for subduction-related suites of orogenic belts. REE patterns show moderate enrichment in LREE relative to flat HREE, with strong negative Eu

  13. Suicídio e o jogo da Baleia Azul analisados na perspectiva de Anomia de Émile Durkheim

    Irineu Francisco Barreto Junior

    2017-06-01

    Full Text Available Este artigo apresenta uma síntese das principais ideias de Durkheim, representante da sociologia positivista. São revisitados os conceitos de fato social, solidariedade e anomia com o intuito de analisar os suicídios ocorridos no ano de 2017 e associados ao jogo da Baleia Azul, fenômeno mundial da internet e da Sociedade da Informação. O conceito de anomia pode ser compreendido como ausência de normas, que decorre de grande turbulência social, heteronomia, perda dos laços sociais e de solidariedade. Nessa perspectiva, o artigo problematiza a associação entre o conceito de suicídio anômico e as mortes associadas ao jogo da Baleia Azul.

  14. Superficie específica de una bentonita mediante la adsorción de azul de metileno

    Jorge Alejo Pinzón Bello

    2010-07-01

    Full Text Available Se estudió la determinación de la superficie específica de una bentonita colombiana, procedente del Valle del Cauca, mediante la adsorción de azul de metileno, a 298 K. Este método se comparó con el de la adsorción de nitrógeno a 77 K.

  15. Simulation of regional-scale groundwater flow in the Azul River basin, Buenos Aires Province, Argentina

    Varni, Marcelo R.; Usunoff, Eduardo J.

    A three-dimensional modular model (MODFLOW) was used to simulate groundwater flow in the Azul River basin, Buenos Aires Province, Argentina, in order to assess the correctness of the conceptual model of the hydrogeological system. Simulated heads satisfactorily match observed heads in the regional water-table aquifer. Model results indicate that: (1) groundwater recharge is not uniform throughout the region but is best represented by three recharge rates, decreasing downgradient, similar to the distribution of soils and geomorphological characteristics; and (2) evapotranspiration rates are larger than previous estimates, which were made by using the Thornthwaite-Mather method. Evapotranspiration rates estimated by MODFLOW agree with results of independent studies of the region. Model results closely match historical surface-flow records, thereby suggesting that the model description of the aquifer-river relationship is correct. Résumé Un modèle modulaire tridimensionnel (MODFLOW) a été utilisé pour simuler les écoulements souterrains dans le bassin de la rivière Azul (Province de Buenos Aires, Argentine), dans le but d'évaluer la justesse du modèle conceptuel du système hydrogéologique. La piézométrie simulée s'ajuste de façon satisfaisante à celle observée pour l'ensemble de la nappe. Les résultats du modèle indiquent que: (1) la recharge de la nappe n'est pas uniforme sur toute la région, mais qu'elle est mieux approchée par trois valeurs différentes, décroissant vers l'aval-gradient, en suivant la même distribution que les sols et les caractéristiques géomorphologiques et (2) l'évapotranspiration est nettement plus importante que prévu initialement à partir de la méthode de Thornthwaite-Mather. Les valeurs d'évapotranspiration fournies par MODFLOW concordent bien avec les résultats d'autres études portant sur la région. Les résultats du modèle reproduisent convenablement les chroniques de débit des écoulements de surface

  16. Late Ediacaran-Cambrian structures and their reactivation during the Variscan and Alpine cycles in the Anti-Atlas (Morocco)

    Soulaimani, A.; Michard, A.; Ouanaimi, H.; Baidder, L.; Raddi, Y.; Saddiqi, O.; Rjimati, E. C.

    2014-10-01

    The post-Pan-African evolution of the northern border of the West African Craton is largely controlled by the remobilisation of Late Neoproterozoic basement faults. The Upper Ediacaran volcanic and volcano-sedimentary sequences of the Ouarzazate Group show dramatic and rapid thickness changes, consistent with active extensional faulting associated with post-orogenic collapse and incipient continental rifting. The geometry and kinematics of these faults differ from west to east in the Anti-Atlas. N- to NE-trending faults dominate in western Anti-Atlas in response to E-W to NW-SE pure extension, while a transtensive opening regime characterize the central (Bou Azzer) and eastern (Saghro-Ougnate) Anti-Atlas. The marine incursion in the west-central Anti-Atlas during the late Ediacaran-Early Cambrian occurred without major geodynamical break between the continental Ouarzazate Group and marine sediments of the Adoudou Fm. Extensional tectonics went on during the Early Cambrian, being concentrated in the western and central parts of the belt. From Middle Cambrian to Lower Devonian and mainly due to thermal subsidence, the Anti-Atlas basement was buried under marine sediments with dominant south-derived detrital input. Basement faults control the distribution of subsiding versus shallow areas. During the Middle-Late Devonian, the dislocation of the Saharan platform occurred, mainly in the eastern Anti-Atlas where Precambrian faults were also remobilized during the Early Carboniferous. During the Variscan orogeny, the Paleozoic series of the Anti-Atlas basin were involved in folding tectonics, concomitant with the uplift of Proterozoic basement blocks bounded by inherited basement faults. The pre-existing rift-related faults were variably inverted across the Anti-Atlas. In the westernmost part of the belt, Variscan shortening induced positive inversions along the remobilized basement faults, but in some cases, some faults preserved an apparently normal throw. Some hidden

  17. Nanofibers of cellulose bagasse from Agave tequilana Weber var. azul by electrospinning: preparation and characterization.

    Robles-García, Miguel Ángel; Del-Toro-Sánchez, Carmen Lizette; Márquez-Ríos, Enrique; Barrera-Rodríguez, Arturo; Aguilar, Jacobo; Aguilar, José A; Reynoso-Marín, Francisco Javier; Ceja, I; Dórame-Miranda, R; Rodríguez-Félix, Francisco

    2018-07-15

    In this study, cellulose of bagasse from Agave tequilana Weber var. azul was extracted to elaborate nanofibers by the electrospinning technique. Fiber characterization was performed using Transmission Electron Microscopy (TEM), x-ray, Fournier Transform-InfraRed (FT-IR) spectroscopy, and thermal analysis by Differential Scanning Calorimetry-Thermogravimetric Analysis (DSC-TGA). Different diameters (ranging from 54.57 ± 0.02 to 171 ± 0.01 nm) of nanofibers were obtained. Cellulose nanofibers were analyzed by means of x-ray diffraction, where we observed a total loss of crystallinity in comparison with the cellulose, while FT-IR spectroscopy revealed that the hemicellulose and lignin present in the agave bagasse were removed. Thermal analysis showed that nanofibers exhibit enhanced thermal properties, and the zeta potential value (-32.5 mV) demonstrated moderate stability in the sample. In conclusion, the nanofibers obtained provide other alternatives-of-use for this agro-industrial residue and could have potential in various industrial applications, among these encapsulation of bioactive compounds and reinforcing material, to mention a few. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. The Benthonic Macroinvertebrates of Pozo Azul (Gaira River Basin, Colombia and their Relationship with Water Quality

    Francisco Guerrero-Bolaño

    2003-07-01

    Full Text Available On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macroinvertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River basin, Magdalena, Colombia. The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were found 588 individuals distributed in 11 orders and 38 families. The most representative orders were Trichoptera, Coleoptera, Diptera and Ephemeroptera. The most representative families were Baetidae, Simullidae, Perlidae, Chironomidae, and Hydropsychidae, in this rank of abundance. The BMWP index for the relationship between the community structure and the water quality (adapted by Universidad del Valle, Cali, Colombia was calculated. According to this index the water quality was optimum. Also, given the general characteristics of the site studied, the water mass quality was classified as good and oligosaprobit, based on the saprobit ecology. It is possible that this state was reached due to stabilization after a small perturbation induced by coffee cultivation in the zone.

  19. Optimization of Agave tequilana Weber var. Azul Juice Spray Drying Process

    Alejandra Chávez-Rodríguez

    2014-01-01

    Full Text Available In this work, the response surface methodology was employed to optimize the microencapsulation of Agave tequilana Weber var. azul juice with whey protein isolated using a spray drying technique. A Box-Behnken design was used to establish optimum spray drying conditions for Agave tequilana juice. The process was optimized to obtain maximum powder yield with the best solubility time, hygroscopicity, bulk density, water activity, and reducing sugars. The independent parameters for the spray drying process were outlet temperature of 70–80°C, atomizer speed of 20000–30000 rpm, and airflow of 0.20–0.23 m3 s−1. The best spray drying condition was at outlet temperature of 80°C, atomizer speed of 20000 rpm, and air flow rate of 0.23 m3 s−1 to obtain maximum powder yield (14.65%bm, minimum solubility time (352.8 s, maximum bulk density (560 kg m−3, minimum hygroscopicity (1.9×10-7 kgwater s−1, and minimum aw (0.39. The Agave tequilana powder may be considered as an interesting source of dietary fiber used as food additive in food and nutraceutical industries.

  20. TERAPIA FOTODINÂMICA COM AZUL DE METILENO SOBRE CEPA DE Staphylococcus aureus RESISTENTE À METICILINA

    Mirian Alves Freitas

    2017-01-01

    Full Text Available S. aureus é o agente etiológico de maior importância associado às infecções adquiridas tanto em âmbito comunitário ou hospitalar, devido a sua capacidade de desenvolver resistência às terapias convencionais. A Terapia Fotodinâmica (TFD surge como alternativa a ser utilizada no controle de cepas resistentes aos antibioticos. O objetivo do presente estudo é avaliar os efeitos da TFD com Azul de Metileno (AM sobre cepas de S. aureus resistente à meticilina (MRSA. As amostras foram diluídas em PBS estéril de acordo com a escala 0,5 de MacFarland. Os grupos foram compostos com diferentes concentrações de AM, incubados no escuro durante 15 minutos e irradiados por LED Biopdi/Irrad-Led5 em 660nm com fluência de 10 J/cm². Posteriormente, foram semeadas e incubadas à 37ºC por 24 horas. A contagem de Unidades Formadoras de Colônias (UFCs demonstrou que a TFD foi eficaz na menor concentração testada de AM sobre cepas de MRSA.

  1. Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

    George E. Williams

    2016-07-01

    Full Text Available Proterozoic (pre-Ediacaran glaciations occurred under strongly seasonal climates near sea level in low palaeolatitudes. Metre-scale primary sand wedges in Cryogenian periglacial deposits are identical to those actively forming, through the infilling of seasonal (winter thermal contraction-cracks in permafrost by windblown sand, in present-day polar regions with a mean monthly air temperature range of 40 °C and mean annual air temperatures of −20 °C or lower. Varve-like rhythmites with dropstones in Proterozoic glacial successions are consistent with an active seasonal freeze–thaw cycle. The seasonal (annual oscillation of sea level recorded by tidal rhythmites in Cryogenian glacial successions indicates a significant seasonal cycle and extensive open seas. Palaeomagnetic data determined directly for Proterozoic glacial deposits and closely associated rocks indicate low palaeolatitudes: Cryogenian deposits in South Australia accumulated at ≤10°, most other Cryogenian deposits at 54° during Proterozoic low-latitude glaciations, whereby the equator would be cooler than the poles, on average, and global seasonality would be greatly amplified.

  2. Efeitos da infusão de azul de metileno em equinos após a administração de lipopolissacarídeo

    Borges, José Henrique Saraiva [UNESP

    2009-01-01

    A endotoxemia é um distúrbio grave na clínica veterinária, sendo uma das principais causas de mortalidade em equinos.Trabalhos recentes relatam a eficácia do azul de metileno na prevenção dos danos impostos pelo óxido nítrico. Este estudo foi concebido com o fito de avaliar os efeitos do azul de metileno sobre as respostas clínica, celular e bioquímica, na endotoxemia experimental em equinos. Os animais foram divididos em três grupos. LPS+AM recebeu LPS e foi tratado com 3mg/kg de azul de met...

  3. The origin of groundwater composition in the Pampeano Aquifer underlying the Del Azul Creek basin, Argentina.

    Zabala, M E; Manzano, M; Vives, L

    2015-06-15

    The Pampean plain is the most productive region in Argentina. The Pampeano Aquifer beneath the Pampean plain is used mostly for drinking water. The study area is the sector of the Pampeano Aquifer underlying the Del Azul Creek basin, in Buenos Aires province. The main objective is to characterize the chemical and isotopic compositions of groundwater and their origin on a regional scale. The methodology used involved the identification and characterization of potential sources of solutes, the study of rain water and groundwater chemical and isotopic characteristics to deduce processes, the development of a hydrogeochemical conceptual model, and its validation by hydrogeochemical modelling with PHREEQC. Groundwater samples come mostly from a two-depth monitoring network of the "Dr. Eduardo J. Usunoff" Large Plains Hydrology Institute (IHLLA). Groundwater salinity increases from SW to NE, where groundwater is saline. In the upper basin groundwater is of the HCO3-Ca type, in the middle basin it is HCO3-Na, and in the lower basin it is ClSO4-NaCa and Cl-Na. The main processes incorporating solutes to groundwater during recharge in the upper basin are rain water evaporation, dissolution of CO2, calcite, dolomite, silica, and anorthite; cationic exchange with Na release and Ca and Mg uptake, and clay precipitation. The main processes modifying groundwater chemistry along horizontal flow at 30 m depth from the upper to the lower basin are cationic exchange, dissolution of silica and anorthite, and clay precipitation. The origin of salinity in the middle and lower basin is secular evaporation in a naturally endorheic area. In the upper and middle basins there is agricultural pollution. In the lower basin the main pollution source is human liquid and solid wastes. Vertical infiltration through the boreholes annular space during the yearly flooding stages is probably the pollution mechanism of the samples at 30 m depth. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Morro Azul Observatory: A New Center for Teaching and Popularization of Astronomy.

    Bretones, Paulo Sergio; Cardoso de Oliveira, Vladimir

    2002-08-01

    In 1999, the Instituto Superior de Ciências Aplicadas (ISCA Faculdades de Limeira) started a project to build an observatory and initiate several astronomy related activities in the city of Limeira and region (São Paulo state) with the aim of teaching and popularizing astronomy. After contracting teachers, a technician and an intern, the Morro Azul Observatory was inaugurated in March 2000 as a part of the geosciences department of ISCA Faculdades. This poster describes the development phases of the Observatory, the activities initiated by the Observatory, and assesses the impact of the project. Several issues will be discussed such as the criteria for choosing the site, buildings, instruments, group visits, and particularly the goals that were reached. The Observatory, as described here, serves as a model for other centers with the same purpose in the country. The achievements of this project include the creation of two astronomical disciplines for the geography course and liaisons with other courses such as tourism, pedagogy, social communication and engineering. New activities were initiated, educational materials created, and the Observatory is now part of the regions teaching network and is in contact with other Brazilian and foreign centers. This poster presents the results from report analyses, visitor records, the local media, goal strategy assessment, and the current state of the project. It concludes with an evaluation of the social commitment of the Observatory, its initiatives for the constant renewal and growth of the project, its policy of maintaining the activities and interchange with other national and international astronomy centers, and the future perspectives in terms of its contribution for the research in science education.

  5. Registro de un Monstruo Diprósopo de Tiburón Azul (Prionace glauca) en Chile

    Hevia-Hormazábal, Valentina; Pastén-Marambio, Víctor; Vega, Alonso

    2011-01-01

    Un espécimen de siameses de tiburón azul, Prionace glauca, fue recolectado durante actividades de pesca en el norte de Chile. Según una clasificación basada en el grado de duplicación y el sitio de fusión de los gemelos, el espécimen corresponde a un monstruo del tipo diprósopo tetroftalmo. El individuo tiene una duplicación craneofacial parcial con presencia de cuatro globos oculares e igual número de narinas. Las cavidades orales están interconectadas convergiendo en una única faringe. El t...

  6. Juan Ramón Jiménez y Rubén Darío: recorrido de un arte azul

    Giuliana, Virginie

    2015-01-01

    El presente estudio pretende llamar la atención sobre algunos puntos de la trayectoria del color azul desde la época modernista bajo la influencia dariana hasta Diario de un poeta reciencasado (1916) a través de un repaso de la presencia del color azul en la poesía modernista como representación de varios símbolos (la melancolía, el sueño, etc.) o un color heredado de la poesía francesa romántica y simbolista hasta la metamorfosis literaria en el Diario, como renovación literaria hacia la poe...

  7. A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

    Benjamim Bley de Brito Neves

    Full Text Available ABSTRACT: Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB belt. Three igneous supersuites are recognized: a epidote-bearing granodiorites and tonalites ("Conceição" type; b high-K calc-alkaline granites ("Itaporanga" type; c biotite granodiorites of trondhjemite affinity ("Serrita" type. A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil.

  8. The origin of groundwater composition in the Pampeano Aquifer underlying the Del Azul Creek basin, Argentina

    Zabala, M.E.; Manzano, M.; Vives, L.

    2015-01-01

    The Pampean plain is the most productive region in Argentina. The Pampeano Aquifer beneath the Pampean plain is used mostly for drinking water. The study area is the sector of the Pampeano Aquifer underlying the Del Azul Creek basin, in Buenos Aires province. The main objective is to characterize the chemical and isotopic compositions of groundwater and their origin on a regional scale. The methodology used involved the identification and characterization of potential sources of solutes, the study of rain water and groundwater chemical and isotopic characteristics to deduce processes, the development of a hydrogeochemical conceptual model, and its validation by hydrogeochemical modelling with PHREEQC. Groundwater samples come mostly from a two-depth monitoring network of the “Dr. Eduardo J. Usunoff” Large Plains Hydrology Institute (IHLLA). Groundwater salinity increases from SW to NE, where groundwater is saline. In the upper basin groundwater is of the HCO 3 -Ca type, in the middle basin it is HCO 3 -Na, and in the lower basin it is ClSO 4 –NaCa and Cl–Na. The main processes incorporating solutes to groundwater during recharge in the upper basin are rain water evaporation, dissolution of CO 2 , calcite, dolomite, silica, and anorthite; cationic exchange with Na release and Ca and Mg uptake, and clay precipitation. The main processes modifying groundwater chemistry along horizontal flow at 30 m depth from the upper to the lower basin are cationic exchange, dissolution of silica and anorthite, and clay precipitation. The origin of salinity in the middle and lower basin is secular evaporation in a naturally endorheic area. In the upper and middle basins there is agricultural pollution. In the lower basin the main pollution source is human liquid and solid wastes. Vertical infiltration through the boreholes annular space during the yearly flooding stages is probably the pollution mechanism of the samples at 30 m depth. - Highlights: • The work studies the

  9. Levantamento de plantas medicinais nativas da Fazenda Azulão em Dourados-MS

    C. Bratti

    2013-01-01

    Full Text Available O presente trabalho teve por objetivo identificar as espécies medicinais nativas em um fragmento de mata situada na Fazenda Azulão, em Dourados/MS, baseando-se no conhecimento popular de mateiros da região, com intuito de gerar subsídios para perpetuar a preservação, a diversidade e variabilidade das espécies, bem como, incentivar populações locais a valorizar e preservar esses recursos naturais, retardando o impacto sobre a biodiversidade. Partes das plantas indicadas como medicinais foram coletadas, as quais foram identificadas mediante literaturas especializadas e por comparações com plantas depositadas no Herbário da Cidade Universitária de Dourados. Foram identificadas 61 espécies distribuídas em 35 famílias e 53 gêneros. As famílias Asteraceae (9, Fabaceae (5 e Piperaceae (4 foram as que apresentaram o maior número de espécies. Dentre as formas de vida encontradas na vegetação nativa do local, as espécies medicinais de hábito arbustivo (39,34% foram as que apresentaram os maiores valores, seguido pelas herbáceas (27,86%, arbóreas (24,6%, e lianas (8,2%. As partes das plantas mais utilizadas são as folhas, seguidas da raiz e casca. Com base nos resultados obtidos nesse estudo, as indicações da utilização das plantas medicinais podem fornecer subsídios para estudos bioquímicos e farmacológicos, diminuindo os custos e o tempo na extração de princípios ativos, bem como, permitir o fortalecimento do conhecimento cultural da comunidade local, incentivando a preservação ambiental de diversas espécies medicinais utilizadas na região. Novos estudos devem ser conduzidos no Estado do Mato Grosso do Sul, a fim de se garantir o registro de dados mais precisos sobre as espécies medicinais ocorrentes.

  10. Chemical-mineralogical characterization and Moessbauer spectroscopy of aquamarine from Pedra Azul, Northeast of Minas Gerais

    Viana, Rubia Ribeiro; Jordt-Evangelista, Hanna; Costa, Geraldo Magela da

    2001-01-01

    Aquamarines from three pegmatites located the vicinities of the Pedra Azul city, Minas Gerais state, were investigated in terms of chemical composition, physical properties and Moessbauer spectroscopy. The small lenticular pegmatite bodies are usually less than 5 m wide and exhibit a conspicuous mineralogical and textural zoning. The last thermal event in these pegmatites, determined by K-Ar method in muscovite, is of Neo proterozoic age, coincident with the late stages of the Brasiliano tectono- metamorphic cycle. Chemical analyses showed that sodium is the alkali with higher contents in the aquamarines, thus enabling their classification as sodic beryls. In zoned samples there is an increase of Fe as well as Mn from center to border, while no systematic variation could be detected for other elements. The specific gravity of 2.72 to 2.80 g/cm 3 is higher than the values determined for samples from other pegmatites of Minas Gerais. The refraction indices are ne=1.569 - 1.579 and NW= 1.573 - 1.581 and the birefringence varies from 0.002 to 0.008. The refraction indices increase with the Be O content. The color of aquamarines varies from medium to light blue, sometimes greenish blue. Moessbauer spectra obtained at room temperature and at 80 K show that Fe 2+ is the main chromophore-ion and suggest that the iron is present in octahedral sites as well as in the structural channels. Moessbauer spectra also indicate that the incorporation of Fe 3+ may cause a shift from deep blue to light blue colors. Based on their aquamarine composition the pegmatites were classified as barren, poor in rare alkalis (Li, Rb, Cs) and therefore little differentiated. The relatively simple mineralogy and the lack of lithium minerals such as lepidolite and spodumene confirm this classification. Thus, the composition of beryl can be used as a tracer for the prospection of pegmatites with different degrees of differentiation and consequently with different types of mineralization. (author)

  11. The origin of groundwater composition in the Pampeano Aquifer underlying the Del Azul Creek basin, Argentina

    Zabala, M.E., E-mail: mzabala@faa.unicen.edu.ar [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. Rivadavia 1917, C1033AAJ Ciudad Autónoma de Buenos Aires (Argentina); Instituto de Hidrología de Llanuras “Dr. Eduardo J. Usunoff”, Av. República Italia 780, 7300 Azul, Provincia Buenos Aires (Argentina); Manzano, M., E-mail: marisol.manzano@upct.es [Escuela de Ingeniería de Caminos, Canales y Puertos y de Ingeniería de Minas, Universidad Politécnica de Cartagena, P° de Alfonso XIII 52, E-30203 Cartagena (Spain); Vives, L., E-mail: lvives@faa.unicen.edu.ar [Instituto de Hidrología de Llanuras “Dr. Eduardo J. Usunoff”, Av. República Italia 780, 7300 Azul, Provincia Buenos Aires (Argentina)

    2015-06-15

    The Pampean plain is the most productive region in Argentina. The Pampeano Aquifer beneath the Pampean plain is used mostly for drinking water. The study area is the sector of the Pampeano Aquifer underlying the Del Azul Creek basin, in Buenos Aires province. The main objective is to characterize the chemical and isotopic compositions of groundwater and their origin on a regional scale. The methodology used involved the identification and characterization of potential sources of solutes, the study of rain water and groundwater chemical and isotopic characteristics to deduce processes, the development of a hydrogeochemical conceptual model, and its validation by hydrogeochemical modelling with PHREEQC. Groundwater samples come mostly from a two-depth monitoring network of the “Dr. Eduardo J. Usunoff” Large Plains Hydrology Institute (IHLLA). Groundwater salinity increases from SW to NE, where groundwater is saline. In the upper basin groundwater is of the HCO{sub 3}-Ca type, in the middle basin it is HCO{sub 3}-Na, and in the lower basin it is ClSO{sub 4}–NaCa and Cl–Na. The main processes incorporating solutes to groundwater during recharge in the upper basin are rain water evaporation, dissolution of CO{sub 2}, calcite, dolomite, silica, and anorthite; cationic exchange with Na release and Ca and Mg uptake, and clay precipitation. The main processes modifying groundwater chemistry along horizontal flow at 30 m depth from the upper to the lower basin are cationic exchange, dissolution of silica and anorthite, and clay precipitation. The origin of salinity in the middle and lower basin is secular evaporation in a naturally endorheic area. In the upper and middle basins there is agricultural pollution. In the lower basin the main pollution source is human liquid and solid wastes. Vertical infiltration through the boreholes annular space during the yearly flooding stages is probably the pollution mechanism of the samples at 30 m depth. - Highlights: • The

  12. Cryptic Disc Structures Resembling Ediacaran Discoidal Fossils from the Lower Silurian Hellefjord Schist, Arctic Norway.

    Christopher L Kirkland

    Full Text Available The Hellefjord Schist, a volcaniclastic psammite-pelite formation in the Caledonides of Arctic Norway contains discoidal impressions and apparent tube casts that share morphological and taphonomic similarities to Neoproterozoic stem-holdfast forms. U-Pb zircon geochronology on the host metasediment indicates it was deposited between 437 ± 2 and 439 ± 3 Ma, but also indicates that an inferred basal conglomerate to this formation must be part of an older stratigraphic element, as it is cross-cut by a 546 ± 4 Ma pegmatite. These results confirm that the Hellefjord Schist is separated from underlying older Proterozoic rocks by a thrust. It has previously been argued that the Cambrian Substrate Revolution destroyed the ecological niches that the Neoproterozoic frond-holdfasts organisms occupied. However, the discovery of these fossils in Silurian rocks demonstrates that the environment and substrate must have been similar enough to Neoproterozoic settings that frond-holdfast bodyplans were still ecologically viable some hundred million years later.

  13. The Ediacaran volcanic rocks and associated mafic dykes of the Ouarzazate Group (Anti-Atlas, Morocco): Clinopyroxene composition, whole-rock geochemistry and Sr-Nd isotopes constraints from the Ouzellarh-Siroua salient (Tifnoute valley)

    Belkacim, Said; Gasquet, Dominique; Liégeois, Jean-Paul; Arai, Shoji; Gahlan, Hisham A.; Ahmed, Hassan; Ishida, Yoshito; Ikenne, Moha

    2017-03-01

    Belonging to the huge Ouarzazate volcanic Group that covered the whole Anti-Atlas during the late Ediacaran (580-545 Ma), the Tifnoute valley volcanic formations are mainly pyroclastic and show a large composition, from trachybasalt to rhyolite and are crosscut by dolerite dykes. The Tifnoute valley volcanic rocks are located within a rigid salient of the Anti-Atlas that gives them special extreme characteristics. Due to the heavy greenschist alteration that affects this volcanic group, we focused the more immobile elements, but as REE can also be affected, we used the composition of unaltered clinopyroxene crystals to determine the nature of these volcanic rocks. The clinopyroxene is an augite diopside in the basalt, an augite in the andesite and an augite-salite in the dolerite. Petrography of the Tifnoute mafic volcanic rocks and clinopyroxene compositions indicate the presence of two magmatic series: (i) older high-K calc-alkaline (alkali-calcic) andesite and basalt characterized by the early crystallization of Fe-Ti oxides and of the late fractionation of plagioclase, the modal proportion of the latter increasing from the basalt to the andesite and (ii) younger alkalic dolerite dykes. With clinopyroxene trace element compositions obtained using laser ablation ICP-MS, we calculated the composition of the melts in equilibrium with the pyroxenes. The volcanic rocks of the Tifnoute Valley have positive εNd570 (+1.7 to +5.0), low Sri (volcanic rocks emplaced in a Pan-African transtensive post-collisional environment that evolved towards the major rifting event that will give rise to the Rheic ocean, in a similar way to what occurred just after the Variscan orogeny during the Triassic period that evolved to the Tethys ocean opening.

  14. CARACTERIZACIÓN MOLECULAR Y GERMINACIÓN DE SEMILLAS DE MAÍCES CRIOLLOS AZULES CON ENVEJECIMIENTO ACELERADO

    Dagoberto Dur\\u00E1n-Hern\\u00E1ndez

    2011-01-01

    Full Text Available El objetivo del presente estudio fue determinar el efecto del envejecimie nto acelerado en semillas de varie dades criollas de maíz azul. En los laboratorios de la Universidad Nacional Autónoma de México y del Instituto Politécnico Nacional, semillas de cuatro varie dades criollas de maíz azul (Cuijingo, Cocotitlán, Puebla y Oaxaca, se sometie ron a dos tip os de envejecimie nto acelerado: calor húmedo (41°C, 72 horas y 100% h. r. y calor seco (60°C, 48 horas. Se evaluaron: protrusión radicular de 0 a 72 horas de imbibición y, a los sie te días de incubación a 25°C, plántulas normales, anormales y semillas muertas. Se obtuvo la caracterización molecular de los tratamie ntos mediante la RA PD y se construyeron los dendogramas respectivos. En plántulas normales provenie ntes de semillas sin envejecimie nto acelerado, las varie dades Oaxaca y Puebla fueron significativamente superiores. El peso seco en las plántulas disminuyó con el deterioro, sie ndo exigua con calor seco. La presencia de plántulas anormales se incrementó con ambos tip os de deterioro en el orden: Oaxaca, Puebla, Cocotitlán y Cuijingo. La diferenciación de los perfiles de bandeo entre semillas testigo y deterioradas ocurrió con la secuencia: Oaxaca (31,6%, Cocotitlán (25,8%, Puebla (19,6% y Cuijingo (18,6%. Estos valores de similitud, a los cuales se ramificaron los perfiles genómicos, se asociaron de manera inversa con el nivel de vigor de las semillas, y directamente con la presencia de anormalidades en las plántulas obtenidas.

  15. Ediacaran ( 620 Ma) high grade regional metamorphism in the northern Arabian Nubian Shield: U/Th-Pb monazite ages of the Elat schist

    Elisha, Bar; Katzir, Yaron; Kylander-Clark, Andrew

    2017-04-01

    Ediacaran times witnessed a hemisphere-scale orogenesis forming the extensive Pan-African mountain ranges and resulting in the final assembly of Gondwana supercontinent. The Elat metamorphic basement (S Israel) located at the northernmost tip of a major Pan-African orogenic suture, the Arabian Nubian Shield (ANS), comprises amphibolite facies schists and gneisses and was most likely shaped by this major continental collision. However the timing, number and duration of metamorphic events in Elat and elsewhere in the ANS are non-conclusive and a major emphasis was given to pre-Ediacaran island-arc related tectonics. This is mostly because U-Pb dating of zircon, widely used in Elat and elsewhere, is very successful in constraining the ages of the igneous and sedimentary protoliths, but is 'blind' to metamorphism at grades lower than granulite. Here U/Th-Pb dating of monazite, a precise chronometer of metamorphic mineral growth, is systematically applied to the Elat schist and unveils the tectono-metamorphic evolution of the Elat basement. Previous U-Pb dating of detrital zircon has shown that the sedimentary protoliths of the Elat schist are the oldest basement components (≥800 Ma), and detailed structural observations of the schists portrayed a complex deformation history including four successive phases (Shimron, 1972). The earliest three phases were defined as ductile and penetrative, but some of the available geochronological data apparently contradict field relations. In-situ analysis of metamorphic monazites by LASS (Laser Ablation Split Stream) involves simultaneous measurement of U/Th-Pb isotope ratios and REE contents in a single 10 μm sized grain or domain, thus allowing determining the age of specific texture and metamorphic assemblage. Monazite dating of the Elat schist yielded two concordant age clusters at 712±6 and 613±5 Ma. The corresponding REE patterns of the dated monazite grains indicate that porphyroblast growth, either garnet or staurolite

  16. Evidence for Biogenic Iron in Ediacaran Limestones of the Yenisei Ridge Vorogovka Series (South-Western Framing of the Siberian Craton).

    Vinogradov, E.; Kosareva, L.; Metelkin, D. V.; Vishnevskaya, I.

    2017-12-01

    The composition and origin of magnetic minerals are used for reconstructing paleogeography and changes in paleoenvironments. Ediacaran limestones of the Vorogovka Series were studied in the Yenisei Ridge. Rock magnetism of the upper part of the Vorogovka Series completely depends on terrigenous admixture of iron. Non-carbonate residue consists of quartz, plagioclase, muscovite, Fe-Mg chlorite, smectite and pyrite. A prominent positive correlation is observed between the Fe content (1550…9350 ppm) and the amount of insoluble residue. Magnetization of the lower part of Vorogovka Series is due to authigenic iron. There are several indirect indications of the presence of magnetotactic bacteria and seaweed remains in these limestones. While Fe content is high (1200…8330 ppm), Fe-hydroxides, pyrite and other minerals indicating secondary transformations were not detected. Thus, iron was included in the carbonate material during sedimentation. There is no correlation between iron content and the amount of insoluble residue, which indicates that iron could not have been taken from terrigenous admixture. Study of the dependence of magnetic susceptibility from temperature in inert atmosphere (argon) revealed magnetic minerals with demagnetization temperatures of 320°C and 580°C. The former may correspond to greigite (Curie Temperature 307°C) or hexagonal pyrrhotine (325°C). The latter indicates magnetite (Curie Temperature 586°C) which may be authigenic or newly formed during the experiment. Both magnetite and greigite, are major biogenic minerals produced by magnetotactic bacteria. The main environment of modern magnetotactic bacteria is microaerophilic habitat. Therefore, their abundant presence in the Ediacaran sediments is quite natural. All of these are preliminary conclusions until bacteria can be visualized by electron microscopy, which is an ongoing. The work was supported by the Ministry of Education and Science of Russia 5.2324.2017/4.6 and the RFBR 15-05-01428.

  17. Inheritance of resistance to cotton blue disease Herança da resistência do algodoeiro à doença-azul

    Osmério Pupim Junior

    2008-05-01

    Full Text Available The objective of this work was to determine the inheritance of cotton blue disease resistance by cotton plants. Populations derived from the CD 401 and Delta Opal resistant varieties were evaluated, through a greenhouse test with artificial inoculation by viruliferous aphids. Cotton blue disease resistance is conditioned by one dominant gene, both in CD 401 and Delta Opal varieties.O objetivo deste trabalho foi determinar a herança da resistência do algodoeiro à doença-azul. Populações derivadas das variedades resistentes CD 401 e Delta Opal foram avaliadas em casa de vegetação, por meio da inoculação de pulgões virulíferos. A resistência à doença-azul do algodoeiro é condicionada por um gene dominante, tanto em 'DC 401' quanto em 'Delta Opal'.

  18. Banco de semillas en ambientes de las sierras de Azul (Buenos Aires, Argentina con distinta intensidad de disturbios Seed bank in environments of the Azul sierras (Buenos Aires, Argentina with different disturbance intensities

    F. Gianaccini

    2009-12-01

    Full Text Available A fin de evaluar el impacto de la agricultura sobre la flora potencial de pastizales serranos en el Partido de Azul (Buenos Aires, Argentina, se comparó el banco de semillas en los 20 cm superficiales del suelo entre dos sectores adyacentes en las primeras estribaciones serranas. Uno de ellos está sometido a agricultura permanente y el otro conserva un pastizal natural bajo pastoreo y quemas no programados. Este último sector presentó en promedio una densidad de 70.000 sem m-2 contra 36.720 sem m-2 en el primero. La representación de semillas de especies nativas se redujo notablemente en el ambiente agrícola. Stipa caudata con 31360 sem m-2 resultó la especie más abundante en el pastizal. En el ambiente de cultivo, su densidad se redujo a 9940 sem m-2 y fue superada por Chenopodium album con 10560 sem m-2. La similitud en la composición del banco fue de 55% en términos cualitativos y 27% en términos cuantitativos. Estos resultados evidencian que, en el área de estudio, el reemplazo del pastizal natural por agricultura reduce notoriamente las reservas de semillas y modifica la composición cualitativa y cuantitativa del banco con una elevada pérdida en la proporción de especies nativas.In order to evaluate the impact of agriculture on the potential flora of grasslands of the sierras of Azul (Buenos Aires Province, Argentina, the soil seed bank in the top 20 cm from two adjacent areas on the first foothill spurs were compared. One is submitted to continuous agriculture. The other area has grasslands under grazing and non programmed burning. The latter showed a mean density of 70.000 seeds m-2 against a mean density of 36.720 seeds m-2 in the first area. The proportional representation of native species seeds decreased strongly in the agricultural environment. The most abundant species in the grasslands was Stipa caudata (31.360 seeds m-2. In the agricultural environment, its density decreased to 9940 seeds m-2. It was surpassed by

  19. Results of the application of persistent scatterers interferometry for surface displacements monitoring in the Azul open pit manganese mine (Carajás Province, Amazon region) using TerraSAR-X data

    Pinto, Carolina d. A.; Paradella, Waldir R.; Mura, José C.; Gama, Fabio F.; dos Santos, Athos R.; Silva, Guilherme G.

    2014-10-01

    Brazil has 10% of global Mn reserves with its most important mine located in the Amazon region. The Azul deposit is related to sandstones and siltstones of the Águas Claras Formation (Archean), situated in the central portion of the Carajás Strike-Slip System. Vale S.A. mining company operates the Azul mining complex with three simultaneous excavations (mines 1, 2 and 3) conducted on rock materials of low geomechanical qualities. Mining operations are openpit, with 4-8 m-high benches and depth of 80 m. A stack of 19 TerraSAR-X (TSX) images was used for the investigation covering the period of March 20-October 4, 2012. In order to minimize the topography phase error in the interferometric process, a high resolution DEM was generated based on a panchromatic GeoEye-1 stereo pair. Persistent Scatterers Interferometry (PSI) analysis was carried out using the IPTA (Interferometric Point Target Analysis) software and led to the detection of 40,193 point-wise persistent scatterers (PS), with an average density of 5,387 PS/km2. It was concluded that most of the mining area can be considered stable during the TSX coverage. High deformation rates related to settlements were mapped over a waste pile, while small deformation rates were detected along the north and south flanks of mine 1and were interpreted as cut slope movements toward the center of the pit. Despite only ground-based radar measurements were available for a short time period during the TSX coverage, and covering a sector of bench walls along the south flank of mine 1, the PSs movement patterns showed concordance with the field measurements. The investigation emphasized the important role that PSI technique can play in planning and risk assessment in this mining area. Monitoring of this type of deformation by PSI can usefully complement other commonly used field geotechnical measurements due to the synoptic SAR coverage over a dense grid, providing ground deformation data independently of field access and with

  20. Cromoendoscopia com azul de metileno para diagnóstico de esôfago de Barrett

    Saporiti Marcela Rocha Loures

    2003-01-01

    Full Text Available RACIONAL: O esôfago de Barrett é uma condição na qual a mucosa escamosa esofágica é substituída por metaplasia intestinal especializada, que predispõe o paciente ao desenvolvimento de adenocarcinoma esofágico. Este é precedido por displasia e carcinoma precoce; o rastreamento dessas lesões faz-se através de endoscopias digestivas periódicas com biopsias randomizadas. A incidência aumentada desse, tem despertado interesse no desenvolvimento de novas técnicas endoscópicas, como a cromoendoscopia com azul de metileno, para melhorar a identificação do esôfago de Barrett e suas complicações. OBJETIVO: Determinar se as biopsias dirigidas pela cromoendoscopia com azul de metileno oferecem vantagem em relação ao método convencional na detecção do esôfago de Barrett. MATERIAL E MÉTODO: Estudaram-se 45 pacientes com diagnóstico prévio de esôfago de Barrett, todos submetidos a dois exames de endoscopia digestiva alta com biopsias, em intervalo de 4 semanas, um convencional e outro com aplicação do corante, no período entre abril e outubro de 2002. RESULTADOS: Os resultados histológicos das biopsias de todos os exames foram comparados. Observou-se sensibilidade de 62,5%, especificidade de 15,4%, valor preditivo positivo de 57,7% e valor preditivo negativo de 18,2%. Não houve diferença significativa quanto ao número de biopsias. O tempo de duração da técnica de cromoendoscopia foi significativamente maior quando comparado ao da técnica convencional. CONCLUSÃO: Não se observou vantagem na utilização da cromoendoscopia em relação à técnica randomizada no diagnóstico do esôfago de Barrett.

  1. Application of a Box-Behnken design for optimizing the extraction process of agave fructans (Agave tequilana Weber var. Azul).

    Flores-Girón, Emmanuel; Salazar-Montoya, Juan Alfredo; Ramos-Ramírez, Emma Gloria

    2016-08-01

    Agave (Agave tequilana Weber var. Azul) is an industrially important crop in México since it is the only raw material appropriate to produce tequila, an alcoholic beverage. Nowadays, however, these plants have also a nutritional interest as a source of functional food ingredients, owing to the prebiotic potential of agave fructans. In this study, a Box-Behnken design was employed to determine the influence of temperature, liquid:solid ratio and time in a maceration process for agave fructan extraction and optimization. The developed regression model indicates that the selected study variables were statistical determinants for the extraction yield, and the optimal conditions for maximum extraction were a temperature of 60 °C, a liquid:solid ratio of 10:1 (v/w) and a time of 26.7 min, corresponding to a predicted extraction yield of 37.84%. Through selective separation via precipitation with ethanol, fructans with a degree of polymerization of 29.1 were obtained. Box-Behnken designs are useful statistical methods for optimizing the extraction process of agave fructans. A mixture of carbohydrates was obtained from agave powder. This optimized method can be used to obtain fructans for use as prebiotics or as raw material for obtaining functional oligosaccharides. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  2. Polymorphism and methylation patterns in Agave tequilana Weber var. 'Azul' plants propagated asexually by three different methods.

    Díaz-Martínez, Miriam; Nava-Cedillo, Alejandro; Guzmán-López, José Alfredo; Escobar-Guzmán, Rocío; Simpson, June

    2012-04-01

    Genetic variation in three forms of asexually propagated Agave tequilana Weber var. 'Azul' plants namely offsets, bulbils and in vitro cultured individuals was studied by AFLP analysis. Low levels of variation were observed between mother plants and offsets and a higher level between mother plant and bulbils. Families obtained from commercial plantations showed lower levels of variation in comparison to families grown as ornamentals. No variation was observed between the original explant and four generations of in vitro cultured plants. Epigenetic variation was also studied by analyzing changes in methylation patterns between mother plants and offspring in each form of asexual reproduction. Offsets and bulbils showed an overall decrease in methylation whereas in vitro cultured plants showed patterns specific to each generation: Generations 1 and 4 showed overall demethylation whereas Generations 2 and 3 showed increased methylation. Analysis of ESTs associated with transposable elements revealed higher proportions of ESTs from Ty1-copia-like, Gypsy and CACTA transposable elements in cDNA libraries obtained from pluripotent tissue suggesting a possible correlation between methylation patterns, expression of transposable element associated genes and somaclonal variation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Water level effect on herbaceous plant assemblages at an artificial reservoir-Lago Azul State Park, Southern Brazil

    D. C. Souza

    Full Text Available This study presents the effect of water level variation on the assemblages of herbaceous species in Mourão I Reservoir, Lago Azul State Park, Southern Brazil. The structure and distribution of populations was examined in February (dry period and April (rainy period, 2011, in two transects. These transects started at the forest edge towards the center of the lake. The end of the transect coincided with the end of the plants within the lake. On every two meters along of the transects we sampled a wooden square of 0.25 m2 for species biomass analysis.The macrophyte stand was composed entirely of emergent species. Considering the periods, most species were less frequent in the rainy period (April, but Ipomea ramosissima (Poir. Choisy, Commelina nudiflora L., Eleocharis acuntagula (Roxb. Schult. and Verbena litorales (Kunth. had their frequency increased during this period, probably due to their resistance. The influence of flood as measured by the NMDS point out that both before and after the flood, there are plots with distinct compositions and biomass. The water level variation affects the dynamics of plant composition and structure in marginal areas of the Reservoir.

  4. The blue land planarian Caenoplana coerulea, an invader in Argentina La planaria terrestre azul Caenoplana coerulea, un invasor en Argentina

    Lisandro Héctor Luis-Negrete

    2011-03-01

    Full Text Available The blue land planarian Caenoplana coerulea is reported from Argentina (Buenos Aires province. We found C. coerulea in the east central region of Argentina in anthropic environments. The specimens that we found have the characteristic of the species found in others regions; that is, a bluish dorsal surface with a yellow mid-dorsal stripe and eyes forming a single row around the anterior tip, clustered laterally. This is the first record of this species from the Neotropical Region, and together with Bipalium kewense are the only 2 species of exotic terrestrial planarians so far recorded in Argentina.La planaria terrestre azul Caenoplana coerulea se registra para el centro este de Argentina (provincia de Buenos Aires, en ambientes antropizados. Los ejemplares encontrados presentan las características de la especie registrada en otras regiones, con una superficie dorsal azulada y una hilera medio dorsal amarilla, y ojos formando una hilera alrededor del extremo anterior, agrupados lateralmente. Es la primera vez que se cita dicha especie en la Región Neotropical, y junto a Bipalium kewense son las únicas planarias terrestres exóticas registradas en Argentina.

  5. Argyria mimicking a blue nevis: dermoscopy features Argyria imitando um nevo azul: características dermatoscópicas

    Maria Leonor Enei

    2013-06-01

    Full Text Available Argyria is a rare disease caused by prolonged skin contact with silver. Localized cases have been described regarding the use of topical medications, and trauma with objects containing this metal such as acupuncture needles and jewelry. Clinically, a macule or a patch, round or oval, appears in the infected area, with a characteristic bluey-gray color. To our knowledge this is the first time that this clinical condition has been described through the use of dermoscopy.A argíria é uma doença rara, causada pelo contato prolongado da pele com prata. Foram descritos casos localizados relacionados ao uso de medicamentos tópicos e traumas com objetos que contem esse metal, como agulhas de acupuntura e jóias, por exemplo. Clinicamente, aparecem máculas ou manchas redondas ou ovais na área afetada, com uma característica cor azul-acinzentada. Até onde sabemos esta é a primeira vez que este quadro clínico foi descrito através da dermatoscopia.

  6. Suicidio en azul con negra mancha. Breve historia de un balazo en la pintura de Pablo Picasso

    Godoy C., Ivan

    2013-12-01

    Full Text Available Paris 1901: unrequited love drove Carles Casagemas, a close friend of Pablo Picasso’s youth, to commit suicide by shooting himself in the head. This tragic event was a major blow to Picasso, causing him to dwell upon the subject of death and express his “mourning” through his paintings. The “bullet hole” in his friend’s temple symbolically displaced several areas of the young Picasso’s life and became a “deep vacuum” and “melancholy”, permeating various areas in Picasso’s paintings, and marking the start of his famous blue period.París 1901: por el amor de una mujer, se suicida de un balazo en la cabeza Carles Casagemas, amigo íntimo de juventud de Pablo Picasso. Este trágico suceso producirá un gran dolor en el artista, el cual, lo hará internarse en el tema de la muerte y elaborar su “duelo” apoyado en su pintura. El “hoyo a bala” en la sien de su amigo se desplazará simbólicamente a varios espacios de la vida del joven Picasso y devendrá en “vacío profundo” y “melancolía”, permeando diferentes ámbitos dentro de la pintura de Picasso, dando comienzo a su mentado período azul.

  7. The benthonic macro invertebrates of Pozo Azul (Gaira River basin, Colombia) and their relationship with water quality

    Guerrero Bolano, Francisco; Manjares Hernandez, Ana; Nunez Padilla, Norbelis

    2003-01-01

    On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macro invertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River Basin, Magdalena, Colombia). The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were found 588 individuals distributed in 11 orders and 38 families. The most representative orders were trichoptera, coleoptera, diptera and ephemeroptera. The most representative families were baetidae, simullidae, perlidae, chironomidae, and hydropsychidae, in this rank of abundance. The BMWP index for the relationship between the community structure and the water quality (adapted by Universidad del Valle, Cali, Colombia) was calculated. According to this index the water quality was optimum. Also, given the general characteristics of the site studied, the water mass quality was classified as good and oligosaprobit, based on the saprobit ecology. It is possible that this state was reached due to stabilization after a small perturbation induced by coffee cultivation in the zone

  8. El secreto del huevo azul, de Catalina González Vilar. Estudio narratológico

    Miguel Sánchez-García

    2013-01-01

    Full Text Available Este trabajo aborda el estudio narratológico de la obra El secreto del huevo azul , de la escritora Catalina González Vilar, que obtuvo el Premio El Barco de Vapor en el año 2012. Examina los diferentes elementos constitutivos del texto (el enfoque del tema, la caracterización de los personajes, la estructura sintáctica, el tratamiento del lenguaje, la técnica narrativa utilizada... y su aporte al desarrollo de la historia con la finalidad de descubrir los valores estéticos y literarios que aporta a la fábula. Pretende demostrar el adecuado uso de todos ellos dado que favorecen un texto rico en matices, llamativo, sugerente. Cualidades, todas ellas, de gran importancia tanto en creaciones destinadas al público adulto como al infantil y juvenil pues enriquece el valor final de la obra, y por extensión, el bagaje cultural de sus lectores.

  9. Composicion y variabilidad espacialdel banco de semillas de malezas en un area agricolade azul (Argentina Composition and spatial variation of a weed seed bank on an agricultural area in Azul, Argentina

    Eduardo Requesens

    1999-08-01

    Full Text Available No Distrito Azul, zona central da província de Buenos Aires (Argentina, encontram-se ambientes de planície na parte norte e ambientes serranos na parte sul. Esta última, constituí-se numa área predominantemente agrícola, onde a cultura de trigo, principal atividade agrícola, se alterna com culturas de verão como milho, girassol e soja. Com o objetivo de caracterizar globalmente o banco de sementes da área agrícola, foram analisados o conteúdo de sementes, a composição de espécies, a distribuição e variabilidade espacial das espécies que o compõem. A informação básica foi obtida aplicando-se a técnica da emergência em amostras de solo correspondentes a 20 locais alinhados numa faixa de 14 km. A densidade de sementes nos locais de amostragem variou entre 1.173 e 44.000 sem/m2. Na totalidade, foram detectadas 33 espécies. Digitaria sanguinalis foi claramente a espécie dominante, aportando com quase 43 % do banco, seguida de Polygonum aviculare com um aporte de 15 %. As duas espécies, juntamente com Anagallis arvensis e Setaria viridis completam70 % do banco de sementes. A composição específica completa-se com um grupo de 29 espécies, os quais contribuem, cada um delas, com menos de 5%. A distribuição espacial das espécies ao longo da faixa estudada mostrou um grau de agregação variável, sendo encontrada uma correlação positiva significativa entre o tamanho do banco e a relação variância/média. Demonstrou-se, assim, que as espécies mais abundantes em média, apresentaram grande variabilidade espacial. Nelas, foram observados diferentes padrões de distribuição espacial.Azul, in the center of the Province of Buenos Aires (Argentina, includes flat environments in the north and hill environments in the south. Last constitutes a predominantly agricultural area where the wheat crop, principal activity, alternates with summer crops as corn, sunflower and soybean. The objetive of the present paper is to

  10. MICROPROGAPACIÓN DE AGAVE (Agave tequilana Weber. var. Azul A TRAVÉS DE YEMAS AXILARES

    A. Angeles-Espino

    2012-12-01

    Full Text Available El agave (Agave tequilana Weber var. azul, se le conoce comúnmente como “Agave Azul o Agave Tequilero”. La planta de agave es un producto económicamente importante de México debido a que es el ingrediente base del Tequila, el cual es una bebida popular destilada. La micropropagación es una técnica importante para la multiplicación masiva en agave y la respuesta a los reguladores de crecimiento debe considerarse en el desarrollo de cada protocolo. El objetivo del trabajo fue obtener plántulas de agave a partir del cultivo de meristemos in vitro. Se colectaron hijuelos de seis meses en plantaciones de 3 años de edad. Los meristemos se lavaron y desinfestaron con alcohol al 70% y una solución de hipoclorito al 3% por 15 minutos y se dio triple enjuague en condiciones de asepsia en la cámara de flujo laminar. Los explantes se sembraron en el medio Murashige y Skoog (MS, suplementado con 24.6 µM de AIB y 46.46 μM de Cinetina, 30 g/L de sacarosa y 8 g/L de agar para su solidificación. El medio se vertió en frascos de 100 mL de capacidad a razón de 25 mL y se esterilizó en autoclave por 15 min a 121°C. Se sembró un explante por frasco y se colocaron en la cámara de crecimiento a 27°C con 16 horas luz. La inducción de los brotes se presentó a partir de la cuarta semana posterior a la siembra. Los brotes obtenidos se multiplicaron transfiriéndose a medio MS suplementado con 0.1 mg L-1 de AIB y 46.46 μM de Cinetina. El desarrollo de las plántulas se obtuvo a la cuarta semana después del inicio de la inducción de los brotes. La micropropagación de plántulas de agave a partir de yemas axilares, se completó en un lapso de 10 semanas a partir de la siembra de los meristemos. Al considerar el tiempo requerido para la obtención de vitroplántulas de agave, se confirmó que la técnica de micropropagación es un proceso eficiente para la obtenci

  11. PROPAGACIÓN ASEXUAL DE AZUL DE MATA (Justicia tinctoria (OERST. D. N. GIBSON, FAM. ACANTHACEAE POR MEDIO DE ESTACAS

    Carlos A. Solís

    2015-01-01

    Full Text Available Se evaluó el efecto de dosis de ácido indolbutírico (0, 500, 1000 o 1500 ppm, la posición de donde se toma la estaca (basal, medial o terminal, el tamaño de la estaca (6, 10 o 14 cm, la ausencia o presencia de hojas, y el tipo de sustrato (arena de río, fibra de coco o carbón de granza de arroz, sobre el enraizamiento de estacas de azul de mata bajo ambiente protegido. Las variables evaluadas fueron el porcentaje de brotación y de enraizamiento, número de brotes, cantidad y longitud de raíces. Las estacas terminales presentaron los mayores valores para todas las variables, excepto porcentaje de enraizamiento: mayor número de brotes (17,5, longitud (0,17 y cantidad de raíces (0,65 que las estacas mediales y basales, lo que estaría asociado a una mayor velocidad de enraizamiento. Las dosis de AIB 1000 y 1500 ppm indujeron una mayor cantidad de raíces por estaca (8,40 y 9,24 respectivamente que las dosis menores. Hubo mayor porcentaje de enraizamiento con 1000 ppm de AIB (69% que sin ese compuesto (41%. Al utilizar estacas sin hojas aumentó la magnitud de cada una de esas variables. Con arena se obtuvo una mayor brotación aérea (96%, enraizamiento (92% y longitud de raíz (5,1 cm que con los otros sustratos. Las estacas de 14 cm presentaron consistentemente, mayor número de brotes (3,71, raíces más largas (3,56 cm y en mayor número (10,71 que las de 10 y 6 cm.

  12. Uso de Materiais Alternativos em Processos de Adsorção de Corante Azul de Metileno

    E. L. do Rego

    2014-11-01

    Full Text Available Este trabalho teve como objetivo empregar materiais alternativos, puros e/ou modificados com 5 ou 10% (m/m de  pentóxido de nióbio (Nb2O5, em processos de remoção de azul de metileno (AM. Entre os materiais alternativos foram utilizadas argila sanitária, argila de resíduo industrial, rochas sedimentares e cinzas de casca de arroz obtida pela queima a 350oC. Estes sólidos foram caracterizados pelas técnicas de difração de raios- X (DRX e espectroscopia na região do infravermelho (FTIR. Os testes de remoção de AM foram realizados em frascos de 125 mL, sob agitação constante, contendo 100 mL de solução de AM (100mg/L a 2000mg/L e adsorvente (0,1 a 0,6g, sob uma mesa agitadora a 200 rpm, em temperatura ambiente. A quantificação da remoção de AM foi realizada com auxílio de um espectrofotômetro UV-Vis da Varian (Cary 50, coletando 2 mL de amostra nos períodos de 2 à 1440 min. Dados de DRX evidenciaram uma mistura de argilominerais nos sólidos baseados em argilas. Nos ensaios de adsorção os materiais demonstraram eficiência para a remoção do corante, com destaque aqueles modificados com 10% de Nb2O5 exibindo 95% de remoção, no tempo de 120min, em solução de pH de ~6,5.

  13. Uso do corante azul de metileno a 2% na localização do linfonodo axilar em cadelas (Canis familiaris – Linnaeus, 1758

    Tábata Maués

    2016-04-01

    Full Text Available A biopsia de linfonodo sentinela (LS é cada vez mais utilizada para a determinação do estadiamento clínico tumoral. O acometimento de linfonodos em animais com doença oncológica possui forte valor prognóstico no tumor da glândula mamária. Em medicina veterinária faltam diretrizes bem estabelecidas para a avaliação do LS. O objetivo deste estudo foi avaliar a eficácia do corante azul de metileno a 2% na identificação do linfonodo axilar em cadelas com lesões mamárias. Para tanto, foram utilizadas 101 cadelas, portadoras de lesões mamárias, submetidas à mastectomia radical unilateral ou bilateral. Antes do início da cirurgia, aplicou-se, por via intradérmica, na área ao redor da mama torácica cranial, solução de azul de metileno a 2% estéril. O corante foi eficaz na identificação do linfonodo axilar em 76,27% das cadeias mamárias. Obtiveram-se estruturas coradas em azul, semelhantes a linfonodos em 78,81% dos casos. Dessas estruturas, 96,77% foram confirmadas ao exame histopatológico como linfonodos. Dada a importância prognóstica do comprometimento de linfonodos em alguns tumores, a avaliação do LS deve ser incorporada à rotina clínica, de modo a permitir um estadiamento mais preciso das cadelas com neoplasia mamária.

  14. Efectividad del Caldo Lactosado con Azul de Bromotimol en el control bacteriológico de las desinfecciones profilácticas en instalaciones bovinas

    Cepero Rodríguez, Omelio:; Silveira Prado, Enrique A.:; Suárez Fernández, Yolanda E.:; González García, Oraida:

    2008-01-01

    Con la finalidad de evaluar la efectividad del medio de cultivo CaldoLactosado con Azul de Bromotimol (CLAB) en el control bacteriológico de las desinfecciones profilácticas se realizó un estudio en unidades bovinas cuyos resultados se compararon en paralelo con los obtenidos con el medio de Heifetz Modificado (HM), establecido en Cuba para esta actividad. Previa limpieza mecánica se aplicaron las soluciones desinfectantes mediante una unidad móvil y después de tres horas de exposición se rea...

  15. Levantamento das Cianobactérias Psâmicas em Sedimentos Superficiais Marginais da Lagoa Azul, Arraial do Cabo, Rio de Janeiro.

    Loreine Hermida da Silva e Silva; Anderson Andrade Cavalcanti Iespa; Cynthia Moreira Damazio Iespa; Teresa Cristina Lopes Medeiros Faruolo

    2008-01-01

    The coastal area of the Rio de Janeiro State presents a series of lagoons, dune fi elds and strand plains, which are the result of thepaleogeographical evolution during Neogene. The lagoa Azul is situated at 22o56’52”S and 42o04’62”W in the Arraial do Cabo, locatedabout 160 km far the city of Rio de Janeiro. It is a natural hypersaline coastal aquatic body which, parallel to Atlantic Ocean. The presentwork focused on the identifi cation of psammic cyanobacteria in the surface sediments of the...

  16. Comportamiento electroquímico de colorantes antraquinónicos, azul de metileno, y compuestos afines en solución de solventes no-acuosos

    Martínez Suárez, Jaime Fernando

    2017-01-01

    El trabajo realizado en esta Tesis doctoral pretende contribuir a la electroquímica orgánica, particularmente, en el campo del comportamiento electroquímico de colorantes en solución de solventes no acuosos. Se estudia por voltamperometría cíclica (VC) el comportamiento de los colorantes azul de metileno, alizarina, purpurina, ácido carmínico, quinalizarina y rojo de alizarina S, y además un precursor para la síntesis de colorantes indigoides, la isatina. El comportamiento electroquímico de l...

  17. Efecto de la plata sobre el proceso de síntesis por fusión de un pigmento del tipo azul ultramarino

    Castillo, Wilmer; González, Luis; Sánchez, Selene; Ocanto, Freddy; Linares, Carlos F

    2011-01-01

    Se realizó la síntesis de pigmentos inorgánicos del tipo azul ultramarino a partir de la mezcla de zeolita A, carbonato de sodio, azufre elemental y contenido de plata entre un 0 al 5% p/p a una temperatura de 800°C por espacio de 4h. Los sólidos fueron caracterizados por la técnicas de difracción de rayos X (DRX), infrarrojo con transformada de Fourier (FTIR) y espectroscopia de reflectancia de UV a fin de verificar la estructura y coloración de los materiales obtenidos. Los resultados mostr...

  18. A ESTRATÉGIA DO OCEANO AZUL: UM ESTUDO DE CASO EM UMA EMPRESA DE SERVIÇOS NA CIDADE DE CAMPINA GRANDE – PB

    Xavier, Leandro Correia; Parque Tecnológico da Paraíba (PaqTec/PB); Barbosa, Robson Fernandes; Universidade Federal de campina Grande - UFCG; Sousa, Jackson Epaminondas de; Universidade Federal de Campina Grande - UFCG; Barbosa, Diego Fernandes; INFRAERO; Alexandre, Stefane Nogueira; UFCG

    2015-01-01

    As empresas se utilizam de estratégias e atitudes para chegar a um determinado objetivo, observando os pontos fortes e fracos do ambiente interno e externo da organização. Assim, têm-se a teoria do trade-off (valorXcusto) no qual as empresas sempre optam por um de dois caminhos: agregar valor ao produto para cobrar mais, ou o cobrar menor preço com um produto menos diferenciado. Hoje, emerge no mundo científico um novo paradigma, a estratégia do oceano azul, a qual afirma que é possível as em...

  19. Historical review of the sanitary filling of Rio Azul and considerations about heavy metals treated in it and the presents in our homes

    Mora Chinchilla, Rolando; Mora Amador, Raul

    2003-01-01

    A summary has been done on the most outstanding events during the history of Rio Azul sanitary landfill by consultating documents and local newspapers. The historical outline starts in 1972, when the Inter municipal Cooperative Agreement (COCIM) was created, until May 27, 2002, when a warning was issued on the possible harmful effects on health due to technological waste disposal. Likewise, the method for estimating the mass of metals deposited in the landfill is disclosed. In this landfill the mass of metals varies between 70000 and 100000 tm. Finally, some considerations on household chemical products are made and recommendations are presented to improve metal waste management. (Author) [es

  20. U-Pb geochronology and paleomagnetism of the Neoproterozoic St Simeon dolerite dykes, Quebec: an eastern Laurentian perspective of Ediacaran Rodinia breakup

    Pisarevsky, Sergei; Murphy, Brendan; Hamilton, Mike; Söderlund, Ulf; Hodych, Joseph

    2013-04-01

    The St Simeon (SS) mafic dykes (150 km NE of Quebec City) are now dated at 548 ± 1 Ma (U-Pb; baddeleyite). This age is similar to a published LA-ICPMS zircon age of 550 ± 7 Ma for the Mt. St-Anselme (MS) basalts, which supports previous inferences of (i) a genetic relationship between them, (ii) the pene-contemporaneity of OIB-type mafic magmatism in East Laurentia and (iii) the existence of two late Ediacaran plumes that attended the final breakup of Rodinia and opening of the Iapetus Ocean and Tornquist Sea. Both the SS dykes and the MS basalts were sampled for paleomagnetic study. The paleomagnetic pole for SS is similar to the previously published pole for coeval basalts (Skinner Cove, SC) from Newfoundland. Unlike SC, the St Simeon pole represents rocks which are unambiguously coherent tectonically with the Laurentian Craton. This new pole is also coeval with high quality poles from the Winter Coast (Baltica) and provides paleomagnetic constraints on the history of the final breakup of Rodinia and opening of Eastern Iapetus and Tornquist Sea.

  1. Avaliação biomecânica do cimento ortopédico combinado com antibiótico e azul de metileno Biomechanical evaluation of orthopaedic cement combined with antibiotic and methylene blue

    Marcos Felipe Marcatto de Abreu

    2009-01-01

    Full Text Available OBJETIVO: O cimento acrílico é utilizado há anos nas cirurgias ortopédicas, especialmente nas artroplastias do joelho, merecendo atenção também quando utilizado com o acréscimo de antibióticos (para tratamento de infecções ou corantes (para facilitação de uma possível retirada. Neste estudo procurou-se avaliar diferenças mecânicas entre o cimento ortopédico puro e quando misturado com antibiótico e/ou corante. MÉTODOS: Foram utilizados cimento acrílico ortopédico Surgical Simplex®P Stryker, vancomicina em pó e azul de metileno e as misturas submetidas a testes físicos e mecânicos de acordo com a norma ABNT NBR ISO 5833. Avaliou-se: tempo para a formação de massa, capacidade de intrusão, resistência à compressão, resistência ao dobramento (tensão e temperatura máxima atingida pelas misturas. RESULTADOS: As misturas avaliadas foram aprovadas quanto ao tempo de preparação da mistura, temperatura máxima alcançada, profundidade da intrusão e resistência à compressão. Somente aquela contendo apenas cimento puro foi aprovada no ensaio de flexão. CONCLUSÃO: O acréscimo de vancomicina e/ou azul de metileno ao cimento ortopédico Surgical Simplex®P Stryker reduz a resistência da mistura à flexão, sendo reprovada pela norma ABNT NBR ISO 5833.OBJECTIVE: Acrylic cement has been used for years on orthopaedic surgeries, especially on knee arthroplasties, deserving special attention when added to antibiotics (for treatment of deep bone infections or stains (to facilitate its removal. The present study was conducted in order to evaluate potential mechanical differences between the orthopaedic cement itself and when this is added to antibiotic and/or stains. METHODS: Surgical bone cement Simplex®P Stryker, vancomycin and methylene blue were used, and the mixtures were submitted to physical and mechanical tests according the ABNT NBR ISO 5833 rule. The parameters studied here were: time for mass formation

  2. Agave azul y el desarrollo sustentable en la cuenca baja del río Ayuquila, Costa Sur de Jalisco (1994-2004

    Peter R.W. Gerritsen

    2011-01-01

    Full Text Available El agave azul (Agave tequilana Weber es un cultivo nuevo para la cuenca del río Ayuquila en la Costa Sur de Jalisco, y es importante para su progreso agropecuario. Sin embargo, se observan efectos socioambientales negativos. Desde 2003 se han estudiado las condiciones del cultivo y su expansión, así como alternativas posibles. Los resultados muestran un crecimiento acelerado desde su introducción, a mitad de la década de 1990. Se destaca una concentración de propietarios privados y a través de contratos. Si bien sembrar esta planta puede ser redituable, las tendencias cíclicas de sobreproducción y escasez han originado una falta de incentivos para hacerlo y un deterioro de la capacidad productiva. Se discuten las perspectivas del avance agropecuario basado en el cultivo del agave azul, y se ofrecen algunas recomendaciones para fomentar la sustentabilidad de su sistema de producción comercial.

  3. Levantamento das Cianobactérias Psâmicas em Sedimentos Superficiais Marginais da Lagoa Azul, Arraial do Cabo, Rio de Janeiro.

    Loreine Hermida da Silva e Silva

    2008-05-01

    Full Text Available The coastal area of the Rio de Janeiro State presents a series of lagoons, dune fi elds and strand plains, which are the result of thepaleogeographical evolution during Neogene. The lagoa Azul is situated at 22o56’52”S and 42o04’62”W in the Arraial do Cabo, locatedabout 160 km far the city of Rio de Janeiro. It is a natural hypersaline coastal aquatic body which, parallel to Atlantic Ocean. The presentwork focused on the identifi cation of psammic cyanobacteria in the surface sediments of the lagoa Azul. The samples were obtained byusing plastic tubes and were later aconditiones in opaque plastic containers and conserved in a 4% solution of formaldehyde. With thematerial obtained, permanent slides were prepared so as to characterize them phycologically. Qualitative analysis showed the presenceof 14 species and the occurrence of the families Chroococcaceae Nägeli 1849 (5 sp., Phormidiaceae Anagnostidis & Komárek 1988(4 sp., Synechococcaceae Komárek & Anagnostidis 1995 (2 sp., Nostocaceae Kützing 1843 (1 sp., Oscillatoriaceae Gomont 1892(1 sp. and Pseudanabaenaceae Anagnostidis & Komárek 1988 (1 sp.. The incidence of these species is also recorded in other lagoons(Araruama, Pernambuco, Pitanguinha and Vermelha in the northeast of Rio de Janeiro coast, such as the frequency of cyanobacteriais justifi ed by the harsh environment, without predation, with high salinity, elevated temperature and low concentration of oxygen.

  4. Magnetic fabric and flow direction in the Ediacaran Imider dyke swarms (Eastern Anti-Atlas, Morocco), inferred from the Anisotropy of Magnetic Susceptibility (AMS)

    Otmane, Khadija; Errami, Ezzoura; Olivier, Philippe; Berger, Julien; Triantafyllou, Antoine; Ennih, Nasser

    2018-03-01

    Located in the Imiter Inlier (Eastern Saghro, Anti-Atlas, Morocco), Ediacaran volcanic dykes have been studied for their petrofabric using Anisotropy of Magnetic Susceptibility (AMS) technique. Four dykes, namely TF, TD, FF and FE show andesitic compositions and are considered to belong to the same dyke swarm. They are oriented respectively N25E, N40E, N50E, and N10E and have been emplaced during a first tectonic event. The dyke FW, oriented N90E displays a composition of alkali basalt and its emplacement is attributed to a subsequent tectonic event. These rocks are propylitized under greenschist facies conditions forming a secondary paragenesis constituted by calcite, chlorite, epidote and sericite. The dykes TF, TD, FF and FE are sub-volcanic calc-alkaline, typical of post-collisional basalts/andesites, belonging to plate margin andesites. The FW dyke shows a within-plate basalt signature; alkaline affinity reflecting a different petrogenetic process. The thermomagnetic analyses show a dominantly ferromagnetic behaviour in the TF dyke core carried by single domain Ti-poor magnetite, maghemite and pyrrhotite. The dominantly paramagnetic susceptibilities in TF dyke rims and TD, FE, FF and FW dykes are controlled by ilmenite, amphibole, pyroxene and chlorite. The magnetic fabrics of the Imider dykes, determined by our AMS study, allows us to reconstitute the tectonic conditions which prevailed during the emplacement of these two generations of volcanic dykes. The first tectonic event was characterized by a roughly NE-SW compression and the second tectonic event is characterized by an E-W shortening followed by a relaxation recording the end of the Pan-African orogeny in the eastern Anti-Atlas.

  5. Ediacaran to Cambrian magmatic suites in the Rio Grande do Norte domain, extreme Northeastern Borborema Province (NE of Brazil): Current knowledge

    do Nascimento, Marcos Antonio Leite; Galindo, Antonio Carlos; de Medeiros, Vladimir Cruz

    2015-03-01

    The Ediacaran-Cambrian plutonic activity is one of the most important geological features of the Rio Grande do Norte Domain (Borborema Province, NE Brazil). It is represented by several batholiths, stocks and dykes. Based on the petrographic, geochemical and geochronological characteristic of different rocks, this plutonic activity can be grouped in six separate suites: shoshonitic (Shos), porphyritic high-K calc-alkaline (PHKCalcAlk), equigranular high K calc-alkaline (EHKCalcAlk), calc-alkaline (CalcAlk), alkaline (Alk) and charnockitic alkaline (ChAlk). Geochemically, the Shos, CalcAlk and Alk suites are differentiated from the others, while ChAlc can be distinguished from the others in some diagrams. The greatest difficulty lies in distinguishing between the chemically similar PHKCalcAlk and EHKCalcAlk. To this end, existing geochronological data as well as related petrographic and textural field aspects may be used to distinguish the two mentioned suites (PHKCalcAlk and EHKCalcAlk). Petrographically, the Shos suite has composition between gabbro/diorite and quartz monzonite. Monzogranites (with subordinate granodiorites and quartz monzonites) predominate in both PHKCalcAlk and EHKCalcAlk. Calc is composed of granodiorites to tonalites. Alc is formed by alkali feldspar granites (with subordinate alkali feldspar quartz syenites and syenogranites), whereas ChAlc has quartz mangerites and charnockites. The suites were emplaced between the Ediacaran (635-541 Ma) and Cambrian (541-485 Ma), predominantly in the Ediacaran, based on 34 U-Pb datings (zircon, titanite, monazite and columbite-tantalite), 17 Rb-Sr (whole rock) and 1 Sm-Nd (total rock and mineral) internal isochrons. The Shos suite has U-Pb ages varying from 599 ± 16 (Poço Verde pluton) to 579 ± 7 (Acari and São João do Sabugi plutons), slightly older than those of the PHKCalcAlk suite, which ranges between 591 ± 4 Ma (Totoró pluton) and 544 ± 7 Ma (São José de Espinharas pluton). The Calc

  6. A ESTRATÉGIA DO OCEANO AZUL: UM ESTUDO DE CASO EM UMA EMPRESA DE SERVIÇOS NA CIDADE DE CAMPINA GRANDE – PB

    Leandro Correia Xavier

    2015-09-01

    Full Text Available As empresas se utilizam de estratégias e atitudes para chegar a um determinado objetivo, observando os pontos fortes e fracos do ambiente interno e externo da organização. Assim, têm-se a teoria do trade-off (valorXcusto no qual as empresas sempre optam por um de dois caminhos: agregar valor ao produto para cobrar mais, ou o cobrar menor preço com um produto menos diferenciado. Hoje, emerge no mundo científico um novo paradigma, a estratégia do oceano azul, a qual afirma que é possível as empresas optarem, de uma só vez, pela diferenciação e pela liderança em preços. Este trabalho visa verificar a relação entre a estratégia do oceano azul com a adotada por uma empresa de serviços de pesquisa e intermediação de compras de mantimentos, que concorre com supermercados, ofertando os mesmos produtos, porém, de forma inovadora com este tipo de comercialização na cidade de Campina Grande-PB, através da compra pela internet. Trata-se de um estudo de caso aplicado aos principais supermercados do município e para tratamento dos dados utilizou-se da abordagem quali-quantitativa. Foi analisada a percepção do cliente e feito a matriz de avaliação de valor, tanto do setor de atuação quanto da empresa estudada. Concluiu-se, que a estratégia adotada está alinhada com a estratégia de oceano azul, pois, igualmente aos supermercados, a empresa estudada supre a necessidade dos clientes, todavia, sem utilizar estoques, com entrega em domicílio e atendimento personalizado, tudo isto sem acrescentar maiores custos ao consumidor final, liderando em preços ao passo que se diferencia da concorrência.

  7. Técnicas de empleo del azul de metileno para la caracterización de finos en materiales de ingeniería

    Jorge Luis Rodríguez González

    2010-12-01

    Full Text Available Elempleo del azul de metileno en ingeniería se inició en  Francia  a  finales  de  los  años  ochenta,  con  la finalidad de caracterizar la actividad y naturaleza de los  finos  contenidos  en  las  arenas  y gravas  que  se empleaban  en  la  fabricación  de  concretos; posteriormente  se  desarrollaron  variantes  de  dicho empleo  para determinar  la  presencia  de  arcillas  en los finos de tamaños inferiores a 400 micras, para su empleo en materiales de bases, subbases y mezclascomplemento  al  ensayo  de  equivalente  de  arena,asfálticas.  En Colombia  existe  actualmente  una tendencia al uso del ensayo de azul de metileno para evaluar  las  características  de  las  partículas  finas contaminantes o nocivas en un suelo;  los diferentes procedimientos consisten, básicamente, en medir  la capacidad de adsorción de azul de metileno por una muestra  de  suelo,  capacidad  representada  como  la cantidad  de  colorante  requerido  para  recubrir  las superficies específicas de las moléculas de los finos. En nuestro país su aplicación se ha limitado a ser un dentro  de  las  especificaciones  INVIAS  y  como exigencia en las normas IDU.

  8. SECAGEM INTERMITENTE E SEUS EFEITOS NA QUALIDADE FISIOLÓGICA DE SEMENTES DE TREMOÇO AZUL

    D.C. AHRENS

    1996-05-01

    Full Text Available Dois modelos de secadores comerciais, um intermitente lento, com a temperatura do ar de secagem a 60oC e a 65oC e outro rápido a 50oC, foram testados para a avaliaç��o da redução do grau de umidade de 20 para 13% e sua influência na qualidade fisiológica das sementes de tremoço azul (Lupinus angustifolius L.. Foram realizados testes de germinação, envelhecimento artificial e emergência em campo, após a secagem, aos três e seis meses de armazenamento. Os testes de germinação e envelhecimento artificial não detectaram diferenças significativas entre a qualidade das sementes secadas nos secadores e das secadas à sombra. Na semeadura aos seis meses, as emergências em campo foram 81%, 89%, 90% e 83% para os secadores intermitente lento a 60oC, a 65oC, para o intermitente rápido a 50oC e para a secagem à sombra, respectivamente. O secador intermitente rápido, onde as sementes passam rapidamente pela câmara de secagem e permanecem maior período na equalização, reduziu em média 1,1 pontos porcentuais por hora o teor de água das sementes e na secagem intermitente lenta a 65oC e a 60oC obteve-se 2,3 e 2,7 pontos porcentuais por hora, portanto mais eficientes que o primeiro, quando comparadas umidades iniciais/finais semelhantes. Conclui-se que o secador intermitente lento apresenta a velocidade de secagem superior ao rápido e que a qualidade fisiológica das sementes de tremoço não é afetada pela secagem nos diferentes secadores.Two commercial intermittent dryers, one slow (60oC and 65oC air temperature and another rapid (50oC, were tested to evaluate the water content decrease (20% to 13% and their influence on the physiological quality of Lupinus angustifolius L. seeds. The seeds were evaluated through physiological analysis (germination, accelerated ageing and field emergence, stored for 3 and 6 months. After six months the field emergence results were 81%, 89%, 90% and 83% for the slow 60oC, 65oC, rapid (50o

  9. Utilização de resíduos de materiais cerâmicos na adsorção de corante azul de metileno

    L. Dominguini

    2014-06-01

    Full Text Available Este trabalho estuda a viabilidade de utilização de resíduos de materiais cerâmicos como agentes de adsorção de corantes utilizados em indústrias têxteis. Resíduos de materiais cerâmicos, oriundos de quebras de tijolos, azulejos e pisos foram selecionados, triturados e moídos a uma granulometria adequada, o que possibilitou o estudo da influência do tipo de material cerâmico (resíduo e da sua granulometria sobre a adsorção do corante azul de metileno. Os resíduos cerâmicos foram separados em três diferentes granulometrias, fina (0,15 mm < Dfino< 0,30 mm, média (0,30 mm < Dmédio< 1,18 mm e grossa (1,18 mm azul de metileno presente na amostra ensaiada. No entanto, os resultados também mostram que a absorção de água do material cerâmico pode não ser somente o fator que influencia na adsorção do corante.

  10. Combustión espontánea de las harinas de pescado azul: Factores de influencia y peligrosidad en el transporte

    San José, M. J.

    1995-02-01

    Full Text Available Fish meal production characteristics and treatment are described, together with a detailed explanation of the international regulations for its maritime transport, as well as of the requirements for its stabilization to avoid its spontaneous combustion. Experience with this kind of transport, as well as Intensive research carried out over several years, has shown that the high fat content in several kinds of fish and the environmental humidity and temperature have a great influence and transform this kind of cargo into dangerous goods. Knowledge of proper stowage and cargo distribution in the holds greatly decreases the dangers during maritime transport. Good transport practice and stabilization of the meal with antioxidants together with the conclusions reached after research, make maritime transport of these cargoes safer.

    Se detallan las características de la fabricación y tratamiento de la harina de pescado azul, junto con un amplio desarrollo de las disposiciones internacionales para su transporte por vía marítima, así como la necesidad de estabilizar la harina de pescado para evitar la combustión espontánea. La experiencia en este transporte, además de las investigaciones realizadas durante varios años, ha puesto de manifiesto que el contenido de grasa en el pescado azul, la humedad y la temperatura, tienen una gran influencia y convierten a estos cargamentos en mercancías peligrosas. El conocimiento de una buena estiba o distribución de la carga dentro de las bodegas reduce considerablemente la peligrosidad en su transporte por mar. Esta práctica en el transporte y su estabilización con antioxidantes, junto con las conclusiones aportadas en la investigación, determinan un viaje más seguro en el transporte de estas mercancías.

  11. Visibilidad y enunciabilidad en la larga duración de la violencia política: La sombra azul de Sergio Schmucler

    Graciana Vásquez Villanueva

    2015-06-01

    Full Text Available Una historia de vida, eje fundamental de un film, es la discursividad que hemos indagado para percibir sentidos nuevos en la relación cine, memoria y violencia en la zona amplia de los discursos producidos sobre el terrorismo de estado en Argentina. La sombra azul, con guión y dirección de Sergio Schmucler, irrumpe para desbaratar conciencias. Nuestro trabajo, filiado en el Análisis del Discurso, se ha detenido en la indagación de tres dispositivos: las visibilidades, las enunciabilidades y las temporalidades, superpuestas, fragmentarias a veces, otras omnipresentes, deslizadas en la larga duración de una memoria social. Estos dispositivos, elaborados por Foucault para blandir discursividades exasperantes de órdenes impuestos, constituyen un camino privilegiado para llegar, a través de su desgranamiento, a una verdad intolerable forjada en este film. En La sombra azul la larga duración de la violencia de estado, la impunidad de los represores durante la democracia y, fundamentalmente, un sobreviviente —a la tortura, la prisión, el exilio, perteneciente a la fuerza policial de una de las provincias más castigadas por la dictadura— son cincelados, en la heteroglosia, en el diálogo y en el antagonismo, con otras voces. Este sobreviviente, devenido en re-viviente señala cómo un marco ético, capaz de valorar la tragedia humana, lo erige en un don para dotar de verdad, para esclarecer a una sociedad que, en muchos espacios, aún permanece en sombra. Este recorrido discursivo señala cómo, desde la indecibilidad original de un sujeto doliente, irrumpen visibilidades y enunciabilidades capaces de decir verdad y así proseguir con una memoria que nunca cesa.

  12. Análisis socioeconómico e interrelación de las pesquerías de sardina y atún aleta azul en la región noroeste de México

    Raúl Jesús del Moral-Simanek

    2010-01-01

    Full Text Available El establecimiento de las engordas de atún aleta azul en las costas de Baja California cambió el destino de las capturas de sardina, ya que antes se destinaban al mercado de congelados y a la elaboración de harina de pescado, y en la actualidad se utilizan como alimento para el atún aleta azul. Esto generó un efecto socioeconómico positivo para los armadores y pescadores de pelágicos menores, ya que la llegada de grandes capitales foráneos para el desarrollo de las engordas de atún mejoró los precios de la sardina, e hizo más rentable su pesquería.

  13. Feeding of blue marlin Makaira nigricans off Mazatlan, Sinaloa, Mexico Alimentación del marlin azul Makaira nigricans del área de Mazatlán, Sinaloa, México

    Leonardo Abitia-Cárdenas

    2010-01-01

    Full Text Available We analyzed the stomach contents of 52 blue marlins caught between October 2002 and October 2004 by the sport-fishing fleet of Mazatlan, Sinaloa, in the gulf of California, Mexico. Blue marlin feed on 15 food items. According to the index of relative importance (IRI, the most important prey were the frigate or bullet mackerel Auxis spp. (52% and jumbo squid Dosidicus gigas (30%.Se analiza el contenido estomacal de 52 marlines azules capturados por la flota de pesca deportiva que operó en el área de Mazatlan, Sinaloa, en el golfo de California, México, durante el periodo octubre 2002 a octubre 2004. El marlin azul se alimenta de 15 categorías alimenticias (ítemes, de las cuales las más importantes de acuerdo al índice de importancia relativa (IRI, fueron el pez melva Auxis spp. (52% y el calamar gigante Dosidicus gigas (30%.

  14. Alterações clínicas e patológicas em ovinos infectados naturalmente pelo vírus da língua azul no Rio Grande do Sul

    Nadia A.B. Antoniassi; Saulo P. Pavarini; Luiz A.O. Ribeiro; Mariana S. Silva; Eduardo F. Flores; David Driemeier

    2010-01-01

    Língua azul (LA) é uma doença causada pelo vírus da língua azul (VLA) e transmitida por vetores do gênero Culicoides. Estudos sorológicos têm demonstrado a ampla presença do vírus no Brasil; entretanto, informações clínicas da LA na América do Sul são limitadas. Esse trabalho descreve alterações clínico-patológicas em ovinos acometidos pela LA no Sul do Brasil. Em dois surtos, em propriedades distintas, 15 ovinos apresentaram como principais sinais clínicos hipertermia, apatia, aumento de vol...

  15. Estudo clínico-epidemiológico da doença de Chagas no distrito de Serra Azul, Mateus Leme, centro-oeste do Estado de Minas Gerais Clinic and epidemiological study on Chagas disease in the Serra Azul district of Mateus Leme, central-western region of the State of Minas Gerais, Brazil

    Élvio Marques da Silva

    2010-04-01

    Full Text Available INTRODUÇÃO: A doença de Chagas permanece como grave problema de saúde pública na América Latina, mesmo com o controle de sua transmissão. Esse estudo avaliou a prevalência da doença de Chagas no distrito de Serra Azul, Centro-Oeste de Minas Gerais, identificando as anormalidades eletrocardiografias dos indivíduos com sorologia positiva. MÉTODOS: A sorologia para doença de Chagas foi realizada em 676 indivíduos (48% da população. O exame clínico e o eletrocardiograma (ECG foram realizados na população sorologicamente positiva. Selecionou-se um grupo controle para comparação dos dados do ECG. RESULTADOS: A população estudada residia principalmente em área rural, com baixo nível sóciocultural. Quatorze indivíduos foram positivos, com prevalência de 2,1%. Os indivíduos chagásicos eram de faixa etária mais avançada (67 vs 39 anos; p INTRODUCTION: Chagas disease remains a severe public health problem in Latin America, despite control over its transmission. This study evaluated the prevalence of Chagas disease in the Serra Azul district, in the central-western region of the State of Minas Gerais, through identifying electrocardiographic (EKG abnormalities among serologically positive individuals. METHODS: Specific serological tests for Chagas disease were carried out on 676 individuals (48% of the population. Clinical examinations and EKGs were performed on the serologically positive population. A control group was selected for comparison with the EKG data. RESULTS: The study population lived mainly in rural areas, with low sociocultural level. Forty subjects were positive (prevalence of 2.1%. The individuals with Chagas disease were in an older age group (67 vs. 39 years; p < 0.001. EKG abnormalities were frequent among the individuals with Chagas disease (79%. Among the seropositive individuals, the EKGs showed greater prevalence of ventricular premature beats and conduction disorder of the right branch alone or in

  16. U-Pb zircon and 40Ar/39Ar geochronology of sericite from hydrothermal alteration zones: new constraints for the timing of Ediacaran gold mineralization in the Sukhaybarat area, western Afif terrane, Saudi Arabia

    Harbi, Hesham M.; Ali, Kamal A.; McNaughton, Neal J.; Andresen, Arild

    2018-04-01

    The Sukhaybarat East and Red Hill deposits, in the northeastern part of the Arabian Shield, are mesothermal vein-type gold deposits hosted by late Cryogenian-Ediacaran intrusive rocks of the Idah suites (diorite, tonalite, granodiorite) and, at Sukhaybarat East, also by Ediacaran metasedimentary rocks. Gold mineralization comprises quartz-arsenopyrite veins (Sukhaybarat East), quartz-carbonate-pyrite veins (Red Hill), and subordinate gold-base metal sulfide veins. In the Red Hill deposit, alteration is complicated due to multiple overprinting hydrothermal events and is characteristically affected by pervasive, pink quartz-K-feldspar-hematite alteration which is overprinted by potassic alteration characterized by a quartz-biotite-carbonate-muscovite/sericite-rutile-apatite assemblage. This assemblage is associated with molybdenite veins which appear to form late in the paragenetic sequence and may represent either evolution of the ore fluid composition, or a later, unrelated mineralized fluids. Hydrothermal alteration at the Sukhaybarat East deposit is dominated by quartz-carbonate-sericite-arsenopyrite assemblages. Zircon from ore-hosting tonalite at Sukhaybarat East yields a U-Pb age of 629 ± 6 Ma, and biotite from the same rock gives an 40Ar/39Ar age of 622 ± 23 Ma. The 40Ar/39Ar age is within the uncertainty range for the U-Pb age of the host intrusion and is interpreted as a minimally disturbed cooling age for the tonalite. In the Red Hill area, granodiorite was emplaced at 615 ± 5 Ma, whereas muscovite/sericite separated from a mineralized sample of a quartz-carbonate-pyrite vein, that was overprinted by molybdenite-bearing veinlets, yields an 40Ar/39Ar age of 597 ± 8 Ma. We interpreted this age to represent the maximum age of the molybdenite mineralization and the probable minimum age of gold mineralization in the Red Hill deposit.

  17. Perimetria azul-amarelo em usuários de tabaco-álcool Blue-on-yellow perimetry in tobacco and alcohol consumers

    José Fernando de Carvalho Júnior

    2006-10-01

    Full Text Available OBJETIVO: Avaliar as alterações de campo visual em usuários crônicos de tabaco e álcool por meio da perimetria azul-amarelo estratégia 10-2. MÉTODOS: Quarenta e dois olhos de vinte e um voluntários usuários de tabaco e álcool, todos do gênero masculino, foram selecionados após exame oftalmológico completo e normal, sendo submetidos a perimetria azul-amarelo estratégia 10-2. Quinze voluntários participaram do grupo controle. A análise dos dados foi realizada mediante gráfico da profundidade do defeito e número de pontos alterados. RESULTADOS: Observou-se que 40 olhos (95,3% dos usuários crônicos de tabaco e álcool, apresentaram maior freqüência de alterações no gráfico de profundidade do defeito (>10dB e 27 olhos (64,3% apresentaram número de pontos alterados (>10 pontos, (pPURPOSE: To evaluate the visual field changes in blue-on-yellow perimetry (B/Y strategy 10-2 in alcohol and tobacco smoking consumers. METHODS: Forty-two eyes of twenty-one users were studied. Fifteen individuals were used as a control group. All volunteers were males. After normal ophthalmologic examinations, central 10-2 (B/Y was performed in both eyes. Analysis of the results was performed through the alterations in the depth graph defect and number of altered points. RESULTS: It was found that the majority of the chronic alcohol and tobacco smoking consumers had a greater frequency of alterations in the depth graph defect; 40 eyes (95.3%, (>10dB, and 27 eyes (64.3% showed a number of altered points, (>10 points, (p<0.0001. All those who were used as a control group showed alterations in the depth graph defect and number of altered points, but had less than 10dB and 10 altered points, respectively. CONCLUSION: A higher number of abnormal points and depth graph defects and number of altered points were observed in alcohol and tobacco smoking consumers reflecting a higher number of alterations in the cells of the parvocellular system, responsible

  18. Los lípidos en la nutrición del abulón azul, molusco con potencial de cultivo

    Eduardo Durazo Beltrán

    2014-01-01

    Full Text Available Se evaluó el efecto del tipo y nivel de lípidos en el crecimiento y metabolismo de ácidos grasos en abulón azul. La primera parte del estudio se realizó en una granja comercial, donde se analizaron tres tratamientos de alimentación (alimento formulado, macroalga fresca y la combinación de ambos sobre parámetros biológicos y composición de ácidos grasos de organismos juveniles en un periodo de 329 días. Los perfiles de ácidos grasos de los abulones sugieren su capacidad para sintetizar ácidos grasos poliinsaturados n-3 y n-6 de cadena larga a partir de precursores de cadena más corta. En el segundo experimento se evaluó el efecto de la fuente y nivel de ácidos grasos, con trece tratamientos de alimentación y el uso de cuatro aceites comestibles, sobre el crecimiento y composición de ácidos grasos en tejido muscular. No se determinó una relación significativa entre crecimiento y un determinado tipo o nivel de ácido graso, pero se establecieron requerimientos de ácidos grasos n-3 y n-6.

  19. Activación mecánica del caolín como vía para la fabricación de azul ultramar

    Oscar Jaime Restrepo Baena

    2004-01-01

    Full Text Available La molienda del caolín en molinos de anillos causa una destrucción progresiva de la estructura cristalina original. Los estudios granulométricos demuestran que la molienda de los granos de caolín se produce por fuerzas de cizalladura, ocasionando un deslizamiento de los planos que conforman las partículas, distorsionándolas y aglomerándolas. El estudio de rayos X de mostró una pérdida casi completa de la estructura cristalina. Los análisis de DTA y TGA mostraron que la pérdida del agua de composición interna se produce desde el momento que comienza el calentamiento. Los estudios de microscopía electrónica de barrido muestran granos de forma y tamaño irregular que difieren notablemente de la muestra original. Con las muestras de caolín activado mecánicamente, se fabricó el pigmento Azul Ultramar utilizando un horno de tubo, los resultados obtenidos muestran un producto de características de calidad comparables a los conseguidos utilizando el caolín calcinado (10. Este estudio muestra que la activación mecánica del caolín, puede convertirse en una alternativa a la calcinación, proceso que actualmente se realiza a nivel industrial.

  20. AVALIAÇÃO DA TERAPIA FOTODINÂMICA COM AZUL DE METILENO EM Leishmania major e Leishmania braziliensis: ESTUDO in vitro

    Danielle El Atra Coelho

    2017-03-01

    Full Text Available A Leishmaníase é uma doença crônica causada pelo protozoário do gênero Leishmania, cujo tratamento é agressivo. A Terapia Fotodinâmica (TFD é uma alternativa promissora que combina luz, fotossensibilizador (FS e oxigênio molecular, para causar a morte celular. O objetivo desse trabalho foi avaliar, in vitro, a ação da TFD com Azul de metileno (AM em promastigotas de Leishmania, por teste de MTT, curva de crescimento e morfologia do parasito. O teste de MTT demonstrou alteração de ambas as espécies após interação com o AM no escuro e após TFD. A análise das curvas demonstrou que a TFD influenciou o crescimento das espécies. A análise morfológica revelou que o AM no escuro não causou alterações expressivas como a TFD, sendo a cepa de L. braziliensis mais afetada que a cepa de L. major. Pode-se concluir que a TFD com AM foi promissora contra promastigotas de Leishmania, pois foi capaz de diminuir o crescimento e alterar a morfologia dos parasitos em cultura.

  1. NUEVOS APORTES AL CONOCIMIENTO DE LA HERPETOFAUNA DE LA FORMACIÓN CERRO AZUL (MIOCENO SUPERIOR, PROVINCIA DE LA PAMPA, ARGENTINA

    AGUSTÍN SCANFERLA

    2015-01-01

    Full Text Available RESUMENSe describen nuevos materiales fósiles de anfibios y reptiles hallados en sedimentos referidos a la Formación Cerro Azul (Mioceno Superior, procedentes de numerosas localidades de la provincia de La Pampa, Argentina. Los nuevos registros se basan en un resto craneano de anuro asignado al géneroCeratophrys, restos de caparazón de tortugas terrestres del géneroChelonoidis, vértebras asignables al lagarto de la familia TeiidaeTupinambis, y una vértebra troncal de serpiente comparable al género de colubroideos actualesPhilodryas. Tanto los registros terciarios previos de géneros actuales de anfibios y reptiles en América del Sur, como así también la asociación recuperada en el Mioceno Superior de La Pampa sugieren que la mayoría de los géneros que componen la herpetofauna Neotropical estaban presentes en el Mioceno, patrón similar al observado en otras regiones del mundo.

  2. Captura de atún aleta azul en Baja California, México: ¿pesquería regional o maquiladora marina?

    Raúl Jesús del Moral-Simanek

    2009-01-01

    Full Text Available El atún aleta azul, capturado por la flota mexicana en las costas de la península de Baja California, se destinaba al enlatado local, para ofrecer a los consumidores nacionales un producto barato y con valor nutritivo alto. Sin embargo, esto cambió en la última década con la llegada de inversionistas, sobre todo japoneses. Ahora el atún se captura, engorda y exporta a los mercados japonés y estadounidense, que pagan un precio elevado, para satisfacer su demanda de sashimi. Esto tiene repercusiones positivas en el orden social y económico en México y Japón; determinadas a partir del trabajo de campo directo e indirecto realizado en el marco de esta investigación. Además, se identificaron algunas similitudes entre el comportamiento de las empresas estudiadas y la industria maquiladora de exportación, lo que abrió un debate sobre el tema.

  3. Influências da Guerra Fria no discurso nacionalista argentino. O retrato dos conflictos internacionais no Semanário Nacionalista Azul y Blanco

    Maria Valeria Galvan

    2014-12-01

    Full Text Available As notícias sobre as guerras internacionais desencadeadas no marco da Guerra Fria têm sido utilizadas pela discursividade nacionalista em pós do seu programa político próprio, mais vinculado ao contexto local do que ao internacional.O semanário político dos anos cinqüenta e sessenta, Azul y Blanco, virou testemunha disso. Este, embora tenha-se concentrado principalmente na política nacional, deixou filtrar em suas páginas notícias internacionais que expunham as problemáticas mais importantes da Guerra Fria nesses anos, desde uma óptica nacionalista que ia mais longe das identidades nacionais para construir um “nós” geograficamente mais amplo. Assim, apesar da maior relevância da Revolução Cubana nas páginas da revista, a situação do bloco oriental europeu e a Guerra do Vietnã foram também importantes na secção internacional. Essas notícias eram escritas por correspondentes e editores argentinos e estrangeiros. Ambos argentinos e estrangeiros tiveram posicionamentos políticos e ideológicos que ficaram comprometidos com seus respectivos cenários locais. Assim, eles contribuíram especialmente para as transformações que atravessava o discurso nacionalista local. Nesse sentido, as redefinições ideológicas e políticas do nacionalismo argentino desses anhos nutriram-se também de aqueles olhares.

  4. Applying persistent scatterer interferometry for surface displacement mapping in the Azul open pit manganese mine (Amazon region) with TerraSAR-X StripMap data

    Athayde Pinto, Carolina de; Paradella, Waldir Renato; Mura, José Claudio; Gama, Fabio Furlan; Ribeiro dos Santos, Athos; Silva, Guilherme Gregório; Hartwig, Marcos Eduardo

    2015-01-01

    The Azul mining complex, located in the Carajás Mineral Province, Amazon region, encompasses the most important manganese mine in Brazil. Vale S.A. company operates three simultaneous open pit excavations (mines 1, 2, and 3) in the area, which are conducted on rock alteration products of low geomechanical quality related to sandstones, siltstones, and a lateritic cover. In order to monitor ground deformation, 33 TerraSAR-X (TSX-1) StripMap images covering the period of March 2012-April 2013 were used in the investigation. An advanced differential interferometric synthetic aperture radar (A-DInSAR) approach based on persistent scatterer interferometry (PSI) using an interferometric point target analysis algorithm was applied, and the results showed that most of the area was considered stable during the time span of the synthetic aperture radar acquisitions. However, persistent scatterers (PS) with high deformation rates were mapped over a waste pile, probably related to settlements, and also along the north flank of mine 1, indicative of cut slope movements toward the center of the pit. A spatial relationship of geological structures with PS was observed for this sector of the mine, given by PS showing deformation rates concentrated along a structural corridor with faults, fractures, and folds related to the Carajás fault system. Though only ground-based radar measurements for wall benches of mine 1 were available for a short time period of the TSX-1 coverage, the PS movement patterns showed concordance with geotechnical field measurements. The investigation emphasized the important role that satellite-based A-DInSAR can play for deformation monitoring and risk assessment in this kind of mining area.

  5. Diagnosis of the generation, harvesting and leached treatment of the Relleno Sanitario Rio Azul and proposal of technological alternatives for its improvement

    Rojas Gonzalez, Ileana

    2007-01-01

    An environmental diagnosis was conduced in the Relleno Sanitario Rio Azul to evaluate the state of the generation, the harvesting and the leached treatment system. Besides, the corrective measures for each case were determined. The physicochemical characterization of the leached generated has been established through the collection of historical analysis conduced and the implementation of an environmental monitoring plan. As a consequence of said characterization, it was concluded that the leached generated at present possesses the specific characteristics of backfills that are found in mature stage (methanogenic), to know: low relation DBO/DQO, slightly basic pH, low concentration of heavy metals and low biodegradability. Even so these liquids must be treated to fulfill the permissible maximum parameters that establish the Reglamento de Uso y Vertido de Aguas Residuales. A seasonal variation linked with the generation of leached was determined, by effects of infiltration, toward the mass of waste and the combination of pluvial water with leached, mainly due to the absence of adequate infrastructure and unfinished works. The amount of leached that was generated and that will be generated until year 2025 it was managed to consider by means of the modeling a hydric balance. The volume is significant and is due to adopt the respective sanitary measures to guarantee to long term the adapted treatment of the leached and the fulfillment of the effective legislation. A series of improvements are proposed to the leached treatment system that functions at present, as a consequence of the diagnosis carried out to achieve that the quality of the effluent treated comply with the parameters of poured established; such as: filtration of heavy particles, implementation of a physicochemical treatment and treatment of muds. (author) [es

  6. Caracterização químico-mineralógica e espectroscopia Mössbauer de água-marinha da região de Pedra Azul, nordeste de Minas Gerais.

    Viana, Rúbia Ribeiro; Evangelista, Hanna Jordt; Costa, Geraldo Magela da

    2001-01-01

    Águas-marinhas de três pegmatitos localizados nas imediações da cidade de Pedra Azul, Minas Gerais, foram caracterizadas em termos de propriedades físicas e composição química, incluindo espectroscopia Mõssbauer. Os corpos pegmatíticos têm forma lenticular, ra- ramente ultrapassam 5m de largura e apresentam um pronunciado zonamento mineralógico e textural. Ó último evento termal registrado nes- tes pegmatitos, conforme determinado pelo método K-Ar em moscovita, ocorreu no Neoproterozóico. Est...

  7. Feeding of blue marlin Makaira nigricans off Mazatlan, Sinaloa, Mexico Alimentación del marlin azul Makaira nigricans del área de Mazatlán, Sinaloa, México

    Leonardo Abitia-Cárdenas; Dana Arizmendi-Rodríguez; Napoleón Gudiño-González; Felipe Galván-Magaña

    2010-01-01

    We analyzed the stomach contents of 52 blue marlins caught between October 2002 and October 2004 by the sport-fishing fleet of Mazatlan, Sinaloa, in the gulf of California, Mexico. Blue marlin feed on 15 food items. According to the index of relative importance (IRI), the most important prey were the frigate or bullet mackerel Auxis spp. (52%) and jumbo squid Dosidicus gigas (30%).Se analiza el contenido estomacal de 52 marlines azules capturados por la flota de pesca deportiva que operó en e...

  8. Diseño Box-Behnken para la optimización de la adsorción del colorante azul ácido sobre residuos de flores

    Jaramillo, Ana Cristina; Echavarría, Ana María; Hormaza, Angelina

    2013-01-01

    En este artículo se determinaron las mejores condiciones para la remoción del colorante Azul Ácido 9 (AA9) a través de un diseño factorial completo 2³ y su posterior optimización mediante un diseño de superficie Box- Behnken utilizando tallos de flores (TF) como material adsorbente. Las variables evaluadas fueron dosis de adsorbente (D), concentración de colorante (C) y tiempo de contacto (t). El contenido del colorante se cuantificó por espectrometría UV-Vis. El modelo estadístico presentó u...

  9. Uso do azul de metileno no tratamento de choque anafilático durante anestesia: relato de caso Uso del azul de metileno en el tratamiento de choque anafiláctico durante anestesia: relato de caso Methylene blue to treat anaphylaxis during anesthesia: case report

    Renato Mestriner Stocche

    2004-12-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: No período peri-operatório, o risco de anafilaxia deve sempre ser considerado. A incidência de reações alérgicas em anestesia é controversa, variando entre 1/3000 a 1/20.000, com mortalidade entre 3% e 9 %. Neste caso, relata-se o uso do azul de metileno como coadjuvante ao tratamento do choque anafilático refratário à terapêutica tradicional. RELATO DO CASO: Paciente do sexo masculino, 53 anos, submetido a herniorrafia inguinal sob raquianestesia. No final do procedimento, ao receber dipirona (1,5 g, por via venosa, o paciente imediatamente apresentou broncoespasmo, cianose, diminuição da SpO2 e da PAS, culminando com parada cardiorrespiratória. Foi iniciada reanimação cardiorrespiratória com massagem cardíaca externa, seguida de IOT e injeção de adrenalina (1 mg, atropina (1 mg, restabelecendo-se FC de 150 bpm, porém sem pulso palpável. Administrou-se mais 1 mg de adrenalina além de 1 g de hidrocortisona, com restabelecimento de pulso central (8 minutos. Apesar de receber dopamina (20 µg.kg-1.min-1, o paciente manteve-se hipotenso (60 mmHg até 80 minutos. Administraram-se 100 mg de azul de metileno por via venosa, quando houve aumento da PAS para 85 e 105 mmHg, após a segunda dose. Seguiu-se da diminuição da dose de dopamina de 20 para 10, 7, 5 e, finalmente, 2 µg.kg-1.min-1. CONCLUSÕES: A anafilaxia tem como principal mediador a liberação de histamina, que induz a produção de óxido nítrico (NO, com conseqüente aumento da guanilato ciclase que promove vasodilatação arteriolar por aumento do GMP cíclico. O azul de metileno pode ser útil nestas situações, pois inibe a guanilato ciclase e conseqüentemente a vasodilatação, o que resulta em melhora hemodinâmica.JUSTIFICATIVA Y OBJETIVOS: En el período peri-operatorio, el riesgo de anafilaxis siempre debe ser considerado. La incidencia de reacciones alérgicas en anestesia es polémica, variando entre 1/3000 a 1/20.000, con

  10. Geochemical, isotopic, and zircon (U-Pb, O, Hf isotopes) evidence for the magmatic sources of the volcano-plutonic Ollo de Sapo Formation, Central Iberia

    Montero, P.; Talavera, C.; Bea, F.

    2017-07-01

    The Ollo de Sapo Formation comprises variably metamorphosed felsic peraluminous volcanic rocks and highlevel granites that crop out over some 600km from the Cantabrian coast to central Spain in the northern part of the Central Iberian Zone. The Ollo de Sapo magmatism is not obviously connected with any major tectonic or metamorphic event so its origin is controversial. Some authors, based on trace-elements, have proposed that the Ollo de Sapo magmas originated in a supra-subduction setting but others, based on abnormally high zircon inheritance and field and structural data, favored a rifting environment. Here we present new oxygen and hafnium isotope data from the very characteristic Ollo the Sapo zircons, which in most cases, consist of ca. 485Ma rims and ca. 590-615Ma cores. We found that the Cambrian-Ordovician rims yielded unimodal distributions that cluster around ∂18O = 10, typical of S-type magmas formed from melting of altered crust. The Ediacaran cores, in contrast, cluster around ∂18O = 6.5, consistent with being arc-magmas. Rims and cores have the same average Hf isotope composition, but the rims are considerably more uniform. These data, coupled with existing wholerock element and Sr and Nd isotopic data, indicate that the Ollo de Sapo were S-type magmas that resulted from anatexis of younger-than-600Ma immature sediments mostly derived from different Ediacaran igneous rocks with a wide range of Hf isotope composition.

  11. Geochemical, isotopic, and zircon (U-Pb, O, Hf isotopes) evidence for the magmatic sources of the volcano-plutonic Ollo de Sapo Formation, Central Iberia

    Montero, P.; Talavera, C.; Bea, F.

    2017-01-01

    The Ollo de Sapo Formation comprises variably metamorphosed felsic peraluminous volcanic rocks and highlevel granites that crop out over some 600km from the Cantabrian coast to central Spain in the northern part of the Central Iberian Zone. The Ollo de Sapo magmatism is not obviously connected with any major tectonic or metamorphic event so its origin is controversial. Some authors, based on trace-elements, have proposed that the Ollo de Sapo magmas originated in a supra-subduction setting but others, based on abnormally high zircon inheritance and field and structural data, favored a rifting environment. Here we present new oxygen and hafnium isotope data from the very characteristic Ollo the Sapo zircons, which in most cases, consist of ca. 485Ma rims and ca. 590-615Ma cores. We found that the Cambrian-Ordovician rims yielded unimodal distributions that cluster around ∂18O = 10, typical of S-type magmas formed from melting of altered crust. The Ediacaran cores, in contrast, cluster around ∂18O = 6.5, consistent with being arc-magmas. Rims and cores have the same average Hf isotope composition, but the rims are considerably more uniform. These data, coupled with existing wholerock element and Sr and Nd isotopic data, indicate that the Ollo de Sapo were S-type magmas that resulted from anatexis of younger-than-600Ma immature sediments mostly derived from different Ediacaran igneous rocks with a wide range of Hf isotope composition.

  12. On the Sources of Salinity in Groundwater under Plain Areas. Insights from {delta}{sup 18}O, {delta}{sup 2}H and Hydrochemistry in the Azul River Basin, Argentina

    Zabala, M. E.; Varni, M.; Weinzettel, P. [Instituto de Hidrologia de llanuras, Azul (Argentina); Manzano, M. [Technical University of Cartagena (Spain)

    2013-07-15

    The Azul River basin, with some 6200 km{sup 2}, is located in the plains of Buenos Aires Province, Argentina. The Azul River flows along 160 km from the Tandilia Range, in the SW, to the Channel 11, in the NE. Average annual precipitation is 1005 mm (1988-2000); mean reference evapotranspiration is 1090 mm. The geology consists of Miocene to recent sediments, mostly sands and silts with some clay and calcrete layers, overlying crystalline rocks and marine sediments. The water table is shallow and groundwater in the aquifer upper 30 m displays an increasing salinity from SW to NE. The previous hypothesis to explain the salinity was infiltration of evapo-concentrated surface water, as the small soil slope in the northern basin (< 0.2%) induces rainfall accumulation in lowlands, where water evaporates prior to infiltration. But recent chemical and isotopic data reveal two salinity sources: evaporation of recent recharge water, and mixing with old saline groundwater of yet unknown origin. (author)

  13. APLICACIÓN DE LOS SIG PARA LA EVALUACIÓN DEL ESTADO DE CONSERVACIÓN DEL HÁBITAT DEL PAUJIL DE PICO AZUL CRAX ALBERTI (AVES: CRACIDAE EN EL NORORIENTE DE ANTIOQUIA, COLOMBIA

    Adriana María Molina

    Full Text Available El paujil de pico azul, Crax alberti, es un ave endémica del norte de Colombia en peligro crítico de extinción, sometida a la pérdida del hábitat y a la cacería de subsistencia como principales amenazas. Se desarrolló una aplicación de Sistemas de Información Geográfica (SIG para comparar el estado de conservación de las áreas de bosque, hábitat del paujil de pico azul, en 15 municipios de la región del nororiente de Antioquia en dos períodos de tiempo diferentes (1986 y 2002. La aplicación desarrollada que incorpora información cartográfica digital permitió clasificar ocho zonas definidas en el área de estudio para realizar un análisis de las prioridades de conservación. Se formularon, además, algunas recomendaciones para futuras aplicaciones de SIG como herramienta para la gestión de la conservación de especies amenazadas en Colombia.

  14. How Pore-Fluid Pressure due to Heavy Rainfall Influences Volcanic Eruptions, Example of 1998 and 2008 Eruptions of Cerro Azul (Galapagos)

    Albino, F.; Amelung, F.; Gregg, P. M.

    2016-12-01

    About 30 worldwide seismic studies have shown a strong correlation between rainfall and earthquakes in the past 22 years (e.g. Costain and Bollinger, 2010). Such correlation has been explained by the phenomenon of hydro-seismicity via pore pressure diffusion: an increase of pore-fluid in the upper crust reduces the normal stress on faults, which can trigger shear failure. Although this pore pressure effect is widely known for earthquakes, this phenomenon and more broadly poro-elasticity process are not widely studied on volcanoes. However, we know from our previous works that tensile failures that open to propagate magma through the surface are also pore pressure dependent. We have demonstrated that an increase of pore pressure largely reduces the overpressure required to rupture the magma reservoir. We have shown that the pore pressure has more influence on reservoir stability than other parameters such as the reservoir depth or the edifice loading. Here, we investigate how small pore-fluid changes due to hydrothermal or aquifer refill during heavy rainfall may perturb the conditions of failure around magma reservoirs and, what is more, if these perturbations are enough to trigger magma intrusions. We quantify the pore pressure effect on magmatic system by combining 1) 1D pore pressure diffusion model to quantify how pore pressure changes from surface to depth after heavy rainfall events and 2) 2D poro-elastic numerical model to provide the evolution of failure conditions of the reservoir as a consequence of these pore pressure changes. Sensitivity analysis is also performed to characterize the influence on our results of the poro-elastic parameters (hydraulic diffusivity, permeability and porosity) and the geometry of the magma reservoir and the aquifer (depth, size, shape). Finally, we apply our methodology to Cerro Azul volcano (Galapagos) where both last eruptions (1998 and 2008) occurred just after heavy rainfall events, without any pre-eruptive inflation. In

  15. Inibição da guanilato ciclase pelo azul de metileno no choque circulatório causado por pancreatite aguda necrosante: uma palavra de cuidado embasada em modelo suíno

    Caroline Floreoto Baldo

    Full Text Available OBJETIVO: estudar o uso terapêutico do bloqueio da guanilato ciclase pelo azul de metileno em um modelo experimental de pancreatite aguda grave em suínos. MÉTODOS: a pancreatite aguda necrotizante foi induzida em porcos anestesiados por infusão ductal pancreática retrógrada de 1ml/kg de taurocolato de sódio a 5% e 8U/kg de enteroquinase. Três grupos foram estudados (n=5: controle (C, pancreatite (PA, "bolus" de azul seguido por pancreatite (AM+PA. Os dados incluíram enzimas séricas e do líquido abdominal, variáveis hemodinâmicas, hemogasometria arterial, volume de líquido abdominal, marcadores inflamatórios plasmáticos, nitrito/nitrato e mieloperoxidase e malondialdeído plasmático. Aplicou-se a análise de variância seguida do pós-teste de Bonferroni (p<0,05. RESULTADOS: os valores de amilase e lipase foram três e dez vezes mais elevados no grupo PA. A atividade da mieloperoxidase foi 50% superior no grupo PA. Os dados hemodinâmicos indicaram choque hipovolêmico precoce seguido de choque cardiogênico. Observou-se grave translocação de líquidos para a cavidade peritoneal. A nitrito/nitrato plasmática permaneceu inalterada. O grupo AM+PA teve aumento de cinco vezes do mieloperoxidase em comparação com o grupo C. CONCLUSÕES: a utilização de azul de metileno em suínos com pancreatite não demonstrou efeitos significativos sobre variáveis hemodinâmicas e inflamatórias. Seu uso terapêutico na pancreatite necro-hemorrágica pode ser inadequado e extremo cuidado deve ser tomado dado o aumento da peroxidação lipídica evidenciado pelo aumento dos valores do malondialdeído.

  16. La Verbena azul en el tratamiento del niño con salpullido The blue Verbena to treat the child with rash

    Roberto Galiano Piquet

    2012-03-01

    Full Text Available Introducción: la miliaria es una enfermedad inflamatoria de la piel, usualmente conocida como salpullido, es muy frecuente en niños pequeños sobre todo en los meses de verano. Objetivo: valorar la eficacia de la infusión de Verbena azul en el control de la miliaria común. Métodos: se realizó un ensayo clínico fase II, a partir de la preparación de una infusión de hojas frescas o secas molidas, que se vertieron en 12 litros de agua hirviente, se tapó y se separó del fuego después de añadirle la planta, se dejó reposar y se coló. Fue aplicada tibia en todo el cuerpo durante 21 días, en dos secciones, al levantarse, y en la tarde luego del baño diario. El estudio se realizó en 30 lactantes de raza blanca, que acudieron con esta patología a la consulta de Medicina Natural y Tradicional, en el consultorio 6 del poblado de Altagracia, en el periodo entre junio del 2004 y junio del 2005, los cuales pertenecían al Policlínico Comunitario Docente "Carlos J. Finlay" de la Ciudad de Camagüey. Los datos se recogieron mediante una encuesta, confeccionada de acuerdo con los objetivos planteados en la investigación. Resultados: el grupo más afectado fue el de 3 a 6 meses, todos los pacientes fueron blancos, no se encontraron diferencias significativas en cuanto al sexo. La variedad clínica más frecuente fue la cristalina, y los meses en que más se presentó fueron entre junio y agosto. Conclusiones: este tratamiento presentó una alta eficacia en el control de la sintomatología de la miliaria común; se curaron 9 de cada 10 pacientes.Introduction: miliaria is an skin inflammatory disease known as rash and is very frequent in small children mainly during summer months. Objective: assessing the efficacy of the infusion of blue Verbena in controlling common heat rash. Methods: a phase II clinical trial was conducted from the preparation of an infusion of fresh leaves or dry grinded poured out in 12 liters of boiling water, was covered

  17. Efeito do lipopolissacarídio bacteriano sobre o esvaziamento gástrico de ratos: avaliação do pré-tratamento com dexametasona e azul de metileno

    Collares Edgard Ferro

    2003-01-01

    Full Text Available RACIONAL: O óxido nítrico pode estar envolvido no retardo do esvaziamento gástrico produzido pelo lipopolissacarídio bacteriano. OBJETIVO: Avaliar o efeito do pré-tratamento com a dexametasona, bloqueadora da indução do óxido nítrico-sintetase induzida e com o azul de metileno, que bloqueia a guanilato-ciclase, inibe as óxido nítrico-sintetases e inativa o óxido nítrico, sobre o retardo do esvaziamento gástrico determinado pelo lipopolissacarídio em ratos. MATERIAL E MÉTODOS: Foram utilizados ratos Wistar, machos, ''specific patogen free'', após 24 horas de jejum alimentar. No pré-tratamento foram empregadas, via intravenosa, soluções de dexametasona (3 e 6 mg/kg, azul de metileno (2 mg/kg e veículo estéril. O tratamento constou da administração, via intravenosa, de lipopolissacarídio (50 mig/kg e veículo. O intervalo entre o pré-tratamento e o tratamento foi de 10 minutos, exceto no estudo com dexametasona 6 mg/kg, que foi de 1 hora. O intervalo entre a administração do lipopolissacarídio e a avaliação do esvaziamento gástrico foi de 1 hora, exceto nos dois estudos com dexametasona 3 mg/kg que foram de 2 e 8 horas. O esvaziamento gástrico foi avaliado, indiretamente, através da determinação da percentagem de retenção gástrica de solução salina marcada com fenol vermelho. RESULTADOS: Os valores de retenção gástrica, nos animais pré-tratados com dexametasona ou azul de metileno e tratados com veículo, não diferiram significativamente dos observados nos que receberam veículo nos dois momentos. Os animais pré-tratados com veículo e tratados com lipopolissacarídio apresentaram valores de retenção gástrica significativamente mais elevados que nos controles. O pré-tratamento com dexametasona não interferiu no aumento da retenção gástrica determinado pelo lipopolissacarídio, nas primeiras 2 horas após administração da endotoxina. Oito horas após a administração da endotoxina, foi

  18. Estudo da descoloração do corante FD&C azul no 2 Indigotina pelo tratamento combinado do fungo Trametes versicolor e processo de filtração lenta

    Lopes, Maria Margareth Gonçalves; Sales, Paulo de Tarso Ferreira; Campos, Luiza Cintra; Schimidt, Fernando; Santiago, Mariângela Fontes

    2014-01-01

    O uso de fungos na descoloração de corantes com métodos economicamente viáveis de produção de água bacteriologicamente segura há muito vem sendo descrito por diversos autores. Este trabalho teve por objetivo investigar a eficiência da remoção de corante artificial FD&C azul no 2 Indigotina, com uso do fungo de degradação branca Trametes versicolor em combinação com a filtração lenta. Para a realização dos trabalhos, foram instalados dois protótipos de filtros lentos denominados FL-A e FL-B - ...

  19. Coloración de azul de metileno como alternativa para determinar la viabilidad de larvas libres de Trichinella spiralis Methylene blue test for the determination of viability of free larvae of Trichinella spiralis

    V.R. Randazzo

    2010-06-01

    Full Text Available El objetivo de la presente investigación fue determinar si la coloración con azul de metileno, de probada utilidad para demostrar la viabilidad de protoescólices de Echinococcus granulosus, puede evidenciar también la viabilidad de larvas libres de Trichinella spiralis. Para ello se utilizaron tres suspensiones de larvas de T. spiralis (M1, M2 y M3, las que fueron expuestas a diferentes condiciones y observadas a distintos tiempos: M1 se expuso a -30 °C y se observó a los 70 días; M2 a 80 °C durante 5 minutos y se observó inmediatamente, y M3 se mantuvo a 4 °C durante todo el experimento, como testigo del 100% de vitalidad. Cada suspensión contenía 500 estadios larvarios libres. Se emplearon 100 μl de solución de azul de metileno 1:10 000 en agua destilada, agregados a igual volumen de suspensión de larvas, y las muestras fueron observadas al microscopio óptico para evaluar la motilidad. Los resultados evidenciaron que cuando las larvas de T. spiralis estaban muertas (M1 y M2, el 100% se coloreaban totalmente de azul en su interior, y las estructuras internas, en relación con la capa quitinosa, aparecían retraídas y algunas fragmentadas. En la suspensión testigo M3 las larvas no se coloreaban, y como prueba adicional de viabilidad se pudo observar su típico movimiento en espiral en el 100% de ellas.The present research was carried out with the purpose of determining whether or not the methylene blue test could also evidence viability of free larvae of Trichinella spiralis, taking into account its usefulness in the determination of viability of protoscolices in Echinococcus granulosus. To this end, three T. spiralis larval suspensions (M1, M2 and M3 were used, each containing 500 free larval stages. A hundred μl of methylene blue solution 1:10000 in distilled water were added to 100 μl of the larval suspension. Larvae were observed under optical microscopy to evaluate motility. M1 was exposed to -30 °C and could be

  20. Effect of aspherical and yellow tinted intraocular lens on blue-on-yellow perimetry Efeito das lentes intraoculares asféricas e com pigmentação amarela na campimetria azul-amarelo

    Rodrigo França de Espíndola

    2012-10-01

    Full Text Available PURPOSE: To investigate the possible effect of aspherical or yellow tinted intraocular lens (IOL on contrast sensitivity and blue-on-yellow perimetry. METHODS: This prospective randomized bilateral double-masked clinical study included 52 patients with visually significant bilateral cataracts divided in two groups; 25 patients (50 eyes received aspherical intraocular lens in one eye and spherical intraocular lens in the fellow eye; and 27 patients (54 eyes received ultraviolet and blue light filter (yellow tinted IOL implantation in one eye and acrylic ultraviolet filter IOL in the fellow eye. The primary outcome measures were contrast sensitivity and blue-on-yellow perimetry values (mean deviation [MD] and pattern standard deviation [PSD] investigated two years after surgery. The results were compared intra-individually. RESULTS: There was a statistically significant between-group (aspherical and spherical intraocular lens difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. There were no between-group significant differences (yellow tinted and clear intraocular lens under photopic or mesopic conditions. There was no statistically significant difference between all intraocular lens in MD or PSD. CONCLUSION: Contrast sensitivity was better under mesopic conditions with aspherical intraocular lens. Blue-on-yellow perimetry did not appear to be affected by aspherical or yellow tinted intraocular lens. Further studies with a larger sample should be carried out to confirm or not that hypotheses.OBJETIVO: Investigar a possibilidade de efeitos na sensibilidade ao contraste e nos resultados da campimetria azul-amarelo com implante de uma lente intraocular (LIO asférica ou de pigmentação amarela. MÉTODOS: Trata-se de um estudo prospectivo, randomizado, duplo-mascarado, envolvendo 52 pacientes portadores de catarata senil bilateral, divididos em dois grupos; 25

  1. Petrogenesis and geodynamic implications of Ediacaran highly fractionated A-type granitoids in the north Arabian-Nubian Shield (Egypt): Constraints from whole-rock geochemistry and Sr-Nd isotopes

    Sami, Mabrouk; Ntaflos, Theodoros; Farahat, Esam S.; Mohamed, Haroun A.; Hauzenberger, Christoph; Ahmed, Awaad F.

    2018-04-01

    Mineral chemistry, whole-rock geochemical and Sr-Nd isotopic data are reported for the Abu-Diab granitoids in the northern Arabian-Nubian Shield (ANS) of Egypt, to investigate their petrogenesis and geodynamic significance. Gabal Abu-Diab constitute a multiphase pluton, consisting largely of two-mica granites (TMGs) enclosing microgranular enclaves and intruded by garnet bearing muscovite granites (GMGs) and muscovite granites (MGs). The granitoids are weakly peraluminous (A/CNK = 1.01-1.12) and show high SiO2 (>72.9 wt%) and alkali (K2O + Na2O = 8.60-9.13) contents. The geochemical features show that they are post-collisional and highly fractionated A-type granitoids. Compared to their host TMGs, the microgranular enclaves are strongly peraluminous (A/CNK = 1.18-1.24) with lower SiO2 and higher abundances of trace elements. The TMGs are depleted in Ba, Nb, P and Ti and are enriched in LREEs relative to HREEs with weakly negative Eu anomalies (Eu/Eu* = 0.45-0.64). In contrast, the GMGs and MGs are extremely depleted in Ba, Sr and Ti and have tetrad-type REE patterns (TE1-3 = 1.1-1.3) with strongly pronounced negative Eu anomalies (Eu/Eu* = 0.03-0.26), similar to rare metals bearing granites. The Ediacaran (585 ± 24 Ma) TMGs, are characterized by restricted and relatively low initial 87Sr/86Sr ratios (0.70337-0.70382) that suggests their derivation from a depleted mantle source, with little contamination from the older continental crust. In contrast, the GMGs and MGs have extremely high 87Rb/86Sr and 87Sr/86Sr ratios that reflect the disturbance of the Rb-Sr isotopic system and may give an indication for magmatic-fluid interaction. However, all the granitoids display positive εNd(t) (4.41-6.57) and depleted mantle model ages TDM2 between 777 and 956 Ma, which indicate their derivation from a Neoproterozoic juvenile magma sources and preclude the occurrence of pre-Neoproterozoic crustal rocks in the ANS. The microgranular enclaves represent globules of hot mafic

  2. Heterologous expression of Fusarium oxysporum tomatinase in Saccharomyces cerevisiae increases its resistance to saponins and improves ethanol production during the fermentation of Agave tequilana Weber var. azul and Agave salmiana must.

    Cira, Luis Alberto; González, Gloria Angélica; Torres, Juan Carlos; Pelayo, Carlos; Gutiérrez, Melesio; Ramírez, Jesús

    2008-03-01

    This paper describes the effect of the heterologous expression of tomatinase from Fusarium oxysporum f. sp lycopersici in Saccharomyces cerevisiae. The gene FoTom1 under the control of the S. cerevisiae phosphoglycerate kinase (PGK1) promoter was cloned into pYES2. S. cerevisiae strain Y45 was transformed with this vector and URA3 transformant strains were selected for resistance to alpha-tomatine. Two transformants were randomly selected for further study (designated Y45-1 and Y45-2). Control strain Y45 was inhibited at 50 muM alpha-tomatine, in contrast, transformants Y45-1 and Y45-2 did not show inhibition at 200 muM. Tomatinase activity was detected by HPLC monitoring tomatine disappearance and tomatidine appearance in the supernatants of culture medium. Maximum tomatinase activity was observed in the transformants after 6 h, remaining constant during the following 24 h. No tomatinase activity was detected in the parental strain. Moreover, the transformants were able to grow and produce ethanol in a mix of Agave tequilana Weber var. azul and Agave salmiana must, contrary to the Y45 strain which was unable to grow and ferment under these conditions.

  3. Variation of monthly inventories of {sup 7}Be fallout in the soils of the sub-basins 3 and 4 in Mato Frio river, a tributary of Serra Azul river

    Esquivel, Alexander D., E-mail: alexander.esquivel@utp.ac.pa [Centro de Investigaciones Hidráulicas e Hidrotécnicas (CIHH / UTP – PA), Universidad Tecnológica de Panamá (Panama); Moreira, Rubens M., E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    In this study 72 soil samples collected right at the surface were analyzed. They were collected at two work parcels located within the basin of the Mato Frio Creek (total drainage area = 10.6 km²) located in the municipality of Itauna, except for a small fraction in its northern part, which is located in the municipality of Serra Azul. Both municipalities are in the State of Minas Gerais, Brazil. The sampling period covers the time span from May 2014 to May 2015, with the purpose of observing on a monthly basis the variation in the activity of the radionuclide Beryllium-7 ({sup 7}Be, Eγ = 477.6 keV) along a one year hydrologic cycle, stressing the dry and rainy seasons. The objective of this investigation was to establish a baseline for the alteration pattern of the {sup 7}Be content in the soil in order to use these results for future estimates of rates of erosion or accreation in areas of interest within this basin. In order to measure the {sup 7}Be activity in the collected samples, a gamma spectrometer was used, composed of a hyperpure germanium detector with a relative efficiency of 50%. The results indicate a net trend towards a marked variation in the activity of {sup 7}Be in relative to the period of year within which the samples were collected, which in turn results in a reduction or increase in the values of the {sup 7}Be monthly inventory in the topsoil. (author)

  4. Estudio arqueométrico comparativo de muestras de pinturas con azul egipcio, procedentes de la tumba de Nefertari siglo XIII a.C. y del Balneum, termas romanas, siglos I a.C., I d.C.

    Criado Portal, A. J.

    2011-06-01

    Full Text Available In the present work have studied two samples with the same pigment, Egyptian Blue, but from different sources. The difference between them is caused by the functionality. In the case of Nefertari´s tomb is decorating interior rooms carved into rock in which they would not suffer any damage since it does not accessed to that place anymore. In the case of Balneum´s baths is decorating very warm and humid rooms, and should resist deterioration resulting from human activity during the use of these baths.

    En el trabajo presentado se han estudiado dos muestras de pinturas con el mismo pigmento, azul egipcio, de distinta procedencia. Las diferencias entre ellas vienen causadas por la funcionalidad. En el caso de la tumba de Nefertari se trata de decorar estancias interiores excavadas en roca en las que no sufrirían deterioro alguno, dado que no se accedería a ese lugar nunca más. En el caso del Balneum se trata de pinturas que decoran ambientes muy húmedos y cálidos y que, además, deben resistir el deterioro derivado de la actividad humana en dichas termas.

  5. Utilização de zeólitas sintetizadas a partir de cinza de carvão para remoção de azul de metileno em água

    Denise Alves Fungaro

    2009-01-01

    Full Text Available A adsorção de azul de metileno de solução aquosa foi realizada usando-se zeólitas de cinza de carvão como adsorventes de baixo custo. A amostra de cinza de carvão foi convertida em zeólitas por tratamento hidrotérmico usando parâmetros de síntese diferentes. Os materiais foram caracterizados por análise físico-química e estudos de DRX e MEV. As isotermas de adsorção ajustaram-se ao modelo de Freundlich. Os valores da capacidade de adsorção foram similares para os adsorventes. Estudos cinéticos indicaram que a adsorção seguiu o modelo de pseudo-segunda-ordem./////////// The adsorption of methylene blue from aqueous solution was carried out using zeolites synthesized from coal ash as low-cost adsorbents. The coal ash sample was converted to zeolites by hydrothermal treatment using different synthesis parameters. The materials were characterized by physical-chemical analysis, XRD and SEM studies. The adsorption isotherms can be fitted by Freundlich model. The values of the adsorption capacity of adsorbents were similar for adsorbents. Kinetic studies indicate that the adsorption follows pseudo-second-order kinetic model.

  6. NGC 5044-N50: Una etapa evolutiva intermedia entre galaxias compactas azules (BCD) y enanas elípticas (dE)

    Cellone, S. A.; Buzzoni, A.

    The possible connection between dwarf elliptical (dE), dwarf irregular (dI), and blue compact dwarf (BCD) galaxies, is a subject of sustained interest, with deep consequences on our underestanding of star formation and evolution of galaxies. We present here observational results (ESO - CASLEO) on the dwarf galaxy N50 in the NGC 5044 Group, which appears to be at an intermediate stage BCD-dE, after its last star-formation burst. We focused on this galaxy because of its strong departure from the relation between luminosity and surface brightness profile curvature, despite its integrated color [(B-V)0=0.76], normal for a dE. However, new observations under sub-arcsec seeing conditions (ESO 3.6 m Tel.) showed several knots surrounding the nucleus whose colors (g-r, g-i, Gunn system) indicate, through evolutionary population synthesis models, ages around ~5 × 109 years with slightly sub-solar metallicities. The spectroscopic data support this scenario; hence, while the main component of N50 is an old (~ 15 × 109 yr) population, there is evidence of recent star formation activity within ~400 pc of the nucleus. The incidence of these structures on the anomalous profile of N50 is discussed, as well as the particular evolutive stage of this galaxy within the dE-BCD relation.

  7. Stellar formation

    Reddish, V C

    1978-01-01

    Stellar Formation brings together knowledge about the formation of stars. In seeking to determine the conditions necessary for star formation, this book examines questions such as how, where, and why stars form, and at what rate and with what properties. This text also considers whether the formation of a star is an accident or an integral part of the physical properties of matter. This book consists of 13 chapters divided into two sections and begins with an overview of theories that explain star formation as well as the state of knowledge of star formation in comparison to stellar structure

  8. Galaxy formation

    Silk, J.; Di Cintio, A.; Dvorkin, I.

    2014-01-01

    Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

  9. Estudo experimental de linfonodo sentinela na mama da cadela com azul patente e Tecnécio Tc99m Experimental study of the sentinel lymph node in the dog breast using blue dye and technetium Tc99m

    Luiz Gonzaga Porto Pinheiro

    2003-12-01

    Full Text Available Pesquisa do Linfonodo Sentinela (LS tem se mostrado efetiva na avaliação axilar nas portadoras de neoplasia mamária. O LS negativo torna desnecessário o esvaziamento axilar. OBJETIVO: Identificar o LS da região subareolar da mama em cadelas utilizando corante azul patente (AP, Tecnécio Tc99m ou a associação de ambas as técnicas e compará-las quanto à sensibilidade na detecção do linfonodo sentinela. MÉTODOS: Foram estudadas dezessete cães fêmeas. Um total de 55 mamas foram analisadas. Utilizou-se AP (2,5%/0,5 ml e/ou Tc99m (1,0 mC/0,8ml para identificação do LS. A aplicação do Tc99m era realizada duas horas antes da realização do experimento. O AP era injetado na região subareolar da mama. Localizado o LS, realizava-se sua exérese. RESULTADOS: Dos 44 linfonodos em que se utilizou AP, pôde-se verificar que 40 estavam corados (90,90%. Dos 48 linfonodos em que se utilizou Tc99m, 47 linfonodos estavam radioativos (97,91% (p=0.18; k= - 0.067. Nas 37 mamas em que se associou AP ao Tc99m, apesar de 02 linfonodos não estarem corados, todos estavam radioativos (AP vs AP+Tc: p=0.12; k=0.083; Tc vs AP+Tc: p=1.0; k=0.018. CONCLUSÃO: O Tc99m e o corante azul patente, isolados ou associados, prestam-se à identificação do LS da mama do animal.The sentinel lymph node research (SLN has been effective in the evaluation of nodal status in patients with breast cancer. A negative SLN makes an axillary lymphadenectomy unnecessary. PURPOSE: To identify the SLN of the subareolar region in female dog breasts using blue dye (BD, Technetium (Tc99m or the association of both techniques and to compare their sensibility in the detection of the SLN. METHODS: Seventeen female dogs were studied. 55 breasts were analyzed. DB and/or Tc99m were used for the identification of SLN. Tc99m was introduced two hours before the experiment. BD was introduced some minutes before the procedure. Once the SLN was localized its dissection was performed. RESULTS

  10. Alterações anatômicas em algodoeiro infectado pelo vírus da doença azul Anatomical alterations in blue disease infected cotton plant

    Juliana K. Takimoto

    2009-01-01

    Full Text Available A doença azul do algodoeiro está associada a um vírus ainda pouco conhecido em suas características morfológicas e moleculares, tanto quanto a sua patologia e epidemiologia. O tipo de transmissão circulativa pelo afídeo vetor Aphis gossypii Glover, associado a recentes relatos de estudos moleculares, sustentam ser o agente etiológico uma espécie membro da família Luteoviridae. No presente trabalho, estudos anatômicos comparativos em plantas sadias e infectadas foram realizados com a finalidade de conhecer aspectos estruturais da interação vírus-espécie hospedeira, com potencial aplicação na área de diagnose e melhoramento genético. Os estudos anatômicos foram realizados em folhas de plantas infectadas, com área foliar reduzida, nervuras cloróticas e margem foliar voltada para baixo. O encurtamento dos entrenós, que resultam em um agrupamento de folhas, flores e frutos, e conseqüente redução da altura da planta, do número e tamanho dos frutos, são expressões fenotípicas da planta de algodão infectada, a qual serviu para o presente estudo. Nas plantas infectadas com o agente da doença azul havia maior acúmulo de calose e de cristais de oxalato de cálcio, cloroplastos íntegros distribuídos na região periférica das células do mesofilo e aparente alteração química no interior das células do parênquima paliçádico. Inclusões nos vasos do floema e, ocasionalmente no xilema, também foram observadas. O acúmulo de calose e a presença de inclusões no floema podem indicar uma relação ou preferência do vírus por esse tecido.Cotton blue disease is caused by a virus whose morphological and molecular characteristics is not well known and so demanding information its phytosanitary and epidemiological characteristics. Evidences of an aphid borne (Aphis gossypii Glover circulative (persistent type of transmission, associated with a recent molecular report, sustain for a virus species belonging to the

  11. El secreto del huevo azul, de Catalina González Vilar. Estudio narratológico. The secret of the blue egg, by Catalina González Vilar. Narratological study

    Miguel Sánchez-García

    2013-11-01

    Full Text Available This article discusses a narratological study of the literary work The secret of the blue egg, by the writer Catalina Gonzalez Vilar, that won El Barco de Vapor prize in 2012. It examines the different constitutive elements of the text (topic approach, prominent figures, syntactic structure, narrative technique… and his contribution to the development of the story with the purpose of discovering the aesthetic and literary values that contribute to the fable. It aims at demonstrating the proper use of them all as they shape a text rich in nuances, striking, suggestive. All these qualities of great importance both in creations aimed at adults as well as at children and young people because they enrich the final value of the work, and by extension, the cultural background of their readers.Este trabajo aborda el estudio narratológico de la obra El secreto del huevo azul, de la escritora Catalina González Vilar, que obtuvo el Premio El Barco de Vapor en el año 2012. Examina los diferentes elementos constitutivos del texto (el enfoque del tema, la caracterización de los personajes, la estructura sintáctica, el tratamiento del lenguaje, la técnica narrativa utilizada… y su aporte al desarrollo de la historia con la finalidad de descubrir los valores estéticos y literarios que aporta a la fábula. Pretende demostrar el adecuado uso de todos ellos dado que favorecen un texto rico en matices, llamativo, sugerente. Cualidades, todas ellas, de gran importancia tanto en creaciones destinadas al público adulto como al infantil y juvenil pues enriquece el valor final de la obra, y por extensión, el bagaje cultural de sus lectores.

  12. Estudo da descoloração do corante FD&C azul no 2 Indigotina pelo tratamento combinado do fungo Trametes versicolor e processo de filtração lenta

    Maria Margareth Gonçalves Lopes

    2014-06-01

    Full Text Available O uso de fungos na descoloração de corantes com métodos economicamente viáveis de produção de água bacteriologicamente segura há muito vem sendo descrito por diversos autores. Este trabalho teve por objetivo investigar a eficiência da remoção de corante artificial FD&C azul no 2 Indigotina, com uso do fungo de degradação branca Trametes versicolor em combinação com a filtração lenta. Para a realização dos trabalhos, foram instalados dois protótipos de filtros lentos denominados FL-A e FL-B - no sobrenadante do filtro FL-A foi inoculado o referido fungo, e o filtro FL-B foi utilizado como controle (sem inoculação do microrganismo. O melhor percentual de remoção do corante pelo fungo Trametes versicolor em combinação com a filtração lenta foi de 44,74% 24 horas após a atividade máxima registrada de lacase. Os resultados mostraram que a filtração lenta combinada com o tratamento com o fungo T. versicolor não apresenta grande potencial para remoção de cor em 21 dias de tratamento, visto que os produtos microbianos gerados interferem no processo de filtração, diminuindo a eficiência do processo físico. Entretanto, restringindo o tempo de tratamento a 24 horas após a atividade enzimática máxima, o tratamento combinado apresentou boa eficiência.

  13. Photocatalysis of methylene blue contaminated water using titania fiber doped with silicon; Fotocatalise de aguas contaminadas com azul de metileno utilizando fibras de titania dopadas com silicio

    Ugarteche, C.V.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (LACER/UFRGS), Porto Alegre, RS (Brazil). Lab. de Materiais Ceramicos

    2009-07-01

    In this work, titania fibers doped with silicon were synthesized by electro spinning methodology, using titanium propoxide, silicon tetra propoxide and a solution of polyvinylpyrrolidone as precursors. The non-tissue material obtained was characterized by X-ray diffraction to determine the phase and crystallite size, BET method to determine the surface and SEM to analyze the microstructure of the fibers. The photo catalytic activity of the fibers in comparison with the standard TiO{sub 2} Degussa P25 was evaluated using a 20ppm methylene blue solution. The composition containing 30% of silicon kept the anatase phase stable until the heat treatment temperature of 800 deg C. In the other compositions there was a formation of the rutile phase, which is less photoactive. The compositions containing silicon were photo catalytic efficient and some of them were more active that the standard P25. (author)

  14. The role of microbial iron reduction in the formation of Proterozoic molar tooth structures

    Hodgskiss, Malcolm S. W.; Kunzmann, Marcus; Poirier, André; Halverson, Galen P.

    2018-01-01

    Molar tooth structures are poorly understood early diagenetic, microspar-filled voids in clay-rich carbonate sediments. They are a common structure in sedimentary successions dating from 2600-720 Ma, but do not occur in rocks older or younger, with the exception of two isolated Ediacaran occurrences. Despite being locally volumetrically significant in carbonate rocks of this age, their formation and disappearance in the geological record remain enigmatic. Here we present iron isotope data, supported by carbon and oxygen isotopes, major and minor element concentrations, and total organic carbon and sulphur contents for 87 samples from units in ten different basins spanning ca. 1900-635 Ma. The iron isotope composition of molar tooth structures is almost always lighter (modal depletion of 2‰) than the carbonate or residue components in the host sediment. We interpret the isotopically light iron in molar tooth structures to have been produced by dissimilatory iron reduction utilising Fe-rich smectites and Fe-oxyhydroxides in the upper sediment column. The microbial conversion of smectite to illite results in a volume reduction of clay minerals (∼30%) while simultaneously increasing pore water alkalinity. When coupled with wave loading, this biogeochemical process is a viable mechanism to produce voids and subsequently precipitate carbonate minerals. The disappearance of molar tooth structures in the mid-Neoproterozoic is likely linked to a combination of a decrease in smectite abundance, a decline in the marine DIC reservoir, and an increase in the concentration of O2 in shallow seawater.

  15. Methylene blue adsorption in clay mineral dealt with organic cation; Sorcao de azul de metileno em argila esmectitica tratada com cation organico

    Silva, T.L. [Universidade Federal do Para (UFPA), Maraba, PA (Brazil). Faculdade de Engenharia de Materiais; Lemos, V.P., E-mail: tls1981@hotmail.com [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Centro de Geociencias

    2011-07-01

    The interaction among organic cations, as the methylene blue (AM) and benzyltrimethylammonium (BTMA), and clay minerals of the group of the smectite they result in the formation of applied materials in the adsorption of organic pollutant presents in waters, soils and you cultivate. In this work they were prepared the adsorbents (organic-clays) smectite - AM and smectite-BTMA. The precursory sample of smectite was collected in Rio Branco-Acre. We were also used an smectite sample collected in Sena Madureira (SM)-Acre already characterized in previous work and a sample of standard smectite Swy-2-Na-Montmorillonite (SWy-2) of Wymong - USA. The organic agents selected for this study they were: Blue of Methylene, denominated AM and Benzyltrimethylammonium, denominated BTMA. They were appraised the capacities adsorptive of the treated samples with BTMA being used AM as adsorbate. The results of these evaluations detected that ran total adsorption of AM (concentrations varying from 1 to 10 ppm) for the treated samples with BTMA. The organic cation, BTMA, interacting with the surfaces of the natural clay was more efficient in the adsorption of AM than the clay without the previous treatment with this salt. (author)

  16. BLUETONGUE VIRUS ANTIBODIES DETECTIONS IN SHEEP FROM ARAÇATUBA REGION –SAO PAULO, BRAZIL DETECÇÃO DE ANTICORPOS CONTRA O VÍRUS DA LÍNGUA AZUL EM OVINOS NA REGIÃO DE ARAÇATUBA – SÃO PAULO, BRASIL

    Adriana Hellmeister de Campos Nogueira

    2009-12-01

    Full Text Available

    Bluetongue (BT is an infectious, insect-born viral disease of ruminants. The causative agent of BT is bluetongue virus (BTV that belongs to the family Reoviridae genus Orbivirus. Insect vectors in the genus Culicoides transmit this virus. BT affects domestic and wild ruminants, however small ruminants are considered the most affected specie. The aim of the study was to detect antibodies against BTV in commercial sheep farms, of the Northeastern region of Sao Paulo State, Brazil. A total of 1002 sera samples collected from adult sheep (above 1 year-old, comprising a total of 31 farms, were screened for the presence of BTV antibodies, by agar gel immunodiffusion test (AGID and ELISA-CFS (Enzyme Linked Immunosorbent Assay – competitive solid phase, both produced by Pan American Center of FMDV. From a total of 1002 samples, 651 (65% were positive by AGID and 742 (74.1%, were positive by ELISA-CFS. These results suggest that the BTV is widespread among farms, probably causing subclinical infections.

    KEY WORDS: AGID, bluetongue virus, ELISA-CFS, seroepidemiological survey.

    A língua azul é uma doença viral, cujo agente etiológico pertence à família Reoviridae, gênero Orbivirus, transmitida por um vetor (artrópode hematófago, do gênero Culicoides. Os animais acometidos são ruminantes domésticos e selvagens, porém os pequenos ruminantes são os mais afetados. O estudo teve como objetivo detectar a presença de anticorpos para língua azul em ovinos da região de Araçatuba, por possuir um rebanho expressivo e condições climáticas favoráveis à multiplicação de insetos. Foram analisadas 1.002 amostras de soros ovinos, provenientes de 31 cabanhas, pelas provas de imunodifusão dupla em gel de ágar (AGID e ELISA (Enzyme Linked immunosorbent Assay de competição da fase sólida (ELISA CFS, provenientes do Centro Panamericano de Febre Aftosa. Desses soros, 651 (65% foram

  17. Formative (measurement)

    Fassott, G.; Henseler, Jörg; Cooper, C.; Lee, N.; Farrell, A.

    2015-01-01

    When using measurement models with multiple indicators, researchers need to decide about the epistemic relationship between the latent variable and its indicators. In this article, we describe the nature, the estimation, the characteristics, and the validity assessment of formative measurement

  18. Cement Formation

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid......−liquid reactions are discussed, as are the influences of particles sizes on clinker phase formation. Furthermore, a mechanism for clinker phase formation in an industrial rotary kiln reactor is outlined....

  19. Star formation

    Woodward, P.R.

    1978-01-01

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  20. Galaxy Formation

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... is important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function...

  1. Uso do azul de metileno na reversão de vasoplegia refratária ao uso de catecolaminas após bypass aortobifemoral Use of methylene blue in the reversal of vasoplegia refractory to the use of catecholamines after aortobifemoral bypass

    Mariana Raphaela Garcia de Araújo dos Santos

    2010-01-01

    Full Text Available Há evidências de que o óxido nítrico (NO tem importância na vasodilatação associada a reações vasoplégicas. O objetivo deste relato de caso é documentar um caso de vasoplegia refratária ao uso de catecolaminas após bypass aortobifemoral revertida com o uso de azul de metileno. Mulher, 50 anos, submetida a bypass aortobifemoral. Sem comorbidades. Saiu de sala cirúrgica extubada, estável e com pulsos distais presentes. Duas horas após a cirurgia, evoluiu com choque circulatório. Iniciada noradrenalina e investigadas causas de choque. Manteve-se com necessidades crescentes de aminas e parâmetros estáveis. No sexto dia pós-operatório, com a hipótese de vasoplegia refratária, optou-se pelo uso do azul. Resposta imediata, com queda nos níveis de aminas, sendo desligada a noradrenalina no dia seguinte. O azul de metileno inibe a guanilato ciclase, produtora de guanosina monofosfato cíclico. Especula-se que haja um sinergismo entre essas drogas, já que a sua associação permite a atuação do sistema adenosina monofosfato.There is evidence that the nitric oxide plays an important role in the vasodilation associated with vasoplegic reactions. The objective of this case report is to document a case of catecholamine-refractory shock after aortobifemoral bypass treated with methylene blue. A 50-year-old woman was admitted for aortobifemoral bypass graft surgery. She did not present with any comorbidities. At the end of the surgery, she was breathing spontaneously, with palpable pedal pulses. Two hours later, the patient presented shock. Noradrenaline infusion was initiated and the causes of shock were investigated. She required increasing doses of amines and her parameters were stable. On the sixth day after surgery, methylene blue was administered due to the hypothesis of refractory vasoplegia. There was immediate response, with decrease in the catecholamine infusion levels until its withdrawal on the next day. Methylene blue

  2. Comet formation

    Blum, J.

    2014-07-01

    There has been vast progress in our understanding of planetesimal formation over the past decades, owing to a number of laboratory experiments as well as to refined models of dust and ice agglomeration in protoplanetary disks. Coagulation rapidly forms cm-sized ''pebbles'' by direct sticking in collisions at low velocities (Güttler et al. 2010; Zsom et al. 2010). For the further growth, two model approaches are currently being discussed: (1) Local concentration of pebbles in nebular instabilities until gravitational instability occurs (Johansen et al. 2007). (2) A competition between fragmentation and mass transfer in collisions among the dusty bodies, in which a few ''lucky winners'' make it to planetesimal sizes (Windmark et al. 2012a,b; Garaud et al. 2013). Predictions of the physical properties of the resulting bodies in both models allow a distinction of the two formation scenarios of planetesimals. In particular, the tensile strength (i.e, the inner cohesion) of the planetesimals differ widely between the two models (Skorov & Blum 2012; Blum et al. 2014). While model (1) predicts tensile strengths on the order of ˜ 1 Pa, model (2) results in rather compactified dusty bodies with tensile strengths in the kPa regime. If comets are km-sized survivors of the planetesimal-formation era, they should in principle hold the secret of their formation process. Water ice is the prime volatile responsible for the activity of comets. Thermophysical models of the heat and mass transport close to the comet-nucleus surface predict water-ice sublimation temperatures that relate to maximum sublimation pressures well below the kPa regime predicted for formation scenario (2). Model (1), however, is in agreement with the observed dust and gas activity of comets. Thus, a formation scenario for cometesimals involving gravitational instability is favored (Blum et al. 2014).

  3. Infección por el virus de la Lengua azul: activación de señales celulares que inducen apoptosis Bluetongue virus infection: signaling pathway activated during apoptosis

    E. Mortola

    2009-09-01

    Full Text Available El virus de la Lengua azul (VLA es un ARN virus de doble cadena que induce apoptosis tanto en cultivos celulares como en tejidos blanco. Con el fin de dilucidar el mecanismo de apoptosis en la infección por el VLA, en el presente trabajo examinamos en detalle, por la técnica de Western blot, las señales celulares de caspasas, Bax, citocromo c, Smac/DIABLO y factor nuclear kappa B (NF-kB que se activan en la infección viral. Hemos comprobado que luego de la infección in vitro con el VLA, se detectó la activación de la caspasa 8 y con ello el mecanismo extrínseco de la apoptosis. También detectamos por primera vez no sólo la activación de miembros de la familia Bcl-2 (Bax, sino también la liberación del citocromo c y la proteína Smac/DIABLO, confirmando que en la infección por el VLA está involucrado el mecanismo secuencial intrínseco de la apoptosis. Asimismo, demostramos que la infección por el VLA activa el NF-kB y que la apoptosis es sustancialmente reducida mediante la inhibición del mismo. La activación de las señales celulares tales como Bax, citocromo c, Smac/DIABLO y NF-kB presentados en este trabajo, esclarecen los mecanismos apoptóticos durante la infección por el VLA para una mayor comprensión del papel primario que juega la apoptosis en la patogénesis del virus.Bluetongue (BTV is a double-stranded RNA virus that induces apoptosis both in mammalian cell cultures and in target tissues. To elucidate the apoptosis pathways in BTV infection, we have examined in detail the apoptosis mechanism by examination of caspases, Bax, cytochrome c, Smac/DIABLO and NF-kB signalling pathways. In this report, after cell infection with BTV, the activation of caspase 8 was detected, proving the extrinsic receptor binding apoptotic pathway. Apoptosis followed a sequential pathway involving the detection of activated Bcl-2 family members. Furthermore, its translocation to the mitochondria, as well as the release of cytochrome c and

  4. Alterações de cromatina em espermatozóides de ovinos e caprinos avaliadas por azul de toluidina e alaranjado de acridina Chromatin alterations in ram and goat spermatozoa evaluated by toluidine blue and acridine orange

    Cristina de Figueiredo Kamimura

    2010-02-01

    Full Text Available Reprodutores com espermograma normal podem se comportar como subférteis ou passarem por períodos de subfertilidade. As alterações na cromatina dos espermatozóides são possíveis explicações encontradas para tais comportamentos. Conduziu-se este trabalho, com o objetivo de testar a eficiência de azul de toluidina (AT e do alaranjado de acridina (AA na identificação de alterações na compactação de cromatina em espermatozóides de ovinos e caprinos, além de avaliar a correlação entre essas alterações e as de morfologia espermática. Para tal, foram avaliadas amostras de sêmen de 15 ovinos e de 15 caprinos, com dez repetições para cada método por animal. Calcularam-se a média, o desvio padrão (DP e o coeficiente de variação (CV para cada técnica e animal. Utilizou-se o teste t-Student para avaliar diferença entre as médias obtidas nos dois métodos. Também foram calculados a correlação de Pearson e os coeficientes kappa ponderado e não ponderado para avaliar a concordância entre os métodos com AT e AA. Foi verificado que nem sempre as anomalias morfológicas de cabeça são acompanhadas por alterações na cromatina identificáveis pelos métodos utilizados neste trabalho. O método AT é mais estável e possui maior sensibilidade do que AA para ambas as espécies, sendo o mais indicado para caprinos. Contudo, em razão de apresentar repetibilidade muito baixa, ambos os métodos não são indicados para avaliação espermática em ovinos.Males with normal spermogram can behave as subfertile or pass for periods of subfertility. Chromatin alterations of spermatozoa can account for such behavior. The objective of the present work was to test the efficacy of toluidine blue (TB and acridine orange (AO in the identification of alterations in chromatin compaction in spermatozoa from rams and goats, in addition to evaluate the correlation between those alterations and the ones of spermatic morphology. In order to do that

  5. Biodegradation of remazol brilliant blue R by ligninolytic enzymatic complex produced by Pleurotus ostreatus Biodegradação do azul brilhante de remazol R pelo complexo enzimático ligninolítico produzido por Pleurotus ostreatus

    Kátia Maria Gomes Machado

    2006-12-01

    Full Text Available Pleurotus ostreatus ("shimeji" is produced in Brazil on a commercial scale using various lignocellulosic residues. Efforts have been made to reuse the culture residue to obtain products of greater aggregate value such as enzymes or in processes of bioremediation. We evaluated the Remazol brilliant blue R (RBBR degradation potential of extracts from solid substrate colonized by P. ostreatus and extracts from residue of the "shimeji" mushroom yield. Colonized substrates and residue were provided by Toyobo do Brasil Ltda. Extraction was performed with sodium acetate buffer (50 mM, pH 4.6. RBBR decolorization was monitored at 592 nm and peroxidase and laccase activities were measured by monitoring the oxidation of ABTS. Horseradish peroxidase was used as reference. The time of growth of P. ostreatus influenced RBBR degradation and peroxidase and laccase activities. Concentration of 1 mM H2O2 and pH 4.0 were the best for RBBR decolorization. Complete RBBR decolorization was obtained with the addition of only one aliquot of 50 µL of 1 mM H2O2. The stability of the extracts was higher when they were kept under refrigeration than when stored frozen. The potential application of the ligninolytic complex derived from P. ostreatus and mushroom residue for xenobiotic degradation was demonstrated.Pleurotus ostreatus ("shimeji" é produzido no Brasil em escala comercial empregando-se vários resíduos lignocelulósicos. Esforços têm sido feitos para reaproveitamento do resíduo do cultivo em produtos de maior valor agregado, como enzimas ou sua aplicação em processos de biorremediação. Foi feita avaliação do potencial de degradação do azul brilhante de remazol (RBBR por extratos obtidos de substratos sólidos colonizados por P. ostreatus e por extratos do resíduo da produção do cogumelo "shimeji". Substratos colonizados e o resíduo foram fornecidos pela Toyobo do Brasil Ltda. Extração foi feita com tampão acetato de sódio (50 mM, pH 4

  6. Zircon U-Pb geochronology, Sm-Nd and Pb-Pb isotope systematics of Ediacaran post-collisional high-silica Acampamento Velho volcanism at the Tupanci area, NW of the Sul-Rio-Grandense Shield, Brazil

    Sommer, Carlos Augusto; Leitzke, Felipe Padilha; Lima, Evandro Fernandes de; Barreto, Carla Joana Santos; Matté, Vinicius; Philipp, Ruy Paulo; Conceição, Rommulo Vieira, E-mail: casommer@sinos.net, E-mail: eflgeologo@gmail.com, E-mail: ruy.philipp@ufrgs.br, E-mail: rommulo.conceicao@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Geociências; Lafon, Jean Michel, E-mail: lafonjm@ufpa.br [Universidade Federal do Pará (UFPA), Belém, PA (Brazil). Laboratório de Geologia Isotópica; Basei, Miguel Ângelo Stipp, E-mail: baseimas@usp.br [Universidade de São Paulo (CPGeo/IGc/USP), São Paulo, SP (Brazil)

    2017-10-15

    We present new U-Pb zircon ages and Sm-Nd-Pb isotopic data for volcanic and hypabyssal acid rocks from the northernmost exposure of the Acampamento Velho Formation in the NW portion of the Sul-Rio-Grandense Shield, Brazil. The first volcanic episode, grouped in the high-Ti rhyolites from the Tupanci hill, shows age of 579 ± 5.6 Ma, which is in agreement with the post-collisional Acampamento Velho Formation volcanism in the Bom Jardim Group of the Camaquã Basin. A poorly constrained age of 558+/- 39Ma was obtained for rhyolites from the low-Ti group at the Picados Hill, which may indicate a younger acid volcanism, or a greater time span for the volcanism of the Acampamento Velho Formation in southernmost Brazil. Regarding magmatic sources, Sm/Nd isotopic data coupled to Pb isotopes and a review of trace element geochemistry indicate different amounts of Paleoproterozoic (Dom Feliciano, Pinheiro Machado Suite) to Neoproterozoic (Rio Vacacaí terrane) lower crust melting. Our data, coupled with literature data, contribute to a better understanding of the stratigraphic evolution for the Neoproterozoic post-collisional volcanic successions of the Camaquã Basin in the Sul-Rio-Grandense Shield. (author)

  7. Whole rock and discrete pyrite geochemistry as complementary tracers of ancient ocean chemistry: An example from the Neoproterozoic Doushantuo Formation, China

    Gregory, Daniel D.; Lyons, Timothy W.; Large, Ross R.; Jiang, Ganqing; Stepanov, Aleksandr S.; Diamond, Charles W.; Figueroa, Maria C.; Olin, Paul

    2017-11-01

    The trace element content of pyrite is a recently developed proxy for metal abundance in paleo-oceans. Previous studies have shown that the results broadly match those of whole rock studies through geologic time. However, no detailed study has evaluated the more traditional proxies for ocean chemistry for comparison to pyrite trace element data from the same samples. In this study we compare pyrite trace element data from 14 samples from the Wuhe section of the Ediacaran-age Doushantuo Formation, south China, measured by laser ablation inductively coupled plasma mass spectrometry with new and existing whole rock trace element concentrations; total organic carbon; Fe mineral speciation; S isotope ratios; and pyrite textural relationships. This approach allows for comparison of data for individual trace elements within the broader environmental context defined by the other chemical parameters. The results for discrete pyrite analyses show that several chalcophile and siderophile elements (Ag, Sb, Se, Pb, Cd, Te, Bi, Mo, Ni, and Au) vary among the samples with patterns that mirror those of the independent whole rock data. A comparison with existing databases for sedimentary and hydrothermal pyrite allows us to discriminate between signatures of changing ocean conditions and those of known hydrothermal sources. In the case of the Wuhe samples, the observed patterns for trace element variation point to primary marine controls rather than higher temperature processes. Specifically, our new data are consistent with previous arguments for pulses of redox sensitive trace elements interpreted to be due to marine oxygenation against a backdrop of mostly O2-poor conditions in the Ediacaran ocean-with important implications for the availability of bioessential elements. The agreement between the pyrite and whole rock data supports the use of trace element content of pyrite as a tracer of ocean chemistry in ways that complement existing approaches, while also opening additional

  8. Planet Formation

    Podolak, Morris

    2018-04-01

    Modern observational techniques are still not powerful enough to directly view planet formation, and so it is necessary to rely on theory. However, observations do give two important clues to the formation process. The first is that the most primitive form of material in interstellar space exists as a dilute gas. Some of this gas is unstable against gravitational collapse, and begins to contract. Because the angular momentum of the gas is not zero, it contracts along the spin axis, but remains extended in the plane perpendicular to that axis, so that a disk is formed. Viscous processes in the disk carry most of the mass into the center where a star eventually forms. In the process, almost as a by-product, a planetary system is formed as well. The second clue is the time required. Young stars are indeed observed to have gas disks, composed mostly of hydrogen and helium, surrounding them, and observations tell us that these disks dissipate after about 5 to 10 million years. If planets like Jupiter and Saturn, which are very rich in hydrogen and helium, are to form in such a disk, they must accrete their gas within 5 million years of the time of the formation of the disk. Any formation scenario one proposes must produce Jupiter in that time, although the terrestrial planets, which don't contain significant amounts of hydrogen and helium, could have taken longer to build. Modern estimates for the formation time of the Earth are of the order of 100 million years. To date there are two main candidate theories for producing Jupiter-like planets. The core accretion (CA) scenario supposes that any solid materials in the disk slowly coagulate into protoplanetary cores with progressively larger masses. If the core remains small enough it won't have a strong enough gravitational force to attract gas from the surrounding disk, and the result will be a terrestrial planet. If the core grows large enough (of the order of ten Earth masses), and the disk has not yet dissipated, then

  9. Galaxy Formation

    Longair, Malcolm S

    2008-01-01

    This second edition of Galaxy Formation is an up-to-date text on astrophysical cosmology, expounding the structure of the classical cosmological models from a contemporary viewpoint. This forms the background to a detailed study of the origin of structure and galaxies in the Universe. The derivations of many of the most important results are derived by simple physical arguments which illuminate the results of more advanced treatments. A very wide range of observational data is brought to bear upon these problems, including the most recent results from WMAP, the Hubble Space Telescope, galaxy surveys like the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, studies of Type 1a supernovae, and many other observations.

  10. Galaxy formation

    Gribbin, J.

    1979-01-01

    The current debate on the origin and evolution of galaxies is reviewed and evidence to support the so-called 'isothermal' and 'adiabatic' fluctuation models considered. It is shown that new theories have to explain the formation of both spiral and elliptical galaxies and the reason for their differences. It is stated that of the most recent models the best indicates that rotating spiral galaxies are formed naturally when gas concentrates in the centre of a great halo and forms stars while ellipticals are explained by later interactions between spiral galaxies and merging, which can cancel out the rotation while producing an elliptical galaxy in which the stars, coming from two original galaxies, follow very elliptical, anisotropic orbits. (UK)

  11. Habit formation.

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network.

  12. Habit formation

    Smith, Kyle S.; Graybiel, Ann M.

    2016-01-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network. PMID:27069378

  13. Risco de contaminação do corante azul de tripano após primeira utilização Risk of contamination of trypan blue dye after first use

    João Baptista Nigro Santiago Malta

    2006-02-01

    Full Text Available OBJETIVOS: Determinar o potencial risco de contaminação do frasco de azul de tripano (AT depois de utilizado pela primeira vez e estocado em diferentes condições de temperatura e umidade, assim como identificar os possíveis fatores de contaminação, microrganismos mais freqüentemente envolvidos e simultaneamente avaliar as propriedades bacteriostáticas e bactericidas do corante. MÉTODOS: Realizado estudo experimental, prospectivo, em que 30 frascos de AT foram divididos em três grupos (A: controle, B: armazenamento em geladeira e C: armazenamento em armário. O corante era aspirado e semeado em placas de ágar sangue e tubo de ágar Sabouraud. No grupo A o AT foi semeado apenas logo após a abertura dos frascos (tempo zero - T0, nos grupos B e C ocorreu semeadura nos T0, T1 (1 dia, T2 (2 dias, T7 (7 dias e T10 (10 dias após abertura dos frascos. No 10º dia os frascos dos grupos B e C também foram submetidos a um raspado do lado interno do frasco após abertura. Concomitantemente foi realizado teste de ação inibitória do corante AT para estudo da atividade bacteriostática e bactericida. RESULTADOS: As semeaduras realizadas no T0 não apresentaram contaminação. Entre os T1 e T10 mais o raspado houve apenas 1 frasco contaminado armazenado em geladeira. O microrganismo encontrado foi o Aspergillus niger. Foi comprovado que o corante não apresenta ação bactericida e bacteriostática para as bactérias testadas. CONCLUSÕES: Nas condições do estudo não houve contaminação dos frascos armazenados em armário e 1 frasco (10% armazenado em geladeira apresentou contaminação após abertura e uso inicial. A fonte de contaminação talvez seja o lado externo do produto. O AT não apresenta propriedades bactericidas e bacteriostáticas para as bactérias testadas e na concentração utilizada.PURPOSE: To determine the potential risk of contamination of a trypan blue bottle (TB after first use and after being stored under different

  14. Geology, petrology and U-Pb geochronology of Serra da Rajada Granitic Pluton: implications about ediacaran magmatic evolution in NE portion of the Rio Piranhas-Serido Domain (NE of Borborema Province); Geologia, petrologia e geocronologia U-Pb do Pluton Granitico Serra da Rajada: implicacoes sobre a evolucao magmatica ediacarana na porcao do Dominio Rio Piranhas-Serido (NE da Provincia Borborema)

    Costa, Alan Pereira da; Dantas, Alexandre Ranier, E-mail: alan.costa@cprm.gov.br, E-mail: alexandre.dantas@cprm.gov.br [Servico Geologico do Brasil (CPRM), Natal, RN (Brazil). Nucleo de Apoio de Natal/Superintendencia Regional de Recife; Nascimento, Marcos Antonio Leite do; Galindo, Antonio Carlos, E-mail: marcos@geologia.ufrn.br, E-mail: galindo@geologia.ufrn.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Departamento de Geologia

    2015-12-15

    The Ediacaran plutonic activity, related to the Brazilian/Pan-African orogeny, is one of the most important geological features in the Borborema Province, formed by batholiths, stocks and dikes. The Serra da Rajada Granitic Pluton (SRGP), located in the central portion of the Rio Piranhas-Serido Domain, is an example of these bodies. This site is the target of cartographic, petrographic, lithochemical and geochronological studies. Its rocks are described as monzogranites consisting of K-feldspar, plagioclase (oligoclase-An{sub 23-24%}), quartz and biotite (main mafic), having as accessory minerals opaque, titanite, allanite, apatite and zircon. Chlorite, white mica and carbonate are alteration minerals. Lithochemical data from 15 samples show quite evolved rocks (SiO{sub 2} , 69% to 75%), rich in alkalis (Na{sub 2}O + K{sub 2}O ≥ 8.0%), depleted in MgO (≤ 0.45%), CaO (≤ 1.42%) and TiO{sub 2} (≤ 0.36%), and displaying moderate levels of Fe{sub 2}O{sub 3} t (2.16 to 3.53%). These rocks present a transitional nature between metaluminous and peraluminous (predominance of the latter) and have subalkaline/monzonitic affinity (high-K Calc-alkaline). Harker diagrams represent negative correlations in Fe{sub 2}O{sub 3}t, MgO and CaO, indicating fractionation of mafic and plagioclase. The REE spectrum show enrichment of light in relation to heavy REE (LaN/YbN = 23.70 to 10.13), with negative anomaly in Eu (Eu/ Eu* = 0.70 to 10.13) suggesting fractionation or accumulation in the feldspars source (plagioclase). Data integration allows correlating the SRGP rocks with those described as Equigranular high-K Calc-alkaline Suite. The U-Pb geochronology and Sm-Nd isotope dating indicate that the biotite monzogranite have a crystallization age of 557 ± 13 Ma and TDM model age of 2.36 Ga, respectively, and ε{sub Nd} value of - 20.10 for the crystallization age, allowing to infer a crustal source for the magma generated in the Paleoproterozoic age. (author)

  15. A influência do azul de metileno na prevenção da lesão pulmonar após isquemia-reperfusão intestinal The role of the methylene blue as a lung protector after intestinal ischemia and reperfusion

    Fernando Hintz Greca

    2004-08-01

    Full Text Available OBJETIVO: Estudar a ação do azul de metileno como supressor da produção de radicais livres de oxigênio, atuando como receptor alternativo de elétrons na enzima xantina oxidase. MÉTODOS: Foram utilizados 32 ratos Wistar (Rattus norvegicus albinus, Rodentia mammalia divididos em 2 grupos de 16 animais, os quais foram denominados grupos: experimento e controle. Ambos os grupos foram submetidos a laparotomia mediana e oclusão da artéria mesentérica cranial por 60 minutos. A reperfusão foi confirmada por meio da verificação do reaparecimento da pulsação na arcada mesentérica. Foi então administrado no grupo experimento 2 ml de azul de metileno 1 % estéril intraperitonealmente, enquanto que no grupo controle foi administrado solução salina isotônica estéril em mesmo volume e pela mesma via de administração. Após 4 horas de reperfusão, os animais foram sacrificados. Amostras dos pulmões foram obtidas para: análise histopatológica, avaliação do edema e para determinação da atividade da xantina oxidase. RESULTADOS: O dano pulmonar encontrado no grupo controle foi superior ao encontrado no grupo experimento. Observou-se uma maior formação de edema nos pulmões do grupo controle. A atividade da xantina oxidase foi semelhante em ambos os grupos. CONCLUSÃO: O azul de metileno diminui a lesão pulmonar após isquemia-reperfusão intestinal.PURPOSE: To study the role of methylene blue as an inibitor of superoxide production by xantine oxidase. METHODS: Thirty two Wistar rats were divided in 2 groups of 16 animals: the control group and the experimental group. All the animals were submitted to a laparotomy for the occlusion of the cranial mesenteric artery during 60 minutes. The reperfusion was confirmed by the 'pulsation of the artery after releasing the temporary ligature. In the animals of the control group, 2 ml of saline were injected in the peritoneal cavity and in the animals of the experimental group 2 ml of methylene

  16. Cruz azul y escudo azul, centro de servicio - Carolina del Norte – (EE. UU.

    Odell, -

    1975-03-01

    Full Text Available This building is situated at the Chapel Hill-Durham road and contains the installations of two important merged insurance companies. The shape has not been chosen at random but is subject to certain conditions, such as protection from sun rays and strong winds. Neither should it be forgotten that this type of construction has a certain public relations mission to fulfill. Further, there was a great need for isolation from the noise of the traffic in the area. Metal structure, installations of all kinds and greatest consideration for the surrounding nature and the trees were dominant design factors.Este edificio está situado junto a la carretera Ciiapel Hill-Durliam y alberga las instalaciones de dos importantes compañías de seguros fusionadas. Su forma no es caprichosa, sino que obedece a motivaciones de tipo estructural, como protección de los rayos solares y de los vientos dominantes, sin olvidar la misión de reclamo publicitario que suele ser característica de este tipo de construcciones, así como lograr un cierto aislamiento del ruido que produce el tráfico rodado de la carretera próxima. Estructura metálica, cerramientos de muros - cortina, toda suerte de modernas instalaciones y máximo respeto del entorno natural y arbóreo existente.

  17. The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

    Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

    1995-04-01

    The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

  18. The advent of animals: The view from the Ediacaran

    Droser, Mary L.; Gehling, James G.

    2015-04-01

    Patterns of origination and evolution of early complex life on this planet are largely interpreted from the fossils of the Precambrian soft-bodied Ediacara Biota. These fossils occur globally and represent a diverse suite of organisms living in marine environments. Although these exceptionally preserved fossil assemblages are typically difficult to reconcile with modern phyla, examination of the morphology, ecology, and taphonomy of these taxa provides keys to their relationships with modern taxa. Within the more than 30 million y range of the Ediacara Biota, fossils of these multicellular organisms demonstrate the advent of mobility, heterotrophy by multicellular animals, skeletonization, sexual reproduction, and the assembly of complex ecosystems, all of which are attributes of modern animals. This approach to these fossils, without the constraint of attempting phylogenetic reconstructions, provides a mechanism for comparing these taxa with both living and extinct animals.

  19. Rates of star formation

    Larson, R.B.

    1977-01-01

    It is illustrated that a theoretical understanding of the formation and evolution of galaxies depends on an understanding of star formation, and especially of the factors influencing the rate of star formation. Some of the theoretical problems of star formation in galaxies, some approaches that have been considered in models of galaxy evolution, and some possible observational tests that may help to clarify which processes or models are most relevant are reviewed. The material is presented under the following headings: power-law models for star formation, star formation processes (conditions required, ways of achieving these conditions), observational indications and tests, and measures of star formation rates in galaxies. 49 references

  20. Why adult formation

    Andrej Justinek

    1997-01-01

    Full Text Available The article argues that the primary aim of adult formation is comprehensive personality development which is supposed to ensure quality existence in modern world. The article also suggests that formarion is a permanent process. Justinek puts special emphasis on adult formation methodology and defines fundamental formation styles which encourage independent action in individuals. Justinek differentiates between formation and education. methods and concludes that formation methods are related to the emotional sphere of personality, and education methods mostly to the rational. Justinek believes that formation of adults is based primarily on appropriate formation methodology.

  1. Formate Formation and Formate Conversion in Biological Fuels Production

    Bryan R. Crable

    2011-01-01

    Full Text Available Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production.

  2. Methylene blue improves hemodynamic shock but increases lipoperoxidation in severe acute pancreatitis pig model Azul de metileno melhora as condições hemodinâmicas do choque circulatório, mas aumenta a peroxidação lipídica em um modelo suino de pancreatite aguda grave

    Roberto Ferreira Meirelles Jr

    2008-01-01

    Full Text Available PURPOSE: Study hemodynamic pattern and lipoperoxidation during methylene blue (MB treatment on taurocholate - enterokinase induced acute pancreatitis (AP. METHODS: Thirty pigs were equally divided in control group; MB group; AP group; MB previous AP group; and MB after 90 min of induced AP group. MB was given iv in a bolus dose (2mg.kg-1 followed by maintenance dose (2 mg.kg-1.h-1. Hemodynamic parameters were recorded continuously during 180 min by Swan-Ganz catheter. Blood samples were taken every 60 min to determine arterial and venous nitrate, malondialdehyde (MDA and amylase. Pancreatic tissue was removed for histopathologic study. RESULTS: In AP group MBP and CO decreased over time 33% (p0.05 serum MDA when associated to AP. After induced AP, MB did not reverse MBP and CO decrease. There was no difference in serum amylase and necro-hemorrhagic findings with MB treatment. CONCLUSIONS: In this taurocholate-induced AP model MB treatment delayed hemodynamic shock and decreases serum nitrate levels but increases serum MDA levels. No volemic replacement was done and it may have been a mitigated factor to a poor tissue perfusion and impairment microcirculation. Further investigations are needed to elucidate MB treatment role during AP treatment.OBJETIVO: estudar o perfil hemodinâmico e a lipoperoxidação durante o tratamento com azul de metileno (AM de pancreatite aguda (PA induzida por taurocolato-enteroquinase. MÉTODOS: Trinta porcos foram igualmente divididos em: grupo controle, grupo AM; grupo PA; grupo AM prévio à PA; grupo AM após 90 minutos após a indução da PA. O AM foi administrado sob a forma de bolus EV (2mg.kg-1 seguido por dose de manutenção (2 mg.kg-1.h-1. Os parâmetros hemodinâmicos foram registrados continuamente durante 180 min com auxílio de cateter de Swan-Ganz. Amostras sanguíneas foram colhidas a cada 60 min para a determinação arterial e venosa de nitrato, malondialdeido (MDA and amilase. Removeu-se tecido

  3. Determinação e análise de isotermas de adsorção do corante azul 5G em leito fixo de carvão ativado=Mathematical model of the adsorption column, in activate Carbon, used in the renovation of blue-colorant 5G

    Jorge Antonio Lopes Dal Piva

    2011-10-01

    Full Text Available Visando o desenvolvimento de um processo de tratamento de efluentes têxteis, este trabalho teve por objetivo estudar o processo de adsorção do corante reativo azul 5G de um efluente sintético em carvão ativado. As isotermas de adsorção, com seus respectivos parâmetros ajustados, em sistema batelada foram obtidas para as temperaturas de 30, 40 e 60C (com pH controlado na faixa de 6,0 a 8,0 e também com tempo de contato entre o sistema corante-carvão de 90 horas segundo os modelos de Langmuir e Freundlich. A partir daí estes parâmetros foram colocados em função da temperatura, apresentando bons resultados frente aos dados experimentais.This work, to looking for the development of process for wastes textile treatment, had the objective to study the adsorption process of the blue reactive dyes 5G from the synthetic effluent in coal activated. The isotherms of adsorption in batch system was made for temperatures of 30, 40 and 60C (the pH was controlled in 6.0 until 8.0 and the time of contact between the system dye-coal was 90 hours with posterior adjustment of the models for Langmuir and Freundlich equations. After, these parameters were put in function of temperature, with good results when compared to the experimental data.

  4. FORMATION CONSTANTS AND THERMODYNAMIC ...

    KEY WORDS: Metal complexes, Schiff base ligand, Formation constant, DFT calculation ... best values for the formation constants of the proposed equilibrium model by .... to its positive charge distribution and the ligand deformation geometry.

  5. Theory of aurora formation

    Hasegawa, Akira.

    1975-04-01

    A new theory of aurora formation is presented based on Alfven wave-electron interaction. The theory explains consistently 1) the electron acceleration process, 2) the formation of auroral layers and 3) the long wave formation in the longitudinal direction. (auth.)

  6. Use of ZnO:Mn particles for degradation of methylene blue by photocatalysis process; Utilizacao de particulas de ZnO:Mn para a degradacao do azul de metileno por processo de fotocatalise

    Giraldi, T. R.; Swerts, J. P.; Vicente, M. A., E-mail: tania.giraldi@unifal-mg.edu.br, E-mail: jefersonps21@hotmail.com, E-mail: maquelyaspr@oi.com.br [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil). Instituto de Ciencia e Tecnologia; Mendonca, V.R. de, E-mail: vrm@ifsp.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Sao Paulo (IFSP), Itapetininga, SP (Brazil); Paris, E.C.; Ribeiro, C., E-mail: elaine.paris@embrapa.br, E-mail: caue.ribeiro@embrapa.br [Embrapa Instrumentacao, Sao Carlos, SP (Brazil)

    2016-10-15

    The management of water use in the agricultural environment is a key factor to build new environmentally sustainable productive methods. Photocatalysis is a promising method for water decontamination. This research paper aimed to evaluate the photocatalytic potential of pure and Mn-doped ZnO particles. The materials were obtained by the polymeric precursor method, and characterized by X-ray diffraction, N{sub 2} adsorption in low temperature, infrared and ultraviolet spectroscopy, and photoluminescence. In order to evaluate ZnO:Mn particles photo efficiency, experiments were carried out by applying the methylene blue dye solution to photodegradation under UVC exposure. The particles had ZnO single-phase, but low specific surface area. The sample ZnO:0.25% Mn presented higher efficiency in the methylene blue photocatalytic degradation test. This efficiency was related to a higher band gap energy value and a lower rate of electron recombination, which allows greater formation of hydroxyl radicals, which are responsible for dye degradation. (author)

  7. U-Pb age constraints for the La Tuna Granite and Montevideo Formation (Paleoproterozoic, Uruguay): Unravelling the structure of the Río de la Plata Craton

    Pamoukaghlián, Karina; Gaucher, Claudio; Frei, Robert; Poiré, Daniel G.; Chemale, Farid; Frei, Dirk; Will, Thomas M.

    2017-11-01

    The Río de la Plata Craton is a continental block that crops out in Uruguay, eastern Argentina, southernmost Brazil and Paraguay. It comprises in Uruguay the Piedra Alta, Tandilia and Nico Pérez terranes, separated by the Colonia and the Sarandí del Yí megashears. The La Tuna Granite, which intrudes the Araminda metasandstones in the Tandilia Terrane, was considered Cambrian in age and the intruded sandstones were assigned to the Neoproterozoic Piedras de Afilar Formation. We show that the granite is Paleoproterozoic in age and that the host metasandstones do not belong to the Piedras de Afilar Formation, but to the Paleoproterozoic Montevideo Formation. U-Pb LA ICP-MS of zircon ages for the La Tuna Granite yielded a concordant crystallization age of 2156 ± 26 Ma. Furthermore a metamorphic event at 2010 ± 9 Ma is revealed by Pb stepwise leaching dating of monazites. U-Pb detrital zircon ages of the host Araminda metasandstone yield an upper intercept discordia age of 2152 ± 29 Ma, which marks the intrusion of the La Tuna pluton, and which is in accordance with the zircon U-Pb LA ICP MS constraints. A concordant U-Pb detrital zircon age of 2465 ± 40 Ma provides a maximum depositional age constraint for the metapsammites. Comparing quartz arenites of the Ediacaran Piedras de Afilar Formation with the Araminda metaquartzites, we conclude that they are very similar regarding petrology but they differ in age and metamorphic overprint. Detrital zircons in quartz arenites of the Piedras de Afilar Formation show youngest ages of 1.0 Ga. On the other hand, detrital zircons recovered from the Araminda metasandstones and the age of the intruding granite allow interpreting a depositional age between 2465 and 2150 Ma. Nd model ages show crustal residence times in average more than 200 myr older for the Tandilia Terrane both in Uruguay and Argentina, with a significant Neoarchean component, which is lacking in the Piedra Alta Terrane. Whereas the Piedra Alta Terrane was

  8. Box-Behnken design for optimizing the acid blue dye adsorption on flower wastes Diseño Box-Behnken para la optimización de la adsorción del colorante azul ácido sobre residuos de flores

    Ana Cristina Jaramillo Madrid

    2013-11-01

    Full Text Available In this paper we identified the best conditions for the removal of Acid Blue 9 dye (AB9 using ower wastes (FW as an adsorbent were determined using a full factorial 23 and a Box-Behnken design for further optimization. Adsorbent dose (D, dye concentration (C and contact time (t, were the assessed variables. The dye content was quantied by UV-Vis spectrometry. The statistical model presented an adequate adjustment coecient (R2 = 99,18%, allowing to achieve a removal of 98,5% with a dosage of 7,8 gL-1, dye concentration of 7,11 mgL-1 and contact time of 104 min. These results suggest that owers wastes are an alternative and potential adsorbent material for the treatment of dissolved acid dyes. En este artículo se determinaron las mejores condiciones para la remoción del colorante Azul Ácido 9 (AA9 a través de un diseño factorial completo 23 y su posterior optimización mediante un diseño de superficie Box-Behnken utilizando tallos de flores (TF como material adsorbente. Las variables evaluadas fueron dosis de adsorbente (D, concentración de colorante (C y tiempo de contacto (t. El contenido del colorante se cuantificó por espectrometría UV-Vis. El modelo estadístico presentó un adecuado coeficiente de ajuste (R2 = 99,18 %, permitiendo alcanzar una remoción del 98,5% con una dosificación de 7,8 gL-1, concentración de colorante de 11,7 mgL-1 y tiempo de contacto de 104 min. Estos resultados sugieren que los residuos de flores constituyen un material adsorbente alternativo y potencial para el tratamiento de colorantes ácidos disueltos.

  9. Necesidades de aprendizaje relacionados con el cáncer bucal en un círculo de abuelos de Ciudad de La Habana Learning needs related to oral cancer in "Isla Azul" grandparents home, Plaza de la Revolución Municipality. 2007

    Gilda L García Heredia

    2009-12-01

    Full Text Available El envejecimiento en las personas está asociado a la aparición o aumento de afecciones estomatológicas, entre ellas las alteraciones periodontales, disfunción masticatoria y el cáncer bucal, esta última enfermedad es la de mayor incidencia en la población adulta mayor y su prevención ocupa un lugar importante en la atención primaria de salud, por ello se realizó una investigación cuyo objetivo fue determinar las necesidades de aprendizaje relacionadas con el cáncer bucal en el Círculo de Abuelos "Isla Azul" en el año 2007. Se realizó una investigación de desarrollo tecnológico, descriptiva, de corte transversal para el diagnóstico educativo. Se aplicó una encuesta a 26 ancianos y se determinaron las necesidades de aprendizaje mediante el modelo de David Leyva. El 73 % de los encuestados obtuvo calificación deficiente. Se encontró bajo nivel de conocimiento de los factores de riesgo del cáncer bucal, deficiencias en las vías de información educativa, desconocimiento de los síntomas y signos de alarma ante el cáncer bucal. No realizaban adecuadamente el autoexamen bucal, por lo que consideramos que existieron necesidades de aprendizaje sobre prevención del cáncer bucal en todos los aspectos explorados.Aging in persons it is associated with appearance or increase of stomatologic affections including the periodontal alterations, mastication dysfunction and oral cancer, this entity with the great incidence in elderlies and its prevention is a priority in Health Primary Care, thus, we conducted a research in elderlies linked to a grandparent home whose objective was to determine the learning needs related to oral hygiene in above mentioned home in 2007. A technological development, descriptive and cross-sectional research to an educational diagnosis. A survey was applied in 26 elderlies determining the learning needs by David Leyva Form. The 73 % of person polled had a qualification of deficient. In he above mentioned home

  10. Stages of ores formation

    Khasanov, A.Kh.

    1988-01-01

    Deposit formation (especially endogenous) is the complicated, multi-stage and long process. Establishment of deposit formation succession, age-specific correlations of minerals and aggregates have a high importance at solving genetic questions. Studying of minerals correlations and mineral aggregates, succession of their crystallization and other observations let restore the history of deposit formation, pick up in it different on duration and physical and chemical conditions stages

  11. Planet formation in Binaries

    Thebault, Ph.; Haghighipour, N.

    2014-01-01

    Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review her...

  12. Data format translation routines

    Burris, R.D.

    1981-02-01

    To enable the effective connection of several dissimilar computers into a network, modification of the data being passed from one computer to another may become necessary. This document describes a package of routines which permit the translation of data in PDP-8 formats to PDP-11 or DECsystem-10 formats or from PDP-11 format to DECsystem-10 format. Additional routines are described which permit the effective use of the translation routines in the environment of the Fusion Energy Division (FED) network and the Elmo Bumpy Torus (EBT) data base

  13. ENDF/B format

    Khalil, M.A.; Lemmel, H.D.

    1986-09-01

    This document is a brief user's description of the format of ENDF/B. This format, originally designed for the US Evaluated Nuclear Data File, is recommended for international use. This summary is an aid to customers of the IAEA Nuclear Data Section when receiving data retrievals in ENDF/B format. For more detailed information the report BNL-NCS-50496 (ENDF 102) should be consulted. An Appendix to the present document gives a summary of the format differences between ENDF/B-4 and ENDF/B-5. (author)

  14. Exploring Opponent Formats

    Jensen, Mads Møller; Rasmussen, Majken; Grønbæk, Kaj

    2013-01-01

    of how the opponent format and relationships impact a game are almost absent in current research. Thus, this paper aims to elucidate how the perception of a competition differs, depending on the opponent format, by presenting a game mechanic framework. The paper furthermore presents an interactive...... football-training platform, as well as games designed to explore the different opponent formats. The games are qualitatively evaluated to illuminate the qualities of and distinctions between different types of opponent formats, proposed by the framework terminology....

  15. ENDF/B Format

    Khalil, M.A.

    1975-01-01

    This document is a brief user's description of the format of ENDF/B, the evaluated neutron nuclear data library of the US National Nuclear Data Center. This summary is an aid to customers of the IAEA Nuclear Data Section when receiving data retrievals in ENDF/B format. For more detailed information the report BNL-50274 (ENDF-102) should be consulted. (author)

  16. Formation of multiple networks

    Magnani, Matteo; Rossi, Luca

    2013-01-01

    we introduce the first network formation model for multiple networks. Network formation models are among the most popular tools in traditional network studies, because of both their practical and theoretical impact. However, existing models are not sufficient to describe the generation of multiple...

  17. Methylene blue administration in the compound 48/80-induced anaphylactic shock: hemodynamic study in pigs Administração de azul de metileno no choque anafilático induzido por composto 48/80: estudo hemodinâmico em suínos

    Antonio Carlos Menardi

    2011-12-01

    Full Text Available PURPOSE: To verify if the methylene blue (MB administration prevents and/or reverses the compound 48/80 (C48/80-induced anaphylactic shock in pigs. METHODS: Female Dalland pigs were anesthetized and had the hemodynamic parameters recorded during the necessary time to administer some drugs and observe their effect. The animals were randomly assigned to one of the five groups: 1 control; 2 MB: the animals received a bolus injection of MB (2 mg/kg followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump; 3 C48/80: the animals received a bolus injection of C48/80 (4 mg/kg; 4 C48/80+MB: the animals received a bolus injection of C48/80 (4 mg/kg and 10 minutes after the C48/80 administration the animals received a bolus injection of MB (2 mg/kg followed by continuous infusion of MB (2.66 mg/Kg/h delivered by syringe infusion pump; 5 MB+C48/80: the animals received a bolus injection of MB (2 mg/kg and 3 minutes later they received a bolus injection of C48/80 (4 mg/kg. RESULTS: The intravenous infusion of MB alone caused no changes in the mean arterial pressure (MAP showing that the administered MB dose was safe in this experimental model. The C48/80 was effective in producing experimental anaphylactic shock since it was observed a decrease in both MAP and cardiac output (CO after its administration. The MB did not prevent or reverse the C48/80-induced anaphylactic shock in this model. In fact, the MAP of the animals with anaphylactic shock treated with MB decreased even more than the MAP of the animals from the C48/80 group. On the other hand, the C48/80-induced epidermal alterations disappeared after the MB infusion. CONCLUSION: Despite our data, the clinical manifestations improvement brings some optimism and does not allow excluding the MB as a possible therapeutic option in the anaphylactic shock.OBJETIVO: Verificar se a administração de azul de metileno (AM previne e/ou reverte o choque anafilático induzido por

  18. From Sermon Formation to Preacher Formation

    Gaarden, Marianne

    2016-01-01

    today is less about exercising the authority of an office and more about embodying authenticity. I argue that traditional homiletic education can benefit from implementing a learner-centered approach to teaching moving from sermon formation towards preacher formation, in order to develop and train...... preachers. This involves a learning strategy to ministry where theological skills, pastoral competences, and own personality are interwoven. Teaching here means facilitating a room of learning where teacher’s power and control is reduced, allowing the preacher to reflect upon own practice without being...... judged, evaluated, or critiqued. In this paper, I explain how a learner-centered approach to education works in practice and show how pastors experience the teaching method and the congregations’ positive response to their improvements. I shall present the results of a focus-group interview with pastors...

  19. Usage Record Format Recommendation

    Nilsen, J.K.; Muller-Pfeerkorn, R

    2013-01-01

    For resources to be shared, sites must be able to exchange basic accounting and usage data in a common format. This document describes a common format which enables the exchange of basic accounting and usage data from different resources. This record format is intended to facilitate the sharing of usage information, particularly in the area of the accounting of jobs, computing, memory, storage and cloud usage but with a structure that allows an easy extension to other resources. This document describes the Usage Record components both in natural language form and annotated XML. This document does not address how these records should be used, nor does it attempt to dictate the format in which the accounting records are stored. Instead, it denes a common exchange format. Furthermore, nothing is said regarding the communication mechanisms employed to exchange the records, i.e. transport layer, framing, authentication, integrity, etc.

  20. Earth formation porosity log

    Smith, H.D.; Smith, M.P.; Schultz, W.E.

    1977-01-01

    A method for determining the porosity of earth formations in the vicinity of a cased well borehole is described, comprising the steps of: irradiating the earth formations in the vicinity of the cased well borehole with fast neutrons from a source of fast neutrons passed into the borehole; and generating a signal representative of the fast neutron population present in the well borehole at a location in the borehole, the signal is functionally related to the porosity of the earth formations in the vicinity of the borehole

  1. Manuel UNIMARC format bibliographique

    2007-01-01

    This manual is the French translation of the second edition of UNIMARC Manual: bibliographic format published in English in 1994 and completed by 5 updates published from 1996 to 2005. This 5th French edition is composite. It reproduces identically a part of the 4th edition published in 2002 and, for the fields of the format modified in the Update 5, it offers a new more structured presentation. This is a handbook dedicated to French-speaking users of the UNIMARC format for bibliographic descriptions.

  2. Reconsidering formative measurement.

    Howell, Roy D; Breivik, Einar; Wilcox, James B

    2007-06-01

    The relationship between observable responses and the latent constructs they are purported to measure has received considerable attention recently, with particular focus on what has become known as formative measurement. This alternative to reflective measurement in the area of theory-testing research is examined in the context of the potential for interpretational confounding and a construct's ability to function as a point variable within a larger model. Although these issues have been addressed in the traditional reflective measurement context, the authors suggest that they are particularly relevant in evaluating formative measurement models. On the basis of this analysis, the authors conclude that formative measurement is not an equally attractive alternative to reflective measurement and that whenever possible, in developing new measures or choosing among alternative existing measures, researchers should opt for reflective measurement. In addition, the authors provide guidelines for researchers dealing with existing formative measures. Copyright 2007 APA, all rights reserved.

  3. Isothermal Martensite Formation

    Villa, Matteo

    Isothermal (i.e. time dependent) martensite formation in steel was first observed in the 40ies of the XXth century and is still treated as an anomaly in the description of martensite formation which is considered as a-thermal (i.e. independent of time). Recently, the clarification of the mechanism...... of lattice strains provided fundamental information on the state of stress in the material and clarified the role of the strain energy on martensite formation. Electron backscatter diffraction revealed that the microstructure of the material and the morphology of martensite were independent on the cooling...... leading to isothermal kinetics acquired new practical relevance because of the identification of isothermal martensite formation as the most likely process responsible for enhanced performances of sub-zero Celsius treated high carbon steel products. In the present work, different iron based alloys...

  4. Cosmology and galaxy formation

    Rees, M.J.

    1977-01-01

    Implications of the massive halos and ''missing mass'' for galaxy formation are addressed; it is suggested that this mass consists of ''Population III'' stars that formed before the galaxies did. 19 references

  5. Fracturing formations in wells

    Daroza, R A

    1964-05-15

    This well stimulation method comprises introducing through the well bore a low-penetrating, dilatant fluid, and subjecting the fluid to sufficient pressure to produce fractures in the formation. The fluid is permitted to remain in contact with the formation so as to become diluted by the formation fluids, and thereby lose its properties of dilatancy. Also, a penetrating fluid, containing a propping agent suspended therein, in introduced into contact with the fractures at a pressure substantially reduced with respect to that pressure which would have been required, prior to the fracturing operation performed using the low-penetrating dilatant fluid. The propping agent is deposited within the fractures, and thereafter, fluid production is resumed from the fractured formation. (2 claims)

  6. Star formation: Cosmic feast

    Scaringi, Simone

    2017-03-01

    Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

  7. PCF File Format.

    Thoreson, Gregory G [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    PCF files are binary files designed to contain gamma spectra and neutron count rates from radiation sensors. It is the native format for the GAmma Detector Response and Analysis Software (GADRAS) package [1]. It can contain multiple spectra and information about each spectrum such as energy calibration. This document outlines the format of the file that would allow one to write a computer program to parse and write such files.

  8. Plant Formate Dehydrogenase

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  9. Purpura, verde, azul...la calidad como un color

    Lorenzo Ramírez, Nuria

    2009-01-01

    El objetivo de este artículo es explicar, compartir y hacer públicos algunos pensamientos e ideas sobre la Universidad y la cultura del profesorado universitario. Se parte de la idea de que no existe armonía entre la gestión, la técnica y la cultura universitaria. Si como docentes aprendemos de la experiencia y del ambiente de trabajo, entonces cabe preguntarse por nuestras experiencias y por los conocimientos que a travcs de ellas hemos generado, para mantenerlos o rechazar...

  10. Sinfonía en verde y azul

    Javier Moscarella

    1982-10-01

    Full Text Available La rica región esmeraldífera de Muzo, ha dado inmenso prestigio a Colombia en el exterior: las esmeraldas que allí se han encontrado son las más hermosas del mundo y sus tamaños han superado muchas veces la imaginación de las mentes más afiebradas; pero no solo las esmeraldas han hecho famoso el nombre de la provincia de Muzo, se encuentran allí también unas mariposas de singular belleza y colorido que han cautivado la atención de algunos importantes poetas latinoamericanos.

  11. Un caso de aorta destrocardica o enfermedad azul permanente

    Héctor Pedraza

    1935-11-01

    Full Text Available Se trata del niño E. S. de 28 meses de edad, que fue recibido por uno de nosotros en el Hospital de La Misericordia en los primeros días de mayo de 1935. El padre, oriundo, como su hijo, de la hacienda de "El Chocho", en el municipio de Fusagasugá, lo trajo a Bogotá con el objeto de que su hijo mejorara de una afección que la sufría permanentemente y desde los primeros momentos de su vida. El padre nos refiere que jamás el niño ha podido comer por más de unos cinco minutos, que el simple ejercicio de la succión del pezón de la madre o del chupo lo fatiga, que tiene que descansar cada momento, en tal forma que nunca queda satisfecho su apetito. Tampoco puede dormir tranquilo; varias veces, durante la noche o el día, se despierta asustado, fatigoso, sobresaltado. Dice que desde que nació le ha notado un tinte morado en los tegumentos y especialmente en las uñas, labios y en las conjuntivas oculares, color que lo ve aumentarse cuando el niño hace el ejercicio natural para comer o cuando se despierta repentinamente del sueño en que estaba. Además nota que el desarrollo no le satisface, es poco relativamente lo que ha crecido, tiene ya 28 meses y los padres se muestran afanosos porque no puede caminar y apenas trata de sentarse; los miembros, poco desarrollados, y su dentición comenzó únicamente a los 14 meses.

  12. Esferas de quitosana/Fe na degradação do corante Azul QR-19 por processos foto-Fenton utilizando luz artificial ou solar Chitosan/Fe spheres on the Blue QR-19 dye degradation by photo Fenton processes using artificial or solar light

    Kely V. de Souza

    2010-09-01

    Full Text Available A contaminação dos recursos hídricos é um dos maiores problemas ambientais da atualidade. Dentre as várias fontes poluidoras, destacam-se as indústrias têxteis, por serem fontes geradoras de grandes volumes de efluentes, muitas vezes tratados de maneira ineficiente. A principal causa do grande impacto ambiental decorrente deste descarte é a presença dos corantes, tais como os compostos do tipo azo, que podem gerar subprodutos de caráter carcinogênico e/ou mutagênico, ou como os de base antraquinona, que são muito resistentes à degradação natural e portanto persistem no efluente por um longo tempo. O objetivo do presente trabalho consiste na utilização de processos foto-Fenton assistidos por luz artificial e solar, utilizando ferro imobilizado em esferas de quitosana reticulada com glutaraldeído, para promover a degradação do corante reativo Azul QR-19, de base antraquinona, em solução aquosa. As esferas obtidas apresentaram tamanho regular com diâmetro de 4,0 mm. Os resultados demonstraram 90% de descoloração do sistema em 180minutos e redução de 60% do teor de carbono orgânico total (COT, para o sistema foto-Fenton utilizando luz artificial. Para o sistema fotoassistido com luz solar, a descoloração foi integralmente obtida em 120 minutos com 70% de redução do teor de COT. Foi observado que o ferro permaneceu na matriz após o tratamento, possibilitando sua reutilização.The contamination of water resources is one of the greatest environmental problems today. Among the polluting sources are the textile industries due to the production of large volumes of effluent, often treated inefficiently. The main reason for the environmental impact of the rejected materials is the presence of dyes such as azo reactive compounds that can generate by-products with carcinogenic and mutagenic effects. They may also include anthraquinone type compounds, which are highly resistant to degradation and persist in the effluent for a

  13. Ligninolytic enzymes production and Remazol brilliant blue R decolorization by tropical brazilian basidiomycetes fungi Produção de enzimas ligninolíticas e descoloração do corante azul brilhante de Remazol R por fungos basidiomicetos tropicais brasileiros

    Kátia M. G. Machado

    2005-09-01

    Full Text Available Remazol Brilliant Blue R (RBBR dye was used as substrate to evaluate ligninolytic activity in 125 basidiomycetous fungi isolated from tropical ecosystems. The extracellular RBBR decolorizing activity produced when selected fungi were grown in solid media and in soil contaminated with organochlorines was also evaluated. A total of 106 fungi decolorized the RBBR during the growth in malt extract agar (MEA, 2%; 96 fungi showed a mycelia growth and decolorization activity stronger than the P. chrysosporium used as reference. Extracellular extracts of 35 selected fungi grown on solid medium with sugar cane bagasse (BGS were evaluated for RBBR decolorization and peroxidase activity. All fungi showed peroxidase activities, but 5 of those were unable to decolorize the RBBR. Different patterns of ligninolytic enzymes were detected in 12 fungi extracts. Mn-dependent peroxidase (MnP was produced by Peniophora cinerea, Psilocybe castanella, three strains of Trametes villosa, T. versicolor, Melanoporia nigra and Trichaptum byssogenum. All 12 fungi had laccase activity. Trogia buccinalis showed the highest RBBR decolorization and did not produce MnP activity. RBBR decolorization without MnP production was also observed for three strains of Lentinum tested. Higher levels of peroxidase and laccase cannot be related to high RBBR decolorization. RBBR decolorization by extracellular extract was also detected during the growth of P. castanella, L. crinitus, P. cinerea and two strains of T. Villosa in pentachlorophenol- and hexachlorobenzene-contaminated soils. These fungi showed higher RBBR decolorization when grown in the presence of organochlorine compounds than when in non contaminated soil.O corante azul brilhante Remazol R (RBBR foi usado como substrato para avaliar 125 fungos basidiomicetos isolados de ecossistemas tropicais brasileiros quanto a atividade ligninolítica. A descoloração do RBBR por extratos obtidos do crescimento de fungos em meio sólido e

  14. Efeitos da cobertura do solo com filme de polietileno azul no consumo de água da cultura da alface cultivada em estufa Effects of the soil covering with blue colored polyethylene film on lettuce crop consumptive water-use in a gree

    Alexandre O. Gonçalves

    2005-12-01

    Full Text Available A cobertura do solo é uma prática agrícola que visa, principalmente, a controlar as plantas invasoras, a diminuir as perdas de água por evaporação do solo e a facilitar a colheita e a comercialização, uma vez que o produto se torna mais limpo e sadio. Porém, ao se cobrir o solo, também são alterados parâmetros importantes do microclima e, conseqüentemente, a germinação das sementes, o crescimento das raízes, a absorção de água e nutrientes, a atividade metabólica das plantas e o armazenamento de carboidratos. O objetivo do presente trabalho foi avaliar o efeito da cobertura do solo com filme de polietileno azul no consumo de água da cultura da alface (Lactuca sativa L.. O experimento foi instalado em uma estufa convencional, no município de Araras - SP, e conduzido durante o período de 22-3-2001 a 1º-5-2001. O consumo de água foi medido em dois lisímetros de pesagem instalados no interior da estufa. O espaçamento da cultura foi de 0,25 m x 0,25 m. Também foi avaliado o índice de área foliar (IAF em seis épocas distintas e determinada a eficiência do uso de água (EU ao final do ciclo da cultura. O delineamento estatístico foi o de blocos inteiramente casualizados, com dois tratamentos, "solo descoberto" e "solo coberto". O consumo médio de água foi de 4,17 mm dia-1 para o tratamento "solo descoberto" e de 3,11 mm dia-1 para o tratamento "solo coberto". O índice médio de área foliar não diferiu estatisticamente entre os tratamentos.The covering of the soil is an agricultural practice that intends to control the harmful herbs, to reduce the losses of water by evaporation of the soil, and to facilitate the harvest and the commercialization, once the product is cleaner and healthier. However, when the soil is covered important microclimatic parameters are also altered, and consequently the germination of seeds, the growth of roots, the absorption of water and nutrients, the metabolic activity of the plants and

  15. Methylene blue for vasoplegic syndrome treatment in heart surgery: fifteen years of questions, answers, doubts and certainties Azul de metileno no tratamento da síndrome vasoplégica em cirurgia cardíaca: quinze anos de perguntas, respostas, dúvidas e certezas

    Paulo Roberto Barbosa Evora

    2009-09-01

    Full Text Available OBJECTIVE: There is strong evidence that methylene blue (MB, an inhibitor of guanylate cyclase, is an excellent therapeutic option for vasoplegic syndrome (VS treatment in heart surgery. The aim of this article is to review the MB's therapeutic function in the vasoplegic syndrome treatment. METHODS: Fifteen years of literature review. RESULTS: 1 Heparin and ACE inhibitors are risk factors; 2 In the recommended doses it is safe (the lethal dose is 40 mg/kg; 3 The use of MB does not cause endothelial dysfunction; 4 The MB effect appears in cases of nitric oxide (NO up-regulation; 5 MB is not a vasoconstrictor, by blocking of the GMPc system it releases the AMPc system, facilitating the norepinephrine vasoconstrictor effect; 6 The most used dosage is 2 mg/kg as IV bolus followed by the same continuous infusion because plasmatic concentrations strongly decays in the first 40 minutes; 7 There is a possible "window of opportunity" for the MB's effectiveness. CONCLUSIONS: Although there are no definitive multicentric studies, the MB used to treat heart surgery VS, at the present time, is the best, safest and cheapest option, being a Brazilian contribution for the heart surgeryOBJETIVO: Existem fortes evidências de que o azul de metileno (AM, um inibidor da guanilato ciclase, é uma excelente opção terapêutica para o tratamento da síndrome vasoplégica (SV em cirurgia cardíaca. O objetivo deste artigo é rever o papel terapêutico do AM no tratamento da SV. MÉTODOS: Revisão da literatura em período de 15 anos. RESULTADOS: 1 A heparina e inibidores da ECA são fatores de risco; 2 Nas doses preconizadas é droga segura (a dose letal é de 40 mg/kg; 3 O AM não causa disfunção endotelial; 4 O efeito do AM só aparece em caso de supra-regulação de óxido nítrico (NO; 5 O AM não é um vasoconstritor, pelo bloqueio do sistema GMPc ele "libera" o sistema AMPc, facilitando o efeito vasoconstritor da noradrenalina; 6 A dosagem mais utilizada é 2

  16. Utilização do azul de metileno no tratamento da síndrome vasoplégica após cirurgia cardíaca Methylene blue administration in the treatment of the vasoplegic syndrome after cardiac surgery

    José Carlos S. de Andrade

    1996-06-01

    Full Text Available Relata-se a restauração da resistência vascular sistêmica com o uso do azul de metileno (AM em pacientes submetidos a cirurgia cardíaca com e sem circulação extracorpórea. Todos os pacientes apresentaram no pós-operatório imediato quadro de taquicardia, oligúria, manutenção da perfusão periférica e importante hipotensão arterial sistêmica, retrataria a grandes doses de catecolaminas. As avaliações hemodinâmicas pela técnica de termodiluição com cateter de Swan-Ganz monstraram padrão compatível com síndrome vasoplégica, com índice de resistência vascular sistêmica média de 868 dina. s. cm5, sem resposta a drogas vasoativas. À semelhança do choque endotóxico, a síndrome foi interpretada como decorrente da estimulação da enzima óxido nítricosintetase com conseqüente formação de óxido nítrico (NO pelas células endoteliais. Utilizou-se então AM, como bloqueador do NO no sistemaguanililciclase/guanino-monofosfatociclase, na dose de 1,5 mg/kg peso, em infusão intravenosa por uma hora. O restabelecimento do tônus vascular sistêmico (IRVS = 1693 dina. s. cm5 com normalização da pressão arterial e do quadro clínico, foi efetivo e rápido, mostrando ser o AM uma promissora droga na diminuição da morbi-mortalidade da síndrome vasoplégica.The restoration of the systemic vascular resistance employing methylene blue (MB in 6 patients after cardiac surgery with and without cardiopulmonary bypass is reported. All patients presented, during the immediate postoperative period, tachycardia, oligury, good peripheral perfusion and important systemic arterial hypotension not responsible to large doses of catecholamines infusion. The hemodynamic analysis, using the Swan-Ganz thermodilution technique, showed a profile compatible with vasoplegic syndrome, with the mean index of systemic vascular resistance of 868 dyne.s.cm5, similarly to the endotoxic shock this syndrome was assumed to be caused by nitric oxide

  17. Blistering and bubble formation

    Roth, J.

    1976-01-01

    Blister formation in metals has been observed during bombardment with inert-gas ions in the energy range between 1 and 2000 keV at doses of about 10 17 to 10 19 cm -2 . The changes in surface topography and the erosion yields were mainly studied in the scanning electron microscope (SEM). Additionally the release of the implanted gas during blister formation was observed. Recently measurements on single crystals were performed determining simultaneously the implantation profile, the total amount of trapped ions, the depth distribution of the induced lattice damage and the thickness of the covers of the blisters. In several stages of the formation process of blisters the implanted layer was observed in the transmission electron microscope (TEM) showing the formation of gas bubbles. Using the results of all these measurements in this review an attempt is made to develop a model of blister formation combining the effects of hydrostatic pressure in the gas bubbles and lateral stress due to volume swelling. (author)

  18. Vascular lumen formation.

    Lammert, Eckhard; Axnick, Jennifer

    2012-04-01

    The vascular system developed early in evolution. It is required in large multicellular organisms for the transport of nutrients, oxygen, and waste products to and from tissues. The vascular system is composed of hollow tubes, which have a high level of complexity in vertebrates. Vasculogenesis describes the de novo formation of blood vessels, e.g., aorta formation in vertebrate embryogenesis. In contrast, angiogenesis is the formation of blood vessels from preexisting ones, e.g., sprouting of intersomitic blood vessels from the aorta. Importantly, the lumen of all blood vessels in vertebrates is lined and formed by endothelial cells. In both vasculogenesis and angiogenesis, lumen formation takes place in a cord of endothelial cells. It involves a complex molecular mechanism composed of endothelial cell repulsion at the cell-cell contacts within the endothelial cell cords, junctional rearrangement, and endothelial cell shape change. As the vascular system also participates in the course of many diseases, such as cancer, stroke, and myocardial infarction, it is important to understand and make use of the molecular mechanisms of blood vessel formation to better understand and manipulate the pathomechanisms involved.

  19. Meningococcal biofilm formation

    Lappann, M.; Haagensen, Janus Anders Juul; Claus, H.

    2006-01-01

    We show that in a standardized in vitro flow system unencapsulated variants of genetically diverse lineages of Neisseria meningitidis formed biofilms, that could be maintained for more than 96 h. Biofilm cells were resistant to penicillin, but not to rifampin or ciprofloxacin. For some strains......, microcolony formation within biofilms was observed. Microcolony formation in strain MC58 depended on a functional copy of the pilE gene encoding the pilus subunit pilin, and was associated with twitching of cells. Nevertheless, unpiliated pilE mutants formed biofilms showing that attachment and accumulation......X alleles was identified among genetically diverse meningococcal strains. PilX alleles differed in their propensity to support autoaggregation of cells in suspension, but not in their ability to support microcolony formation within biofilms in the continuous flow system....

  20. Tritiated ammonia formation

    Heung, L.K.

    1995-01-01

    When nitrogen was selected as the glovebox atmosphere for the Replacement Tritium Facility (RTF) at the Savannah River Site (SRS), a concern was raised as to the possibility of tritiated ammonia formation in the gloveboxes. Experimental data were produced to study the tritiated ammonia formation rate in a tritium and nitrogen mixture. A rate equation that closely simulates the experimental data was developed. This rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T 2 and N 2 to form NT 3 is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach radiochemical equilibrium dependent on the concentrations of the reactants. 4 refs., 6 figs., 1 tab

  1. Galaxy formation and evolution

    Mo, Houjun; White, Simon

    2010-01-01

    The rapidly expanding field of galaxy formation lies at the interface between astronomy, particle physics, and cosmology. Covering diverse topics from these disciplines, all of which are needed to understand how galaxies form and evolve, this book is ideal for researchers entering the field. Individual chapters explore the evolution of the Universe as a whole and its particle and radiation content; linear and nonlinear growth of cosmic structure; processes affecting the gaseous and dark matter components of galaxies and their stellar populations; the formation of spiral and elliptical galaxies; central supermassive black holes and the activity associated with them; galaxy interactions; and the intergalactic medium. Emphasizing both observational and theoretical aspects, this book provides a coherent introduction for astronomers, cosmologists, and astroparticle physicists to the broad range of science underlying the formation and evolution of galaxies.

  2. Observsational Planet Formation

    Dong, Ruobing; Zhu, Zhaohuan; Fung, Jeffrey

    2017-06-01

    Planets form in gaseous protoplanetary disks surrounding newborn stars. As such, the most direct way to learn how they form from observations, is to directly watch them forming in disks. In the past, this was very difficult due to a lack of observational capabilities; as such, planet formation was largely a subject of pure theoretical astrophysics. Now, thanks to a fleet of new instruments with unprecedented resolving power that have come online recently, we have just started to unveil features in resolve images of protoplanetary disks, such as gaps and spiral arms, that are most likely associated with embedded (unseen) planets. By comparing observations with theoretical models of planet-disk interactions, the masses and orbits of these still forming planets may be constrained. Such planets may help us to directly test various planet formation models. This marks the onset of a new field — observational planet formation. I will introduce the current status of this field.

  3. Forces in strategy formation

    Steensen, Elmer Fly; Sanchez, Ron

    2008-01-01

    This chapter proposes that organizational strategy formation should be characterized theoretically as a process that is subject to several interacting forces, rather than represented by separate discrete decisionmodels or theoretic perspectives, as is commonly done in the strategic management...... literature. Based on an extensive review of relevant theory and empirical work in strategic decision-making, organizational change theory, cognitive and social psychology, and strategy processes, seven kinds of ''forces'' - rational, imposed, teleological, learning, political, heuristic, and social...... - are identified as interacting in and having significant influence on the strategy formation process. It is further argued that by applying a holistic ''forces-view'' of the significant and interacting influences on strategy formation, we can better understand the dynamics and challenges in managing the process...

  4. Planetesimals and Planet Formation

    Chambers, John

    The first step in the standard model for planet formation is the growth of gravitationally bound bodies called ``planetesimals'' from dust grains in a protoplanetary disk. Currently, we do not know how planetesimals form, how long they take to form, or what their sizes and mechanical properties are. The goal of this proposal is to assess how these uncertainties affect subsequent stages of planetary growth and the kind of planetary systems that form. The work will address three particular questions: (i) Can the properties of small body populations in the modern Solar System constrain the properties of planetesimals? (ii) How do the properties of planetesimals affect the formation of giant planets? (iii) How does the presence of a water ice condensation front (the ``snow line'') in a disk affect planetesimal formation and the later stages of planetary growth? These questions will be examined with computer simulations of planet formation using new computer codes to be developed as part of the proposal. The first question will be addressed using a statistical model for planetesimal coagulation and fragmentation. This code will be merged with the proposer's Mercury N-body integrator code to model the dynamics of large protoplanets in order to address the second question. Finally, a self- consistent model of disk evolution and the radial transport of water ice and vapour will be added to examine the third question. A theoretical understanding of how planets form is one of the key goals of NASA and the Origins of Solar Systems programme. Researchers have carried out many studies designed to address this goal, but the questions of how planetesimals form and how their properties affect planet formation have received relatively little attention. The proposed work will help address these unsolved questions, and place other research in context by assessing the importance of planetesimal origins and properties for planet formation.

  5. Superclusters and galaxy formation

    Einasto, J.; Joeveer, M.; Saar, E.

    1979-01-01

    The spatial distribution of Galaxies and Galaxy congestions in the southern galactic hemisphere is studied. The rich galaxy congestions, containing many elliptic Galaxies and radiogalaxies, are linked with each other by chains of scanty congestions with moderate content of elliptic Galaxies and radiogalaxies. The flat formation, linking the density pikes and the intermediate chains, can reasonably be called supercongestion. In the central region of supercongestions there is a thin layer of Galaxies consisting of only spiral Galaxies. The neighbouring supercongestions touch each other, while the intersupercongestion space contains no Galaxy congestions and almost no Galaxies. It is shown that such a structure was, apparently, formed before the formation of Galaxies

  6. Formation of galaxies

    Szalay, A.S.

    1984-12-01

    The present theories of galaxy formation are reviewed. The relation between peculiar velocities and the correlation function of galaxies points to the possibility that galaxies do not form uniformly everywhere. Scale invariant properties of the cluster-cluster correlations are discussed. Comparing the correlation functions in a dimensionless way, galaxies appear to be stronger clustered, in contrast with the comparison of the dimensional amplitudes of the correlation functions. Theoretical implications of several observations as Lyman-α clouds, correlations of faint galaxies are discussed. None of the present theories of galaxy formation can account for all facts in a natural way. 29 references

  7. The formation of stars

    Stahler, Steven W

    2008-01-01

    This book is a comprehensive treatment of star formation, one of the most active fields of modern astronomy. The reader is guided through the subject in a logically compelling manner. Starting from a general description of stars and interstellar clouds, the authors delineate the earliest phases of stellar evolution. They discuss formation activity not only in the Milky Way, but also in other galaxies, both now and in the remote past. Theory and observation are thoroughly integrated, with the aid of numerous figures and images. In summary, this volume is an invaluable resource, both as a text f

  8. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC......Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...

  9. Barrier cell sheath formation

    Kesner, J.

    1980-04-01

    The solution for electrostatic potential within a simply modeled tandem mirror thermal barrier is seen to exhibit a sheath at each edge of the cell. The formation of the sheath requires ion collisionality and the analysis assmes that the collisional trapping rate into the barrier is considerably slower than the barrier pump rate

  10. Formation of topological defects

    Vachaspati, T.

    1991-01-01

    We consider the formation of point and line topological defects (monopoles and strings) from a general point of view by allowing the probability of formation of a defect to vary. To investigate the statistical properties of the defects at formation we give qualitative arguments that are independent of any particular model in which such defects occur. These arguments are substantiated by numerical results in the case of strings and for monopoles in two dimensions. We find that the network of strings at formation undergoes a transition at a certain critical density below which there are no infinite strings and the closed-string (loop) distribution is exponentially suppressed at large lengths. The results are contrasted with the results of statistical arguments applied to a box of strings in dynamical equilibrium. We argue that if point defects were to form with smaller probability, the distance between monopoles and antimonopoles would decrease while the monopole-to-monopole distance would increase. We find that monopoles are always paired with antimonopoles but the pairing becomes clean only when the number density of defects is small. A similar reasoning would also apply to other defects

  11. The formation of galaxies

    Gunn, J.E.

    1983-01-01

    The presently fashionable ideas for galaxy formation are reviewed briefly, and it is concluded that the standard isothermal heirarchy fits the available data best. A simple infall picture is presented which explains many of the observed properties of disk galaxies. (orig.)

  12. Reconsidering Formative Measurement

    Howell, Roy D.; Breivik, Einar; Wilcox, James B.

    2007-01-01

    The relationship between observable responses and the latent constructs they are purported to measure has received considerable attention recently, with particular focus on what has become known as formative measurement. This alternative to reflective measurement in the area of theory-testing research is examined in the context of the potential…

  13. Chlorination and chloramines formation

    Yee, Lim Fang; Mohd Pauzi Abdullah; Sadia Ata; Abbas Abdullah; Basar IShak; Khairul Nidzham

    2008-01-01

    Chlorination is the most important method of disinfection in Malaysia which aims at ensuring an acceptable and safe drinking water quality. The dosing of chlorine to surface water containing ammonia and nitrogen compounds may form chloramines in the treated water. During this reaction, inorganic and organic chloramines are formed. The recommended maximum acceptable concentration (MAC) for chloramines in drinking water is 3000 μg/L. The production of monochloramine, dichloramine and trichloramine is highly dependent upon pH, contact time and the chlorine to ammonia molar ratio. The purpose of this study is to examine the formation of chloramines that occur upon the chlorination during the treatment process. Chloramines were determined using the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method. The influences of ammonia, pH and chlorine dosage on the chloramines formation were also studied. This paper presents a modeling approach based on regression analysis which is designed to estimate the formation of chloramines. The correlation between the concentration of chloramines and the ammonia, pH and chlorine dosage was examined. In all cases, the quantity of chloramines formed depended linearly upon the amount of chlorine dosage. On the basis of this study it reveals that the concentration of chloramines is a function of chlorine dosage and the ammonia concentration to the chlorination process. PH seems to not significantly affect the formation of chloramines. (author)

  14. Temperature controlled 'void' formation

    Dasgupta, P.; Sharma, B.D.

    1975-01-01

    The nucleation and growth of voids in structural materials during high temperature deformation or irradiation is essentially dependent upon the existence of 'vacancy supersaturation'. The role of temperature dependent diffusion processes in 'void' formation under varying conditions, and the mechanical property changes associated with this microstructure are briefly reviewed. (author)

  15. Triggered star formation

    Palouš, Jan; Ehlerová, Soňa

    2002-01-01

    Roč. 12, - (2002), s. 35-36 ISSN 1405-2059 R&D Projects: GA AV ČR IAA3003705; GA AV ČR KSK1048102 Institutional research plan: CEZ:AV0Z1003909 Keywords : interstellar medium * star formation * HI shells Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. Syntactic Formats for Free

    Klin, Bartek; Sobocinski, Pawel

    2003-01-01

    A framework of Plotkin and Turi’s, originally aimed at providing an abstract notion of bi-simulation, is modified to cover other operational equivalences and preorders. Combined with bi-algebraic methods, it yields a technique for the derivation of syntactic formats for transition system specific...

  17. Formation of double layers

    Leung, P.; Wong, A.Y.; Quon, B.H.

    1981-01-01

    Experiments on both stationary and propagating double layers and a related analytical model are described. Stationary double layers were produced in a multiple plasma device, in which an electron drift current was present. An investigation of the plasma parameters for the stable double layer condition is described. The particle distribution in the stable double layer establishes a potential profile, which creates electron and ion beams that excite plasma instabilities. The measured characteristics of the instabilities are consistent with the existence of the double layer. Propagating double layers are formed when the initial electron drift current is large. Ths slopes of the transition region increase as they propagate. A physical model for the formation of a double layer in the experimental device is described. This model explains the formation of the low potential region on the basis of the space charge. This space charge is created by the electron drift current. The model also accounts for the role of ions in double layer formation and explains the formation of moving double layers. (Auth.)

  18. COMPETENCYTHE FORMATION FOR LIFE

    Milagros Mederos-Piñeiro

    2016-07-01

    Full Text Available The formation of life competences is the result of a quality education that prepares students to meet the challenges of a fast moving world where equality and equal opportunities should constitute premises of education; training them is a challenge teachers to assume new generations contribute actively to a better world. In Cuba are important research on the formation of communication competences and self-regulated learning in primary school. The paper shows the result of an investigation that provides a methodology for the formation of life competences in primary school education, used as an essential pathway research activity. The methodological approach of research has a quantitative approach and an explanatory scope to establish and make sense of understanding the causal relationship between the direction of research activity and training of life competences. Theoretical, empirical and mathematical-statistical, for characterizing the initial state, processing of results and analysis: research methods are used. The application of the methodology for the formation of life competences makes teachers lead the teaching-learning process with a research and transforming teaching concept, where the school is the protagonist of their learning and causes changes in their performances, which are evident in the formed competences related to effective and affective communication; the solution of problems related to life; the use of means in obtaining the knowledge and the expression of a behavior consistent with school and social demands. The effectiveness of the methodology confirms that there is a causal relationship between the direction of research activity by teachers and the formation of life competences in school.

  19. Morphologic evaluation of goat spermatozoa diluted and frozen in media based on powder coconut water (PCW-101 or TRIS, stained by eosin-nigrosin and bromophenol blue AVALIAÇÃO MORFOLÓGICA DE ESPERMATOZÓIDES CAPRINOS DILUÍDOS E CONGELADOS EM MEIO À BASE DE ÁGUA DE COCO EM PÓ (ACP-101 OU TRIS, CORADOS POR EOSINA-NIGROSINA E AZUL DE BROMOFENOL

    Arlindo Alencar de Araripe Moura

    2009-09-01

    Full Text Available

    This aims of the work were: to evaluate in vitro the goat semen frozen in diluents media based on powder coconut water (PCW-101 and TRIS and, compare the bromophenol blue stain efficiency with the eosin-nigrosin stain. The ejaculateds were divided and diluted into PCW-101 and TRIS, frozed and thawed after 30 days. Spermatic morphology was evaluated, through semen smears stained by eosin-nigrosin (EN and bromophenol blue (BB. The morphologic parameters evaluated were: normal spermatozoa (N, head alteration (HA, intermediary piece alteration (IPA, tail alteration (TA, proximal citoplasmic drop (PCD, distal citoplasmic drop (DCD, and detached head (DH. There wasn’t significant difference in the observation of N between media, staining and their interactions after 5 minutes of thermo resistance test. After 120, the N was significantly influenced by media, where the TRIS presented better results. The incubation period of 120 minutes at 37ºC affect the spermatic morphology, increasing the HA percentages. The media based on TRIS promoted better protection from the cryoinjuries on frozen goat spermatozoa. BB staining was efficient on the fresh and post-thaw goat semen evaluation.

    KEY WORDS: Bromophenol blue, goat, powder coconut water; TRIS, spermatozoa.

    Este trabalho teve como objetivos avaliar a morfologia de espermatozoides caprinos frescos e congelados em meios à base de água de coco em pó (ACP-101 e TRIS, bem como comparar a eficiência dos corantes azul de bromofenol (AB e eosina-nigrosina (EN. Cada ejaculado foi dividido, diluído em ACP-101 e TRIS, congelado e, após trinta dias, descongelado. Analisou-se a morfologia espermática por esfregaços corados por EN e AB. Os parâmetros morfológicos foram: espermatozoides normais (N, alterações de cabeça (AC, de peça intermediária (API, de flagelo (AF, gotas citoplasmáticas proximal (GCP e distal (GCD e cabeça destacada (CD. Não se verificou diferença de N entre

  20. Soroprevalência e fatores de risco para a língua azul em carneiros das mesorregiões do Sertão e da Borborema, semi-árido do Estado da Paraíba, Brasil Seroprevalence and risk factors for Bluetongue in rams of the Sertão and Borborema mesoregions, semi-arid of Paraíba state, Northeastern Brazil

    Francisco de Assis Leandro Alves

    2009-04-01

    Full Text Available Neste estudo foi determinada a prevalência de anticorpos contra o vírus da língua azul em carneiros das mesorregiões do Sertão e da Borborema, semi-árido do Estado da Paraíba, bem como foram identificados os fatores de risco associados à infecção. A amostragem foi delineada para a determinação da prevalência de propriedades positivas (focos e de animais soropositivos por mesorregião. Foi realizada uma seleção aleatória de unidades primárias, composta por 189 propriedades no Sertão e 100 propriedades na Borborema. Dentro das unidades primárias, foram amostrados todos os carneiros (unidades secundárias, resultando em 321 animais no Sertão e 185 na Borborema. Na ocasião da coleta, foi aplicado um questionário epidemiológico por propriedade. Para o diagnóstico sorológico, foi utilizada a prova de imunodifusão em gel de ágar (IDGA, com antígeno produzido na Escola de Veterinária da Universidade Federal de Minas Gerais. Uma propriedade foi considerada foco quando apresentou pelo menos um animal soropositivo. Na mesorregião do Sertão, as prevalências de focos e de animais soropositivos foram de 11,6% [7,8% - 17,1%] e 8,4% [5,7% - 12,3%], respectivamente. Na mesorregião da Borborema, a prevalência de focos foi de 0,0% [0,0% - 3,6%] e a prevalência de animais soropositivos foi de 0,0% [0,0% - 2,0%]. Os fatores de risco associados à língua azul foram a não realização de higiene das instalações (OR = 5,51 e a vermifugação dos animais duas a quatro vezes ao ano (OR = 4,44.The prevalence of antibodies against Bluetongue virus in rams of the Sertão and Borborema mesoregions, semi-arid of the Paraíba state, Northeastern Brazil, was determined, and risk factors for the infection were identified. The sampling was delineated for the determination of the prevalence of positive herds and seropositive animals for each mesoregion. Herds (primary units were randomly selected in the Sertão mesoregion (n = 189 and in the

  1. Medusae Fossae Formation

    2002-01-01

    (Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust

  2. The format of things

    Jørnø, Rasmus Leth

    this conception is identified as “the Format of Things.” The format is embedded in our everyday thinking. In relation to design,it is found in the name taken by the design community, that is human-computer interaction (HCI), and it is mirrored in the desktop metaphor, wherein information is conceived...... available. It consists of philosophical considerations on matters of relevance for the design of interfaces. It takes the position that the graphical user interfaces of computers (the Desktop Metaphor or Windows, Icons, Menus, Pointers [‘WIMP’]) that ordinarily come to mind for most people are cognates......The development of novel interfaces is one of the most important current design challenges for the intellectual, cultural and cognitive evolution of human imagination and knowledge work. Unfortunately, the thinking surrounding this design challenge is heavily mired in conceptions that harbor...

  3. Plasma formation in TBR

    Del Bosco, E.

    1981-01-01

    In this work are presented and discussed results of the formation and equilibrium of the plasma current in TBR, a small tokamak, designed and contructed at the Instituto de Fisica of Universidade de Sao Paulo. The measured breakdown curves for H 2 , A and He are compared with the predictions of a simple model with reasonable agreement. The influence of stray magnetic fields in the plasma formation is investigated and conditions are chosen to facilitate the breakdown. The time profile of loop voltage and plasma current for shots with plasma equilibrium are shown. A comparison is made between experimental results and analytical-numerical model for tokamaks discharges with ohmic heating. Reasonable agreement is obtained when Z, effective atomic number, is assumed as a parameter. (Author) [pt

  4. Formation of coronal cavities

    An, C.H.; Suess, S.T.; Tandberg-Hanssen, E.; Steinolfson, R.S.

    1986-01-01

    A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due to lack of stable magnetic support against gravity. The existence of a coronal cavity depends on the coronal magnetic field strength; with low strength, the plasma density is not high enough for condensation to occur. Furthermore, we suggest that prominence and cavity material is supplied from the chromospheric level. Whether a coronal cavity and a prominence coexist depends on the magnetic field configuration; a prominence requires stable magnetic support

  5. Understanding Alliance Formation Patterns

    2015-12-01

    military, transportation, and communications technologies, which caused every place in the world to be politically significant. Second, “divisions of power...test a similar claim about the association between distance and dyadic alliance formation. In their first model, in which they use the complete data...1885 to 1990] are positively related to dyadic trade levels, and that their non- defense-pact counterparts are not significantly related to trade in

  6. Alkali metal hydride formation

    1976-01-01

    The present invention relates to a method of producing alkali metal hydrides by absorbing hydrogen gas under pressure into a mixture of lower alkyl mono amines and alkali metal alkyl amides selected from sodium and potassium amides formed from said amines. The present invention also includes purification of a mixture of the amines and amides which contain impurities, such as is used as a catalytic exchange liquid in the enrichment of deuterium, involving the formation of the alkali metal hydride

  7. Formation of TRAPPIST-1

    Ormel, C. W.; Liu, B.; Schoonenberg, D.

    2017-09-01

    We present a model for the formation of the recently-discovered TRAPPIST-1 planetary system. In our scenario planets form in the interior regions, by accretion of mm to cm-size particles (pebbles) that drifted from the outer disk. This scenario has several advantages: it connects to the observation that disks are made up of pebbles, it is efficient, it explains why the TRAPPIST-1 planets are ˜Earth mass, and it provides a rationale for the system's architecture.

  8. THE ALLIANCE FORMATION PROCESS

    Whipple, Judith M.; Frankel, Robert

    1998-01-01

    While interest in developing strategic alliances within the food system continues to increase, there remains considerable risk when firms adopt such a cooperative strategy. The risk is due in part to the lack of concrete guidelines that illustrate the steps or stages of alliance development and the important strategic and operational decisions required at each stage. The existence of such guidelines would facilitate alliance formation and enable managers and researchers to better understand a...

  9. Complexity and formative experiences

    Roque Strieder

    2017-12-01

    Full Text Available The contemporaneity is characterized by instability and diversity calling into question certainties and truths proposed in modernity. We recognize that the reality of things and phenomena become effective as a set of events, interactions, retroactions and chances. This different frame extends the need for revision of the epistemological foundations that sustain educational practices and give them sense. The complex thinking is an alternative option for acting as a counterpoint to classical science and its reductionist logic and knowledge compartmentalization, as well as to answer to contemporary epistemological and educational challenges. It aims to associate different areas and forms of knowledge, without, however merge them, distinguishing without separating the several disciplines and instances of the realities. This study, in theoretical references, highlights the relevance of complex approaches to support formative experiences because also able to produce complexities in reflections about educational issues. We conclude that formative possibilities from complexity potentialize the resignification of human’s conception and the understanding of its singularity in interdependence; The understanding that pedagogical and educational activities is a constant interrogation about the possibilities of knowing the knowledge and reframe learning, far beyond knowing its functions and utilitarian purposes; and, as a formative possibility, places us on the trail of responsibility, not as something eventual, but present and indicative of freedom to choose to stay or go beyond.

  10. Terrestrial planet formation.

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  11. Fracturing of subterranean formations

    Kiel, O.M.; Kidwell, A.L.

    1968-03-19

    This method of propping fractured formations results in high conductivities. In the method, certain naturally occurring crystals are used as propping agents. Suitable crystals include garnet, corundum, zircon, rutile, high-temperature quartz, and other minerals which have Moh's hardness values of about 6 or greater and weather out as individual crystals of about 40 mesh or larger. These are said to result in permeabilities significantly higher than those obtained with ordinary quartz sand, metallic shot, glass beads, plastic particles, walnut hulls, or similar materials. (10 claims)

  12. Situated Formative Feedback

    Lukassen, Niels Bech; Wahl, Christian; Sorensen, Elsebeth Korsgaard

    refer to this type of feedback as, Situated Formative Feedback (SFF). As a basis for exploring, identifying and discussing relevant aspects of SFF the paper analyses qualitative data from a Moodle dialogue. Data are embedded in the qualitative analytic program Nvivo and are analysed with a system...... theoretical textual analysis method. Asynchronous written dialogue from an online master’s course at Aalborg University forms the empirical basis of the study. The findings suggests in general that students play an essential role in SFF and that students and educators are equal in the COP, but holds different...

  13. Superclusters and galaxy formation

    Einasto, J; Joeveer, M; Saar, E [Tartu Astrophysical Observatory, Toravere, Estonia (USSR)

    1980-01-03

    A study of the structure of superclusters in the Southern galactic hemisphere using Zwicky clusters as principal tracers of the large-scale structure of the Universe is reported. The data presented suggest that the formation of galaxies was a two stage process involving larger spatial dimensions than earlier workers have postulated. In the first stage proto-superclusters and big holes had to form from the non-dissipative dark matter while in the second hot gas, by cooling and settling down into the potential wells caused by dark matter, will form galaxies and clusters of galaxies.

  14. Urbanization and Slum Formation

    Phua, Kai Hong

    2007-01-01

    The formation of slums need not be inevitable with rapid urbanization. Such an argument appears to be contradicted by evidence of large slum populations in a large number of developing countries and particularly in rapidly urbanizing regions like Asia. The evidence discussed suggests that city authorities faced with rapid urban development lack the capacity to cope with the diverse demands for infrastructural provision to meet economic and social needs. Not only are strategic planning and intervention major issues in agenda to manage rapid urbanization, but city governments are not effectively linking the economic development trajectory to implications for urban growth and, hence, housing needs. In the following discussion, a case study is presented in support of the argument that city governments have to first recognize and then act to establish the link that is crucial between economic development, urban growth, and housing. This is the agendum that has been largely neglected by city and national governments that have been narrowly focused on economic growth with the consequent proliferation of slum formation as a housing solution. PMID:17387618

  15. Formation of planetary systems

    Brahic, A.

    1982-01-01

    It seemed appropriate to devote the 1980 School to the origin of the solar system and more particularly to the formation of planetary systems (dynamic accretion processes, small bodies, planetary rings, etc...) and to the physics and chemistry of planetary interiors, surface and atmospheres (physical and chemical constraints associated with their formation). This Summer School enabled both young researchers and hard-nosed scientists, gathered together in idyllic surroundings, to hold numerous discussions, to lay the foundations for future cooperation, to acquire an excellent basic understanding, and to make many useful contacts. This volume reflects the lectures and presentations that were delivered in this Summer School setting. It is aimed at both advanced students and research workers wishing to specialize in planetology. Every effort has been made to give an overview of the basic knowledge required in order to gain a better understanding of the origin of the solar system. Each article has been revised by one or two referees whom I would like to thank for their assistance. Between the end of the School in August 1980 and the publication of this volume in 1982, the Voyager probes have returned a wealth of useful information. Some preliminary results have been included for completeness

  16. A Mesoproterozoic iron formation

    Canfield, Donald E.; Zhang, Shuichang; Wang, Huajian; Wang, Xiaomei; Zhao, Wenzhi; Su, Jin; Bjerrum, Christian J.; Haxen, Emma R.; Hammarlund, Emma U.

    2018-04-01

    We describe a 1,400 million-year old (Ma) iron formation (IF) from the Xiamaling Formation of the North China Craton. We estimate this IF to have contained at least 520 gigatons of authigenic Fe, comparable in size to many IFs of the Paleoproterozoic Era (2,500–1,600 Ma). Therefore, substantial IFs formed in the time window between 1,800 and 800 Ma, where they are generally believed to have been absent. The Xiamaling IF is of exceptionally low thermal maturity, allowing the preservation of organic biomarkers and an unprecedented view of iron-cycle dynamics during IF emplacement. We identify tetramethyl aryl isoprenoid (TMAI) biomarkers linked to anoxygenic photosynthetic bacteria and thus phototrophic Fe oxidation. Although we cannot rule out other pathways of Fe oxidation, iron and organic matter likely deposited to the sediment in a ratio similar to that expected for anoxygenic photosynthesis. Fe reduction was likely a dominant and efficient pathway of organic matter mineralization, as indicated by organic matter maturation by Rock Eval pyrolysis combined with carbon isotope analyses: Indeed, Fe reduction was seemingly as efficient as oxic respiration. Overall, this Mesoproterozoic-aged IF shows many similarities to Archean-aged (>2,500 Ma) banded IFs (BIFs), but with an exceptional state of preservation, allowing an unprecedented exploration of Fe-cycle dynamics in IF deposition.

  17. Endocytosis and Enamel Formation

    Cong-Dat Pham

    2017-07-01

    Full Text Available Enamel formation requires consecutive stages of development to achieve its characteristic extreme mineral hardness. Mineralization depends on the initial presence then removal of degraded enamel proteins from the matrix via endocytosis. The ameloblast membrane resides at the interface between matrix and cell. Enamel formation is controlled by ameloblasts that produce enamel in stages to build the enamel layer (secretory stage and to reach final mineralization (maturation stage. Each stage has specific functional requirements for the ameloblasts. Ameloblasts adopt different cell morphologies during each stage. Protein trafficking including the secretion and endocytosis of enamel proteins is a fundamental task in ameloblasts. The sites of internalization of enamel proteins on the ameloblast membrane are specific for every stage. In this review, an overview of endocytosis and trafficking of vesicles in ameloblasts is presented. The pathways for internalization and routing of vesicles are described. Endocytosis is proposed as a mechanism to remove debris of degraded enamel protein and to obtain feedback from the matrix on the status of the maturing enamel.

  18. Star Formation in Irregular Galaxies.

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

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

  19. Standard exercise report format (SERF)

    Anon.

    1995-01-01

    This talk summarizes the reasons for the development of draft SERF the Standard Exercise Report Format used for reporting the results of emergency preparedness exercises, and gives a summary of the format and rational behind it

  20. Restoring formation after leaching process

    Barrett, R.B.

    1983-01-01

    A method of restoring a formation which had uranium and other mineral values extracted by an alkaline lixiviant comprises introducing a source of phosphate in an amount sufficient to lower the level of soluble uranium compounds below that previously existing in the formation by the formation of insoluble uranium phosphate compounds

  1. Formative Research in Educational Media.

    Hodapp, Timothy

    This paper distinguishes between basic research, applied research, and evaluation. Evaluation is broken down into two types: summative and formative. The limitations of formative research are presented, followed by a discussion of the value of the formative researcher participating in the product planning process. The types of data which formative…

  2. Designing for informed group formation

    Nicolajsen, Hanne Westh; Juel Jacobsen, Alice; Riis, Marianne

    2012-01-01

    A new design ―project preparation‖ preparing for the group formation in problem based project work is proposed and investigated. The main problem is to overcome group formation based on existing relations. The hypothesis is that theme development and group formation are somewhat counterproductive...

  3. Determinants for gallstone formation

    Shabanzadeh, Daniel Monsted; Sorensen, Lars Tue; Jørgensen, Torben

    2016-01-01

    . Gallstone incidence was assessed through repeated ultrasound examinations. Body mass index (BMI), blood pressure, self-rated health, lifestyle variables, blood lipids, and use of female sex hormones were measured at the baseline examination. Statistical analyses included logistic regression. Based...... re-examination were followed-up completely (mean 11.6 years, N = 2848). The overall cumulative incidence of gallstones was 0.60% per year. Independent positive determinants for incident gallstones were age, female sex, non-high density lipoprotein (non-HDL) cholesterol, and gallbladder polyps...... associations were found for blood pressure, smoking, alcohol consumption, HDL cholesterol, or triglycerides in meta-analyses. Conclusions: Age, female sex, BMI, non-HDL cholesterol, and polyps are independent determinants for gallstone formation. Incident gallstones and the metabolic syndrome share common risk...

  4. Standardizing exchange formats

    Lemmel, H.D.; Schmidt, J.J.

    1992-01-01

    An international network of co-operating data centres is described who maintain identical data bases which are simultaneously updated by an agreed data exchange procedure. The agreement covers ''data exchange formats'' which are compatible to the centres' internal data storage and retrieval systems which remain different, optimized at each centre to the available computer facilities and to the needs of the data users. Essential condition for the data exchange is an agreement on common procedures for the data exchange is an agreement on common procedures for the data compilation, including critical data analysis and validation. The systems described (''EXFOR'', ''ENDF'', ''CINDA'') are used for ''nuclear reaction data'', but the principles used for data compilation and exchange should be valid also for other data types. (author). 24 refs, 4 figs

  5. Recipes for planet formation

    Meyer, Michael R.

    2009-11-01

    Anyone who has ever used baking soda instead of baking powder when trying to make a cake knows a simple truth: ingredients matter. The same is true for planet formation. Planets are made from the materials that coalesce in a rotating disk around young stars - essentially the "leftovers" from when the stars themselves formed through the gravitational collapse of rotating clouds of gas and dust. The planet-making disk should therefore initially have the same gas-to-dust ratio as the interstellar medium: about 100 to 1, by mass. Similarly, it seems logical that the elemental composition of the disk should match that of the star, reflecting the initial conditions at that particular spot in the galaxy.

  6. Formation of Service Ecosystems

    Jonas, Julia M.; Sörhammar, David; Satzger, Gerhard

    – i.e. the “birth phase” (Moore, 2009) of a service ecosystem. This paper, therefore, aims to explore how the somewhat “magic” processes of service ecosystem formation that are being taken for granted actually occur. Methodology/Approach: Building on a review of core elements in the definitions...... for Harvard students) or value proposition (share messages, photos, videos, etc. with friends). Processes of configuring actors, resources, and value propositions are influenced by the structural embeddedness of the service ecosystem (e.g., regional infrastructure, existing networks of actors, or resource...... availability) as well as guided by the actors’ own and shared institutions (e.g., rules, norms,and beliefs).We contextualize each starting point with illustrative cases and analyze the service ecosystem configuration process: “Axoon/Trumpf” (initiated by resources), “JOSEPHS – the service manufactory...

  7. Symbol Formation Reconsidered

    Wagoner, Brady

    2013-01-01

    them vis-à-vis other research at Clark and in American psychology more generally. The second two articles analyse Werner and Kaplan’s notions of ‘distancing’ and ‘physiognomic metaphor’, showing their roots in naturphilosophie and comparing them with contemporary theories. The last four articles apply......Werner and Kaplan’s Symbol formation was published 50 years ago but its insights have yet to be adequately explored by psychology and other social sciences. This special issue aims to revisit this seminal work in search of concepts to work on key issues facing us today. This introductory article...... begins with a brief outline and contextualization of the book as well as of the articles that this special issue comprises. The first two articles were written by contributors who were part of the Werner era at Clark University. They explore the key concepts of the organismic and development, and situate...

  8. Formation of small sparks

    Barreto, E.; Jurenka, H.; Reynolds, S.I.

    1977-01-01

    The formation of a small incendiary spark at atmospheric pressure is identified with the transition from a weakly to a strongly ionized plasma. It is shown that initial gaseous ionization produced by avalanches and/or streamers always creates a high-temperature ideal electron gas that can shield the applied voltage difference and reduce ionization in the volume of the gas. The electron gas is collision dominated but able to maintain its high temperature, for times long compared to discharge events, through long-range Coulomb forces. In fact, electrons in the weakly ionized plasma constitute a collisionless independent fluid with a thermodynamic state that can be affected directly by field or density changes. Accordingly, with metal electrodes, cathode spot emission is always associated with the transition to a strongly ionized plasma. Neutral heating can be accomplished in two different ways. Effective dispersal of the electrons from the cathode leads to electron heating dominated by diffusion effects. Conversely, a fast rate of emission or rapid field changes can produce nonlinear wave propagation. It is shown that solitary waves are possible, and it is suggested that some spark transitions are associated with shock waves in the collisionless electron gas. In either the diffuse or nonlinear regime, neutral gas heating is controlled by collisions of ions with isotropic thermal electrons. This interaction is always subsequent to changes in state of the electron gas population. The basic results obtained should apply to all sparks

  9. Large Format Radiographic Imaging

    Rohrer, J. S.; Stewart, Lacey; Wilke, M. D.; King, N. S.; Baker A, S.; Lewis, Wilfred

    1999-01-01

    Radiographic imaging continues to be a key diagnostic in many areas at Los Alamos National Laboratory (LANL). Radiographic recording systems have taken on many form, from high repetition-rate, gated systems to film recording and storage phosphors. Some systems are designed for synchronization to an accelerator while others may be single shot or may record a frame sequence in a dynamic radiography experiment. While film recording remains a reliable standby in the radiographic community, there is growing interest in investigating electronic recording for many applications. The advantages of real time access to remote data acquisition are highly attractive. Cooled CCD camera systems are capable of providing greater sensitivity with improved signal-to-noise ratio. This paper begins with a review of performance characteristics of the Bechtel Nevada large format imaging system, a gated system capable of viewing scintillators up to 300 mm in diameter. We then examine configuration alternatives in lens coupled and fiber optically coupled electro-optical recording systems. Areas of investigation include tradeoffs between fiber optic and lens coupling, methods of image magnification, and spectral matching from scintillator to CCD camera. Key performance features discussed include field of view, resolution, sensitivity, dynamic range, and system noise characteristics

  10. What Determines Star Formation Rates?

    Evans, Neal John

    2017-06-01

    The relations between star formation and gas have received renewed attention. We combine studies on scales ranging from local (within 0.5 kpc) to distant galaxies to assess what factors contribute to star formation. These include studies of star forming regions in the Milky Way, the LMC, nearby galaxies with spatially resolved star formation, and integrated galaxy studies. We test whether total molecular gas or dense gas provides the best predictor of star formation rate. The star formation ``efficiency," defined as star formation rate divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all the molecular gas. We suggest ways to further develop the concept of "dense gas" to incorporate other factors, such as turbulence.

  11. Designing for informed group formation

    Nicolajsen, Hanne Westh; Juel Jacobsen, Alice; Riis, Marianne

    2012-01-01

    A new design ―project preparation‖ preparing for the group formation in problem based project work is proposed and investigated. The main problem is to overcome group formation based on existing relations. The hypothesis is that theme development and group formation are somewhat counterproductive....... Following research based design methodology an experiment separating the two was initiated.This was to provide for more openness and creativity in contrast to a design in which existing relations seem predominant....

  12. Light meromyosin paracrystal formation.

    Chowrashi, P K; Pepe, F A

    1977-07-01

    STUDIES OF PARACRYSTAL FORMATION BY COLUMN PURIFIED LIGHT MEROMYOSIN (LMM) PREPARED IN A VARIETY OF WAYS LED TO THE FOLLOWING CONCLUSIONS: (a) different portions of the myosin rod may be coded for different stagger relationships. This was concluded from observations that paracrystals with different axial repeat periodicities could be obtained either with LMM framents of different lengths prepared with the same enzyme, or with LMM fragments of identical lengths but prepared with different enzymes. (b) Paracrystals with a 14-nm axial repeat periodicity are most likely formed by the aggregation of sheets with a 44-nm axial repeat within the sheets which are staggered by 14 nm. All of the axial repeat patterns expected from one sheet or aggregates of more than one sheet, on this basis, were observed in the same electron micrograph. (c) C-protein binding probably occurs preferentially to LMM molecules related in some specific way. This was concluded from the observation that the same axial repeat pattern was obtained in paracrystals formed from different LMM preparations in the presence of C-protein, regardless of differences in the axial repeat obtained in the absence of C-protein. (d) Nucleic acid is responsible for the 43-nm axial repeat patterns observed in paracrystals formed by the ethanol-resistant fraction of LMM. In the absence of nuclei acid, paracrystals with a 14nm axial repeat are obtained. (e) The 43-nm axial repeat pattern observed with the ethanol-resistant fraction of LMM is different for LMM preparations obtained by trypsin and papain digestions.

  13. Pattern formation during electropolishing

    Yuzhakov, V.V.; Chang, H.; Miller, A.E.

    1997-01-01

    Using atomic force microscopy, we find that the surface morphology of a dissolving aluminum anode in a commercial electropolishing electrolyte can exhibit both highly regular and randomly packed stripe and hexagonal patterns with amplitudes of about 5 nm and wavelengths of 100 nm. The driving instability of this pattern formation phenomenon is proposed to be the preferential adsorption of polar or polarizable organic molecules on surface ridges where the contorted double layer produces a higher electric potential gradient. The enhanced relative coverage shields the anode and induces a smaller dissolution rate at the ridges. The instability is balanced by surface diffusion of the adsorbate to yield a length scale of 4π(D s /k d ) 1/2 , where D s is the surface diffusivity and k d is the desorption coefficient of the adsorbate, which correlates well with the measured wavelength. A long-wavelength expansion of the double-layer field yields an interface evolution equation that reproduces all of the observed patterns. In particular, bifurcation analysis and numerical simulation yield a single voltage-dependent dimensionless parameter ξ that measures a balance between smoothing of adsorbate concentration by electric-field-dependent surface diffusion and fluctuation due to interfacial curvature and stretching. Randomly oriented stripes are favored at large ξ (low voltage), while random hills dominate at small ξ (high voltage) with perfectly periodic stripes and hexagonal hill patterns within a small window near ξ=1. These predictions are in qualitative and quantitative agreement with our measurements. copyright 1997 The American Physical Society

  14. Formative assessment : Enriching teaching and learning with formative assesment

    van Diggelen, M.R.; Morgan, C.M.; Funk, M.; Bruns, M.

    2016-01-01

    Formative assessment is a valuable aspect in teaching and learning, and is proven to be an e ective learning method. There is evidence that adding formative assessment to your teaching increases students’ learning results (Black and William, 1998), but in practice many of the possibilities are left

  15. Formation of interstellar anions

    Senent, Maria Luisa

    2012-05-01

    Formation of interstellar anions: M.L. Senent. The recent detection of negative charged species in the ISM1 has instigated enthusiasm for anions in the astrophysical community2. Many of these species are new and entail characterization. How they are formed in astrophysical sources is a question of major relevance. The anion presence in ISM was first predicted theoretically on the basis of electron affinities and on the negative linear chain molecular stabilities. Although very early, they were considered in astrochemical models3-4, their discovery is so recent because their abundances seem to be relatively low. These have to be understood in terms of molecular stabilities, reaction probabilities and radiative and collisional excitations. Then, we present our theoretical work on even carbon chains type Cn and CnH (n=2,4,6) focused to the understanding of anion abundances. We use highly correlated ab initio methods. We performed spectroscopic studies of various isomers that can play important roles as intermediates5-8. In previous papers9-10, we compared C2H and C2H- collisional rates responsible for observed line intensities. Actually, we study hydrogen attachment (Cn +H → CnH and Cn- +H → CnH-) and associative detachment processes (Cn- +H → CnH +e-) for 2, 4 and 6 carbon atom chains11. [1] M.C.McCarthy, C.A.Gottlieb, H.Gupta, P.Thaddeus, Astrophys.J, 652, L141 (2006) [2] V.M.Bierbaum, J.Cernicharo, R.Bachiller, eds., 2011, pp 383-389. [3] A. Dalgarno, R.A. Mc Cray, Astrophys.J,, 181, 95 (1973) [4] E. Herbst E., Nature, 289, 656 (1981); [5] H.Massó, M.L.Senent, P.Rosmus, M.Hochlaf, J.Chem.Phys., 124, 234304 (2006) [6] M.L.Senent, M.Hochlaf, Astrophys. J. , 708, 1452(2010) [7] H.Massó, M.L.Senent, J.Phys.Chem.A, 113, 12404 (2009) [8] D. Hammoutene, M.Hochlaf, M.L.Senent, submitted. [9] A. Spielfiedel, N. Feautrier, F. Najar, D. ben Abdallah, F. Dayou, M.L. Senent, F. Lique, Mon.Not.R.Astron.Soc., 421, 1891 (2012) [10] F.Dumouchel, A, Spielfieldel , M

  16. Satellite formation flying relative dynamics, formation design, fuel optimal maneuvers and formation maintenance

    Wang, Danwei; Poh, Eng Kee

    2017-01-01

    This book systematically describes the concepts and principles for multi-satellite relative motion, passive and near passive formation designs, trajectory planning and control for fuel optimal formation maneuvers, and formation flying maintenance control design. As such, it provides a sound foundation for researchers and engineers in this field to develop further theories and pursue their implementations. Though satellite formation flying is widely considered to be a major advance in space technology, there are few systematic treatments of the topic in the literature. Addressing that gap, the book offers a valuable resource for academics, researchers, postgraduate students and practitioners in the field of satellite science and engineering.

  17. Portable File Format (PFF) specifications

    Dolan, Daniel H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    Created at Sandia National Laboratories, the Portable File Format (PFF) allows binary data transfer across computer platforms. Although this capability is supported by many other formats, PFF files are still in use at Sandia, particularly in pulsed power research. This report provides detailed PFF specifications for accessing data without relying on legacy code.

  18. Professional Development through Formative Evaluation

    Nsibande, Rejoice; Garraway, James

    2011-01-01

    Formative evaluation and its associated methodology of reflection on practice are used extensively in academic staff development. In reflecting on formative evaluation processes in both more traditional and newer programmes conducted at a university of technology, a number of variables reported in the literature were observed to have influenced…

  19. Star formation in the multiverse

    Bousso, Raphael; Leichenauer, Stefan

    2009-01-01

    We develop a simple semianalytic model of the star formation rate as a function of time. We estimate the star formation rate for a wide range of values of the cosmological constant, spatial curvature, and primordial density contrast. Our model can predict such parameters in the multiverse, if the underlying theory landscape and the cosmological measure are known.

  20. A format for phylogenetic placements.

    Frederick A Matsen

    Full Text Available We have developed a unified format for phylogenetic placements, that is, mappings of environmental sequence data (e.g., short reads into a phylogenetic tree. We are motivated to do so by the growing number of tools for computing and post-processing phylogenetic placements, and the lack of an established standard for storing them. The format is lightweight, versatile, extensible, and is based on the JSON format, which can be parsed by most modern programming languages. Our format is already implemented in several tools for computing and post-processing parsimony- and likelihood-based phylogenetic placements and has worked well in practice. We believe that establishing a standard format for analyzing read placements at this early stage will lead to a more efficient development of powerful and portable post-analysis tools for the growing applications of phylogenetic placement.

  1. Uranium logging in earth formations

    Givens, W.W.

    1979-01-01

    A technique is provided for assaying the formations surrounding a borehole for uranium. A borehole logging tool cyclically irradiates the formations with neutrons and responds to neutron fluxes produced during the period of time that prompt neutrons are being produced by the neutron fission of uranium in the formations. A borehole calibration tool employs a steady-state (continuous output) neutron source, firstly, to produce a response to neutron fluxes in models having known concentrations of uranium and, secondly, to to produce a response to neutron fluxes in the formations surrounding the borehole. The neutron flux responses of the borehole calibration tool in both the model and the formations surrounding the borehole are utilized to correct the neutron flux response of the borehole logging tool for the effects of epithermal/thermal neutron moderation, scattering, and absorption within the borehole itself

  2. Geological factors of deposit formation

    Grushevoj, G.V.

    1980-01-01

    Geologic factors of hydrogenic uranium deposit formation are considered. Structural, formation and lithological-facies factors of deposit formation, connected with zones of stratal oxidation, are characterized. Peculiarities of deposit localization, connected with orogenic structures of Mesozoic and lenozoic age, are described. It is noted that deposits of anagenous group are widely spread in Paleozoic formations, infiltration uranium deposits are localized mainly in Cenozoic sediments, while uranium mineralization both anagenous and infiltration groups are widely developed in Mesozoic sediments. Anagenous deposits were formed in non-oxygen situation, their age varies from 200 to 55 mln years. Infiltration deposit formation is determined by asymmetric oxidation zonation, their age varies from 10 - 40 mln years to dozens of thousand years [ru

  3. Synthesis and characterization of CeO{sub 2} - TiO{sub 2} system for use in heterogeneous photocatalysis in photodegradation of methylene blue dye; Sintese e caracterizacao do sistema CeO{sub 2} - TiO{sub 2} para aplicacao em fotocatalise heterogenea na fotodegradacao do corante azul de metileno

    Bragatto, Julia

    2016-07-01

    This study has as its goal the synthesis of a mixed oxide system type CeO{sub 2} - TiO{sub 2}, through the polymeric precursor method, to be used in heterogeneous photocatalysis. The synthesized materials were characterized by Thermogravimetry (TG), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA) and X-Ray Diffraction (XRD). The results of the thermal analysis showed in what temperature ranges certain events occur such as the formation of cerium oxide between 600 and 800 ° C, which refers to the crystallization of the material. Regarding the formation of titanium oxide, events between 600 and 800 ° C are perceived, which suggests the transformation of anatase to rutile phase. The XRD analysis showed no occurrence of the same phase for all materials, meaning that there is a variation in the formation of phases according to concentration of precursor for each sample. Noteworthy are the formation of CeO{sub 2} for Ce75-Ti25 and Ce50-Ti50 concentrations, with cubic crystal structure of the fluorite type. In Ce75-Ti25 and Ce25-Ti75 it is present the TiO{sub 2} in the anatase and rutile phase, with crystal structure of the tetragonal and tetrahedron type, respectively, as well as the formation of CeTi{sub 2}O{sub 6} in Ce50-Ti50 and Ce25-Ti75, with structure monoclinic. From these analyses, it is possible to see which samples, and in which temperatures of calcination the material has increased crystallinity, making the choice for their application in heterogeneous photocatalysis, aiming the degradation of methylene blue dye. Among the tested materials for methylene blue, the sample that stood out was the Ce50-Ti50, with calcination temperature of 800 °C, with values close to 50% degradation, because it was the sample that showed higher dye adsorption capacity, which is the step that precedes photodegradation. (author)

  4. Process for fracturing underground formations

    Kiel, O M

    1974-01-25

    This invention concerns a process for fracturing underground formations and has as one object the mixing of viscous compositions. Through a borehole, a fluid is injected into the formation. This fluid contains a complex prepared by the reaction of an aliphatic quaternary ammonium compound with a water-soluble compound chosen from monosaccharides, disaccharides, trisaccharides, polysaccharides, and synthetic hydroxylated polymers with long chains. These complexes are formed at temperatures between 20/sup 0/ and 205/sup 0/C. The process also includes production of formation fluid into the borehole.

  5. Free-format RPG IV

    Martin, Jim

    2013-01-01

    This how-to guide offers a concise and thorough introduction to the increased productivity, better readability, and easier program maintenance that comes with the free-format style of programming in RPG IV. Although free-format information is available in IBM manuals, it is not separated from everything else, thereby requiring hours of tedious research to track down the information needed. This book provides everything one needs to know to write RPG IV in the free-format style, and author Jim Martin not only teaches rules and syntax but also explains how this new style of coding has the pot

  6. AGN feedback in galaxy formation

    Antonuccio-Delogu, Vincenzo

    2010-01-01

    During the past decade, convincing evidence has been accumulated concerning the effect of active galactic nuclei (AGN) activity on the internal and external environment of their host galaxies. Featuring contributions from well-respected researchers in the field, and bringing together work by specialists in both galaxy formation and AGN, this volume addresses a number of key questions about AGN feedback in the context of galaxy formation. The topics covered include downsizing and star-formation time scales in massive elliptical galaxies, the connection between the epochs of supermassive black h

  7. DNA methylation and memory formation.

    Day, Jeremy J; Sweatt, J David

    2010-11-01

    Memory formation and storage require long-lasting changes in memory-related neuronal circuits. Recent evidence indicates that DNA methylation may serve as a contributing mechanism in memory formation and storage. These emerging findings suggest a role for an epigenetic mechanism in learning and long-term memory maintenance and raise apparent conundrums and questions. For example, it is unclear how DNA methylation might be reversed during the formation of a memory, how changes in DNA methylation alter neuronal function to promote memory formation, and how DNA methylation patterns differ between neuronal structures to enable both consolidation and storage of memories. Here we evaluate the existing evidence supporting a role for DNA methylation in memory, discuss how DNA methylation may affect genetic and neuronal function to contribute to behavior, propose several future directions for the emerging subfield of neuroepigenetics, and begin to address some of the broader implications of this work.

  8. Robust Decentralized Formation Flight Control

    Zhao Weihua

    2011-01-01

    Full Text Available Motivated by the idea of multiplexed model predictive control (MMPC, this paper introduces a new framework for unmanned aerial vehicles (UAVs formation flight and coordination. Formulated using MMPC approach, the whole centralized formation flight system is considered as a linear periodic system with control inputs of each UAV subsystem as its periodic inputs. Divided into decentralized subsystems, the whole formation flight system is guaranteed stable if proper terminal cost and terminal constraints are added to each decentralized MPC formulation of the UAV subsystem. The decentralized robust MPC formulation for each UAV subsystem with bounded input disturbances and model uncertainties is also presented. Furthermore, an obstacle avoidance control scheme for any shape and size of obstacles, including the nonapriorily known ones, is integrated under the unified MPC framework. The results from simulations demonstrate that the proposed framework can successfully achieve robust collision-free formation flights.

  9. The multifaceted planetesimal formation process

    Johansen, Anders; Blum, Jürgen; Tanaka, Hidekazu

    2013-01-01

    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Left-over planetesimals in the form of asteroids, trans...... for planetesimal formation where particle growth starts unaided by self-gravity but later proceeds inside gravitationally collapsing pebble clumps to form planetesimals with a wide range of sizes....

  10. Chain formation of metal atoms

    Bahn, Sune Rastad; Jacobsen, Karsten Wedel

    2001-01-01

    The possibility of formation of single-atomic chains by manipulation of nanocontacts is studied for a selection of metals (Ni, Pd, Pt, Cu, Ag, Au). Molecular dynamics simulations show that the tendency for chain formation is strongest for Au and Pt. Density functional theory calculations indicate...... that the metals which form chains exhibit pronounced many-atom interactions with strong bonding in low coordinated systems....

  11. Cosmic strings and galaxy formation

    Bertschinger, Edmund

    1989-01-01

    The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

  12. An Adaptable Seismic Data Format

    Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; de Andrade, Elliott Sales; Podhorszki, Norbert; Bozdağ, Ebru; Tromp, Jeroen

    2016-11-01

    We present ASDF, the Adaptable Seismic Data Format, a modern and practical data format for all branches of seismology and beyond. The growing volume of freely available data coupled with ever expanding computational power opens avenues to tackle larger and more complex problems. Current bottlenecks include inefficient resource usage and insufficient data organization. Properly scaling a problem requires the resolution of both these challenges, and existing data formats are no longer up to the task. ASDF stores any number of synthetic, processed or unaltered waveforms in a single file. A key improvement compared to existing formats is the inclusion of comprehensive meta information, such as event or station information, in the same file. Additionally, it is also usable for any non-waveform data, for example, cross-correlations, adjoint sources or receiver functions. Last but not least, full provenance information can be stored alongside each item of data, thereby enhancing reproducibility and accountability. Any data set in our proposed format is self-describing and can be readily exchanged with others, facilitating collaboration. The utilization of the HDF5 container format grants efficient and parallel I/O operations, integrated compression algorithms and check sums to guard against data corruption. To not reinvent the wheel and to build upon past developments, we use existing standards like QuakeML, StationXML, W3C PROV and HDF5 wherever feasible. Usability and tool support are crucial for any new format to gain acceptance. We developed mature C/Fortran and Python based APIs coupling ASDF to the widely used SPECFEM3D_GLOBE and ObsPy toolkits.

  13. Review of nutrition labeling formats.

    Geiger, C J; Wyse, B W; Parent, C R; Hansen, R G

    1991-07-01

    This article examines nutrition labeling history as well as the findings of nine research studies of nutrition labeling formats. Nutrition labeling regulations were announced in 1973 and have been periodically amended since then. In response to requests from consumers and health care professionals for revision of the labeling system, the Food and Drug Administration initiated a three-phase plan for reform of nutrition labeling in 1990. President Bush signed the Nutrition Labeling and Education Act in November 1990. Literature analysis revealed that only nine studies with an experimental design have focused on nutrition labeling since 1971. Four were conducted before 1975, which was the year that nutrition labeling was officially implemented, two were conducted in 1980, and three were conducted after 1986. Only two of the nine studies supported the traditional label format mandated by the Code of Federal Regulations, and one study partially supported it. Four of the nine studies that evaluated graphic presentations of nutrition information found that consumer comprehension of nutrition information was improved with a graphic format for nutrition labeling: three studies supported the use of bar graphs and one study supported the use of a pie chart. Full disclosure (ie, complete nutrient and ingredient labeling) was preferred by consumers in two of the three studies that examined this variable. The third study supported three types of information disclosure dependent upon socioeconomic class. In those studies that tested graphics, a bar graph format was significantly preferred and showed better consumer comprehension than the traditional format.

  14. Automation of Tabular Application Formation

    S. V. Zykin

    2013-01-01

    Full Text Available The paper considers automation problems of the interface formation between a table and a relational database. The task description is formalized and the description of the existing approaches to formation of data representations on an example of widely widespread CASE-tools is submitted. The definition of intermediate data representation as a ”join table” is offered, which is used for maintenance of correctness of data representation formation, and also is necessary for direct and inverse data transformations. On the basis of lossless join property and realized dependencies, the concept and a way of context formation of the application and restrictions is introduced. The considered material is further used for constructing an inverse data transformation from tabular presentation into a relational one. On the basis of relationships properties on a database scheme, the partial order on the relations is established, and the restriction of acyclic databases schemes is introduced. The received results are further used at the analysis of principles of formation of inverse data transformation, and the basic details of such a transformation algorithm are considered.

  15. Formative assessment: a student perspective.

    Hill, D A; Guinea, A I; McCarthy, W H

    1994-09-01

    An educator's view would be that formative assessment has an important role in the learning process. This study was carried out to obtain a student perspective of the place of formative assessment in the curriculum. Final-year medical students at Royal Prince Alfred Hospital took part in four teaching sessions, each structured to integrate teaching with assessment. Three assessment methods were used; the group objective structured clinical examination (G-OSCE), structured short answer (SSA) questions and a pre/post-test multiple choice questionnaire (MCQ). Teaching sessions were conducted on the subject areas of traumatology, the 'acute abdomen', arterial disorders and cancer. Fifty-five students, representing 83% of those who took part in the programme, responded to a questionnaire where they were asked to rate (on a 5-point Likert scale) their response to general questions about formative assessment and 13 specific questions concerning the comparative value of the three assessment modalities. Eighty-nine per cent of respondents felt that formative assessment should be incorporated into the teaching process. The SSA assessment was regarded as the preferred modality to reinforce previous teaching and test problem-solving skills. The MCQ was the least favoured assessment method. The effect size variable between the total scores for the SSA and MCQ was 0.64. The variable between G-OSCE and SSA/MCQ was 0.26 and 0.33 respectively. Formative assessment is a potentially powerful method to direct learning behaviour. Students should have input into the methods used.

  16. The Physics of Planetesimal Formation

    Simon, Jacob; Armitage, Philip; Youdin, Andrew; Li, Rixin

    2015-12-01

    Planetesimals are the precursors to planets, and understanding their formation is an essential step towards developing a complete theory of planet formation. For small solid particles (e.g., dust grains) to coagulate into planetesimals, however, requires that these particles grow beyond centimeter sizes; with traditional coagulation physics, this is very difficult. The streaming instability, which is a clumping process akin to the pile-up of cars in a traffic jam, generates sufficiently high solid densities that the mutual gravity between the clumped particles eventually causes their collapse towards planetesimal mass and size scales. Exploring this transition from dust grains to planetesimals is still in its infancy but is extremely important if we want to understand the basics of planet formation. Here, I present a series of high resolution, first principles numerical simulations of potoplanetary disk gas and dust to study the clumping of particles via the streaming instability and the subsequent collapse towards planetesimals. These simulations have been employed to characterize the planetesimal population as a function of radius in protoplanetary disks. The results of these simulations will be crucial for planet formation models to correctly explain the formation and configuration of solar systems.

  17. Simulated Patterns of Unforced Centennial-Scale Climate Variability in the Tropical Pacific

    Sahoo, S. K.; Jiang, G.; Planavsky, N. J.; Kendall, B.; Owens, J. D.; Anbar, A. D.; Lyons, T. W.

    2011-12-01

    Evidence for pervasive oxic conditions, and likely even deep ocean oxygenation has been documented at three intervals in the lower (ca. 632 Ma), middle (ca. 580 Ma) and upper (ca. 551 Ma) Ediacaran. The Doushantuo Formation in South China hosts large enrichments of redox-sensitive trace element (e.g., molybdenum, vanadium and uranium) in anoxic shales, which are indicative of a globally oxic ocean-atmosphere system. However, ocean redox conditions between these periods continue to be a topic of debate and remain elusive. We have found evidence for widespread anoxic conditions through much of the Ediacaran in the deep-water Wuhe section in South China. During most of the Ediacaran-early Cambrian in basinal sections is characterized by Fe speciation data and pyrite morphologies that indicate deposition under euxinic conditions with near-crustal enrichments of redox-sensitive element and positive pyrite-sulfur isotope values, which suggest low levels of marine sulfate and widespread euxinia. Our work reinforces an emerging view that the early Earth, including the Ediacaran, underwent numerous rises and falls in surface oxidation state, rather than a unidirectional rise as originally imagined. The Ediacaran ocean thus experienced repetitive expansion and contraction of marine chalcophilic trace-metal levels that may have had fundamental impact on the slow evolution of early animals and ecosystems. Further, this framework forces us to re-examine the relationship between Neoproterozoic oxygenation and metazoan diversification. Varying redox conditions through the Cryogenian and Ediacaran may help explain molecular clock and biomarker evidence for an early appearance and initial diversification of metazoans but with a delay in the appearance of most major metazoan crown groups until close to Ediacaran-Cambrian boundary.

  18. Exoplanets Detection, Formation, Properties, Habitability

    Mason, John W

    2008-01-01

    This edited, multi-author volume will be an invaluable introduction and reference to all key aspects in the field of exoplanet research. The reviews cover: Detection methods and properties of known exoplanets, Detection of extrasolar planets by gravitational microlensing. The formation and evolution of terrestrial planets in protoplanetary and debris disks. The brown dwarf-exoplanet connection. Formation, migration mechanisms and properties of hot Jupiters. Dynamics of multiple exoplanet systems. Doppler exoplanet surveys. Searching for exoplanets in the stellar graveyard. Formation and habitability of extra solar planets in multiple star systems. Exoplanet habitats and the possibilities for life. Moons of exoplanets: habitats for life. Contributing authors: •Rory Barnes •David P. Bennett •Jian Ge •Nader Haghighipour •Patrick Irwin •Hugh Jones •Victoria Meadows •Stanimir Metchev •I. Neill Reid •George Rieke •Caleb Scharf •Steinn Sigurdsson

  19. Modularity in New Market Formation

    Sanchez, Ron; Hang, Chang Chieh

    2017-01-01

    In this paper we appraise the ways in which use of closed-system proprietary product architectures versus open-system modular product architectures is likely to influence the dynamics and trajectory of new product market formation. We compare the evolutions of new markets in China for gas......-powered two-wheeled vehicles (G2WVs) based (initially) on closed-system proprietary architectures and for electric-powered two-wheeled vehicles (E2WVs) based on open-system modular architectures. We draw on this comparison to suggest ways in which the use of the two different kinds of architectures...... as the basis for new kinds of products may result in very different patterns and speeds of new market formation. We then suggest some key implications of the different dynamics of market formation associated with open-system modular architectures for both the competence-based strategic management (CBSM...

  20. Cosmic strings and galaxy formation

    Bertschinger, E.

    1989-01-01

    Cosmic strings have become increasingly popular candidates as seeds for the formation of structure in the universe. This scenario, remains a serious cosmogonical model despite close scrutiny. In constrast, magnetic monopoles and domain walls - relic topological defects as are cosmic strings - are disastrous for cosmology if they are left over from the early universe. The production of heavy cosmic strings is speculative, as it depends on the details of ultrahigh energy physics. Fortunately, speculation about cosmic strings is not entirely idle because, if they exist and are heavy enough to seed galaxy formation, cosmic strings can be detected astronomically. Failure to detect cosmic strings would impose some constraints on grand unified theories (GUTs); their discovery would have exciting consequences for high energy physics and cosmology. This article reviews the basic physics of nonsuperconducting cosmic strings, highlighting the field theory aspects, and provides a progress report on calculations of structure formation with cosmic strings

  1. 'TV Format Protection through Marketing Strategies?'

    Singh, Sukhpreet

    2008-01-01

    Commercially successful programme ideas are often imitated or adapted. Television formats, in particular, are routinely copied. Starting from radio formats in the 1950s to game shows and reality programme formats of today, producers have accused others of “stealing”. Although formats constitute one of the most important exports for British TV producers, there is still no certainty about the legal protection of TV formats from copycat versions. Since TV formats fail to fall neatly within the d...

  2. Regulation of Reactionary Dentine Formation.

    Neves, V C M; Sharpe, P T

    2018-04-01

    During the treatment of dental caries that has not penetrated the tooth pulp, maintenance of as much unaffected dentine as possible is a major goal during the physical removal of decayed mineral. Damage to dentine leads to release of fossilized factors (transforming growth factor-β [TGF-β] and bone morphogenic protein [BMP]) in the dentine that are believed to stimulate odontoblasts to secrete new "tertiary" dentine (reactionary dentine). This is formed on the pulpal surface of existing dentine and rethickens the dentine. We have previously shown that activation of Wnt/β-catenin signaling is pivotal for tooth repair in exposed pulp injury, and the pathway can be activated by small-molecule GSK-3 antagonists, resulting in enhanced reparative dentine formation. Here, we use a nonexposed pulp injury model to investigate the mechanisms of reactionary dentine formation in vivo, using small molecules to modulate the Wnt/β-catenin, TGF-β, and BMP pathways. We found that a local increase of Wnt activation at the injury site enhances reactionary dentine secretion. In addition, inhibition of TGF-β, BMP, or Wnt pathways does not impede reactionary dentine formation, although inhibition of TGF-β and/or BMP signaling does result in more disorganized, nontubular reactionary dentine. This suggests that Wnt/β-catenin signaling plays no major role in the formation of reactionary dentine, but in common with reparative dentine formation, exogenous elevation of Wnt/β-catenin signaling can enhance tertiary dentine formation. Release of latent TGF-β or BMPs from dentine is not required for the deposition of mineral to form reactionary dentine but does play a role in its organization.

  3. Radionuclide migration in geological formations

    Barbreau, A.; Heremans, R.; Skytte Jensen, B.

    1980-01-01

    Radioactive waste disposal into geological formation is based on the capacity of rocks to confine radioactivity for a long period of time. Radionuclide migration from the repository to the environment depends on different mechanisms and phenomena whose two main ones are groundwater flow and the retention and ion-exchange property of rocks. Many studies are underway presently in EEC countries concerning hydrodynamic characteristics of deep geological formations as well as in radionuclide retention capacity and modelling. Important results have already been achieved which show the complexity of some phenomena and further studies shall principally be developed taking into account real conditions of the repository and its environment

  4. Pattern formations and oscillatory phenomena

    Kinoshita, Shuichi

    2013-01-01

    Patterns and their formations appear throughout nature, and are studied to analyze different problems in science and make predictions across a wide range of disciplines including biology, physics, mathematics, chemistry, material science, and nanoscience. With the emergence of nanoscience and the ability for researchers and scientists to study living systems at the biological level, pattern formation research has become even more essential. This book is an accessible first of its kind guide for scientists, researchers, engineers, and students who require a general introduction to thi

  5. The formation of ice sails

    Fowler, A. C.; Mayer, C.

    2017-11-01

    Debris-covered glaciers are prone to the formation of a number of supraglacial geomorphological features, and generally speaking, their upper surfaces are far from level surfaces. Some of these features are due to radiation screening or enhancing properties of the debris cover, but theoretical explanations of the consequent surface forms are in their infancy. In this paper we consider a theoretical model for the formation of "ice sails", which are regularly spaced bare ice features which are found on debris-covered glaciers in the Karakoram.

  6. Market formation and market selection

    van Raalte, C.L.J.P.

    1996-01-01

    The organization of markets is an important field of inquiry in modern economic theory. This monograph analyzes models which consider the formation and selection of markets. In these models, markets are organized by middlemen and used by traders. In Part I of the monograph, coalitions of middlemen

  7. A Model of Partnership Formation

    Talman, A.J.J.; Yang, Z.F.

    2008-01-01

    This paper presents a model of partnership formation. A set of agents wants to conduct some business or other activities. Agents may act alone or seek a partner for cooperation and need in the latter case to consider with whom to cooperate and how to share the profit in a collaborative and

  8. The Road to Galaxy Formation

    Keel, William C

    2007-01-01

    The formation of galaxies is one of the greatest puzzles in astronomy, the solution is shrouded in the depths of space and time, but has profound implications for the universe we observe today. The book discusses the beginnings of the process from cosmological observations and calculations, considers the broad features of galaxies that we need to explain and what we know of their later history. The author compares the competing theories for galaxy formation and considers the progress expected from new generations of powerful telescopes both on earth and in space. In this second edition the author has retained the observationally-based approach of the first edition, a feature which was particularly well-reviewed: Writing in Nature, Carlton Baugh noted in February 2003 that “It is refreshing, in a market dominated by theorists, to come across a book on galaxy formation written from an observational perspective. The Road to Galaxy Formation should prove to be a handy primer on observations for graduate student...

  9. Analysis of Disulfide Bond Formation

    Braakman, Ineke; Lamriben, Lydia; van Zadelhoff, Guus; Hebert, Daniel N.

    2017-01-01

    In this unit, protocols are provided for detection of disulfide bond formation in cultures of intact cells and in an in vitro translation system containing isolated microsomes or semi-permeabilized cells. First, the newly synthesized protein of interest is biosynthetically labeled with radioactive

  10. A model of partnership formation

    Talman, A.J.J.; Yang, Z.F.

    2011-01-01

    This paper presents a model of partnership formation. A number of agents want to conduct some business or other activities. Agents may act alone or seek a partner for cooperation and need in the latter case to consider with whom to cooperate and how to share the profit in a collaborative and

  11. Is All Formative Influence Immoral?

    Tillson, John

    2018-01-01

    Is it true that all formative influence is unethical, and that we ought to avoid influencing children (and indeed anyone at all)? There are more or less defensible versions of this doctrine, and we shall follow some of the strands of argument that lead to this conclusion. It seems that in maintaining that all influence is immoral, one commits…

  12. Exciton Formation in Disordered Semiconductors

    Klochikhin, A.; Reznitsky, A.; Permogorov, S.

    1999-01-01

    Stationary luminescence spectra of disordered solid solutions can be accounted by the model of localized excitons. Detailed analysis of the long time decay kinetics of luminescence shows that exciton formation in these systems is in great extent due to the bimolecular reaction of separated carrie...

  13. Auditory and phonetic category formation

    Goudbeek, Martijn; Cutler, A.; Smits, R.; Swingley, D.; Cohen, Henri; Lefebvre, Claire

    2017-01-01

    Among infants' first steps in language acquisition is learning the relevant contrasts of the language-specific phonemic repertoire. This learning is viewed as the formation of categories in a multidimensional psychophysical space. Research in the visual modality has shown that for adults, some kinds

  14. Facial Prototype Formation in Children.

    Inn, Donald; And Others

    This study examined memory representation as it is exhibited in young children's formation of facial prototypes. In the first part of the study, researchers constructed images of faces using an Identikit that provided the features of hair, eyes, mouth, nose, and chin. Images were varied systematically. A series of these images, called exemplar…

  15. Mantle dynamics following supercontinent formation

    Heron, Philip J.

    This thesis presents mantle convection numerical simulations of supercontinent formation. Approximately 300 million years ago, through the large-scale subduction of oceanic sea floor, continental material amalgamated to form the supercontinent Pangea. For 100 million years after its formation, Pangea remained relatively stationary, and subduction of oceanic material featured on its margins. The present-day location of the continents is due to the rifting apart of Pangea, with supercontinent dispersal being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The work presented here investigates the thermal evolution of mantle dynamics (e.g., mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Specifically, continental insulation and continental margin subduction are analyzed. Continental material, as compared to oceanic material, inhibits heat flow from the mantle. Previous numerical simulations have shown that the formation of a stationary supercontinent would elevate sub-continental mantle temperatures due to the effect of continental insulation, leading to the break-up of the continent. By modelling a vigorously convecting mantle that features thermally and mechanically distinct continental and oceanic plates, this study shows the effect of continental insulation on the mantle to be minimal. However, the formation of a supercontinent results in sub-continental plume formation due to the re-positioning of subduction zones to the margins of the continent. Accordingly, it is demonstrated that continental insulation is not a significant factor in producing sub-supercontinent plumes but that subduction patterns control the location and timing of upwelling formation. A theme throughout the thesis is an inquiry into why geodynamic studies would produce different results. Mantle viscosity, Rayleigh number, continental size, continental insulation, and oceanic plate boundary evolution are

  16. Inside-out planet formation

    Chatterjee, Sourav; Tan, Jonathan C.

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ≳ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (∼cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ∼1 M ⊕ planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  17. Dioxin formation from waste incineration.

    Shibamoto, Takayuki; Yasuhara, Akio; Katami, Takeo

    2007-01-01

    There has been great concern about dioxins-polychlorinated dibenzo dioxins (PCDDs), polychlorinated dibenzo furans (PCDFs), and polychlorinated biphenyls (PCBs)-causing contamination in the environment because the adverse effects of these chemicals on human health have been known for many years. Possible dioxin-contamination has received much attention recently not only by environmental scientists but also by the public, because dioxins are known to be formed during the combustion of industrial and domestic wastes and to escape into the environment via exhaust gases from incinerators. Consequently, there is a pressing need to investigate the formation mechanisms or reaction pathways of these chlorinated chemicals to be able to devise ways to reduce their environmental contamination. A well-controlled small-scale incinerator was used for the experiments in the core references of this review. These articles report the investigation of dioxin formation from the combustion of various waste-simulated samples, including different kinds of paper, various kinds of wood, fallen leaves, food samples, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene chloride, polyethylene tetraphthalate (PET), and various kinds of plastic products. These samples were also incinerated with inorganic chlorides (NaCl, KCl, CuCI2, MgCl2, MnCl2, FeCl2, CoCl2, fly ash, and seawater) or organic chlorides (PVC, chlordane, and pentachlorophenol) to investigate the role of chlorine content and/or the presence of different metals in dioxin formation. Some samples, such as newspapers, were burned after they were impregnated with NaCl or PVC, as well as being cocombusted with chlorides. The roles of incineration conditions, including chamber temperatures, O2 concentrations, and CO concentrations, in dioxin formation were also investigated. Dioxins (PCDDs, PCDFs, and coplanar-PCBs) formed in the exhaust gases from a controlled small-scale incinerator, where experimental waste

  18. Consensus formation on coevolving networks: groups' formation and structure

    Kozma, Balazs; Barrat, Alain

    2008-01-01

    We study the effect of adaptivity on a social model of opinion dynamics and consensus formation. We analyse how the adaptivity of the network of contacts between agents to the underlying social dynamics affects the size and topological properties of groups and the convergence time to the stable final state. We find that, while on static networks these properties are determined by percolation phenomena, on adaptive networks the rewiring process leads to different behaviors: adaptive rewiring fosters group formation by enhancing communication between agents of similar opinion, though it also makes possible the division of clusters. We show how the convergence time is determined by the characteristic time of link rearrangement. We finally investigate how the adaptivity yields nontrivial correlations between the internal topology and the size of the groups of agreeing agents

  19. Stratigraphy and dissolution of the Rustler Formation

    Bachman, G.O.

    1987-01-01

    This report describes the physical stratigraphy of the Rustler Formation, because the Waste Isolation Pilot Plant will be constructed in salt beds that underlie this formation. Described are subdivisions of the formations, the major karst features, and a proposed method for the formation of Nash Draw. 2 refs., 2 figs

  20. Track formation. Principles and applications

    Monnin, M.

    1978-01-01

    The principles and technical aspects of track formation in insulating solids are first described. The characteristics of dialectic track detection are discussed from the technical point of view: the nature of the detectors, the chemical treatment, the sensitivity and the environmental conditions of use. The applications are reviewed. The principle of each type of applied research is described and then the applications are listed. When used as a detector, nuclear tracks can provide valuable information in a number of fields: element content determination and wrapping, imaging, radiation dosimetry, environmental studies, technological uses and miscellaneous other applications. The track-formation process can also be used for making well-defined holes; this method allows other applications which are also described. Finally, some possible future applications are mentioned. (author)

  1. Nuclear processing during star formation

    Newman, M.J.

    1978-01-01

    A preliminary survey was conducted of the thermonuclear energy release expected during star formation. The destruction of primordial deuterium provides substantial amounts of energy at surprisingly low temperatures, and must be considered in any meaningful treatment of star formation carried to stages in which the internal temperature exceeds a few hundred thousand degrees. Significant energy generation from consumption of initial lithium requires higher temperatures, of the order of a few million degrees. Depletion of primordial beryllium and boron may never provide an important energy source. The approach to equilibrium of the carbon--nitrogen cycle is dominant at temperatures approaching those characteristic of the central regions of main sequence stars. The present calculation should serve as a useful guide in choosing those nuclear processes to be included in a more detailed study. 8 figures, 2 tables

  2. Coevolutionary modeling in network formation

    Al-Shyoukh, Ibrahim

    2014-12-03

    Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

  3. Star Formation in Dusty Quasars

    Lumsden, Stuart; Croom, Scott

    2012-04-01

    Quasar mode feedback is thought to be a crucial ingredient in galaxy formation for luminous merging and star-bursting systems at high redshift. The energy from the active nucleus should cause significant gas outflows, reducing the available free gas reservoir for future star formation. It is currently unknown which observational state best corresponds to the stage at which this "blowout" should occur. We intend to test one possible source population for this transition phase, by studying the molecular gas content in a small, statistically complete sample of 3 K-band selected reddened quasars from the AUS survey. All lie in the redshift range 2

  4. Method for consolidating incompetent formations

    Pavlich, J.P.; Calvert, D.G.

    1965-02-23

    An incompetent formation is consolidated and left permeable by first injecting a solidifiable liquid resin, and following this by an organic liquid to set the resin. The liquid resin used may be 3 (glycidyloxy) propyl trimethoxysilane in sufficient concentration to considerably increase the compressive strength of the consolidated zone. The silane may be used in a ratio of between 0.5 and 5% of the total volume of the liquid resin. The liquid resin used may be a phenol-formaldehyde condensation product dispersed in an aliphatic alcohol with from 1 to 4 carbon atoms. The liquid resin used may be an epoxy containing a hardener. The resin may be displaced into the formation by a liquid hydrocarbon. (5 claims)

  5. Othering, identity formation and agency

    Sune Qvotrup Jensen

    2011-10-01

    Full Text Available The article examines the potentials of the concept of othering to describe identity formation among ethnic minorities. First, it outlines the history of the concept, its contemporary use, as well as some criticisms. Then it is argued that young ethnic minority men in Denmark are subject to intersectional othering, which contains elements of exoticist fascination of the other. On the basis of ethnographic material, it is analysed how young marginalized ethnic minority men react to othering. Two types of reactions are illustrated: 1 capitalization on being positioned as the other, and 2 refusing to occupy the position of the other by disidentification and claims to normality. Finally, it is argued that the concept of othering is well suited for understanding the power structures as well as the historic symbolic meanings conditioning such identity formation, but problematic in terms of agency.

  6. Coevolutionary modeling in network formation

    Al-Shyoukh, Ibrahim; Chasparis, Georgios; Shamma, Jeff S.

    2014-01-01

    Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

  7. THE BLACK HOLE FORMATION PROBABILITY

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D., E-mail: dclausen@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, Mailcode 350-17, Pasadena, CA 91125 (United States)

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P {sub BH}(M {sub ZAMS}). Although we find that it is difficult to derive a unique P {sub BH}(M {sub ZAMS}) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P {sub BH}(M {sub ZAMS}) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P {sub BH}(M {sub ZAMS}) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  8. A study on frost formation

    青木, 和夫

    1986-01-01

    When humid air is exposed to a cold surface whose temperature is below 0 \\C\\, frost deposition occurs and continues to accumulate on the surface. Frost deposition is an important phenomenon in cryogenic industries for use in air conditioners, refrigerators and freeze-out purification, because it causes the drop of thermal efficiency on heat exchangers.This paper presented a review of our previous studies on frost formation with emphasis on the frost growth process, the frost structure, the gr...

  9. Debris Disks: Probing Planet Formation

    Wyatt, Mark C.

    2018-01-01

    Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on circumstellar disk evolution and the outcome of planet formation. The debris disk population can be explained by the steady collisional erosion of planetesimal belts; population models constrain where (10-100au) and in what quantity (>1Mearth) planetesimals (>10km i...

  10. Kinetically guided colloidal structure formation

    Hecht, Fabian M.; Bausch, Andreas R.

    2016-01-01

    The well-studied self-organization of colloidal particles is predicted to result in a variety of fascinating applications. Yet, whereas self-assembly techniques are extensively explored, designing and producing mesoscale-sized objects remains a major challenge, as equilibration times and thus structure formation timescales become prohibitively long. Asymmetric mesoscopic objects, without prior introduction of asymmetric particles with all its complications, are out of reach––due to the underl...

  11. Formation of a collaborative society

    Buřita, Ladislav; Ondryhal, Vojtěch

    2014-01-01

    The MilUNI knowledge portal, based on the knowledge base developed in ATOM software has been created at the authors' workplace with the aim to form a collaborative society of military universities. The analysis of the collaborative society concept is presented. The description of the MilUNI project is included. Some areas for university cooperation are proposed, as well as the measures facilitating the formation and development of the collaborative society.

  12. THE BLACK HOLE FORMATION PROBABILITY

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-01-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH (M ZAMS ). Although we find that it is difficult to derive a unique P BH (M ZAMS ) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH (M ZAMS ) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH (M ZAMS ) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment

  13. The Black Hole Formation Probability

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH(M ZAMS). Although we find that it is difficult to derive a unique P BH(M ZAMS) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH(M ZAMS) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH(M ZAMS) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  14. Interactions, Starbursts, and Star Formation

    Johan H. Knapen

    2015-12-01

    Full Text Available We study how interactions between galaxies affect star formation within them by considering a sample of almost 1500 of the nearest galaxies, all within a distance of ∼45 Mpc. We use the far-IR emission to define the massive star formation rate (SFR, and then normalise the SFR by the stellar mass of the galaxy to obtain the specific star formation rate (SSFR. We explore the distribution of (SSFR with morphological type and with stellar mass. We calculate the relative enhancement of SFR and SSFR for each galaxy by normalising them by the median SFR and SSFR values of individual control samples of similar non-interacting galaxies. We find that both the median SFR and SSFR are enhanced in interacting galaxies, and more so as the degree of interaction is higher. The increase is moderate, reaching a maximum of a factor of 1.9 for the highest degree of interaction (mergers. While the SFR and SSFR are enhanced statistically by interactions, in many individual interacting galaxies they are not enhanced at all. Our study is based on a representative sample of nearby galaxies and should be used to place constraints on studies based on samples of galaxies at larger distances.

  15. Pattern formation in optical resonators

    Weiss, C O; Larionova, Ye

    2007-01-01

    We review pattern formation in optical resonators. The emphasis is on 'particle-like' structures such as vortices or spatial solitons. On the one hand, similarities impose themselves with other fields of physics (condensed matter, phase transitions, particle physics, fluds/super fluids). On the other hand the feedback is led by the resonator mirrors to bi- and multi-stability of the spatial field structure, which is the basic ingredient for optical information processing. The spatial dimension or the 'parallelism' is the strength of optics compared to electronics (and will have to be employed to fully use the advantages optics offers in information processing). But even in the 'serial' processing tasks of telecoms (e.g. information buffering) spatial resonator solitons can do better than the schemes proposed so far-including 'slow light'. Pattern formation in optical resonators will likely be the key to brain-like information processing like cognition, learning and association; to complement the precise but limited algorithmic capabilities of electronic processing. But even in the short term it will be useful for solving serial optical processing problems. The prospects for technical uses of pattern formation in resonators are one motivation for this research. The fundamental similarities with other fields of physics, on the other hand, inspire transfer of concepts between fields; something that has always proven fruitful for gaining deeper insights or for solving technical problems

  16. Formation mechanisms of metal colloids

    Halaciuga, Ionel

    Highly dispersed uniform metallic particles are widely used in various areas of technology and medicine and are likely to be incorporated into many other applications in the future. It is commonly accepted that size, shape and composition of the particles represent critical factors in most applications. Thus, understanding the mechanisms of formation of metal particles and the ways to control the physical (e.g. shape, size) and chemical (e.g. composition) properties is of great importance. In the current research, the formation of uniform silver spheres is investigated experimentally. The parameters that influence the formation of silver particles when concentrated iso-ascorbic acid and silver-polyamine complex solutions are rapidly mixed were studied in the absence of dispersants. We found that by varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, the size of the resulting silver particles can be varied in a wide range (0.08--1.5 microm). The silver particles were formed by aggregation of nanosize subunits as substantiated by both electron microscopy and X-ray diffraction techniques and by the vivid rapid color changes during the chemical precipitation process. From the practical standpoint, the goal of this research was to prepare well dispersed spherical silver particles having a relatively smooth surface and a diameter of about 1 microm to satisfy the demands of the current electronic materials market. A two stage particle growth model previously developed to explain the narrow size distribution occurring in synthesis of gold spheres was applied to the present experimental system, and the parameters that control the size distribution characteristics were identified. The kinetic parameter required to match the final particle size was found to be in agreement with the one used previously in modeling formation of gold spheres, suggesting that similar kinetics governs the

  17. Dyes adsorption blue vegetable and blue watercolor by natural zeolites modified with surfactants;Adsorcion de colorantes azul vegetal y azul acuarela por zeolitas naturales modificadas con surfactantes

    Jardon S, C. C.; Olguin G, M. T. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Diaz N, M. C., E-mail: teresa.olguin@inin.gob.m [Instituto Tecnologico de Toluca, Av. Instituto Tecnologico s/n, Ex-Rancho la Virgen, 52140 Metepec, Estado de Mexico (Mexico)

    2009-07-01

    In this work was carried out the dyes removal blue vegetable and blue watercolor of aqueous solutions, to 20 C, at different times and using a zeolite mineral of Parral (Chihuahua, Mexico) modified with hexadecyl trimethyl ammonium bromide or dodecyl trimethyl ammonium bromide. The zeolite was characterized before and after of its adaptation with NaCl and later with HDTMABr and DTMABr. For the materials characterization were used the scanning electron microscopy of high vacuum; elementary microanalysis by X-ray spectroscopy of dispersed energy and X-ray diffraction techniques. It was found that the surfactant type absorbed in the zeolite material influences on the adsorption process of the blue dye. Likewise, the chemical structure between the vegetable blue dye and the blue watercolor, determines the efficiency of the color removal of the water, by the zeolites modified with the surfactants. (Author)

  18. Adsorption-induced step formation

    Thostrup, P.; Christoffersen, Ebbe; Lorensen, Henrik Qvist

    2001-01-01

    Through an interplay between density functional calculations, Monte Carlo simulations and scanning tunneling microscopy experiments, we show that an intermediate coverage of CO on the Pt(110) surface gives rise to a new rough equilibrium structure with more than 50% step atoms. CO is shown to bind...... so strongly to low-coordinated Pt atoms that it can break Pt-Pt bonds and spontaneously form steps on the surface. It is argued that adsorption-induced step formation may be a general effect, in particular at high gas pressures and temperatures....

  19. Formation fracturing by energy waves

    Brandon, C W

    1966-11-28

    A method described for recovering oil from an oil strata penetrated by a well bore includes a step of applying fluid pressure to the interior of the well bore across the face of the stratum, and alternately varying the applied fluid pressure, first above and then below the reservoir pressure. This is in order to fracture and break up the face of the strata from internal pressure exerted on the strata. The pressure is affected using liquefied gas at low pressure across the formation.

  20. Formation Flying and Deformable Instruments

    Rio, Yvon

    2009-01-01

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  1. Formation Flying and Deformable Instruments

    Rio, Yvon

    2009-05-01

    Astronomers have always attempted to build very stable instruments. They fight all that can cause mechanical deformation or image motion. This has led to well established technologies (autoguide, active optics, thermal control, tip/tilt correction), as well as observing methods based on the use of controlled motion (scanning, micro scanning, shift and add, chopping and nodding). Formation flying disturbs this practice. It is neither possible to reduce the relative motion to very small amplitudes, nor to control it at will. Some impacts on Simbol-X instrument design, and operation are presented.

  2. Formative flow in bedrock canyons

    Venditti, J. G.; Kwoll, E.; Rennie, C. D.; Church, M. A.

    2017-12-01

    In alluvial channels, it is widely accepted that river channel configuration is set by a formative flow that represents a balance between the magnitude and frequency of flood flows. The formative flow is often considered to be one that is just capable of filling a river channel to the top of its banks. Flows much above this formative flow are thought to cause substantial sediment transport and rearrange the channel morphology to accommodate the larger flow. This idea has recently been extended to semi-alluvial channels where it has been shown that even with bedrock exposed, the flows rarely exceed that required to entrain the local sediment cover. What constitutes a formative flow in a bedrock canyon is not clear. By definition, canyons have rock walls and are typically incised vertically, removing the possibility of the walls being overtopped, as can occur in an alluvial channel at high flows. Canyons are laterally constrained, have deep scour pools and often have width to maximum depth ratios approaching 1, an order of magnitude lower than alluvial channels. In many canyons, there are a sequence of irregularly spaced scour pools. The bed may have intermittent or seasonal sediment cover, but during flood flows the sediment bed is entrained leaving a bare bedrock channel. It has been suggested that canyons cut into weak, well-jointed rock may adjust their morphology to the threshold for block plucking because the rock bed is labile during exceptionally large magnitude flows. However, this hypothesis does not apply to canyons cut into massive crystalline rock where abrasion is the dominant erosion process. Here, we argue that bedrock canyon morphology is adjusted to a characteristic flow structure developed in bedrock canyons. We show that the deeply scoured canyon floor is adjusted to a velocity inversion that is present at low flows, but gets stronger at high flows. The effect is to increase boundary shear stresses along the scour pool that forms in constricted

  3. Transient formation of forbidden lines

    Rosmej, F.B.; Rosmej, O.N.

    1996-01-01

    An explanation of anomalously long time scales in the transient formation of forbidden lines is proposed. The concept is based on a collisionally induced density dependence of the relaxation times of metastable level populations in transient plasma. Generalization leads to an incorporation of diffusion phenomena. We demonstrate this new concept for the simplest atomic system: the He-like isoelectronic sequence. A new interpretation of the observed long duration and anomalously high intensity of spin-forbidden emission in hot plasmas is given. (author)

  4. Salt formations offer disposal alternative

    Funderburk, R.

    1990-01-01

    This paper discusses how three U.S. firms are spending millions to permit and build underground disposal sites in salt formations. These companies claim salt is the ideal geological medium for holding hazardous wastes. Two Texas locations and one in Michigan have been targeted as future sites for hazardous waste disposal. The Michigan site, outside Detroit, is a former salt mine 2,000 feet beneath the Ford Motor Co. (Detroit) assembly works in Dearborn. Both Texas sites are atop salt domes---one east and one west of Houston

  5. Transient formation of forbidden lines

    Rosmej, F.B. [Bochum Univ., Ruhr (Germany). Inst. fuer Experimentalphysik V; Rosmej, O.N. [VNIIFTRI, Moscow Region (Russian Federation). MISDC

    1996-05-14

    An explanation of anomalously long time scales in the transient formation of forbidden lines is proposed. The concept is based on a collisionally induced density dependence of the relaxation times of metastable level populations in transient plasma. Generalization leads to an incorporation of diffusion phenomena. We demonstrate this new concept for the simplest atomic system: the He-like isoelectronic sequence. A new interpretation of the observed long duration and anomalously high intensity of spin-forbidden emission in hot plasmas is given. (author).

  6. Tube Formation in Nanoscale Materials

    Yan Chenglin

    2008-01-01

    Full Text Available Abstract The formation of tubular nanostructures normally requires layered, anisotropic, or pseudo-layered crystal structures, while inorganic compounds typically do not possess such structures, inorganic nanotubes thus have been a hot topic in the past decade. In this article, we review recent research activities on nanotubes fabrication and focus on three novel synthetic strategies for generating nanotubes from inorganic materials that do not have a layered structure. Specifically, thermal oxidation method based on gas–solid reaction to porous CuO nanotubes has been successfully established, semiconductor ZnS and Nb2O5nanotubes have been prepared by employing sacrificial template strategy based on liquid–solid reaction, and an in situ template method has been developed for the preparation of ZnO taper tubes through a chemical etching reaction. We have described the nanotube formation processes and illustrated the detailed key factors during their growth. The proposed mechanisms are presented for nanotube fabrication and the important pioneering studies are discussed on the rational design and fabrication of functional materials with tubular structures. It is the intention of this contribution to provide a brief account of these research activities.

  7. Supercoil Formation During DNA Melting

    Sayar, Mehmet; Avsaroglu, Baris; Kabakcioglu, Alkan

    2009-03-01

    Supercoil formation plays a key role in determining the structure-function relationship in DNA. Biological and technological processes, such as protein synthesis, polymerase chain reaction, and microarrays relys on separation of the two strands in DNA, which is coupled to the unwinding of the supercoiled structure. This problem has been studied theoretically via Peyrard-Bishop and Poland-Scheraga type models, which include a simple representation of the DNA structural properties. In recent years, computational models, which provide a more realtistic representaion of DNA molecule, have been used to study the melting behavior of short DNA chains. Here, we will present a new coarse-grained model of DNA which is capable of simulating sufficiently long DNA chains for studying the supercoil formation during melting, without sacrificing the local structural properties. Our coarse-grained model successfully reproduces the local geometry of the DNA molecule, such as the 3'-5' directionality, major-minor groove structure, and the helical pitch. We will present our initial results on the dynamics of supercoiling during DNA melting.

  8. Vascular pattern formation in plants.

    Scarpella, Enrico; Helariutta, Ykä

    2010-01-01

    Reticulate tissue systems exist in most multicellular organisms, and the principles underlying the formation of cellular networks have fascinated philosophers, mathematicians, and biologists for centuries. In particular, the beautiful and varied arrangements of vascular tissues in plants have intrigued mankind since antiquity, yet the organizing signals have remained elusive. Plant vascular tissues form systems of interconnected cell files throughout the plant body. Vascular cells are aligned with one another along continuous lines, and vascular tissues differentiate at reproducible positions within organ environments. However, neither the precise path of vascular differentiation nor the exact geometry of vascular networks is fixed or immutable. Several recent advances converge to reconcile the seemingly conflicting predictability and plasticity of vascular tissue patterns. A control mechanism in which an apical-basal flow of signal establishes a basic coordinate system for body axis formation and vascular strand differentiation, and in which a superimposed level of radial organizing cues elaborates cell patterns, would generate a reproducible tissue configuration in the context of an underlying robust, self-organizing structure, and account for the simultaneous regularity and flexibility of vascular tissue patterns. Copyright 2010 Elsevier Inc. All rights reserved.

  9. Beaver assisted river valley formation

    Westbrook, Cherie J.; Cooper, D.J.; Baker, B.W.

    2011-01-01

    We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. ?? 2010 John Wiley & Sons, Ltd.

  10. Enthalpy of formation of zircon

    Ellison, A.J.G.; Navrotsky, A.

    1992-01-01

    Using high-temperature solution calorimetry in molt 2PbO · B 2 O 3 , the enthalpy of reaction of the formation of zircon, ZrSiO 4 , from its constituent oxides has been determined: Δ 4 H 977 (ZrSiO 4 ) = -27.9 (±1.9) kJ/mol. With previously reported data for the heat contents of ZrO 2 SiO 2 and ZrSiO 4 and standard-state enthalpies of formation of ZrO 2 and SiO 2 , we obtain Δ f H 298 degrees. (ZrSiO 4 ) = -2034.2 (±3.1) kJ/mol and Δ t G 298 degrees (ZrSiO 4 ) = -1919.8 kJ/mol. The free energy value is in excellent agreement with a range previously estimated from solid-state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. In this paper the limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed

  11. Spiral branches and star formation

    Zasov, A.V.

    1974-01-01

    Origin of spiral branches of galaxies and formation of stars in them are considered from the point of view of the theory of the gravitational gas condensation, one of comparatively young theories. Arguments are presented in favour of the stellar condensation theory. The concept of the star formation of gas is no longer a speculative hypothesis. This is a theory which assumes quantitative verification and explains qualitatively many facts observed. And still our knowledge on the nature of spiral branches is very poor. It still remains vague what processes give origin to spiral branches, why some galaxies have spirals and others have none. And shapes of spiral branches are diverse. Some cases are known when spiral branches spread outside boundaries of galaxies themselves. Such spirals arise exclusively in the region where there are two or some interacting galaxies. Only first steps have been made in the explanation of the galaxy spiral branches, and it is necessary to carry out new observations and new theoretical calculations

  12. The Formation Mechanism of Hydrogels.

    Lu, Liyan; Yuan, Shiliang; Wang, Jing; Shen, Yun; Deng, Shuwen; Xie, Luyang; Yang, Qixiang

    2017-06-12

    Hydrogels are degradable polymeric networks, in which cross-links play a vital role in structure formation and degradation. Cross-linking is a stabilization process in polymer chemistry that leads to the multi-dimensional extension of polymeric chains, resulting in network structures. By cross-linking, hydrogels are formed into stable structures that differ from their raw materials. Generally, hydrogels can be prepared from either synthetic or natural polymers. Based on the types of cross-link junctions, hydrogels can be categorized into two groups: the chemically cross-linked and the physically cross-linked. Chemically cross-linked gels have permanent junctions, in which covalent bonds are present between different polymer chains, thus leading to excellent mechanical strength. Although chemical cross-linking is a highly resourceful method for the formation of hydrogels, the cross-linkers used in hydrogel preparation should be extracted from the hydrogels before use, due to their reported toxicity, while, in physically cross-linked gels, dissolution is prevented by physical interactions, such as ionic interactions, hydrogen bonds or hydrophobic interactions. Physically cross-linked methods for the preparation of hydrogels are the alternate solution for cross-linker toxicity. Both methods will be discussed in this essay. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Dark matter and galaxy formation

    Umemura, Masayuki

    1987-01-01

    We propose a hybrid model of universe for galaxy formation, that is, an Einstein- de Sitter universe dominated by two-component dark matter: massive neutrinos and cold dark matter. In this hybrid model, the first luminous objects are dwarf galaxies. The neutrino density fluctuations produce large-scale high density and low density regions, which consequently evolve to superclusters of galaxies and voids, respectively. Dwarf galaxies are formed preferentially in supercluster regions. In voids, the formation of dwarf galaxies is fairly suppressed by diffuse UV flux from QSOs, and instead a number of expanding clouds are born, which produce Lyα forest as seen in QSO spectra. Ordinary galaxies are expected to form as aggregations of dwarf galaxies. In this model, some galaxies are born also in voids, and they tend to evolve to spiral galaxies. Additionally, if the same number of globular clusters are formed in a dwarf, the specific globular cluster frequencies are expected to be much larger in ellipticals than in spirals. (author)

  14. Enamel formation and amelogenesis imperfecta.

    Hu, Jan C-C; Chun, Yong-Hee P; Al Hazzazzi, Turki; Simmer, James P

    2007-01-01

    Dental enamel is the epithelial-derived hard tissue covering the crowns of teeth. It is the most highly mineralized and hardest tissue in the body. Dental enamel is acellular and has no physiological means of repair outside of the protective and remineralization potential provided by saliva. Enamel is comprised of highly organized hydroxyapatite crystals that form in a defined extracellular space, the contents of which are supplied and regulated by ameloblasts. The entire process is under genetic instruction. The genetic control of amelogenesis is poorly understood, but requires the activities of multiple components that are uniquely important for dental enamel formation. Amelogenesis imperfecta (AI) is a collective designation for the variety of inherited conditions displaying isolated enamel malformations, but the designation is also used to indicate the presence of an enamel phenotype in syndromes. Recently, genetic studies have demonstrated the importance of genes encoding enamel matrix proteins in the etiology of isolated AI. Here we review the essential elements of dental enamel formation and the results of genetic analyses that have identified disease-causing mutations in genes encoding enamel matrix proteins. In addition, we provide a fresh perspective on the roles matrix proteins play in catalyzing the biomineralization of dental enamel. Copyright 2007 S. Karger AG, Basel.

  15. Package Formats for Preserved Digital Material

    Zierau, Eld

    2012-01-01

    This paper presents an investigation of the best suitable package formats for long term digital preservation. The choice of a package format for preservation is crucial for future access, thus a thorough analysis of choice is important. The investigation presented here covers setting up requireme......This paper presents an investigation of the best suitable package formats for long term digital preservation. The choice of a package format for preservation is crucial for future access, thus a thorough analysis of choice is important. The investigation presented here covers setting up...... requirements for package formats used for long term preserved digital material, and using these requirements as the basis for analysing a range of package formats. The result of the concrete investigation is that the WARC format is the package format best suited for the listed requirements. Fulfilling...

  16. Negative ion formation processes: A general review

    Alton, G.D.

    1990-01-01

    The principal negative ion formation processes will be briefly reviewed. Primary emphasis will be placed on the more efficient and universal processes of charge transfer and secondary ion formation through non-thermodynamic surface ionization. 86 refs., 20 figs

  17. FORMATE-BASED FLUIDS: FORMULATION AND APPLICATION

    Nediljka Gaurina-Međimurec

    2008-12-01

    Full Text Available Formate-based fluids has been successfully used in over hunders HPHT well operations since they introduced in field practice. They have many advantages when compared with conventional HPHT drilling and completion fluids such as: minimal formation damage, maintenance of additve properties at high temperatures, reduced hydraulic flow resistance, low potential for differential sticking, naturally lubricating, very low corrosion rates, biodegradable and pose little risk to the environment etc. Formate-based fluids can be applied during deep slim hole drilling, shale drilling, reservoir drilling, salt and gas hydrate formations drilling. The laboratory research was carried out to evaluate the rheological behavior of formate-based fluids as a function of temperature. Formate-based fluids were formulated using potassium formate brine, xanthan polymer, PAC, starch and calcium carbonate. Experimental results show that potassium formate improves the thermal stability of polymers.

  18. Satellite Formation Control Using Atmospheric Drag

    Hajovsky, Blake B

    2007-01-01

    This study investigates the use of a linear quadratic terminal controller to reconfigure satellite formations using atmospheric drag actuated control while minimizing the loss of energy of the formation...

  19. Formation of tax culture in Russia

    Halikova Je.A.

    2014-11-01

    Full Text Available This article deals with the mechanism of the formation of tax culture in Russia, moral and ethical principles, on which based the work of the tax authorities, given the author's idea of the formation of tax culture. We consider the institution of tax advice, its interaction with the tax authorities and its impact on the formation of tax culture.

  20. Formative Constructs Implemented via Common Factors

    Treiblmaier, Horst; Bentler, Peter M.; Mair, Patrick

    2011-01-01

    Recently there has been a renewed interest in formative measurement and its role in properly specified models. Formative measurement models are difficult to identify, and hence to estimate and test. Existing solutions to the identification problem are shown to not adequately represent the formative constructs of interest. We propose a new two-step…

  1. ENDF/B-5 formats manual 1984

    Kinsey, R; Magurno, B A

    1986-09-01

    The ENDF-5 Format, originally the format of the US Evaluated Nuclear Data File ENDF/B-5, was internationally recommended for the computer storage, processing and exchange of evaluated neutron nuclear data. The present document contains the original Formats Manual of 1979, updated with revisions of Nov. 1983. (author) Figs, tabs

  2. String Formatting Considered Harmful for Novice Programmers

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found…

  3. The forensics of fulgurite formation

    Pasek, Matthew A.; Pasek, Virginia D.

    2018-04-01

    Natural disasters such as forest fires can result in extensive and costly property damage. These events may be the result of a human error or system failure triggered by electrical discharge, and in such circumstances may form a fulgurite. Understanding fulgurites and their formation may be critical in determining the cause of the fire or other, shock-related event. Here we identify several distinguishing features of fulgurites formed in association with downed power lines, including the presence of melted conductors, transformation of quartz to cristobalite, and morphological differences including increased glass percentage and smaller internal voids. These features are consequences of how heat is transferred to and through a target rock material as it melts and forms a fulgurite, and are predicted from both first principles of diffusive heat transfer, and empirically-derived reaction kinetics for mineral transformations.

  4. The dynamics of fragment formation

    Keane, D.

    1994-09-01

    We demonstrate that in the Quantum Molecular Dynamics model, dynamical correlations can result in the production rate for final state nucleon clusters (and hence composite fragments) being higher than would be expected if statistics and the available phase space were dominant in determining composite formation. An intranuclear cascade or a Boltzmann-Uehling-Uhlenbeck model, combined with a statistical approach in the late stage of the collision to determine composites, provides an equivalent description only under limited conditions of centrality and beam energy. We use data on participant fragment production in Au + Au collisions in the Bevalac's BOS time projection chamber to map out the parameter space where statistical clustering provides a good description. In particular, we investigate momentum-space densities of fragments up to 4 He as a function of fragment transverse momentum, azimuth relative to the reaction plane, rapidity, multiplicity and beam energy

  5. Field experiments in salt formations

    Kuehn, K.

    1986-01-01

    Field experiments in salt formations started as early as 1965 with Project Salt Vault in the Lyons Mine, Kansas, U.S.A., and with the purchase of the Asse salt mine by the German Federal Government. Underground tests concentrated on the heat dissipation around buried high-level radioactive wastes and the geomechanical consequences of their disposal. Near-field investigations cover the properties of water and gas release, radiolysis and corrosion. Further objectives of field experiments are the development and underground testing of a handling system for high-level wastes. The performance of an underground test disposal for such wastes is not only considered to be necessary for technical and scientific reasons but also for improving public acceptance of the concept of radioactive waste disposal. (author)

  6. Complexity of formation in holography

    Chapman, Shira; Marrochio, Hugo; Myers, Robert C.

    2017-01-01

    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the ‘complexity of formation’ (DOI: 10.1103/PhysRevLett.116.191301; 10.1103/PhysRevD.93.086006), i.e. the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions d>2, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case d=2, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  7. Infrared Astronomy and Star Formation

    Evans, N.J.

    1985-01-01

    Infrared astronomy is a natural tool to use in studying star formation because infrared light penetrates the surrounding dust and because protostars are expected to emit infrared light. Infrared mapping and photometry have revealed many compact sources, often embedded in more extensive warm dust associated with a molecular cloud core. More detailed study of these objects is now beginning, and traditional interpretations are being questioned. Some compact sources are now thought to be density enhancements which are not self-luminous. Infrared excesses around young stars may not always be caused by circumstellar dust; speckle measurements have shown that at least some of the excess toward T Tauri is caused by an infrared companion. Spectroscopic studies of the dense, star-forming cores and of the compact objects themselves have uncovered a wealth of new phenomena, including the widespread occurence of energetic outflows. New discoveries with IRAS and with other planned infrared telescopes will continue to advance this field. (author)

  8. Strategy Formation in Eastern Jutland

    Olesen, Kristian

    2008-01-01

      In Eastern Jutland a strategy formation process has been initiated with the aim of developing a strategic spatial plan for the city region.  An organisation has been set up to deal with the first phase of the process, which is to carry out three functional analyses and prepare a common vision...... in the area.   The municipalities acknowledge the articulation of the city region and the initiated planning process.  However, the municipalities might see the arena as means to lobby for infrastructure investments in Eastern Jutland, as it is doubtful whether the municipalities will feel encouraged to enter...... a process, which is aiming at increasing the national regulation within their territory.    The result might very well be that the discussion about future infrastructure investments is not linked to discussions about future urban development in Eastern Jutland.  These aspects raises serious questions about...

  9. Formation and support of prominence

    Forbes, T.G.

    1986-01-01

    A short introduction is given to the concepts discussed by the group on the formation and support of prominences. Only quiescent and long-lived active region prominences were considered, since transient prominence phenomena, such as sprays, surges, H alpha flare-loops, and coronal rain, are dynamically distinct from long-lived, prominences. Stable prominences (which are often referred to as filaments when seen against the disk) can be subdivided into three categories, namely active region prominences, quiescent prominences and polar crown prominences. The third category is closely related to the second since a quiescent prominence will eventually evolve into a polar crown prominence if it lasts long enough. The distinction between the first and second categories is not sharp either since intermediates exist here as well (Martin, 1973)

  10. New Office Software course format

    HR Department

    2010-01-01

    Always interested to anticipate your training needs, the Technical Training service is pleased to propose two new Office Software course formats : “Focus on... ” : On a monthly basis we will propose a theme such as “Sharepoint Collaboration Workspace” or “Word 2007” or “charts” etc. You will have to send us in advance your questions regarding the proposed topic and register for the course through our Training Catalogue. During the session, our trainer will answer all the questions received and participants will increase their knowledge thanks to the solutions discussed for everyone. The course will last two hours, from 09h00 to 11h00 - with open questions on the proposed topic at the end. “Office software Individual coaching”: If one or several particular topics cause you sleepless nights, you can get the help of our trainer who will come to your workplace for a multiple of 1-hour slots . All fields ...

  11. Accretion Processes in Star Formation

    Küffmeier, Michael

    for short-lived radionuclides that enrich the cloud as a result of supernova explosions of the massive stars allows us to analyze the distribution of the short-lived radionuclides around young forming stars. In contradiction to results from highly-idealized models, we find that the discrepancy in 26 Al...... that the accretion process of stars is heterogeneous in space, time and among different protostars. In some cases, disks form a few thousand years after stellar birth, whereas in other cases disk formation is suppressed due to efficient removal of angular momentum. Angular momentum is mainly transported outward...... with potentially observable fluctuations in the luminosity profile that are induced by variations in the accretion rate. Considering that gas inside protoplanetary disks is not fully ionized, I implemented a solver that accounts for nonideal MHD effects into a newly developed code framework called dispatch...

  12. String Formation Beyond Leading Colour

    Christiansen, Jesper R.

    2015-08-03

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading $N_C$ are allowed to influence the formation of confining potentials (strings). The multiplet structure of $SU(3)$ is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In $e^+e^-$collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in $pp$ collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive $1/N_C^2$ suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important $\\left(n_\\mathrm{charged})$ distribution but also with measured rates (and ra...

  13. Restucturing the Project Work Format

    Dupont, Søren

    2015-01-01

    The chapter is based on an evaluation of a pedagogical experiment at Roskilde University, the Antology Experiment. The objective of the experiment was to develop and expand the framework for project work through the production of anthologies compiled collectively by a number of project groups....... The novel aspects of the Anthology Experiment were most notably its magnitude and complexity. In this experiment the groups were totalling some 50 students who were working together. The experiment used a well-known publishing format from research, namely the anthology form, which usually focuses...... on a specific research topic and includes contributions from various researchers. In the Anthology Experiment, the project groups could be viewed as ‘research units’ that produce the contributions to the anthology. The complexity of the experiment offered challenges, both for students and supervisors...

  14. Price formation and market mechanisms

    Neff, T.L.

    1991-01-01

    World markets for nuclear fuel have changed greatly since the 1970s. In earlier days, firms specializing in mining, conversion, enrichment and fabrication negotiated directly with end users, primarily under long term contracts at specified prices. This old model is gone. Market structure has been transformed: traditional suppliers now compete with traders, some of whom can offer a much larger menu of products and terms than primary suppliers. Utilities act as traders, converters as brokers, brokers as traders, producers as buyers, and so on. De-enrichment, de-conversion, loans, swaps, interchanges and other new kinds of transactions have proliferated. These changes in market structure and market mechanisms have been accompanied by substantial changes in price formation, that is the process by which market price is set. Today, the level and direction of price are set in a trading dominated spot market environment, fuelled by inventory liquidation and Soviet and other non-traditional supply. (author)

  15. Complexity of formation in holography

    Chapman, Shira [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Marrochio, Hugo [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); Department of Physics & Astronomy and Guelph-Waterloo Physics Institute,University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Myers, Robert C. [Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada)

    2017-01-16

    It was recently conjectured that the quantum complexity of a holographic boundary state can be computed by evaluating the gravitational action on a bulk region known as the Wheeler-DeWitt patch. We apply this complexity=action duality to evaluate the ‘complexity of formation’ (DOI: 10.1103/PhysRevLett.116.191301; 10.1103/PhysRevD.93.086006), i.e. the additional complexity arising in preparing the entangled thermofield double state with two copies of the boundary CFT compared to preparing the individual vacuum states of the two copies. We find that for boundary dimensions d>2, the difference in the complexities grows linearly with the thermal entropy at high temperatures. For the special case d=2, the complexity of formation is a fixed constant, independent of the temperature. We compare these results to those found using the complexity=volume duality.

  16. Uranium price formation. Final report

    1977-10-01

    The modern uranium industry came into existence in 1946. Until 1966, its sole customer was the Atomic Energy Commission, whose needs for U 3 O 8 relative to industry capacity declined over the years. The development of the commercial market after 1965 coincided with a period of excess capacity and falling nominal and real prices. Gradually in 1973 and dramatically thereafter, market conditions changed and prices rose as utilities sought larger quantities of U 3 O 8 and longer term contracts. Questions about availability of long-run supplies were raised, given the known reserve base. The response of the supply of U 3 O 8 to incentives offered first by the AEC and later by the utilities in the context of new and developing market conventions is examined. The methodology used is microeconomic analysis, qualitatively applied to the history of price formation in the market. Because the study emphasizes the implications of the history of uranium price formation for forecasting supply response, the study presents many different kinds of data and evaluates their quality and appropriateness for forecasting. A simple, very-useful framework for analyzing the history of the market for U 3 O 8 was developed and used to describe supply responses in selected important periods of the industry's development. It is concluded that the response of supply of U 3 O 8 to rising prices or to expectations of demand growth has been impressively strong. The potential reserve inventory is large enough to meet the needs for nuclear power generation through the end of this century. The price necessary to induce producers to find and produce these reserves is uncertain, partly because of problems inherent in estimating long-run supply curves and partly because recent inflation has created major uncertainties about the cost of future supplies

  17. Thermal Behaviour of clay formations

    Tassoni, E.

    1985-01-01

    The programme carried out by ENEA to model the thermal-hydraulic-mechanical behaviour of the clay formations and to measure, in situ and in laboratory, the thermal properties of these rocks, is presented. An in situ heating experiment has been carried out in an open clay quarry in the area of Monterotondo, near Rome. The main goal of the experiment was to know the temperature field and the thermal effects caused by the high level radioactive waste disposed of in a clayey geological formation. The conclusions are as follows: - the thermal conduction codes are sufficiently accurate to forecast the temperature increases caused in the clay by the dissipation of the heat generated by high level radioactive waste; - the thermal conductivity deduced by means of the ''curve fitting'' method ranges from 0.015 to 0.017 W.cm -1 . 0 C -1 - the temperature variation associated with the transport of clay interstitial water caused by temperature gradient is negligible. A laboratory automated method has been designed to measure the thermal conductivity and diffusivity in clay samples. A review of experimental data concerning thermomechanical effects in rocks as well as results of thermal experiments performed at ISMES on clays are presented. Negative thermal dilation has been found both in the elastic and plastic range under constant stress. Thermoplastic deformation appears ten times greater than the thermoelastic one. A mathematical model is proposed in order to simulate the above and other effects that encompass thermal-elastic-plastic-pore water pressure response of clays at high temperature and effective pressure with undrained and transient drainage conditions. Implementation of the two versions into a finite element computer code is described

  18. Drill cuttings mount formation study

    Teh, Su Yean; Koh, Hock Lye

    2014-07-01

    Oil, Gas and Energy sector has been identified as an essential driving force in the Malaysian Economic Transformation Programs (ETP). Recently confirmed discovery of many offshore oil and gas deposits in Malaysian waters has ignited new confidence in this sector. However, this has also spurred intense interest on safeguarding the health and environment of coastal waters in Malaysia from adverse impact resulting from offshore oil and gas production operation. Offshore discharge of spent drilling mud and rock cuttings is the least expensive and simplest option to dispose of large volumes of drilling wastes. But this onsite offshore disposal may have adverse environmental impacts on the water column and the seabed. It may also pose occupational health hazards to the workers living in the offshore platforms. It is therefore important to model the transport and deposition of drilling mud and rock cuttings in the sea to enable proper assessment of their adverse impacts on the environment and the workers. Further, accumulation of drill particles on the seabed may impede proper operation of pipelines on the seabed. In this paper, we present an in-house application model TUNA-PT developed to cater to local oil and gas industry needs to simulate the dispersion and mount formation of drill cuttings by offshore oil and gas exploration and production platforms. Using available data on Malaysian coastal waters, simulation analyses project a pile formation on the seabed with a maximum height of about 1 m and pile radius of around 30 to 50 m. Simulated pile heights are not sensitive to the heights of release of the cuttings as the sensitivity has been mitigated by the depth of water.

  19. Engram Formation in Psychiatric Disorders

    Peter J. Gebicke-Haerter

    2014-05-01

    Full Text Available Environmental factors substantially influence beginning and progression of mental illness, reinforcing or reducing the consequences of genetic vulnerability. Often initiated by early traumatic events, engrams or memories are formed that may give rise to a slow and subtle progression of psychiatric disorders. The large delay between beginning and time of onset (diagnosis may be explained by efficient compensatory mechanisms observed in brain metabolism that use optional pathways in highly redundant molecular interactions.To this end, research has to deal with mechanisms of learning and long-term memory formation, which involves a epigenetic changes, b altered neuronal activities and c changes in neuron-glia communication. On the epigenetic level, apparently DNA-methylations are more stable than histone modifications, although both closely interact. Neuronal activities basically deliver digital information, which clearly can serve as basis for memory formation (LTP. However, research in this respect has long time neglected the importance of glia. They are more actively involved in the control of neuronal activities than thought before. They can both reinforce and inhibit neuronal activities by transducing neuronal information from frequency-encoded to amplitude and frequency-modulated calcium wave patterns spreading in the glial syncytium by use of gap junctions. In this way, they serve integrative functions. In conclusion, we are dealing with two concepts of encoding information that mutually control each other and synergize: a digital (neuronal and a wave-like (glial computing, forming neuron-glia functional units with inbuilt feedback loops to maintain balance of excitation and inhibition. To better understand mental illness, we have to gain more insight into the dynamics of adverse environmental impact on those cellular and molecular systems. This report summarizes existing knowledge and draws some outline about further research in molecular

  20. Heating tar sands formations while controlling pressure

    Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

    2010-01-12

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

  1. Radiogeochemical features of hydrothermal metasomatic formations

    Plyushchev, E.V.; Ryabova, L.A.; Shatov, V.V.

    1978-01-01

    Considered are the most general peculiarities of uranium and thorium distributions in hydrothermal-metasomatic formations of three levels of substance formation: 1) in hydrothermal minerals; 2) in natural associations of these minerals (in the altered rocks, metasomatites, ores, etc.); 3) ordened series of zonally and in stage conjugated hydrothermal-metasomatic formations. Statistically stable recurrence of natural combinations of hydrothermal-metasomatic formations points out conjugation of their formation in the directed evolution in the general hydrothermal process. Series of metasomatic formations, the initial members of which are potassium metasomatites, mostly result in accumulation up to industrial concentrations of radioactive elements in final members of these formations. Development of midlow-temperature propylitic alterations in highly radiative rocks causes the same accumulation

  2. Improving the Formatting Tools of CDS Invenio

    Caffaro, J; Pu Faltings, Pearl

    2006-01-01

    CDS Invenio is the web-based integrated digital library system developed at CERN. It is a strategical tool that supports the archival and open dissemination of documents produced by CERN researchers. This paper reports on my Master’s thesis work done on BibFormat, a module in CDS Invenio, which formats documents metadata. The goal of this project was to implement a completely new formatting module for CDS Invenio. In this report a strong emphasis is put on the user-centered design of the new BibFormat. The bibliographic formatting process and its requirements are discussed. The task analysis and its resulting interaction model are detailed. The document also shows the implemented user interface of BibFormat and gives the results of the user evaluation of this interface. Finally the results of a small usability study of the formats included in CDS Invenio are discussed.

  3. Fibril formation from pea protein and subsequent gel formation.

    Munialo, Claire Darizu; Martin, Anneke H; van der Linden, Erik; de Jongh, Harmen H J

    2014-03-19

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of β-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels.

  4. Magnetic Assisted Colloidal Pattern Formation

    Yang, Ye

    Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of

  5. Benzene formation in electronic cigarettes.

    James F Pankow

    Full Text Available The heating of the fluids used in electronic cigarettes ("e-cigarettes" used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen from e-cigarette fluids containing propylene glycol (PG, glycerol (GL, benzoic acid, the flavor chemical benzaldehyde, and nicotine.Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice, and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG and glycerol (GL, and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  6. Method of developing thick sloping coal formations

    Bragintsev, V F; Mashkovtsev, I L; Semenov, V S; Zykov, V N

    1980-04-25

    A method is patented for developing thick sloping coal formations in 3 inclined layers. It includes conducting developmental operations for each of the layers until one begins the last one and extraction of the layers. In order to improve effectivess and extraction operation safety one first carried out preliminary development of a formation in thin strips beneath protected objects when extracting formation which contain alot of gas. Then one removes the gas of a formation through boreholes that have been drilled into the formation from the indicated workings. Then one works the upper layer in thin strips in a sequence from the roof of the formation to the floor of the upper layer. The one strengthens roof rock of the formation by pumping in a quickly hardening solution into the boreholes which have been drilled into the roof of the formation after processing the upper layer. The middle layer is worked in thin strips in the sequence from the roof to the ground of the middle layer, then the lower layer of the formation is strengthened by pumping in quickly hardening solution into the formation along degasified boreholes and it is worked in thin strips in sequence from the ground of the lower to its roof. Workings are shaped respectively for the middle and lower layers by deepening workings of the upper and middle layers. The layers are worked respectively after finishing displacement of the roof in front of the extraction face of each subsequent extraction of a layer in alternating fashion.

  7. String formation beyond leading colour

    Christiansen, Jesper R. [Department of Astronomy and Theoretical Physics, Lund University,Sölvegatan 14, Lund (Sweden); Theoretical Physics, CERN,CH-1211, Geneva 23 (Switzerland); Skands, Peter Z. [Theoretical Physics, CERN,CH-1211, Geneva 23 (Switzerland); School of Physics and Astronomy, Monash University,VIC-3800 (Australia)

    2015-08-03

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N{sub C} are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for “baryonic” configurations (e.g., two colours can combine coherently to form an anticolour). In e{sup +}e{sup −}collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/N{sub C}{sup 2} suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important 〈p{sub ⊥}〉(n{sub charged}) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p{sub ⊥} spectra remains challenging to explain.

  8. Galaxy formation and physical bias

    Cen, Renyue; Ostriker, Jeremiah P.

    1992-01-01

    We have supplemented our code, which computes the evolution of the physical state of a representative piece of the universe to include, not only the dynamics of dark matter (with a standard PM code), and the hydrodynamics of the gaseous component (including detailed collisional and radiative processes), but also galaxy formation on a heuristic but plausible basis. If, within a cell the gas is Jeans' unstable, collapsing, and cooling rapidly, it is transformed to galaxy subunits, which are then followed with a collisionless code. After grouping them into galaxies, we estimate the relative distributions of galaxies and dark matter and the relative velocities of galaxies and dark matter. In a large scale CDM run of 80/h Mpc size with 8 x 10 exp 6 cells and dark matter particles, we find that physical bias b is on the 8/h Mpc scale is about 1.6 and increases towards smaller scales, and that velocity bias is about 0.8 on the same scale. The comparable HDM simulation is highly biased with b = 2.7 on the 8/h Mpc scale. Implications of these results are discussed in the light of the COBE observations which provide an accurate normalization for the initial power spectrum. CDM can be ruled out on the basis of too large a predicted small scale velocity dispersion at greater than 95 percent confidence level.

  9. Stages of neuronal network formation

    Woiterski, Lydia; Käs, Josef A; Claudepierre, Thomas; Luxenhofer, Robert; Jordan, Rainer

    2013-01-01

    Graph theoretical approaches have become a powerful tool for investigating the architecture and dynamics of complex networks. The topology of network graphs revealed small-world properties for very different real systems among these neuronal networks. In this study, we observed the early development of mouse retinal ganglion cell (RGC) networks in vitro using time-lapse video microscopy. By means of a time-resolved graph theoretical analysis of the connectivity, shortest path length and the edge length, we were able to discover the different stages during the network formation. Starting from single cells, at the first stage neurons connected to each other ending up in a network with maximum complexity. In the further course, we observed a simplification of the network which manifested in a change of relevant network parameters such as the minimization of the path length. Moreover, we found that RGC networks self-organized as small-world networks at both stages; however, the optimization occurred only in the second stage. (paper)

  10. Dark Energy and Structure Formation

    Singh, Anupam

    2010-01-01

    We study the gravitational dynamics of dark energy configurations. We report on the time evolution of the dark energy field configurations as well as the time evolution of the energy density to demonstrate the gravitational collapse of dark energy field configurations. We live in a Universe which is dominated by Dark Energy. According to current estimates about 75% of the Energy Density is in the form of Dark Energy. Thus when we consider gravitational dynamics and Structure Formation we expect Dark Energy to play an important role. The most promising candidate for dark energy is the energy density of fields in curved space-time. It therefore become a pressing need to understand the gravitational dynamics of dark energy field configurations. We develop and describe the formalism to study the gravitational collapse of fields given any general potential for the fields. We apply this formalism to models of dark energy motivated by particle physics considerations. We solve the resulting evolution equations which determine the time evolution of field configurations as well as the dynamics of space-time. Our results show that gravitational collapse of dark energy field configurations occurs and must be considered in any complete picture of our universe.

  11. Chloride Transport in Heterogeneous Formation

    Mukherjee, A.; Holt, R. M.

    2017-12-01

    The chloride mass balance (CMB) is a commonly-used method for estimating groundwater recharge. Observations of the vertical distribution of pore-water chloride are related to the groundwater infiltration rates (i.e. recharge rates). In CMB method, the chloride distribution is attributed mainly to the assumption of one dimensional piston flow. In many places, however, the vertical distribution of chloride will be influenced by heterogeneity, leading to horizontal movement of infiltrating waters. The impact of heterogeneity will be particularly important when recharge is locally focused. When recharge is focused in an area, horizontal movement of chloride-bearing waters, coupled with upward movement driven by evapotranspiration, may lead to chloride bulges that could be misinterpreted if the CMB method is used to estimate recharge. We numerically simulate chloride transport and evaluate the validity of the CMB method in highly heterogeneous systems. This simulation is conducted for the unsaturated zone of Ogallala, Antlers, and Gatuna (OAG) formations in Andrews County, Texas. A two dimensional finite element model will show the movement of chloride through heterogeneous systems. We expect to see chloride bulges not only close to the surface but also at depths characterized by horizontal or upward movement. A comparative study of focused recharge estimates in this study with available recharge data will be presented.

  12. New Office Software course format!

    HR Department

    Always keen to anticipate your  training needs, the Technical Training service is pleased to propose two new Office Software course formats: “Focus on... ”:  On a monthly basis we will propose a theme such as “Sharepoint Collaboration Workspace” or “Word 2007” or “charts”, etc.  You will be invited to send us in advance your questions regarding the proposed topic and register  for the course through our Training Catalogue. During the session, our trainer will answer all the questions received and participants will increase their knowledge thanks to the solutions discussed for everyone. The course will last two hours, from 9-00 to 11-00 a.m. - with open questions on the proposed topic at the end.   “Office software Individual coaching”: If one or more specific topics are causing you sleepless nights, you can get the help of our trainer who will ...

  13. New Office Software course format!

    HR Department

    2009-01-01

    Always keen to anticipate your  training needs, the Technical Training service is pleased to propose two new Office Software course formats: “Focus on... ”:  On a monthly basis we will propose a theme such as “Sharepoint Collaboration Workspace” or “Word 2007” or “charts”, etc.  You will be invited to send us in advance your questions regarding the proposed topic and register  for the course through our Training Catalogue. During the session, our trainer will answer all the questions received and participants will increase their knowledge thanks to the solutions discussed for everyone. The course will last two hours, from 9-00 to 11-00 a.m. - with open questions on the proposed topic at the end.   “Office software Individual coaching”: If one or more specific topics are causing you sleepless nights, you can get the help of our trainer who will ...

  14. Formation of submarine gas hydrates

    Soloviev, V.; Ginsburg, G.D. (Reserch Institute of Geology and Mineral Resources of the Ocean ' ' VNII Okeangeologia' ' , St. Petersburg (Russian Federation))

    1994-03-01

    Submarine gas hydrates have been discoverd in the course of deep-sea drilling (DSDP and ODP) and bottom sampling in many offshore regions. This paper reports on expeditions carried out in the Black, Caspian and Okhotsk Seas. Gas hydrate accumulations were discovered and investigated in all these areas. The data and an analysis of the results of the deep-sea drilling programme suggest that the infiltration of gas-bearing fluids is a necessary condition for gas hydrate accumulation. This is confirmed by geological observations at three scale levels. Firstly, hydrates in cores are usually associated with comparatively coarse-grained, permeable sediments as well as voids and fractures. Secondly, hydrate accumulations are controlled by permeable geological structures, i.e. faults, diapirs, mud volcanos as well as layered sequences. Thirdly, in the worldwide scale, hydrate accumulations are characteristic of continental slopes and rises and intra-continental seas where submarine seepages also are widespread. Both biogenic and catagenic gas may occur, and the gas sources may be located at various distances from the accumulation. Gas hydrates presumably originate from water-dissolved gas. The possibility of a transition from dissolved gas into hydrate is confirmed by experimental data. Shallow gas hydrate accumulations associated with gas-bearing fluid plumes are the most convenient features for the study of submarine hydrate formation in general. These accumulations are known from the Black, Caspian and Okhotsk Seas, the Gulf of Mexico and off northern California. (au) (24 refs.)

  15. STAR FORMATION IN DENSE CLUSTERS

    Myers, Philip C.

    2011-01-01

    A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while the surrounding clump gas accretes as a power of protostar mass. Short accretion flows resemble Shu accretion and make low-mass stars. Long flows resemble reduced Bondi accretion and make massive stars. Accretion stops due to environmental processes of dynamical ejection, gravitational competition, and gas dispersal by stellar feedback, independent of initial core structure. The model matches the field star initial mass function (IMF) from 0.01 to more than 10 solar masses. The core accretion rate and the mean accretion duration set the peak of the IMF, independent of the local Jeans mass. Massive protostars require the longest accretion durations, up to 0.5 Myr. The maximum protostar luminosity in a cluster indicates the mass and age of its oldest protostar. The distribution of protostar luminosities matches those in active star-forming regions if protostars have a constant birthrate but not if their births are coeval. For constant birthrate, the ratio of young stellar objects to protostars indicates the star-forming age of a cluster, typically ∼1 Myr. The protostar accretion luminosity is typically less than its steady spherical value by a factor of ∼2, consistent with models of episodic disk accretion.

  16. Shock formation within sonoluminescence bubbles

    Vuong, V.Q.; Szeri, A.J.; Young, D.A.

    1999-01-01

    A strong case has been made by several authors that sharp, spherically symmetric shocks converging on the center of a spherical bubble driven by a strong acoustic field give rise to rapid compression and heating that produces the brief flash of light known as sonoluminescence. The formation of such shocks is considered. It is found that, although at the main collapse the bubble wall does indeed launch an inwardly-traveling compression wave, and although the subsequent reflection of the wave at the bubble center produces a very rapid temperature peak, the wave is prevented from steepening into a sharp shock by an adverse gradient in the sound speed caused by heat transfer. It is shown that the mathematical characteristics of the flow can be prevented from accumulating into a shock front by this adverse sound speed gradient. A range of results is presented for a variety of bubble ambient radii and sound field amplitudes suggested by experiments. The time scale of the peak temperature in the bubble is set by the dynamics of the compression wave: this is typically in the range 100 - 300 ps (FWHM) in concert with recent measurements of the sonoluminescence pulse width. copyright 1999 American Institute of Physics

  17. Spheromak formation studies in SSPX

    Hill, D.N.; Bulmer, R.H.; Cohen, B.L.; Hooper, E.B.; LoDestro, L.L.; Mattor, N.; McLean, H.S.; Moller, J.; Pearlstein, L.D.; Ryutov, D.D.; Stallard, B.W.; Wood, R.D.; Woodruff, S.; Holcomb, C.T.; Jarboe, T.; Sovinec, C.R.; Wang, Z.; Wurden, G.

    2000-01-01

    We present results from the Sustained Spheromak Physics Experiment (SSPX) at LLNL, which has been built to study energy confinement in spheromak plasmas sustained for up to 2 ms by coaxial DC helicity injection. Peak toroidal currents as high as 600kA have been obtained in the 1m dia. (0.23m minor radius) device using injection currents between 200-400kA; these currents generate edge poloidal fields in the range of 0.2-0.4T. The internal field and current profiles are inferred from edge field measurements using the CORSICA code. Density and impurity control is obtained using baking, glow discharge cleansing, and titanium gettering, after which long plasma decay times (τ (ge) 1.5ms) are observed and impurity radiation losses are reduced from ∼50% to e (0)∼120eV and β e ∼7%. Edge field measurements show the presence of n=1 modes during the formation phase, as has been observed in other spheromaks. This mode dies away during sustainment and decay so that edge fluctuation levels as low as 1% have been measured. These results are compared with numerical simulations using the NIMROD code

  18. SPMHD simulations of structure formation

    Barnes, David J.; On, Alvina Y. L.; Wu, Kinwah; Kawata, Daisuke

    2018-05-01

    The intracluster medium of galaxy clusters is permeated by μ {G} magnetic fields. Observations with current and future facilities have the potential to illuminate the role of these magnetic fields play in the astrophysical processes of galaxy clusters. To obtain a greater understanding of how the initial seed fields evolve to the magnetic fields in the intracluster medium requires magnetohydrodynamic simulations. We critically assess the current smoothed particle magnetohydrodynamic (SPMHD) schemes, especially highlighting the impact of a hyperbolic divergence cleaning scheme and artificial resistivity switch on the magnetic field evolution in cosmological simulations of the formation of a galaxy cluster using the N-body/SPMHD code GCMHD++. The impact and performance of the cleaning scheme and two different schemes for the artificial resistivity switch is demonstrated via idealized test cases and cosmological simulations. We demonstrate that the hyperbolic divergence cleaning scheme is effective at suppressing the growth of the numerical divergence error of the magnetic field and should be applied to any SPMHD simulation. Although the artificial resistivity is important in the strong field regime, it can suppress the growth of the magnetic field in the weak field regime, such as galaxy clusters. With sufficient resolution, simulations with divergence cleaning can reproduce observed magnetic fields. We conclude that the cleaning scheme alone is sufficient for galaxy cluster simulations, but our results indicate that the SPMHD scheme must be carefully chosen depending on the regime of the magnetic field.

  19. Decentralized Control for Scalable Quadcopter Formations

    Qasim Ali

    2016-01-01

    Full Text Available An innovative framework has been developed for teamwork of two quadcopter formations, each having its specified formation geometry, assigned task, and matching control scheme. Position control for quadcopters in one of the formations has been implemented through a Linear Quadratic Regulator Proportional Integral (LQR PI control scheme based on explicit model following scheme. Quadcopters in the other formation are controlled through LQR PI servomechanism control scheme. These two control schemes are compared in terms of their performance and control effort. Both formations are commanded by respective ground stations through virtual leaders. Quadcopters in formations are able to track desired trajectories as well as hovering at desired points for selected time duration. In case of communication loss between ground station and any of the quadcopters, the neighboring quadcopter provides the command data, received from the ground station, to the affected unit. Proposed control schemes have been validated through extensive simulations using MATLAB®/Simulink® that provided favorable results.

  20. Autonomous Formations of Multi-Agent Systems

    Dhali, Sanjana; Joshi, Suresh M.

    2013-01-01

    Autonomous formation control of multi-agent dynamic systems has a number of applications that include ground-based and aerial robots and satellite formations. For air vehicles, formation flight ("flocking") has the potential to significantly increase airspace utilization as well as fuel efficiency. This presentation addresses two main problems in multi-agent formations: optimal role assignment to minimize the total cost (e.g., combined distance traveled by all agents); and maintaining formation geometry during flock motion. The Kuhn-Munkres ("Hungarian") algorithm is used for optimal assignment, and consensus-based leader-follower type control architecture is used to maintain formation shape despite the leader s independent movements. The methods are demonstrated by animated simulations.

  1. Reflections about the mathematics teachers' formation

    Maria José de Freitas Mendes

    2010-06-01

    Full Text Available This paper brings some reflections about the formation of the math teacher that made part of my marsters paper and that aimed to investigate the process of formation of the math teacher. The focus of this study incided at the contributions of teaching practice in the teacher's formation above the new paradigms of formation, as a professional development and as a reflexive teacher. These reflections, from the learning and teaching process and from the meaning of form a teacher analyse the crisis and the restructuration of the teacher's formation and conclude being necessary that in the graduation courses there's a character more practice to the pedagogical formation, making possible for the future teacher to develop attitudes of autonomy, reflexion and investigation

  2. Formation temperatures of thermogenic and biogenic methane

    Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, Anna M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

    2014-01-01

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  3. Habit formation, work ethics, and technological progress

    Faria, João Ricardo; León-Ledesma, Miguel A.

    2002-01-01

    Work ethics affects labor supply. This idea is modeled assuming that work is habit forming. This paper introduces working habits in a neoclassical growth model and compares its outcomes with a model without habit formation. In addition, it analyzes the impact of different forms of technical progress. The findings are that i) labor supply in the habit formation case is higher than in the neoclassical case; ii) unlike in the neoclassical case, labor supply in the presence of habit formation wil...

  4. Theoretical Aspects of Enterprise Business Strategy Formation

    Valentinavičius, Stasys

    2009-01-01

    The paper presents interpretations of business strategy concept and analyses strategy planning and formation, models. The concept of business strategy is revised and formulated considering various authors approaches. Analysis of business strategy formation process – steps of development and management, selection of strategy type – is based on presented strategy planning models. The aspects of enterprise business and investment strategy formation, coordination and valuation are analysed. The s...

  5. Formation and behaviour of organic iodine

    Zilliacus, R.; Koukkar, P.; Karjunen, T.; Sjoevall, H.

    2002-01-01

    The report presents experimental studies on the formation of organic iodine in severe reactor accidents. The analyses were performed to evaluate the amount of alkaline chemical needed for effective pH control of containment water during the accidents. The formation of organic iodine in solutions used in the filtered venting system and the absorption of iodine compounds in the solutions were studied. Experiments for the formation of organic iodine on painted surfaces were also performed. (au)

  6. Transient Exciplex Formation Electron Transfer Mechanism

    Michael G. Kuzmin; Irina V. Soboleva; Elena V. Dolotova

    2011-01-01

    Transient exciplex formation mechanism of excited-state electron transfer reactions is analyzed in terms of experimental data on thermodynamics and kinetics of exciplex formation and decay. Experimental profiles of free energy, enthalpy, and entropy for transient exciplex formation and decay are considered for several electron transfer reactions in various solvents. Strong electronic coupling in contact pairs of reactants causes substantial decrease of activation energy relative to that for c...

  7. Negative ion formation and neutralization processes, (1)

    Sugiura, Toshio

    1982-01-01

    This review has been made preliminary for the purpose of contribute to the plasma heating by ''negative ion based neutral beam injection'' in the magnetic confinement fusion reactor. A compilation includes the survey of the general processes of negative ion formation, the data of the cross section of H - ion formation and the neutralization of H - ion, and some of new processes of H - ion formation. The data of cross section are mainly experimental, but partly include the results of theoretical calculation. (author)

  8. Mechanism of anticlinal trap formation

    Kuliev, G.G; Kasimova, S.M; Kulieva, G.Z.

    2002-01-01

    Full text: Geo dynamic development of sedimentary basin in accompanied in different stages by significant changes of stressed states. These changes can cover the upper layers as well as deep inner layers of geological stack. In certain levels, called critical level, in consequence of exhausting the feasibility of slow constant deformation, change of regular structures Equilibrium State and folding formation may occur. In total with horizontal component of geo static pressure and tectonic stress, in both cases these compressive loads may be enough to form folding by means of regular structure Equilibrium State instability loss and change to more stable Equilibrium State with curved structure. In this report there are the results of investigation of given problem within non-classical linearized 3D theoretical geomechanical model. Symmetric and asymmetric forms of change to more stable Equilibrium State when modeling deformed medium in kind of an isotropic and anisotropic material, in case of small elastic deformation were investigated. So, results permit us to conclude that only owing to submersion, different forms of structural curvature may occur in geological stack and that parameters of these structural form-changing are considered more accurate within non-classical linearized 3D geo dynamical model.Analogous results were obtained in case of compressive stress occurrence in consequence of density differentiation of rocks. From the obtains results it follows that Equilibrium State of half-plane in irregular compression proves to be unstable when assigning on free half-plane surface dead as well as tracking loads. The increase of intensity value of different surface loads exerts contrary influence on values of critical loads of stability loss depending on modeling of their character of influence. So, the increase of intensity of dead surface loads leads to decrease, but increase of tracking surface loads leads to increase of equilibrium state loss critical force

  9. STAR FORMATION IN 30 DORADUS

    De Marchi, Guido; Spezzi, Loredana; Sirianni, Marco; Andersen, Morten; Paresce, Francesco; Panagia, Nino; Mutchler, Max; Whitmore, Bradley C.; Bond, Howard; Beccari, Giacomo; Balick, Bruce; Dopita, Michael A.; Frogel, Jay A.; Calzetti, Daniela; Marcella Carollo, C.; Disney, Michael J.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.

    2011-01-01

    Using observations obtained with the Wide-Field Camera 3 on board the Hubble Space Telescope, we have studied the properties of the stellar populations in the central regions of 30 Dor in the Large Magellanic Cloud. The observations clearly reveal the presence of considerable differential extinction across the field. We characterize and quantify this effect using young massive main-sequence stars to derive a statistical reddening correction for most objects in the field. We then search for pre-main-sequence (PMS) stars by looking for objects with a strong (>4σ) Hα excess emission and find about 1150 of them over the entire field. Comparison of their location in the Hertzsprung-Russell diagram with theoretical PMS evolutionary tracks for the appropriate metallicity reveals that about one-third of these objects are younger than ∼4 Myr, compatible with the age of the massive stars in the central ionizing cluster R 136, whereas the rest have ages up to ∼30 Myr, with a median age of ∼12 Myr. This indicates that star formation has proceeded over an extended period of time, although we cannot discriminate between an extended episode and a series of short and frequent bursts that are not resolved in time. While the younger PMS population preferentially occupies the central regions of the cluster, older PMS objects are more uniformly distributed across the field and are remarkably few at the very center of the cluster. We attribute this latter effect to photo-evaporation of the older circumstellar disks caused by the massive ionizing members of R 136.

  10. Processes and problems in secondary star formation

    Klein, R.I.; Whitaker, R.W.; Sandford, M.T. II.

    1984-03-01

    Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of the observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on colliding inter-cloud gas flows leading to non-linear inhomogeneous cloud structures in an intially smooth cloud. This clumpy morphology has important consequences for secondary formation. The triggering processes of supernovae, stellar winds, and H II regions are discussed with emphasis on the consequences for radiation driven implosion as a promising secondary star formation mechanism. Detailed two-dimensional, radiation-hydrodynamic calculations of radiation driven implosion are discussed. This mechanism is shown to be highly efficient in synchronizing the formation of new stars in congruent to 1-3 x 10 4 years and could account for the recent evidence for new massive star formation in several UCHII regions. It is concluded that, while no single theory adequately explains the variety of star formation observed, a uniform description of star formation is likely to involve several secondary processes. Advances in the theory of star formation will require multiple dimensional calculations of coupled processes. The important non-linear interactions include hydrodynamics, radiation transport, and magnetic fields

  11. Processes and problems in secondary star formation

    Klein, R.I.; Whitaker, R.W.; Sandford, M.T. II

    1985-01-01

    Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on colliding intercloud gas flows leading to nonlinear inhomogeneous cloud structures in an initially smooth cloud. This clumpy morphology has important consequences for secondary formation. The triggering processes of supernovae, stellar winds, and H II regions are discussed with emphasis on the consequences for radiation-driven implosion as a promising secondary star formation mechanism. Detailed two-dimensional, radiation-hydrodynamic calculations of radiation-driven implosion are discussed. This mechanism is shown to be highly efficient in synchronizing the formation of new stars in -- 1-3 x 10/sup 4/ yr and could account for the recent evidence for new massive star formation in several ultracompact H II regions. It is concluded that, while no single theory adequately explains the variety of star formation observed, a uniform description of star formation is likely to involve several secondary processes. Advances in the theory of star formation will require multi-dimensional calculations of coupled processes. Important nonlinear interactions include hydrodynamics, radiation transport, and magnetic fields

  12. Formation of the First Stars and Blackholes

    Yoshida, Naoki

    2018-05-01

    Cosmic reionization is thought to be initiated by the first generation of stars and blackholes. We review recent progress in theoretical studies of early structure formation. Cosmic structure formation is driven by gravitational instability of primeval density fluctuations left over from Big Bang. At early epochs, there are baryonic streaming motions with significant relative velocity with respect to dark matter. The formation of primordial gas clouds is typically delayed by the streaming motions, but then physical conditions for the so-called direct collapse blackhole formation are realized in proto-galactic halos. We present a promising model in which intermediate mass blackholes are formed as early as z = 30.

  13. The NeXus data format

    Könnecke, Mark; Akeroyd, Frederick A.; Osborn, Raymond; Peterson, Peter F.; Richter, Tobias; Suzuki, Jiro; Watts, Benjamin; Wintersberger, Eugen; Wuttke, Joachim; Bernstein, Herbert J.; Brewster, Aaron S.; Campbell, Stuart I.; Clausen, Björn; Cottrell, Stephen; Hoffmann, Jens Uwe

    2015-01-01

    NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamlin...

  14. An anti vimentin antibody promotes tube formation

    Jørgensen, Mathias Lindh; Møller, Carina Kjeldahl; Rasmussen, Lasse

    2017-01-01

    antibody technology, promotes tube formation of endothelial cells in a 2D matrigel assay. By binding vimentin, the antibody increases the tube formation by 21% after 5 hours of incubation. Addition of the antibody directly to cultured endothelial cells does not influence endothelial cell migration...... or proliferation. The enhanced tube formation can be seen for up to 10 hours where after the effect decreases. It is shown that the antibody-binding site is located on the coil 2 domain of vimentin. To our knowledge this is the first study that demonstrates an enhanced tube formation by binding vimentin in a 2D...

  15. Heating systems for heating subsurface formations

    Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  16. Heating tar sands formations to visbreaking temperatures

    Karanikas, John Michael [Houston, TX; Colmenares, Tulio Rafael [Houston, TX; Zhang, Etuan [Houston, TX; Marino, Marian [Houston, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Beer, Gary Lee [Houston, TX; Dombrowski, Robert James [Houston, TX; Jaiswal, Namit [Houston, TX

    2009-12-22

    Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

  17. Towards the Rosetta Stone of planet formation

    Schmidt T.O.B.

    2011-02-01

    Full Text Available Transiting exoplanets (TEPs observed just ~10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs, the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young or accretion growth (being smaller when young. We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.

  18. New Particle Formation Study Final Campaign Report

    Smith, JN; McMurry, PH [University of Minnesota

    2015-01-01

    The scientific foci of the New Particle Formation Study were the formation and evolution of atmospheric aerosols and the impacts of newly formed particles on cloud processes. Specifically, we planned to: (1) to identify the species and mechanisms responsible for the initial steps of new particle formation, i.e., the formation of thermodynamically stable clusters; (2) investigate the role of acid-base chemistry in new particle growth through measurements of ammonia and amines as well as organic and inorganic acids in both atmospheric nanoparticles and the gas phase; (3) investigate the contribution of other surface area or volume-controlled processes to nanoparticle formation and growth; (4) create a comprehensive dataset related to new particle formation and growth that can be used as input for our own thermodynamic models as well as the modeling efforts by our Department of Energy (DOE) Aerosol Life Cycle working group collaborators; (5) characterize the increase of the number and activity of cloud condensation nuclei (CCN) due to particle formation and growth; (6) determine the regional extent of new particle formation to address the role that atmospheric transport plays in determining the impacts, if any, of new particle formation on cloud number and properties.

  19. Probes of Cosmic Star Formation History

    I summarize X-ray diagnostic studies of cosmic star formation history in terms of evolutionary schemes for X-ray binary evolution in normal galaxies with evolving star formation. Deep X-ray imaging studies by Chandra and XMM-Newton are now beginning to constrain both the X-ray luminosity evolution of galaxies and the ...

  20. Network Formation under the Threat of Disruption

    Hoyer, B.

    2013-01-01

    The studies in this thesis are focused on the impact the presence of a network disruptor has on network formation models. In particular, we build two theoretical models to study the effect of network disruption on network formation and test the effect network disruption has on equilibrium selection

  1. Combinations of partners’ joint venture formation motives

    Klijn, E.; Reuer, J.J.; Buckley, P.J.; Glaister, K.W.

    2011-01-01

    Purpose – Prior research on joint venture (JV) formation often examines a single focal firm and assumes it has a single motive for collaboration. This study seeks to investigate how formation motives of partner firms are symmetrically coupled. It considers motives in the context of different

  2. General certification procedure of formation organizations

    Int. At. Energy Agency, Wien

    2002-01-01

    This document presents the procedure dealing with the certification of formation organizations dispensing the formation and the risks prevention to the personnel of A or B category in nuclear facilities. This certification proves the organization ability to satisfy the ''F'' specification of the CEFRI. (A.L.B.)

  3. Problems of Kazakh Literary Criticism Formation

    Zhandos Smagulov

    2013-01-01

    Full Text Available Тhe article is concerned with the problem of scientific research of Kazakh literature formation in national science. Kazakh literature, having long history of formation is classified by periods. Besides, the article thoroughly considers the principles of the study of methodology, theory, history of spiritual heritage in Kazakh literary criticism

  4. The early ISM and galaxy formation

    White, Simon D. M.

    1990-01-01

    Current ideas about galaxy formation are reviewed, with particular attention to when and how it occurred, and what it might have looked like. It is argued that galaxy formation is more recent than originally predicted. Suggestions are presented as to how current observations of distant objects may be interpreted within the cold dark matter theory for the origin of structure.

  5. 25 CFR 82.6 - Petition format.

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Petition format. 82.6 Section 82.6 Indians BUREAU OF... REORGANIZED UNDER FEDERAL STATUTE AND OTHER ORGANIZED TRIBES § 82.6 Petition format. Petitions may consist of... of a petition must set forth at least a summary of the objectives of the petitioners and must show...

  6. A Decentralized Approach to Formation Flight Routing

    Visser, H.G.; Lopes dos Santos, Bruno F.; Verhagen, C.M.A.

    2016-01-01

    This paper describes the development of an optimization-based cooperative planning system for the efficient routing and scheduling of flight formations. This study considers the use of formation flight as a means to reduce the overall fuel consumption of civil aviation in long-haul operations. It

  7. Unit Monitors Manchester-Format Data Buses

    Amador, Jose J.

    1994-01-01

    Circuit card converts data signals into convenient hexadecimal form for troubleshooting. Bus-monitoring unit converts data signals from Manchester II format used on data bus into hexadecimal format. Monitoring circuit causes hexadecimal words to display on video terminal, where test engineer compares them with hexadecimal records for troubleshooting. Circuit monitors one bus or two buses simultaneously.

  8. Distributed formation control for autonomous robots

    Garcia de Marina Peinado, Hector Jesús

    2016-01-01

    This thesis addresses several theoretical and practical problems related to formation-control of autonomous robots. Formation-control aims to simultaneously accomplish the tasks of forming a desired shape by the robots and controlling their coordinated collective motion. This kind of robot

  9. Spur Reaction Model of Positronium Formation

    Mogensen, O. E.

    1974-01-01

    A new model of positronium (Ps) formation is proposed. Positronium is assumed to be formed by a reaction between a positron and an electron in the positron spur. Ps formation must compete with electron‐ion recombination and electron or positron reactions with solvent molecules and scavenger...

  10. Hydrocarbon formation mechanism during uranium monocarbide hydrolysis

    Ermolaev, M.I.; Tishchenko, G.V.

    1979-01-01

    The hydrolysis of uranium monocarbide in oxidative media and in the presence of excessive hydrogen in statu nascendi has been investigated. It was found that oxydants promote the formation of elementary carbon, while in the presence of hydrogen the yield of light C-C hydrocarbons increases. EPR data confirm the radical mechanism of hydrocarbons formation during the decomposition of uranium monocarbide

  11. Formation and evolution of compact binaries

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  12. Enhancing the Lecture: Revitalizing the Traditional Format.

    Bonwell, Charles C.

    1996-01-01

    The traditional lecture format of college courses can be enhanced by including active learning designed to further course goals of learning knowledge, developing skills, or fostering attitudes. Techniques suggested include using pauses, short writing periods, think-pair-share activities, formative quizzes, lecture summaries, and several assessment…

  13. Stone Formation in the Infected Pediatric Enterocystoplasty

    R.B. Mathoera (Rejiv)

    2003-01-01

    markdownabstract__Abstract__ Proteus mirabilis is one of the most frequent bacterial agents that can induce infection stone formation by urease production. In recent years the influence of Proteus mirabilis on stone formation in enterocystoplasties has been primarily related to the presence of

  14. Computer-based feedback in formative assessment

    van der Kleij, Fabienne

    2013-01-01

    Formative assessment concerns any assessment that provides feedback that is intended to support learning and can be used by teachers and/or students. Computers could offer a solution to overcoming obstacles encountered in implementing formative assessment. For example, computer-based assessments

  15. Harnessing Collaborative Annotations on Online Formative Assessments

    Lin, Jian-Wei; Lai, Yuan-Cheng

    2013-01-01

    This paper harnesses collaborative annotations by students as learning feedback on online formative assessments to improve the learning achievements of students. Through the developed Web platform, students can conduct formative assessments, collaboratively annotate, and review historical records in a convenient way, while teachers can generate…

  16. Cellular chain formation in Escherichia coli biofilms

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    ; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  17. Structure of fructo-oligosaccharides from leaves and stem of Agave tequilana Weber, var. azul.

    Praznik, Werner; Löppert, Renate; Cruz Rubio, Josè M; Zangger, Klaus; Huber, Anton

    2013-11-15

    Fructo-oligosaccharides (FOSs) of a six year old agave plant variety, Agave tequilana, were isolated and fractionated by 2D preparative chromatography (SEC and rpHPLC). Structural analyses of different FOS-fractions were performed by reductive methylation analysis connected to GC/FID identification and NMR-analysis. FOSs from leaves (d.p. 3-8) contain single α-d-Glcp residues as well in terminal as internal position, however (2→1)-linked β-d-Fruf residues only. FOSs from stem, however, contain as well (2→1)- and (2→6)-linked β-d-Fruf residues with branched oligomeric repeating units. These characteristics indicate an enzymatically catalyzed metabolic regulation for the biosynthesis and transformation of fructans in A. tequilana which strongly depends on location and transport activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. A proposed chemical structure for fructans from blue agave plant (Tequilana Weber var. azul

    Guillermo Toriz

    2007-01-01

    Full Text Available Se propone una estructura química para las fructanas de agave Tequilana con base en los resultados combinados de las técnicas de permetilación y ruptura reductiva acopladas a cromatografía gas-líquido asi como también a cromatografía de exclusión de tamaños/dispersión de luz.

  19. APRESENTAÇÃO (Um pálido ponto azul

    Os Editores da Prometeus

    2011-05-01

    Full Text Available Em meados de abril deste ano tivemos a notícia (cf.http://voyager.jpl.nasa.gov/mission/index.html de que as naves Voyager 1 e 2, lançadasem 1977, estão nos limites da heliosfera e a ponto de penetrarem no espaço interestelar.Essa informação nos traz à memória Carl Sagan (1934-1996, cientista e astrônomonorte-americano que se dedicou não só à docência (foi professor de astronomia eciências espaciais na Universidade de Cornell e professor visitante no Laboratório dePropulsão a Jato do Insittuto de Tecnologia da Califórnia e à exploração espacial(consultor da NASA desde os anos 50, tomou parte do Projeto Apollo, chefiou osprojetos Mariner e Viking, e participou das missões Voyager e Galileu, mas também seconsagrou à divulgação científica, através de uma série de livros e programastelevisivos, entre os quais se destaca a série (e o livro Cosmos.

  20. ¿Qué es la Agenda Azul de las Mujeres? 1.

    Hilda

    19 Nov 2008 ... otras actividades productivas. Participación, gestión y conflictos. Tradicional oral, cultura y agua ... ambientales está subvalorado, incluyendo el tema de cambio climático. ... con enfoque de género. 1. 2. 3. Propuestas.

  1. Películas fluorescentes azules basadas en derivados de poli-2,7-fluorenofenilideno

    Mallavia, R.

    2004-04-01

    Full Text Available Quaternization of poly-(9,9-bis(6’-bromohexylfluorenephenylene by treatment with trimethylamine gas was used to obtain a water soluble ammonium salt copolymer. The neutral copolymer containing fluorene/phenylene alternating repeating units was obtained by a palladiumcatalyzed Suzuki coupling reaction. This strategy could be applied to prepare water soluble conjugated polymers with the ability to change the charge functionality. The polymers were characterized by gel permeation chromatography (GPC, 1H and 13C NMR spectroscopy, FT-IR spectroscopy, and thermogravimetric analysis (TGA. The neutral polymer was stable to over 300ºC, while the cationic polymer begins to degrade at 120ºC with a progressive loss of mass at 290ºC. The optical properties of the polymers were investigated in solution and solid phases by UV/VIS and fluorescent spectroscopy. Mesoporous silica thin films were prepared as a host matrix for the fluorescent copolymers.

    La cuaternización del poli-(9,9-bis(6’-bromohexilofluorenofenileno por tratamiento de trimetilamina gaseosa se emplea para obtener una sal de amonio del copolímero precursor soluble en agua. El copolímero neutro contiene unidades alternantes repetitivas de fluoreno/ fenilideno obtenidas mediante una acoplamiento de Suzuki con Pd (II. Los polímeros se caracterizaron por cromatografía de permeación (GPC, espectroscopia RMN de 1H y 13C , espectroscopia IR transformada de Fourier y análisis termogravimétrico (ATG. El polímero neutro mantiene la estabilidad hasta los 300ºC, mientras el derivado catiónico comienza a descomponer a 120ºC, con una progresiva perdida de masa hasta los 290ºC. Las propiedades ópticas de los polímeros se estudiaron en disolución y en películas mediante espectroscopias UV/VIS y de fluorescencia. Las películas delgadas de sílice mesoporosa se prepararon como materiales receptores de los copolímeros fluorescentes.

  2. Tela global e oceano azul: cinema 3D, o caso Brasil

    Andre Gatti

    2012-12-01

    Full Text Available A exibição de filmes de longa-metragem em 3D é a nova onda da indústria cinematográfica global. O que está acontecendo no Brasil? Quais problemas da implantação do 3D no país? Tudo ainda é muito recente, mas os resultados desta onda já podem ser percebidos.

  3. Synchrotron and Simulations Techniques Applied to Problems in Materials Science: Catalysts and Azul Maya Pigments

    Chianelli, R.

    2005-01-01

    Development of synchrotron techniques for the determination of the structure of disordered, amorphous and surface materials has exploded over the past twenty years due to the increasing availability of high flux synchrotron radiation and the continuing development of increasingly powerful synchrotron techniques. These techniques are available to materials scientists who are not necessarily synchrotron scientists through interaction with effective user communities that exist at synchrotrons such as the Stanford Synchrotron Radiation Laboratory (SSRL). In this article we review the application of multiple synchrotron characterization techniques to two classes of materials defined as ''surface compounds.'' One class of surface compounds are materials like MoS 2-x C x that are widely used petroleum catalysts used to improve the environmental properties of transportation fuels. These compounds may be viewed as ''sulfide supported carbides'' in their catalytically active states. The second class of ''surface compounds'' is the ''Maya Blue'' pigments that are based on technology created by the ancient Maya. These compounds are organic/inorganic ''surface complexes'' consisting of the dye indigo and palygorskite, a common clay. The identification of both surface compounds relies on the application of synchrotron techniques as described in this report

  4. Del príncipe azul al exitoso millonario: Cincuenta sombras de Grey

    Delia Montero Fernández

    2016-05-01

    obra; y, a su vez, contrastar si existe una correlación entre este éxito y una tendencia de fantasías sexuales sadomasoquistas que se hayan podido despertar a través de dicha novela. Con una muestra de 102 sujetos, los resultados desvelaron que estos mitos y micromachismos existentes en la sociedad son identificados en la teoría, pero aceptados en la práctica cotidiana; y que el sadomasoquismo no supuso un ingrediente de éxito para la repercusión de Cincuenta sombras de Grey

  5. Del rojo al azul : las pantallas de las dos Españas

    Josefina Martínez

    2009-01-01

    Full Text Available Durante la guerra civil española (1936- 1939 el cine se convirtió en una de las armas principales de la retaguardia. En la zona republicana se optó por la colectivización o la incautación de las salas de exhibición y de las empresas cinematográficas para convertirlas en el elemento clave de la propaganda plural del gobierno, partidos y sindicatos, así como en una fuente de ingresos. Las más de 400 obras producidas pretendían educar y elevar la moral de los españoles a la vez que solicitar al resto del mundo una ayuda que nunca llegó. Entre tanto, en la zona rebelde, con poco más de la cuarta parte de la producción, se creaba un aparato cinematográfico único, bajo las claras consignas censoras de la Falange que, tras el triunfo franquista, dirigirá las líneas de la producción cinematográfica nacional.Along the Spanish civil war (1936-1939 the cinema became one of the main weapons in the rear. The republican area the theatres and the cinema companies were either collectivized or withheld to turn them into a key element in the government propaganda, political parties and syndicates, as well as an incoming font. The more-than four hundred of titles produced tried to educate and raise the moral of the Spanish while using the films to pledge for the never coming external help. Meanwhile in the rebel area was produced only a quarter of the pieces, but there was created an unique cinematographic machine highly controlled and censored by the Spanish Falangist party which, after the triumph of Franco, would mark the lines of the national cinematographic production.

  6. Carcinoma superficial multifocal do pênis: ênfase ao teste do azul de toluidina

    Hélio Begliomini

    Full Text Available The author reports a case of penile multifocal superficial carcinoma in a white 66 years old male. The lesions on glans penis and prepuce were asymptomatic. Their appearence were plain reddish ulceration, irregular margins which became evident after circumcision. There was no palpable groin lymph node. The toluidine blue test was useful for guiding biopsies. A partial penectomy was undertaken with free surgical margins of tumor. In a follow-up of two years, penil erectile function is preserve with no tumor recurrence.

  7. XML-based DICOM data format.

    Yu, Cong; Yao, Zhihong

    2010-04-01

    To enhance the readability, improve the structure, and facilitate the sharing of digital imaging and communications in medicine (DICOM) files, this research proposed one kind of XML-based DICOM data format. Because XML Schema offers great flexibility for expressing constraints on the content model of elements, we used it to describe the new format, thus making it consistent with the one originally defined by DICOM. Meanwhile, such schemas can be used in the creation and validation of the XML-encoded DICOM files, acting as a standard for data transmission and sharing on the Web. Upon defining the new data format, we started with representing a single data element and further improved the whole data structure with the method of modularization. In contrast to the original format, the new one possesses better structure without loss of related information. In addition, we demonstrated the application of XSLT and XQuery. All of the advantages mentioned above resulted from this new data format.

  8. Exploring the value of usability feedback formats

    Nørgaard, Mie; Hornbæk, Kasper Anders Søren

    2009-01-01

    The format used to present feedback from usability evaluations to developers affects whether problems are understood, accepted, and fixed. Yet, little research has investigated which formats are the most effective. We describe an explorative study where three developers assess 40 usability findings...... presented using five feedback formats. Our usability findings comprise 35 problems and 5 positive comments. Data suggest that feedback serves multiple purposes. Initially, feedback must convince developers about the relevance of a problem and convey an understanding of this. Feedback must next be easy...... working with the feedback to address the usability problems, there were no significant differences among the developers' ratings of the value of the different formats. This suggests that all of the formats may serve equally well as reminders in later stages of working with usability problems...

  9. Teacher perspectives about using formative assessment

    Evans, Robert Harry; Clesham, Rose; Dolin, Jens

    2018-01-01

    This chapter examines three different classroom teacher perspectives when using ASSIST-ME project formative assessment methods as described in the introductory chapter. The first ‘teacher perspective’ is about changes in teacher self-efficacies while using formative assessment methods as monitored...... by a pre- and post-teacher questionnaire. Teachers who tried the unfamiliar formative methods of assessment (see introductory book chapter for these methods) as well as their colleagues who did not were surveyed. The second ‘teacher perspective’ examines changes in teachers’ subjective theories while...... trying project-specific formative assessment methods in Czech Republic. Analyses are done through case studies and interviews. The final part of the chapter looks at teacher perspectives while using an Internet-based application to facilitate formative assessment. The teacher use of the application...

  10. Analysis of constituents of earth formations

    Hertzog, R.C.; Grau, J.A.

    1981-01-01

    The composition of an earth formation is investigated by repetitively irradiating the formation with bursts of neutrons from a source and measuring an energy spectrum of the scattering gamma rays resulting from such irradiation e.g. by photomultiplier or solid state detector. The measured spectrum is thereafter analyzed by comparing it with a composite spectrum, made up of standard spectra, measured in a controlled environment, of constituents postulated to comprise the formation. As a result of such analysis, the proportions of the postulated constituents in the formation are determined. Since the measured spectrum is subject to degradation due to changes in the resolution of the detector, a filtering arrangement effects modification of the standard spectra in a manner which compensates for the changes in the detector and thereby provides for a more accurate determination of the constituents of the formation. Temperature is measured by sensor to compensate for temperature dependence of detector resolution. (author)

  11. Network Configuration Analysis for Formation Flying Satellites

    Knoblock, Eric J.; Wallett, Thomas M.; Konangi, Vijay K.; Bhasin, Kul B.

    2001-01-01

    The performance of two networks to support autonomous multi-spacecraft formation flying systems is presented. Both systems are comprised of a ten-satellite formation, with one of the satellites designated as the central or 'mother ship.' All data is routed through the mother ship to the terrestrial network. The first system uses a TCP/EP over ATM protocol architecture within the formation, and the second system uses the IEEE 802.11 protocol architecture within the formation. The simulations consist of file transfers using either the File Transfer Protocol (FTP) or the Simple Automatic File Exchange (SAFE) Protocol. The results compare the IP queuing delay, IP queue size and IP processing delay at the mother ship as well as end-to-end delay for both systems. In all cases, using IEEE 802.11 within the formation yields less delay. Also, the throughput exhibited by SAFE is better than FTP.

  12. FORMATIVE ASSESSMENT IN EFL CLASSROOM PRACTICES

    Ida Ayu Made Sri Widiastuti

    2017-03-01

    Full Text Available This study investigated the challenges and opportunities of formative assessment in EFL classes. It made use of qualitative research design by using indepth interviews to collect the required data. Three teachers and three students were involved as research participants in this study and they were intensively interviewed to get valid and reliable data regarding their understanding of formative assessment and the follow up actions they took after implementing formative assessment. The results of this study showed that the English teachers were found not to take appropriate follow up actions due to their low understanding of formative assessment. The teachers’ understanding could influence their ability in deciding the actions. This study indicates that EFL teachers need urgent further intensive training on the appropriate implementation of formative assessment and how follow up actions should be integrated into classroom practices

  13. THE SPECIAL STATUS OF EXOGENOUS WORD-FORMATION WITHIN THE GERMAN WORD-FORMATION SYSTEM

    Zhilyuk Sergey Aleksandrovich

    2014-01-01

    The article presents the properties of exogenous word-formation system taking into account the existence of two word-formation systems in modern German. On the basis of foreign research which reveal modern trends in German word-formation connected with the internationalization and the development of new European Latin language. The author defines key features of exogenous word-formation, i.e. foreign origin of wordformation units, unmotivated units, unmotivated interchange in base and affixes...

  14. Maggot excretions inhibit biofilm formation on biomaterials.

    Cazander, Gwendolyn; van de Veerdonk, Mariëlle C; Vandenbroucke-Grauls, Christina M J E; Schreurs, Marco W J; Jukema, Gerrolt N

    2010-10-01

    Biofilm-associated infections in trauma surgery are difficult to treat with conventional therapies. Therefore, it is important to develop new treatment modalities. Maggots in captured bags, which are permeable for larval excretions/secretions, aid in healing severe, infected wounds, suspect for biofilm formation. Therefore we presumed maggot excretions/secretions would reduce biofilm formation. We studied biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella oxytoca, Enterococcus faecalis, and Enterobacter cloacae on polyethylene, titanium, and stainless steel. We compared the quantities of biofilm formation between the bacterial species on the various biomaterials and the quantity of biofilm formation after various incubation times. Maggot excretions/secretions were added to existing biofilms to examine their effect. Comb-like models of the biomaterials, made to fit in a 96-well microtiter plate, were incubated with bacterial suspension. The formed biofilms were stained in crystal violet, which was eluted in ethanol. The optical density (at 595 nm) of the eluate was determined to quantify biofilm formation. Maggot excretions/secretions were pipetted in different concentrations to (nonstained) 7-day-old biofilms, incubated 24 hours, and finally measured. The strongest biofilms were formed by S. aureus and S. epidermidis on polyethylene and the weakest on titanium. The highest quantity of biofilm formation was reached within 7 days for both bacteria. The presence of excretions/secretions reduced biofilm formation on all biomaterials. A maximum of 92% of biofilm reduction was measured. Our observations suggest maggot excretions/secretions decrease biofilm formation and could provide a new treatment for biofilm formation on infected biomaterials.

  15. Formation Control for the MAXIM Mission

    Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

    2004-01-01

    Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

  16. Influence of fluorosurfactants on hydrate formation rates

    Kim, C.U.; Jeong, K.E.; Chae, H.J.; Jeong, S.Y. [Korea Reasearch Inst. of Chemical Technology, Alternative Chemicals/Fuel Research Center, Yuseong-Gu, Daejon (Korea, Republic of)

    2008-07-01

    Gas hydrates, or clathrates, are ice-like solids that forms when natural gas is in contact with liquid water or ice under high pressure and low temperature. There is significant interest in studying the storage and transportation of gas in the form of hydrates. However, a critical problem impacting the industrial application of gas hydrates for storage and transportation of natural gas is the slow formation rate of natural gas hydrate. Researchers have previously reported on the promotion effect of some additives on gas hydrate formation and hydrate gas content. Fluorosurfactants are significantly superior to nonfluorinated surfactants in wetting action, as well as stability in harsh environments, both thermal and chemical. This paper discussed an experimental investigation into the effects of fluorosurfactants with different ionic types on the formation of methane hydrate. The surfactants used were FSN-100 of DuPont Zonyl as non-ionic surfactant and FC-143 of DuPont as anionic surfactant. The paper discussed the experimental apparatus for methane hydrate formation. It also discussed hydrate formation kinetics and the series of hydrate formation experiments that were conducted in the presence of fluorosurfactants. Last, the paper explored the results of the study. It was concluded that anionic fluorosurfactant of FC-143 had a better promoting effect on methane hydrate formation compared with nonionic surfactant of FSN-100. 8 refs., 2 tabs., 2 figs.

  17. Planetesimal formation starts at the snow line

    Drążkowska, J.; Alibert, Y.

    2017-12-01

    Context. The formation stage of planetesimals represents a major gap in our understanding of the planet formation process. Late-stage planet accretion models typically make arbitrary assumptions about planetesimal and pebble distribution, while dust evolution models predict that planetesimal formation is only possible at some orbital distances. Aims: We wish to test the importance of the water snow line in triggering the formation of the first planetesimals during the gas-rich phase of a protoplanetary disk, when cores of giant planets have to form. Methods: We connected prescriptions for gas disk evolution, dust growth and fragmentation, water ice evaporation and recondensation, the transport of both solids and water vapor, and planetesimal formation via streaming instability into a single one-dimensional model for protoplanetary disk evolution. Results: We find that processes taking place around the snow line facilitate planetesimal formation in two ways. First, because the sticking properties between wet and dry aggregates change, a "traffic jam" inside of the snow line slows the fall of solids onto the star. Second, ice evaporation and outward diffusion of water followed by its recondensation increases the abundance of icy pebbles that trigger planetesimal formation via streaming instability just outside of the snow line. Conclusions: Planetesimal formation is hindered by growth barriers and radial drift and thus requires particular conditions to take place. The snow line is a favorable location where planetesimal formation is possible for a wide range of conditions, but not in every protoplanetary disk model, however. This process is particularly promoted in large cool disks with low intrinsic turbulence and an increased initial dust-to-gas ratio. The movie attached to Fig. 3 is only available at http://www.aanda.org

  18. Biofilm formation in a hot water system

    Bagh, L.K.; Albrechtsen, Hans-Jørgen; Arvin, Erik

    2002-01-01

    The biofilm formation rate was measured in situ in a hot water system in an apartment building by specially designed sampling equipment, and the net growth of the suspended bacteria was measured by incubation of water samples with the indigeneous bacteria. The biofilm formation rate reached......, in the sludge, or in the water from the distribution system was negligible. This indicated that bacterial growth took place on the inner surfaces in the hot water system and biofilm formation and detachment of bacteria could account for most of the suspended bacteria actually measured in hot water. Therefore...

  19. Formation of nuclear security culture in Ukraine

    V. I. Gavryliuk

    2014-06-01

    Full Text Available Issues of nuclear security culture formation are considered in the article. Information on establishing and ac-tivity of Working Group for formation and development of nuclear security culture being held during 2010 – 2013 is given. An issue of regulation of activity on formation and development of nuclear security culture is il-lustrated. Analysis of the survey results regarding efficiency assessment of the work aimed to form and develop of nuclear security culture of nuclear facilities is carried out. The results show that the nuclear security culture of the most of nuclear facilities in Ukraine has been formed and is at the stage of development.

  20. Formation of nuclear security culture in Ukraine

    Gavrilyuk, V.Yi.; Gavrilyuk-Burakova, A.V.; Drapej, S.S.; Parkhomenko, V.V.; Proskuryin, D.V.; Romanova, O.P.

    2014-01-01

    Issues of nuclear security culture formation are considered in the article. Information on establishing and activity of Working Group for formation and development of nuclear security culture being held during 2010 - 2013 is given. An issue of regulation of activity on formation and development of nuclear security culture is illustrated. Analysis of the survey results regarding efficiency assessment of the work aimed to form and develop of nuclear security culture of nuclear facilities is carried out. The results show that the nuclear security culture of the most of nuclear facilities in Ukraine has been formed and is at the stage of development

  1. Time-Dependent Dust Formation in Novae

    Kyung-Won Suh

    1991-06-01

    Full Text Available The dust formation processes in novae are investigated with close attention to recent infrared observations. Using mainly the classical nucleation theory, we have calculated the time scales of dust formation and growth in the environments of novae. Those time scales roughly resemble the typical observations. We have classified the dust-forming novae into three classes according to their explosion properties and the thermodynamic properties of dust grains. Oxygen grains from much later than carbon grains because of their thermodynamic properties. The effect of grain formation to the efficiency of stellar winds to drive the material outward is tested with newly obtained Planck mean values of dust grains.

  2. Formation of adduct of cerium (4) thenoyltrifluoroacetonate

    Anyfrieva, S.I.; Polyakova, G.V.; Snezhko, N.I.; Pechurova, N.I.; Martynenko, L.I.; Spitsyn, V.I.

    1981-01-01

    Adduct formation of thenoyltrifluoroacetonate of Ce(4) [Ce(TTFA) 4 ] with seven nitrogen- and oxygen-containing donor additional ligands is studied using the methods of IR-spectroscopy, derivatography, X-ray phase analysis. The presence of formation of Ce(TTFA) 4 adducts with phosphorus-containing additional ligands tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), triphenylphosphine oxide (TPPO); α, α'-dipyridyl (Dipy) and o-phenanthroline (Phen) is established. The adduct Ce(TTFA) 4 stable to reduction is formed with Dipy, and in the case of Phen, TBP, TOPO, TPPO in the process of adduct formation the reduction of Ce(4) to Ce(3) takes place [ru

  3. Carbon nanotube formation by laser direct writing

    Wu, Y.-T.; Su, H.-C.; Tsai, C.-M.; Liu, K.-L.; Chen, G.-D.; Huang, R.-H.; Yew, T.-R.

    2008-01-01

    This letter presents carbon nanotube (CNT) formation by laser direct writing using 248 nm KrF excimer pulsed laser in air at room temperature, which was applied to irradiate amorphous carbon (a-C) assisted by Ni catalysts underneath for the transformation of carbon species into CNTs. The CNTs were synthesized under appropriate combination of laser energy density and a-C thickness. The growth mechanism and key parameters to determine the success of CNT formation were also discussed. The demonstration of the CNT growth by laser direct writing in air at room temperature opens an opportunity of in-position CNT formation at low temperatures

  4. Distributed formation tracking using local coordinate systems

    Yang, Qingkai; Cao, Ming; Garcia de Marina, Hector

    2018-01-01

    This paper studies the formation tracking problem for multi-agent systems, for which a distributed estimator–controller scheme is designed relying only on the agents’ local coordinate systems such that the centroid of the controlled formation tracks a given trajectory. By introducing a gradient...... descent term into the estimator, the explicit knowledge of the bound of the agents’ speed is not necessary in contrast to existing works, and each agent is able to compute the centroid of the whole formation in finite time. Then, based on the centroid estimation, a distributed control algorithm...

  5. Extrasolar planets formation, detection and dynamics

    Dvorak, Rudolf

    2008-01-01

    This latest, up-to-date resource for research on extrasolar planets covers formation, dynamics, atmospheres and detection. After a look at the formation of giant planets, the book goes on to discuss the formation and dynamics of planets in resonances, planets in double stars, atmospheres and habitable zones, detection via spectra and transits, and the history and prospects of ESPs as well as satellite projects.Edited by a renowned expert in solar system dynamics with chapters written by the leading experts in the method described -- from the US and Europe -- this is an ideal textbook for g

  6. Emissions and dioxins formation from waste incinerators

    Carbone, A.I.; Zagaroli, M.

    1989-01-01

    This paper describes current knowledge on dioxins formation and emission from waste incinerators. The pertinent Italian law and effects on man health are dealt with, too. The picture of existing municipal incinerators is presented concerning both the actual emission levels and the monitored levels in the environment. Sampling and analysis systems of these organic chlorinated micro-pollutants and current theories on precursors, formation mechanisms, and influence of different parameters are also described. The last section deals with some of the techniques that can be used to reduce dioxins formation and emission from municipal incinerators. (author)

  7. Promoting proximal formative assessment with relational discourse

    Scherr, Rachel E.; Close, Hunter G.; McKagan, Sarah B.

    2012-02-01

    The practice of proximal formative assessment - the continual, responsive attention to students' developing understanding as it is expressed in real time - depends on students' sharing their ideas with instructors and on teachers' attending to them. Rogerian psychology presents an account of the conditions under which proximal formative assessment may be promoted or inhibited: (1) Normal classroom conditions, characterized by evaluation and attention to learning targets, may present threats to students' sense of their own competence and value, causing them to conceal their ideas and reducing the potential for proximal formative assessment. (2) In contrast, discourse patterns characterized by positive anticipation and attention to learner ideas increase the potential for proximal formative assessment and promote self-directed learning. We present an analysis methodology based on these principles and demonstrate its utility for understanding episodes of university physics instruction.

  8. Right timing in formative program evaluation.

    Hall, Jori; Freeman, Melissa; Roulston, Kathy

    2014-08-01

    Since many educational researchers and program developers have limited knowledge of formative evaluation, formative data may be underutilized during the development and implementation of an educational program. The purpose of this article is to explain how participatory, responsive, educative, and qualitative approaches to formative evaluation can facilitate a partnership between evaluators and educational researchers and program managers to generate data useful to inform program implementation and improvement. This partnership is critical, we argue, because it enables an awareness of when to take appropriate action to ensure successful educational programs or "kairos". To illustrate, we use examples from our own evaluation work to highlight how formative evaluation may facilitate opportune moments to (1) define the substance and purpose of a program, (2) develop understanding and awareness of the cultural interpretations of program participants, and (3) show the relevance of stakeholder experiences to program goals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Septum formation of the lateral ventricles

    Celik, Hakan H.; Aldur, Mustafa M.; Tatar, I.; Tascioglu, A.B.

    2005-01-01

    In an MRI study examining anomalies of the septum pellucidum in 505 cases, we detected bilateral septum formation of the lateral ventricles in a 17-months-old-baby. In this study, we evaluate 505 (242 males and 263 females) patients referred to the Emaray Imaging Center, Ankara, Turkey with various prediagnoses. We specially selected all the cases from a non-psychotic population. We obtained MRI scans on a 1-Tesla imager (Picker International, Highland Heights, Ohio, USA), with slices of 5 and 6 mm thickness. In the axial and coronal sections, we observed septum formation laterally between the anterior horn and the ventricular body of the lateral ventricles. Radio opaque septum formations started from the caudate nucleus and stretched to the genu of the corpus callosum. There was a second septum formation between the posterior horn and the ventricular body of the right lateral ventricle. It started from the caudate nucleus and stretched to the cavum vergae. (author)

  10. Physics of star formation in galaxies

    Palla, F

    2002-01-01

    Begining with a historical introduction, ""Star Formation: The Early History"", this text then presents two long articles on ""Pre-Main-Sequence Evolution of Stars and Young Clusters"" and ""Observations of Young Stellar Objects"".

  11. Levels of Elitological Formation of Personality

    N B Karabushchenko

    2011-12-01

    Full Text Available The article describes the main stages of the elitological formation of a personality: the basic level of elitological knowledge, elitological literacy, elitological competence, elitological culture, elite-oriented outlook.

  12. Microbial processes in banded iron formation deposition

    Posth, Nicole; Konhauser, Kurt; Kappler, Andreas

    2013-01-01

    , remains unresolved. Evidence of an anoxic Earth with only localized oxic areas until the Great Oxidation Event ca 2·45 to 2·32 Ga makes the investigation of O2-independent mechanisms for banded iron formation deposition relevant. Recent studies have explored the long-standing proposition that Archean......Banded iron formations have been studied for decades, particularly regarding their potential as archives of the Precambrian environment. In spite of this effort, the mechanism of their deposition and, specifically, the role that microbes played in the precipitation of banded iron formation minerals...... banded iron formations may have been formed, and diagenetically modified, by anaerobic microbial metabolisms. These efforts encompass a wide array of approaches including isotope, ecophysiological and phylogeny studies, molecular and mineral marker analysis, and sedimentological reconstructions. Herein...

  13. Formation of soap bubbles by gas jet

    Zhou, Maolei; Li, Min; Chen, Zhiyuan; Han, Jifeng; Liu, Dong

    2017-12-01

    Soap bubbles can be easily generated by various methods, while their formation process is complicated and still worth studying. A model about the bubble formation process was proposed in the study by Salkin et al. [Phys. Rev. Lett. 116, 077801 (2016)] recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after a detailed study of these experiments, we found that the bubbles could be generated in two velocity ranges which corresponded to the laminar and turbulent gas jet, respectively, and the predicted threshold was only effective for turbulent gas flow. The study revealed that the bubble formation was greatly influenced by the aerodynamics of the gas jet blowing to the film, and these results will help to further understand the formation mechanism of the soap bubble as well as the interaction between the gas jet and the thin liquid film.

  14. The Role of Emotions in Delusion Formation

    Smurzyńska Adrianna

    2016-12-01

    Full Text Available The text concerns the role of emotions in delusion formation. Provided are definitions from DSM-V and DSM-IV-R and the problems found in those definitions. One of them, the problem of delusion formation, is described when providing cognitive theories of delusions. The core of the paper is a presentation of the emotional and affective disorders in delusions, especially Capgras delusion and Cotard delusion. The author provides a comparison of the kinds of delusions and the conclusions taken from neuroimaging studies. As a result of the fact that an explanation of delusion formation focusing on emotional problems turns out to be insufficient, the author provides examples of the reasoning impairments which coexist with them. At the end of the article, some hypotheses are proposed concerning the role of emotions and reasoning in delusion formation and the relation between belief disorders and emotional disorders.

  15. Optimized Lift for Autonomous Formation Flight

    National Aeronautics and Space Administration — Experimental in-flight evaluations have demonstrated that the concept of formation flight can reduce fuel consumption of trailing aircraft by 10 percent. Armstrong...

  16. MP3 the meaning of a format

    Sterne, Jonathan

    2012-01-01

    Jonathan Sterne shows that understanding the historical meaning of the MP3, the world's most common format for recorded audio, involves rethinking the place of digital technologies in the broader universe of twentieth-century communication history.

  17. Simulating Precambrian banded iron formation diagenesis

    Posth, Nicole R.; K??hler, Inga; D. Swanner, Elizabeth

    2013-01-01

    Post-depositional diagenetic alteration makes the accurate interpretation of key precipitation processes in ancient sediments, such as Precambrian banded iron formations (BIFs), difficult. While microorganisms are proposed as key contributors to BIF deposition, the diagenetic transformation...

  18. The NeXus data format.

    Könnecke, Mark; Akeroyd, Frederick A; Bernstein, Herbert J; Brewster, Aaron S; Campbell, Stuart I; Clausen, Björn; Cottrell, Stephen; Hoffmann, Jens Uwe; Jemian, Pete R; Männicke, David; Osborn, Raymond; Peterson, Peter F; Richter, Tobias; Suzuki, Jiro; Watts, Benjamin; Wintersberger, Eugen; Wuttke, Joachim

    2015-02-01

    NeXus is an effort by an international group of scientists to define a common data exchange and archival format for neutron, X-ray and muon experiments. NeXus is built on top of the scientific data format HDF5 and adds domain-specific rules for organizing data within HDF5 files, in addition to a dictionary of well defined domain-specific field names. The NeXus data format has two purposes. First, it defines a format that can serve as a container for all relevant data associated with a beamline. This is a very important use case. Second, it defines standards in the form of application definitions for the exchange of data between applications. NeXus provides structures for raw experimental data as well as for processed data.

  19. Quilting after mastectomy significantly reduces seroma formation

    reduce or prevent seroma formation among mastectomy patients ... of this prospective study is to evaluate the effect of surgical quilting ... Seroma was more common in smokers (p=0.003) and was not decreased by the .... explain its aetiology.

  20. The formation of planets by disc fragmentation

    Stamatellos Dimitris

    2013-04-01

    Full Text Available I discuss the role that disc fragmentation plays in the formation of gas giant and terrestrial planets, and how this relates to the formation of brown dwarfs and low-mass stars, and ultimately to the process of star formation. Protostellar discs may fragment, if they are massive enough and can cool fast enough, but most of the objects that form by fragmentation are brown dwarfs. It may be possible that planets also form, if the mass growth of a proto-fragment is stopped (e.g. if this fragment is ejected from the disc, or suppressed and even reversed (e.g by tidal stripping. I will discuss if it is possible to distinguish whether a planet has formed by disc fragmentation or core accretion, and mention of a few examples of observed exoplanets that are suggestive of formation by disc fragmentation.

  1. Stochastic Models of Molecule Formation on Dust

    Charnley, Steven; Wirstroem, Eva

    2011-01-01

    We will present new theoretical models for the formation of molecules on dust. The growth of ice mantles and their layered structure is accounted for and compared directly to observations through simulation of the expected ice absorption spectra

  2. Continuum Modeling of Biological Network Formation

    Albi, Giacomo; Burger, Martin; Haskovec, Jan; Markowich, Peter A.; Schlottbom, Matthias

    2017-01-01

    We present an overview of recent analytical and numerical results for the elliptic–parabolic system of partial differential equations proposed by Hu and Cai, which models the formation of biological transportation networks. The model describes

  3. Star formation: Sibling rivalry begins at birth

    Kratter, Kaitlin M.

    2015-02-01

    High-resolution astronomical observations of a nearby molecular gas cloud have revealed a quadruplet of stars in the act of formation. The system is arguably the youngest multiple star system detected so far. See Letter p.213

  4. KINETICS AND MECHANISM OF PRUSSIAN BLUE FORMATION ...

    Preferred Customer

    the 137Cs from radioactive waste solutions [7] and from humans and animals exposed to nuclear accidents [8]. PB and ... ferrocyanide ion resulting in formation of PB is used as a qualitative test for ferric ion. Although. Prussian ..... zeolites [21].

  5. 4 dnja v drugom formate / Dmitri Babitshenko

    Babitshenko, Dmitri

    2007-01-01

    25.-28. okt. Teises Teatris toimuvast festivalist "Teine formaat 2. Sügishooaeg" (Drugoi format 2), mille programmis on muusikat, teatrietendusi, luulet, tantsulavastusi ja filme. Festivali organiseerija on Teise Teatri administraator Anastassia Kulkova

  6. Transient Exciplex Formation Electron Transfer Mechanism

    Michael G. Kuzmin

    2011-01-01

    Full Text Available Transient exciplex formation mechanism of excited-state electron transfer reactions is analyzed in terms of experimental data on thermodynamics and kinetics of exciplex formation and decay. Experimental profiles of free energy, enthalpy, and entropy for transient exciplex formation and decay are considered for several electron transfer reactions in various solvents. Strong electronic coupling in contact pairs of reactants causes substantial decrease of activation energy relative to that for conventional long-range ET mechanism, especially for endergonic reactions, and provides the possibility for medium reorganization concatenated to gradual charge shift in contrast to conventional preliminary medium and reactants reorganization. Experimental criteria for transient exciplex formation (concatenated mechanism of excited-state electron transfer are considered. Available experimental data show that this mechanism dominates for endergonic ET reactions and provides a natural explanation for a lot of known paradoxes of ET reactions.

  7. Bonded exciplex formation: electronic and stereoelectronic effects.

    Wang, Yingsheng; Haze, Olesya; Dinnocenzo, Joseph P; Farid, Samir; Farid, Ramy S; Gould, Ian R

    2008-12-18

    As recently proposed, the singlet-excited states of several cyanoaromatics react with pyridine via bonded-exciplex formation, a novel concept in photochemical charge transfer reactions. Presented here are electronic and steric effects on the quenching rate constants, which provide valuable support for the model. Additionally, excited-state quenching in poly(vinylpyridine) is strongly inhibited both relative to that in neat pyridine and also to conventional exciplex formation in polymers, consistent with a restrictive orientational requirement for the formation of bonded exciplexes. Examples of competing reactions to form both conventional and bonded exciplexes are presented, which illustrate the delicate balance between these two processes when their reaction energetics are similar. Experimental and computational evidence is provided for the formation of a bonded exciplex in the reaction of the singlet excited state of 2,6,9,10-tetracyanoanthracene (TCA) with an oxygen-substituted donor, dioxane, thus expanding the scope of bonded exciplexes.

  8. The formation of citizens: the pediatrician's role

    Dioclécio Campos Júnior

    2016-05-01

    Conclusion: In the light of the disclosed scientific evidence, the pediatrician emerges as the most differentiated professional to provide preventive and curative care indispensable to the skilled formation of a healthy citizen.

  9. Resonance formation in photon-photon collisions

    Gidal, G.

    1988-08-01

    Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the γγ* production of spin-one resonances. 37 refs., 17 figs., 5 tabs

  10. Inflow of atomic gas fuelling star formation

    Michałowski, M. J.; Gentile, G.; Hjorth, Jeppe

    2016-01-01

    Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation in these ga......Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation...... in these galaxies may be fuelled by recent inflow of metal-poor atomic gas. While this process is debated, it can happen in low-metallicity gas near the onset of star formation because gas cooling (necessary for star formation) is faster than the Hi-to-H2 conversion....

  11. Star Formation in low mass galaxies

    Mehta, Vihang

    2018-01-01

    Our current hierarchical view of the universe asserts that the large galaxies we see today grew via mergers of numerous smaller galaxies. As evidenced by recent literature, the collective impact of these low mass galaxies on the universe is more substantial than previously thought. Studying the growth and evolution of these low mass galaxies is critical to our understanding of the universe as a whole. Star formation is one of the most important ongoing processes in galaxies. Forming stars is fundamental to the growth of a galaxy. One of the main goals of my thesis is to analyze the star formation in these low mass galaxies at different redshifts.Using the Hubble UltraViolet Ultra Deep Field (UVUDF), I investigate the star formation in galaxies at the peak of the cosmic star formation history using the ultraviolet (UV) light as a star formation indicator. Particularly, I measure the UV luminosity function (LF) to probe the volume-averaged star formation properties of galaxies at these redshifts. The depth of the UVUDF is ideal for a direct measurement of the faint end slope of the UV LF. This redshift range also provides a unique opportunity to directly compare UV to the "gold standard" of star formation indicators, namely the Hα nebular emission line. A joint analysis of the UV and Hα LFs suggests that, on average, the star formation histories in low mass galaxies (~109 M⊙) are more bursty compared to their higher mass counterparts at these redshifts.Complementary to the analysis of the average star formation properties of the bulk galaxy population, I investigate the details of star formation in some very bursty galaxies at lower redshifts selected from Spitzer Large Area Survey with Hyper-Suprime Cam (SPLASH). Using a broadband color-excess selection technique, I identify a sample of low redshift galaxies with bright nebular emission lines in the Subaru-XMM Deep Field (SXDF) from the SPLASH-SXDF catalog. These galaxies are highly star forming and have

  12. Charmonium formation and suppression in nuclear matter

    Xu Jiajun; Wang Jia; Zhuang Chao; Zhuang Pengfei

    2005-01-01

    The coupling Schroedinger equations describing the evolution of cc-bar states in nuclear matter are analytically and systematically solved via perturbation method, and the correlation between charmonium formation and nuclear absorption is investigated. After calculating J/Ψ and Ψ' suppression in nucleon-nucleus collisions and comparing with experiment data, it is found that the formation time effect plays an important rule in charmonium suppression, especially in Ψ' suppression. (authors)

  13. THE STAGES OF ACCOUNTING POLICIES FORMATION

    Kafka, Sofiia

    2017-01-01

    In the article the research of the existing scientists’ approaches to the procedure of the company accounting policy formation have been done, their critical analysis has been made, the major groups of issues and problems raised in scientific works have been found out, and those ones, which require the further up-to- date refinement, have been identified: the formation of the stages in projecting of the accounting policy in accordance with requirements of legislation. For the purposes of stud...

  14. Formation of soap bubbles by gas jet

    Zhou, M. L.; Li, M.; Chen, Z. Y.; Han, J. F.; Liu, D.

    2017-01-01

    Soap bubbles can be easily generated by varies methods, while their formation process is complicated and still worth study. A model about the bubble formation process was proposed in Phys. Rev. Lett. 116, 077801 recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after repeating these experiments, we found the bubbles could be generated in two velocities ranges which corresponded to laminar and turbulent gas jet respective...

  15. Insights from simulations of star formation

    Larson, Richard B

    2007-01-01

    Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circumstellar discs often form from the gas being accreted by the forming stars, and accretion from these discs may be episodic, driven by gravitational instabilities or by protostellar interactions. Star-forming clouds typically develop filamentary structures, which may, along with the thermal physics, play an important role in the origin of stellar masses because of the sensitivity of filament fragmentation to temperature variations. Simulations of the formation of star clusters show that the most massive stars form by continuing accretion in the dense cluster cores, and this again is a runaway process that couples star formation and cluster formation. Star-forming clouds also tend to develop hierarchical structures, and smaller groups of forming objects tend to merge into progressively larger ones, a generic feature of self-gravitating systems that is common to star formation and galaxy formation. Because of the large range of scales and the complex dynamics involved, analytic models cannot adequately describe many aspects of star formation, and detailed numerical simulations are needed to advance our understanding of the subject. 'The purpose of computing is insight, not numbers.' Richard W Hamming, in Numerical Methods for Scientists and Engineers (1962) 'There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.' William Shakespeare, in Hamlet, Prince of Denmark (1604) (key issues review)

  16. Insights from simulations of star formation

    Larson, Richard B [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States)

    2007-03-15

    Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of nearly singular peaks in density, followed by the accretional growth of embryo stars that form at these density peaks. Circumstellar discs often form from the gas being accreted by the forming stars, and accretion from these discs may be episodic, driven by gravitational instabilities or by protostellar interactions. Star-forming clouds typically develop filamentary structures, which may, along with the thermal physics, play an important role in the origin of stellar masses because of the sensitivity of filament fragmentation to temperature variations. Simulations of the formation of star clusters show that the most massive stars form by continuing accretion in the dense cluster cores, and this again is a runaway process that couples star formation and cluster formation. Star-forming clouds also tend to develop hierarchical structures, and smaller groups of forming objects tend to merge into progressively larger ones, a generic feature of self-gravitating systems that is common to star formation and galaxy formation. Because of the large range of scales and the complex dynamics involved, analytic models cannot adequately describe many aspects of star formation, and detailed numerical simulations are needed to advance our understanding of the subject. 'The purpose of computing is insight, not numbers.' Richard W Hamming, in Numerical Methods for Scientists and Engineers (1962) 'There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.' William Shakespeare, in Hamlet, Prince of Denmark (1604) (key issues review)

  17. Search of massive star formation with COMICS

    Okamoto, Yoshiko K.

    2004-04-01

    Mid-infrared observations is useful for studies of massive star formation. Especially COMICS offers powerful tools: imaging survey of the circumstellar structures of forming massive stars such as massive disks and cavity structures, mass estimate from spectroscopy of fine structure lines, and high dispersion spectroscopy to census gas motion around formed stars. COMICS will open the next generation infrared studies of massive star formation.

  18. Star Formation Histories of Nearby Dwarf Galaxies

    Grebel, Eva K.

    2000-01-01

    Properties of nearby dwarf galaxies are briefly discussed. Dwarf galaxies vary widely in their star formation histories, the ages of their subpopulations, and in their enrichment history. Furthermore, many dwarf galaxies show evidence for spatial variations in their star formation history; often in the form of very extended old populations and radial gradients in age and metallicity. Determining factors in dwarf galaxy evolution appear to be both galaxy mass and environment. We may be observi...

  19. Radiation pressure in super star cluster formation

    Tsang, Benny T.-H.; Milosavljević, Miloš

    2018-05-01

    The physics of star formation at its extreme, in the nuclei of the densest and the most massive star clusters in the universe—potential massive black hole nurseries—has for decades eluded scrutiny. Spectroscopy of these systems has been scarce, whereas theoretical arguments suggest that radiation pressure on dust grains somehow inhibits star formation. Here, we harness an accelerated Monte Carlo radiation transport scheme to report a radiation hydrodynamical simulation of super star cluster formation in turbulent clouds. We find that radiation pressure reduces the global star formation efficiency by 30-35%, and the star formation rate by 15-50%, both relative to a radiation-free control run. Overall, radiation pressure does not terminate the gas supply for star formation and the final stellar mass of the most massive cluster is ˜1.3 × 106 M⊙. The limited impact as compared to in idealized theoretical models is attributed to a radiation-matter anti-correlation in the supersonically turbulent, gravitationally collapsing medium. In isolated regions outside massive clusters, where the gas distribution is less disturbed, radiation pressure is more effective in limiting star formation. The resulting stellar density at the cluster core is ≥108 M⊙ pc-3, with stellar velocity dispersion ≳ 70 km s-1. We conclude that the super star cluster nucleus is propitious to the formation of very massive stars via dynamical core collapse and stellar merging. We speculate that the very massive star may avoid the claimed catastrophic mass loss by continuing to accrete dense gas condensing from a gravitationally-confined ionized phase.

  20. The effect of anisotropy on galaxy formation

    Burkert, A.; Hensler, G.

    1987-01-01

    Two-dimensional calculations of galaxy formation are presented. Gas and stars are taken into account as two distinct components interacting by star formation and stellar mass loss. While the gas is described by means of the Eulerian equation, the authors allow for an anisotropic velocity distribution among the stars by applying the collisionless Boltzmann equation. In the first model, the authors succeed in developing totally different stellar populations forming a halo and a disc. (author)