12,489 research outputs found
Validation of RELAP5 model of experimental test rig simulating the natural convection in MTR research reactors
No full textIn an attempt to understand the buildup of natural circulation in MTR pool type upward flow research reactors after loss of power, an experimental test rig was built to simulate the loop of natural circulation in MTR reactors. In this test rig the reactor core is simulated by two electrically heated, rectangular parallel channels. The channel's coolant and surface temperature at different operating conditions were measured. The measurements and their interpretation were published by the first three authors.
In the present article the thermal hydraulic behavior of the test rig is complemented by theoretical analysis using RELAP5 system code. The analysis consisting of two parts; in the first part RELAP5 model is validated against the experimental measurements and in the second part the other non-measured hydraulic parameters are presented and analyzed.
In spite of the low pressure of the test rig, the results show that RELAP5 Mode 3.3 qualitatively predicts the thermal hydraulic behaviour and the accompanied phenomenon of flow inversion in such facilities. Quantitatively, there is a difference between the predicted and measured values especially the surface temperature of channel's wall. This difference may be return to the uncertainties in initial conditions of experimental runs, the position of the thermocouples which buried inside the heat structure, and the heat transfer package in RELAP5
Vasoactive intestinal peptide induces proliferation of human hepatocytes
No full textOBJECTIVES:Proliferation of hepatocytes in vitro can be stimulated by growth factors such as epidermal growth factor (EGF), but the role of vasoactive intestinal peptide (VIP) remains unclear. We have investigated the effect of VIP on maintenance and proliferation of human hepatocytes.MATERIALS AND METHODS:Human hepatocytes were isolated from liver specimens obtained from patients undergoing liver surgery. Treatment with VIP or EGF was started 24 h after plating and continued for 3 or 5 d. DNA replication was investigated by Bromodeoxyuridine (BrdU) incorporation and cell viability detected by MTT assay. Cell lysate was analysed by western blotting and RT-PCR. Urea and albumin secretion into the culture supernatants were measured.RESULTS:VIP increased DNA replication in hepatocytes in a dose-dependant manner, with a peak response at day 3 of treatment. VIP treatment was associated with an increase in mRNA expression of antigen identified by monoclonal antibody Ki-67 (MKI-67) and Histone Cluster 3 (H3) genes. Western blotting analysis showed that VIP can induce a PKA/B-Raf dependant phosphorylation of extracellular signal-regulated kinases (ERK). Although EGF can maintain hepatocyte functions up to day 5, no marked efffect was found with VIP.CONCLUSIONS:VIP induces proliferation of human hepatocytes with little or no effect on hepatocyte differentiation. Further investigation of the role of VIP is required to determine if it may ultimately support therapeutic approaches of liver disease
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
Geochemical variability among stratiform chromitites and ultramafic rocks from Western Makran, South Iran
No full textThe geochemical compositions of minerals from the Moho transition zone of ophiolites potentially can help to understand the magmatic evolution of the ophiolites, and subsequent mantle-melt interactions. The Jurassic-Late Cretaceous Makran ophiolite of south Iran comprises one of the most extensive tracts of oceanic crust which were scraped off and preserved in an accretionary complex. The Makran ophiolite records traces of MORB-OIB-type magmatism during the Jurassic, but mostly supra-subduction zone magmatic activity during the Late Cretaceous. Despite a few geochemical studies on the crustal rocks, the nature and geochemical signatures of the mantle rocks from this ophiolite remain controversial. The Sorkhband mantle-crust transition zone underlying crustal cumulates in the western Makran consists of stratiform chromitites, harzburgites, chromite-rich dunites and dunites, with crosscutting dikes of olivine websterite and olivine clinopyroxenite. Major- and trace-element compositions of clinopyroxene grains in olivine websterite and clinopyroxenite dikes indicate crystallization from melts similar to boninites and low-Ti fore-arc basalts. Spinel compositions in olivine websterite and clinopyroxenite dikes suggest crystal fractionation from boninitic or high- Mg# magmas have played a major role in the genesis these rocks. We propose a two-stage model for the formation of the Sorkhband dunites including (1) supra-subduction zone-related melt infiltrates through harzburgites in the mantle-crust transition zone to dissolve peridotite orthopyroxene and leave dunites with high forsterite-NiO olivines, and (2) boninitic melts accumulate and react with surrounding harzburgites to crystallize cumulate dunites with low-Mg# olivine and high-Ti spinels. We conclude that there have been temporal changes in the composition of mantle melts in the fore-arc mantle section of the Makran ophiolite during the initial subduction of the Neotethyan ocean beneath the Lut block during the Late Cretaceous
Distribution and habitat structure of Ocypode gaudichaudii H. Milne Edwards & Lucas, 1843, in sandy beaches of Northern Chile
No full textTen sandy beaches along the coast of northern Chile (20-23 degreesS) were studied in December 1998, to examine the distribution, abundance, and habitat characteristics of the crab Ocypode gaudichaudii. Beach width. slope, and intertidal fringes were identified, and Dean's parameter, describing beach morphodynamic status, was calculated. Crabs were collected and burrows and physical characteristics of the burrow zones analysed. The burrow zone extended primarily across the dry and retention zones. Physical properties across the burrow areas did not influence burrow characteristics. Significant differences in burrow density were detected both within and among the 10 sandy beaches. These differences were not related to morphodynamic beach types, but could be explained by related aspects, such as the height of the drift line, and the width and slope of dry and retention zones. We linked these results to behavioural and not just to physical causes.PT: J; CR: DUGAN JE, 1991, J EXP MAR BIOL ECOL, V150, P63 DUGAN JE, 1996, REV CHIL HIST NAT, V69, P579 EMERY KO, 1938, J SEDIMENT PETROL, V8, P105 EMERY KO, 1961, LIMNOL OCEANOGR, V6, P90 JAMES RJ, 1996, ESTUAR COAST SHELF S, V43, P81 JARAMILLO E, 1987, VIE MILLIEU, V37, P165 JARAMILLO E, 1993, ESTUAR COAST SHELF S, V37, P615 JARAMILLO E, 1993, MAR ECOL-PROG SER, V101, P105 JARAMILLO E, 1998, REV CHIL HIST NAT, V71, P459 KOEPCKE H, 1953, CONTRIBUCION CONOCIM, V13, P9 KOEPCKE HW, 1952, PUBLICACION MUSEO NA, V8, P1 KURIHARA Y, 1989, MAR BIOL, V101, P153 LUCAS, 1843, CRUSTACEANA, V71, P47 MCARDLE SB, 1992, J COASTAL RES, V8, P398 MCLACHLAN A, 1980, J ZOOL, V15, P57 MCLACHLAN A, 1993, J COASTAL RES, V15, P27 MCLACHLAN A, 1995, J EXP MAR BIOL ECOL, V187, P147 MCLACHLAN A, 1995, OCEANOGR MAR BIOL, V33, P305 SEWARDTHOMPSON B, 1973, SEDIMENTOLOGY, V11, P83 SHOBER UM, 1993, MAR BIOL, V116, P53 SHORT AD, 1983, SANDY BEACHES ECOSYS, P133 SHUCHMAN E, 1978, MAR BIOL, V49, P255 SOKAL RR, 1994, BIOMETRY, P1 TROTT TJ, 1988, CRUSTACEANA, V55, P217 WADA K, 1993, MAR BIOL, V115, P47 WARBURG MR, 1979, MAR BEHAV PHYSL, V6, P147 WOLCOTT TG, 1978, J EXP MAR BIOL ECOL, V31, P67; NR: 27; TC: 3; J9: CRUSTACEANA; PN: Part 1; PG: 13; GA: 420GTSource type: Electronic(1
Conservatismo en el simbolismo de Oaxaca: un breve informe.. Anales del Instituto Nacional de Antropología e Historia. Num. 49 Tomo I (1967-1968) Séptima Época (1967-1976)
No full textCaso, A. 1928 Las Estelas Zapotecas. Monografías del Museo Nacional de Arqueología, Historia y Etnografía. México.Caso, A. y Bernal, l. 1952 Urnas de Oaxaca. Memorias del Instituto Nacional de Antropología e Historia, II. México.Boos, Frank H. 1964 Las Urnas Zapotecas en el Museo Real de Ontario. Corpus Antiquitatum Americanensium, vol. l. Instituto Nacional de Antropología e Historia. México.Boos, Frank H. 1965 The Oaxacan Urn of the Zapotec God One Z and the Urn of his Feminine Companion. Wadsworth Athenaeum Bulletin. Sixth series, vol. 1. No. 2. Hartford, Connecticut.Boos, Frank H. 1966 The Ceramic Sculptures of Ancient Oaxaca. A. S. Barnes & Co., New York y Thomas Yoseloff Ltd., London.Leigh, H. 1958 An Identification of Zapotec Day Names. Boletín de Estudios Oaxaqueños, No. 6. Mexico City College, México.Paddock, J. 1966 Ancient Oaxaca. Stanford University Press
Neutrophilia, gelatinase release and microvascular leakage induced by human mast cell tryptase in a mouse model: lack of a role of protease activated receptor 2 (PAR2)
No full textBackground: tryptase, the most abundant protease of the human mast cell, has been implicated as a key mediator of allergic inflammation that acts through activation of PAR2.Objectives: to investigate the contribution of PAR2 in the pro-inflammatory actions mediated by tryptase in a mice model.Methods: we have injected recombinant human βII-tryptase into the peritoneum of PAR2-deficient and wild-type C57BL/6 mice. After 6, 12 and 24 hours mice were euthanized, peritoneal lavage performed and inflammatory changes investigated.Results: tryptase stimulated an increase in neutrophil numbers in the peritoneum, but responses did not differ between PAR2-deficient and wild-type mice. Heat-inactivation of tryptase or pre-incubation with a selective tryptase inhibitor reduced neutrophilia, but neutrophil accumulation was not elicited with a peptide agonist of PAR2 (SLIGRL-NH2 ). Zymography indicated that tryptase stimulated the release of matrix metalloproteinases (MMP) 2 and 9 in the peritoneum of both mouse strains. Studies involving immunomagnetic isolation of neutrophils suggested that neutrophils represent the major cellular source of tryptase-induced MMP2 and MMP9. At 24 h after tryptase injection there was increased microvascular leakage as indicated by high levels of albumin in peritoneal lavage fluid, and this appeared to be partially abolished by heat-inactivating tryptase or addition of a protease inhibitor. There was no corresponding increase in levels of histamine or total protein. The extent of tryptase-induced microvascular leakage or gelatinase release into the peritoneum did not differ between PAR2-deficient and wild-type mice.Conclusions: our findings indicate that tryptase is a potent stimulus for neutrophil accumulation, MMP release and microvascular leakage. Though these actions required an intact catalytic site, the primary mechanism of tryptase in vivo would appear to involve processes independent of PAR2. This article is protected by copyright. All rights reserved.</p
Geochemistry and tectonic significance of the Fannuj-Maskutan SSZ-type ophiolite (Inner Makran, SE Iran)
No full textThe nature and geodynamic setting of Inner Makran ophiolites (SE Iran) are controversial and are the focus of a growing debate. The Fannuj-Maskutan ophiolite complex (central Inner Makran) is made up of lherzolites, harzburgites, layered and isotropic gabbros and diabase dikes and basaltic lavas. Here we present new textural description, mineral and whole-rock chemistry of peridotites together with bulk geochemistry of magmatic mafic rocks and U-Pb geochronology and Lu-Hf isotopes of inherited zircons in gabbros, with the aim to reconstruct the petrogenesis of the Fannuj-Maskutan ophiolite. The results indicate to a subduction-metasomatized depleted mantle source experienced 10–20% of partial melting. A transition from IAT-gabbros to E-MORB-basalts is also outlined. We interpret the obtained results as evidence for the Fannuj-Maskutan genesis in a supra-subduction zone (SSZ) basin developed in the Iranian cadomian crust as indicated by the presence of inherited Cadomian zircons (ca. 515 Ma, εHf(t): −13.6–+11.2). Comparing the Fannuj-Maskutan ophiolites to well-known SSZ-systems such as the South Sandwich SSZ, and integrating with the existing literature on Inner Makran ophiolite belt we interpret the Fannuj-Maskutan ophiolite as a part of a major SSZ-basin opened in the Iranian cadomian crust and evolved during the Neotethys subduction under Central Iran
Raza, fobias e intolerancias. Num. 31 (2004) Vol. 11 mayo-agosto. Cuicuilco Revista de la Escuela Nacional de Antropología e Historia
No full text- Presentación, por Pablo Yankelevich - Dossier: - La singularidad de Auschwitz. Un debate sobre el uso público de la historia, por Enzo Traverso - El científico frente a la “crisis” de la civilización. Una aproximación a La incógnita del hombre de Alexis Carrel, por Andrés H. Reggiani - ¿Quiénes deben procrear? Los médicos eugenistas bajo el signo social (México, 1931-1940), por Marta Saade Granados - Ni blancos ni negros: mexicanos. El papel de la Patrulla Fronteriza estadounidense en la definición de una nueva categoría racial. 1924-1940, por Kelly Lytle Hernández - Nación y extranjería en el México revolucionario, por Pablo Yankelevich - Miscelánea: - El indigenismo como antropología aplicada, algunos apuntes a contrapunto, por José Palacios Ramírez - Una aproximación teórica a James C. Scott, por Mercedes Henríquez y España - Paradojas de la historia ejidal: El Llanito, Dolores Hidalgo, Guanajuato, 1930-1960, por Manola Sepúlveda Garza - Presencia de esterilidad: actores o sujetos en la actualidad, por Mayra L. Chávez-Courtois - Homosexualidad y género, por Magali Díaz Álvarez - Mente, intencionalidad y autopoiesis. Una heurística antropológica, por Jorge H. Flores Trejo
Una nueva categoría de urnas "acompañantes".. Anales del Instituto Nacional de Antropología e Historia. Num. 43 Tomo XIV (1961) Sexta Época (1939-1966)
No full textCaso, A. Las Estelas Zapotecas, Monografías del Museo Nacional de Arqueología, Historia y Etnografía. México, 1928.Caso, A. y Bernal, l. Urnas de Oaxaca. Memorias del lnstituto Nacional de Antropología e Historia. México, 1952.Leigh, H. Boletín de Estudios Oaxaqueños. Mexico City College, No. 2, marzo I, 1958 y No. 6, mayo 15. México, 1958
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