Metamorphic quantum dots: Quite different nanostructures

International Nuclear Information System (INIS)

Seravalli, L.; Frigeri, P.; Nasi, L.; Trevisi, G.; Bocchi, C.

2010-01-01

In this work, we present a study of InAs quantum dots deposited on InGaAs metamorphic buffers by molecular beam epitaxy. By comparing morphological, structural, and optical properties of such nanostructures with those of InAs/GaAs quantum dot ones, we were able to evidence characteristics that are typical of metamorphic InAs/InGaAs structures. The more relevant are: the cross-hatched InGaAs surface overgrown by dots, the change in critical coverages for island nucleation and ripening, the nucleation of new defects in the capping layers, and the redshift in the emission energy. The discussion on experimental results allowed us to conclude that metamorphic InAs/InGaAs quantum dots are rather different nanostructures, where attention must be put to some issues not present in InAs/GaAs structures, namely, buffer-related defects, surface morphology, different dislocation mobility, and stacking fault energies. On the other hand, we show that metamorphic quantum dot nanostructures can provide new possibilities of tailoring various properties, such as dot positioning and emission energy, that could be very useful for innovative dot-based devices.

International Uranium Resources Evaluation Project (IUREP) national favourability studies: Argentina

International Nuclear Information System (INIS)

1977-08-01

intruded by acidic rocks. The High Cordiilera, an area of 200,000 square kilometers in northwestern Argentina contains sedimentary, metamorphic, and igneous rocks that could be favorable although the difficult topography is a restrictive influence. The distribution of uranium mineralization in various sediments and other rock types over large areas of Argentina is suggestive of widespread favorability for uranium-ore formation. Inasmuch as uranium reserves plus potential are already estimated at close to 80,000 tons U 3 O 8 , and exploration has not been exhaustively conducted, ultimate resource potential might realistically be expected to fall in the 100,000 to 500,000 ton U 3 O 8 range

The magmatism and metamorphism at the Malayer area, Western Iran

Science.gov (United States)

Ahadnejad, V.; Valizadeh, M. V.; Esmaeily, D.

2009-04-01

The Malayer area is located in the NW-SE aligned Sanandaj-Sirjan metamorphic belt, western Iran and consists mainly of Mesozoic schists so-called Hamadan Phyllites, Jurassic to Tertiary intrusive rocks and related contact metamorphic aureoles, aplites and pegmatites. The Sanandj-Sirjan Zone is produced by oblique collisional event between Arabian plate and Central Iran microcontinent. Highest level of regional metamorphism in the area is greenschist facies and injection of felsic magmas is caused contact metamorphism. Magmatism is consist of a general northwest trend large felsic to intermediate intrusive bodies. The main trend of structural features i.e. faults, fractures and other structural features is NW-SE. The Malayer granitoid complex is ellipsoid in shape and has NW-SE foliation especially at the corners of the intrusions. Petrography of the magmatic rocks revealed recrystallization of quartz and feldspars, bending of biotite, and aligment of minerals paralle to the main trend of magmatic and metamorphic country rocks. These indicated that intrusion of felsic magma is coincide to the regional metamorphism and is syn-tectoinc. Non-extensive contact metamorphism aureoles and rareness of pegmatite and aplite in the area are interpreted as injection of felsic magmas into the high-strain metamorphic zone. The regional metamorphic rocks mainly consist of meta-sandstone, slate, phyllite, schist. These gray to dark metasedimentary rocks are consist of quartz, muscovite, turmaline, epidote, biotite and chlorite. Sheeted minerals form extended schistosity and study of porphyroblast-matrix relationships shows that injection of granitic magma into the country rocks is syn to post-tectonic. Syn-tectonic indicating porphyroblast growth synchronous with the development of the external fabric. The thermal contact area of the granite can be observed in the contact margin of granite and regional metamorphic rocks, where it produced hornfelses, andalusit-garnet schists and

The timing of tertiary metamorphism and deformation in the Albion-Raft River-Grouse Creek metamorphic core complex, Utah and Idaho

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Strickland, A.; Miller, E.L.; Wooden, J.L.

2011-01-01

The Albion-Raft River-Grouse Creek metamorphic core complex of southern Idaho and northern Utah exposes 2.56-Ga orthogneisses and Neoproterozoic metasedimentary rocks that were intruded by 32-25-Ma granitic plutons. Pluton emplacement was contemporaneous with peak metamorphism, ductile thinning of the country rocks, and top-to-thewest, normal-sense shear along the Middle Mountain shear zone. Monazite and zircon from an attenuated stratigraphic section in the Middle Mountain were dated with U-Pb, using a SHRIMP-RG (reverse geometry) ion microprobe. Zircons from the deformed Archean gneiss preserve a crystallization age of 2532 ?? 33 Ma, while monazites range from 32.6 ?? 0.6 to 27.1 ?? 0.6 Ma. In the schist of the Upper Narrows, detrital zircons lack metamorphic overgrowths, and monazites produced discordant U-Pb ages that range from 52.8 ?? 0.6 to 37.5 ?? 0.3 Ma. From the structurally and stratigraphically highest unit sampled, the schist of Stevens Spring, narrow metamorphic rims on detrital zircons yield ages from 140-110 Ma, and monazite grains contained cores that yield an age of 141 ??2 Ma, whereas rims and some whole grains ranged from 35.5 ?? 0.5 to 30.0 ?? 0.4 Ma. A boudinaged pegmatite exposed in Basin Creek is deformed by the Middle Mountains shear zone and yields a monazite age of 27.6 ?? 0.2 Ma. We interpret these data to indicate two periods of monazite and metamorphic zircon growth: a poorly preserved Early Cretaceous period (???140 Ma) that is strongly overprinted by Oligocene metamorphism (???32-27 Ma) related to regional plutonism and extension. ?? 2011 by The University of Chicago.

The post collisional metamorphic evolution from Ultra High Temperature to Amphibolite facies metamorphism in the Odesan area during the Triassic collision between the North and South China cratons.

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Lee, Byung Choon; Oh, Chang Whan; Kim, Tae Sung; Yi, Kee Wook

2015-04-01

The Odaesan Gneiss Complex (OGC) is the eastern end of the Hongseong-Odesan collision belt in Korean Peninsula which is the extension of the Dabie-Sulu collision belt between the North and South China blocks. The OGC mainly consists of banded and migmatitic gneiss with porphyritic granitoid and amphibolite. The banded gneiss can be subdivided into garnet-biotite and garnet-orthopyroxene banded gneisses. The highest metamorphic P/T conditions of the migmatitic and garnet-biotite banded gneiss were 760-820°C/6.3-7.2kbar and 810-840°C/7.2-7.8kbar respectively. On the other hand, the garnet-orthopyroxene banded gneiss records 940-950°C/10.5-10.7kbar that is corresponded to UHT metamorphic condition. These data indicate that the peak UHT metamorphic condition of the study area was preserved only within the garnet-orthopyroxene banded gneiss because its lower water content than other gneisses and UHT metamorphic mineral assemblage was completely replaced by the granulite facies metamorphism in other gneisses due to their higher water content than the garnet-orthopyroxene banded gneiss. Finally all gneisses experienced amphibolite facies retrograde metamorphism which is observed locally within rocks, such as garnet rim and surrounding area. The peak UHT metamorphism is estimated to occur at ca. 250-230 Ma using SHRIMP zircon U-Pb age dating and was caused by the heat supplied from asthenospheric mantle through the opening formed by slab break-off during early post collision stage. The calculated metamorphic conditions represent that geothermal gradient of the study area during the post collision stage was 86°C/kbar indicating the regional low-P/T metamorphic event. Besides the Triassic metamorphic age, two Paleoproterozoic metamorphic ages of ca. 1930 and 1886 Ma are also recognized by the SHRIMP age dating from the banded gneisses and Paleoproterozoic emplacement age of ca. 1847 Ma is identified from the porphyritic granitoid which formed in the within plate tectonic

Helosis (Balanophoraceae en Argentina Helosis (Balanophoraceae in Argentina

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José Luis Fontana

2006-07-01

Full Text Available Se cita por primera vez para Argentina Helosis cayennensis (Swartz Sprengel var. cayennensis en base a colecciones hechas por los autores en la Isla argentina de Apipé Grande, Ituzaingó, provincia de Corrientes. Se describe e ilustra la especie, el desarrollo de la planta y su estado de conservación. Esta cita de Helosis corresponde a un género nuevo para la flora argentina.Helosis cayennensis var. cayennensis is reported for the first time for Argentina. The species is described and ilustrated. Developement and ecology are also given. Helosis is also a new generic record for Argentina.

Regional metamorphism at extreme conditions: Implications for orogeny at convergent plate margins

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Zheng, Yong-Fei; Chen, Ren-Xu

2017-09-01

Regional metamorphism at extreme conditions refers either to Alpine-type metamorphism at low geothermal gradients of geothermal gradients of >30 °C/km. Extreme pressures refer to those above the polymorphic transition of quartz to coesite, so that ultrahigh-pressure (UHP) eclogite-facies metamorphism occurs at mantle depths of >80 km. Extreme temperatures refer to those higher than 900 °C at crustal depths of ≤80 km, so that ultrahigh-temperature (UHT) granulite-facies metamorphism occurs at medium to high pressures. While crustal subduction at the low geothermal gradients results in blueschist-eclogite facies series without arc volcanism, heating of the thinned orogenic lithosphere brings about the high geothermal gradients for amphibolite-granulite facies series with abundant magmatism. Therefore, UHP metamorphic rocks result from cold lithospheric subduction to the mantle depths, whereas UHT metamorphic rocks are produced by hot underplating of the asthenospheric mantle at the crustal depths. Active continental rifting is developed on the thinned lithosphere in response to asthenospheric upwelling, and this tectonism is suggested as a feasible mechanism for regional granulite-facies metamorphism, with the maximum temperature depending on the extent to which the mantle lithosphere is thinned prior to the rifting. While lithospheric compression is associated with subduction metamorphism in accretionary and collisional orogens, the thinned orogenic lithosphere undergoes extension due to the asthenospheric upwelling to result in orogen-parallel rifting metamorphism and magmatism. Thus, the rifting metamorphism provides a complement to the subduction metamorphism and its operation marks the asthenospheric heating of the orogenic lithosphere. Because of the partial melting and melt extraction of the lower continental crust, contemporaneous granite-migmatite-granulite associations may serve as a petrological indicator of rifting orogeny that is superimposed on

Recycling argon through metamorphic reactions: The record in symplectites

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McDonald, Christopher S.; Regis, Daniele; Warren, Clare J.; Kelley, Simon P.; Sherlock, Sarah C.

2018-02-01

The 40Ar/39Ar ages of metamorphic micas that crystallized at high temperatures are commonly interpreted as cooling ages, with grains considered to have lost 40Ar via thermally-driven diffusion into the grain boundary network. Recently reported laser-ablation data suggest that the spatial distribution of Ar in metamorphic micas does not always conform to the patterns predicted by diffusion theory and that despite high metamorphic temperatures, argon was not removed efficiently from the local system during metamorphic evolution. In the Western Gneiss Region (WGR), Norway, felsic gneisses preserve microtextural evidence for the breakdown of phengite to biotite and plagioclase symplectites during near isothermal decompression from c. 20-25 to c. 8-12 kbar at 700 °C. These samples provide an ideal natural laboratory to assess whether the complete replacement of one K-bearing mineral by another at high temperatures completely 'resets' the Ar clock, or whether there is some inheritance of 40Ar in the neocrystallized phase. The timing of the high-temperature portion of the WGR metamorphic cycle has been well constrained in previous studies. However, the timing of cooling following the overprint is still much debated. In-situ laser ablation spot dating in phengite, biotite-plagioclase symplectites and coarser, texturally later biotite yielded 40Ar/39Ar ages that span much of the metamorphic cycle. Together these data show that despite residence at temperatures of 700 °C, Ar is not completely removed by diffusive loss or during metamorphic recrystallization. Instead, Ar released during phengite breakdown appears to be partially reincorporated into the newly crystallizing biotite and plagioclase (or is trapped in fluid inclusions in those phases) within a close system. Our data show that the microtextural and petrographic evolution of the sample being dated provides a critical framework in which local 40Ar recycling can be tracked, thus potentially allowing 40Ar/39Ar dates

Emplacement and deformation of the Cerro Durazno Pluton delineates stages of the lower Paleozoic tectono-magmatic evolution in NW-Argentina

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Hongn, F.; Riller, U.

2003-04-01

Regional-scale transpression and transtension are considered to be important in the lower Paleozoic tectono-magmatic evolution of metamorphic and granitoid basement rocks of the southern central Andes. In order to test whether such kinematic changes affected Paleozoic basement rocks on the local scale, i.e. in the Eastern Cordillera of NW-Argentina, we performed a detailed field-based structural analysis of the 456 Ma granitoid Cerro Durazno pluton (CDP). The results of our analysis point to the following stages in the geodynamic evolution of this area: (1) Metamorphism and deformation of Neoproterozoic-Paleozoic basement rocks occurred at high T and low to medium P prior to emplacement of the CDP. This lead to the formation of schists and migmatites characterized by pervasive planar and linear mineral shape fabrics and the growth of andalusite, cordierite and fibrolite. (2) Magmatic foliation in the CDP is defined by the shape-preferred orientation of euhedral feldspar phenocrysts and microgranitoid enclaves. These fabrics are concordant to the NE-SW striking intrusive contact with migmatitic host rocks. The lack of submagmatic or high-T solid-state fabrics in the CDP may indicate that cooling and solidification of granitoid magma was not accompanied by regional deformation. Alternatively, emplacement of granitoid magma may have been facilitated by the creation of open space at mid-crustal level induced by regional deformation. (3) Ductile deformation under greenschist metamorphic conditions overprinted magmatic fabrics of the CDP. This is evident by NW-SE striking metamorphic foliation surfaces transecting magmatic shape fabrics at high angles. During this deformation, the pluton was thrust on a SW-dipping shear zone toward the NE over low-grade metamorphic host rocks which lead to a condensation of metamorphic isograds in the host rocks. Ages of strained pegmatitic dikes indicate that this deformation occurred at about 430 Ma. In summary, the difference in age

Argentina.

Science.gov (United States)

1986-06-01

This discussion of Argentina covers geography, the people, history and political conditions, government, economy, foreign relations, and relations between the US and Argentina. In 1985, the population of Argentina was estimated to be 30.6 million with an estimated annual growth rate of 1.5%. The infant mortality rate is 34.1/1000, and life expectancy is 70.2 years. Argentina, which shares land borders with Bolivia, Brazil, Chile, Paraguay, and Uruguay, is bounded by the Atlantic and the Antarctic Oceans. Descendants of Italian and Spanish immigrants predominate in Argentina, but many trace their origins to British and West and East European ancestors. In recent years, there has been a substantial influx of immigrants from neighboring Latin American countries. The native Indian population, estimated to be 50,000, is concentrated in the peripheral provinces of the north, northwest, and south. What is now Argentina was discovered in 1516 by the Spanish navigator Juan de Solia. The formal declaration of independence from Spain was made on July 9, 1816. In the late 19th century, 2 forces worked to create the modern Argentine nation: the introduction of modern agricultural techniques and the integration of Argentina into the world economy. Argentina has impressive human and natural resources, but political conflict and uneven economic performance since World War II have impeded full realization of its considerable potential. Yet, it is one of the wealthiest countries in Latin America. Among the reasons for the military coup of March 1976 was the deteriorating economy, caused by declining production and rampant inflation. Under the leadership of the Minister of the Economy, the military government focused attention on those immediate problems, and, in 1978, embarked on a new development strategy focusing on the establishment of a free market economy. There was little improvement in the economy, and a new economic plan was introduced in 1985 which has capped inflation by

Tectono-metamorphic evolution and magmatic processes in the thermo-metamorphic aureole of the Monte Capanne pluton (Elba Island, Northern Tyrrhenian Sea, Italy).

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Morelli, M.; Pandeli, E.; Principi, G.

2003-04-01

Introduction In this work we present new structural and petrographic data collected in the thermo-metamorphic aureole of Monte Capanne (western Elba Island) and its metamorphic evolution. In the western Elba Island the Monte Capanne monzogranitic body (ca. 7 Ma) and its thermo-metamorphic aureole crop out. At least two different tectonic units can be distinguished: the Punta Le Tombe Unit, weak re-crystallized, and the Punta Nera Unit. In the latter one the re-crystallization is strong and a pre-intrusion tectono-metamorphic framework is evident (Morelli et al., 2002). The latter is mainly constituted by thermo-metamorphosed meta-ophiolites and meta-sedimentary successions previously correlated by Barberi et al. (1969) with the un-metamorphic ones (Complex IV and V of Trevisan, 1950) cropping out in the central-eastern Elba. According to Perrin (1975) and Reutter &Spohn (1982) a pre-intrusion tectono-metamorphic framework was recognized into such rocks. As suggested by Daniel &Jolivet (1995) complex relationships between metamorphic evolution and magmatic events are also recognizable. Geological Data The Punta Nera Unit crops out all around the Monte Capanne magmatic body and the primary contact with the underlying granitoid is somewhere preserved. This unit, strongly re-crystallized and locally crosscut by aplitic and porphyritic dikes, is represented by (Coli &Pandeli, 1997; Morelli, 2000) tectonized meta-serpentinites, meta-gabbros with rodingitic dikes, rare meta-basalts and meta-ophicalcites, meta-cherts, marbles, cherty meta-limestones, phyllites and meta-limestones with rare meta-arenites intercalations. A "pre-magmatic" tectono-metamorphic framework of this unit is well evident only in its meta-sedimentary portion. The meta-sediments are deformed by syn-metamorphic isoclinal folds caractherized by N-S trending axes, west dipping axial planes and easternward vergence. A later folding and flattening event clearly post-dated the above said folds and associated

Fluids in metamorphic rocks

NARCIS (Netherlands)

Touret, J.L.R.

2001-01-01

Basic principles for the study of fluid inclusions in metamorphic rocks are reviewed and illustrated. A major problem relates to the number of inclusions, possibly formed on a wide range of P-T conditions, having also suffered, in most cases, extensive changes after initial trapping. The

Metamorphic and geochronogical study of the Triassic El Oro metamorphic complex, Ecuador: Implications for high-temperature metamorphism in a forearc zone

Science.gov (United States)

Riel, N.; Guillot, S.; Jaillard, E.; Martelat, J.-E.; Paquette, J.-L.; Schwartz, S.; Goncalves, P.; Duclaux, G.; Thebaud, N.; Lanari, P.; Janots, E.; Yuquilema, J.

2013-01-01

In the forearc of the Andean active margin in southwest Ecuador, the El Oro metamorphic complex exhibits a well exposed tilted forearc section partially migmatized. We used Raman spectroscopy on carbonaceous matter (RSCM) thermometry and pseudosections coupled with mineralogical and textural studies to constrain the pressure-temperature (P-T) evolution of the El Oro metamorphic complex during Triassic times. Our results show that anatexis of the continental crust occurred by white-mica and biotite dehydration melting along a 10 km thick crustal domain (from 4.5 to 8 kbar) with increasing temperature from 650 to 700 °C. In the biotite dehydration melting zone, temperature was buffered at 750-820 °C in a 5 km thick layer. The estimated average thermal gradient during peak metamorphism is of 30 °C/km within the migmatitic domain can be partitioned into two apparent gradients parts. The upper part from surface to 7 km depth records a 40-45 °C/km gradient. The lower part records a quasi-adiabatic geotherm with a 10 °C/km gradient consistent with an isothermal melting zone. Migmatites U-Th-Pb geochronology yielded zircon and monazite ages of 229.3 ± 2.1 Ma and 224.5 ± 2.3 Ma, respectively. This thermal event generated S-type magmatism (the Marcabeli granitoid) and was immediately followed by underplating of the high-pressure low-temperature (HP-LT) Arenillas-Panupalí unit at 225.8 ± 1.8 Ma. The association of high-temperature low-pressure (HT-LP) migmatites with HP-LT unit constitutes a new example of a paired metamorphic belt along the South American margin. We propose that in addition to crustal thinning, underplating of the Piedras gabbroic unit before 230 Ma provided the heat source necessary to foster crustal anatexis. Furthermore, its MORB signature shows that the asthenosphere was involved as the source of the heat anomaly. S-type felsic magmatism is widespread during this time and suggests that a large-scale thermal anomaly affected a large part of the

The discovery of hornblende-garnet-zoisite hornfels in the metamorphic basement of Xiangshan uranium ore field

International Nuclear Information System (INIS)

Jiang Zhenpin; Dong Yongjie; Yu Jianfa; Hu Rongquan; Wu Shuilin

2007-01-01

Some vein rocks are found among mica schist in the metamorphic rock area of the Xiangshan uranium ore field. They are petrologically denominated as hornblende-garnet-zoisite hornfels. The primitive rocks are basic vein rocks. The hornfels are formed under thermal metamorphism with the temperature about 640 degree C and belong to low-pressure faces. This is closed to the form condition of EarlyMiddle Proterozoic metamorphic rocks in the area. The metamorphism forming the hornfels means that the Early-Middle Proterozoic metamorphic rocks was superimposed to another thermal metamorphism and produced the second phase metamorphic minerals such as staurolite, almandine and biotite. The lattice of the second phase metamorphic mineral developed continuously with the first phase minerals. The overlapping metamorphism made the first phase metamorphic mineral suffer recrystallization, auto purification and idiomorphism. The discovery of hornfelsed basic rock veins discloses that strong geologic process with the activity of fault, magma and metamorphism were still taken placed in Paleozoic era within the metamorphic basement of the Xiangshan uranium ore field. (authors)

Syn-extensional plutonism and peak metamorphism in the albion-raft river-grouse creek metamorphic core complex

Science.gov (United States)

Strickland, A.; Miller, E.L.; Wooden, J.L.; Kozdon, R.; Valley, J.W.

2011-01-01

The Cassia plutonic complex (CPC) is a group of variably deformed, Oligocene granitic plutons exposed in the lower plate of the Albion-Raft River- Grouse Creek (ARG) metamorphic core complex of Idaho and Utah. The plutons range from granodiorite to garnet-bearing, leucogranite, and during intrusion, sillimanite- grade peak metamorphism and ductile attenuation occurred in the country rocks and normal-sense, amphibolite-grade deformation took place along the Middle Mountain shear zone. U-Pb zircon geochronology from three variably deformed plutons exposed in the lower plate of the ARG metamorphic core complex revealed that each zircon is comprised of inherited cores (dominantly late Archean) and Oligocene igneous overgrowths. Within each pluton, a spread of concordant ages from the Oligocene zircon overgrowths is interpreted as zircon recycling within a long-lived magmatic system. The plutons of the CPC have very low negative whole rock ??Nd values of -26 to -35, and initial Sr values of 0.714 to 0.718, consistent with an ancient, crustal source. Oxygen isotope ratios of the Oligocene zircon overgrowths from the CPC have an average ??18O value of 5.40 ?? 0.63 permil (2SD, n = 65) with a slight trend towards higher ??18O values through time. The ??18O values of the inherited cores of the zircons are more variable at 5.93 ?? 1.51 permil (2SD, n = 29). Therefore, we interpret the plutons of the CPC as derived, at least in part, from melting Archean crust based on the isotope geochemistry. In situ partial melting of the exposed Archean basement that was intruded by the Oligocene plutons of the CPC is excluded as the source for the CPC based on field relationships, age and geochemistry. Correlations between Ti and Hf concentrations in zircons from the CPC suggest that the magmatic system may have become hotter (higher Ti concentration in zircon) and less evolved (lower Hf in zircon concentration) through time. Therefore, the CPC represents prolonged or episodic magmatism

Histamine is a modulator of metamorphic competence in Strongylocentrotus purpuratus (Echinodermata: Echinoidea

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Sutherby Josh

2012-04-01

Full Text Available Abstract Background A metamorphic life-history is present in the majority of animal phyla. This developmental mode is particularly prominent among marine invertebrates with a bentho-planktonic life cycle, where a pelagic larval form transforms into a benthic adult. Metamorphic competence (the stage at which a larva is capable to undergo the metamorphic transformation and settlement is an important adaptation both ecologically and physiologically. The competence period maintains the larval state until suitable settlement sites are encountered, at which point the larvae settle in response to settlement cues. The mechanistic basis for metamorphosis (the morphogenetic transition from a larva to a juvenile including settlement, i.e. the molecular and cellular processes underlying metamorphosis in marine invertebrate species, is poorly understood. Histamine (HA, a neurotransmitter used for various physiological and developmental functions among animals, has a critical role in sea urchin fertilization and in the induction of metamorphosis. Here we test the premise that HA functions as a developmental modulator of metamorphic competence in the sea urchin Strongylocentrotus purpuratus. Results Our results provide strong evidence that HA leads to the acquisition of metamorphic competence in S. purpuratus larvae. Pharmacological analysis of several HA receptor antagonists and an inhibitor of HA synthesis indicates a function of HA in metamorphic competence as well as programmed cell death (PCD during arm retraction. Furthermore we identified an extensive network of histaminergic neurons in pre-metamorphic and metamorphically competent larvae. Analysis of this network throughout larval development indicates that the maturation of specific neuronal clusters correlates with the acquisition of metamorphic competence. Moreover, histamine receptor antagonist treatment leads to the induction of caspase mediated apoptosis in competent larvae. Conclusions We

Low-grade metamorphism of Cambro-Ordovician successions in the Famatina belt, Southern-Central Andes: Burial-inversion history linked to the evolution of the proto-Andean Gondwana margin Metamorfismo de bajo grado de sucesiones cambro-ordovícicas en el cinturón del Famatina, Andes Centrales de Argentina: Historia de enterramiento-exhumación ligada a la evolución del margen proto-andino de Gondwana

Directory of Open Access Journals (Sweden)

Gilda Collo

2011-07-01

Full Text Available The metamorphic P-T conditions of low-grade units from the Famatina belt, Central Andes of Argentina, were estimated through petrography, X-ray diffraction, and electron microscopy. For the Middle-Upper Cambrian Negro Peinado Formation a tectono-metamorphic event associated with intense intrafoliar folding, with estimated temperatures between 290 and 400°C (KIcis: 0.16-0.27A°29, biotite blastesis and compositional homogeneity in dioctahedral micas and intermediate pressure conditions (white mica b parameter: 9.010Á-9.035Á, was recognized. The Achavil Formation (Middle-Upper Cambrian presents a main metamorphic event associated with temperatures between 200 and 290°C (KIcis: 0.26-0.41A°29 and intermediate- to low-pressure conditions (white mica b parameter values: 8.972Á-9.017Á. Some illitic substitution in dioctahedral micas also indicates lower metamorphic grade than the Negro Peinado Formation. For Upper Cambrian to Middle Ordovician sequences a burial metamorphic pattern, with a progressive decrease in metamorphic grade from Volcancito Formation to Cerro Morado Group (ca. 490-465 Ma; KIcis: 0.31-0.69A°29 and absence of tendency changes linked to strati-graphic discontinuities was proposed. Mica and chlorite are the main phyllosilicates in the oldest units, while Ilt/ Sme (R3 mixed-layer is almost the only one in the youngest. White mica b parameter indicates intermediate- to low-pressure conditions for all these sequences. This burial metamorphic pattern presents a marked break as the youngest Ordovician unit (La Aguadita Formation, after ca. 452 Ma records higher metamorphic conditions (IKcis: 0.28-0.19A°29 than units from the Ordovician arc, with estimated temperatures between 270 and 330°C and intermediate-pressure conditions. Our results indicate that basin contraction and inversion processes related to the Ordovician Ocloyic Orogeny involved at least two well-discriminated and not superposed metamorphic episodes in this region

New U-Pb ages in the Diablillos Intrusive Complex, Southern Puna, Argentina: A long magmatic event in the Paleozoic Arc, SW Gondwana

International Nuclear Information System (INIS)

Ortiz, Agustin; Hauser, Natalia

2015-01-01

The Puna geological region comprises Salta, Jujuy and Catamarca provinces, northwestern Argentina. This 4000 meter above sea level high-plateau region lies between the Central Argentinian Andes. The Puna basement in the central Andes consists of Proterozoic–Paleozoic metamorphic rocks and granitoids. Diverse authors, proposed different models to explain the origin of the basement, where two orogenic events are recognized: the Pampean (Upper Precambrian–Lower Cambrian) and Famatinian (Upper Cambrian–Lower Silurian) (e.g. Ramos et al., 1986; Ramos, 1988; Loewy et al., 2004; for opposite points of view see Becchio et al., 1999; Bock et al., 2000; Buttner et al., 2005). Hence, Lucassen et al. (2000) proposed for the Central Andean basement, an evolution in a mobile belt, where the Pampean and Famatinian cycles are not distinct events but, they are one single, non-differentiable event from 600 to 400 Ma. The mobile belt culminated in low-P/ high-T metamorphism at approximately 525-500 Ma. Then, these were followed by a long-lasting high-thermal gradient regime in the mid-crust until Silurian times. Becchio et al., (2011) defined the Diablillos Intrusive Complex (CID, by its Spanish name), emplaced in the Inca Viejo Range. This range splits the Salares Ratones-Centenario with the Salar Diablillos (Fig.1). This Complex is located in the Eastern Magmatic Belt, Southern Puna, Argentina. Here we present new zircons U-Pb ages by LA-MC-ICPMS in the Diablillos Intrusive Complex, contributing to understanding the magmatic event in the lower Paleozoic arc, SW Gondwana. (author)

New U-Pb ages in the Diablillos Intrusive Complex, Southern Puna, Argentina: A long magmatic event in the Paleozoic Arc, SW Gondwana

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Ortiz, Agustin; Hauser, Natalia [Universidade de Brasilia (UnB), DF (Brazil). Instituto de Geociencias. Lab. de Geocronologia; Becchio, Raul; Nieves, Alexis; Suzano, Nestor [Universidad Nacional de Salta (UNSa)-CONICET, Salta (Argentina)

2015-07-01

The Puna geological region comprises Salta, Jujuy and Catamarca provinces, northwestern Argentina. This 4000 meter above sea level high-plateau region lies between the Central Argentinian Andes. The Puna basement in the central Andes consists of Proterozoic–Paleozoic metamorphic rocks and granitoids. Diverse authors, proposed different models to explain the origin of the basement, where two orogenic events are recognized: the Pampean (Upper Precambrian–Lower Cambrian) and Famatinian (Upper Cambrian–Lower Silurian) (e.g. Ramos et al., 1986; Ramos, 1988; Loewy et al., 2004; for opposite points of view see Becchio et al., 1999; Bock et al., 2000; Buttner et al., 2005). Hence, Lucassen et al. (2000) proposed for the Central Andean basement, an evolution in a mobile belt, where the Pampean and Famatinian cycles are not distinct events but, they are one single, non-differentiable event from 600 to 400 Ma. The mobile belt culminated in low-P/ high-T metamorphism at approximately 525-500 Ma. Then, these were followed by a long-lasting high-thermal gradient regime in the mid-crust until Silurian times. Becchio et al., (2011) defined the Diablillos Intrusive Complex (CID, by its Spanish name), emplaced in the Inca Viejo Range. This range splits the Salares Ratones-Centenario with the Salar Diablillos (Fig.1). This Complex is located in the Eastern Magmatic Belt, Southern Puna, Argentina. Here we present new zircons U-Pb ages by LA-MC-ICPMS in the Diablillos Intrusive Complex, contributing to understanding the magmatic event in the lower Paleozoic arc, SW Gondwana. (author)

Isotopic studies of marbles in the Sanbagawa metamorphic terrain, central Shikoku, Japan

International Nuclear Information System (INIS)

Wada, Hideki; Enami, Masaki; Yanagi, Takeru.

1984-01-01

Carbon, oxygen and strontium isotopic studies were carried out on marbles occurring in crystalline schists and epidote amphibolites of the Sanbagawa metamorphic terrain, central Shikoku, Japan, in order to estimate metamorphic temperatures and to elucidate their origin. Carbon isotopic fractionation between calcite and graphite shows the metamorphic temperature of 460 deg C at the transitional part between the garnet and albite-biotite zones. Marbles are isotopically classified into two groups. (1) some marbles in epidote amphibolite masses show characteristically negative delta 13 C values and low 87 Sr/ 86 Sr ratios. These marbles are interpreted as have been derived from magmatic or deep-seated carbonates. (2) marbles collected from the crystalline schists and from the marginal part of epidote amphibolite masses, have high 87 Sr/ 86 Sr ratios and delta 13 C values similar to those of typical sedimentary carbonates. They were probably derived from sedimentary carbonates and/or carbonates re-equilibrated with metamorphic fluid segregated from crystalline schists during the Sanbagawa metamorphism. (author)

Uranium and thorium migration under dislocative metamorphism

International Nuclear Information System (INIS)

Titov, V.K.; Bilibina, T.V.; Dashkova, A.D.; Il'in, V.K.; Makarova, L.I.; Shmuraeva, L.Ya.

1978-01-01

Investigated were peculiarities of uranium and thorium behaviour in the process of dislocation metamorphism on the basis of regional fracture zones of early-proterozoic embedding of Ukrainian, Aldan and Baltic shields. The studied zones correspond to tectonite of green-shale and almandin-amphibolite facies of regional metamorphism according to mineral associations. The most peculiar feature of the tectonites of green-shale facies is uranium presence in migrationally able forms, which can be involved afterwards into the ore process by hydrothermal solutions. Adsorved forms of uranium on the crystal surface or separate grains and in the cracks, as well as microinclusions of uranium minerals, selectively timed to mineral structure defects prevail among easily mobile uranium compounds. Dissolved uranium is present, evidently in gas-liquid inclusions in minerals and pore waters. There forms of uranium presence are peculiar for epidote-chlorite mylonites, as well as cataclasites and diaphthorites related to them by blastomylonites of almandin-amphibolite facies. Wide range of manifestation of this process, caused by multikilometer extension of deep fracture zones permit to consider the formations of green-shale facies of dislocation metamorphism as one of the main uranium sources in deposit formation in different uranium-ore associations different age

Shear heating and metamorphism in subduction zones, 1. Thermal models

Science.gov (United States)

Kohn, M. J.; Castro, A. E.; Spear, F. S.

2017-12-01

Popular thermal-mechanical models of modern subduction systems are 100-500 °C colder at c. 50 km depth than pressure-temperature (P-T) conditions determined from exhumed metamorphic rocks. This discrepancy has been ascribed by some to profound bias in the rock record, i.e. metamorphic rocks reflect only anomalously warm subduction, not normal subduction. Accurately inferring subduction zone thermal structure, whether from models or rocks, is crucial for predicting depths of seismicity, fluid release, and sub-arc melting conditions. Here, we show that adding realistic shear stresses to thermal models implies P-T conditions quantitatively consistent with those recorded by exhumed metamorphic rocks, suggesting that metamorphic rock P-T conditions are not anomalously warm. Heat flow measurements from subduction zone fore-arcs typically indicate effective coefficients of friction (µ) ranging from 0.025 to 0.1. We included these coefficients of friction in analytical models of subduction zone interface temperatures. Using global averages of subducting plate age (50 Ma), subduction velocity (6 cm/yr), and subducting plate geometry (central Chile), temperatures at 50 km depth (1.5 GPa) increase by c. 200 °C for µ=0.025 to 700 °C for µ=0.1. However, at high temperatures, thermal softening will reduce frictional heating, and temperatures will not increase as much with depth. Including initial weakening of materials ranging from wet quartz (c. 300 °C) to diabase (c. 600 °C) in the analytical models produces concave-upward P-T distributions on P-T diagrams, with temperatures c. 100 to 500 °C higher than models with no shear heating. The absolute P-T conditions and concave-upward shape of the shear-heating + thermal softening models almost perfectly matches the distribution of P-T conditions derived from a compilation of exhumed metamorphic rocks. Numerical models of modern subduction zones that include shear heating also overlap metamorphic data. Thus, excepting the

Metamorphic history and age of aluminous gneisses of the Belomorian belt of the Baltic shield

International Nuclear Information System (INIS)

Bibikova, E.V.; Borisova, E.Yu.; Makarov, V.A.; Drugova, G.M.

1997-01-01

Metamorphic conditions and age are determined for the early metamorphic stage of aluminous gneisses in the Chupa nappe in the Belomorian Mobile Belt. The granulite-facies metamorphic conditions during Late Archean time are determined based on the composition of garnet and biotie from the metapelites. The early metamorphic stage was dated at 2860 ± 30 Ma based on the U-Pb systematics of granulitic zircon from the metapelites. The U-Pb isotopic system of the zircon was strongly affected by Svecogennian metamorphism (at 1750 Ma). The geodynamic evolution of the Belomorian Mobile Belt is discussed in light of the data of this work

Metamorphic evolution of the eastern part

Directory of Open Access Journals (Sweden)

Faryad Shah Wali

1999-06-01

Full Text Available The Inner to Central parts of the Western Carpathians consist of several tectonic units that provide unique opportunity to investigate Alpine and Pre-Alpine tectonothermal evolution in the Western Carpathians. Lithological and geochemical composition of sedimentary and igneous rocks indicate the presence of Alpine-Meliata and Pre-Alpine Rakovec suture zones. The Meliata blueschists are the only evidence of subducted Triassic Meliata-Hallstatt oceanic basin and adjacent continental wedge which occurred during the Jurassic time. These processes were followed by the Cretaceous collision that suffered not only the Gemer but also the Vepor Belts. Since Alpine and Variscan metamorphism occurred in most tectonic units under similar pressure and/or temperature conditions, for reconstruction of Alpine development is necessary to understand Pre-Alpine history of each tectonic unit. The Field Meeting is aimed to comprehend Alpine and Pre-Alpine tectonothermal evolution in the eastern parts of the Western Carpathians with a special respect to subduction and exhumation history of the Jurassic Meliata blueschists, as well as of Cretaceous collision in the Western Carpathians. In order to clear metamorphic characteristic and geological position of each unit a brief outline on structure and metamorphism of the Central Western Carpathians is given in the excursion guide. The manuscript of this work was improved by helpful suggestions of S. Jacko, D. Plašienka and M. Janák. This work was supported by Slovak Academic Agency, project WEGA-1/5003/98

Stable isotope study of serpentinization and metamorphism in the Highland Border Suite, Scotland, UK

Energy Technology Data Exchange (ETDEWEB)

Ikin, N.P. (University Coll., Cardiff (UK)); Harmon, R.S. (Southern Methodist Univ., Dallas, TX (USA))

1983-02-01

D/H and /sup 18/O//sup 16/O ratios have been measured for whole-rock samples and mineral separates from the mafic and ultramafic rocks of the Cambro-Ordovician Highland Border Suite. The H- and O-isotopic compositions of these rocks record individual stages in a relatively complex 500 Myr old hydrothermal/ metamorphic history. Lizardite serpentinites record a premetamorphic history and indicate that parent harzburgites, dunites, and pyroxenites were serpentinized through low-temperature interaction with meteoric waters during cooling. The other rocks of the Highland Border Suite record subsequent interaction with metamorphic fluids. Amphibolite facies hornblende schists were produced through thrust-related metamorphism of spilitic pillow lavas. During dehydration, D-enriched fluids were driven off from the spilites thus leaving the hornblende schists to equilibrate with a relatively D-depleted internal fluid reservoir. The expelled D-enriched fluids may have mixed with more typical Dalradian metamorphic waters which then exchanged with the remaining mafic rocks and lizardite serpentinites during greenschist facies regional metamorphism to produce antigorite serpentinites and greenschist metaspilites with similar H- and O-isotopic compositions. Serpentinites which have been only partially metamorphosed show intermediate H-isotopic compositions between that of metamorphic antigorite and non-metamorphic lizardite end members.

Pathway to 50% Efficient Inverted Metamorphic Concentrator Solar Cells

Energy Technology Data Exchange (ETDEWEB)

Geisz, John F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Steiner, Myles A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jain, Nikhil [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schulte, Kevin L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); France, Ryan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McMahon, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Perl, Emmett [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Horowitz, Kelsey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Friedman, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-06

Series-connected five (5J) and six junction (6J) concentrator solar cell strategies have the realistic potential to exceed 50% efficiency to enable low-cost CPV systems. We propose three strategies for developing a practical 6J device. We have overcome many of the challenges required to build such concentrator solar cell devices: We have developed 2.1 eV AlGaInP, 1.7 eV AlGaAs, and 1.7 eV GaInAsP junctions with external radiative efficiency greater than 0.1%. We have developed a transparent tunnel junction that absorbs minimal light intended for the second junction yet resists degradation under thermal load. We have developed metamorphic grades from the GaAs to the InP lattice constant that are transparent to sub-GaAs bandgap light. We have grown and compared low bandgap junctions (0.7eV - 1.2 eV) using metamorphic GaInAs, metamorphic GaInAsP, and GaInAsP lattice-matched to InP. And finally, we have demonstrated excellent performance in a high voltage, low current 4 junction inverted metamorphic device using 2.1, 1.7, 1.4, and 1.1 eV junctions with over 8.7 mA/cm2 one-sun current density that operates up to 1000 suns without tunnel junction failure.

Isotopic evidence for two neoproterozoic high-grade metamorphic events in the Brazilia belt

International Nuclear Information System (INIS)

Pimentel, Marcio Martins; Fuck, Reinhardt Adolfo; Piuzanna, Danielle; Moraes, Renato de; Gioia, Simone Maria C.L

2001-01-01

The Brasilia Belt is part of a Brasiliano/Pan African orogen developed between the Amazon and Sao Francisco cratons. The stabilization of the belt occurred after the last metamorphic event at ca. 620 Ma. There has been increasing geochronological evidence, however, for an older Neoproterozoic metamorphic event at ca. 780 Ma, observed mainly in high grade rocks of three large mafic-ultramafic complexes in the northern part of the belt. In this study we present: (i) new U-Pb and Sm-Nd geochronological data, (ii) a review of the existing metamorphic ages in the Brasilia Belt, and (iii) a discussion on the tectonic model to explain the two Neoproterozoic metamorphic ages (au)

Magmatism and mineralization ages from northeast area of La Sierra de San Luis, Argentina

International Nuclear Information System (INIS)

Ulacco, Jose H

2001-01-01

Three igneous rock groups, characterized as pre, sin and post-kinematics, have intruded the crystalline basement of Sierra de San Luis, Argentina. The ore deposits are associated with Devonian to Carboniferous epizonal granite stocks and batholiths in an area underlain by metamorphic rocks. This granitoids are characterized as post-kinematics magmatism. Model lead ages on the ore deposits (338,8 - 292,1 Ma) are strongly supported by K-Ar ages of the intrusives. The bulk of the north Sierra de San Luis ore deposits are genetically related to late Carboniferous granite plutons. The ore bodies are tungsten veins with greisen envelopes, lead veins, epithermal fluorite veins and REE and Th deposit. A generalized scheme of ore bodies related to granites is proposed. The ore deposits and their lithotectonic setting are characteristic of Gondwana metallogenetic Epoch in the Sierra de San Luis (au)

Measuring metamorphic history of unequilibrated ordinary chondrites

International Nuclear Information System (INIS)

Sears, D.W.; Grossman, J.N.; Melcher, C.L.; Ross, L.M.; Mills, A.A.

1980-01-01

A thermoluminescence sensitivity technique is used to give a new measurement of the degree of metamorphism of unequilibrated ordinary chondrites. Consequently the petrological assignment of these meteorites is modified. (author)

Pressure-temperature evolution of Neoproterozoic metamorphism in the Welayati Formation (Kabul Block), Afghanistan

Science.gov (United States)

Collett, Stephen; Faryad, Shah Wali

2015-11-01

The Welayati Formation, consisting of alternating layers of mica-schist and quartzite with lenses of amphibolite, unconformably overlies the Neoarchean Sherdarwaza Formation of the Kabul Block that underwent Paleoproterozoic granulite-facies and Neoproterozoic amphibolite-facies metamorphic events. To analyze metamorphic history of the Welayati Formation and its relations to the underlying Sherdarwaza Formation, petrographic study and pressure-temperature (P-T) pseudosection modeling were applied to staurolite- and kyanite-bearing mica-schists, which crop out to the south of Kabul City. Prograde metamorphism, identified by inclusion trails and chemical zonation in garnet from the micaschists indicates that the rocks underwent burial from around 6.2 kbar at 525 °C to maximum pressure conditions of around 9.5 kbar at temperatures of around 650 °C. Decompression from peak pressures under isothermal or moderate heating conditions are indicated by formation of biotite and plagioclase porphyroblasts which cross-cut and overgrow the dominant foliation. The lack of sillimanite and/or andalusite suggests that cooling and further decompression occurred in the kyanite stability field. The results of this study indicate a single amphibolite-facies metamorphism that based on P-T conditions and age dating correlates well with the Neoproterozoic metamorphism in the underlying Sherdarwaza Formation. The rocks lack any paragenetic evidence for a preceding granulite-facies overprint or subsequent Paleozoic metamorphism. Owing to the position of the Kabul Block, within the India-Eurasia collision zone, partial replacement of the amphibolite-facies minerals in the micaschist could, in addition to retrogression of the Neoproterozoic metamorphism, relate to deformation associated with the Alpine orogeny.

Origin and geodynamic significance of the early Mesozoic Weiya LP and HT granulites from the Chinese Eastern Tianshan

Science.gov (United States)

Mao, Ling-Juan; He, Zhen-Yu; Zhang, Ze-Ming; Klemd, Reiner; Xiang, Hua; Tian, Zuo-Lin; Zong, Ke-Qing

2015-12-01

The Chinese Tianshan in the southwestern part of the Central Asian Orogenic Belt (CAOB) is characterized by a variety of high-grade metamorphic rocks, which provide critical constraints for understanding the geodynamic evolution of the CAOB. In this paper, we present detailed petrological and zircon U-Pb geochronological studies of the Weiya low-pressure and high-temperature (LP-HT) granulites of the Chinese Eastern Tianshan. These granulites were previously considered to be a product of a regional metamorphic orogenic event. Due to different bulk-rock chemistries the Weiya granulites, which occur as lenses within the contact metamorphic aureole of the Weiya granitic ring complex, have a variety of felsic-pelitic and mafic granulites with different textural equilibrium mineral assemblages including garnet-cordierite-sillimanite-bearing granulites, cordierite-sillimanite-bearing granulites, cordierite-orthopyroxene-bearing granulites, and orthopyroxene-clinopyroxene-bearing granulites. Average P-T thermobarometric calculations and conventional geothermobarometry indicates that the Weiya granulites underwent early prograde metamorphism under conditions of 600-650 °C at 3.2-4.2 kbar and peak metamorphism of 750-840 °C at 2.9-6.3 kbar, indicating a rather high geothermal gradient of ca. 60 °C/km. Zircon U-Pb LA-ICP-MS dating revealed metamorphic ages between 244 ± 1 to 237 ± 3 Ma, which are in accordance with the crystallization age of the Weiya granitic ring complex. We suggest that the formation of the Weiya granulites was related to contemporaneous granitic magmatism instead of a regional metamorphic orogenic event. In addition, a Late Devonian metamorphic age of ca. 380 Ma was recorded in zircon mantle domains from two pelitic samples which is consistent with the metamorphic age of the Xingxingxia metamorphic complex in the Chinese Eastern Tianshan. This suggests that the mantle domains of the zircon grains of the Weiya granulites probably formed during the

Development of III-Sb metamorphic DBR membranes on InP for vertical cavity laser applications

Science.gov (United States)

Addamane, S. J.; Mansoori, A.; Renteria, E. J.; Dawson, N.; Shima, D. M.; Rotter, T. J.; Hains, C. P.; Dawson, L. R.; Balakrishnan, G.

2016-04-01

Sb-based metamorphic DBR membranes are developed for InP-based vertical cavity laser applications. The reflectivity of the metamorphic DBR membrane is compared to the reflectivity of a lattice-matched DBR to characterize the optical quality of the DBR membrane. The metamorphic interface between InP and the III-antimonides is found to degrade the reflectivity of the DBR. Therefore, the growth temperature for the metamorphic DBR is optimized in order to obtain highly reflective (>99.8%) III-Sb thin-film membranes.

Tectono-metamorphic evolution of the Chinese Altai, central Asia: new insights from microstructures

Science.gov (United States)

Jiang, Yingde; Zhang, Jian; Schulmann, Karel; Sun, Min; Zhao, Guochun

2013-04-01

The Altai Orogen, extending from Russia, through northeast Kazakhstan and northwest China, to western and southern Mongolia, occupies a pivotal position in understanding the accretionary process of the Central Asian Orogenic Belt and has drawn much attention in recent years. However, its orogenic evolution remains poorly constrained, because previous studies were mainly focused on the geochronological and geochemical signatures and much less work has been done on metamorphic and structural studies. Metamorphic rocks widely occur in the southern Altai Range and have previously been separated into high-T/low-P and medium-P types. Recent studies demonstrated that these two kinds of rocks may have similar protoliths, i.e. early Paleozoic arc-related assemblages, but experienced different metamorphic histories. The development of biotite, garnet, staurolite and kyanite metamorphic zonal sequences in the low- to medium- grade rocks, demonstrate typical medium-pressure metamorphism that has been suggested as a major consequence of the orogenesis. The high-T/low-P metamorphism, represented by the growth of garnet+cordierite+sillimanite+k-feldspar and was accompanied by extensive anatexis, remains its tectonic significance poorly constrained. Field structural investigation in the Chinese Altai reveals that the high-T/low-P metamorphic rocks have major S-L fabrics (defined by the strongly aligned biotite and sillimanite) exactly in the same orientations as those developed in the associated medium-P grade rocks. Geochronological studies constrain the major fabrics in both kinds of rocks developed during mid-Devonian, coeval with the strong magmatism in the region. Micro-structural investigation on both kinds of rocks show similar prograde metamorphic history featured by clockwise P-T path evolution. Phase equilibrium modeling in the MnNCKFMASH system indicates that the development of major fabrics in the medium-P metamorphic rocks mainly recorded the notable increase of

A stable isotope study of serpentinization and metamorphism in the Highland Border Suite, Scotland, UK

International Nuclear Information System (INIS)

Ikin, N.P.; Harmon, R.S.

1983-01-01

D/H and 18 O/ 16 O ratios have been measured for whole-rock samples and mineral separates from the mafic and ultramafic rocks of the Cambro-Ordovician Highland Border Suite. The H- and O-isotopic compositions of these rocks record individual stages in a relatively complex 500 Myr old hydrothermal/ metamorphic history. Lizardite serpentinites record a premetamorphic history and indicate that parent harzburgites, dunites, and pyroxenites were serpentinized through low-temperature interaction with meteoric waters during cooling. The other rocks of the Highland Border Suite record subsequent interaction with metamorphic fluids. Amphibolite facies hornblende schists were produced through thrust-related metamorphism of spilitic pillow lavas. During dehydration, D-enriched fluids were driven off from the spilites thus leaving the hornblende schists to equilibrate with a relatively D-depleted internal fluid reservoir. The expelled D-enriched fluids may have mixed with more typical Dalradian metamorphic waters which then exchanged with the remaining mafic rocks and lizardite serpentinites during greenschist facies regional metamorphism to produce antigorite serpentinites and greenschist metaspilites with similar H- and O-isotopic compositions. Serpentinites which have been only partially metamorphosed show intermediate H-isotopic compositions between that of metamorphic antigorite and non-metamorphic lizardite end members. (author)

K-Ar ages of the low-grade metamorphic rocks in the Altar massif, Northwest Sonora, Mexico

International Nuclear Information System (INIS)

Hayama, Yoshikazu; Shibata, Ken; Takeda, Hideo.

1984-01-01

The K-Ar ages of low-grade regional metamorphism, granodiorite intrusion and its contact metamorphism were studied in the Altar massif of Northwest Sonora, Mexico. The results gave the ages of 55 Ma for metamorphic hornblende and 15 to 17 Ma for mica of metamorphic rocks and granodiorite. About the meaning of these discordant ages and the too young ages of 15 to 17 Ma against the previously presented data, we pointed out the following two possibilities; 1) the contact effect of the Miocene granodiorite on the regional metamorphic rocks of the Laramide phase, 2) both regional metamorphism and granodiorite intrusion took place during the Laramide phase, whereas the young ages, 15 to 17 Ma, show the time of temperature release after the low-angle thrust movement, which is well known in the hinterland of the Sevier orogenic belt in Nevada and Utah. (author)

First evidence of the Ellesmerian metamorphism on Svalbard

Science.gov (United States)

Kośmińska, Karolina; Majka, Jarosław; Manecki, Maciej; Schneider, David A.

2016-04-01

The Ellesmerian fold-and-thrust belt is exposed in the High Arctic from Ellesmere Island in the east, through North Greenland, to Svalbard in the west (e.g. Piepjohn et al., 2015). It developed during Late Devonian - Early Carboniferous, and overprinted older (mainly Caledonian) structures. It is thought that this fold-and-thrust belt was formed due to collision of the Pearya Terrane and Svalbard with the Franklinian Basin of Laurentia. Traditionally, the Ellesmerian fold-and-thrust belt comprises a passive continental margin affected by foreland deformation processes, but the exact larger scale tectonic context of this belt is disputable. It is partly because the Eocene Eurekan deformation superimposed significantly the Ellesmerian structures, thus making the reconstruction of the pre-Eurekan history very difficult. Here we present for the first time evidence for Ellesmerian metamorphism within the crystalline basement of Svalbard. These rocks are exposed in the Pinkie unit on Prins Karls Forland (W-Svalbard), which exhibits tectonic contacts with the overlying sequences. The Pinkie unit is mainly composed of strongly deformed lithologies such as laminated quartzites, siliciclastic rocks and garnet-bearing mica schists. Detrital zircon dating yielded ages as young as Neoproterozoic (0.95-1.05 Ga), thus the Pinkie unit is considered to be Neoproterozoic (Kośmińska et al., 2015a). The M1 assemblages and D1 structures are affected by D2 mylonitization (cf. Faehnrich et al., 2016, this meeting). Petrological characterization and Th-U-total Pb chemical monazite dating have been performed on the Pinkie metapelites. These rocks exhibit an apparent inverted Barrovian metamorphic sequence, within which three metamorphic zones have been distinguished: garnet+staurolite+muscovite+biotite, garnet+staurolite+kyanite+muscovite+biotite, garnet+kyanite+muscovite+biotite. The P-T estimates using the QuiG barometry coupled with thermodynamic modelling revealed that the

Age and kinematics of ductile deformation in the Cerro Durazno area, NW Argentina: Significance for orogenic processes operating at the western margin of Gondwana during Ordovician - Silurian times

Science.gov (United States)

Wegmann, Maja I.; Riller, Ulrich; Hongn, Fernando D.; Glodny, Johannes; Oncken, Onno

2008-07-01

The Cerro Durazno Pluton belongs to a suite of Paleozoic granitoid intrusions in NW-Argentina, that are central for understanding the tectonic setting of the western margin of Gondwana in Ordovician and Silurian times. The pluton and its host rocks were tectonically overprinted by metamorphic mineral shape fabrics formed under middle greenschist-facies metamorphic conditions and associated with the nearby Agua Rosada Shear Zone. Kinematic analysis of the shear zone based on the geometric relationship between individual segments of the shear plane and principal axes of mineral fabric ellipsoids indicates reverse-sense of shear with a minor component of left-lateral displacement. This is compatible with the kinematics of other ductile deformation zones in this area, collectively forming a network, which accomplished orogen-parallel extension in addition to vertical thickening. Using the Rb-Sr isotopic system, an undeformed pegmatite dike of the Cerro Durazno Pluton was dated at 455.8 ± 3.6 Ma and mineral fabrics of the Agua Rosada Shear Zone formed at middle greenschist-facies metamorphism gave deformation ages of 437.0 ± 3.8 Ma and ⩽428.4 ± 4.5 Ma. Thus, tectonic overprint at low metamorphic grade occurred about 20-30 Ma after terminal magmatism in the Cerro Durazno area. Our data from the Cerro Durazno area and regional considerations suggest that the western margin of Gondwana was characterized by orogen-parallel extension in addition to crustal thickening as well as episodes of magmatism and ductile deformation that varied greatly in time and space.

Metamorphism and partial melting of ordinary chondrites: Calculated phase equilibria

Science.gov (United States)

Johnson, T. E.; Benedix, G. K.; Bland, P. A.

2016-01-01

Constraining the metamorphic pressures (P) and temperatures (T) recorded by meteorites is key to understanding the size and thermal history of their asteroid parent bodies. New thermodynamic models calibrated to very low P for minerals and melt in terrestrial mantle peridotite permit quantitative investigation of high-T metamorphism in ordinary chondrites using phase equilibria modelling. Isochemical P-T phase diagrams based on the average composition of H, L and LL chondrite falls and contoured for the composition and abundance of olivine, ortho- and clinopyroxene, plagioclase and chromite provide a good match with values measured in so-called equilibrated (petrologic type 4-6) samples. Some compositional variables, in particular Al in orthopyroxene and Na in clinopyroxene, exhibit a strong pressure dependence when considered over a range of several kilobars, providing a means of recognising meteorites derived from the cores of asteroids with radii of several hundred kilometres, if such bodies existed at that time. At the low pressures (recorders of peak conditions. The intersection of isopleths of these variables may allow pressures to be quantified, even at low P, permitting constraints on the minimum size of parent asteroid bodies. The phase diagrams predict the onset of partial melting at 1050-1100 °C by incongruent reactions consuming plagioclase, clinopyroxene and orthopyroxene, whose compositions change abruptly as melting proceeds. These predictions match natural observations well and support the view that type 7 chondrites represent a suprasolidus continuation of the established petrologic types at the extremes of thermal metamorphism. The results suggest phase equilibria modelling has potential as a powerful quantitative tool in investigating, for example, progressive oxidation during metamorphism, the degree of melting and melt loss or accumulation required to produce the spectrum of differentiated meteorites, and whether the onion shell or rubble pile

Geochemistry and paleotectonomagmatic setting of metabasites protolith from Asalem metamorphic complex (northwest Rasht

Directory of Open Access Journals (Sweden)

Mohsen Nasrabady

2016-12-01

Full Text Available Asalem metamorphic complex consists mostly of metabasite, metapelite and serpentinite. Metabasites display metamorphic features of greenschist and blueschist facies. Greenschist facies rocks that found as both foliated and massive types contain mineralogical assemblage of actinolite, chlorite, albite and epidote. Blueschists contain mineralogical assemblage of sodic amphibole, epidote and phengite. Whole rock analyses of the metabasites indicate basaltic to andesitic composition with mainly calcalkaline nature of their protolith. According to the discrimination diagrams of tectonomagmatic setting, the protolith of investigated metabasites has been islands arc and somewhat mid ocean ridge. The patterns of rare earth elements and spider diagrams of the Asalem metabasites resemble to the basic and intermediate magmatism of islands arc or suprasubduction setting as well. Greenschists and blueschists facies rocks of the Asalem metamorphic complex have been probably equivalent to islands arc or young and hot oceanic crust of suprasubduction zone setting. This portion of oceanic basin unlike the subducted even and thick oceanic lithosphere of Paleotethys during accretion in the shallower levels of accretionary prisms, have underwent metamorphic conditions of blueschist and greenschist facies and finally gave rise to the formation of the metabasites of the Asalem metamorphic complex.

Thermal effects of metamorphic reactions in a three-component slab

DEFF Research Database (Denmark)

Chemia, Zurab; Dolejš, David; Steinle-Neumann, Gerd

2010-01-01

Thermal evolution of a subducting crust is of primary importance for understanding physical properties, phase transformations, fluid migration and melting regimes at convergent plate boundaries. Various factors influencing the thermal structure of a subduction zone have been considered previously......), and moderately serpentinized harzburgite (SHB). These layers are examined over the range of pressure-temperature conditions of interest by computing metamorphic phase diagrams and retrieving whole-rock thermodynamic properties. Our results suggest that metamorphic reactions consume a significant amount of slab...

Pre-Alpine contrasting tectono-metamorphic evolutions within the Southern Steep Belt, Central Alps

Science.gov (United States)

Roda, Manuel; Zucali, Michele; Li, Zheng-Xiang; Spalla, Maria Iole; Yao, Weihua

2018-06-01

In the Southern Steep Belt, Italian Central Alps, relicts of the pre-Alpine continental crust are preserved. Between Valtellina and Val Camonica, a poly-metamorphic rock association occurs, which belongs to the Austroalpine units and includes two classically subdivided units: the Languard-Campo nappe (LCN) and the Tonale Series (TS). The outcropping rocks are low to medium grade muscovite, biotite and minor staurolite-bearing gneisses and micaschists, which include interlayered garnet- and biotite-bearing amphibolites, marbles, quartzites and pegmatites, as well as sillimanite-bearing gneisses and micaschists. Permian intrusives (granitoids, diorites and minor gabbros) emplaced in the metamorphic rocks. We performed a detailed structural, petrological and geochronological analysis focusing on the two main lithotypes, namely, staurolite-bearing micaschists and sillimanite-bearing paragneisses, to reconstruct the Variscan and Permian-Triassic history of this crustal section. The reconstruction of the tectono-metamorphic evolution allows for the distinction between two different tectono-metamorphic units during the early pre-Alpine evolution (D1) and predates the Permian intrusives, which comprise rocks from both TS and LCN. In the staurolite-bearing micaschists, D1 developed under amphibolite facies conditions (P = 0.7-1.1 GPa, T = 580-660 °C), while in the sillimanite-bearing paragneisses formed under granulite facies conditions (P = 0.6-1.0 GPa, T> 780 °C). The two tectono-metamorphic units coupled together during the second pre-Alpine stage (D2) under granulite-amphibolite facies conditions at a lower pressure (P = 0.4-0.6 GPa, T = 620-750 °C) forming a single tectono-metamorphic unit (Languard-Tonale Tectono-Metamorphic Unit), which comprised the previously distinguished LCN and TS. Geochronological analyses on zircon rims indicate ages ranging between 250 and 275 Ma for D2, contemporaneous with the emplacement of Permian intrusives. This event developed under

Cathodoluminescence (CL Characteristics of Quartz from Different Metamorphic Rocks within the Kaoko Belt (Namibia

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Jonathan Sittner

2018-05-01

Full Text Available Quartz of metamorphic rocks from the Kaoko belt (Namibia representing metamorphic zones from greenshist to granulite facies were investigated by cathodoluminescence (CL microscopy and spectroscopy to characterize their CL properties. The samples cover P-T conditions from the garnet zone (500 ± 30 °C, 9 ± 1 kbar up to the garnet-cordierite-sillimanite-K-feldspar zone (750 ± 30 °C, 4.0–5.5 kbar. Quartz from 10 different localities and metamorphic environments exclusively exhibits blue CL. The observed CL colors and spectra seem to be more or less independent of the metamorphic grade of the host rocks, but are determined by the regional geological conditions. Quartz from different localities of the garnet-cordierite-sillimanite-K-feldspar zone shows a dominant 450 nm emission band similar to quartz from igneous rocks, which might be related to recrystallization processes. In contrast, quartz from different metamorphic zones in the western part of the central Kaoko zone (garnet, staurolite, kyanite, and kyanite-sillimanite-muscovite zone is characterized by a heterogeneous blue-green CL and a dominant 500 nm emission band that strongly decreases in intensity under electron irradiation. Such CL characteristics are typical for quartz of pegmatitic and/or hydrothermal origin and indicate the participation of fluids during neoformation of quartz during metamorphism.

Petrographic and Geochemical Study of Low Grade Metamorphic ...

African Journals Online (AJOL)

Key words: Low grade metamorphic rocks, Base metal mineralization, Petrography,. Hydrogeochemistry, Negash ... Use of mineral deposit genetic models has become an important ..... The clasts show elongation due to deformation, parallel.

Evolutionary genetics of metamorphic failure using wild-caught vs. laboratory axolotls (Ambystoma mexicanum).

Science.gov (United States)

Voss, S R; Shaffer, H B

2000-09-01

In many organisms metamorphosis allows for an ecologically important habitat-shift from water to land. However, in some salamanders an adaptive life cycle mode has evolved that is characterized by metamorphic failure (paedomorphosis); these species remain in the aquatic habitat throughout the life cycle. Perhaps the most famous example of metamorphic failure is the Mexican axolotl (Ambystoma mexicanum), which has become a focal species for developmental biology since it was introduced into laboratory culture in the 1800s. Our previous genetic linkage mapping analysis, using an interspecific crossing design, demonstrated that a major gene effect underlies the expression of metamorphic failure in laboratory stocks of the Mexican axolotl. Here, we repeated this experiment using A. mexicanum that were sampled directly from their natural habitat at Lake Xochimilco, Mexico. We found no significant association between the major gene and metamorphic failure when wild-caught axolotls were used in the experimental design, although there is evidence of a smaller genetic effect. Thus, there appears to be genetic variation among Mexican axolotls (and possibly A. tigrinum tigrinum) at loci that contribute to metamorphic failure. This result suggests a role for more than one mutation and possibly artificial selection in the evolution of the major gene effect in the laboratory Mexican axolotl.

Argentina

International Nuclear Information System (INIS)

Tanis, S.; Ramberg, B.

1990-01-01

Argentina has embarked on an ambitious domestic nuclear research and energy program. The venture promises to provide the nation with the infrastructure to play an important role in the nuclear export market in the years ahead. Buenos Aires built its program on a foundation of international support and assistance that overlay an emerging sophisticated industrial and scientific establishment. The foreign contribution sensitized Argentina to opportunities in the global market. This paper reports that Argentina operates two heavy-water/natural uranium reactors, Atucha I and Embalse. Producing, respectively, 320 MW(e) and 600 MW(e), they supply roughly 10 percent of the country's electricity. With a capacity factor of 84 percent, Atucha I is among the best operated plants in the world. Plans call for a third, 745 MW(e) power plant, Atucha II, to go on line in the early 1990s. During this period, construction also may begin on three 300 MW(e) plants, although the country's foreign indebtedness plus cost overruns in earlier construction will place a heavy burden on these plans

Structural evolution of the Semail Ophiolite metamorphic sole, Wadi Hawasina and Northern Jebel Nakhl Culmination, Oman

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Hurtado, C.; Bailey, C.; Visokay, L.; Scharf, A.

2017-12-01

The Semail ophiolite is the world's largest and best-exposed ophiolite sequence, however the processes associated with both oceanic detachment and later emplacement onto the Arabian continental margin remain enigmatic. This study examines the upper mantle section of the ophiolite, its associated metamorphic sole, and the autochthonous strata beneath the ophiolite at two locations in northern Oman. Our purpose is to understand the structural history of ophiolite emplacement and evaluate the deformation kinematics of faulted and sheared rocks in the metamorphic sole. At Wadi Hawasina, the base of the ophiolite is defined by a 5- to 15-m thick zone of penetratively-serpentinized mylonitic peridotite. Kinematic indicators record top-to-the SW (reverse) sense-of-shear with a triclinic deformation asymmetry. An inverted metamorphic grade is preserved in the 300- to 500-m thick metamorphic sole that is thrust over deep-water sedimentary rocks of the Hawasina Group. The study site near Buwah, in the northern Jebel Nakhl culmination, contains a N-to-S progression of mantle peridotite, metamorphic sole, and underlying Jurassic carbonates. Liswanite crops out in NW-SE trending linear ridges in the peridotite. The metamorphic sole includes well-foliated quartzite, metachert, and amphibolite. Kinematic evidence indicates that the liswanite and a serpentinized mélange experienced top to-the north (normal) sense-of-shear. Two generations of E-W striking, N-dipping normal faults separate the autochthonous sequence from the metamorphic sole, and also cut out significant sections of the metamorphic sole. Fabric analysis reveals that the metamorphic sole experienced flattening strain (K<0.2) that accumulated during pure shear-dominated general shear (Wk<0.4). Normal faulting and extension at the Buwah site indicates that post-ophiolite deformation is significant in the Jebel Akhdar and Jebel Nakhl culminations.

Effect of food on metamorphic competence in the model system Crepidula fornicata.

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Padilla, Dianna K; McCann, Michael J; Glenn, Mica McCarty; Hooks, Alexandra P; Shumway, Sandra E

2014-12-01

Food quality and quantity, as well as temperature, are all factors that are expected to affect rates of development, and are likely to be affected by expected climatic change. We tested the effect of a mixed diet versus a single-food diet on metamorphic competence in the emerging model species Crepidula fornicata. We then compared our results with other published studies on this species that examined time to metamorphic competence across a range of food concentrations and rearing temperatures. Ours was the only study to test the effects of single food versus a mixed diet on metamorphic competence for this species. Diet composition did not affect metamorphic competence or survivorship. Comparing results across studies, we found that the shortest time to metamorphic competence was typically found when the food availability per larva was the greatest, independent of rearing temperature. Unfortunately, some published studies did not include important metadata needed for comparison with other studies; these data included larval rearing density, food density, frequency of feeding, and rearing temperature. Mortality rates were not always reported and when reported were often measured in different ways, preventing comparison. Such metadata are essential for comparisons among studies as well as among taxa, and for the determination of generalizable patterns and evolutionary trends. Increased reporting of all such metadata is essential if we are to use scientific studies performed to their fullest potential. © 2014 Marine Biological Laboratory.

Fluid heterogeneity during granulite facies metamorphism in the Adirondacks: stable isotope evidence

Science.gov (United States)

Valley, J.W.; O'Neil, J.R.

1984-01-01

The preservation of premetamorphic, whole-rock oxygen isotope ratios in Adirondack metasediments shows that neither these rocks nor adjacent anorthosites and gneisses have been penetrated by large amounts of externally derived, hot CO2-H2O fluids during granulite facies metamorphism. This conclusion is supported by calculations of the effect of fluid volatilization and exchange and is also independently supported by petrologic and phase equilibria considerations. The data suggest that these rocks were not an open system during metamorphism; that fluid/rock ratios were in many instances between 0.0 and 0.1; that externally derived fluids, as well as fluids derived by metamorphic volatilization, rose along localized channels and were not pervasive; and thus that no single generalization can be applied to metamorphic fluid conditions in the Adirondacks. Analyses of 3 to 4 coexisting minerals from Adirondack marbles show that isotopic equilibrium was attained at the peak of granulite and upper amphibolite facies metamorphism. Thus the isotopic compositions of metamorphic fluids can be inferred from analyses of carbonates and fluid budgets can be constructed. Carbonates from the granulite facies are on average, isotopically similar to those from lower grade or unmetamorphosed limestones of the same age showing that no large isotopic shifts accompanied high grade metamorphism. Equilibrium calculations indicate that small decreases in ??18O, averaging 1 permil, result from volatilization reactions for Adirondack rock compositions. Additional small differences between amphibolite and granulite facies marbles are due to systematic lithologie differences. The range of Adirondack carbonate ??18O values (12.3 to 27.2) can be explained by the highly variable isotopic compositions of unmetamorphosed limestones in conjunction with minor 18O and 13C depletions caused by metamorphic volatilization suggesting that many (and possibly most) marbles have closely preserved their

Tectono-metamorphic evolution of the Jomolhari massif: Variations in timing of syn-collisional metamorphism across western Bhutan

Science.gov (United States)

Regis, Daniele; Warren, Clare J.; Young, David; Roberts, Nick M. W.

2014-03-01

Our current understanding of the rates and timescales of mountain-building processes is largely based on information recorded in U-bearing accessory minerals such as monazite, which is found in low abundance but which hosts the majority of the trace element budget. Monazite petrochronology was used to investigate the timing of crustal melting in migmatitic metasedimentary rocks from the Jomolhari massif (NW Bhutan). The samples were metamorphosed at upper amphibolite to granulite facies conditions (~ 0.85 GPa, ~ 800 °C), after an earlier High-Pressure stage (P > 1.4 GPa), and underwent partial melting through dehydration melting reactions involving muscovite and biotite. In order to link the timing of monazite growth/dissolution to the pressure-temperature (P-T) evolution of the samples, we identified 'chemical fingerprints' in major and accessory phases that were used to back-trace specific metamorphic reactions. Variations in Eu anomaly and Ti in garnet were linked to the growth and dissolution of major phases (e.g. growth of K-feldspar and dehydration melting of muscovite/biotite). Differences in M/HREE and Y from garnet core to rim were instead related to apatite breakdown and monazite-forming reactions. Chemically zoned monazite crystals reacted multiple times during the metamorphic evolution suggesting that the Jomolhari massif experienced a prolonged high-temperature metamorphic evolution from 36 Ma to 18 Ma, significantly different from the P-T-time path recorded in other portions of the Greater Himalayan Sequence (GHS) in Bhutan. Our data demonstrate unequivocally that the GHS in Bhutan consists of units that experienced independent high-grade histories and that were juxtaposed across different tectonic structures during exhumation. The GHS may have been exhumed in response to (pulsed) mid-crustal flow but cannot be considered a coherent block.

Long-term landscape evolution of the South Atlantic "passive" continental margin in Eastern Argentina using apatite fission-track thermochronology

Science.gov (United States)

Pfister, Sabrina; Kollenz, Sebastian; Glasmacher, Ulrich A.

2015-04-01

To understand the evolution of the "passive" continental margin in Argentina low temperature thermochronology is an appropriate method, which might lead to new insights in this area. The Tandilia System, also called Sierras Septentrionales, is located south of the Río de la Plato Craton in eastern Argentina in the state of Buenos Aires. North of the hills the Salado basin is located whereas the Claromecó basin is situated south of the mountain range. In contrary to most basins along the South American "passive" continental margin, the Tandilia-System and the neighbouring basins trend perpendicular to the coast line. The topography is fairly flat with altitudes up to 350 m. The igneous-metamorphic basement is pre-Proterozoic in age and build up of mainly granitic-tonalitic gneisses, migmatites, amphibolites, some ultramafic rocks and granitoid plutons. It is overlain by a series of Neoproterozoic to early Paleozoic sedimentary rocks (Cingolani 2011), like siliciclastic rocks, dolostones, shales and limestones (Demoulin 2005). The aim of the study is to quantify the long-term landscape evolution of the "passive" continental margin in eastern Argentina in terms of thermal, exhumation and tectonic evolution. For that purpose, samples were taken from the basement of the Sierra Septentrionales and analyzed with the apatite fission-track method. Further 2-D thermokinematic modeling was conducted with the computer code HeFTy (Ketcham 2005; Ketcham 2007; Ketcham et al. 2009). Because there are different hypotheses in literature regarding the geological evolution of this area two different models were generated, one after Demoulin et al. (2005) and another after Zalba et al.(2007). All samples were taken from the Neoproterozoic igneous-metamorphic basement. Apatite fission-track ages range from 101.6 (9.4) to 228.9 (22.3) Ma, and, therefore, are younger than their formation age, indicating all samples have been thermally reset. Six samples accomplished enough confined

Anisotropy effect on strengths of metamorphic rocks

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Ahmet Özbek

2018-02-01

Full Text Available This paper aims to study the effect of anisotropy on strengths of several metamorphic rocks of southern (Çine submassif of Menderes metamorphic massif in southwest Turkey. Four different metamorphic rocks including foliated phyllite, schist, gneiss and marble (calcschist were selected and examined. Discontinuity surveys were made along lines for each rock and evaluated with DIPS program. L-type Schmidt hammer was applied in the directions parallel and perpendicular to foliation during the field study. Several hand samples and rock blocks were collected during the field study for measurements of dry and saturated densities, dry and saturated unit weights and porosity, and for petrographic analysis and strength determination in laboratory. L- and N-type Schmidt hammers were applied in the directions perpendicular (anisotropy angle of 0° and parallel (anisotropy angle of 90° to the foliation on selected blocks of phyllite, schist, gneiss and marble (calcschist. The phyllite and schist have higher porosity and lower density values than the other rocks. However, coarse crystalline gneiss and marble (calcschist have higher rebound values and strengths, and they are classified as strong–very strong rocks. Generally, the rebound values in the direction perpendicular to the foliation are slightly higher than that in the direction parallel to foliation. Rebound values of N-type Schmidt hammer are higher than the L-type values except for phyllite. Sometimes, the rebound values of laboratory and field applications gave different results. This may result from variable local conditions such as minerals differentiation, discontinuities, water content, weathering degree and thickness of foliated structure.

Metamorphic Testing for Cybersecurity.

Science.gov (United States)

Chen, Tsong Yueh; Kuo, Fei-Ching; Ma, Wenjuan; Susilo, Willy; Towey, Dave; Voas, Jeffrey; Zhou, Zhi Quan

2016-06-01

Testing is a major approach for the detection of software defects, including vulnerabilities in security features. This article introduces metamorphic testing (MT), a relatively new testing method, and discusses how the new perspective of MT can help to conduct negative testing as well as to alleviate the oracle problem in the testing of security-related functionality and behavior. As demonstrated by the effectiveness of MT in detecting previously unknown bugs in real-world critical applications such as compilers and code obfuscators, we conclude that software testing of security-related features should be conducted from diverse perspectives in order to achieve greater cybersecurity.

Metamorphic rocks in the deep boreholes near Maribor

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Mirka Trajanova

2002-12-01

Full Text Available Six research-captive boreholes for thermal water passed through a pile of metamorphic rocks near Maribor (Eastern Slovenia that is on average about 1000 m thick. The succession of metamorphic rocks is characteristic for the Pohorje Mt. and eastern Kobansko region. In the area of the boreholes two tectonic zones are more pronounced: the upper one, at a depth of about 510 to 550 m at the contact of the Štelenska Gora and Phyllite formations and the deeper one at a depth of about 460 to 590 m, indicating the reverse fault junction of the Phyllite and Kobansko formations. They belong to the second andthe third thrust unit of the accretionary wedge formed at the collision of the European and African plates. Four Alpine nappe units are proven in the Slovenian part of the Eastern Alps.

Early planetary metamorphism in chondritic meteorites

International Nuclear Information System (INIS)

Hanan, B.B.; Tilton, G.R.

1985-01-01

Lead isotope relations were studied in whole rock and separated phases of Mezoe-Madaras (L3) and Sharps (H3) chondrites in order to study the record of early events in the solar system and to seek further information on the isotopic composition of primordial lead. The internal 207 Pb/ 206 Pb ages are 4.480+-0.011 AE (1 AE=10 9 years) for Mezoe-Madaras and 4.472+-0.005 AE for Sharps. The ages are not significantly changed when Canyon Diablo troilite lead is included in the data sets, suggesting that the initial Pb isotopic composition in both meteorites was the same as that in the troilite. U-Pb data from both meteorites plot along chords in concordia diagrams that indicate recent disturbances in U/Pb ratios. The chords are poorly defined owing to the relatively non-radiogenic character of the lead isotopes. Rb-Sr measurements on Sharps likewise fail to yield an isochron, in agreement with the U-Pb data. Data from the literature indicate a similar disturbance in the Rb-Sr system for Mezoe-Madaras. The 4.48 AE ages could be caused by pre-analysis contamination with terrestrial lead, however statistical comparison of isotope correlations between the acid-washes of analyzed samples and the residual washed samples suggests that the ages are real and not due to terrestrial contamination. The 4.48 AE age, which is distinctly younger than the well-established ages of 4.54-4.56 AE for the Allende chondrite and Angra dos Reis achondrite, appears to date an early metamorphic event rather than the formation of the chondrites. Rb-Sr, Sm-Nd and K-Ar ages in support of the 4.48 AE metamorphic event are reviewed. Such a metamorphic age is not necessarily in conflict with 129 I/ 129 Xe data which indicate that the parent material of most chondrites, including those of type 3, cooled through temperatures sufficient to retain radiogenic Xe within a time interval of ca. 0.02 AE. (orig.)

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

Science.gov (United States)

Slotznick, Sarah P.; Eiler, John M.; Fischer, Woodward W.

2018-03-01

As the most abundant transition metal in the Earth's crust, iron is a key player in the planetary redox budget. Observations of iron minerals in the sedimentary record have been used to describe atmospheric and aqueous redox environments over the evolution of our planet; the most common method applied is iron speciation, a geochemical sequential extraction method in which proportions of different iron minerals are compared to calibrations from modern sediments to determine water-column redox state. Less is known about how this proxy records information through post-depositional processes, including diagenesis and metamorphism. To get insight into this, we examined how the iron mineral groups/pools (silicates, oxides, sulfides, etc.) and paleoredox proxy interpretations can be affected by known metamorphic processes. Well-known metamorphic reactions occurring in sub-chlorite to kyanite rocks are able to move iron between different iron pools along a range of proxy vectors, potentially affecting paleoredox results. To quantify the effect strength of these reactions, we examined mineralogical and geochemical data from two classic localities where Silurian-Devonian shales, sandstones, and carbonates deposited in a marine sedimentary basin with oxygenated seawater (based on global and local biological constraints) have been regionally metamorphosed from lower-greenschist facies to granulite facies: Waits River and Gile Mountain Formations, Vermont, USA and the Waterville and Sangerville-Vassalboro Formations, Maine, USA. Plotting iron speciation ratios determined for samples from these localities revealed apparent paleoredox conditions of the depositional water column spanning the entire range from oxic to ferruginous (anoxic) to euxinic (anoxic and sulfidic). Pyrrhotite formation in samples highlighted problems within the proxy as iron pool assignment required assumptions about metamorphic reactions and pyrrhotite's identification depended on the extraction techniques

Metamorphic complexes in accretionary orogens: Insights from the Beishan collage, southern Central Asian Orogenic Belt

Science.gov (United States)

Song, Dongfang; Xiao, Wenjiao; Windley, Brian F.; Han, Chunming; Yang, Lei

2016-10-01

The sources of ancient zircons and the tectonic attributions and origins of metamorphic complexes in Phanerozoic accretionary orogens have long been difficult issues. Situated between the Tianshan and Inner Mongolia orogens, the Beishan orogenic collage (BOC) plays a pivotal role in understanding the accretionary processes of the southern Central Asian Orogenic Belt (CAOB), particularly the extensive metamorphic and high-strained complexes on the southern margin. Despite their importance in understanding the basic architecture of the southern CAOB, little consensus has been reached on their ages and origins. Our new structural, LA-ICP-MS zircon U-Pb and Hf isotopic data from the Baidunzi, Shibandun, Qiaowan and Wutongjing metamorphic complexes resolve current controversial relations. The metamorphic complexes have varied lithologies and structures. Detrital zircons from five para-metamorphic rocks yield predominantly Phanerozoic ages with single major peaks at ca. 276 Ma, 286 Ma, 427 Ma, 428 Ma and 461 Ma. Two orthogneisses have weighted mean ages of 294 ± 2 Ma and 304 ± 2 Ma with no Precambrian inherited zircons. Most Phanerozoic zircons show positive εHf(t) values indicating significant crustal growth in the Ordovician, Silurian and Permian. The imbricated fold-thrust deformation style combined with diagnostic zircon U-Pb-Hf isotopic data demonstrate that the metamorphic rocks developed in a subduction-accretion setting on an arc or active continental margin. This setting and conclusion are supported by the nearby occurrence of Ordovician-Silurian adakites, Nb-rich basalts, Carboniferous-Permian ophiolitic mélanges, and trench-type turbidites. Current data do not support the presence of a widespread Precambrian basement in the evolution of the BOC; the accretionary processes may have continued to the early Permian in this part of the CAOB. These relationships have meaningful implications for the interpretation of the tectonic attributions and origins of other

High Radiation Resistance Inverted Metamorphic Solar Cell, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The innovation in this SBIR Phase II project is the development of a unique triple junction inverted metamorphic technology (IMM), which will enable the...

Cordilleran metamorphic core complexes and their uranium favorability. Final report

International Nuclear Information System (INIS)

Coney, P.J.; Reynolds, S.J.

1980-11-01

The objective of this report is to provide a descriptive body of knowledge on Cordilleran metamorphic core complexes including their lithologic and structural characteristics, their distribution within the Cordillera, and their evolutionary history and tectonic setting. The occurrence of uranium in the context of possibility for uranium concentration is also examined. Chapter 1 is an overview of Cordilleran metamorphic core complexes which describes their physical characteristics, tectonic setting and geologic history. This overview is accompanied by a tectonic map. Chapter 2 is a discussion of the mantled gneiss dome concept. The purpose of including this work is to provide a basic history of this concept and to describe the characteristics and distribution of gneiss domes throughout the world to enable one to compare and contrast them with the metamorphic core complexes as discussed in this report. Some gneiss domes are known producers of uranium (as are also some core complexes). Chapter 3 is an examination of the effects of the core complex process on adjacent sedimentary and volcanic cover terranes. Also included is a discussion of the kinematic significance of these cover terranes as they are related to process within the cores of the complexes. Some of the cover terranes have uranium prospects in them. Chapter 4 is a detailed discussion of uranium in Cordilleran metamorphic core complexes and includes the conceptual basis for the various types of occurrences and the processes that might favor concentration of uranium. The report is supported by a 5-part Appendix. The majority of the core complexes discussed in this report either do not appear or are not recognizable on existing published geologic maps

Metamorphic Testing for Cybersecurity

Science.gov (United States)

Chen, Tsong Yueh; Kuo, Fei-Ching; Ma, Wenjuan; Susilo, Willy; Towey, Dave; Voas, Jeffrey

2016-01-01

Testing is a major approach for the detection of software defects, including vulnerabilities in security features. This article introduces metamorphic testing (MT), a relatively new testing method, and discusses how the new perspective of MT can help to conduct negative testing as well as to alleviate the oracle problem in the testing of security-related functionality and behavior. As demonstrated by the effectiveness of MT in detecting previously unknown bugs in real-world critical applications such as compilers and code obfuscators, we conclude that software testing of security-related features should be conducted from diverse perspectives in order to achieve greater cybersecurity. PMID:27559196

Monazite behaviours during high-temperature metamorphism: a case study from Dinggye region, Tibetan Himalaya

Science.gov (United States)

Wang, Jia-Min; Wu, Fu-Yuan; Rubatto, Daniela; Liu, Shi-Ran; Zhang, Jin-Jiang

2017-04-01

Monazite is a key accessory mineral for metamorphic geochronology, but its growth mechanisms during melt-bearing high-temperature metamorphism is not well understood. Therefore, the petrology, pressure-temperature and timing of metamorphism have been investigated in pelitic and psammitic granulites from the Greater Himalayan Crystalline Complex (GHC) in Dinggye, southern Tibet. These rocks underwent an isothermal decompression process from pressure conditions of >10 kbar to armour effect of matrix crystals (biotite and quartz). Most monazite grains formed at the M3-stage (21-19 Ma) through either dissolution-reprecipitation or recrystallization that was related to biotite dehydration melting reaction. These monazite grains record HREE and Y signatures in local equilibrium with different reactions involving either garnet breakdown or peritectic garnet growth. Another peak of monazite growth occurs during melt crystallization ( 15 Ma), and these monazites are unzoned and have homogeneous compositions. Our results documented the widespread recrystallization to account for monazite growth during high-temperature metamorphism and related melting reactions that trigger monazite recrystallization. In a regional sense, our P-T-t data along with published data indicate that the pre-M1 eclogite-facies metamorphism occurred at 39-30 Ma in the Dinggye Himalaya. Our results are in favour of a steady exhumation of the GHC rocks since Oligocene that was contributed by partial melting. Key words: U-Th-Pb geochronology, Monazite, Recrystallization, Pelitic granulite, Himalaya

On the K-Ar ages of the rocks of two kinds existed in the Kamuikotan metamorphic rocks located in the Horokanai district, Hokkaido

International Nuclear Information System (INIS)

Imaizumi, Masayuki; Ueda, Yoshio.

1981-01-01

In the Fransiscan metamorphic rocks known as the typical high-pressure type metamorphic belts, existence of the blocks of high grade metamorphic rocks of older age in the widely distributed low grade ones of younger age is commonly noticed. This feature has been explained as a phenomenon that the blocks had been tectonically mixed with the surroundings - so-called tectonic blocks - based on the absolute age determination of the component minerals. The Kamuikotan tectonic belt is a melange zone in which occur various kinds of metamorphic rocks of high-pressure and low-pressure types. The high-pressure Kamuikotan metamorphic rocks can be classified into two kinds based upon the modes of occurrence and mineral paragenesis. One is the low grade metamorphic rocks of greenschist and glaucophane schist and the other, the high grade metamorphic rocks of epidote glaucophane schist and epidote amphibolite. The high grade metamorphic rocks always occur as isolated blocks in the low grade metamorphics and associated serpentinite. The report discusses the age of muscovites separated from the two types of high-pressure Kamuikotan metamorphic rocks in the Horokanai district, central Hokkaido. The muscovites separated from the low grade metamorphics of the district give the age of 72 - 116 m.y., while those separated from the high grade metamorphics give the age of 132 - 145 m.y. These ages seem to agree with the idea that the blocks of high grade metamorphics (epidote glaucophane schist and epidote amphibolite) would be the ''tectonic blocks'' - namely the fragments tectonically mixed into the low grade metamorphics of younger age. (author)

Characterization of agua de Ramon marbles, Cordoba Province, Argentina

International Nuclear Information System (INIS)

Tourn, S.; Castro, L. . E mail: selvia@fcen.uba.ar, lilianacastro@fibertel.com.ar

2004-01-01

Agua de Ramon district is located in the NW of Cordoba, Argentina, between 3 49' and 30 0 52' S and 65 0 21' and 65 0 24' W, in the Eastern Pampean Range setting. It was a very important tungsten district until the end of 1950'decade when tungsten mining became of no economic interest. The objective is to report for the first time the petrological, mineralogical and geochemical characteristics of several marble lenses located in the sourthern of the area. Marble outcrops are lenticular ranging from 1 m to 80 m in length and 0.50 m to 20 m width. They appear massive, fine-grained and in light colors (white, pale green, very light brown and pale gray). These last varieties show a distinct banded structure due to little differences in color. These marbles are mainly composed of magnesian calcite accompanied by minor amounts of dolomite, forsterite, humite group minerals, tremolite, talc, serpentine and clinochlore, and scheelite, sphene, apatite and opaque minerals like hematite, magnetite, illmenite, pirrothite and pyrite as accessory minerals. Major chemical analyses indicate a relatively high SiO2 and MgO content, and minor CaO, in comparison with marbles of this type. Mineral paragenesis was useful to evaluate metamorphism conditions in this area [es

Metamorphic Evolution of Garnet-bearing Epidote-Barroisite Schist from the Meratus Complex in South Kalimantan, Indonesia

Directory of Open Access Journals (Sweden)

Nugroho Imam Setiawan

2015-09-01

Full Text Available DOI:10.17014/ijog.2.3.139-156This paper presents metamorphic evolution of metamorphic rocks from the Meratus Complex in South Kalimantan, Indonesia. Eight varieties of metamorphic rocks samples from this location, which are garnet-bearing epidote-barroisite schist, epidote-barroisite schist, glaucophane-quartz schist, garnet-muscovite schist, actinolite-talc schist, epidote schist, muscovite schist, and serpentinite, were investigated in detail its petrological and mineralogical characteristics by using polarization microscope and electron probe micro analyzer (EPMA. Furthermore, the pressure-temperature path of garnet-bearing epidote-barroisite schist was estimated by using mineral parageneses, reaction textures, and mineral chemistries to assess the metamorphic history. The primary stage of this rock might be represented by the assemblage of glaucophane + epidote + titanite ± paragonite. The assemblage yields 1.7 - 1.0 GPa in assumed temperature of 300 - 550 °C, which is interpreted as maximum pressure limit of prograde stage. The peak P-T condition estimated on the basis of the equilibrium of garnet rim, barroisite, phengite, epidote, and quartz, yields 547 - 690 °C and 1.1 - 1.5 GPa on the albite epidote amphibolite-facies that correspond to the depth of 38 - 50 km. The retrograde stage was presented by changing mineral compositions of amphiboles from the Si-rich barroisite to the actinolite, which lies near 0.5 GPa at 350 °C. It could be concluded that metamorphic rocks from the Meratus Complex experienced low-temperature and high-pressure conditions (blueschist-facies prior to the peak metamorphism of the epidote amphibolite-facies. The subduction environments in Meratus Complex during Cretaceous should be responsible for this metamorphic condition.

Petrographical and geochemical characterization and deformation conditions of the San Cristobal pluton, Sierra de Velasco, La Rioja, Argentina; Caracterizacion petrografica y geoquimica y condiciones de deformacion del pluton San Cristobal, Sierra de Velasco, La Rioja, Argentina

Energy Technology Data Exchange (ETDEWEB)

Bellos, L.I.; Toselli, A.J.; Rossi, J.N.; Grosse, P.; Rosa, J.D. de la; Castro, A.

2010-07-01

The San Cristobal pluton is a 35 km2 granitic body that outcrops at the southestern tip of the Sierra de Velasco, located west of La Rioja city, Argentina. It is formed by monzogranites and syenogranites, together with scarce granodiorites, with medium to fine-grained, equigranular to slightly porphyritic textures. Their mineral assemblage consists of quartz + microcline + plagioclase + biotite {+-} muscovite + zircon + apatite + magnetite. The granite contains dioritic to tonalitic mafic enclaves. The central and eastern parts of the granite have been deformed by the NNW-SSE trending South Mylonitic shear zone formed by mylonitic rocks. The metamorphic host-rock is represented by scarce greenschist facies xenoliths and hornfels with the high T/P assemblage K-feldspar - cordierite - biotite {+-} sillimanite. The granites are calc-alkaline, weak- to moderately peraluminous, and formed as part of a continental magmatic arc developed along the active margin of western Gondwana during the Early Paleozoic. The depth of emplacement of the San Cristobal pluton is estimated at {approx}12 km. (Author).

Geology and genesis of uranium deposits in sedimentary and metamorphic formation

International Nuclear Information System (INIS)

Danchev, V.I.; Belevtsev, Ya.N.

1980-01-01

Main genetic types of uranium deposits in sedimentary cover are described. Their genetic classification is based on the principle of conjugation of ore-forming process with the stages of lithogenesis of ore-enclosing rocks. Examples of poligeneity of uranium mineralization are presented. Texture-structural peculiarities of ores and types of ore-controlling zonality are considered as criteria of definite deposits belonging to various genetic classes. The analysis is given of main regularities of location of exogenous and poligenic uranium deposits. Processes of uranium ore-formation under the conditions of low and high degrees of metamorphism are considered. On the basis of separate types of deposits shown is the possibility of mobilization, transfer and concentration of ore substance, its transformation from primary to secondary forms. Metamorphous and ultrametamorphous deposits are formed as a result of ore element translocation within considerable distances under the effect of endogenous solutions and their concentration in favourable structures. Conclusions on the effect of lithogenesis and metamorphism processes on the ore formation are substantiated by field observations, analyses (including methods of isotopic geochemistry) as well as by experiments

Study of the metamorphic belts and tectonics; Henseitai kenkyu to tectonics

Energy Technology Data Exchange (ETDEWEB)

Watanabe, T. [Hokkaido University, Sapporo (Japan)

1997-10-25

Study of metamorphic belts and tectonics is introduced. Minerals supposedly originating in the transitional zone and the lower mantle, that is, inclusions in diamond in kimberlite, are deemed to carry information about the depth level of 670km and lower. The place of origin of peridotite, Alpe Arami of Switzerland, is again estimated at a level of 300km or deeper. In the tectonic cross section in this region, the oceanic crust is bent and folded, and such a structure enables the supposition that fragments off the transitional zone may be carried upward to the ground surface. This region is now being limelighted, with plume tectonics enjoying popularity. The split of Pangaea is related with the ascent of plume. In the eastern part of Australia, there are alkali rocks attributable to the plume that was supposedly active at the end of the Proterozoic. Zircon U-Pb dating by SHRIMP offers a new approach to the tectonics of metamorphic rocks, and is reinforcing the position of metamorphic petrology relative to the study of collision and split of continents. 64 refs., 10 figs.

Metamorphic core complex formation by density inversion and lower-crust extrusion.

Science.gov (United States)

Martinez, F; Goodliffe, A M; Taylor, B

2001-06-21

Metamorphic core complexes are domal uplifts of metamorphic and plutonic rocks bounded by shear zones that separate them from unmetamorphosed cover rocks. Interpretations of how these features form are varied and controversial, and include models involving extension on low-angle normal faults, plutonic intrusions and flexural rotation of initially high-angle normal faults. The D'Entrecasteaux islands of Papua New Guinea are actively forming metamorphic core complexes located within a continental rift that laterally evolves to sea-floor spreading. The continental rifting is recent (since approximately 6 Myr ago), seismogenic and occurring at a rapid rate ( approximately 25 mm yr-1). Here we present evidence-based on isostatic modelling, geological data and heat-flow measurements-that the D'Entrecasteaux core complexes accommodate extension through the vertical extrusion of ductile lower-crust material, driven by a crustal density inversion. Although buoyant extrusion is accentuated in this region by the geological structure present-which consists of dense ophiolite overlaying less-dense continental crust-this mechanism may be generally applicable to regions where thermal expansion lowers crustal density with depth.

Age and duration of eclogite-facies metamorphism, North Qaidam HP/UHP terrane, Western China

Science.gov (United States)

Mattinson, C.G.; Wooden, J.L.; Liou, J.G.; Bird, D.K.; Wu, C.L.

2006-01-01

Amphibolite-facies para-and orthogneisses near Dulan, at the southeast end of the North Qaidam terrane, enclose minor eclogite and peridotite which record ultra-high pressure (UHP) metamorphism associated with the Early Paleozoic continental collision of the Qilian and Qaidam microplates. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. SHRIMP-RG U-Pb and REE analyses of zircons from four eclogites yield weighted mean ages of 449 to 422 Ma, and REE patterns (flat HREE, no Eu anomaly) and inclusions of garnet, omphacite, and rutile indicate these ages record eclogite-facies metamorphism. The coherent field relations of these samples, and the similar range of individual ages in each sample suggests that the ???25 m.y. age range reflects the duration of eclogite-facies conditions in the studied samples. Analyses from zircon cores in one sample yield scattered 433 to 474 Ma ages, reflecting partial overlap on rims, and constrain the minimum age of eclogite protolith crystallization. Inclusions of Th + REE-rich epidote, and zircon REE patterns are consistent with prograde metamorphic growth. In the Lu??liang Shan, approximately 350 km northwest in the North Qaidam terrane, ages interpreted to record eclogite-facies metamorphism of eclogite and garnet peridotite are as old as 495 Ma and as young as 414 Ma, which suggests that processes responsible for extended high-pressure residence are not restricted to the Dulan region. Evidence of prolonged eclogite-facies metamorphism in HP/UHP localities in the Northeast Greenland eclogite province, the Western Gneiss Region of Norway, and the western Alps suggests that long eclogite-facies residence may be globally significant in continental subduction/collision zones.

Argentina: Background and U.S. Relations

Science.gov (United States)

2008-11-05

Comercio Internacional, Y Culto, Comunicado de la Cancillería Argentina, September 11, 2008. 43 A. Rebossio, "Fernández Acusa al FBI de Desestablizar...Argentina," El País (Madrid), September 13, 2008. 44 “Argentina Slams Witness in Cash Suitcase Scandal,” Associated Press Newswires, November 4, 2008

Climatology of hail in Argentina

Science.gov (United States)

Mezher, Romina N.; Doyle, Moira; Barros, Vicente

2012-10-01

The annual cycle, annual and seasonal frequency and geographical distribution of hail in Argentina during the 1960-2008 period are examined. Eight regions covering the whole territory were defined based on the correlation of the mean annual hail frequency between all weather stations. Regions lying between 30° and 40°S as well as those dominated by mountains present the highest hail frequencies in Argentina. The eastern and coastal areas of the country experience hail events mainly during springtime but they may start in late winter and continue through the beginning of summer. Events in western and central Argentina also predominate in spring but the maximum frequencies are observed during summer months. Trends in the annual number of hail events calculated for each region indicate that events in northwestern and northeastern Argentina have been increasing as well as in southern Patagonia. On the other hand, in central Argentina, southern Buenos Aires-La Pampa, northern Buenos Aires-Litoral and northern Patagonia trends are negative and statistically significant in the first two regions, basically by the decrease of events during spring and summer.

Petrology and geochemistry of the Los Cuartos granite, Tafi del Valle, Tucuman, northwest of Argentina: its integration to the regional magmatic layout; Petrologia y geoquimica del granito Los Cuartos, Tafi del Valle, Tucuman, noroeste de Argentina: integracion al esquema magmatico regional

Energy Technology Data Exchange (ETDEWEB)

Lopez, J.P.; Bellos, L.I.

2010-07-01

Los Cuartos Granite crops out on the western flank of the Cumbres Calchaquies, east of Tafi del Valle, Tucuman Province, Argentina. It has a granitic to granodioritic composition, of two micas, being biotite dominant. The granite is medium grained and inequigranular, with rare K-feldspar megacrysts. It contains host-rock xenoliths with different degrees of assimilation. The granite intrusion produced contact metamorphism in the surrounding basement, with development of andalucite porphyroblasts and poikiloblastic biotite. The granite is calk-alkaline and peraluminous, and is K- and P-rich and Ca- and Napoor compared to other granitoids of the region. The pluton shows late-tectonic features with regard to the regional deformation. The granite possibly intruded during the Ordovician (Famatinian Cycle) and its emplacement was structurally controlled by the Tafi Megafracture. Los Cuartos Granite and other intrusive bodies of the region share similar petrographical, geochemical, structural and geochronological characteristics. (Author).

Operating practical experience at Argentina; Experiencia practica operativa en la Argentina

Energy Technology Data Exchange (ETDEWEB)

Quihillalt, Oscar [Nucleoelectria Argentina S.A., Buenos Aires (Argentina)

1998-12-31

Operating experiences of Atucha-1 and Embalse Nuclear Power Plants were discussed in this work. The technical and economic aspects, such as reliability, availability, personnel training, operating costs, prices and market, which exercise influence upon Argentina nuclear energy policy, mainly on the power electric generation by nuclear power plants were considered. Finally the current status of the nucleoelectric sector in Argentina and forecasting were analysed. 3 figs., 5 tabs.

Medical revolution in Argentina.

Science.gov (United States)

Ballarin, V L; Isoardi, R A

2010-01-01

The paper discusses the major Argentineans contributors, medical physicists and scientists, in medical imaging and the development of medical imaging in Argentina. The following are presented: history of medical imaging in Argentina: the pioneers; medical imaging and medical revolution; nuclear medicine imaging; ultrasound imaging; and mathematics, physics, and electronics in medical image research: a multidisciplinary endeavor.

New data on tectono-metamorphic evolution of the Peri-Trasmontano domain (Schistose Domain) in Northeastern Portugal

International Nuclear Information System (INIS)

Dias da Silva, I.; Gonzalez Clavijo, E.

2010-01-01

Under the main Tras-os-Montes thrust plane, in the easternmost region of the Morais Allochthonous Complex, a geologic unit has been identified. It shows syn-tectonic S 2 -related andalusite blastesis, representative of low pressure thermal metamorphism. In the studied sector this metamorphism affects essentially the black slaty lithologies present in Neoproterozoic to Silurian formations. This kind of thermal metamorphism is easily distinguishable from the late to post S 3 plutonic-related metamorphism, due to the existence of evidence of syn kinematic mineral blastesis with rotation and boudinage, synchronously with S 2 development. Syn-kinematic andalusite blastesis seems to affect only the autochthonous Central Iberian Zone rocks and it could be associated to crustal extensional phenomena like the ones identified in the Tormes Gneissic Dome. It is proposed that at least part of this andalusite blast generation could have a distinct origin, reflecting earlier low pressure thermal metamorphic events in inner Variscan orogen zones that were tectonically imbricated to present coordinates during the second Variscan phase. The vertical proximity of only a few hundred meters between extensional structures, to the East, and the compressive ones, to the West of the studied sector, could justify the presence of both pre- and syn-S 2 andalusite blasts inside the above mentioned tectono-metamorphic unit. The kinematic criteria (top to SE) are consistent with the ones of the Variscan synorogenic extensional structures placed nearby to the SE, pointing to a possible genetic relation with those crustal thinning processes. (Author) 42 refs.

The Katmandu and Gosainkund nappes, central Nepal Himalaya (cartography, structure, metamorphism, geochemistry and radio-chronology)

International Nuclear Information System (INIS)

Rai, S.M.

1998-10-01

In central Nepal, a multidisciplinary study has been carried out to characterize and distinguish the crystalline nappes of Katmandu and Gosainkund from the Midland formations. Two principal deformations are recorded: one ductile, syn-metamorphic, marked by microstructures (stretching lineation, S-C structures, etc. ), another, post-metamorphic, recorded by an anticline, roughly EW -directed, and by NNE-SSW -directed folds. The syn-metamorphic P-T conditions show differences between Katmandu Crystalline Nappe (900-720 MPa; 700-480 deg C) and Gosainkund Crystalline Nappe (890-580 MPa; 750-590 deg C). They exhibit well preserved inverted metamorphism between the Upper Midland Formations (750 Mpa; 560 deg C) and the Gosainkund Nappe. In central Nepal, the augen gneisses and the 'Lesser Himalayan' Cambro-Ordovician granites bear similar petrographic and geochemical characteristics which suggest a common origin. However, the geological setting and age of the Proterozoic Ulleri augen gneiss rule out correlation with these formations. 40 Ar/ 39 Ar analyses of muscovite, indicate cooling ages younger from south to north: 22 to 13 Ma in the Katmandu Nappe, 16 to 5 Ma in the Gosainkund Nappe, and 12 to 6 Ma in the Midland Formation. The principal points summarized by this study are the following: clear distinction between two nappes marked by their litho-stratigraphy and metamorphism; the ductile movement of MCT in the north of Katmandu is blocked since approximately 25 Ma; the late emplacement and late or common post metamorphic history of the two nappes; but earlier cooling history of the Katmandu nappe; the present uplift of the Katmandu region, underlined by the intense micro-seismicity, concerns indifferently the two nappes that form a single tectonic block at present; the combined uplift of the two nappes is due to the displacement on a ramp of major decollement surface. (author)

Post-peak metamorphic evolution of the Sumdo eclogite from the Lhasa terrane of southeast Tibet

Science.gov (United States)

Cao, Dadi; Cheng, Hao; Zhang, Lingmin; Wang, Ke

2017-08-01

A reconstruction of the pressure-temperature-time (P-T-t) path of high-pressure eclogite-facies rocks in subduction zones may reveal important information about the tectono-metamorphic processes that occur at great depths along the plate interface. The majority of studies have focused on prograde to peak metamorphism of these rocks, whereas after-peak metamorphism has received less attention. Herein, we present a detailed petrological, pseudosection modeling and radiometric dating study of a retrograded eclogite sample from the Sumdo ultrahigh pressure belt of the Lhasa terrane, Tibet. Mineral chemical variations, textural discontinuities and thermodynamic modeling suggest that the eclogite underwent an exhumation-heating period. Petrographic observations and phase equilibria modeling suggest that the garnet cores formed at the pressure peak (∼2.5 GPa and ∼520 °C) within the lawsonite eclogite-facies and garnet rims (∼1.5 GPa and spans an interval of ∼7 million years, which is a minimum estimate of the duration of the eclogite-facies metamorphism of the Sumdo eclogite.

Teaching Igneous and Metamorphic Petrology Through Guided Inquiry Projects

Science.gov (United States)

McMillan, N. J.

2003-12-01

Undergraduate Petrology at New Mexico State University (GEOL 399) has been taught using three, 5-6 week long projects in place of lectures, lab, and exams for the last six years. Reasons for changing from the traditional format include: 1) to move the focus from identification and memorization to petrologic thinking; 2) the need for undergraduate students to apply basic chemical, structural, and field concepts to igneous and metamorphic rocks; 3) student boredom in the traditional mode by the topic that has captivated my professional life, in spite of my best efforts to offer thrilling lectures, problems, and labs. The course has three guided inquiry projects: volcanic, plutonic, and pelitic dynamothermal. Two of the rock suites are investigated during field trips. Each project provides hand samples and thin sections; the igneous projects also include whole-rock major and trace element data. Students write a scientific paper that classifies and describes the rocks, describes the data (mineralogical and geochemical), and uses data to interpret parameters such as tectonic setting, igneous processes, relationship to phase diagrams, geologic history, metamorphic grade, metamorphic facies, and polymetamorphic history. Students use the text as a major resource for self-learning; mini-lectures on pertinent topics are presented when needed by the majority of students. Project scores include evaluation of small parts of the paper due each Friday and participation in peer review as well as the final report. I have found that petrology is much more fun, although more difficult, to teach using this method. It is challenging to be totally prepared for class because students are working at different speeds on different levels on different aspects of the project. Students enjoy the course, especially the opportunity to engage in scientific investigation and debate. A significant flaw in this course is that students see fewer rocks and have less experience in rock classification

Radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico with annotated bibliography

International Nuclear Information System (INIS)

McLemore, V.T.

1982-02-01

The primary objectives of this report are to list known radioactive occurrences in veins and igneous and metamorphic rocks in New Mexico, and to provide an annotated bibliography of geologic reports concerning these regions. Only plutonic, metamorphic, vein, and Precambrian quartz-pebble conglomerate uranium deposits are considered in this report; other nonsandstone uranium deposits (such as shale, limestone, phosphorite, coal, evaporative precipitates, and fossil placer deposits) will be considered at a later time. These objectives were achieved through a literature search. Some field examinations of some of the radioactive occurrences have been completed. A table of known radioactive occurrences in veins and igneous and metamorphic rocks was compiled from the literature (Appendix I)

Argentina's nuclear red herring

International Nuclear Information System (INIS)

Perera, J.

1983-01-01

The article deals with Argentina's nuclear power programme over the last 30 years, including the country's efforts to be nuclear independent of the United States, as well as its aspirations to be a nuclear supplier to latin America. The latter policy on economic, rather than military grounds for nuclear weapons, has led to Argentina's decision to build a uranian enrichment plant. (U.K.)

A versatile digitally-graded buffer structure for metamorphic device applications

Science.gov (United States)

Ma, Yingjie; Zhang, Yonggang; Chen, Xingyou; Gu, Yi; Shi, Yanhui; Ji, Wanyan; Du, Ben

2018-04-01

Exploring more effective buffer schemes for mitigating dislocation deficiencies is the key technology towards higher performance metamorphic devices. Here we demonstrate a versatile metamorphic grading structure consisting of 38-period alternated multilayers of In0.52Al0.48As and In0.82Al0.18As on InP substrate, thicknesses of which in each period were gradually varied in opposite directions from 48.7 and 1.3 nm to 1.3 and 48.7 nm, respectively, akin to a digital alloy. Both preferentially dislocation nucleation and blocking of threading dislocation transmission are observed near the In0.82Al0.18As/In0.52Al0.48As interfaces, which help relax the strain and lower the residual defect density. A 2.6 μm In0.83Ga0.17As pin photodetector is fabricated on this pseudo-substrate, attaining a low dark current density of 2.9  ×  10‑6 A cm‑2 and a high detectivity of 1.8  ×  1010 cmHz1/2W‑1 at room temperature, comparable with the states of the art that on linearly-graded buffer layers. These results indicate such digitally-graded buffer structures are promising for enhancing performances of metamorphic devices, and can be easily generalized to other lattice-mismatched material systems.

History of radiobiology in Argentina

International Nuclear Information System (INIS)

Mayo, Jose

2004-01-01

Radiobiology is a multidisciplinary science dealing with ionising radiation effects on biological material. The history of Radiobiology begins in Germany and France around 1886. Radiobiology was introduced in Argentina in 1926 at the Institute of Oncology Angel H. Roffo as a biomedical research branch. Later on in 1957 was incorporated at the National Atomic Energy Commission (CNEA) of Argentina as a result of the newly started nuclear activities in Argentina. Prior that time no Radiobiology research existed in Argentina. To fill this need a Project to create new laboratories was elaborated by the CNEA. New laboratories in Radiobiodosimetry, Cellular Radiobiology, Radiopathology, Radiomicrobiology, Genetics and Somatic Effects were created. Human resources on different areas of Radiobiology were formed with the assistance of IAEA. With professional and technical personnel specialized in Radiobiology at the beginning of the 1970 decade, the transference of fundamental and applied research to others laboratories started. (author)

Geología de la parte sur de la Sierra de San Luis y granitoides asociados, Argentina

Directory of Open Access Journals (Sweden)

Llambías, E. J.

1992-12-01

Full Text Available The lower Palaeozoic basement of the southern part of Sierra de San Luis, Argentina, is made up of metamorphic rocks, granitoids and ultramafic rocks. The metamorphic grade ranges from the lower limit of greenschist facies through the upper limit of amphibolite facies, in apparent transition. The lower grade metamorphic rocks include slates, metavolcanics, metaconglomerates, quartzites and phyllites. Rocks with intermediate metamorphism are biotite-quartz-oligoclase schists with abundant pegmatoid veins. The higher grade metamorphism is represented by gneisses, amphibolites and migmatites, to which mafic and ultramafic bodies are associated. Three deformation phases have been recognized, being the last one (D3, of ordovician age, responsible of the most marked structures.The granitoids were grouped into pre-, syn- and post-kynematic bodies respect to D3. The pre-kynematic granitoids are located within the belt of lower grade metamorphic rocks and are composed of tonalites, granodiorites and monzogranites, strongly deformed. Their age is unknown. The syn-kynematic bodies are mainly garnet-moscovite-bearing leucogranodiorites. They show low thermal and rheological contrasts respect to the country rocks, and the age is 454 ± 21 m.a. The post-kynematic granitoids are mainly monzogranites with K-feldspar megacrysts and abundant sphene. They are subcircular and discordant, and are associated with an extensional regime. Their age is comprised between 423 and 320 m.a., and corresponds to the end of the Famatinian cycle.El basamento cristalino de la parte sur de la Sierra de San Luis, de edad Paleozoico Inferior, está constituido por rocas metamórficas, granitoides y rocas ultramáficas. El grado de metamorfismo varía desde la parte baja de esquistos verdes hasta la parte alta de la facies anfibolita, siendo sus relaciones de aparente transicionalidad. Las rocas con menor grado metamórfico consisten en pizarras, metavolcanitas, metaconglomerados

Crisis de la prensa Argentina

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Federico Rey Lennon

2015-01-01

Full Text Available La magnitud de la crisis económica Argentina es enorme y difícil saber hasta cuando se extenderá, agravada por una situación política frágil. La actual recesión ha hecho caer la inversión publicitaria a los niveles más bajos de los últimos años. De 1997 al 2001 la circulación de la prensa Argentina cayó en el 36 por ciento. El riesgo en Argentina es la eventual extranjerización de casi todos los medios de comunicación.

contact metamorphism in the supracrustal rocks of the sukumaland ...

African Journals Online (AJOL)

Mgina

University of Dar es Salaam, College of Natural and Applied Sciences, Department of Geology,. P. O. Box 35052, Dar es Salaam, Tanzania ... bounded by rational crystal faces (decussate texture). Keywords. Contact metamorphism, intrusions ..... electron microbeam X-ray analysis of thick polished materials, thin films and.

Gneiss Macuira: tectonic evolution of Paleozoic metamorphic rocks of the Alta Guajira, Colombia

International Nuclear Information System (INIS)

Lopez I; A Julian; Zuluaga C; A, Carlos

2012-01-01

The Macuira Gneiss is a Paleozoic metamorphic unit that outcrops in the Simarua, Jarara and Macuira ranges, Alta Guajira. It is composed by a lithologies metamorphosed under amphibolite facies P-T conditions and consist of amphibolitic and quartz feldspathic gneisses, amphibolites, schists, pegmatites, calc-silicated rocks and marbles, with migmatization evidences in gneisses and amphibolites. Five foliations (S1-5) and three folding events (F1-3) were identified and interpreted as product of two metamorphic events, developed in a progressive barrovian metamorphic gradient of intermediate pressure with intermediate P-T ratio, interpreted as product of continental collision tectonics. This unit is important in understanding of the tectonic evolution of the Alta Guajira and Caribbean because it records different deformational phases pre-, syn- and post-migmatitic, that could be related with different tectonic episodes: the first associated with the collision between Laurasia and Gondwana (Alleghanian Orogeny - Late Paleozoic), and the second related with the Caribbean Plate evolution (Andean Orogeny - Meso-Cenozoic).

Coccocypselum pulchellum (Rubiaceae, nuevo registro para Argentina

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Elsa L. Cabral

2007-01-01

Full Text Available Se cita Coccocypselum pulchellum por primera vez para Argentina, en Predio Guaraní, Misiones. Esta es la tercera especie de Coccocypselum registrada para la flora de Argentina junto con C. hasslerianum y C. lanceolatum. Se incluyen descripciones, ilustraciones y una clave para reconocer las tres especies argentinas de Coccocypselum.

Uranium, rare metals, and granulite-facies metamorphism

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Michel Cuney

2014-09-01

The Tranomaro metasomatized marbles recrystallizing under granulite-facies conditions represent a demonstrative example of fluid transfer from granulite-facies supracrustals to traps represented by regional scale skarns. Such fluids may be at the origin of the incompatible element enrichment detected in leucosomes of migmatites from St Malo in Brittany (France and Black Hills in South Dakota. The northern French Massif Central provides us with an example of a potential association between incompatible element enrichment of granitic melts and granulite-facies metamorphism. U- and F-enriched fine-grained granites are emplaced along a crustal scale shear zone active during the emplacement within the St Sylvestre peraluminous leucogranitic complex. We propose that during granulite-facies metamorphism dominated by carbonic waves in a deep segment of the continental crust, these shear zones control: (i the percolation of F-, LILE-, rare metal-rich fluids liberated primarily by the breakdown of biotite; (ii the enhancement of partial melting by F-rich fluids at intermediate crustal levels with the generation of F-, LILE-, rare metal-rich granitic melts; (iii their transfer through the crust with protracted fractionation facilitated by their low viscosity due to high F-Li contents; and finally (iv their emplacement as rare metal intrusions at shallow crust levels.

Telescoping metamorphic isograds: Evidence from 40Ar/39A dating in the Orange-Milford belt, southern Connecticut

Science.gov (United States)

Kunk, Michael J.; Walsh, Gregory J.; Growdon, Martha L.; Wintsch, Robert P.

2013-01-01

New 40Ar/39Ar ages for hornblende and muscovite from the Orange-Milford belt in southern Connecticut reflect cooling from Acadian amphibolite facies metamorphism between ∼380 to 360 Ma followed by retrograde recrystallization of fabric-forming muscovite and chlorite during lower greenschist facies Alleghanian transpression at ∼280 Ma. Reported field temperature and pressure gradients are improbably high for these rocks and a NW metamorphic field gradient climbing from chlorite-grade to staurolite-grade occurs over less than 5 km. Simple tilting cannot account for this compressed isograd spacing given the geothermal gradient of ∼20 °C/km present at the time of regional metamorphism. However, post-metamorphic transpression could effectively telescope the isograds by stretching the belt at an oblique angle to the isograd traces. Textures in the field and in thin section reveal several older prograde schistosities overprinted by lower greenschist facies fabrics. The late cleavages commonly occur at the scale of ∼100 μm and these samples contain multiple age populations of white mica. 40Ar/39Ar analysis of these poly-metamorphic samples with mixed muscovite populations yield climbing or U-shaped age spectra. The ages of the low temperature steps are late Paleozoic, while the ages of the older steps are late Devonian. These results support our petrologic interpretation that the younger cleavage developed under metamorphic conditions below the closure temperature for Ar diffusion in muscovite, that is, in the lower greenschist facies. The correlation of a younger regionally reproducible age population with a pervasive retrograde muscovite ± chlorite cleavage reveals an Alleghanian (∼280 Ma) overprint on the Acadian metamorphic gradient (∼380 Ma). Outcrop-scale structures including drag folds and imbricate boudins suggest that Alleghanian deformation and cleavage development occurred in response to dextral transpression along a northeast striking boundary

Analysis of lineament swarms in a Precambrian metamorphic rocks

Indian Academy of Sciences (India)

Addressing the geologic significance of lineaments and their correlation with joints/fractures is still unclear. The present study attempts to analyse the lineament swarms developed in a Precambrian metamorphic terrain in India using both unfiltered and filtered techniques. The unfiltered analysis technique shows that the ...

Peak metamorphic temperatures from cation diffusion zoning in garnet

DEFF Research Database (Denmark)

Smit, Matthijs Arjen; Scherer, Erik; Mezger, Klaus

2013-01-01

) to develop a tool that uses the diffusion zoning of these cations in garnet to constrain peak temperature conditions for garnet-bearing rocks. The thermometric approach was externally tested by applying it to garnet crystals from various metamorphic terranes worldwide and comparing the results to published...

Semantically Enabling Knowledge Representation of Metamorphic Petrology Data

Science.gov (United States)

West, P.; Fox, P. A.; Spear, F. S.; Adali, S.; Nguyen, C.; Hallett, B. W.; Horkley, L. K.

2012-12-01

More and more metamorphic petrology data is being collected around the world, and is now being organized together into different virtual data portals by means of virtual organizations. For example, there is the virtual data portal Petrological Database (PetDB, http://www.petdb.org) of the Ocean Floor that is organizing scientific information about geochemical data of ocean floor igneous and metamorphic rocks; and also The Metamorphic Petrology Database (MetPetDB, http://metpetdb.rpi.edu) that is being created by a global community of metamorphic petrologists in collaboration with software engineers and data managers at Rensselaer Polytechnic Institute. The current focus is to provide the ability for scientists and researchers to register their data and search the databases for information regarding sample collections. What we present here is the next step in evolution of the MetPetDB portal, utilizing semantically enabled features such as discovery, data casting, faceted search, knowledge representation, and linked data as well as organizing information about the community and collaboration within the virtual community itself. We take the information that is currently represented in a relational database and make it available through web services, SPARQL endpoints, semantic and triple-stores where inferencing is enabled. We will be leveraging research that has taken place in virtual observatories, such as the Virtual Solar Terrestrial Observatory (VSTO) and the Biological and Chemical Oceanography Data Management Office (BCO-DMO); vocabulary work done in various communities such as Observations and Measurements (ISO 19156), FOAF (Friend of a Friend), Bibo (Bibliography Ontology), and domain specific ontologies; enabling provenance traces of samples and subsamples using the different provenance ontologies; and providing the much needed linking of data from the various research organizations into a common, collaborative virtual observatory. In addition to better

Petrographic and EMP study of metamorphic rocks from the Variscan basement of Dinarides (Vranica Mountains, Bosnia and Herzegovina)

Energy Technology Data Exchange (ETDEWEB)

Hrvanovic, S [Department of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia)

2012-04-25

The Vranica Mountains are located in the middle part of Bosnia and Herzegovina or in the southeastern part of the Mid - Bosnian schist Mountains (MBSM). The Mid - Bosnian schist Mountains represent one of the largest allochtonous Paleozoic terranes in the Dinarides. This region is characterized by a multistage geodynamic evolution. The presented results concern Variscan metamorphism of the Silur-Devonian protolith formations that occurred mainly during the Early Carboniferous in LT/MP greenschist facies. Petrographical description of metamorphic rocks is completed by EMPA of muscovite, chlorite and chloritoid. The Early Alpine metamorphic overprint is related to the closure of a Tethyan Basin and Early Cretaceous collision of the Adria microplate with the Tissia-Moesia continental Blocks. The Neo-Alpine metamorphic overprint occurred due to the collision of the African and Euroasian Plates. (authors)

The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

Science.gov (United States)

Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari

2011-04-01

The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

Thermobarometry and electron-microprobe Th-U-Pb monazite dating in garnet metapelites from the Capelinha Formation, Aracuai Orogen, Brazil

Energy Technology Data Exchange (ETDEWEB)

Queiroga, Glaucia Nascimento; Martins, Maximiliano de Souza; Castro, Marco Paulo de; Jordt-Evangelista, Hanna; Silva, Ana Lucia da, E-mail: glauciaqueiroga@yahoo.com.br, E-mail: maximilianomartins@yahoo.com.br, E-mail: marco_pcastro@yahoo.com, E-mail: hanna@degeo.ufop.br, E-mail: alucia.silva@hotmail.com [Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG (Brazil). Escola de Minas. Departamento de Geologia; Pedrosa-Soares, Antonio Carlos, E-mail: pedrosa@igc.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Instituto de Geociencias. Departamento de Geologia; Schulz, Bernhard, E-mail: bernhard.schulz@mineral.tu-freiberg.de [TU Bergakademie - Institute of Mineralogy, Freiberg - Saxony (Germany)

2016-01-15

The Capelinha Formation (Macaubas Group) consists of a lower quartzitic unit with metamafic intercalations and an upper metapelitic sequence. It occurs in a complex tectono-metamorphic sector of the Aracuai orogen, where post-collisional collapse-related structures superimposed collisional structures. The garnet-bearing assemblages started crystallization in the collisional deformation stage that formed the main regional foliation around 570 Ma. Garnet porphyroblasts display a well developed growth zonation of Fe-Mg-Ca-Mn and show, from core to rim, increasing almandine and pyrope contents in contrast with decreasing grossular and spessartine contents. Mineral relations and microstructures provide criteria for local equilibria and a structurally controlled application of geothermobarometry based on cation exchange and net transfer reactions. The P-T values calculated from cores to rims of garnets, aligned along clockwise trends, resulted in increasing temperatures (from 500 deg C up to 620 deg C) under decompression conditions (from 8.0 kbar to 4.5 kbar). The Th-UPb dating of homogeneous monazites by electron microprobe revealed a recrystallization period at around 490 - 480 Ma. These ages can be related to the tectono-thermal event associated with the gravitational collapse, constraining the youngest time limit for metamorphic processes in the Aracuai orogen. (author)

Uranium deposits in the metamorphic basement of the Rouergue massif. Genesis and extension of related albitization processes

International Nuclear Information System (INIS)

Schmitt, J.M.

1982-02-01

Albitization processes in the Rouergue metamorphic basement, probably Permian aged is evidenced. Late development of uranium orebodies occured within albitized zones. The detection of the latter serves as a highly valuable indirect guide for prospecting this type of deposits in a metamorphic basement [fr

Uranium cycle and tectono-metamorphic evolution of the Lufilian Pan-African orogenic belt (Zambia)

International Nuclear Information System (INIS)

Eglinger, Aurelien

2013-01-01

Uranium is an incompatible and lithophile element, and thus more concentrated in silicate melt produced by the partial melting of the mantle related to continental crust formation. Uranium can be used as a geochemical tracer to discuss the generation and the evolution of continental crust. This thesis, focused on the Pan-African Lufilian belt in Zambia, combines structural geology, metamorphic petrology and thermos-barometry, fluid inclusions, geochemistry and geochronology in order to characterize the uranium cycle for this crustal segment. Silici-clastic and evaporitic sediments have been deposited within an intra-continental rift during the dislocation of the Rodinia super-continent during the early Neo-proterozoic. U-Pb ages on detrital zircon grains in these units indicate a dominant Paleo-proterozoic provenance. The same zircon grains show sub-chondritic εHf (between 0 and -15) and yield Hf model ages between ∼2.9 and 2.5 Ga. These data suggest that the continental crust was generated before the end of the Archean (< 2.5 Ga) associated with uranium extraction from the mantle. This old crust has been reworked by deformation and metamorphism during the Proterozoic. Uranium has been re-mobilized and reconcentrated during several orogenic cycles until the Pan-African orogeny. During this Pan-African cycle, U-Pb and REY (REE and Yttrium) signatures of uranium oxides indicate a first mineralizing event at ca. 650 Ma during the continental rifting. This event is related to late diagenesis hydrothermal processes at the basement/cover interface with the circulation of basinal brines linked to evaporites of the Roan. The second stage, dated at 530 Ma, is connected to metamorphic highly saline fluid circulations, synchronous to the metamorphic peak of the Lufilian orogeny (P=9±3 kbar; T=610±30 deg. C). These fluids are derived from the Roan evaporite dissolution. Some late uranium re-mobilizations are described during exhumation of metamorphic rocks and their

Nuclear Activities in Argentina, 2010

International Nuclear Information System (INIS)

Ferreri, J.C.; Ferreri, J.C.; Clausse, A.; Clausse, A.; Clausse, A.; Ordonez, J.P.; Mazzantini, O.A.

2011-01-01

Nuclear activities in Argentina are restarted. After almost two decades of near stagnation, the governments political decision of August 2006 regarding electrical energy production, considered the nuclear option as a valid one to solve the problems of the growing demand of electrical energy. This decision triggered again the activities related to the finalization of the third nuclear power reactor (Atucha-II), now actively progressing, the construction of a prototype of the CAREM integral advanced reactor, the life extension of the Embalse CANDU nuclear power plant (NPP) and the studies for the emplacement of a fourth NPP in an appropriate site. In all those years of near stagnation, there were notable exceptions related to the design and construction of experimental and radioisotope production reactors, led by INVAP, a state-owned industry, which exported its production. The accompanying industries of nuclear fuel elements production also remained active, given the demand of the two active NPPs. Meanwhile, the National Atomic Energy Commission of Argentina continued the efforts on research and development that were at the base of the technological achievements of the nuclear activities in Argentina. Nuclear safety studies associated with Atucha II and Embalse NPPs and radiological safety were also a substantive part of the continued efforts by Nucleo-Electrica de Argentina SA and the Nuclear Regulatory Authority of Argentina

Argentina [Country report

International Nuclear Information System (INIS)

Ferreyra, R.

2005-01-01

The airborne geophysical surveys developed in Argentina are described. They have got more than 500.000 km 2 acquiring data for U, Th, K and total background activity. Other types of published data are also mentioned (satellite imagery, seismic hazard, climate, soil distributions, etc.). The availability of maps with the abundances of elements analyzed at the country and also at laboratories from Canada is described, as well as data of analysis of several elements at two study areas proposed at the outset of the project. The availability of process rate data and epidemiological data is also explained. Argentina intended fully to participate in the CRP at the outset of the project. Due, however, to external resource constraints imposed on the participating organization (Comision Nacional de Energia Atomica, CNEA), the level of participation had to be significantly reduced. Nonetheless, in the first period of the CRP, Argentina undertook to collate existing geological and geochemical information within the country, and began to define potential areas for site specific natural systems safety indicator studies. (author)

Gold, uranium and thorium in zones of greenschist displacement metamorphism

International Nuclear Information System (INIS)

Gavrilenko, B.V.; Savitskij, A.V.; Titov, V.V.

1987-01-01

Distribution of gold, uranium (bar and mobile) and thorium in 15 zones of greenschist dislocated metamorphism in different structures of the Karelo-Kola region carried out by geologic formations of the Early-Archean-Late-Proterozoic age has been studied. More than 200 samples of well core from 0-200 m depths have been analyzed. The results obtained testify to the increase of gold, uranium and less thorium content in zones of green-schist dislocated metamorphism in comparison with the enclosing rocks 1.4-3.1 times. The variation coefficient of gold, uranium and thorium content in green-schist dislocated tectonites increases 1.5-2.9 times. The correlation coefficient of Au/U mob. pair is +0.69, and Au/U bar pair -+0.87. Essential correlation between concentrations of all three elements in enclosing rocks is absent

Petrology of blueschist facies metamorphic rocks of the Meliata Unit

Directory of Open Access Journals (Sweden)

Faryad Shah Wali

1997-06-01

Full Text Available Meliata blueschists originated from basalts, limestones, pelites, psammitic and amphibolite facies basement rocks. Compositionally, the metabasalts have a geochemical signature mostly indicative of a transitional arc-MORB origin, but some mafic rocks having affinity with within plate basalts also present. The mafic blueschists consist of blue amphibole, epidote and albite, rarely also garnet, Na-pyroxene and chloritoid. Apart from phengite and quartz the metapelites and metapsammites contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, occasionally also Na-pyroxene and garnet. Amphibolite facies rocks contain relic garnet, plagioclase and hornblende, the latter two replaced by albite and blue amphibole, respectively. The zoning patterns of blue amphibole, garnet and chloritoid suggest their formation during prograde stage of metamorphism. P-T conditions of meta-morphism are estimated to be about 350-460 oC and 10-12 kbar.

La familia Cyatheaceae (Pteridophyta en Argentina The family Cyatheaceae (Pteridophyta in Argentina

Directory of Open Access Journals (Sweden)

Gonzalo J Marquez

2010-06-01

Full Text Available La familia Cyatheaceae comprende alrededor de 500 especies de helechos arborescentes. Su distribución es pantropical y en Argentina se encuentra representada por 4 especies, reunidas en los géneros Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens y C. delgadii. En este trabajo se presenta una actualización de la información disponible hasta el momento referente a estas especies. Se exponen microfotografías de las esporas, que presentan la superficie con lomos en Alsophila y con cordones en Cyathea. Se ilustran los indusios y escamas de la base de los pecíolos, que son de importancia fundamental para la diferenciación de las especies estudiadas. Asimismo se presenta un mapa de distribución y una clave de las especies que crecen en Argentina.The family Cyatheaceae comprises about 500 species of tree ferns. Their distribution is pantropical and in Argentina is represented by four species, grouped in genera Alsophila y Cyathea: A. setosa, A. odonelliana, C. atrovirens and C. delgadii. In this paper, an update of the available information of the mentioned species is presented. A key to diferentiate the species growing in Argentina, their descriptions and a distribution map are also given. Spores are ridged in Alsophila and with rodlets in Cyathea. Indusia and scales of petiole basis are also illustrated.

Eclogite facies relics and a multistage breakdown in metabasites of the KTB pilot hole, NE Bavaria: implications for the Variscan tectonometamorphic evolution of the NW Bohemian Massif

Science.gov (United States)

O'Brien, Patrick J.; Röhr, Christian; Okrusch, Martin; Patzak, Margarete

1992-11-01

Complex reaction textures in coronitic metagabbros and retrograded eclogites of the KTB pilot and an adjacent drilling provide evidence for a multistage metamorphic history in the Variscan basement of the NW Bohemian Massif. The eclogites show complete metamorphic recrystallization leaving no textural or mineral relics of their igneous precursors. In contrast, textural relics of the igneous protolith are still preserved in the metagabbros where the metamorphic overprint under high pressure conditions achieved only partial replacement of the initial assemblage plagioclase + augite + amphibole (+olivine or orthopyroxene?) + ilmenite to form the eclogite facies assemblage garnet + omphacite + kyanite + zoisite + quartz+rutile. The garnets in the metagabbros occur in the typical ‘necklace’ fashion at the borders between the original plagioclase and mafic phase domains. In the same rocks, omphacite formed by a topotactic reaction mechanism replacing igneous augite as well as in smaller grains at the margins of the texturally igneous clinopyroxene where it occurs without fixed orientation with respect to the relict phase. Both eclogites and metagabbros show a partial breakdown under high pressure granulite (transitional to high pressure amphibolite) facies conditions during which omphacite broke down to vermicular symplectites of diopside + plagioclase. A later pervasive medium pressure metamorphism under amphibolite facies conditions led to the development of assemblages dominated by hornblende + plagioclase+titanite: phases prevailing in the overwhelming majority of the surrounding metabasites. Subsequent vein-associated retrogression produced minerals typical of the greenschist to zeolite facies. All metamorphic stages may be represented in a single thin section but although the overall reaction sequence is apparent, the obvious disequilibrium in the rocks makes the use of conventional geothermobarometry difficult. However, calculations made by assuming an

Ammonium in Witwatersrand reefs: a possible indicator of metamorphic fluid flow

International Nuclear Information System (INIS)

Meyer, F.M.

1991-01-01

Ammonium concentrations and NH 4 + /K ratios in the Kimberley Reef indicate chemical interaction with metamorphic fluids. The data, although preliminary, also suggests a gold-ammonium association in that higher gold levels are related to higher NH 4 + /K ratios. Samples from the Ventersdorp Contact Reef are also hydrothermally altered but no ammonium was detected. The low ammonium concentrations suggest that over-printing by NH 4 -bearing metamorphic fluids was negligible. From this it is concluded that chemically different fluid systems must have been operative, probably at different times, during Witwatersrand history. It appears, therefore, that ammonium geochemistry is potentially useful in the study of fluid flow and related gold (re)distribution in Witwatersrand reefs. 17 refs., 2 figs., 1 tab

Amphiboles and their host rocks in the high-grade metamorphic Precambrin of Rogaland/Vest-Agder, Sw. Norway

NARCIS (Netherlands)

Dekker, A.G.C.

1978-01-01

In the high-grade metamorphic Precambrian of the Sirdal-¢rsdal area, Rogaland/Vest-Agder,south-west Norway, the Ca-amphiboles show a change in pleochroic colours, not only with changes in metamorphic grade, but also to some extend in bulk composition. A regional study was performed on the

Mida õpetab Argentina finantskriis? / Karsten Staehr

Index Scriptorium Estoniae

Staehr, Karsten, 1962-

2002-01-01

Norra majandusanalüütik kirjeldab Argentina majanduspoliitikat, analüüsib tehtud vigu ning hoiatab avatud majandusega Eestit võimalike tulevaste välisshokkide eest. Diagramm: SKP kasv ja üleüldine riigieelarve tasakaal 1991-2001 Argentinas

Evaluating the importance of metamorphism in the foundering of continental crust.

Science.gov (United States)

Chapman, Timothy; Clarke, Geoffrey L; Piazolo, Sandra; Daczko, Nathan R

2017-10-12

The metamorphic conditions and mechanisms required to induce foundering in deep arc crust are assessed using an example of representative lower crust in SW New Zealand. Composite plutons of Cretaceous monzodiorite and gabbro were emplaced at ~1.2 and 1.8 GPa are parts of the Western Fiordland Orthogneiss (WFO); examples of the plutons are tectonically juxtaposed along a structure that excised ~25 km of crust. The 1.8 GPa Breaksea Orthogneiss includes suitably dense minor components (e.g. eclogite) capable of foundering at peak conditions. As the eclogite facies boundary has a positive dP/dT, cooling from supra-solidus conditions (T > 950 ºC) at high-P should be accompanied by omphacite and garnet growth. However, a high monzodioritic proportion and inefficient metamorphism in the Breaksea Orthogneiss resulted in its positive buoyancy and preservation. Metamorphic inefficiency and compositional relationships in the 1.2 GPa Malaspina Pluton meant it was never likely to have developed densities sufficiently high to founder. These relationships suggest that the deep arc crust must have primarily involved significant igneous accumulation of garnet-clinopyroxene (in proportions >75%). Crustal dismemberment with or without the development of extensional shear zones is proposed to have induced foundering of excised cumulate material at P > 1.2 GPa.

Amphiboles and their host rocks in the high-grade metamorphic Precambrin of Rogaland/Vest-Agder, Sw. Norway

NARCIS (Netherlands)

Dekker, A.G.C.

1978-01-01

In the high-grade metamorphic Precambrian of the Sirdal-¢rsdal area, Rogaland/Vest-Agder,south-west Norway, the Ca-amphiboles show a change in pleochroic colours, not only with changes in metamorphic grade, but also to some extend in bulk composition. A regional study was performed on the amphiboles

RELATIONSHIP BETWEEN METAMORPHISM DEGREE AND LIBERATION SIZE OF COMPACT ITABIRITES FROM THE IRON QUADRANGLE

Directory of Open Access Journals (Sweden)

Rodrigo Fina Ferreira

2015-06-01

Full Text Available Iron ore exploited in Brazil can be classified into several lithological types which have distinct features. The progress of mining over time leads to scarcity of high grade iron ores, leading to the exploitation of poor, contaminated and compact ores. There is a growing trend of application of process flowsheets involving grinding to promote mineral liberation, essential condition for concentration processes. Several authors have correlated metamorphism processes of banded iron formations to mineralogical features observed on itabirites from the Iron Quadrangle, mainly the crystals size. This paper presents the implications of such variation in defining the mesh of grinding. Mineralogical characterization and grinding, desliming and flotation tests have been carried out with samples from two regions of the Iron Quadrangle subjected to different degrees of metamorphism. It was found a trend of reaching satisfactory liberation degree in coarser size for the itabirite of higher metamorphic degree, which has larger crystals. The flotation tests have confirmed the mineralogical findings.

Distributed consensus for metamorphic systems using a gossip algorithm for CAT(0) metric spaces

Science.gov (United States)

Bellachehab, Anass; Jakubowicz, Jérémie

2015-01-01

We present an application of distributed consensus algorithms to metamorphic systems. A metamorphic system is a set of identical units that can self-assemble to form a rigid structure. For instance, one can think of a robotic arm composed of multiple links connected by joints. The system can change its shape in order to adapt to different environments via reconfiguration of its constituting units. We assume in this work that several metamorphic systems form a network: two systems are connected whenever they are able to communicate with each other. The aim of this paper is to propose a distributed algorithm that synchronizes all the systems in the network. Synchronizing means that all the systems should end up having the same configuration. This aim is achieved in two steps: (i) we cast the problem as a consensus problem on a metric space and (ii) we use a recent distributed consensus algorithm that only make use of metrical notions.

SHRIMP U-Pb dating of detrital zircons in metamorphic rocks from northern Kyushu, western Japan

International Nuclear Information System (INIS)

Tsutsumi, Yukiyasu; Yokoyama, Kazumi; Terada, Kentaro; Sano, Yuji

2003-01-01

Radiometric ages of detrital zircons in psammitic schists from the Nagasaki, Kurume, Konoha and Kiyama areas, northern Kyushu, were obtained from 238 U/ 206 Pb ratio and isotopic compositions of Pb using a Sensitive High Resolution Ion Microprobe (SHRIMP II). Zircons from the Nagasaki, Kurume and Konoha areas show bimodal age distribution with peaks at ca. 1900 Ma and 250 Ma. It is suggested from this study that the older zircons were derived from Proterozoic landmass and the Korean Peninsula. Zircons from the Kiyama metamorphic rock show a different pattern with ages concentrated at 380-590 Ma. Such zircons are rare in rock samples from the Nagasaki, Kurume and Konoha areas, indicating that Kiyama rocks and a different origin than those from the other three areas. The youngest zircons from the Kiyama, Nagasaki, Kurume and Konoha areas show ages of 382±23 Ma, 238±13 Ma, 249±13 Ma, and 175±4 Ma, respectively, These data mark the upper age limit of their deposition. Since a continuous igneous activity occurred during the period from 300 to 170 Ma in Far East Asia, and the metamorphic age has been close to the zircon age of each area, these youngest ages for the Nagasaki, Kurume and Konoha areas are considered nearly contemporary to the depositional ages. An evaluation of the nature of metamorphism and available ages suggest the possibility that the Nagasaki metamorphic rocks as well as the schist from the Kurume area belong to the Suo zone of the Sangun belt, whereas the metamorphic rocks in the Konoha area may belong to the Ryoke belt or Suo zone of the Sangun belt. (author)

A widespread devonian methamorphic episode in northern Patagonia, Argentina

International Nuclear Information System (INIS)

Ostera, H.A.; Linares, E; Haller, M.J; Cagnoni, M.C.; Lopez de Luchi, M

2001-01-01

One of the greatest difficulties in Rb-Sr dating on metamorphic rocks is the lack of evidences of complete re-homogenization and the assumption of a common initial ratio for all the samples analyzed. The redistribution of parent-daughter elements and the concomitant partial or complete equilibration of the isotopic system could occur on mineral or regional size domains. This fact led to many authors to discard or disapprove the use of this method in metamorphic terranes. However, recent papers suggested that this opinion has been premature and that additional information could be obtained by the Rb-Sr method despite the difficulties that it implies (Patel et al., 1999). Many reports on well fitted Rb-Sr isochrons giving the age of metamorphism in regionally metamorphosed rocks, suggest that the Sr isotopic equilibrium can take place at different scales. This paper presents data and the Rb-Sr system behaviour from a metamorphic unit (Cushamen Formation) in the Northern Patagonia, as a contribution to elucidate the evolution of the North Patagonian Massif (au)

First data on Sm-Nd systematization of Khanka Massif metamorphic rocks, Primor'e

International Nuclear Information System (INIS)

Mishkin, M.A.; Khanchuk, A.I.; Zhuravlev, D.Z.; Lavrik, S.N.

2000-01-01

The age of the metamorphic rocks of the Khanka massif, Primor'e, is determined through the method of the Sm-Nd isotopic dating. The results of the isotopic studies on the amphibolites of the Nakhimov suite of the Khanka massif indicated that the rocks of this suite are not older than 1.7 billion years. The obtained age corresponds to the time of the amphibolite protolith formation, the source whereof is the moderately depleted mantle. The isotopic age of the amphibole and plagioclase mineral fractions constitutes 733 ± 25 mln years, which reflects the time of the Nakhimov suite rocks metamorphism [ru

Mobility enhancement in tensile-strained Ge grown on InAlP metamorphic templates

International Nuclear Information System (INIS)

Wang, Kai; Gong, Qian; Zhou, Haifei; Kang, Chuanzhen; Yan, Jinyi; Liu, Qingbo; Wang, Shumin

2014-01-01

We investigated the growth of tensile-strained Ge on InAlP metamorphic templates by gas source molecular beam epitaxy. Good control of biaxial tensile strain in the Ge layer was demonstrated in the range of 0.5–2.0% by adjusting the In content of the metamorphic template. It was found that the growth of Ge was layer-by-layer (2D) even under high tensile strain of 2.0%, resulting in a smooth surface with roughness less than 1.5 nm. Hall results showed that the electron mobility of Ge increased monotonically with tensile strain.

Communications received from Argentina and Brazil

International Nuclear Information System (INIS)

1989-01-01

The document reproduces the Joint Statement on Nuclear Policy signed by the President of Argentina and the President of Brazil on 29 November 1988 at Ezeiza, Argentina, concerning the decision of the two countries to undertake a joint fast breeder reactor project

Argentina

International Nuclear Information System (INIS)

2001-04-01

This economical study summarizes the energy situation of Argentina: energy institutions and policy, energy companies (oil, electricity, gas, coal), energy supplies (resources, power production, petroleum, natural gas), prices and tariffs, consumption, economical stakes and perspectives (investments, agreements, projects). Energy data for the 1971-1999 period are summarized in graphs and tables. (J.S.)

Argentina: a mature urbanization pattern.

Science.gov (United States)

Rofman, A B

1985-02-01

"This article describes the historical development of Argentina's cities, pointing out the traditional dominance of the 'centre-litoral' region and...[of] Buenos Aires. Recent trends such as the population increase in the southern region are described and demographic trends are related to economic developments. The article concludes by examining Argentina's contemporary urban patterns, including the current low rate of urbanization." excerpt

Argentina's radioactive waste disposal policy

International Nuclear Information System (INIS)

Palacios, E.

1986-01-01

The Argentina policy for radioactive waste disposal from nuclear facilities is presented. The radioactive wastes are treated and disposed in confinement systems which ensure the isolation of the radionucles for an appropriate period. The safety criteria adopted by Argentina Authorities in case of the release of radioactive materials under normal conditions and in case of accidents are analysed. (M.C.K.) [pt

Evaluation of defect density by top-view large scale AFM on metamorphic structures grown by MOVPE

Energy Technology Data Exchange (ETDEWEB)

Gocalinska, Agnieszka, E-mail: agnieszka.gocalinska@tyndall.ie; Manganaro, Marina; Dimastrodonato, Valeria; Pelucchi, Emanuele

2015-09-15

Highlights: • Metamorphic buffer layers of In{sub x}Ga{sub 1−x}As were grown by MOVPE and characterised by AFM and TEM. • It was found that AFM provides sufficient information to estimate threading defect density in metamorphic structures, even when significant roughness is present. • When planar-view TEM is lacking, a combination of cross-sectional TEM and large scale AFM can provide good evaluation of the material quality. • It is fast, cheap and non-destructive – can be very useful in development process of complicated structures, requiring multiple test growths and characterisation. - Abstract: We demonstrate an atomic force microscopy based method for estimation of defect density by identification of threading dislocations on a non-flat surface resulting from metamorphic growth. The discussed technique can be applied as an everyday evaluation tool for the quality of epitaxial structures and allow for cost reduction, as it lessens the amount of the transmission electron microscopy analysis required at the early stages of projects. Metamorphic structures with low surface defectivities (below 10{sup 6}) were developed successfully with the application of the technique, proving its usefulness in process optimisation.

New P-T and U-Pb constraints on Alpine Schist metamorphism in south Westland, New Zealand

International Nuclear Information System (INIS)

Scott, J.M.; Auer, A.; Muhling, J.R.; Czertowicz, T.A.; Cooper, A.F.; Billia, M.A.; Kennedy, A.K.

2015-01-01

Metamorphic mineral compositions of a staurolite-bearing greyschist from the middle reaches of the Moeraki River valley in south Westland reveal peak equilibration at c. 558±50 degrees C and c. 6.1±1.2 kbar. Two c. 83 Ma U-Pb monazite age populations from the cores of monazite-apatite-allanite-epidote corona structures in mylonitised schists from near Fox Glacier confirm that Alpine Schist metamorphism occurred during the Late Cretaceous. The published spread in Late Cretaceous metamorphic ages indicates that metamorphism was diachronous or was a protracted event. Further dating is required to pin down the cryptic transition into the Jurassic-Early Cretaceous metamorphosed Otago Schist, but the Alpine Schist must extend at least 11 km east of the Alpine Fault in south Westland and overprint the suture between the Pounamu and Rakaia terranes. The P-T-t results imply that the Late Cretaceous crust represented by portions of the Alpine Schist was probably of similar thickness to that beneath the Southern Alps today, but with dehydration and partial melting occurring near the base. The crust under Westland and Otago may be dry and therefore strong. (author).

LDC nuclear power: Argentina

International Nuclear Information System (INIS)

Tweedale, D.L.

1982-01-01

Argentina's 31-year-old nuclear research and power program makes it a Third World leader and the preeminent Latin American country. Easily accessible uranium fuels the heavy water reactor, Atucha I, which provides 10% of the country's electric power. Atucha II and III are under construction. Several domestic and international factors combined to make Argentina's program succeed, but achieving fuel-cycle independence and the capacity to divert fissionable material to military uses is a cause for some concern. 60 references

Metamorphic and tectonic evolution of the Greater Himalayan Crystalline Complex in Nyalam region, south Tibet

Science.gov (United States)

Wang, Jia-Min; Zhang, Jin-Jiang; Rubatto, Daniela

2016-04-01

Recent studies evoke dispute whether the Himalayan metamorphic core - Greater Himalayan Crystalline Complex (GHC) - was exhumed as a lateral crustal flow or a critical taper wedge during the India-Asia collision. This contribution investigated the evolution of the GHC in the Nyalam region, south Tibet, with comprehensive studies on structural kinematics, metamorphic petrology and geochronology. The GHC in the Nyalam region can be divided into the lower and upper GHC. Phase equilibria modelling and conventional thermobarometric results show that peak temperature conditions are lower in the lower GHC (~660-700°C) and higher in the upper GHC (~740-780°C), whereas corresponding pressure conditions at peak-T decrease from ~9-13 kbar to ~4 kbar northward. Monazite, zircon and rutile U-Pb dating results reveal two distinct blocks within the GHC of the Nyalam region. The upper GHC underwent higher degree of partial melting (15-25%, via muscovite dehydration melting) that initiated at ~32 Ma, peaked at ~29 Ma to 25 Ma, possibly ended at ~20 Ma. The lower GHC underwent lower degree of melting (0-10%) that lasted from 19 to 16 Ma, which was produced mainly via H2O-saturated melting. At different times, both the upper and lower blocks underwent initial slow cooling (35 ± 8 and 10 ± 5°C/Myr, respectively) and subsequent rapid cooling (120 ± 40°C/Myr). The established timescale of metamorphism suggests that high-temperature metamorphism within the GHC lasted a long duration (~15 Myr), whereas duration of partial melting lasted for ~3 Myr in the lower GHC and lasted for 7-12 Myr in the upper GHC. The documented diachronous metamorphism and discontinuity of peak P-T conditions implies the presence of the Nyalam Thrust in the study area. This thrust is probably connected to the other thrusts in Nepal and Sikkim Himalaya, which extends over ~800 km and is named the "High Himalayan Thrust". Timing of activity along this thrust is at ~25-16 Ma, which is coeval with active

Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina)

DEFF Research Database (Denmark)

Siegesmund, Siegfried; Steenken, A; Martino, R D

2010-01-01

The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de Córdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise...... leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon...

Rubidium-strontium chronology of the metamorphism and prehistory of central Australian granulites

Energy Technology Data Exchange (ETDEWEB)

Gray, C M [La Trobe Univ., Bundoora (Australia); Compston, W

1978-11-01

Rubidium-strontium isotopic study of intermediate-pressure granulites at Mt. Aloysius, central Australia reveals total rock isochrons that either record the metamorphism or predate it. The gneisses involved, typically quartz + feldspar + orthopyroxene + garnet granulites, occur in five lithological units which outline a simple fold structure. The distribution of isotopic ages in a 25 km/sup 2/ area is tested using 74 samples collected in groups of 2 to 4 both along and across strike in each of the units. Two total rock isochron ages of 1200 and 1550 Myr occur, and both are found at different sites in one unit. Mineral ages are younger and independent of location, with feldspars giving 800 Myr and biotites 730 Myr. The 1200 Myr isochrons show the features of outcrop-scale Sr isotopic homogenisation and are taken to record the time of metamorphism. Contemporaneous regional depletion of U, commonly associated with granulite facies metamorphism, confirms the interpretation. The 1550 Myr isochrons describe entire lithological units and are best assigned to the supracrustal genesis of the rocks. The preservation of two ages indicates that isotopic equilibration of anhydrous total rocks is incomplete even within the granulite facies. Careful interpretation is required to assign geological meaning to granulite isochrons.

Multiple tectonic mode switches indicate short-duration heat pulses in a Mio-Pliocene metamorphic core complex, West Papua, Indonesia

Science.gov (United States)

White, L. T.; Hall, R.; Gunawan, I.

2017-12-01

The Wandaman Peninsula is a narrow (2 km) promontory in remote western New Guinea. The peninsula is almost entirely composed of medium- to high-grade metamorphic rocks considered to be associated with a Mio-Pliocene metamorphic core complex. Previous work has shown that the uplift and exhumation of the core complex has potentially brought some extremely young eclogite to the surface. These might be comparable to the world's youngest (4.3 Ma) eclogites found in the D'Entrecasteaux Islands at the opposite end of New Guinea. We show that tectonic history of this region is complex. This is because the metamorphic sequences in the Wandaman Peninsula record multiple phases of deformation, all within the last few million years. This is demonstrated through methodical collation of cross-cutting relations from field and microstructural studies across the peninsula. The first phase of deformation and metamorphism is associated with crustal extension and partial melting that took place at 5-7 Ma according to new U-Pb data from metamorphic zircons. This extensional phase ceased after a tectonic mode switch and the region was shortened. This is demonstrated by two phases of folding (1. recumbent and 2. open) that overprint the earlier extensional fabrics. All previous structures were later overprinted by brittle extensional faults and uplift. This extensional phase is still taking place today, as is indicated by submerged forests exposed along the coastline associated with recent earthquakes and hot springs. The sequence of metamorphic rocks that are exposed in the Wandaman Peninsula show that stress and thermal conditions can change rapidly. If we consider that the present is a key to the past, then such results can identify the duration of deformation and metamorphic events more accurately than in much older orogenic systems.

Silicate-Oxide Equilibria in the Wilson Lake Terrane, Labrador - Evidence for a Pre- Metamorphic Oxidizing Event

Science.gov (United States)

Korhonen, F. J.; Stout, J. H.

2006-05-01

The presence of Fe3+ and Ti in silicates and their presumed equilibration with Fe2+-Fe3+-Ti oxide minerals has long been recognized as an important factor in metamorphic phase equilibria. The Red Wine Mountains massif is a granulite facies unit in the Wilson Lake terrane of central Labrador, where this equilibration is especially important for estimating both temperature and fO2 during peak metamorphism. Peak assemblages are sapphirine + quartz, and orthopyroxene + sillimanite + quartz. The coexisting oxides, which are largely responsible for the pronounced aeromagnetic high of the massif, consist of nearly pure magnetite and an exsolved titanohematite. Estimates of fO2 based on magnetite + integrated titanohematite compositions are slightly below that defined by the pure magnetite-hematite buffer. This assemblage is also responsible for the magnetic signature of metagabbro and metanorite dikes, a fact which challenges the conventional wisdom that the high Fe3+ content of the host paragneisses was inherited from a highly oxidized ferruginous shale. We suggest here that prior to granulite facies metamorphism, an oxidizing hydrothermal event either coeval or following the emplacement of mafic dikes into the paragneiss host was responsible for the highly oxidized nature of the massif as a whole. Subsequent metamorphism then produced the observed assemblages. This scenario is supported by recent U-Pb zircon and monazite ages of ca. 1626 ± 10 Ma, which indicate that both metagabbro dikes and host paragneiss were metamorphosed at the same time. Dike emplacement and the oxidizing event must have preceded 1626 Ma. The implications of this pre-metamorphic oxidizing event is that Fe3+ becomes an inherent and fixed component in the chemical system during metamorphism. Phase relationships, preliminary thermodynamic modeling, and geothermobarometric constraints indicate that peak temperatures are lower than those previously determined for Fe3+-absent systems. More appropriate

Stacking and metamorphism of continuous segments of subducted lithosphere in a high-pressure wedge: The example of Alpine Corsica (France)

Science.gov (United States)

Vitale Brovarone, Alberto; Beyssac, Olivier; Malavieille, Jacques; Molli, Giancarlo; Beltrando, Marco; Compagnoni, Roberto

2013-01-01

Alpine Corsica consists of a stack of variably metamorphosed units of continental and Tethys-derived rocks. It represents an excellent example of high-pressure (HP) orogenic belt, such as the Western Alps, exposed over a small and accessible area. Compared to the Western Alps, the geology of Alpine Corsica is poorly unraveled. During the 1970s-80s, based on either lithostratigraphic or metamorphic field observations, various classifications of the belt have been proposed, but these classifications have been rarely matched together. Furthermore, through time, the internal complexity of large domains has been progressively left aside in the frame of large-scale geodynamic reconstructions. As a consequence, major open questions on the internal structure of the belt have remained unsolved. Apart from a few local studies, Alpine Corsica has not benefited of modern developments in petrology and basin research. This feature results in several uncertainties when combining lithostratigraphic and metamorphic patterns and, consequently, in the definition of an exhaustive architecture of the belt. In this paper we provide a review on the geology of Alpine Corsica, paying particular attention to the available lithostratigraphic and metamorphic classifications of the metamorphic terranes. These data are completed by a new and exhaustive metamorphic dataset obtained by means of thermometry based on Raman Spectroscopy of Carbonaceous Material (RSCM). This technique provides reliable insights on the peak temperature of the metamorphic history for CM-bearing metasediments. A detailed metamorphic characterization of metasediments, which have been previously largely ignored due to retrogression or to the lack of diagnostic mineralogy, is thus obtained and fruitfully coupled with the available lithostratigraphic data. Nine main tectono-metamorphic units are defined, from subgreenschist (ca. 280-300 °C) to the lawsonite-eclogite-facies (ca. 500-550 °C) condition. These units are

Operating practical experience at Argentina

International Nuclear Information System (INIS)

Quihillalt, Oscar

1997-01-01

Operating experiences of Atucha-1 and Embalse Nuclear Power Plants were discussed in this work. The technical and economic aspects, such as reliability, availability, personnel training, operating costs, prices and market, which exercise influence upon Argentina nuclear energy policy, mainly on the power electric generation by nuclear power plants were considered. Finally the current status of the nucleoelectric sector in Argentina and forecasting were analysed

Boll weevil invasion process in Argentina

Science.gov (United States)

The boll weevil, Anthonomus grandis grandis Boheman, is the most destructive cotton pest in the Western Hemisphere. In 1993, the pest was reported in Argentina, and in 1994 boll weevils were captured in cotton fields in the Formosa Province on the border between Argentina and Paraguay. The pest ha...

Tectonic origin and deformation process of the Mayer Kangri medium-high pressure metamorphic dome in Central Qiangtang of Tibet

Science.gov (United States)

Wang, Y.; Liang, X.

2016-12-01

The metamorphic characteristics, deformation process, geochronology of the medium-high pressure metamorphic rocks in blueschist bearing Central Qiangtang Metamorphic belt (CQMB) of Tibet were less well constrained. It is, however, commonly assumed that these rock slices in the margin also contain important implications on the evolution of the entire metamorphic belt. The well-exposed Mayer Kangri medium-high pressure metamorphic dome in north flank of the CQMB provides an unique opportunity to investigate the outer part of the CQMB, which could facilitate the study on the subduction-exhumation-post orogenic scenarios of the Triassic accretionary orogeny in Central Qiangtang. Field structural analyses indicate the Mayer Kangri metamorphic dome are bounded by low-angle normal faults (LANF) within the hanging wall of low-green schist facies mélange. It majorly consists of epidote-amphibolites, quartz-phengite schist, epidote-albite schist. The outcrop and micro structural observations of footwall metamorphic rocks show an open anticline with multiple foliation replacement, which largely differentiate themselves from the dextral strike-slip shearing of the hanging wall. Well-zoned amphiboles were found within the epidote-amphibolite after micro-structural observations and electron probe microanalyses (EPMA), which indicate that the amphibole zonation demonstrates a Hastingsite core, a Ferro-actinolite mantle and a Ferro-winchite rim in most cases. The mean temperature and pressure estimates of the zoned amphibolites change from 544 °, 0.98Gpa in the core, to 426°, 0.34Gpa in the mantle, and to ca.364° and 0.70 GPa in the rim. The detailed analyses on the stepwise-heating Ar-Ar results of the zoned amphiboles provide good constrains on the episodic deformation process of the CQMB. For Hast-cores, we obtained near plateau ages of 242.4-241.2 Ma, indicating the onset of the oceanic subduction is earlier than the Anisian stage of Middle Triassic. The subsequent

Epitaxial nanowire formation in metamorphic GaAs/GaPAs short-period superlattices

Science.gov (United States)

Zheng, Nan; Ahrenkiel, S. Phillip

2017-07-01

Metamorphic growth presents routes to novel nanomaterials with unique properties that may be suitable for a range of applications. We discuss self-assembled, epitaxial nanowires formed during metalorganic chemical vapor deposition of metamorphic GaAs/GaPAs short-period superlattices. The heterostructures incorporate strain-engineered GaPAs compositional grades on 6°-B miscut GaAs substrates. Lateral diffusion within the SPS into vertically aligned, three-dimensional columns results in nanowires extending along A directions with a lateral period of 70-90 nm. The microstructure is probed by transmission electron microscopy to confirm the presence of coherent GaAs nanowires within GaPAs barriers. The compositional profile is inferred from analysis of {200} dark-field image contrast and lattice images.

K-Ar and Ar-Ar dating of the Palaeozoic metamorphic complex from the Mid-Bosnian Schist Mts., Central Dinarides, Bosnia and Hercegovina

International Nuclear Information System (INIS)

Pamic, J.; Balogh, K.; Hrvatovic, H.; Balen, D.; Palinkas, L.; Jurkovic, I.

2004-01-01

K-Ar and Ar-Ar whole rock and mineral ages are presented for 25 samples of metamorphic rocks from the Mid-Bosnian Schist Mts., representing one of the largest allochthonous Palaeozoic terranes incorporated within the Internal Dinarides. Four main age groups can be distinguished: 1) Variscan (∼ 343 Ma), 2) post-Variscan (288-238 Ma), 3) Early Cretaceous (mainly 121-92 Ma), and 4) Eocene (59--35 Ma) ages. Apart from this, an Oligocene (31 Ma) age was obtained on Alpine vein hyalophane. The radiometric dating indicates a polyphase metamorphic evolution of the Palaeozoic formations and suggests a pre-Carboniferous age of the volcano-sedimentary protoliths, an Early Carboniferous age of Variscan metamorphism and deformation, post-Variscan volcanism, an Early Cretaceous metamorphic overprint related to out-of-sequence thrusting of the Palaeozoic complex, and an Eocene and Oligocene metamorphic overprint related to the main Alpine compressional deformation and subsequent strike-slip faulting, and uplift of the metamorphic core. Accordingly, the Mid-Bosnian Schist Mts. can be correlated in its multistage geodynamic evolution with some Palaeozoic tectonostratigraphic units from the Austroalpine domain in the Eastern Alps. (author)

Thermochronological constraints on the Cambrian to recent geological evolution of the Argentina passive continental margin

Science.gov (United States)

Kollenz, Sebastian; Glasmacher, Ulrich A.; Rossello, Eduardo A.; Stockli, Daniel F.; Schad, Sabrina; Pereyra, Ricardo E.

2017-10-01

Passive continental margins are geo-archives that store information from the interplay of endogenous and exogenous forces related to continental rifting, post-breakup history, and climate changes. The recent South Atlantic passive continental margins (SAPCMs) in Brazil, Namibia, and South Africa are partly high-elevated margins ( 2000 m a.s.l.), and the recent N-S-trending SAPCM in Argentina and Uruguay is of low elevation. In Argentina, an exception in elevation is arising from the higher topography (> 1000 m a.s.l.) of the two NW-SE-trending mountain ranges Sierras Septentrionales and Sierras Australes. Precambrian metamorphic and intrusive rocks, and siliciclastic rocks of Ordovician to Permian age represent the geological evolution of both areas. The Sierras Australes have been deformed and metamorphosed (incipient - greenschist) during the Gondwanides Orogeny. The low-temperature thermochronological (LTT) data (history of the Gondwanides and the Mesozoic and Cenozoic South Atlantic geological evolution. Upper Carboniferous zircon (U-Th/He)-ages (ZHe) indicate the earliest cooling below 180 °C/1 Ma. Most of the ZHe-ages are of Upper Triassic to Jurassic age. The apatite fission-track ages (AFT) of Sierras Septentrionales and the eastern part of Sierras Australes indicate the South Atlantic rifting and, thereafter. AFT-ages of Middle to Upper Triassic on the western side of the Sierras Australes are in contrast, indicating a Triassic exhumation caused by the eastward thrusting along the Sauce Grande wrench. The corresponding t-T models report a complex subsidence and exhumation history with variable rates since the Ordovician. Based on the LTT-data and the numerical modelling we assume that the NW-SE-trending mountain ranges received their geographic NW-SE orientation during the syn- to post-orogenic history of the Gondwanides.

Argentina

International Nuclear Information System (INIS)

Masters, R.

1997-01-01

This article provides information on the energy resources, government, electricity supply, nuclear industry and fuel cycle of Argentina. About 12% of electric power produced is generated from nuclear power plants. The operating capacity, history and partial privatisation of the nuclear industry are covered, and fuel cycle facilities described. These include uranium mining and processing, enrichment, fuel fabrication and heavy water production. (UK)

X-ray color maps of the zoned garnets from Silgará Formation metamorphic rocks,SantanderMassif, Eastern Cordillera (Colombia

Directory of Open Access Journals (Sweden)

Takasu Akira

2010-12-01

Full Text Available

The metamorphic rocks of the Lower Paleozoic Silgará Formation of the Santander Massif, Eastern Cordillera (Colombia, were affected by a Barrovian-type metamorphism under low to high temperature and medium pressure conditions. These rocks contain garnet porphyroblasts, which show several kinds of chemical zoning patterns. The garnet grains behave as closed systems with respect to the rock matrix. Most of the observed zoning patterns are due to gradual changes in physicochemical conditions during growth. However, some garnet grains show complex zoning patterns during multiple deformation and metamorphic events.

Eclogite-high-pressure granulite metamorphism records early collision in West Gondwana: new data from the Southern Brasilia Belt, Brazil

DEFF Research Database (Denmark)

Reno II, Barry Len; Brown, Michael; Kobayashi, Katsura

2009-01-01

constrain the age of. (1) retrograded eclogite from a block along the tectonic contact beneath the uppermost nappe in a stack of passive margin-derived nappes; (2) high-pressure granulite-facies metamorphism in the uppermost passive margin-derived nappe; (3) high-pressure granulite-facies metamorphism...... in the overlying arc-derived nappe. Rare zircons from a retrograded eclogite yield a Pb-206/U-238 age of 678 +/- 29 Ma. which we interpret as most likely to (late close-to-peak-P metamorphism and to provide a minimum age for detachment of the overlying passive margin-derived nappe from the subducting plate. Zircon...

The Heart of China revisited: II Early Paleozoic (ultra)high-pressure and (ultra)high-temperature metamorphic Qinling orogenic collage

Science.gov (United States)

Bader, Thomas; Franz, Leander; Ratschbacher, Lothar; de Capitani, Christian; Webb, A. Alexander G.; Yang, Zhao; Pfänder, Jörg A.; Hofmann, Mandy; Linnemann, Ulf

2013-07-01

Orogens with multiple (ultra)high-pressure ((U)HP) and (ultra)high-temperature ((U)HT) metamorphic events provide a complex but telling record of oceanic and continental interaction. The Early Paleozoic history of the "Heart of China," the Qinling orogenic collage, offers snapshots of at least three (U)HP and two (U)HT metamorphic events. The preservation of remnants of both oceanic and continental domains together with a ≥110 Myr record of magmatism allows the reconstruction of the processes that resulted in this disparate metamorphism. Herein, we first illuminate the pressure-temperature-time (P-T-t) evolution of the Early Paleozoic (U)HP and (U)HT events by refining the petrographic descriptions and P-T estimates, assess published, and employ new U/Th-Pb zircon, monazite, and titanite, and 40Ar-39Ar phengite geochronology to date the magmatic and metamorphic events. Then we explore how the metamorphic and magmatic events are related tectonically and how they elucidate the affinities among the various complexes in the Qinling orogenic collage. We argue that a Meso-Neoproterozoic crustal fragment—the Qinling complex—localized subduction-accretion events that involved subduction, oceanic-arc formation, and back-arc spreading along its northern margin, and mtantle-wedge exhumation and spreading-ridge subduction along its southern margin.

Metamorphic Perspectives of Subduction Zone Volatiles Cycling

Science.gov (United States)

Bebout, G. E.

2008-12-01

Field study of HP/UHP metamorphic rocks provides "ground-truthing" for experimental and theoretical petrologic studies estimating extents of deep volatiles subduction, and provides information regarding devolatilization and deep subduction-zone fluid flow that can be used to reconcile estimates of subduction inputs and arc volcanic outputs for volatiles such as H2O, N, and C. Considerable attention has been paid to H2O subduction in various bulk compositions, and, based on calculated phase assemblages, it is thought that a large fraction of the initially structurally bound H2O is subducted to, and beyond, subarc regions in most modern subduction zones (Hacker, 2008, G-cubed). Field studies of HP/UHP mafic and sedimentary rocks demonstrate the impressive retention of volatiles (and fluid-mobile elements) to depths approaching those beneath arcs. At the slab-mantle interface, high-variance lithologies containing hydrous phases such as mica, amphibole, talc, and chlorite could further stabilize H2O to great depth. Trench hydration in sub-crustal parts of oceanic lithosphere could profoundly increase subduction inputs of particularly H2O, and massive flux of H2O-rich fluids from these regions into the slab-mantle interface could lead to extensive metasomatism. Consideration of sedimentary N concentrations and δ15N at ODP Site 1039 (Li and Bebout, 2005, JGR), together with estimates of the N concentration of subducting altered oceanic crust (AOC), indicates that ~42% of the N subducting beneath Nicaragua is returned in the corresponding volcanic arc (Elkins et al., 2006, GCA). Study of N in HP/UHP sedimentary and basaltic rocks indicates that much of the N initially subducted in these lithologies would be retained to depths approaching 100 km and thus available for addition to arcs. The more altered upper part of subducting oceanic crust most likely to contribute to arcs has sediment-like δ15NAir (0 to +10 per mil; Li et al., 2007, GCA), and study of HP/UHP eclogites

Diccionario del español de Argentina

OpenAIRE

Haensch, Günther

2000-01-01

Diccionario del español de Argentina : español de Argentina - español de España / Günther Haensch ; Reinhold Werner. Madrid : Gredos, 2000. - LI, 729 S. - (Diccionarios contrastivos del español de América)

Argentina

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that like so many other countries, Argentina is in the throes of privatization and restructuring of its economic programs. This has had a direct effect on the LPG industry. Argentina is a country with many natural resources. However, natural gas and crude, while present, are not in abundance. Imports of these and their associated products are needed to satisfy the growing need of the population from time to time. This is especially true with LPGs. Production of the fuel averages about 1 million tons, not enough to satisfy internal needs in the winter but enough to permit some exports in the summer to nearby Brazil. The Country's Congress approved a plan to sell-off or lease parts of the natural gas distribution network and other businesses of Gas del Estado. Subsequent new legislation has called for ten new natural gas distribution zones. Included in the sell-off is the company's propane distribution division. What is left of Gas del Estado and YPF will become a corporation in the true sense of the word. Stocks in YPF are to be sold to the public

Metamorphic Testing Integer Overflow Faults of Mission Critical Program: A Case Study

Directory of Open Access Journals (Sweden)

Zhanwei Hui

2013-01-01

Full Text Available For mission critical programs, integer overflow is one of the most dangerous faults. Different testing methods provide several effective ways to detect the defect. However, it is hard to validate the testing outputs, because the oracle of testing is not always available or too expensive to get, unless the program throws an exception obviously. In the present study, the authors conduct a case study, where the authors apply a metamorphic testing (MT method to detect the integer overflow defect and alleviate the oracle problem in testing critical program of Traffic Collision Avoidance System (TCAS. Experimental results show that, in revealing typical integer mutations, compared with traditional safety property testing method, MT with a novel symbolic metamorphic relation is more effective than the traditional method in some cases.

Mapping contact metamorphic aureoles in Extremadura, Spain, using Landsat thematic mapper images

Science.gov (United States)

Rowan, L.C.; Anton-Pacheco, C.; Brickey, D.W.; Kingston, M.J.; Payas, A.

1987-01-01

In the Extremadura region of western Spain, Ag, Pb, Zn, and Sn deposits occur in the pieces of late Hercynian granitic plutons and near the pluton contacts in late Proterozoic slate and metagraywacke that have been regionally metamorphosed to the green schist facies. The plutons generally are well exposed and have distinctive geomorphological expression and vegetation; poor exposures of the metasedimentary host rocks and extensive cultivation, however, make delineation of the contact aureoles difficult. Landsat Thematic Mapper (TM) images have been used to distinguish soil developed on the contact metamorphic rocks from soil formed on the stratigraphically equivalent slate-metagraywacke sequence. The mineral constituents of these soils are similar, except that muscovite is more common in the contact metamorphic soil; carbonaceous material is common in both soils. Contact metamorphic soil have lower reflectance, especially in the 1.6-micrometers wavelength region (TM 5), and weaker Al-OH, Mg-OH, and Fe3+ absorption features than do spectra of the slate-metagraywacke soil. The low-reflectance and subdued absorption features exhibited by the contact metamorphic soil spectra are attributed to the high absorption coefficient f the carbonaceous material caused by heating during emplacement of the granitic plutons. These spectral differences are evident in a TM 4/3, 4/5, 3/1 color-composite image. Initially, this image was used to outline the contact aureoles, but digital classification of the TM data was necessary for generating internally consistent maps of the distribution of the exposed contact metamorphic soil. In an August 1984, TM scene of the Caceras area, the plowed, vegetation-free fields were identified by their low TM 4/3 values. Then, ranges of TM 4/5 and 3/1 values were determine for selected plower fields within and outside the contact aureoles; TM 5 produced results similar to TM 4/5. Field evaluation, supported by X-ray diffraction and petrographic

Reconnaissance and economic geology of Copper Mountain metamorphic complex, Owl Creek Mountains, Wyoming

International Nuclear Information System (INIS)

Hausel, W.D.

1983-01-01

The Copper Mountain metamorphic complex lies within a westerly trending belt of Precambrian exposures known as the Owl Creek Mountains uplift. The metamorphic complex at Copper Mountain is part of a larger complex known as the Owl Creek Mountains greenstone belt. Until more detailed mapping and petrographic studies can be completed, the Copper Mountain area is best referred to as a complex, even though it has some characteristics of a greestone belt. At least three episodes of Precambrian deformation have affected the supracrustals, and two have disturbed the granites. The final Precambrian deformation event was preceded by a weak thermal event expressed by retrogressive metamorphism and restricted metasomatic alteration. During this event, a second phase of pegmatization was accompanied by hydrothermal solutions. During the Laramide orogeny, Copper Mountain was again modified by deformation. Laramide deformation produced complex gravity faults and keystone grabens. Uranium deposits were formed following major Laramide deformation. The genesis of these deposits is attributable to either the leaching of granites or the leaching of overlying tuffaceous sediments during the Tertiary. Production of metals and industrial minerals has been limited, although some gold, copper, silver, tungsten, beryl, feldspar, and lithium ore have been shipped from Copper Mountain. A large amount of uranium was produced from the Copper Mountain district in the 1950s

Isotopic chronometry of zoned garnets: Growth kinetics and metamorphic histories

International Nuclear Information System (INIS)

Vance, D.; O'Nions, R.K.

1990-01-01

Basic information on the chronological and pressure-temperature evolution of regional metamorphic terrains may in principle be derived from metamorphic garnets because of the similarly low diffusivities of Sm, Nd and major cations in this mineral. We report here Sm-Nd and Rb-Sr isotopic and major element data on prograde garnets from regionally metamorphosed pelites from Newfoundland. The garnets preserve a prograde major element zonation as well as a sympathetic variation in Sm/Nd ratio. Sm-Nd data for separated portions of the garnet from core to rim provide both upper limits on the time for garnet growth and demonstrate synchronous growth of different garnet grains on a hand specimen scale. The Rb-Sr data on the same garnet fractions are in general agreement with these results but in some cases cannot be interpreted in terms of growth. A minimum heating rate of 3 K Ma -1 is derived by combining the estimates for garnet growth time with the apparent temperature interval over which the garnet grew, deduced from the major element zonation. This value is similar to the minimum suggested by theoretical models for the thermal evolution of thickened continental crust. The growth rate is within the range of 1.3-19 mm Ma -1 , set respectively by the isotopic data and the likely upper limit for heating rate during regional metamorphism. These growth rates appear too slow to be controlled by surface reaction and suggest that other factors, such as transport, may be rate-limiting. In this case, the limits set of the effective diffusion coefficient for material transport to the growth site (=0.4-6.1x10 -17 m 2 s -1 ) suggest that grain boundary diffusion is probably the transport mechanism for supply of material to the growing garnet. (orig.)

Spatiotemporal evolution of magmatic pulses and regional metamorphism during a Cretaceous flare-up event: Constraints from the Ryoke belt (Mikawa area, central Japan)

Science.gov (United States)

Takatsuka, Kota; Kawakami, Tetsuo; Skrzypek, Etienne; Sakata, Shuhei; Obayashi, Hideyuki; Hirata, Takafumi

2018-05-01

The spatiotemporal relationship between granitoid intrusions and low-pressure/temperature type regional metamorphism in the Ryoke belt (Mikawa area) is investigated to understand the tectono-thermal evolution of the upper- to middle-crust during a Cretaceous flare-up event at the Eurasian active continental margin. Three plutono-metamorphic stages are recognized; (1) 99-84 Ma: intrusion of granitoids (99-95 Ma pulse) into the upper crust and high-T regional metamorphism reaching sillimanite-grade (97.0 ± 4.4 Ma to 88.5 ± 2.5 Ma) in the middle crust, (2) 81-75 Ma: intrusion of gneissose granitoids (81-75 Ma Ma pulse) into the middle crust at 19-24 km depth, and (3) 75-69 Ma: voluminous intrusions of massive to weakly-foliated granitoids (75-69 Ma pulse) at 9-13 km depth and formation of contact metamorphic aureoles. Cooling of the highest-grade metamorphic zone below the wet solidus of granitic rocks is estimated at 88.5 ± 2.5 Ma. At ca. 75 Ma, the upper-middle crustal section underwent northward tilting, resulting in the exhumation of regional metamorphic zones to 9-13 km depth. Although the highest-grade metamorphic rocks and the 99-95 Ma pulse granitoids preserve similar U-Pb zircon ages, the absence of spatial association suggests that the regional metamorphic zones were mainly produced by a transient thermal anomaly in the mantle and thermal conduction through the crust, supplemented by localized advection due to granitoid intrusions. The successive emplacement of granitoids into shallow, deep and shallow levels of the crust was probably controlled by the combination of change in thermal structure of the crust and tectonics during granitoid intrusions.

Metamorfismo de baja presión, su relación con el desarrollo de la Cuenca Puncoviscana, plutonismo y régimen tectónico. Argentina

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Durand, F. R.

1992-12-01

Full Text Available In the Cordillera Oriental Argentina (22 and 26° S, the Puncoviscana Formation Basin was developed, in which an extensional tectonic setting would had been supported from Upper Precambrian to Middle Ordovician. That is suggested by the limited crustal thickening, the insignificant uplift after deformation, the sedimentary-synchronous basic-alkalic lavas and the growth of a low-pressure high-temperature metamorphism that culminates in anatectic migmatites, which have no explanation by the only magmatic heat derived from the little trondhjemite-granodiorite diapires intruded during the Middle Ordovician.En la Cordillera Oriental Argentina (22 y 26° S, se desarrolló la cuenca de la Formación Puncoviscana, en la que predominó un régimen tectónico de extensión cortical, que se habría mantenido desde el Precámbrico Superior hasta el Ordovícico Medio, sugerido por el escaso engrosamiento cortical, el insignificante ascenso después de la deformación y las capas de lavas básicas alcalinas intercaladas. El desarrollo de un metamorfismo de baja presión y alta temperatura culmina en migmatitas anatécticas, que no pueden explicarse por la sola acción del calor magmático derivado de los pequeños diapiros trondhjemíticos y granodioríticos, intruidos durante el Ordovícico Medio.

Late-Paleozoic-Mesozoic deformational and deformation related metamorphic structures of Kuznetsk-Altai region

Science.gov (United States)

Zinoviev, Sergei

2014-05-01

Kuznetsk-Altai region is a part of the Central Asian Orogenic Belt. The nature and formation mechanisms of the observed structure of Kuznetsk-Altai region are interpreted by the author as the consequence of convergence of Tuva-Mongolian and Junggar lithospheric block structures and energy of collision interaction between the blocks of crust in Late-Paleozoic-Mesozoic period. Tectonic zoning of Kuznetsk-Altai region is based on the principle of adequate description of geological medium (without methods of 'primary' state recovery). The initial indication of this convergence is the crust thickening in the zone of collision. On the surface the mechanisms of lateral compression form a regional elevation; with this elevation growth the 'mountain roots' start growing. With an approach of blocks an interblock elevation is divided into various fragments, and these fragments interact in the manner of collision. The physical expression of collision mechanisms are periodic pulses of seismic activity. The main tectonic consequence of the block convergence and collision of interblock units is formation of an ensemble of regional structures of the deformation type on the basis of previous 'pre-collision' geological substratum [Chikov et al., 2012]. This ensemble includes: 1) allochthonous and autochthonous blocks of weakly deformed substratum; 2) folded (folded-thrust) systems; 3) dynamic metamorphism zones of regional shears and main faults. Characteristic of the main structures includes: the position of sedimentary, magmatic and PT-metamorphic rocks, the degree of rock dynamometamorphism and variety rock body deformation, as well as the styles and concentrations of mechanic deformations. 1) block terranes have weakly elongated or isometric shape in plane, and they are the systems of block structures of pre-collision substratum separated by the younger zones of interblock deformations. They stand out among the main deformation systems, and the smallest are included into the

The health crisis in Argentina.

Science.gov (United States)

Escudero, José Carlos

2003-01-01

The health crisis in Argentina is part of the larger crisis that has resulted from a collapse in the country's economic and political systems. After a brief review of the country's history over the last century, from international success story to economic failure, the author explains the health crisis in particular and the social crisis in general in terms of failed neoliberal policies imposed on Argentina by the United States and International Monetary Fund through the mediation of the country's political class.

Novedades en la Distribución de las Cyatheaceae (Pteridophyta en Argentina Novelties in the distribution of Cyatheaceae (Pteridophyta of Argentina

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Gonzalo J. Marquez

2006-12-01

Full Text Available Cyathea atrovirens (Langsd. & Fisch. Domin se cita por primera vez para la provincia de Corrientes (Argentina. De esta manera se extiende su área de distribución hacia el sudoeste. Además se confirma la presencia de Alsophila odonelliana (Alston M. Lehnert en la provincia de Jujuy (Argentina. En este estudio los caracteres de las esporas resultaron diagnósticos para la determinación genérica de los taxa.Cyathea atrovirens (Langsd. & Fisch. Domin is reported for the first time for Corrientes province (Argentina. Thus, its area of distribution is extended southwest. The presence of Alsophila odonelliana (Alston M. Lehnert is confirmed for Jujuy province (Argentina. In this study the spore features were diagnostic in order to determine these taxa.

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

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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.

The tectonic significance of K/Ar illite fine-fraction ages from the San Luis Formation (Eastern Sierras Pampeanas, Argentina)

Science.gov (United States)

Wemmer, Klaus; Steenken, André; Müller, Stefan; de Luchi, Mónica G. López; Siegesmund, Siegfried

2011-04-01

The Sierra de San Luis forms the southern tip of the Eastern Sierras Pampeanas in central Argentina. Two narrow belts of low-grade phyllites and quartz arenites, i.e. the San Luis Formation, have accommodated part of the strain-related differential exhumation of the medium- to high-grade metamorphic domains that constitute to the basement complex of the sierra. Eleven phyllite samples were subjected to the K/Ar fine-fraction dating technique. Results are interpreted in relation to the Kübler index of the illites, which indicate epimetamorphic conditions for the majority of the samples. Obtained ages between 330 and 290 Ma cover a period of compressional tectonics in the late Mississippian (Visean/Serpukhovian boundary) followed by the subsidence during the formation of the Paganzo Basin in the provinces of La Rioja and San Luis. These tectonic movements are coincident with the Toco orogeny in northern Chile and southern Bolivia. This suggests that the older K/Ar ages document the compressional stage and that younger ages record the cooling of the basement during the subsequent extensional uplift of the basement.

de la sociedad argentina

Directory of Open Access Journals (Sweden)

Diego Galeano

2007-01-01

Full Text Available Este artículo trata sobre un período de la historia argentina en el cual la "mirada médica", a través de un grupo de prestigiosos intelectuales, se convirtió en una clave de interpretación de la sociedad argentina. El análisis gira en torno a la obra de uno de los médicos higienistas más influyentes, José María Ramos Mejía, deteniéndose especialmente en su libro más famoso: Las multitudes argentinas (1899. La hipótesis principal que recorre el texto es la siguiente: la medicalización de la sociedad, acentuada luego de las epidemias de cólera y fiebre amarilla de mediados del siglo XIX, ofreció a las elites públicas la posibilidad de construir dominios legítimos de intervención estatal. Intromisiones del Estado en la vida privada que, además de ser algo resistidas por la población, entraban en tensión con los principios teóricos del liberalismo que los propios miembros de la elite defendían.

Argentina

Energy Technology Data Exchange (ETDEWEB)

1999-09-01

This report presents a brief overview of the socio-economic, energy and environmental context in which climate change mitigation actions in Argentina shall be inserted. To that end, the dynamic of the Argentine economic development, its influence on the energy system and environmental impacts is summarised. From the environmental standpoint, emphasis shall only be made on the impact of economic development patterns and energy policies on GHG emission. (au) 73 refs.

High-pressure granulites in the Fuping Complex of the central North China Craton: Metamorphic P-T-t evolution and tectonic implications

Science.gov (United States)

Qian, Jiahui; Yin, Changqing; Zhang, Jian; Ma, Li; Wang, Luojuan

2018-04-01

Mafic granulites in the Fuping Complex occur as lenses or boudins within high-grade TTG (Trondhjemite-Tonalite-Granodiorite) gneisses. Petrographic observations reveal four generations of mineral assemblage in the granulites: an inclusion assemblage of hornblende + plagioclase + ilmenite + quartz within garnet core; an inferred peak assemblage composed of garnet ± hornblende + plagioclase + clinopyroxene + rutile/ilmenite + quartz; a decompression assemblage characterized by symplectites of clinopyroxene ± orthopyroxene + plagioclase, coronae of plagioclase ± clinopyroxene ± hornblende around embayed garnet porphyroblasts or a two-pyroxene association; and a late amphibolite-facies retrogressive assemblage. Two representative samples were used for pseudosection modeling in NCFMASHTO model system to determine their metamorphic evolution. The results show that these granulites experienced a high-pressure stage of metamorphism with peak P-T conditions of 12-13 kbar and 760-800 °C (Pmax) and a post-peak history under P-T conditions of ∼9.0 kbar and 805-835 °C (Tmax), indicating a nearly isothermal decompression process (ITD) with a slight heating. Metamorphic evolution from the Pmax to the Tmax is predicted to be dominated by garnet breakdown through continuous metamorphic reactions of garnet + quartz ± diopside = hornblende + plagioclase + liquid and garnet + quartz + hornblende = plagioclase + diopside + liquid + orthopyroxene. Further metamorphic evolution after the Tmax is dominated by cooling, suggesting that high-pressure (HP) granulites may also exist in the Fuping Complex. Metamorphic zircons in the Fuping HP mafic granulites have left inclined REE patterns, Ti contents of 1.68-6.88 ppm and crystallization temperatures of 602-712 °C. SIMS zircon U-Pb dating on these zircons yields 207Pb/206Pb ages of 1891 ± 14 Ma and 1849 ± 6 Ma, interpreted to represent the cooling stage of metamorphism. The P-T-t evolution of the Fuping HP mafic granulites records

Study on Kalimantan uranium province: The assessment on uranium mineralization of metamorphic and granitic rocks at Schwaner mountains

International Nuclear Information System (INIS)

Tjokrokardono, Soeprapto

2002-01-01

Uranium exploration activities done by CEA-BATAN had discovered uranium occurrences as the radiometric and uranium content anomalies at metamorphic and granite rocks of Schwaner Mountains, Kalimantan. A part of the occurrences on metamorphic rocks at Kalan basin has been evaluated and be developed onto follow-up step of prospecting by construction of some drilling holes and an exploration adit. In order to increase the national uranium resources, it is necessarily to extent the exploration activity to out side or nearby of Kalan basin. The goal of this assessment is to understand the uranium accumulation mechanism at Pinoh metamorphic rocks of Kalan Kalimantan and to delineate areas that uranium may exist. The assessment was based on the aspect of geology, anomaly of radioactivity and uranium contents, tectonics and alterations. Pinoh metamorphic rocks which is influenced by Sukadana granite intrusion are the high potential rocks for the uranium accumulation, because the intrusion contains a relatively high of U, Th, Cu, Zn, Nb, Mn, and W. The potential rock distributions are in between G. Ransa granite intrusion at the east and Kotabaru granite intrusions at the west. The mineralizations are categorized as vein type deposits of granitic association

Crisis cambiaria en Argentina

OpenAIRE

Féliz, Mariano

2009-01-01

El análisis de la articulación entre el proceso de valorización exitosa de capital y la tendencia a la desvalorización de las mercancías se aplica a una de las manifestaciones de la crisis argentina: la devaluación del peso. Se estudia la relación entre la determinación del tipo de cambio y la valorización del capital. Se discuten las tendencias concretas de la economía argentina en la década de 1990 y se muestra cómo la devaluación de 2001-2002 fue producto necesario del propio proceso de va...

Assessment of fire-damaged concrete. Combining metamorphic petrology and concrete petrography

NARCIS (Netherlands)

Larbi, J.A.; Nijland, T.G.

2001-01-01

Metamorphic petrology is a branch of geology that deals with the study of changes in rocks due changing physio-chemical conditions. As conditions shift in or out of the thermodynamic stability field of phases, new phases may appear whereas others disappear. A basic approach is mapping of so-called

Control of nuclear materials and materials in Argentina

International Nuclear Information System (INIS)

Arbor G, A.; Fernandes M, S.

1988-01-01

A general view about the safeguards activities in Argentina is presented. The national system of accounting for and control of nuclear materials is described. The safeguards agreement signed by Argentina are presented. (E.G.) [pt

Low temperature thermochronology and topographic evolution of the South Atlantic passive continental margin in the region in eastern Argentina

Science.gov (United States)

Pfister, Sabrina; Kollenz, Sebastian; Glasmacher, Ulrich A.

2014-05-01

To understand the evolution of the passive continental margin in Argentina low temperature thermochronology is an appropriate method, which will lead to new conclusions in this area. The Tandilia System, also called Sierras Septentrionales, is located south of the Río de la Plato Craton in eastern Argentina in the state of Buenos Aires. North of the hills Salado basin is located whereas the Claromecó basin is situated south of the mountain range. In contrary to most basins along the southamerican passive continental margin the Tandilia-System and the neighbouring basins trend perpendicular to the coast line. The topography is fairly flat with altitudes of. The igneous-metamorphic basement is pre-proterozoic in age and build up of mainly granitic-tonalitic gneisses, migmatites, amphibolites, some ultramafic rocks and granitoid plutons it is overlain by a series of Neoproterozoic to early Paleozoic sediments (Cingolani, 2010), like siliciclastics, dolostones, shales and limestones (Demoulin et al., 2005). The aim of the study is to quantify the long-term landscape evolution of the passive continental margin in eastern Argentina in terms of thermal history, exhumation and tectonic activities. For that purpose, samples were taken from the Sierra Septentrionales and analyzed with the apatite fission-track method. Further 2-D thermokinematic modeling was conducted with the computer code HeFTy (Ketcham, 2005; Ketcham 2007; Ketcham et al., 2009). The results indicate apatite fission track ages between 101.6 (9.4) to 228.9 (22.3) Ma, what means all measured ages are younger as their formation age. That shows all samples have been reset. Six samples accomplished enough confined tracks and were used to test geological t-T models against the AFT data set. These models give a more detailed insight on the cooling history and tectonic activities in the research area. References: Cingolani C. A. (2010): The Tandilia System of Argentina as a southern extension of the Río de la

Argon and fission track dating of Alpine metamorphism and basement exhumation in the Sopron Mts. (Eastern Alps, Hungary): thermochronology or mineral growth?

International Nuclear Information System (INIS)

Balogh, K.; Dunkl, I.

2005-01-01

The crystalline basement rocks of the Sopron Mountains are the easternmost and most isolated outcrops of the Austroalpine basement of the Eastern Alps. Ar/Ar and K/Ar dating of phengitic mica indicates that the Eoalpine high-pressure metamorphism of the area occurred between 76 and 71 Ma. Short-lived metamorphism is characterized by fluid-poor conditions. Fluid circulation was mostly restricted to shear zones, thus the degree of Alpine overprint has an extreme spatial variation. In several metamorphic slices Variscan mineral assemblages have been preserved and biotite yielded Variscan and Permo-Triassic Ar ages. Different mineral and isotope thermometers (literature data) yielded temperatures of 500-600 o C for the peak of Alpine metamorphism in the Sopron Mountains, but muscovite and biotite do not show complete argon resetting. Thus, we consider this crystalline area as a well constrained natural test site, which either indicates considerably high closure temperatures (around 550 o C) for Ar in muscovite and biotite in a dry metamorphic environment, or which is suitable for testing the widely applied methods of temperature estimations under disequilibrium conditions. Apatite fission track results and their thermal modeling, together with structural, mineralogical and sedimentological observations, allows the identification of a post-metamorphic, Eocene hydrothermal event and Late Miocene-Pliocene sediment burial of the crystalline rocks of the Sopron Mountains. (author)

Argentina to fully privatize state owned YPF

International Nuclear Information System (INIS)

Anon.

1992-01-01

Argentina's Congress has voted to fully privatize state petroleum company Yacimientos Petroliferos Fiscales (YPF), a move the government expects to net at least $8 billion. Despite some political opposition, the vote was 119-10 in favor, with one abstention and opposition party members refusing to participate in the vote. Argentina's President Carlos Menem had threatened to authorize YPF privatization by decree if there was no quorum for a vote. YPF is responsible for 40% of Argentina's oil production. The country h as been self-sufficient in crude since 1982. Current production is 563,472 b/d, and proved reserves of oil and gas are valued at $7 billion

First report of garnet corundum rocks from southern India: Implications for prograde high-pressure (eclogite-facies?) metamorphism

Science.gov (United States)

Shimpo, Makoto; Tsunogae, Toshiaki; Santosh, M.

2006-02-01

We report here for the first time the occurrence of garnet and corundum in Mg-Al-rich rocks at Sevitturangampatti (Namakkal district) in the Palghat-Cauvery Shear Zone System (PCSS), southern India. The rocks contain several rare mineral assemblages such as garnet-corundum-sillimanite-cordierite-sapphirine-spinel-Mg-rich staurolite, garnet-corundum-sodic gedrite-cordierite-sillimanite/kyanite, garnet-Mg-rich staurolite-sillimanite/kyanite, sodic gedrite-Mg-rich staurolite-corundum-sapphirine, biotite-corundum-sapphirine and sodic gedrite-sapphirine-spinel-cordierite. Both garnet and corundum in these rocks occur as coarse-grained (1 mm to 10 cm) porphyroblasts in the matrix of sillimanite, cordierite and gedrite. Kyanite is common as inclusions in garnet, but matrix aluminosilicates are mainly sillimanite. The presence of rare garnet + corundum, which has so far been reported from kimberlite xenoliths, aluminous eclogites and ultrahigh-pressure metamorphic rocks as well as in high-pressure experiments, suggests that the assemblage is an indicator of an unusually high-pressure event, which has not been recorded in previous studies from southern India. Phase analysis of quartz-absent MAS system also suggests high-pressure stability of the assemblage. The inference of high pressure metamorphism is also supported by the presence of Mg-rich [Mg/(Fe + Mg) = 0.51] staurolite, which has been reported from high-pressure rocks, included from cores of coarse-grained garnet and gedrite. Porphyroblastic occurrence of garnet + corundum as well as staurolite and kyanite inclusions suggests that the area underwent prograde high-pressure metamorphism, probably in the eclogite field. The rocks subsequently underwent continuous heating at 940 to 990 °C, suggesting ultrahigh-temperature (UHT) metamorphism along a clockwise trajectory. Sapphirine + cordierite and spinel + cordierite symplectites between garnet and sillimanite suggest near isothermal decompression after the peak event

Fluid-driven metamorphism of the continental crust governed by nanoscale fluid flow

NARCIS (Netherlands)

Plümper, O.; Botan, Alexandru; Los, Catharina; Liu, Yang; Malthe-Sorenssen, Anders; Jamtveit, Bjørn

2017-01-01

The transport of fluids through the Earth’s crust controls the redistribution of elements to form mineral and hydrocarbon deposits, the release and sequestration of greenhouse gases, and facilitates metamorphic reactions that influence lithospheric rheology. In permeable systems with a

Argentina; Argentine

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-04-01

This economical study summarizes the energy situation of Argentina: energy institutions and policy, energy companies (oil, electricity, gas, coal), energy supplies (resources, power production, petroleum, natural gas), prices and tariffs, consumption, economical stakes and perspectives (investments, agreements, projects). Energy data for the 1971-1999 period are summarized in graphs and tables. (J.S.)

Post-Metamorphic Thermal Anomaly across the Nacimiento Block, Central California: a Hydrothermal Overprint?

Science.gov (United States)

Lacroix, B.; Hughes, J.; Lahfid, A.; Delchini, S.

2017-12-01

The thermal history of the Nacimiento block located within the Franciscan Complex (California, USA) has been previously proposed based on both vitrinite reflectance (Rm) and illite cristallinity methods (Underwood et al., 1995). These authors suggest that the Nacimiento block is locally perturbed by a thermal anomaly (up to 300ºC), probably caused by post-metamorphic hydrothermal activity linked to the emplacement of an Au-deposit: the Los Burros Gold deposit. Although both thermal anomaly and deposit seem spatially correlated, their relationship is still poorly constrained. Detailed geological and structural mapping within the Los Burros Mining District (LBMD) coupled with a thermal study was conducted to better understand processes responsible for the anomalous temperatures recorded near the deposit. The regional maximum temperature reached by metasediments from the Nacimiento block have been first investigated using the Raman Spectroscopy of Carbonaceous Materials (RSCM) method. In addition, through careful fluid-inclusion and stable isotopes (O and C) studies on the deposit, the temperature and the potential source of the fluid responsible for the Los Burros Au-deposit emplacement were investigated. RSCM technique confirms the presence of a thermal anomaly in the range 260-320ºC near LBMD. However, our structural and petrographic results suggest that the thermal anomaly is not correlated to a post-metamorphic hydrothermal overprint but rather to a late, transpressive deformation uplifting buried metamorphic rocks.

Fore arc tectonothermal evolution of the El Oro metamorphic province (Ecuador) during the Mesozoic

Science.gov (United States)

Riel, Nicolas; Martelat, Jean-Emmanuel; Guillot, Stéphane; Jaillard, Etienne; Monié, Patrick; Yuquilema, Jonatan; Duclaux, Guillaume; Mercier, Jonathan

2014-10-01

The El Oro metamorphic province of SW Ecuador is a composite massif made of juxtaposed terranes of both continental and oceanic affinity that has been located in a fore-arc position since Late Paleozoic times. Various geochemical, geochronological, and metamorphic studies have been undertaken on the El Oro metamorphic province, providing an understanding of the origin and age of the distinct units. However, the internal structures and geodynamic evolution of this area remain poorly understood. Our structural analysis and thermal modeling in the El Oro metamorphic province show that this fore-arc zone underwent four main geological events. (1) During Triassic times (230-225 Ma), the emplacement of the Piedras gabbroic unit at crustal-root level ( 9 kbar) triggered partial melting of the metasedimentary sequence under an E-W extensional regime at pressure-temperature conditions ranging from 4.5 to 8.5 kbar and from 650 to 900°C for the migmatitic unit. (2) At 226 Ma, the tectonic underplating of the Arenillas-Panupalí oceanic unit (9 kbar and 300°C) thermally sealed the fore-arc region. (3) Around the Jurassic-Cretaceous boundary, the shift from trench-normal to trench-parallel subduction triggered the exhumation and underplating of the high-pressure, oceanic Raspas Ophiolitic Complex (18 kbar and 600°C) beneath the El Oro Group (130-120 Ma). This was followed by the opening of a NE-SW pull-apart basin, which tilted the massif along an E-W subhorizontal axis (110 Ma). (4) In Late Cretaceous times, an N-S compressional event generated heterogeneous deformation due to the presence of the Cretaceous Celica volcanic arc, which acted as a buttress and predominantly affected the central and eastern part of the massif.

Design and accuracy analysis of a metamorphic CNC flame cutting machine for ship manufacturing

Science.gov (United States)

Hu, Shenghai; Zhang, Manhui; Zhang, Baoping; Chen, Xi; Yu, Wei

2016-09-01

The current research of processing large size fabrication holes on complex spatial curved surface mainly focuses on the CNC flame cutting machines design for ship hull of ship manufacturing. However, the existing machines cannot meet the continuous cutting requirements with variable pass conditions through their fixed configuration, and cannot realize high-precision processing as the accuracy theory is not studied adequately. This paper deals with structure design and accuracy prediction technology of novel machine tools for solving the problem of continuous and high-precision cutting. The needed variable trajectory and variable pose kinematic characteristics of non-contact cutting tool are figured out and a metamorphic CNC flame cutting machine designed through metamorphic principle is presented. To analyze kinematic accuracy of the machine, models of joint clearances, manufacturing tolerances and errors in the input variables and error models considering the combined effects are derived based on screw theory after establishing ideal kinematic models. Numerical simulations, processing experiment and trajectory tracking experiment are conducted relative to an eccentric hole with bevels on cylindrical surface respectively. The results of cutting pass contour and kinematic error interval which the position error is from-0.975 mm to +0.628 mm and orientation error is from-0.01 rad to +0.01 rad indicate that the developed machine can complete cutting process continuously and effectively, and the established kinematic error models are effective although the interval is within a `large' range. It also shows the matching property between metamorphic principle and variable working tasks, and the mapping correlation between original designing parameters and kinematic errors of machines. This research develops a metamorphic CNC flame cutting machine and establishes kinematic error models for accuracy analysis of machine tools.

Metamorphism and plutonism around the middle and south forks of the Feather River, California

Science.gov (United States)

Hietanen, Anna Martta

1976-01-01

The area around the Middle and South Forks of the Feather River provides information on metamorphic and igneous processes that bear on the origin of andesitic and granitic magmas in general and on the variation of their potassium content in particular. In the north, the area joins the Pulga and Bucks Lake quadrangles studied previously. Tectonically, this area is situated in the southern part of an arcuate segment of the Nevadan orogenic belt in the northwestern Sierra Nevada. The oldest rocks are metamorphosed calcalkaline island-arc-type andesite, dacite, and sodarhyolite with interbedded tuff layers (the Franklin Canyon Formation), all probably correlative with Devonian rocks in the Klamath Mountains. Younger rocks form a sequence of volcanic, volcaniclastic, and sedimentary rocks including some limestone (The Horseshoe Bend Formation), probably Permian in age. All the volcanic and sedimentary rocks were folded and recrystallized to the greenschist facies during the Nevadan (Jurassic) orogeny and were invaded by monzotonalitic magmas shortly thereafter. A second lineation and metamorphism to the epidote-amphibolite facies developed in a narrow zone around the plutons. In light of the concept of plate tectonics, it is suggested that the early (Devonian?) island-arc-type andesite, dacite, and sodarhyolite (the Franklin Canyon Formation) were derived from the mantle above a Benioff zone by partial melting of peridotite in hydrous conditions. The water was probably derived from an oceanic plate descending to the mantle. Later (Permian?) magmas were mainly basaltic; some discontinuous layers of potassium-rich rhyolite indicate a change into anhydrous conditions and a deeper level of magma generation. The plutonic magmas that invaded the metamorphic rocks at the end of the Jurassic may contain material from the mantle, the subducted oceanic lithosphere, and the downfolded metamorphic rocks. The ratio of partial melts from these three sources may have changed with time

Measurements of atmospheric fallout in Argentina; Determinacion del fallout atmosferico en la Republica Argentina

Energy Technology Data Exchange (ETDEWEB)

Canoba, A C; Lopez, F O; Bruno, H A

1998-11-01

With the purpose of studying the radioactive fallout present in Argentina from atmospheric nuclear explosions tests that have been conducted recently, an environmental monitoring program, outside the influence of nuclear facilities of Argentina, was undertaken during 1996 and 1997. The levels of Cs-137 and Sr-90 were analysed in samples of air, deposited material (rainwater), milk, an average meal of a standard man and food. During this period, a total of 630 radiochemical analysis were performed on 325 samples of the different matrices described. The concentration levels of the radionuclides analysed in the different environmental matrices are presented and are compared with the values obtained in the environmental monitoring program done during the period 1960-1981. (author) 3 refs., 9 tabs. [Espanol] Con el proposito de estudiar la precipitacion radiactiva presente en la Republica Argentina, debido al ensayo de armas nucleares en la atmosfera realizadas en el pasado, se implemento el muestreo ambiental fuera de la zona de influencia de las instalaciones nucleares de la Argentina durante los anios 1996 y 1997. Se determinaron las concentraciones de cesio 137 y estroncio 90 en muestras de aire, deposito de material radiactivo (agua de lluvia), leche, dieta promedio de un individuo estandar y en alimentos varios. Se realizaron, durante el periodo mencionado, un total de 630 determinaciones radioquimicas sobre 325 muestras de las diferentes matrices mencionadas. Se presentan los niveles de concentracion de los radionucleidos analizados en las distintas matrices ambientales y se comparan los valores obtenidos en los monitoreos realizados durante el periodo 1960-1981. (autor)

The Metamorphic Rocks-Hosted Gold Mineralization At Rumbia Mountains Prospect Area In The Southeastern Arm of Sulawesi Island, Indonesia

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Hasria Hasria

2017-09-01

Full Text Available Recently, in Indonesia gold exploration activities  are not only focused along volcanic-magmatic belts, but also starting to shift along metamorphic and sedimentary terrains. The study area is located in Rumbia mountains, Bombana Regency, Southeast Sulawesi Province. This paper is aimed to describe characteristics of alteration and ore mineralization associated  with metamorphic rock-related gold deposits.  The study area is found the placer and  primary gold hosted by metamorphic rocks. The gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC. These quartz veins are currently recognized in metamorphic rocks at Rumbia Mountains. The quartz veins are mostly sheared/deformed, brecciated, irregular vein, segmented and  relatively massive and crystalline texture with thickness from 1 cm to 15.7 cm. The wallrock are generally weakly altered. Hydrothermal alteration types include sericitization, argillic, inner propylitic, propylitic, carbonization and carbonatization. There some precious metal identified consist of native gold and ore mineralization including pyrite (FeS2, chalcopyrite (CuFeS2, hematite (Fe2O3, cinnabar (HgS, stibnite (Sb2S3 and goethite (FeHO2. The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18.4 ppm. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposit type. The orogenic gold deposit is one of the new targets for exploration in Indonesia

The age of the rocks and the metamorphic episodes from the Southeastern of Sao Paulo state

International Nuclear Information System (INIS)

Tassinari, C.C.G.; Kawashita, K.; Schmuss, R. van; Taylor, P.N.

1988-01-01

Rb-Sr, Pb-Pb and U-Pb geochronologic studies carried out on precambrian rocks from the southeastern Sao Paulo state suggest a Complex geologic evolution during the Archean and Proterozoic times. This region is divided in five differents allochthonous terranes named Itapira-Amparo, Piracaiba-Jundiai, Sao Roque, Embu and Costeiro, separated by thrust and strike-slip faults. The Itapira-Amparo domain has a original history dating back to 3.4 Ga. and since 2.6 to 2.5 Ga. and 2.2 to 1.9 Ga. metamorphic rockformation episode occurred involving both mantle-derived magmas and recycled material. Supracrustal sequences developed around 1.4 Ga. The domain was locally reworked in 0.8 - 0.65 Ga. In the Piracaia-Jundiai the main rock-formation event occurred at 1.4 Ga., but this domian was affected by strong granization and migmatization episodes during the period 1.1 - 0.6 Ga. The third terrain is characterized by the Sao Roque metavolcanossedimentary sequence developed during the time period 1.8 - 0.7 Ga., and comprising two metamorphic superimposed events (1.4 and 0.8 - 0.7 Ga.). the post-tectonics granites ranging in ages from 0.7 to 0.55 Ga. Within the Embu terrain ages of 2.5, 1.4 and 0,75 Ga. were obtained for the metamorphic terrain, with post-tectonic activities around 650 Ma. In the Costeiro domain all the metamorphic rocks developed in late-Proterozoic time, with syntectonic phase around 650 Ma [pt

Assessment of role of metamorphic remobilization in genesis of uranium ores from Ralston Buttes area, Colorado

International Nuclear Information System (INIS)

Chatterjee, S.K.

1984-01-01

The Ralston Buttes mining district, the principal source of commercial uranium in the Front Range since the late 1940s, is located northeast of Golden and southeast of the Front Range mineral belt. Uranium ore occurs in veins emplaced in fault breccia in Precambrian metamorphic rocks. The progenitors of the metamorphic rocks are a possible source for the uranium. Hornblende gneisses of the Idaho Springs Formation is the major rock type in the area, thus its origin is a major consideration in assessing the quantity of uranium that might have been contributed by metamorphic processes. To evaluate this, 41 rock samples (19 hornblende gneisses, 7 biotite gneisses, 5 chlorite gneisses, and 10 metapelites) were analyzed for major elements, and 3 rock samples (16 hornblende gneisses, 8 biotite gneisses, 4 chlorite gneisses, and 5 mica schists) were analyzed for trace metals (Rb, Sc, Zr, V, Ni, Co, Cr, Ba, U, and Th). Four samples of hornblende gneiss and 1 sample of mica schists were also analyzed for rare earth elements. Major elements are rare earth data indicate that the hornblende gneiss was derived from sediments and tholeiitic basalts. Trace element data suggest a volcanic provenance for these sediments. Rare earth patterns and uranium and thorium abundances of metapelites are similar to average North American shales. Low uranium and thorium values and low thorium-uranium ratios in hornblende gneisses and mica schists preclude large-scale uranium remobilization during metamorphism of these source rocks

Inheritance, Variscan tectonometamorphic evolution and Permian to Mesozoic rejuvenations in the metamorphic basement complexes of the Romanian Carpathians revealed by monazite microprobe geochronology

Science.gov (United States)

Săbău, Gavril; Negulescu, Elena

2014-05-01

Monazite U-Th-Pb chemical dating reaches an acceptable compromise between precision and accuracy on one side, and spatial resolution and textural constraints on the other side. Thus it has a powerful potential in testing the coherence of individual metamorphic basement units, and enabling correlations among them. Yet, sensitivity and specificity issues in monazite response to thermotectonic events, especially in the case of superposed effects, remain still unclear. Monazite dating at informative to detailed scale in the main metamorphic basement units of the Carpathians resulted in complex age spectra. In the main, the spectra are dominated by the most pervasive thermal and structural overprint, as checked against independent geochronological data. Post-peak age resetting is mostly present, but statistically subordinate. Resetting in case of superposed events is correlated with the degree of textural and paragenetic overprinting, inheritances being always indicated by more or less well-defined age clusters. The lack of relict ages correlating with prograde structural and porphyroblast zonation patterns is indicative for juvenile formations. Age data distribution in the Carpathians allowed distinction of pre-Variscan events, syn-metamorphic Variscan tectonic stacking of juvenile and reworked basement, post-Variscan differential tectonic uplift, as well as prograde metamorphic units ranging down to Upper Cretaceous ages. In the South Carpathians, the Alpine Danubian domain consists of several Variscan and Alpine thrust sheets containing a metamorphic complex dominated by Upper Proterozoic to Lower Cambrian metamorphic and magmatic ages (Lainici-Păiuş), and several complexes with metamorphic overprints ranging from Carboniferous to Lower Permian. Any correlation among these units, as well as geotectonic models placing a Lower Paleozoic oceanic domain between pre-existing Lainici-Păiuş and Drăgşan terranes are precluded by the age data. Other basement of the

The regulatory control of radioactive sources in Argentina

International Nuclear Information System (INIS)

Rojkind, Roberto Hector

1997-01-01

Argentina has been conducting nuclear activities for more than forty years, and as early as in 1956 established a Regulatory Authority. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations had been set in Argentina, before the accident in Goiania. The conclusions drawn from that accident encouraged in Argentina the improvement of some regulatory procedures and helped to enhance the quality of the regulatory process. Therefore, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain improved. Some lessons learned in Argentina from the accident in Goiania and the main characteristics of an effective enforcement program helpful to prevent radiological accidents in industrial, medical, research and teaching uses of radioactive sources are presented. (author)

Uranium deposit types and resources of Argentina

International Nuclear Information System (INIS)

Lopez, L.; Cuney, M.

2014-01-01

The uranium-related activities in Argentina begun in the 1950s and, as a result of the systematic exploration, several types of deposits have been discovered since then: volcanic and caldera-related, sandstone-hosted, vein spatially related to granite (intragranitic and perigranitic) and surficial. The deposits that have been the focus of the most important uranium exploitations are the ones that belong to the volcaniclastic type. These are localized in Permian formations associated with synsedimentary acid volcanism in the Sierra Pintada district (Mendoza province). The volcanic and caldera related type is also present in the Laguna Colorada deposit (Chubut province) located in the San Jorge basin (Cretaceous). Several important uranium mineralisations have been identified in Cretaceous fluvial sandstones and conglomerates, among which the most relevant is the Cerro Solo deposit (Chubut province) that corresponds to the paleochannel structure subtype. Other subtypes of sandstone model have been studied. For instance, the Don Otto deposit (Salta province), located in the Salta Group Basin (Cretaceous - Tertiary), belongs to the tabular U-V subtype. The roll front subtype can be also found in the Los Mogotes Colorados deposit (La Rioja province) which is hosted by Carboniferous continental sandstones. The uranium mineralisations in veins and disseminated episyenites within peraluminous leucogranites of the Sierras Pampeanas (Cordoba and San Luis provinces) represent other types of existing deposits. These granites are Devonian – Carboniferous and the related deposits are comparable to those from the Middle European Variscan. There are also other vein-type uranium deposits located in metamorphic basement in the periphery of high potassium calcalkaline granites (Sierras Pampeanas of Catamarca and La Rioja provinces), where the mineralisation control is mainly structural. The current uranium identified resources of the country are approximately 24,000 tU in the

Emplacement, petrological and magnetic susceptibility characteristics of diverse magmatic epidote-bearing granitoid rocks in Brazil, Argentina and Chile

Science.gov (United States)

Sial, A. N.; Toselli, A. J.; Saavedra, J.; Parada, M. A.; Ferreira, V. P.

1999-03-01

Magmatic epidote (mEp)-bearing granitoids from five Neoproterozoic tectonostratigraphic terranes in Northeastern (NE) Brazil, Early Palaeozoic calc-alkalic granitoids in Northwestern (NW) Argentina and from three batholiths in Chile have been studied. The elongated shape of some of these plutons suggests that magmas filled fractures and that dyking was probably the major mechanism of emplacement. Textures reveal that, in many cases, epidote underwent partial dissolution by host magma and, in these cases, may have survived dissolution by relatively rapid upward transport by the host magma. In plutons where such a mechanism is not evident, unevenly distributed epidote at outcrop scale is armoured by biotite or near-solidus K-feldspar aggregates, which probably grew much faster than epidote dissolution, preventing complete resorption of epidote by the melt. Al-in-hornblende barometry indicates that, in most cases, amphibole crystallized at P≥5 kbar. Kyanite-bearing thermal aureoles surrounding plutons that intruded low-grade metamorphic rocks in NE Brazil support pluton emplacement at intermediate to high pressure. mEp show overall chemical variation from 20 to 30 mol% (mole percent) pistacite (Ps) and can be grouped into two compositional ranges: Ps 20-24 and Ps 27-30. The highest Ps contents are in epidotes of plutons in which hornblende solidified under Pcorrosion of individual epidote crystals included in plagioclase in high-K calc-alkalic granitoids in NE Brazil, emplaced at 5-7 kbar pressure, yielded estimates of magma transport rate from 70 to 350 m year -1. Most of these plutons lack Fe-Ti oxide minerals and Fe +3 is mostly associated with the epidote structure. Consequently, magnetic susceptibility (MS) in the Neoproterozoic granitoids in NE Brazil, as well as Early Palaeozoic plutons in Argentina and Late Palaeozoic plutons in Chile, is usually low (3.0×10 -3 SI, typical of magnetite-series granitoids crystallized under higher oxygen fugacity. In NE

Oxygen isotope thermometry of quartz-Al2SiO5veins in high-grade metamorphic rocks on Naxos island (Greece)

Science.gov (United States)

Putlitz, Benita; Valley, John; Matthews, Alan; Katzir, Yaron

2002-04-01

Diffusion models predict that peak metamorphic temperatures are best recorded by the oxygen isotope fractionation between minerals in a bi-mineralic rock in which a refractory accessory mineral with slow oxygen diffusion rate is modally minor to a mineral with a faster diffusion rate. This premise is demonstrated for high-grade metamorphism on the island of Naxos, Greece, where quartz-kyanite oxygen isotope thermometry from veins in high-grade metamorphic pelites gives temperatures of 635-690 °C. These temperatures are in excellent agreement with independent thermometry for the regional M2 peak metamorphic conditions and show that the vein minerals isotopically equilibrated at the peak of metamorphism. Quartz-sillimanite fractionations in the same veins give similar temperatures (680+/-35 °C) and suggest that the veins grew near to the kyanite-sillimanite boundary, corresponding to pressures of 6.5 to 7.5 kbar for temperatures of 635-685 °C. By contrast, quartz-kyanite and quartz-biotite pairs in the host rocks yield lower temperature estimates than the veins (590-600 and 350-550 °C, respectively). These lower apparent temperatures are also predicted from calculations of diffusional resetting in the polyphase host-rock system. The data demonstrate that bimineralic vein assemblages can be used as accurate thermometers in high-temperature rocks whereas retrograde exchange remains a major problem in many polymineralic rocks.

Evolution of Migmatitic Granulite Complexes: implications from Lapland Granulite Belt, Part I: metamorphic geology

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Pekka Tuisku

2006-01-01

Full Text Available The Palaeoproterozoic Lapland granulite belt was juxtaposed between Archaean and Proterozoic terrains in the NE part of the Fennoscandian Shield concurrently with the accretion of Svecofennian arc complexes at ~1.9 Ga. The belt consists mainly of aluminous migmatiticmetagreywackes. Abundant noritic to enderbitic magmas were intruded concordantly into the metasediments and were probably an important heat source for metamorphism, which took place during the crystallization of the magmas. This is supported by structural and contact relations of metasediments and igneous rocks, and by the lack progressive metamorphic reaction textures in the igneous rock series. The peak of metamorphism took place above the dehydration melting temperature of the biotite-sillimanite-plagioclase-quartz assemblageat 750−850°C and 5−8.5 kbar which lead to formation of a restitic palaeosome and peraluminous granitic melt in metapelites. Subsequently, the rocks were decompressed and cooled below the wet melting temperature of pelitic rocks (650°C under the stability field of andalusite coexisting with potassium feldspar (2−3 kbar. Cooling was accompanied by the crystallization of the neosomes, often carrying aluminium-rich phases. Postmetamorphic duplexing of the LGB is clearly seen in the distribution of calculated PT conditions.

Pseudo- and real-inverted metamorphism caused by the superposition and extrusion of a stack of nappes: a case study of the Southern Brasília Orogen, Brazil

Science.gov (United States)

da Motta, Rafael Gonçalves; Moraes, Renato

2017-10-01

The Southern Brasília Orogen is a Neoproterozoic belt that occurs along the southernmost border of the São Francisco Craton where the Andrelândia Nappe System represents the subducted sedimentary domain and is divided into three allochthonous groups, of which the ages and P-T conditions of metamorphism are studied here. The basal unit, the Andrelândia Nappe, exhibits an inverted metamorphic pattern. The base of the structure, composed of staurolite, garnet, biotite, kyanite, quartz, and muscovite, marks the metamorphic peak, whereas at the top, the association of the metamorphic peak does not contain staurolite. The Liberdade Nappe, the middle unit, presents a normal metamorphic pattern; its base, close to the Andrelândia Nappe, shows paragneiss with evidence of in situ partial melting, and towards the top, coarse-grained staurolite schist is found. The staurolite-out and melt-in isograds are coincident and parallel to the main foliation. Thus, the shear zone that limits the nappes is syn-metamorphic, reheating the underlying Andrelândia Nappe and influencing the establishment of metamorphic inversion. This suggestion is supported by the monazite chemical ages, which indicates that the Andrelândia Nappe metamorphic peak (586 ± 15 Ma) is younger than that of the Liberdade Nappe (622.3 ± 7.6 Ma). The upper unit, the Serra da Natureza Klippe, bears a typical high-pressure granulite mineral assemblage that is composed of kyanite, garnet, K-feldspar, rutile, and leucosome, as well as a metamorphic peak at 604.5 ± 6.1 Ma. This tectonic assembly, with inverted and non-inverted metamorphic patterns and generation of klippen structures, is consistent with exhumation models and a strong indentor located in the lower continental crust.

Extensional ductile tectonics of the Sioule metamorphic series (Variscan French Massif Central)

Science.gov (United States)

Faure, M.; Grolier, J.; Pons, J.

1993-09-01

In the Northern part of the Variscan French Massif Central, the Sioule series, from top to bottom, consists of a pre-Viséan granite, migmatite, gneiss and mica schist. Two ductile deformations have been recognized. The earlier phase is characterized by a north-east-south-west trending stretching lineation; the second phase, characterized by a north-west-south-east trending mineral, stretching and crenulation lineation, is better marked in the lower mica schist part than in the upper granito-gneissic part. This second phase occurred during retrogression of the metamorphic rocks; related shear criteria indicate a top to the south-west shear. The Namurian-Westphalian magmatic bodies such as the Echassières leucogranite, Pouzol-Servant microgranite and numerous north-east -south-west trending microgranite dykes are emplaced in extensional fractures related to the same north-west-south-east maximum stretching direction. The asymmetrical shapes of the two granitic massifs indicate that they intruded towards the south-east. The synkinematic retrogression of the metamorphic rocks, the shape of the magmatic bodies and a re-examination of the numerous available data support the interpretation that the deformation is due to the extensional tectonic regime related to the Variscan crustal re-quilibration. This interpretation is in agreement with the correlation of the Sioule series with the Chavanon series. The two series belong to a unique tectono-metamorphic unit left-laterally offset by the Stephanian motion of the Sillon Houiller fault. This study also shows that the Sillon Houiller did not play a significant part during the Namurian-Westphalian extensional tectonics of the Massif Central.

Thermal modeling of pluton emplacement and associated contact metamorphism:Parashi stock emplacement in the Serranía de Jarara (Alta Guajira, Colombia

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Zuluaga C. Carlos A.

2010-12-01

Full Text Available

In the northernmost portion of the Serrania de Jarara (Alta Guajira, Colombia, low - medium grade metamorphic rocks from the Etpana Metamorphic Suite were thermally affected by emplacement of a small calc-alkaline intrusion (Parashi Stock. Detailed petrographic analysis in collected rock samples across the NE and NW plutonic contacts show occurrences of textural and mineralogical changes in the country rock fabric that evidence contact metamorphism overprinting regional metamorphism of the Etpana Suite. These changes include growth of andalusite (chiastolite, calcic clinopyroxeneand amphibole porphyroblast crosscutting Sn+1 metamorphicfoliation. Hornblende-plagioclase barometry (ca. 3.1 kbar and cooling models for the stock show maximum time temperature evolution in the country rock at the interpreted depth of intrusion (ca. 11 km and help to evaluate the behavior of the country rock with the changing local geotherm.

Primer registro de Vespula vulgaris (Hymenoptera: Vespidae en la Argentina First record of Vespula vulgaris (Hymenoptera: Vespidae in Argentina

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Maité Masciocchi

2010-12-01

Full Text Available Vespula vulgaris (Linnaeus es un véspido social nativo de la región Holártica. En este trabajo reportamos la primera detección de esta especie en Argentina. Obreras de esta avispa fueron capturadas cerca de la ciudad de San Carlos de Bariloche (Argentina en Febrero de 2010, mientras se tomaban muestras de otra avispa invasora, Vespula germanica (Fabricius o chaqueta amarilla, de morfología externa y hábitos similares a la anteriormente mencionada. Además, detallamos algunos caracteres de identificación y características biológicas.Vespula vulgaris (Linnaeus is a social vespid native to the Holarctic region. The first detection of this species in Argentina is here reported. Workers were captured close to San Carlos de Bariloche (Argentina during February 2010, while sampling for another successful invader, the German wasp or Yellowjacket, Vespula germanica (Fabricius. Both these wasp species are very similar morphologically and share a number of common habits. Also, some identification features and biological characters are here explained.

Breccia pipes in the Karoo Basin, South Africa, as conduits for metamorphic gases to the Early Jurassic atmosphere

Science.gov (United States)

Silkoset, Petter; Svensen, Henrik; Planke, Sverre

2014-05-01

The Toarcian (Early Jurassic) event was manifested by globally elevated temperatures and anoxic ocean conditions that particularly affected shallow marine taxa. The event coincided with the emplacement of the vast Karoo-Ferrar Large Igneous Province. Among the suggestions for trigger mechanisms for the climatic perturbation is metamorphic methane generation from black shale around the sills in the Karoo Basin, South Africa. The sill emplacement provides a mechanism for voluminous in-situ production and emission of greenhouse gases, and establishes a distinct link between basin-trapped and atmospheric carbon. In the lower stratigraphic levels of the Karoo Basin, black shales are metamorphosed around sills and the sediments are cut by a large number of pipe structures with metamorphic haloes. The pipes are vertical, cylindrical structures that contain brecciated and baked sediments with variable input of magmatic material. Here, we present borehole, petrographic, geochemical and field data from breccia pipes and contact aureoles based on field campaigns over a number of years (2004-2014). The metamorphism around the pipes show equivalent metamorphic grade as the sediments around nearby sills, suggesting a more prominent phreatomagmatic component than previously thought. The stratigraphic position of pipes and the breccia characteristics strengthens the hypothesis of a key role in the Toarcian carbon isotope excursion.

Unemployment Assistance and Transition to Employment in Argentina

NARCIS (Netherlands)

A. Iturriza (Ana); A.S. Bedi (Arjun Singh); R.A. Sparrow (Robert)

2007-01-01

textabstractIn 2001-02, Argentina experienced a wrenching economic crisis. Plan Jefes, implemented in May 2002, was Argentina's institutional response to the increases in unemployment and poverty triggered by the crisis. The program provided a social safety net and appears to have successfully

Tabaquismo durante el embarazo en Argentina y Uruguay Smoking during pregnancy in Argentina and Uruguay

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Fernando Althabe

2008-02-01

Full Text Available Argentina y Uruguay están entre los países con mayor proporción de mujeres jóvenes fumadoras. Se desconoce cuál es la proporción exacta de ellas que fuman durante el embarazo así como las características de las que dejan de fumar y las que continúan fumando durante el embarazo. Realizamos una encuesta administrada por un/a entrevistador/a a 1512 mujeres embarazadas de 18 años o mayores (796 en Argentina; 716 en Uruguay, que concurrían a control prenatal en hospitales públicos de grandes conglomerados urbanos. 44% de las mujeres en Argentina y 53% en Uruguay habían sido o eran fumadoras. Durante el embarazo, 11% de las mujeres en Argentina y 18% en Uruguay continuaron fumando. En ambos países, la proporción de mujeres que vive con fumadores, permite fumar en el hogar y regularmente o siempre se encuentra en lugares cerrados con personas que estén fumando fue 49%, 46% y 20% entre las mujeres que nunca fumaron, 67%, 60% y 32% entre las que dejaron, y 78%, 75% y 52% entre las que continuaron fumando respectivamente. El estudio confirma un importante problema de salud pública y documenta que la exposición ambiental persiste en subgrupos de mujeres, aun en aquéllas que dejaron de fumar. Es importante que el sector de salud pública provea acceso a programas efectivos para dejar de fumar durante el embarazo. Cualquier nueva intervención a desarrollar que intente tener un éxito al menos moderado y sostenible, debiera incluir componentes que actúen sobre el entorno fumador de la mujer embarazada que fuma.Argentina and Uruguay are among the countries in which a large proportion of young women smoke. The rate of smokers during pregnancy in both countries is not well known, and data on the characteristics of women who quit smoking during pregnancy compared to those who continue smoking are not available. We conducted a survey including 1512 pregnant women >18 years old (796 in Argentina; 716 in Uruguay, during antenatal visits in

The bloodsucking biting midges of Argentina (Diptera: Ceratopogonidae

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Gustavo R Spinelli

2005-04-01

Full Text Available A key is presented for the identification of the adults of 54 species of bloodsucking ceratopogonids, 51 of which are known inhabitants of Argentina, and Culicoides uruguayensis Ronderos, C. pifanoi Ortiz, and C. trilineatus Fox, which are known to occur in bordering Uruguay and Paraguay. Wing photographs are provided of females of the 45 species of Culicoides. Three new species of Culicoides Latreille from Northeastern Argentina are described and illustrated: C. austroparaensis Spinelli, C. bachmanni Spinelli, and C. williamsi Spinelli. The following six species are recorded for the first time from Argentina and/or bordering localities in Paraguay: Leptoconops brasiliensis (Lutz, C. gabaldoni Ortiz, C. ginesi Ortiz, C. pifanoi Ortiz, C. pseudocrescentis Tavares and Luna Dias, and C. trilineatus; and C. estevezae Ronderos and Spinelli is newly recorded from Misiones province of Argentina. C. lopesi Barretto is excluded from the Argentinean ceratopogonid fauna.

Diffusion models in metamorphic thermo chronology: philosophy and methods

International Nuclear Information System (INIS)

Munha, Jose Manuel; Tassinari, Colombo Celso Gaeta

1999-01-01

Understanding kinetics of diffusion is of major importance to the interpretation of isotopic ages in metamorphic rocks. This paper provides a review of concepts and methodologies involved on the various diffusion models that can be applied to radiogenic systems in cooling rocks. The central concept of closure temperature is critically discussed and quantitative estimates for the various diffusion models are evaluated, in order to illustrate the controlling factors and the limits of their practical application. (author)

Nuevas citas de Coleoptera acuáticos y Megaloptera para la provincia de Chubut (Argentina New records of aquatic Coleoptera and Megaloptera from Chubut province (Argentina

Directory of Open Access Journals (Sweden)

Miguel Archangelsky

2004-12-01

Full Text Available Se informa acerca de nuevos hallazgos de coleópteros acuáticos, de Dytiscidae, Gyrinidae, Hydrophilidae y Elmidae para la provincia de Chubut (Argentina. También se cita por primera vez a las Sialidae (Megaloptera, género Protosialis Weele, para la República Argentina.New records of aquatic Coleoptera, in the families Dytiscidae, Gyrinidae, Hydrophilidae and Elmidae, are reported for the Chubut province (Argentina. The Sialidae (Megaloptera, genus Protosialis Weele, is reported for the first time in Argentina.

Horizontalidad, autogestión y protagonismo en Argentina

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Marina Sitrin

2010-02-01

Full Text Available Este artículo trata los movimientos sociales autónomos que surgieron después de la crisis económica y la posterior rebelión popular en Argentina en diciembre de 2001. Los movimientos autónomos en la Argentina, como tantos movimientos en el mundo de hoy, son movimientos basados en la creación de nuevas relaciones sociales y comunidades ahora, al mismo tiempo que proyectan nuevas sociedadesy las relaciones en y para el futuro. Son movimientos con una concepción diferente del tiempo y el espacio. Son movimientos queentienden lo individual y lo colectivo como vinculados entre sí. Hay mucho en común entre la experiencia en la Argentina y las prácticas eideas anarquistas. Eso no significa que los que están creando nuevas relaciones y comunidades en la Argentina sean anarquistas. Lo que este artículo intenta hacer es basarse en las experiencias de los movimientos sociales argentinos para iniciar una reflexión sobre lasprácticas e ideas que los anarquistas pueden prestar a los distintos movimientos y comunidades autónomas; y, a su vez, sobre lo que los movimientos autónomos en la Argentina puede dar a las ideas y prácticas anarquistas.

SHRIMP chronology of the Magallanes Basin basement, Tierra del Fuego: Cambrian plutonism and Permian high-grade metamorphism Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: plutonismo Cámbrico y metamorfismo Pérmico de alto grado

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Francisco Hervé

2010-07-01

Full Text Available Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC, obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma, interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could nave been an important source of detritus for the conglomeratic Permian and Triassic? Successions of neighboring regions in South America, Africa and Antarctica.Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y

Chemical-Petrographic Types and Shock Metamorphism of 184 Grove Mountains Equilibrated Ordinary Chondrites

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Deqiu Dai

2018-06-01

Full Text Available We reported the petrography and mineral chemistry of 184 equilibrated ordinary chondrites collected from Grove Mountains, Antarctica. The chemical-petrographic types and shock metamorphism degrees of these chondrites were assigned. They were classified into 46 H groups (22 H4, 20 H5, and four H6, 133 L groups (eight L4, 75 L5, and 50 L6, and five LL groups (four LL4 and one LL5. Some of these chondrites could be paired; however, both H and L group meteorites were affected. Further studies such as terrestrial ages and thermal luminescence are required in order to confirm the pairings. The relative abundances of H, L, and LL are different in Grove Mountain meteorites, when compared to those in Transcontinental Ridge meteorites. Based on the shock effects, the shock metamorphism degrees of these chondrites were assigned. Compared to previous studies, the heavily shocked samples of S4 and S5 have a higher fraction (59 out of 184 in Grove Mountain ordinary chondrites. The L group (54 out of 59 is the dominant chemical group in the heavily shocked chondrites, except for five meteorites which belong to the H group. The shock metamorphism degrees of the H and L groups are distinct, which may indicate different surface properties in their parent bodies. In addition, the petrologic types and shock degrees are probably closely related, with the most heavily shocked chondrites observed in types 5 and 6.

Neoarchean metamorphism recorded in high-precision Sm-Nd isotope systematics of garnets from the Jack Hills (Western Australia)

Science.gov (United States)

Eccles, K. A.; Baxter, E. F.; Mojzsis, S. J.; Marschall, H.; Williams, M. L.; Jercinovic, M. J.

2013-12-01

Studies of metasedimentary rocks from the Jack Hills, which host Earth's oldest known detrital minerals, have focused on zircon and occasionally monazite or xenotime, but no attention has been directed toward one of the most common mineral markers of metamorphism: garnet. Garnet can provide a record of the post-depositional, prograde metamorphic history of Archean metasedimentary rocks. Additionally, the use of a newly developed detrital garnet dating technique [1,2] may reveal information about pre-depositional metamorphism that could address lingering questions about the nature and timing of Earth's earliest tectonometamorphic events. Here we investigate garnet from the Jack Hills metasedimentary rocks to test whether they record in situ metamorphism or are a detrital relict of even older metamorphic events. We identified garnet in two bulk quartz-pebble conglomerate samples collected from the 'discovery' outcrop at Eranondoo Hill in the Jack Hills of Western Australia. Electron microprobe analyses of polished grains and SEM measurements of unpolished grain surfaces are consistent, revealing garnet composition indicative of a single generation/population of predominantly almandine-spessartine solid solution (~10-35% mole fraction spessartine). Compositional maps of garnet grains reveal little zoning and no discontinuities, most consistent with a single growth event. Dating Jack Hills' garnet via the Sm-Nd system is possible due to continued development of small sample analysis techniques, including running NdO+ TIMS analyses with Ta2O5 activator [3] permitting Ma for two point isochrons between clean garnet (Sm/Nd ≥ 1.0) and their leached inclusion populations [2]. Four grouped garnet grain separates from one sample yield preliminary dates of 2703.6×6.0Ma, 2612.4×6.0Ma, 2605.0×5.5Ma, and 2567.3×8.3Ma, while the second sample yielded a date of 2579.6×4.6 Ma (2σ). Compositional and geochronologic data indicate likely in situ garnet growth during a late

The regulatory control of radioactive sources in Argentina

Energy Technology Data Exchange (ETDEWEB)

Rojkind, Roberto Hector [Autoridade Regulatoria Nuclear, Buenos Aires (Argentina)

1997-12-31

Argentina has been conducting nuclear activities for more than forty years, and as early as in 1956 established a Regulatory Authority. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations had been set in Argentina, before the accident in Goiania. The conclusions drawn from that accident encouraged in Argentina the improvement of some regulatory procedures and helped to enhance the quality of the regulatory process. Therefore, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain improved. Some lessons learned in Argentina from the accident in Goiania and the main characteristics of an effective enforcement program helpful to prevent radiological accidents in industrial, medical, research and teaching uses of radioactive sources are presented. (author) 9 refs; e-mail: rrojkind at sede.arn.gov.br

Control of gaseous emissions in central Costanera S.A. of Argentina; Control de emisiones gaseosas en central Costanera S. A. de Argentina

Energy Technology Data Exchange (ETDEWEB)

Brabenec, Edgardo [Unidad de Negocios Central Costanera, S. A., (Argentina)

1997-12-31

A description is presented of the equipment utilized at the Central Costanera, S.A. of Argentina, the requirements and the Environmental Management established for this Power Station, and the Standards and the resolutions and law instruments on Environmental issues. Also it is presented the Environmental Management plan of the Ente Nacional Regulador de Electricidad of Argentina as well as the controls and environmental corrective actions implemented at the Central Costanera, S.A. [Espanol] Se presenta una descripcion del equipo utilizado en la Central Costanera S.A. de Argentina, los requerimientos de gestion ambiental establecidos para esta central y las normas, resoluciones e instrumentos juridicos en materia ambiental. Se presenta ademas el plan de gestion ambiental del Ente Nacional Regulador de la Electricidad de Argentina asi como los controles y acciones correctivas ambientales implantadas en la Central Costanera S. A.

Control of gaseous emissions in central Costanera S.A. of Argentina; Control de emisiones gaseosas en central Costanera S. A. de Argentina

Energy Technology Data Exchange (ETDEWEB)

Brabenec, Edgardo [Unidad de Negocios Central Costanera, S. A., (Argentina)

1996-12-31

A description is presented of the equipment utilized at the Central Costanera, S.A. of Argentina, the requirements and the Environmental Management established for this Power Station, and the Standards and the resolutions and law instruments on Environmental issues. Also it is presented the Environmental Management plan of the Ente Nacional Regulador de Electricidad of Argentina as well as the controls and environmental corrective actions implemented at the Central Costanera, S.A. [Espanol] Se presenta una descripcion del equipo utilizado en la Central Costanera S.A. de Argentina, los requerimientos de gestion ambiental establecidos para esta central y las normas, resoluciones e instrumentos juridicos en materia ambiental. Se presenta ademas el plan de gestion ambiental del Ente Nacional Regulador de la Electricidad de Argentina asi como los controles y acciones correctivas ambientales implantadas en la Central Costanera S. A.

Subduction metamorphism in the Himalayan ultrahigh-pressure Tso Morari massif: An integrated geodynamic and petrological modelling approach

Science.gov (United States)

Palin, Richard M.; Reuber, Georg S.; White, Richard W.; Kaus, Boris J. P.; Weller, Owen M.

2017-06-01

The Tso Morari massif is one of only two regions where ultrahigh-pressure (UHP) metamorphism of subducted crust has been documented in the Himalayan Range. The tectonic evolution of the massif is enigmatic, as reported pressure estimates for peak metamorphism vary from ∼2.4 GPa to ∼4.8 GPa. This uncertainty is problematic for constructing large-scale numerical models of the early stages of India-Asia collision. To address this, we provide new constraints on the tectonothermal evolution of the massif via a combined geodynamic and petrological forward-modelling approach. A prograde-to-peak pressure-temperature-time (P-T-t) path has been derived from thermomechanical simulations tailored for Eocene subduction in the northwestern Himalaya. Phase equilibrium modelling performed along this P-T path has described the petrological evolution of felsic and mafic components of the massif crust, and shows that differences in their fluid contents would have controlled the degree of metamorphic phase transformation in each during subduction. Our model predicts that peak P-T conditions of ∼2.6-2.8 GPa and ∼600-620 ∘C, representative of 90-100 km depth (assuming lithostatic pressure), could have been reached just ∼3 Myr after the onset of subduction of continental crust. This P-T path and subduction duration correlate well with constraints reported for similar UHP eclogite in the Kaghan Valley, Pakistan Himalaya, suggesting that the northwest Himalaya contains dismembered remnants of what may have been a ∼400-km-long UHP terrane comparable in size to the Western Gneiss Region, Norway, and the Dabie-Sulu belt, China. A maximum overpressure of ∼0.5 GPa was calculated in our simulations for a homogeneous crust, although small-scale mechanical heterogeneities may produce overpressures that are larger in magnitude. Nonetheless, the extremely high pressures for peak metamorphism reported by some workers (up to 4.8 GPa) are unreliable owing to conventional thermobarometry

Magnetotelluric investigation in and around southern part of Hidaka metamorphic belt in Hokkaido, Japan; Hidaka henseitai nanbuiki ni okeru MT kansoku

Energy Technology Data Exchange (ETDEWEB)

Sato, H; Utsugi, M; Hirano, K; Doi, T; Nishida, Y; Arita, K [Hokkaido University, Sapporo (Japan)

1996-05-01

An MT observation was conducted in the Hidaka district, Hokkaido, for the estimation of the 2D resistivity structure in the southern part of the metamorphic belt, when frequencies of the VLF, ELF, and ULF bands were used. An approximately 42km-long traverse line was set to cross the Hidaka metamorphic belt from east to west. As for the observation points, 48 VLF points, 16 ELF points, and 4 ULF points were provided. During the data processing, impedance tensor was calculated in the frequency domain for the determination of the apparent resistivity relative to frequency and the phase difference. As the result, it was found that there is a fairly large resistivity gap between observation spots MNS and KWR and that the boundary corresponds to the Hidaka metamorphic belt, that the metamorphic belt that is reflected as a conspicuous high-resistivity layer in the VLF-, ELF-MT slopes down toward the east and has a distribution as deep as 10km in the vicinity of observation point KWR, that this high-resistivity layer sandwiches a low-resistivity layer at a depth of 5-7km, and that on the east side of the metamorphic belt there is a medium-resistivity layer creeping under the belt from the east side toward the west side. 5 refs., 6 figs.

Prospect for Development of Open Access in Argentina

Science.gov (United States)

Miguel, Sandra; Bongiovani, Paola C.; Gomez, Nancy D.; Bueno-de-la-Fuente, Gema

2013-01-01

This perspective article presents an overview of the Open Access movement in Argentina, from a global and regional (Latin American) context. The article describes the evolution and current state of initiatives by examining two principal approaches to Open Access in Argentina: "golden" and "green roads". The article will then…

Metamorphic P-T conditions and CO2 influx history of medium-grade metapelites from Karakorum, Trans-Himalaya, India

Science.gov (United States)

Sachan, Himanshu K.; Santosh, M.; Prakash, Divya; Kharya, Aditya; Chandra Singh, P.; Rai, Santosh K.

2016-07-01

The medium grade metapelites of Pangong-Tso area in the trans-Himalayan region underwent sillimanite-grade metamorphism initiated during the Cretaceous, associated with the collision of the Kohistan arc and the Indian plate with Asia. This paper present results from a petrological and fluid inclusion study to understand the metamorphic P-T conditions and fluid history of these rocks. The calculated phase equilibria in the Na2O-CaO-K2O-FeO-MgO-MnO-Al2O3-SiO2-H2O-TiO2 (NCKFMMnASHT) system suggest P-T conditions of 8 kbar and 650 °C for the peak metamorphic event. Primary fluid inclusions occur in staurolite and garnet, whereas quartz carries mostly secondary fluid inclusions. The trapped fluids in primary inclusions show initial melting temperatures in the range of -56.9 to -56.6 °C, suggesting nearly pure CO2 composition. The secondary fluids are of mixed carbonic-aqueous nature. The re-equilibrated inclusions show annular morphology as well as necking phenomena. The CO2 isochores for the primary inclusions indicate pressures of 6.1-6.7 kbar, suggesting that the CO2-rich fluids were trapped during post-peak exhumation of the rocks, or that synmetamorphic carbonic fluids underwent density reversal during isothermal decompression. The secondary CO2-H2O fluids must have been trapped during the late exhumation stage, as their isochores define further lower pressures of 4.8 kbar. The morphology of re-equilibrated fluid inclusions and the rapid decrease in pressure are consistent with a near-isothermal decompression trajectory following the peak metamorphism. The carbonic fluids were probably derived locally from decarbonation reactions of the associated carbonate rocks during metamorphism or from a deep-seated reservoir through Karakorum fault.

A metamorphic controller for plant control system design

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Tomasz Klopot

2016-07-01

Full Text Available One of the major problems in the design of industrial control systems is the selection and parameterization of the control algorithm. In practice, the most common solution is the PI (proportional-integral controller, which is simple to implement, but is not always the best control strategy. The use of more advanced controllers may result in a better efficiency of the control system. However, the implementation of advanced control algorithms is more time-consuming and requires specialized knowledge from control engineers. To overcome these problems and to support control engineers at the controller design stage, the paper describes a tool, i.e., a metamorphic controller with extended functionality, for selection and implementation of the most suitable control algorithm. In comparison to existing solutions, the main advantage of the metamorphic controller is its possibility of changing the control algorithm. In turn, the candidate algorithms can be tested through simulations and the total time needed to perform all simulations can be less than a few minutes, which is less than or comparable to the design time in the concurrent design approach. Moreover, the use of well-known tuning procedures, makes the system easy to understand and operate even by inexperienced control engineers. The application was implemented in the real industrial programmable logic controller (PLC and tested with linear and nonlinear virtual plants. The obtained simulation results confirm that the change of the control algorithm allows the control objectives to be achieved at lower costs and in less time.

Determination of fluorine by proton induced gamma ray emission (PIGE) spectrometry in igneous and metamorphic charnockitic rocks from Rogaland (S.W. Norway)

International Nuclear Information System (INIS)

Roelandts, I.; Robaye, G.; Weber, G.; Delbrouck, J.M.; Duchesne, J.C.

1986-01-01

More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S.W. Norway) have been analysed by a direct non-destructive proton induced gamma ray emission (PIGE) technique. The fluorine contents vary from < 25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal concentrations of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions. (author)

Investigation of In0.7Ga0.3As/In0.7Al0.3As metamorphic HEMT- heterostructures by photoluminescence spectroscopy

International Nuclear Information System (INIS)

LETT', Prof. Popova 5, St. Petersburg 197376 (Russian Federation))" data-affiliation=" (Saint-Petersburg Electrotechnical University LETT', Prof. Popova 5, St. Petersburg 197376 (Russian Federation))" >Romanovskiy, D S; LETT', Prof. Popova 5, St. Petersburg 197376 (Russian Federation))" data-affiliation=" (Saint-Petersburg Electrotechnical University LETT', Prof. Popova 5, St. Petersburg 197376 (Russian Federation))" >Tarasov, S A; Galiev, G B; Pushkarev, S S

2014-01-01

Low-temperature photoluminescence and photoreflectance have been studied in several metamorphic HEMT- (MHEMT-) heterostructures with the same active regions and different buffer layer designs grown by solid-source molecular beam epitaxy. The indium mole fraction in InAlAs/InGaAs/InAlAs single quantum well (QW) is 0.7. It was found that structures with step-graded metamorphic buffer have better quality. Also it was shown that mismatched superlattices in metamorphic buffer can influence on the half-width of photoluminescence spectra. The possible attribution of photoluminescence and photoreflectance spectral lines and their thermal behaviour are critically discussed

Economy-wide impacts of biofuels in Argentina

International Nuclear Information System (INIS)

Timilsina, Govinda R.; Chisari, Omar O.; Romero, Carlos A.

2013-01-01

Argentina is one of the world's largest biodiesel producers and the largest exporter, using soybeans as feedstock. Using a computable general equilibrium model that explicitly represents the biofuel industry, this study carries out several simulations on two sets of issues: (i) international markets for biofuel and feedstock, such as an increase in prices of soybean, soybean oil, and biodiesel, and (ii) domestic policies related to biofuels, such as an introduction of biofuel mandates. Both sets of issues can have important consequences to the Argentinean economy. The simulations indicate that increases in international prices of biofuels and feedstocks would increase Argentina's gross domestic product and social welfare. Increases in international prices of ethanol and corn also can benefit Argentina, but to a lesser extent. The domestic mandates for biofuels, however, would cause small losses in economic output and social welfare because they divert part of biodiesel and feedstock from exports to lower-return domestic consumption. An increase in the export tax on either feedstock or biodiesel also would lead to a reduction in gross domestic product and social welfare, although government revenue would rise. - Highlights: ► Argentina is one of the largest biodiesel producer and exporter using soybeans. ► Economy-wide impacts are assessed using a CGE model for Argentina. ► Policies simulated are feedstock and biodiesel price change, and domestic mandates. ► Increases in international prices of biofuels and feedstock benefit the country. ► Domestic mandates for biofuels cause small losses in economic output

Tareas que realizan los bibliotecarios universitarios en Argentina

Directory of Open Access Journals (Sweden)

Werner Agazzi

2011-08-01

Full Text Available El presente estudio es una investigación descriptiva que pretende conocer las tareas que realizan los bibliotecarios en las bibliotecas universitarias argentinas, abordando el tema desde la perspectiva de las competencias laborales y el actual perfil del bibliotecario universitario. Mediante la utilización de un cuestionario enviado a las direcciones de e-mail de bibliotecas universitarias argentinas se compilaron datos sobre las tareas que realizan los bibliotecarios en esas instituciones. A través de este proceso también se compilaron datos relacionados con las tareas de comunicación vía e-mail por parte de las bibliotecas universitarias argentinas.

Evidence of an upper ordovician thermo-metamorphic event in the SW-Corner of the Cantabrian Mountains (N-Spain

Directory of Open Access Journals (Sweden)

Krumm, S.

1992-12-01

Full Text Available According to Illite «crystallinity» (IC data, the metamorphic evolution of the SW Cantabrian Mountains took place in several steps. After a Precambrian deformation with accompanying low-grade metamorphism a thermal event during the Upper Ordovician affected the Cambro-Ordovician sediments. This event is marked by anchizonal IC values in the Pre-Silurian sequence contrasting the diagenetic data obtained from Siluro-Devonian rocks.Apparently, the metamorphic history in that part of the Cantabrian Mountains ended during the Late Ordovician, a Hercynian metamorphism cannot be proven conclusively.Segun la cristalinidad de Illita (IC la evolución metamórfica de la zona sudoeste de la Cordillera Cantábrica tuvo lugar en varias etapas. Siguiendo una deformación precámbrica con un metamorfismo de bajo grado, un evento térmico durante el Ordovícico Superior afecto a la secuencia Cambro-Ordovícica. Este evento esta marcado en las rocas pre-Silúricas por valores de IC indicando la anchizona. Estos datos contrastan con valores obtenidos de la secuencia Siluro-Devónica, que son característicos de la diagénesis.Aparentemente, la evolución metamórfica del sudoeste de la Cordillera Cantábrica termino durante el Ordovícico, un metamorfismo Hercínico no pudo ser comprobado.

Computing and Education in Argentina, Uruguay and Paraguay.

Science.gov (United States)

Sadowsky, Manuel

Although the report is specifically about Argentina, Uruguay and Paraguay, the considerations presented are valid for all of Latin America. In September, 1969, Argentina had approximately 200 electronic computers. The annual growth is estimated at 15-20% and the implementation of teleprocessing and time-sharing systems have made evident the…

Radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico with annotated bibliography

International Nuclear Information System (INIS)

McLemore, V.T.

1982-01-01

From an extensive literature search and field examination of 96 nonsandstone radioactive occurrences, the author compiled an annotated bibliography of over 600 citations and a list of 327 radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico. The citations are indexed by individual radioactive occurrence, geographic area, county, fluorspar deposits and occurrences, geochemical analyses, and geologic maps. In addition, the geology, mineralization, and uranium and thorium potential of 41 geographic areas in New Mexico containing known radioactive occurrences in veins and igneous and metamorphic rocks or that contain host rocks considered favorable for uranium or thorium mineralization are summarized. A list of aerial-radiometric, magnetic, hydrogeochemical, and stream-sediment survey reports is included

The nuclear research centre at Bariloche, Argentina

International Nuclear Information System (INIS)

Abriata, J.P.

2001-01-01

The nuclear research centre at Bariloche (CAB) is one of the four centres under the Atomic Energy Commission of Argentina (CNEA). The research programme of CAB addresses various issues like nuclear reactor development, nuclear fuel and fuel cycle, applications of radioisotopes and radiation, and waste management. There is also a basic nuclear science component. The human resource development in the areas of physics and nuclear engineering is done in an associated Balseiro Institute which has undergraduate and graduate programmes as well as doctoral and postdoctoral research. The Centre interacts well with the society and provides services in the nuclear area. It has a close interaction with the nuclear sector of Argentina as also with many international organisations. Regulatory control over the Centre is carried out by the Nuclear Regulatory Authority of Argentina. (author)

The energy sector in Argentina

International Nuclear Information System (INIS)

2016-01-01

This article first outlines that Argentina produces an important part of its hydrocarbon consumption and comment various aspects of this production: hydrocarbons are at the heart of the Argentinian energetic model; conventional hydrocarbon reserves are however decreasing; the public operator remains the main actor even though the market is opened to multinational companies. The article then describes the crisis faced by this energetic model: the energy balance is now a burden; the increasing unbalance between production and consumption can be explained by supply-related as well as demand-related factors; authorities must intervene on hydrocarbon prices and subsidize the oil price on the domestic market. It appears that the future for hydrocarbons in Argentina relies on non-conventional hydrocarbons. Bio-fuels, a key sector of the Argentinian economy, are a matter of trade dispute with the EU and the USA. Apart from hydroelectricity (some new projects are planned), renewable energies are very few developed in Argentina. Appendices propose a graph of the distribution of energy consumption among the different sources, a map indicating locations of the main exploited hydrocarbon deposits, a presentation of mechanisms implemented to subsidize hydrocarbon production

Nuclear safeguards in Brazil and Argentina: 25 years of ABACC

Science.gov (United States)

Kassenova, Togzhan

2017-11-01

As possessors of advanced nuclear technology, Brazil and Argentina bear special responsibility for helping the international community and neighbors in their region feel confident that their nuclear programs are peaceful, secure, and safe. Over the past 25 years, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) has played an indispensable role in strengthening such confidence by implementing nuclear safeguards in the two countries. Today, ABACC carries out safeguards inspections at a total of 76 nuclear facilities in Brazil and Argentina. This article describes how Brazil and Argentina view trends in the global nonproliferation regime and international nuclear safeguards, and explains how these trends relate to unique challenges and opportunities facing Brazil, Argentina, and ABACC.

Constraining metamorphic rates through allanite and monazite petrochronology: a case study from the Miyar Valley (High Himalayan Crystalline of Zanskar, NW India)

Science.gov (United States)

Robyr, Martin; Goswami-Banerjee, Sriparna

2014-05-01

Dating metamorphic rocks raises specific issues because metamorphism comprises a complex sequence of structural changes and chemical reactions that can be extended over millions or tens of millions of years so that metamorphic rocks cannot in general be said to have "an age". Therefore, an accurate interpretation of radiometric age data from metamorphic rocks requires first to establish the behavior of the isotopic system used for dating relative to the pressure and temperature (P-T) conditions that a metamorphic rock experienced. As the U-Th-Pb system in LREE-accessory phases like monazite and allanite is not easily reset during subsequent temperature increase, allanite and monazite U-Th-Pb ages are collectively interpreted as reflecting crystallization ages. As a consequence, to correctly interpret allanite and monazite crystallization ages, it is essential to accurately determine the physical conditions of their crystallization. A meticulous account of the chemical and textural evolution of monazite and allanite along a well constrained prograde pelitic sequence of the High Himalayan Crystalline of Zanskar (Miyar Valley; e.g. Robyr et al., 2002; 2006; 2014) reveals that: (1) the occurrence of the first metamorphic allanite coincides with the biotite-in isograd and (2) the formation of the first metamorphic monazite occurs at the staurolite-in isograd. The finding of both monazite and allanite as inclusion in staurolite porphyroblasts indicates that the breakdown of allanite and the formation of monazite occurred during staurolite crystallization. Thermobarometry results show that the metamorphic allanites are appeared in the 400-420 °C, while the signature of the first metamorphic monazite is found at ~ 600 °C with staurolite-in isograd. Allanite and monazite U-Th-Pb ages thus constrain the timing when the rocks reached the ~ 420 °C and ~ 600 °C isotherms respectively. In situ LA-ICPMS dating of coexisting allanite and monazite inclusions in garnet

Communications received from Argentina and Brazil

International Nuclear Information System (INIS)

1988-05-01

The document reproduces the Joint Declaration on Nuclear Policy signed by the Presidents of Argentina and Brazil on 30 November 1985, the Protocol on Nuclear Co-operation between Argentina and Brazil signed on 10 December 1986, the Joint Declaration on Nuclear Policy signed by the two Presidents on 10 December 1986, the Joint Declaration on Nuclear Policy signed by the two Presidents on 17 July 1987 and the Joint Declaration on Nuclear Policy (IPERO Declaration) signed by the two Presidents on 8 April 1988

On protolith-, metamorphic overprint, microstructure and rheology of mineral assemblages in orogenic peridotites of the central Scandinavian Caledonides

Science.gov (United States)

Gilio, Mattia; Clos, Frediano; Van Roermund, Herman L. M.

2013-04-01

The Scandinavian Caledonides (SC) are a deeply eroded Alpine-type orogenic belt formed by closure of the Iapetus ocean and collision between Baltica and Laurentia (500-380 Ma). The SC consists of a stack of Nappe Complexes (from bottom to top called Lower, Middle, Upper and Uppermost Allochthons) thrusted to the east over the Baltic Shield (Brueckner and Van Roermund, 2004; Gee et al., 2008). Fossil lithospheric mantle fragments, called orogenic peridotites, have been found within the (upper part of) middle, upper and uppermost Allochthons, as well as in the reworked basement gneisses (a.o Western Gneiss Complex (WGC)) along the Norwegian west coast. They occur as isolated lenses that contain diverse mineral parageneses and/or bulk rock compositions. Crustal incorporation of orogenic peridotite is classically interpreted to be the result of plate collisional processes related to orogeny (Brueckner and Medaris, 2000). The WGC and parts of the upper part of the Middle Allochthon (a.o. Seve Nappe Complex (SNC) in N Jämtland/S Västerbotten, central Sweden), are well known for the occurrence of high (HP) and ultrahigh pressure (UHP) metamorphic terranes (of Caledonian age). The (U)HPM evidence clearly demonstrates the deep metamorphic origin of these rocks interpreted to be caused by continental subduction and/or collision. Other metamorphic rocks (of Caledonian age) exposed in allochthonous nappes are solely characterised by greenschist-, amphibolite- and/or MP granulite "facies" mineral assemblages that can be interpreted, in the absence of retrogression, to have formed in less deeply subducted (and/or metamorphic) environments. This duality in metamorphic "facies" allows for a discrimination (at least theoretically) between "deep" versus "shallow" rooted nappes (in central parts of the Scandinavian Caledonides). Conform this reasoning, this duality should also be present within the Caledonian mineral assemblages (= metamorphic overprint) of orogenic peridotites (in

Mid amphibolite facies metamorphism of harzburgites in the Neoproterozoic Cerro Mantiqueiras Ophiolite, southernmost Brazil

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HARTMANN LÉO A.

2003-01-01

Full Text Available Valuable information is retrieved from the integrated investigation of the field relationships, microstructure and mineral compositions of harzburgites from the Neoproterozoic Cerro Mantiqueiras Ophiolite. This important tectonic marker of the geological evolution of southernmost Brazilian Shield was thoroughly serpentinized during progressive metamorphism, because the oldest mineral assemblage is: olivine + orthopyroxene + tremolite + chlorite + chromite. This M1 was stabilized in mid amphibolite facies - 550-600ºC as calculated from mineral equilibria. No microstructural (e.g. ductile deformation of olivine or chromite or compositional (e.g. mantle spinel remnant of mantle history was identified. A metamorphic event M2 occurred in the low amphibolite facies along 100 m-wide shear zones, followed by intense serpentinization (M3 and narrow 1-3 m-wide shear zones (M4 containing asbestos.

Enzyme clusters during the metamorphic period of Ambystoma mexicanum: role of thyroid hormone

NARCIS (Netherlands)

Lamers, W. H.; Mooren, P. G.; de Graaf, A.

1982-01-01

Enzyme activities and DNA content have been measure in axolotl liver during the metamorphic period (4-8 months after spawning). Three different types of enzyme activity profiles were observed. In the type I profile (carbamoyl-phosphate synthase, arginase, ornithine transcarbamoylase, and glutamate

Photoelectric properties of the metamorphic InAs/InGaAs quantum dot structure at room temperature

Energy Technology Data Exchange (ETDEWEB)

Golovynskyi, S. L., E-mail: golovynskyi@isp.kiev.ua [Institute of Semiconductor Physics, National Academy of Sciences, pr. Nauki 45, 03028 Kyiv (Ukraine); Seravalli, L.; Trevisi, G.; Frigeri, P.; Gombia, E. [Institute of Materials for Electronics and Magnetism, CNR-IMEM, Parco delle Scienze 37a, I-43100 Parma (Italy); Dacenko, O. I.; Kondratenko, S. V. [Department of Physics, Taras Shevchenko National University of Kyiv, 64 Volodymyrska St., 01601 Kyiv (Ukraine)

2015-06-07

We present the study of optical and photoelectric properties of InAs quantum dots (QDs) grown on a metamorphic In{sub 0.15}Ga{sub 0.85}As buffer layer: such nanostructures show efficient light emission in the telecom window at 1.3 μm (0.95 eV) at room temperature. We prepared a sample with vertical geometry of contacts isolated from the GaAs substrate. The structure is found to be photosensitive in the spectral range above 0.9 eV at room temperature, showing distinctive features in the photovoltage and photocurrent spectra attributed to QDs, InAs wetting layer, and In{sub 0.15}Ga{sub 0.85}As metamorphic buffer, while a drop in the photoelectric signal above 1.36 eV is related to the GaAs layer. No effect of defect centers on the photoelectrical properties is found, although they are observed in the absorption spectrum. We conclude that metamorphic QDs have a low amount of interface-related defects close to the optically active region and charge carriers can be effectively collected into InAs QDs.

Brasil, Argentina e América do Sul

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Paulo Nogueira Batista Jr.

2005-12-01

Full Text Available ESTE trabalho discute alguns aspectos da evolução econômica recente do Brasil, da Argentina e de outros países da América do Sul. Tendências econômicas e intelectuais perigosas, tais como a "globalização", o chamado Consenso de Washington, a dolarização e as negociações da Alca (Área de Livre Comércio das Américas, perderam ímpeto e a América do Sul está se movendo gradualmente na direção de um posicionamento mais independente na condução das suas política econômicas e internacionais. As mudanças foram muito mais significativas na Argentina do que no Brasil e isso se tornou fonte de alguma tensão entre os dois principais países sul-americanos. Não obstante, uma aliança estratégica entre Argentina e Brasil continua sendo a pedra angular da integração da América do Sul.THIS PAPER discusses some aspects of the recent economic evolution of Brazil, Argentina and other South American countries. Dangerous economic and intellectual trends, such as "globalization", the so-called Washington Consensus, dollarization, and FTAA (Free Trade Area of the Americas negotiations, have lost momentum and South America is moving gradually towards a more independent stance in the conduct of its economic and foreign policies. Changes have been much more significant in Argentina than in Brazil and this has become a source of some tension between the two major South American countries. Nevertheless, a strategic alliance between Argentina and Brazil remains the corner stone of South American integration.

LAS ESPECIES DE MUHLENBERGIA (POACEAE: CHLORIDOIDEAE DE ARGENTINA

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Peterson Paul

2011-06-01

Full Text Available Se presenta un estudio taxonómico de las especies nativas argentinas del géneroMuhlenbergia, basado en el análisis de los especímenes depositados en 48 herbarios.Se analizan diversos aspectos relativos a la clasifi cación, la nomenclatura y lavariación morfológica de los caracteres. Muhlenbergia está representado enArgentina por 18 especies nativas. Se proporcionan claves para reconocer lasespecies presentes en el país, así como también descripciones de éstas, sinónimos,ilustraciones, distribución geográfica y algunos comentarios morfológicos yecológicos. Muhlenbergia breviaristata (Hack. Parodi y Muhlenbergia holwayorumHitchc., se reducen como sinónimos del híbrido Muhlenbergia angustata (J. PreslKunth × M. rigida (Kunth Kunth. Muhlenbergia diversiglumis Trin. se cita porprimera vez para la Argentina. Por otra parte, las especies Muhlenbergia tenella(Kunth Trin. y Muhlenbergia tenuissima (J. Presl Kunth se excluyen de la fl orade Argentina.

Petrological evolution of subducted rodingite from seafloor metamorphism to dehydration of enclosing antigorite-serpentinite (Cerro del Almirez massif, southern Spain)

Science.gov (United States)

Laborda-López, Casto; López Sánchez-Vizcaíno, Vicente; Marchesi, Claudio; Gómez-Pugnaire, María Teresa; Garrido, Carlos J.; Jabaloy-Sánchez, Antonio; Padrón-Navarta, José Alberto

2016-04-01

Rodingites are common rocks associated with serpentinites in exhumed terrains that experienced subduction and high pressure metamorphism. However, the response of these rocks to devolatilization and redox reactions in subduction settings is not well constrained. In the Cerro del Almirez ultramafic massif (southern Spain) rodingites constitute about 1-2% of the total volume of exposed rocks. Metarodingites are enclosed in antigorite-serpentinite and chlorite-harzburgite separated by a transitional zone that represents the front of prograde serpentinite-dehydration in a paleo-subduction setting (Padrón-Navarta et al., 2011). Metarodingites occur as boudin lenses, 1 to 20 m in length and 30 cm to 2 m in thickness. During serpentinization of peridotite host rocks, dolerites and basalts precursor of rodingites underwent intense seafloor metasomatism, causing the enrichment in Ca and remobilization of Na and K. Subsequent metamorphism during subduction transformed the original igneous and seafloor metamorphic mineralogy into an assemblage of garnet (Ti-rich hydrogrossular), diopside, chlorite, and epidote. During prograde metamorphism, garnet composition changed towards higher andradite contents. High-pressure transformation of enclosing antigorite-serpentinite to chlorite-harzburgite released fluids which induced breakdown of garnet to epidote in metarodingites. Ti liberation by this latter reaction produced abundant titanite. Released fluids also triggered the formation of amphibole by alkalis addition. Highly recrystallized metarodingites in chlorite-harzburgite present a new generation of idiomorphic garnet with composition equal to 10-30% pyrope, 30-40% grossular and 35-55% almandine + spessartine. This garnet has titanite inclusions in the core and rutile inclusions in the rim. The contact between metarodingites and ultramafic rocks consists of a metasomatic zone (blackwall) with variable thickness (7 to 40 cm) constituted by chlorite, diopside, and titanite

Reaction induced nucleation and growth v. grain coarsening in contact metamorphic, impure carbonates

DEFF Research Database (Denmark)

Berger, Alfons; Brodhag, Sabine; Herwegh, Marco

2010-01-01

aureole of the Adamello pluton (N-Italy). As a function of increasing distance from the pluton contact, the investigated samples have peak metamorphic temperatures ranging from the stability field of diopside/tremolite down to diagenetic conditions. All samples consist of calcite as the dominant matrix...

Sc, Y, La-Lu. Rare earth elements. Vol. A 6a. Y, La, and the lanthanoids. Geochemistry: Sedimentary cycle. Metamorphic cycle. 8. rev. ed

Energy Technology Data Exchange (ETDEWEB)

Ditz, R; Sarbas, B; Schubert, P; Toepper, W

1988-01-01

The present volume 'Rare Earth Elements' A 6a describes origin, mode of occurrence, and behavior of Y and RE elements in the sedimentary and metamorphic cycles, and completes the series of volumes describing cosmo- and geochemistry of these elements. In the chapter 'Sedimentary Cycle', the behavior of Y and RE during the weathering process is first outlined under both marine and terrestrial conditions, including a short compilation for migration and precipitation in surficial weathering and oxidation zones. The main part of the chapter treats, in addition to the mode of occurrence, predominantly the distribution of Y and RE in the different types of sedimentary rocks in relation to genetic processes (comprising physical and/or spatial factors such as geological age of the deposition). A concluding part gives a description of mobilization, migration, and precipitation of Y and RE during the diagenetic transformation of sediments, especially in relation to the various types of ferromanganese concretions. In the chapter 'Metamorphic Cycle', the first, extensive part gives examples of mode of occurrence and behavior of Y and RE during both the contact-metamorphic and prograde and retrograde regional-metamorphic processes affecting sedimentary and igeneous source rocks. The second part briefly describes behaviour of Y and RE during ultrametamorphism of metamorphic rocks, and during metamorphic processes in connection with special types of geologic events (as, e.g., subduction of crustal material into the earth's mantle and impact of extraterrestrial material). (orig.) With 4 figs.

Biodiversity information system of the national parks administration of Argentina

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Leonidas Lizarraga

2014-06-01

Full Text Available Introduction The Biodiversity Information System (BIS of the National Parks Administration of Argentina (NPA was launched in 2002, with the support of the Global Environmental Fund (GEF through the Biodiversity Conservation Project in Argentina. The BIS consists of a set of thematic databases and Geographic Information System (GIS set to support management decisions, and to provide information to the general public on the national protected areas of Argentina. Currently, the BIS-NPA progr...

Update on women in physics in Argentina

Science.gov (United States)

Brudny, Vera; Lagorio, Cecilia; Frechero, Marisa; Tamarit, Francisco

2013-03-01

Data collected 10 years ago in Argentina concluded that women in physics were underrepresented in many instances and that a "crystal ceiling" was firmly in place. We have collected updated data for several indicators and compared them with those obtained 10 years ago. Although there is not a clear conclusion to be drawn from this comparison, we try to explain the results within the framework of the changes in scientific policies in Argentina.

Transnational Crime Fictions and Argentina's Criminal State

OpenAIRE

Caballero, Juan

2013-01-01

My dissertation, titled "Transnational Crime Fictions and Argentina's Criminal State," proposes a new understanding of the dictatorship novels of Ricardo Piglia, Juan José Saer, and Manuel Puig grounded in their shared appropriation from popular crime fiction. Across the 1940's, 50's, and 60's, a wide range of popular crime fiction was translated, written, theorized, printed and reprinted in Argentina, and these popular genres grew steadily in readership, visibility, and cultural legitimacy....

China, Argentina agree to further strategic ties

Institute of Scientific and Technical Information of China (English)

2011-01-01

According to Xinhua,China and Argentina have agreed to further enhance mutual trust and their strategic partnership as the two emerging economies are playing an increasingly important role in the world arena.“China will work with Argentina to strengthen strategic mutual trust,expand cooperation and coordination within multilateral frameworks in order to promote bilateral ties and benefit the two peoples,” Vice President Xi Jinping told Argentine Foreign Minister Hector Timerman on September 9.

Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt

International Nuclear Information System (INIS)

Abbady, Adel G.E.; El-Arabi, A.M.; Abbady, A.

2006-01-01

Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 μW m -3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 μW m -3 (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites

Heat production rate from radioactive elements in igneous and metamorphic rocks in eastern desert, Egypt

International Nuclear Information System (INIS)

Abbady, A G.E.; Arabi, A.M.; Abbay, A.

2005-01-01

Radioactive heat - production data of igneous and metamorphic rocks cropping out from the eastern desert are presented. Samples were analysed using low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 Μ Wm-3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite) to 0.91 (metagabroo) Μ W.m-3. The contribution due to U is about (51%), whereas that of Th (31%) and (18%) by K. The corresponding values in igneous rocks are 76%: 19%: 5%, respectively. The calculated values showed good agreement with global values expect in some areas contained granite rocks

Alkali control of high-grade metamorphism and granitization

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Oleg G. Safonov

2014-09-01

Full Text Available We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is implemented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes: rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s.

All projects related to Argentina | Page 7 | IDRC - International ...

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

Region: Americas, Argentina, South America. Program: Climate Change. Total Funding: CA$ 995,000.00. Youth Smoking in Stressed Environments : Determinants and Resiliency (Argentina, Colombia, Palestine). Project. Numerous studies have shown that the earlier an individual starts smoking, the harder it is to give it up.

Nuclear Energy Stakeholders in Argentina

International Nuclear Information System (INIS)

Gadano, Julian

2017-01-01

Mr Gadano, Undersecretary for Nuclear Energy, Argentina spoke from the perspective of a country looking forward to becoming a member of the NEA. He reviewed the place of nuclear energy in his country's energy mix and called attention to its role in positively addressing the global challenges of climate change and energy security. Mr Gadano also described the federal system which governs Argentina. Drawing on his expertise as a lawmaker and nuclear regulator but also as an academic sociologist, he stressed that reaching agreement on siting initiatives for example requires a sustainable relation with stakeholders, including regional governments. This is important because in the end, 'the best project is the one you can finish'

Argentina set for privatization

International Nuclear Information System (INIS)

Chynoweth, E.

1992-01-01

Buyers are lining up for Argentina's two big state-controlled petrochemical groups, Buenos Aires-based Petroquimica General Mosconi (PGM) and Petroquimica Bahia Blance (PBB). However, feedstock supply contracts with government-owned oil group Yacientos Petroliferos Fiscales (YPG) and gas group Gas del Estado hold the key to both sales. Shell Compania Argentina Petroleo SA (CAPSA), Perez Companc, and Global Petroleum have already bought PGM tender documentation. Shell says it will bid for PGM if the feedstock contract with YPF is acceptable. In addition to price and volume, Shell says the length is critical; it wants a 15-year deal, but would settle for 11. YPF initially sought a five-year contract. PGM, which produces 300,000 m.t./year of aromatics, plus oxo alcohols, methanol, and methyl tert-butyl ether, has sales of $150 million/year

The other immigration to Argentina: the case of Adolf Eichmann

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Christian Cwik

2014-01-01

Full Text Available Adolf Eichmann llegó a la Argentina como otros 500 Nazis forajidos a través de una red de traficantes ilegales de migrantes entre 1945 y 1955. Esta red fue el resuldado del interés de la República de Argentina, la Cruz Roja, la Caritas y el Vaticano por un lado y por el otro los delincuentes. Eichmann la cara de la ‘banalidad del mal’, como Hannah Arendt escribió en su libro “Eichmann en Jerusalén: un estudio sobre la banalidad del mal”(2ª. edición, traducción de Carlos Ribalta, Barcelona, Lumen, 1999 tuvo bastantes problemas para integrarse en la sociedad argentina y por ende, fracasó. Adolf Eichmann nacido en 1906 en Solingen/Alemania personificó un caractér típico de la sociedad en la posguerra austriaca-alemana, lo que hizo que fracasara en su vida laboral varias veces durante los veintes y los inicios de los treinta del siglo XX.Palabras Clave: Adolf Eichmann;  Holocausto; Tráfico Ilegal de Migrantes; Inmigración en Argentina; Peronismo; Tribunales Internacionales. La otra inmigración a Argentina: El caso de Adolf EichmannAbstractAdolf Eichmann arrived to Argentina along with other 500 runaway Nazis thorugh a smuggling network between 1945 and 1955. This network was the result of the interest shown by the The Republic of Argentina, the Red Cross, Caritas and the Vatican in one hand; in the other, the criminals of war. Eichmann, the face of Hanna Arendt’s t “Banality of Evil” had numerous troubles to integrate to argentinian society, failing as a result.Adolf Eichmann, born in 1906 in Solingen, Germany, personified a typical Austrian-german postwar character, a fact that conduced to his laboral failure in the twentys and early thirties of the twentieth century.Keywords:Adolf Eichmann; Holocaust; Nazi Criminals; Trafficking of migrants; Post War Period; Immigration to Argentina; Peronism; Mossad; International Tribunal. 

Mineral chemistry of garnet in pegmatite and metamorphic rocks in the Hamedan area

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Ahmad Ahmadi Khalaji

2015-10-01

Full Text Available Introduction The area of this study is located near Hamadan within the Sanandaj - Sirjan tectonic zone. In the Hamadan area, consisting mainly of Mesozoic plutonic and metamorphic rocks, aplites and pegmatites locally contain garnets.(Baharifar et al., 2004, Amidi and Majidi, 1977; Torkian, 1995. Garnet-bearing schists and hornfelses in the area are products of regional metamorphism shown by slate and phyllite (Baharifar, 2004. In this investigation the distribution of elements in garnet in different rock type was studied to determine their mineral types and conditions of formation. Garnet samples from igneous and metamorphic rocks were analyzed by electron microprobe (EMPA, the results of which are presented in this article. Materials and methods Thirty-five samples were selected for thin section preparation and twenty thin-polished sections were prepared for mineralogical and microprobe analysis. Thin sections of garnet-bearing igneous (pegmatite and metamorphic rocks (schist and hornfels were studied by polarizing microscope. Chemical analysis was performed on the garnets (38 points using a Caimeca SX100 electron microprobe at an acceleration voltage of 15 kV and electric current of 15 nA in the Mineral Processing Research Center, Iran. Separation of iron (II and Fe (III was calculated by Droop’s method (1987 and the structural formulas of the garnets were calculated using 24 oxygens to determine the relative proportions of the end-members using the mineral spreadsheet software of Preston and Still (2001. Results Based on the analyses, almandine (Fe - Al garnet and spessartine (Mn - Al garnet are the principal types of the (Kamari metamorphic and (Abaro pegmatitic garnets, that belong to the well-known pyralspite garnet group. Chemical zoning patterns of the garnets in the metamorphic rocks (schists differ from those in the igneous rocks (pegmatite, showing different compositions from core to rim. Petrographic evidence such as: co

El IDRC en Argentina

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

comercio capaces de sostener el crecimiento y reducir la pobreza. ... Rosario, en Argentina, se ha convertido en un ejemplo internacional para la agricultura urbana gracias a la ... para evaluar los riesgos y beneficios de esta tecnología para ...

New evidence for an old idea: Geochronological constraints for a paired metamorphic belt in the central European Variscides

Science.gov (United States)

Will, T. M.; Schmädicke, E.; Ling, X.-X.; Li, X.-H.; Li, Q.-L.

2018-03-01

New geochronological data reveal a prolonged tectonothermal evolution of the Variscan Odenwald-Spessart basement, being part of the Mid-German Crystalline Zone in central Europe. We report the results from (i) secondary ion mass spectrometry (SIMS) U-Pb dating of zircon, rutile and monazite, (ii) SIMS zircon oxygen isotope analyses, (iii) laser ablation-multicollector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) zircon Lu-Hf isotope analyses and, (iv) LA-ICPMS zircon and rutile trace element data for a suite of metamorphic rocks (five amphibolite- and eclogite-facies mafic meta-igneous rocks and one granulite-facies paragneiss). The protoliths of the mafic rocks formed from juvenile as well as depleted mantle sources in distinct tectonic environments at different times. Magmatism took place at a divergent oceanic margin (possibly in a back-arc setting) at 460 Ma, in an intraoceanic basin at ca. 445 Ma and at a continental margin at 329 Ma. Regardless of lithology, zircon in eclogite, amphibolite and high-temperature paragneiss provide almost identical Carboniferous ages of 333.7 ± 4.1 Ma (eclogite), 329.1 ± 1.8 to 328.4 ± 8.9 Ma (amphibolite), and 334.0 ± 2.0 Ma (paragneiss), respectively. Rutile yielded ages of 328.6 ± 4.7 and 321.4 ± 7.0 Ma in eclogite and amphibolite, and monazite in high-temperature paragneiss grew at 330.1 ± 2.4 Ma (all ages are quoted at the 2σ level). The data constrain coeval high-pressure eclogite- and high-temperature granulite-facies metamorphism of the Odenwald-Spessart basement at ca. 330 Ma. Amphibolite-facies conditions were attained shortly afterwards. The lower plate eclogite formed in a fossil subduction zone and the upper plate high-temperature, low-pressure rocks are the remains of an eroded Carboniferous magmatic arc. The close proximity of tectonically juxtaposed units of such radically different metamorphic conditions and thermal gradients is characteristic for a paired metamorphic belt sensu Miyashiro

Activities with Argentina

International Nuclear Information System (INIS)

1999-01-01

In 1989, the US Department of Energy (DOE) responded to the need to redirect resources from weapons production to environmental restoration and waste management by establishing the Office of Environmental Management (EM) and delegated to this office the responsibility of cleaning up the US nuclear weapons complex. Now in its eight year, EM's mission has three central facets: (1) to assess, remediate, and monitor contaminated sites and facilities; (2) to store, treat, and dispose of waste from past and current operations; and (3) to develop and implement innovative technologies for environmental cleanup. To this end, EM has established domestic and international cooperative technology development programs, including one with the Republic of Argentina. Cooperating with Argentine scientific institutes and industries meets US cleanup objectives by: (1) identifying and accessing Argentine EM-related technologies, thereby leveraging investments and providing cost-savings; (2) improving access to technical information, scientific expertise, and technologies applicable to EM needs; and (3) fostering the development of innovative environmental technologies by increasing US private sector opportunities in Argentina in EM-related areas

Preliminary isotopic data from some amphibolites of the metamorphic basement of the Colombian Central Cordillera

International Nuclear Information System (INIS)

Correa M, Ana Maria; Martens K, Uwe; Ordonez C, Oswaldo; Pimentel, Marcio M; Restrepo A, Jorge Julian

2001-01-01

Various amphibolite bodies are exposed in the Antioquia Department, Colombia, mainly around the cities of Medellin and El Retiro. Two types of amphibolites occur in the study area; the first one is considered as part of an ophiolite complex and the second one correspond to amphibolites associated to metasediments from the basement of the Colombian Central Cordillera. The present work refers to these last ones. The relationships between amphibolite bodies and other lythological units are the following ones: Intercalation of amphibolites layers with metasediments in the unit migmatites and granulites of El Retiro. The Medellin amphibolites are conformably overlaid by the paragneisses of Las Penas. The granodiorite body represented by the Antioquian Batolith is intrusive in the metamorphic rocks and the Medellin Dunites unit is in thrust fault contact with Medellin amphibolites. These amphibolites have been studied by Botero (1963), Gonzalez (1976 and 1980), Restrepo and Toussaint (1984), Ardila (1986), Restrepo (1986), Rendon (1999) and, Correa and Martens (2000). Available radiometric ages on the amphibolites come from former works by Restrepo y Toussaint (1978), Restrepo et al. (1991) that presented K-Ar ages in amphiboles and a Rb-Sr isochron which yielded a Cretaceous age that they interpreted as a metamorphic age. This work presents new evidences, obtained from field work, petrography, rock geochemistry and specially the first isotopic data on these amphibolites from the Central Cordillera Metamorphic Basement (au)

The next chapter in experimental petrology: Metamorphic dehydration of polycrystalline gypsum captured in 3D microtomographic time series datasets

Science.gov (United States)

Bedford, John; Fusseis, Florian; Leclere, Henry; Wheeler, John; Faulkner, Dan

2016-04-01

Nucleation and growth of new minerals in response to disequilibrium is the most fundamental metamorphic process. However, our current kinetic models of metamorphic reactions are largely based on inference from fossil mineral assemblages, rather than from direct observation. The experimental investigation of metamorphism has also been limited, typically to concealed vessels that restrict the possibility of direct microstructural monitoring. Here we present one of the first time series datasets that captures a metamorphic reaction, dehydration of polycrystalline gypsum to form hemihydrate, in a series of three dimensional x-ray microtomographic datasets. We achieved this by installing an x-ray transparent hydrothermal cell (Fusseis et al., 2014, J. Synchrotron Rad. 21, 251-253) in the microtomography beamline 2BM at the Advanced Photon Source (USA). In the cell, we heated a millimetre-sized sample of Volterra Alabaster to 388 K while applying an effective pressure of 5 MPa. Using hard x-rays that penetrate the pressure vessel, we imaged the specimen 40 times while it reacted for approximately 10 hours. Each microtomographic dataset was acquired in 300 seconds without interrupting the reaction. Our absorption microtomographic data have a voxel size of 1.3 μm, which suffices to analyse the reaction progress in 4D. Gypsum can clearly be distinguished from hemihydrate and pores, which form due to the large negative solid volume change. On the resolved scale, the first hemihydrate needles appear after about 2 hours. Our data allow tracking of individual needles throughout the entire experiment. We quantified their growth rates by measuring their circumference. While individual grains grow at different rates, they all start slowly during the initial nucleation stage, then accelerate and grow steadily between about 200 and 400 minutes before reaction rate decelerates again. Hemihydrate needles are surrounded by porous haloes, which grow with the needles, link up and

Electrical and structural characteristics of metamorphic In0.38Al0.62As/In0.37Ga0.63As/In0.38Al0.62As HEMT nanoheterostructures

International Nuclear Information System (INIS)

Galiev, G. B.; Klimov, E. A.; Klochkov, A. N.; Maltsev, P. P.; Pushkarev, S. S.; Zhigalina, O. M.; Imamov, R. M.; Kuskova, A. N.; Khmelenin, D. N.

2013-01-01

The influence of the metamorphic buffer design and epitaxial growth conditions on the electrical and structural characteristics of metamorphic In 0.38 Al 0.62 As/In 0.37 Ga 0.63 As/In 0.38 Al 0.62 As high electron mobility transistor (MHEMT) nanoheterostructures has been investigated. The samples were grown on GaAs(100) substrates by molecular beam epitaxy. The active regions of the nanoheterostructures are identical, while the metamorphic buffer In x Al 1−x As is formed with a linear or stepwise (by Δ x = 0.05) increase in the indium content over depth. It is found that MHEMT nanoheterostructures with a step metamorphic buffer have fewer defects and possess higher values of two-dimensional electron gas mobility at T = 77 K. The structures of the active region and metamorphic buffer have been thoroughly studied by transmission electron microscopy. It is shown that the relaxation of metamorphic buffer in the heterostructures under consideration is accompanied by the formation of structural defects of the following types: dislocations, microtwins, stacking faults, and wurtzite phase inclusions several nanometers in size

Metaultramafic schists and dismembered ophiolites of the Ashe Metamorphic Suite of northwestern North Carolina, USA

Science.gov (United States)

Raymond, Loren A.; Merschat, Arthur J.; Vance, R. Kelly

2016-01-01

Metaultramafic rocks (MUR) in the Ashe Metamorphic Suite (AMS) of northwestern North Carolina include quartz ± feldspar-bearing QF-amphibolites and quartz-deficient, locally talc-, chlorite-, and/or Mg-amphibole-bearing TC-amphibolites. Some workers divide TC-amphibolites into Todd and Edmonds types, based on mineral and geochemical differences, and we provisionally add a third type – olivine ± pyroxene-rich, Rich Mountain-type rocks. Regionally, MUR bodies range from equant, Rich Mountain- to highly elongate, Todd-TC-amphibolite-type bodies. The MURs exhibit three to five mineral associations containing assemblages with olivine, anthophyllitic amphibole, Mg-hornblende, Mg-actinolite, cummingtonite, and serpentine representing decreasing eclogite to greenschist facies grades of metamorphism over time. MUR protoliths are difficult to determine. Southwestern MUR bodies have remnant olivine ± pyroxene-rich assemblages representing ultrabasic-basic, dunite-peridotite-pyroxenite protoliths. Northeastern TC-amphibolite MURs contain hornblende and actinolitic amphiboles plus chlorites – aluminous and calcic assemblages suggesting to some that metasomatism of basic, QF-amphibolites yields all TC-amphibolites. Yet MgO-CaO-Al2O3 and trace element chemistries of many TC-amphibolites resemble compositions of plagioclase peridotites. We show that a few AMS TC-amphibolites had basaltic/gabbroic protoliths, while presenting arguments opposing application of the metasomatic hypothesis to all TC-amphibolites. We establish that MUR bodies are petrologically heterolithic and that TC-amphibolites are in contact with many rock types; that those with high Cr, Ni, and Mg have olivine- or pyroxene-dominated protoliths; that most exhibit three or more metamorphic mineral associations; and that contacts thought to be metasomatic are structural. Clearly, different MUR bodies have different chemistries representing various protoliths, and have different mineral assemblages, reflecting

Optimization of structural and growth parameters of metamorphic InGaAs photovoltaic converters grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Rybalchenko, D. V.; Mintairov, S. A.; Salii, R. A.; Shvarts, M. Z.; Timoshina, N. Kh.; Kalyuzhnyy, N. A., E-mail: nickk@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

2017-01-15

Metamorphic Ga{sub 0.76}In{sub 0.24}As heterostructures for photovoltaic converters are grown by the MOCVD (metal–organic chemical vapor deposition) technique. It is found that, due to the valence-band offset at the p-In{sub 0.24}Al{sub 0.76}As/p-In{sub 0.24}Ga{sub 0.76}As (wide-gap window/emitter) heterointerface, a potential barrier for holes arises as a result of a low carrier concentration in the wide-gap material. The use of an InAlGaAs solid solution with an Al content lower than 40% makes it possible to raise the hole concentration in the widegap window up ~9 × 10{sup 18} cm{sup –3} and completely remove the potential barrier, thereby reducing the series resistance of the device. The parameters of an GaInAs metamorphic buffer layer with a stepwise In content profile are calculated and its epitaxial growth conditions are optimized, which improves carrier collection from the n-GaInAs base region and provides a quantum efficiency of 83% at a wavelength of 1064 nm. Optimization of the metamorphic heterostructure of the photovoltaic converter results in that its conversion efficiency for laser light with a wavelength of 1064 nm is 38.5%.

Unified Singularity Modeling and Reconfiguration of 3rTPS Metamorphic Parallel Mechanisms with Parallel Constraint Screws

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Yufeng Zhuang

2015-01-01

Full Text Available This paper presents a unified singularity modeling and reconfiguration analysis of variable topologies of a class of metamorphic parallel mechanisms with parallel constraint screws. The new parallel mechanisms consist of three reconfigurable rTPS limbs that have two working phases stemming from the reconfigurable Hooke (rT joint. While one phase has full mobility, the other supplies a constraint force to the platform. Based on these, the platform constraint screw systems show that the new metamorphic parallel mechanisms have four topologies by altering the limb phases with mobility change among 1R2T (one rotation with two translations, 2R2T, and 3R2T and mobility 6. Geometric conditions of the mechanism design are investigated with some special topologies illustrated considering the limb arrangement. Following this and the actuation scheme analysis, a unified Jacobian matrix is formed using screw theory to include the change between geometric constraints and actuation constraints in the topology reconfiguration. Various singular configurations are identified by analyzing screw dependency in the Jacobian matrix. The work in this paper provides basis for singularity-free workspace analysis and optimal design of the class of metamorphic parallel mechanisms with parallel constraint screws which shows simple geometric constraints with potential simple kinematics and dynamics properties.

Vacuna contra la fiebre hemorrágica argentina Candid#1 producida en la Argentina: Inmunogenicidad y seguridad

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Delia A. Enria

2010-06-01

Full Text Available Se realizó un estudio clínico en 946 voluntarios humanos sanos, donde se comparó la vacuna Candid#1 producida en Argentina con la elaborada en EE.UU., que había sido utilizada en estudios previos. Como objetivo primario se evaluó la equivalencia en la eficacia utilizando como marcador subrogante a la inmunogenicidad medida por detección de anticuerpos neutralizantes. Como objetivo secundario se evaluó la equivalencia en inocuidad comparando las tasas de reacciones adversas. Ambas vacunas mostraron una tasa equivalente de inmunogenicidad ligeramente superior al 95.5%, que es la eficacia estimada para Candid #1 en estudios previos. No se observaron eventos adversos graves relacionados con la vacuna. Los eventos adversos generales considerados relacionados fueron de escasa significación clínica y de resolución espontánea o con tratamiento sintomático; se presentaron en los receptores de ambas vacunas en tasas equivalentes (29.9% para la vacuna fabricada en la Argentina y 35.0% para la fabricada en EE.UU., e incluyeron: cefalea, decaimiento, mialgias, plaquetopenia leve (< 150 000 plaquetas/mm³, náuseas y/o vómitos, leucopenia leve (< 4 000 blancos/mm³, fiebre, dolor retroocular, mareos, microhematuria, lumbalgia y exantema. Estos resultados indican que la vacuna Candid #1 elaborada en la Argentina es equivalente a la elaborada en los EE.UU. Este estudio permitió el registro del biológico producido en la Argentina ante la autoridad regulatoria del país (ANMAT.

A Argentina depois da conversibilidade: um caso de novo-desenvolvimentismo?

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André Moreira Cunha

2009-03-01

Full Text Available This paper analyses the economic recovery in post-Convertibility Argentina. We try to identify if there are evidences to support the suggestion that Argentina could be an example of the so-called "new developmentalism".

Overview and perspectives for Open Access development in Argentina

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Sandra Miguel

2013-04-01

Full Text Available This paper provides an overview and perspectives for development of the Open Access movement in Argentina, within the global and regional (Latin American context. It outlines the evolution and current state of initiatives around the two main approaches to Open Access, the golden and green roads. The main Open Access policies and support of OA movement by governments in Latin American region, and particularly in Argentina, are highlighted, while recent studies on publishing practices and authors’ positions regarding Open Access are presented. The paper concludes that the prospects for development of OA in Argentina, both through golden and green roads are favorable, with their strengths and shortcomings

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

Science.gov (United States)

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

Radiation vulcanization in Argentina

International Nuclear Information System (INIS)

Ferenaz, Guillermo W.; Smolko, Eduardo E.

1999-01-01

The possibilities of using in Argentina the radiation process to vulcanize natural latex are analyzed. Experimental studies to define the irradiation conditions have been carried out and the preliminary elaboration of an irradiation device that includes the chemical reactor has been started. (author)

78 FR 46610 - Lemon Juice From Argentina and Mexico

Science.gov (United States)

2013-08-01

... Argentina and Mexico Determination On the basis of the record \\1\\ developed in the subject five-year reviews... determines that termination of the suspended antidumping duty investigation on lemon juice from Mexico would...), entitled Lemon Juice from Argentina and Mexico: Investigation Nos. 731-TA-1105-1106 (Review). By order of...

78 FR 47006 - Lemon Juice From Argentina and Mexico

Science.gov (United States)

2013-08-02

... Argentina and Mexico Determination On the basis of the record \\1\\ developed in the subject five-year reviews... determines that termination of the suspended antidumping duty investigation on lemon juice from Mexico would...), entitled Lemon Juice from Argentina and Mexico: Investigation Nos. 731-TA-1105-1106 (Review). By order of...

Update on women in physics in Argentina

OpenAIRE

Brudny, Vera Leonor; Lagorio, Cecilia; Frechero, Marisa Alejandra; Tamarit, Francisco

2016-01-01

Data collected 10 years ago in Argentina concluded that women in physics were underrepresented in many instances and that a “crystal ceiling” was firmly in place. We have collected updated data for several indicators and compared them with those obtained 10 years ago. Although there is not a clear conclusion to be drawn from this comparison, we try to explain the results within the framework of the changes in scientific policies in Argentina. Fil: Brudny, Vera Leonor. Universidad de Buenos...

Education and Dictatorship in Argentina 1976-1983

OpenAIRE

Kaufmann, Carolina

2000-01-01

Este artículo señala aspectos generales del autodenominado “Proceso” acaecido en Argentina (1976-1983). Se ofrecen evidencias de censura e imposición autoritaria en el sistema educativo. Asimismo, se explicitan elementos constitutivos de la educación personalizada perennialista y de la pedagogía de los valores que fue adoptada durante aquellos años. This article indicates general aspects of the self-styled "Process" occurred in Argentina (1976-1983). Evidence of censorship and authoritar...

Bolivia's gas heads for Brazil as Argentina waits - and watches

International Nuclear Information System (INIS)

Knight, P.

1998-01-01

The first 1,800 km stretch of a 3,400 km natural gas pipeline from Bolivia to Brazil will start operating in December. First planned 50 years ago, the pipeline has long been expected to result in an immediate surge of gas use in Brazil. However, impending deep recession in Brazil makes this prospect less likely despite the power shortages which indicate the need for considerable gas imports. Initially, most Bolivian gas will flow through Brazil to Argentina. But gas production is expanding rapidly in Argentina and the supply contract with Bolivia ends in 1999. Plans are well advanced to build two gas lines into the south of the Brazil from Argentina. Ultimately, it is anticipated that Argentina, which has abundant reserves and a virtually saturated domestic market, will become the principal source of natural gas for Brazil. (UK)

1 Estudio Sectorial Sector lácteo de Argentina

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

Resumen: La producción de leche y productos lácteos conforma en Argentina un importante complejo productivo, de larga trayectoria histórica y gran impacto económico y social. En Argentina, esta industria conforma un oligopolio diferenciado en el que coexisten unas pocas grandes empresas nacionales y ...

Cristal size distribution in metamorphic rocks: an example for the relationship between nucleation and growth rates with overstepping

International Nuclear Information System (INIS)

Homan, S. M.

2003-01-01

Crystal size distribution in metamorphic rocks provide fundamental information about crystal nucleation and growth rate, growth time and the degree of overstepping. Crystal size distribution data for garnet, saluretil, keynote, and and alusite crystals from the aureole demonstrate that the earliest formed of this minerals, garnet, has the highest population density and the shortest growth time. The last formed mineral, and alusite, has the lowest population density and longest growth time. keynote and saluretil have the similar population density and growth times intermediate between those of overstepping on the nucleation and growth rates of minerals during metamorphism

CALYPTRANTHES TRICONA (MYRTACEAE, NUEVA CITA PARA LA FLORA ARGENTINA

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Sara G. Tressens

1996-01-01

Full Text Available Calyptranthes tricona D. Legrand (Myrtaceae es reportada por primera vez para la Argentina.  Se incluyen una descripción y una ilustración. Se presenta un clave para la identificación de las especies argentinas de Calyptranthes se da. Se discuten algunas observaciones sobre la nomenclatura C.concinna DC.

The text of the agreement of 22 July 1977 between Argentina and the Agency for the application of safeguards in connection with a co-operation agreement between Argentina and Canada

International Nuclear Information System (INIS)

1995-01-01

The Agreement between the Republic of Argentina, the Federative Republic of Brazil, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials and the International Atomic Energy Agency for the Application of Safeguards came into force on 4 March 1994. As a result of the coming into force of the aforesaid Agreement for Argentina, the application of safeguards under the Agreement of 22 July 1977 between Argentina and the IAEA for the application of safeguards in connection with a co-operation agreement between Argentina and Canada has been suspended

Panorama de la familia Asteraceae (= Compositae en la Republica Argentina An overview of the plant family Asteraceae ( = Compositae in Argentina

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Liliana Katinas

2007-07-01

Full Text Available Se presenta un panorama de la familia Asteraceae en la República Argentina , que incluye una breve historia taxonómica, datos numéricos de tribus, géneros y especies, ejemplos de endemismos y daptaciones ecológicas y una reseña sobre la hipótesis del origen de la familia en Patagonia. En la Argentina, las asteráceas representan la familia más numerosa con 227 géneros (cinco son endémicos y ca. 1400 especies (92 son adventicias y 382 son endémicas. En términos de taxones nativos, se hallan representadas en nuestro país todas las tribus de Asteraceae excepto Inuleae (sensu Bremer. Las tribus Arctoteae y Calenduleae están representadas por taxones adventicios exclusivamente y Cardueae posee sólo una especie nativa. Barnadesieae y Mutisieae son las únicas tribus con géneros endémicos de Argentina y también presentan el porcentaje más alto de géneros y especies en el país en comparación con el resto de las tribus. El mayor número de especies nativas, endémicas y no endémicas, se da en las provincias fitogeográficas Altoandina y Patagónica. La tribu más representada en número de géneros es Heliantheae, y en número de especies nativas es Senecioneae.An overview of the family Asteraceae in Argentina that includes a brief taxonomic history, numerical data of tribes, genera and species, examples of endemisms and ecological adaptations, and a discussion on the hypothesis on the origin of the family in Patagonia is given. Asteraceae is the most numerous family in Argentina , with 227 genera (five are endemic and ca. 1400 species (92 are adventitious and 382 are endemic. In relation to the native taxa, all tribes of Asteraceae occur in Argentina excepting Inuleae (sensu Bremer. Tribes Arctoteae and Calenduleae are represented exclusively by adventitious taxa, and Cardueae has only one native species. Barnadesieae and Mutisieae are the only tribes with endemic genera in Argentina and they also present the highest percentage of

Anatexis and metamorphism in tectonically thickened continental crust exemplified by the Sevier hinterland, western North America

Science.gov (United States)

Patino Douce, Alberto E.; Humphreys, Eugene D.; Johnston, A. Dana

1990-01-01

This paper presents a thermal and petrologic model of anatexis and metamorphism in regions of crustal thickening exemplified by the Sevier hinterland in western North America, and uses the model to examine the geological and physical processes leading to crustally derived magmatism. The results of numerical experiments show that anatexis was an inevitable end-product of Barrovian metamorphism in the thickened crust of the late Mesozoic Sevier orogenic belt and that the advection of heat across the lithosphere, in the form of mantle-derived mafic magmas, was not required for melting of metasedimentary rocks. It is suggested that, in the Sevier belt, as in other intracontinental orogenic belts, anatexis occurred in the midcrust and not at the base of the crust.

Argentina's YPF hones in on privatization

International Nuclear Information System (INIS)

Anon.

1991-01-01

This paper reports on Argentina's push to privatize and attract more foreign investment to its petroleum sector which continues to gather momentum. The Argentine government plans by year end 1992 to sell unprofitable assets of Yacimientos Petroliferos Fiscales, then sell as much as 50% of the state oil company through an international stock offering. If privatization proceeds as expected, YPF Pres. Jose Estenssoro the, the company's stock will be offered to private investors early in 1993. The company was founded in 1922. By March 1992, Argentina also will begin selling all assets of state owned Gas del Estado (GDE) through an international bidding process expected to take about 18 months

The Lost South Gobi Microcontinent: Protolith Studies of Metamorphic Tectonites and Implications for the Evolution of Continental Crust in Southeastern Mongolia

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Matthew J. Heumann

2013-08-01

Full Text Available The Central Asian Orogenic Belt, or Altaids, is an amalgamation of volcanic arcs and microcontinent blocks that records a complex late Precambrian–Mesozoic accretionary history. Although microcontinents cored by Precambrian basement are proposed to play an integral role in the accretion process, a lack of isotopic data hampers volume estimates of newly produced arc-derived versus old-cratonic crust in southeastern Mongolia. This study investigates metamorphic tectonites in southern Mongolia that have been mapped as Precambrian in age, largely on the basis of their high metamorphic grade and high strain. Here we present results from microstructural analyses and U-Pb zircon geochronology on samples from Tavan Har (44.05° N, 109.55° E and the Yagan-Onch Hayrhan metamorphic core complex (41.89° N, 104.24° E. Our results show no compelling evidence for Precambrian basement in southeastern Mongolia. Rather, the protoliths to all tectonites examined are Paleozoic–Mesozoic age rocks, formed during Devonian–Carboniferous arc magmatism and subsequent Permian–Triassic orogenesis during collision of the South Mongolia arc with the northern margin of China. These results yield important insights into the Paleozoic accretionary history of southern Mongolia, including the genesis of metamorphic and igneous basement during the Paleozoic, as well as implications for subsequent intracontinental reactivation.

Mesozoic monazite in Neoproterozoic metasediments. Evidence for low-grade metamorphism of Sinian sediments during Triassic continental collision, Liaodong Peninsula, NE China

International Nuclear Information System (INIS)

Wan Yusheng; Song Tianrui; Liu Dunyi; Yang Tiannan; Yin Xiaoyan; Zhang Qiaoda; Chen Zhenyu

2007-01-01

Sericite phyllite from the Sinian Shisanlitai Formation, Dalian area, Liaodong Peninsula, NE China, contains an assemblage of newly-formed lower-greenschist facies minerals (sericite, chlorite, Fe minerals and Ti minerals) plus aggregates of fine-grained monazite. The texture of the monazite, its mineral inclusions, and its close association with Fe oxide minerals show that it is not detrital or diagenetic, but a product of the low-grade metamorphism. SHRIMP U-Th-Pb dating of the monazite at 217±15 Ma shows that the metamorphism, and associated regional deformation and fluid flow, occurred in the Late Triassic, coeval with the waning stages of the Dabie-Sulu orogeny. The Dabie-Sulu tectonothermal event has produced both deformation and metamorphism in rocks of the eastern North China Block at least up to ∼200 km north of the main continent-continent collision zone. (author)

Argentina v globalizačních procesech

OpenAIRE

Chervets, Tamara

2009-01-01

The process of globalization is a very important issue these days. This work will describe the process of globalization in Argentina, especially its economic aspect (foreign direct investments, export and import of goods and services, migration of labor force). I will also mention the history of its development and Argentina's membership in most important international and regional organizations.

Pro-Market Educational Governance: Is Argentina a Black Swan?

Science.gov (United States)

Beech, Jason; Barrenechea, Ignacio

2011-01-01

In this article we explore ways in which pro-market discourses have been interpreted in policy initiatives in Argentina since the 1970s. Our argument is that even though pro-market discourses have guided reforms in many aspects of public policies in Argentina, the arena of education has overall been resistant to taking them up. The first part of…

Scenarios for wind power in Brazil, Argentina and Chile; Cenarios para a energia eolio eletrica no Brasil, Argentina e Chile

Energy Technology Data Exchange (ETDEWEB)

Dedecca, Joao Gorestein; Nogueira, Larissa Goncalves; Jannuzzi, Gilberto de Martino [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Energia], emails: jdedecca@fem.unicamp.br, larissa@fem.unicamp.br, januzzi@fem.unicamp.br; Gomes, Rodolfo Dourado [International Energy Initiative-Latin America (IEI-LA), Campinas, SP (Brazil)], email: rodolfo@iei-la.org

2010-07-01

The Chilean, Argentinean and Brazilian power matrixes presented in the last two decades a growth of the non-renewable energy sources share, especially fossil sources, mainly in installed capacity and in a lesser degree in energy production. Greenpeace and the European Renewable Energy Council have elaborated a reference energy scenario together with a scenario analyzing the institution of ample measures for the promotion of renewable energy sources. Feed-in tariffs and auction or bidding mechanisms implemented in Brazil and Argentina and the renewable portfolio standard implemented in Chile allied with the wind industry state in these countries indicate that Chile and Argentina will fulfill the 2020 wind power installed capacity predicted in the reference scenarios, while Brazil will reach the energy revolution scenario prediction. Important energy policy changes are required if the Chile and Argentina energy revolution scenarios wind power installed capacity are to become a reality in 2020. (author)

A short history of the beginnings of hospital information systems in Argentina.

Science.gov (United States)

Yácubsohn, V

2012-01-01

To describe the development of early health information systems in Argentina and their impact on the development of professional societies in the discipline The first hospital information systems and health surveillance systems in Argentina are described and related to the rise of professional organizations for health informatics. The early health information systems in Argentina are related to precursor developments in medical informatics. Argentina saw a number of hospital information systems developed starting in 1977, which had an important influence on the practice and experience in medical informatics in the country, and the participation of Argentine professionals in national, regional, and international activities in the field.

Biotechnology in Argentina: New products, new multilateral challenges

Directory of Open Access Journals (Sweden)

Luciano M. Donadio Linares

2016-06-01

Full Text Available Since 20 years ago, a public-private alliance has transformed Argentina into a remarkable global actor in developing biotechnological products for food and renewable energies. This strategic alliance resulted in the boosting of scientific knowledge, the extension of the production boundary, the expansion of international trade and the creation of the conditions for an integral development. Furthermore, given the characteristics of biotechnology as a new phenomenon, wto has become the field within where a number of disputes take place, disputes which not only controvert trade issues, but also the State’s limits to design and apply public policies on the matter at issue. As a consequence, the present article seeks to, on the one hand, describe how Argentina built its public policy on Biotechnology and, on the other hand, analyze the challenges that Argentina faces within the multilateral trade system

Hongos patógenos de insectos en Argentina (Zygomycetes: Entomophthorales

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C.C López Lastra

2006-06-01

Full Text Available Se informa de tres especies de hongos Entomophthorales en insectos encontrados en cultivos agrícolas en la Provincia de Buenos Aires, Argentina: Zoophthora radicans Batko (Brefeld; Entomophthora planchoniana Cornu y Pandora gammae (Weiser Humber. Se incluyen las medidas de las estructuras fúngicas.Pathogenic fungi of insects from Argentina (Zygomycetes: Entomophthorales. Three species of Entomophthorales entomopathogenic fungi (Zygomycotina: Zygomycetes have been identified from insects in agricultural crops (Buenos Aires Province, Argentina: Zoophthora radicans Batko (Brefeld; Entomophthora planchoniana Cornu and Pandora gammae (Weiser Humber. Fungal structure measurements are reported. Rev. Biol. Trop. 54(2: 311-315. Epub 2006 Jun 01.

Erosion of the Alps: use of Rb-Sr isotopic data from molassic sediments to identify the ages of the metamorphism recorded by the eroded rocks

International Nuclear Information System (INIS)

Henry, P.; Deloule, E.

1994-01-01

Rb-Sr isotopic data from Oligocene and Miocene peri-alpine molassic sediments allow us to identify the different periods for which the eroded rocks have or have not recorded an alpine metamorphism. The Chattian and the Burdigalian sediments result from the erosion of rocks for which the latest metamorphic event was variscan, while the Stampian, Aquitanian and ''Helvetian'' sediments show evidence for the erosion of rocks which have recorded alpine metamorphic events. The application of this method to old detrital sediments could permit determination of the ages of the tectonic events which occurred in the sediment source regions. (authors). 18 refs., 6 figs

Argentina's experience with parallel exchange markets: 1981-1990

OpenAIRE

Steven B. Kamin

1991-01-01

This paper surveys the development and operation of the parallel exchange market in Argentina during the 1980s, and evaluates its impact upon macroeconomic performance and policy. The historical evolution of Argentina's exchange market policies is reviewed in order to understand the government's motives for imposing exchange controls. The parallel exchange market engendered by these controls is then analyzed, and econometric methods are used to evaluate the behavior of the parallel exchange r...

Pb-Pb zircon ages of the Porto Nacional high-grade metamorphic terrain, northern portion of the Goias Massif, central Brazil

Energy Technology Data Exchange (ETDEWEB)

Gorayeb, Paulo Sergio de Sousa; Moura, Candido Augusto Veloso [Para Univ., Belem, PA (Brazil). Centro de Geociencias]. E-mail: gorayebp@ufpa.br; c_moura@ufpa.br; Barros, Gisele Ribeiro de [Para Univ., Belem, PA (Brazil). Programa Institucional de Bolsas de Iniciacao Cientifica (PIBIC)]. E-mail: agbarros@amazon.com.br

2000-03-01

Single zircon Pb-evaporation ages were determined for a mafic granulite, two enderbites and a kinzigite of the Porto Nacional High-Grade Metamorphic Terrain (PNHGT) in the Goias massif. Zircons from mafic granulites and one of the enderbites of yielded average {sup 207} Pb/{sup 206} Pb ages of 2125{+-}3 Ma and 2153{+-}1 Ma, respectively, being interpreted as minimum ages of the igneous protoliths. The other enderbite, whose zircons presented round terminations, yielded an average {sup 207} Pb/{sup 206} Pb age of 2097 {+-} 2 Ma. Zircons from the kinzigite, displaying cores and rims overgrowth, presented {sup 207} Pb/{sup 206} Pb ages ranging between 2027 and 2115 Ma. However, a very homogeneous zircon crystal without overgrowth yielded age of 2100 {+-} 2 Ma, with a distinctive low Th/U value (0.02). This zircon is interpreted as a metamorphic crystal and its age probably sets the age of the granulite facies metamorphism, indicating that the PNHGT is a result of the Transamazonian thermotectonic event. (author)

Constraint-plane-based synthesis and topology variation of a class of metamorphic parallel mechanisms

International Nuclear Information System (INIS)

Gan, Dongming; Dias, Jorge; Seneviratne, Lakmal; Dai, Jian S.

2014-01-01

This paper investigates various topologies and mobility of a class of metamorphic parallel mechanisms synthesized with reconfigurable rTPS limbs. Based on the reconfigurable Hooke (rT) joint, the rTPS limb has two phases which result in parallel mechanisms having ability of mobility change. While in one phase the limb has no constraint to the platform, in the other it constrains the spherical joint center to lie on a plane which is used to demonstrate different topologies of the nrTPS metamorphic parallel mechanisms by investigating various relations (parallel or intersecting) among the n constraint planes (n = 2,3,..,6). Geometric constraint equations of the platform rotation matrix and translation vector are set up based on the point-plane constraint, which reveals mobility and redundant geometric conditions of the mechanism topologies. By altering the limbs into the non-constraint phase without constraint plane, new mechanism phases are deduced with mobility change based on each mechanism topology.

Carboniferous high-pressure metamorphism of Ordovician protoliths in the Argentera Massif (Italy), Southern European Variscan belt

Science.gov (United States)

Rubatto, Daniela; Ferrando, Simona; Compagnoni, Roberto; Lombardo, Bruno

2010-04-01

The age of high-pressure metamorphism is crucial to identify a suitable tectonic model for the vast Variscan orogeny. Banded H P granulites from the Gesso-Stura Terrain in the Argentera Massif, Italy, have been recently described (Ferrando et al., 2008) relicts of high-pressure metamorphism in the western part of the Variscan orogen. Bulk rock chemistry of representative lithologies reveals intermediate silica contents and calc-alkaline affinity of the various cumulate layers. Enrichment in incompatible elements denotes a significant crustal component in line with intrusion during Ordovician rifting. Magmatic zircon cores from a Pl-rich layer yield scattered ages indicating a minimum protolith age of 486 ± 7 Ma. Carboniferous zircons (340.7 ± 4.2 and 336.3 ± 4.1 Ma) are found in a Pl-rich and a Pl-poor layer, respectively. Their zoning, chemical composition (low Th/U, flat HREE pattern and Ti-in-zircon temperature) and deformation indicate that they formed during the high-pressure event before decompression and mylonitisation. The proposed age for high-pressure metamorphism in the Argentera Massif proves that subduction preceded anatexis by less than 20 Ma. The new data allow a first-order comparison with the Bohemian Massif, which is located at the eastern termination of the Variscan orogen. Similarities in evolution at either end of the orogen support a Himalayan-type tectonic model for the entire European Variscides.

Tectonic superposition of the Kurosegawa Terrane upon the Sanbagawa metamorphic belt in eastern Shikoku, southwest Japan

International Nuclear Information System (INIS)

Suzuki, Hisashi; Isozaki, Yukio; Itaya, Tetsumaru.

1990-01-01

Weakly metamorphosed pre-Cenozoic accretionary complex in the northern part of the Chichibu Belt in Kamikatsu Town, eastern Shikoku, consists of two distinct geologic units; the Northern Unit and Southern Unit. The Northern Unit is composed mainly of phyllitic pelites and basic tuff with allochthonous blocks of chert and limestone, and possesses mineral paragenesis of the glaucophane schist facies. The Southern Unit is composed mainly of phyllitic pelites with allochthonous blocks of sandstone, limestone, massive green rocks, and chert, and possesses mineral paragenesis of the pumpellyite-actinolite facies. The Southern Unit tectonically overlies the Northern Univ by the south-dipping Jiganji Fault. K-Ar ages were dated for the recrystallized white micas from 11 samples of pelites and basic tuff in the Northern Unit, and from 6 samples of pelites in the Southern Unit. The K-Ar ages of the samples from the Northern Unit range in 129-112 Ma, and those from the Southern Unit in 225-194 Ma. In terms of metamorphic ages, the Northern Unit and Southern Unit are referred to the constituents of the Sanbagawa Metamorphic Belt, and to those of the Kurosegawa Terrane, respectively. Thus, tectonic superposition of these two units in the study area suggests that the Kurosegawa Terrane occurs in a higher structural position over the Sanbagawa Metamorphic Belt in eastern Shikoku. (author)

Metamorphic history and geodynamic significance of the Early Cretaceous Sabzevar granulites (Sabzevar structural zone, NE Iran

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M. Nasrabady

2011-11-01

Full Text Available The Iranian ophiolites are part of the vast orogenic suture zones that mark the Alpine-Himalayan convergence zone. Few petrological and geochronological data are available from these ophiolitic domains, hampering a full assessment of the timing and regimes of subduction zone metamorphism and orogenic construction in the region. This paper describes texture, geochemistry, and the pressure-temperature path of the Early Cretaceous mafic granulites that occur within the Tertiary Sabzevar ophiolitic suture zone of NE Iran. Whole rock geochemistry indicates that the Sabzevar granulites are likely derived from a MORB-type precursor. They are thus considered as remnants of a dismembered dynamo-thermal sole formed during subduction of a back-arc basin (proto-Sabzevar Ocean formed in the upper-plate of the Neotethyan slab. The metamorphic history of the granulites suggests an anticlockwise pressure-temperature loop compatible with burial in a hot subduction zone, followed by cooling during exhumation. Transition from a nascent to a mature stage of oceanic subduction is the geodynamic scenario proposed to accomplish for the reconstructed thermobaric evolution. When framed with the regional scenario, results of this study point to diachronous and independent tectonic evolutions of the different ophiolitic domains of central Iran, for which a growing disparity in the timing of metamorphic equilibration and of pressure-temperature paths can be expected to emerge with further investigations.

La mortalidad por armas de fuego en Argentina entre 1990 y 2008 Firearm mortality in Argentina, 1990-2008

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Marina Gabriela Zunino

2012-04-01

Full Text Available Este es un estudio epidemiológico descriptivo de la mortalidad por armas de fuego en Argentina, 1990-2008. Se analizaron los porcentajes y las tasas de mortalidad por armas de fuego entre las jurisdicciones del país. Los datos provienen de la Dirección de Estadística e Información en Salud, Ministerio de Salud y Ambiente, República Argentina. Entre 1990-2008 se produjeron 358.484 muertes por causas externas de las cuales el 16,6% (59.339 correspondieron a armas de fuego. La Provincia de Buenos Aires presentó el porcentaje y tasas cruda y ajustada superiores. Las jurisdicciones de la Región Pampeana (incluye Provincia de Buenos Aires presentaron un perfil más homogéneo y similar al del país: aumento de las tasas en 1999-2002 y disminución en 2003-2006. Estos hallazgos se explicarían en parte por el deterioro socioeconómico vivido en Argentina a fines del siglo XX, que habría tenido mayor impacto en Provincia de Buenos Aires, por ser ésta una de las provincias con mayor desarrollo y dinamismo económico de Argentina. La situación de Provincia de Buenos Aires habría estado agravada por el hecho de tener una de las fuerzas policiales más represivas del país.This is a descriptive epidemiological study of firearm mortality in Argentina, 1990-2008. The study compared the firearm mortality percentages and rates between the country's jurisdictions. The data are from the Office of Health Statistics and Information, Ministry of Health. From 1990 to 2008 there were 358,484 deaths from external causes, of which 16.6% (59,339 were caused by firearms. The Province of Buenos Aires showed the highest percentage and crude and adjusted rates. The jurisdictions in the Pampeana region (including the Province of Buenos Aires showed a more homogeneous profile, similar to that of the country as a whole, with an increase in the rates from 1999 to 2002 and a decrease from 2003 to 2006. These findings are partially explained by the country

Metamorphic evolution and U-Pb zircon SHRIMP geochronology of the Belizário ultramafic amphibolite, Encantadas Complex, southernmost Brazil

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Hartmann Léo A.

2003-01-01

Full Text Available The integrated investigation of metamorphism and zircon U-Pb SHRIMP geochronology of the Belizário ultramafic amphibolite from southernmost Brazil leads to a better understanding of the processes involved in the generation of the Encantadas Complex. Magmatic evidence of the magnesian basalt or pyroxenite protolith is only preserved in cores of zircon crystals, which are dated at 2257 ± 12 Ma. Amphibolite facies metamorphism M1 formed voluminous hornblende in the investigated rock possibly at 1989 ± 21 Ma. This ultramafic rock was re-metamorphosed at 702±21 Ma during a greenschist facies eventM2; the assemblage actinolite + oligoclase + microcline + epidote + titanite + monazite formed by alteration of hornblende. The metamorphic events are probably related to the Encantadas Orogeny (2257±12 Ma and Camboriú Orogeny (~ 1989 Ma of the Trans-Amazonian Cycle, followed by an orogenic event (702±21 Ma of the Brasiliano Cycle. The intervening cratonic period (2000-700 Ma corresponds to the existence of the Supercontinent Atlantica, known regionally as the Rio de la Plata Craton.

Prograde and retrograde metamorphic processes in high-pressure subduction zone serpentinites from East Thessaly, Greece

Science.gov (United States)

Koutsovitis, Petros

2016-04-01

The East Thessaly region, Central Greece, includes metaophiolitic mélange formations which extend from the eastern foothills of Mt. Olympus and Ossa, throughout the Agia basin, Mt. Mavrovouni (Sklithro region), South Pelion and reaching up to northeast Othris (regions of Aerino and Velestino). They appear in the form of dispersed and deformed thrust sheets having been variably emplaced onto Mesozoic platform series rocks of the Pelagonian tectonostratigraphic zone[1]. These formations consist mainly of serpentinites, as well as metasediments, metagabbros, metadolerites, rodingites, ophicalcites, talc-schists and chromitites. Based upon petrographic observations, mineral chemistry data and XRD patterns, the subduction zone-related serpentinites from the regions of Potamia, Anavra, Aetolofos and Kalochori-Chasanbali (Agia basin), as well as from the regions of Aerino and Velestino, are characterized by the progressive transformation of lizardite to antigorite and are distinguished into two groups. The first group includes serpentinites from the metaophiolitic formations of Potamia, Anavra, Aerino and Velestino, which are marked by destibillization of lizardite to antigorite, mostly along the grain boundaries of the lizardite mesh textured relics. The presence of lizardite and antigorite in almost equal amounts indicates medium-temperature blueschist facies metamorphic conditions (˜340-370 ° C; P≈10-11 kbar)[2,3,4]. The second serpentinite group appears in the regions of Aetolofos and Kalochori, characterized by the predominance of antigorite, the minor occurrence of lizardite and the complete replacement of spinel by Cr-magnetite. The absence of metamorphic olivine suggests that these serpentinites were most likely formed at slightly higher temperature and pressure conditions compared to the first serpentinite group, corresponding to medium or high temperature blueschist facies metamorphism (˜360-380 ° C; P≈12 kbar)[2,3,4]. These metamorphic conditions are

Greisen deposits associated to carboniferous post-orogenic granites with mineralization potential, Sierra de Fiambala, Catamarca, Argentina

International Nuclear Information System (INIS)

Fogliata, A. S.; Rubinstein, N. R.; Avila, J. C.; Baez, M.

2008-01-01

The Fiambala range is located in the central south part of the province of Catamarca, Western Sierras Pampeanas, Argentina. It is largely conformed by Precambrian metamorphic rocks, a Cambrian granitic intrusive, Ordovician basic and ultra basic rocks and epi zonal Carboniferous granites (Los Ratones, El Salto and Ayacucho Granites). The Carboniferous granites are sub alkaline, weakly peraluminous, high silica (except for the porphyritic facies of Los Ratones granite) and moderately enriched in K. Contents of trace elements and REE indicate that El S alto and Ayacucho granites and the granular facies of Los Ratones granite have characteristics of evolved and differentiated granite associated with hydrothermal systems. The variations of trace elements, particularly Sn, W, U, Rb, Ba, Zr and Sr suggest that they correspond to granites with mineralization potential. Genetically linked to these granites there are Sn, W, U and minor base metals greisen deposits. The hydrothermal process that yield to these deposits involved two main alteration stages, beginning with alkali metasomatism follow by greissenization. According to the isotopic ages the hydrothermal processes postdate about 1 Ma the magmatic activity. The analyses of the granites and the associated greisen deposits confirm that the post orogenic carboniferous magmatism is the major metallogenetic control of the ore deposits from the studied area. This metallogenetic control could be a useful tool in prospecting similar deposits in the rest of the Western Sierras Pampeanas. (Author)

First results of U-Pb dating of metamorphic rocks of the Greater Antilles arc: age of the Mabujina complex (Cuba)

International Nuclear Information System (INIS)

Bibikova, E.V.; Somin, M.L.; Gracheva, T.V.; Makarov, V.A.; Mil'yan, G.; Shukolyukov, Yu.A.; AN SSSR, Moscow

1988-01-01

U-Pb-dating of zircons, entering the composition of metamorphic rocks of the Mabujina complex, was conducted in order to solve the problem concerming the place of metamorphic complexes in the structure and tectonic evolution of the Greater Antilles arc. The accuracy of uranium and lead determination was equal to ± 1%, the accuracy of lead isotopic ratio determination with the use of TSN-206A mass-spectrometer- ±0.15%. Isotope data showed, that all examined zircons crystallized about 100 mil. years ago

Paleozoic age of high-pressure metamorphic rocks of the Dakh salient, North-Western Caucasus: results of U-Pb-geochronological study

International Nuclear Information System (INIS)

Somin, M.L.; Levchenkov, O.A.; Kotov, A.B.; Makeev, A.F.; Komarov, A.N.; Ro, N.I.; Lavrishchev, V.A.; Lebedev, V.A.

2007-01-01

U-Pb geochronological studies of an ancient component of the Dakh salient, i.e. metaaplites, which are vein fine-grained rocks made up by albite, microcline, quartz and potash mica, were made. Besides, K-Ar dating of granodiorites breaking through metamorphic rocks was conducted. U-Pb dating of accessory zircons (353 mln. years) defines the lower age boundary of the Dakh salient rock metamorphism. Its upper boundary was identified by K-Ar dating (301 ± 10 mln. years) of hornfels blende of nonmetamophized granodiorites [ru

Las Dactylopiidae y Diaspididae (Hemiptera, Coccoidea de la Colección Kenneth Hayward, Tucumán, Argentina The Dactylopiidae and Diaspididae (Hemiptera, Coccoidea of the Kenneth Hayward Collection, Tucumán, Argentina

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Lucía E. Claps

2006-03-01

Full Text Available Se estudió la colección Kenneth Hayward depositada parte en el Instituto Miguel Lillo (IMLA y parte en la Estación Experimental Agroindustrial "Obispo Colombres" (EEAOC de Tucumán, Argentina. Se citan cuatro especies de Dactylopiidae y 32 de Diaspididae con sus respectivas plantas huéspedes. Se redescribe e ilustra a Duplaspidiotus koehleri Lizer y Trelles y Pallulaspis lantanae Green & Laing, descriptas originalmente para la Argentina. Se cita por primera vez al género Rugaspidiotus Mc Gillivary para la Argentina.The Kenneth Hayward collection housed at the Instituto Miguel Lillo (IMLA and at Estación Experimental Agroindustrial "Obispo Colombres" (EEAOC both in Tucumán, Argentina, was studied. Four Dactylopiidae and 32 Diaspididae species with their host plants are listed. Duplaspidiotus koehleri Lizer y Trelles and Pallulaspis lantanae Green & Laing, are redescribed and illustrated; the two species were originally described from Argentina. The genus Rugaspidiotus Mc Gillivary is recorded for the first time from Argentina.

Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

Science.gov (United States)

Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

2006-01-01

High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

Floods, Droughts and Farming on the Plains of Argentina and ...

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

2015-04-01

Floods, Droughts and Farming on the Plains of Argentina and Paraguay, Pampas and Chaco Regions ... End Date. April 1, 2015 ... Argentina, South America, Paraguay, North and Central America ... IDRC is now accepting applications for this year's IDRC Doctoral Research Awards (IDRA). ... Careers · Contact Us · Site map.

Towards an integrated magmatic, structural and metamorphic model for the 1.1-0.9 Ga Sveconorwegian orogeny

Science.gov (United States)

Slagstad, Trond; Roberts, Nick M. W.; Røhr, Torkil S.; Marker, Mogens K.

2013-04-01

Orogeny involves magmatic, metamorphic, deformational and erosional processes that are caused by or lead to crustal thickening and the development of high topography. In general, these processes operate along the margins of continental plates, either as a result of subduction of oceanic crust (accretionary) or collision between two or more continental plates (collisional). Many of these processes are common to accretionary and collisional orogeny, and do not uniquely discriminate between the two. With only a fragmented geological record, unravelling the style of orogenesis in ancient orogens may, therefore, be far from straightforward. Adding to the complexity, modern continental margins, e.g., the southern Asian margin, display significant variation in orogenic style along strike, rendering along-strike comparisons and correlations unreliable. The late Mesoproterozoic Sveconorwegian province in SW Baltica is traditionally interpreted as the eastward continuation of the Grenville province in Canada, resulting from collision with Amazonia and forming a central part in the assembly of the Rodinia supercontinent. We recently proposed that the Sveconorwegian segment of this orogen formed as a result of accretionary processes rather than collision. This hypothesis was based mainly on considerations of the Sveconorwegian magmatic evolution. Here, we show how the metamorphic/structural record supports (or at least may be integrated in) our model as well. The key elements in our accretionary model are: 1) formation of the Sirdal Magmatic Belt (SMB) between 1070 and 1020 Ma, most likely representing a continental arc batholith. Coeval deformation and high-grade metamorphism farther east in the orogen could represent deformation in the retroarc. 2) cessation of SMB magmatism at 1020 Ma followed by UHT conditions at 1010-1005 Ma, with temperatures in excess of 1000°C at 7.5 kbar. Subduction of a spreading ridge at ca. 1020 Ma would result in an end to arc magmatism and

The diagenesis-metamorphism limit in pelitic rocks: an X-ray diffraction and decomposition study of illite and interstratified illite/smectite minerals

International Nuclear Information System (INIS)

Gharrabi, M.

1995-01-01

The definition of the limit between diagenesis and metamorphism has long been debated. Various approaches have been used to describe this limit including mineral reaction such as the appearance of pyrophyllite, illite crystallinity and rock textures (i.e. the development of schistosity). The aim of this study is to characterize the illite clays transformation during this transition. Study of the (001) and (003) XRD peaks of illite and illite-rich interstratified illite/smectite (I/S) by decomposition of XRD spectra allows to define the transformation that affect these minerals in the transition from extensive diagenesis to low grade metamorphism. We studied Paleozoic pelites from the Illinois Basin (USA), Cornwall (UK), Brittany (France) and the Anti-Atlas mountains and the Eastern-Haou/Basin (Morocco) that have undergone this transition. Illite clays pass through three evolutionary stages during the transition from diagenesis to metamorphism: advanced diagenesis where the population of illite particles is composed of the following phases: interstratified illite/smectite (I/S), small illite crystallites (PCI) and large illite crystallites (WCI). The composition of I/S particles that contain approximately 95 % illite layers changes very little at low temperatures even over long periods of time. The most important change during this stage is the reduction in the amount of this phase. These I/S particles (<5% smectite layers) dissolve and furnish the chemical constituents necessary for the growth of PCI and WCI before they are transformed into 100 % illite. Particles of PCI also contain smectite interlayers in their structure. These smectite interlayers may be considered as a characteristic of diagenetic conditions. The second stage, corresponding to anchizone metamorphism is characterized by the disappearance of I/S. The disappearance is caused by higher thermal regime. In the last stage corresponding to epizone metamorphism there exists only one population of illite

The regulatory control of radioactive sources in Argentina

International Nuclear Information System (INIS)

Rojkind, R.H.

1998-01-01

Argentina has been conducting nuclear activities for more than forty years, and had established a Regulatory Authority as early as in 1956. Procedures for compliance monitoring and enforcement have been in use in the regulatory control of radioactive sources, and regulatory standards and regulations were in force in Argentina before the accident in Goiania. The conclusions drawn from the Goiania accident encouraged the Argentine authorities to improve some regulatory procedures and helped to enhance the quality of the regulatory process. As a result, the effectiveness of the control of spent radioactive sources has gradually increased, and enforcement actions to prevent radioactive sources ending up in the public domain have improved. Lessons learned in Argentina from the accident in Goiania are presented as well as the main characteristics of an effective enforcement programme to prevent radiological accidents when radioactive sources are used for industrial, medical, research and teaching purposes. (author)

Measurements of atmospheric fallout in Argentina

International Nuclear Information System (INIS)

Canoba, A.C.; Lopez, F.O.; Bruno, H.A.

1998-01-01

With the purpose of studying the radioactive fallout present in Argentina from atmospheric nuclear explosions tests that have been conducted recently, an environmental monitoring program, outside the influence of nuclear facilities of Argentina, was undertaken during 1996 and 1997. The levels of Cs-137 and Sr-90 were analysed in samples of air, deposited material (rainwater), milk, an average meal of a standard man and food. During this period, a total of 630 radiochemical analysis were performed on 325 samples of the different matrices described. The concentration levels of the radionuclides analysed in the different environmental matrices are presented and are compared with the values obtained in the environmental monitoring program done during the period 1960-1981. (author) [es

Metamorphism, P-T-t Conditions of Formation, and Prospects for the Practical Use of Al2SiO5 Polymorphs, Chloritoid, and Staurolite (Yenisei Ridge)

Science.gov (United States)

Kozlov, P. S.

2017-12-01

The Yenisei Ridge is an accretion-collisional orogen located in the southwestern frame of the Siberian Craton in the interfluve between Podkamennaya Tunguska, Angara, Kan, and Yenisei rivers. The Precambrian mono- and polymetamorphic complexes composed predominantly of the Mesoarchean-Neoproterozoic metapelitic rocks have been studied. Based on the typification of metamorphic complexes by pressure, temperature, metamorphic gradient, as well as age of metamorphism, the location scheme of the fields of the Precambrian sedimentary-metamorphic rock which are prospective for searching deposits of high-alumina metamorphic minerals (andalusite, kyanite, and sillimanite, chloritoid, and staurolite) in the Trans-Angara segment of the Yenisei Region, was compiled. The Teya sillimanite and Panimbinsk andalusite deposits, which are confined to the fields of regional metamorphic complexes of iron-alumina metapelites of the And-Sill facies series, are recommended as a priority for the organization of prospecting works and the subsequent involvement to the metallurgical industry. These metapelites are classified as monomineral. Owing to widespread occurrence and abundance of andalusite and sillimanite, the above deposits have significant inferred resources. Stratiform deposits of garnet-staurolite and chloritoid high-alumina rocks are still insufficiently studied and should be investigated further. The prospects for the possible use of high-alumina andalusite and sillimanite together with Middle Tatarka and Kiya nepheline syenite massifs and the bauxites of the Chadobets uplift, already being explored in the region, for production of aluminum oxide, silumin, and aluminum, as well as, the prospects for the expansion of the raw material base of the Boguchansk Electrometallurgical Complex, brought into operation in 2016 in the Lower Angara region, are considered.

Burden of Serious Fungal Infections in Argentina

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Fernando O. Riera

2018-04-01

Full Text Available The number of fungal infections at any given time in Argentina is not known. Here we estimate the burden of serious fungal infections in Argentina for the first time. Specific population statistics were searched from multiple sources, local literature was identified, and estimates made. Some additional data were sourced from the Ministry of Health, the Global Initiative for Asthma (GINA program, and national haematology and transplant societies. Argentina has a population of 43.8 million, with 25% of this total being children under 15 years. The predicted candidemia annual incidence is 2193 cases, with 50% occurring in the ICU. At a 6% prevalence rate, an estimated 593,695 women suffer from recurrent vulvovaginal candidiasis. Invasive aspergillosis is relatively common because of high smoking and chronic obstructive pulmonary disease (COPD rates, with 268 cases in immunocompromised patients and another 1938 in the 168,000 COPD patients admitted to hospital. Asthma is also common, affecting 14% of adults, and so allergic bronchopulmonary aspergillosis (ABPA and severe asthma with fungal sensitization (SAFS are major problems. An estimated 432 cases of cryptococcal meningitis (CM—90% of them in AIDS patients—and 1177 cases of Pneumocystis pneumonia (PCP occur each year. The estimated annual case number of disseminated histoplasmosis is 404 in AIDS patients, almost as frequent as CM. Paracoccidioidomycosis annual incidence is estimated at 219, and coccidioidomycosis at 16 cases. At least 881,023 people (>2.01% in Argentina are affected by a serious fungal disease annually, with considerable morbidity and mortality.

Short-Wavelength Infrared (SWIR) spectroscopy of low-grade metamorphic volcanic rocks of the Pilbara Craton

NARCIS (Netherlands)

Abweny, Mohammad S.; van Ruitenbeek, Frank J A; de Smeth, Boudewijn; Woldai, Tsehaie; van der Meer, Freek D.; Cudahy, Thomas; Zegers, Tanja; Blom, Jan Kees; Thuss, Barbara

This paper shows the results of Short-Wavelength Infrared (SWIR) spectroscopy investigations of volcanic rocks sampled from low-grade metamorphic greenstone belts of the Archean Pilbara Craton in Western Australia. From the reflectance spectra a range of spectrally active minerals were identified,

La letteratura italiana tradotta in Argentina

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Silvia Cattoni

2017-11-01

Full Text Available In due secoli di storia della letteratura argentina, lo sviluppo della letteratura italiana tradotta è in stretto rapporto con i propositi pedagogici o estetici determinati dal contesto culturale dei diversi momenti storici. In linea di massima, è possibile affermare che, dalla conformazione dello Stato nazionale e durante i primi decenni del XX secolo, la traduzione letteraria mirava ad ampliare l’orizzonte culturale di un lettore che si consolidava al ritmo della fiammante nazione. Nelle fasi successive e in stretto rapporto con la politica culturale portata avanti da Victoria Ocampo a partire dal 1931 tramite la rivista Sur e il suo posteriore progetto editoriale, la traduzione è stata soprattutto una pratica di scrittura che ebbe un’influenza decisiva nell’ordito della letteratura nazionale favorendo il suo rinnovo e incentivando le versioni di traduttori argentini. Fu questa un’apertura che favorì, durante la seconda metà del secolo, nel contesto della ricezione della letteratura universale, l’ingresso della letteratura italiana in Argentina. Il presente lavoro tratta in maniera sistematica, ma provvisoria, il panorama della letteratura italiana tradotta in Argentina. Lo scopo principale comporta il registro dei momenti più fecondi e l’interpretazione degli esiti ottenuti nei confronti della traduzione nel sistema letterario nazionale.

Chemical zoning and homogenization of Pasamonte-type pyroxene and their bearing on thermal metamorphism of a howardite parent body

Science.gov (United States)

Miyamoto, M.; Duke, M. B.; Mckay, D. S.

1985-01-01

The Mg-Fe zoning of pyroxenes in Pasamonte and Juvinas eucrites is examined in order to gain a better understanding of the metamorphism in the surface layer of a eucrite/howardite parent body. Three distinct types of Ca-Mg-Fe zoning of Pasamonte pyroxenes are identified. The wide compositional range of the zoned pyroxenes suggests that Pasamonte is less metamorphosed than previously believed. It is also found that a Pasamonte-type pyroxene may yield a Juvinas-type pyroxene by thermal metamorphism. Calculations imply that the homogenization of Juvinas pyroxenes may have occurred during later reheating events rather than during initial cooling.

Distinct metamorphic evolution of alternating silica-saturated and silica-deficient microdomains within garnet in ultrahigh-temperature granulites: An example from Sri Lanka

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P.L. Dharmapriya

2017-09-01

Full Text Available Here we report the occurrence of garnet porphyroblasts that have overgrown alternating silica-saturated and silica deficient microdomains via different mineral reactions. The samples were collected from ultrahigh-temperature (UHT metapelites in the Highland Complex, Sri Lanka. In some of the metapelites, garnet crystals have cores formed via a dehydration reaction, which had taken place at silica-saturated microdomains and mantle to rim areas formed via a dehydration reaction at silica-deficient microdomains. In contrast, some other garnets in the same rock cores had formed via a dehydration reaction which occurred at silica-deficient microdomains while mantle to rim areas formed via a dehydration reaction at silica-saturated microdomains. Based on the textural observations, we conclude that the studied garnets have grown across different effective bulk compositional microdomains during the prograde evolution. These microdomains could represent heterogeneous compositional layers (paleobedding/laminations in the precursor sediments or differentiated crenulation cleavages that existed during prograde metamorphism. UHT metamorphism associated with strong ductile deformation, metamorphic differentiation and crystallization of locally produced melt may have obliterated the evidence for such microdomains in the matrix. The lack of significant compositional zoning in garnet probably due to self-diffusion during UHT metamorphism had left mineral inclusions as the sole evidence for earlier microdomains with contrasting chemistry.

Review of the intrusive, structural and metamorphic history of the Namaqualand geotraverse and environs

International Nuclear Information System (INIS)

Blignault, H.J.; Van Aswegen, G.; Van der Merwe, S.W.

1981-01-01

The Namaqualand excursion is concerned with the geologic strata, stratigraphy and metamorhic history of the Namaqualand geotraverse and its environs. The general aim of the project was to decipher the history and interactions of tectonic, metamorphic and magmatic processes. Isotope dating were used to determine the ages of various rock formations

Legislation and Organization of Radiological Protection in the Republic of Argentina

International Nuclear Information System (INIS)

Gonzalez, A.; Carrea, A.; Nowotny, G.

1979-01-01

The history of legislation and organization of radiological protection goes hack to 1950 in Argentina. The terms of references of the National Commission of Atomic Energy in Argentina are outlined and the actual organization of the authority is also presented. (author)

Migration trends in Argentina: immigration and exile Dinámica migratoria Argentina: inmigración y exilios

Directory of Open Access Journals (Sweden)

Fernando Osvaldo ESTEBAN

2010-10-01

Full Text Available Through the development of a typology of migration flows, the paper reviews the most important trends in the history of Argentina: the massive European immigration, internal migrations, and immigration from neighbouring countries. The paper then discuss the current process of emigration from Argentina, and the return of old immigrants. The paper assess the economic factors involved through an analysis of unemployment, poverty and income distribution indicators in recent years. Finally, the paper examines the possibility of diminishing the recent emigration trend due to economic reasons. A partir de una tipología de flujos migratorios se realiza un repaso de aquellos más importantes en la historia de Argentina: la masiva inmigración europea, las migraciones internas y aquellas provenientes de países limítrofes. Posteriormente describe el actual proceso de emigración de argentinos y retorno de antiguos inmigrantes. Se abordan luego las causas económicas que lo produjeron a través del estudio de la evolución de los indicadores de desempleo, pobreza y distribución del ingreso en el país durante los últimos años. Finalmente, plantea la posibilidad de aprehender este flujo emigratorio como un exilio económico.

76 FR 80870 - Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina

Science.gov (United States)

2011-12-27

... ;D=APHIS-2010-0032. The first commenter acknowledged Argentina's history of successful Medfly control...] Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina AGENCY: Animal and Plant Health... Southern and Central Oases in the southern half of Mendoza Province in Argentina as pest-free areas for...

Dating of retrograde metamorphism in Western Carpathians by K-Ar analysis of muscovites

International Nuclear Information System (INIS)

Cambel, B.; Korikovskij, S.P.; Krasivskaya, I.S.; Arakelyants, M.M.

1986-01-01

Using the K-Ar isotope dating method of muscovites it was found that many retrogradely metamorphosed rocks are the results of Variscan retrograde metamorphism and are not pre-Cambrian or Alpine metamorphites (diaphthorites). Samples for dating were taken from the Western Carpathian crystalline formation. The content of radiogenic argon was determined by mass spectrometry using the method of isotope dilution. (M.D.)

Crisis y perspectivas de la industria automotriz argentina

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Damián Andrés Bil

2016-12-01

Full Text Available Con la conformación del Mercosur, la automotriz argentina se expandió. Durante los últimos años alcanzó récords de producción, exportaciones y ventas; al punto que se la señala como ejemplo de una nueva etapa productiva. No obstante, desde finales de 2013 el complejo experimenta una crisis que provocó una considerable caída de los indicadores, con suspensiones e incluso despidos en las empresas de autopartes. En este artículo, proponemos revisar los indicadores de la actividad (escala y mercado, productividad, costo laboral, saldo comercial en perspectiva histórica y en el contexto de la competencia internacional. El objetivo es determinar si la situación actual corresponde a un inconveniente coyuntural, o si por el contrario expresa límites históricos que la automotriz argentina no ha superado; y sus perspectivas. *Palabras clave: Argentina, automotriz, crisis, competitividad, Mercosur

Argentina: Brief Overview of Argentina’s INIS Activities

International Nuclear Information System (INIS)

Bavio, Mercedes

2015-01-01

Argentina works in close collaboration with the IAEA on its technical cooperation program, both on national projects within their national program plan, including its thematic areas, as well as on regional projects through the ARCAL agreement. In the field of horizontal cooperation, Argentina engages in technology transfer, training fellows and receiving scientific visits. Argentina has been a member of the International Nuclear Information System (INIS) since 1970, and was among the first IAEA Member States to agree to participate in the system. As a member, we have been involved in the various activities carried out by the IAEA, disseminating the research and development of our researchers and scientists in nuclear and related subjects and promoting INIS activities. The National Atomic Energy Commission (CNEA) is the INIS National Center. Contributions to the INIS database nationwide are made through the CNEA's Information Centers: Eduardo Savino Information Center (CIES, Constituyentes Atomic Center), Leo Falicov Library (Bariloche Atomic Center) and the Library of the Nuclear Regulatory Authority (ARN)

Coronitic metagabbro and eclogite from the Grenville Province of western Quebec: interpretation of U-Pb geochronology and metamorphism

International Nuclear Information System (INIS)

Indares, A.; Dunning, G.

1997-01-01

We present new U-Pb and metamorphic data on high-pressure coronitic metagabbros from three distinct structural settings in the Parautochthonous belt of the Grenville Province in western Quebec. Intrusive ages are (i) 1217 -10 +15 Ma, for metagabbro close to the Grenville Front, correlative with the Sudbury dykes, defined in Ontario; (ii) 1403 -11 +14 Ma for an eclogitized lens at the base of the highest structural level (SL4), a new age for mafic magmatism in the western Grenville; and (iii) 1218 -34 +53 Ma for metagabbro from SL4, interpreted as correlative with metagabbros from the Algonquin and Shawanaga domains in Ontario. Metamorphism in all cases is Grenvillian, with the best constrained age of 1069 ± 3 Ma for the metagabbro of SL4. Metamorphic grade increases from the Grenville Front to the south. The mafic rocks preserve relict igneous textures overprinted by garnet + clinopyroxene that developed as coronas and (or) pseudomorphs after igneous phases. The highest grade metagabbros contain omphacite and some lack primary plagioclase, therefore being eclogites. However, interpretation of textures and mineral chemistry indicates that they were equilibrated during decompression (at 1350 MPa and 720 o C, sample 51: and at 1200 MPa and 740 o C, sample 29), so maximum depths of burial remain unconstrained. Their evolution is interpreted as follows: (i) high-pressure metamorphism by burial of the Laurentian margin under accreted terranes thrust toward the northwest between 1080 and 1060 Ma; (ii) residence at intermediate crustal levels, for a few tens of millions of years; and (iii) rapid exhumation by renewed thrusting that led to the emplacement of the high-pressure units over the northerly adjacent structural units of the Parautochthonous Belt. (author)

Argentina: Social Sectors in Crisis. A World Bank Country Study.

Science.gov (United States)

World Bank, Washington, DC.

Based on the findings of a two month visit to Argentina by a World Bank Mission in November/December of 1988, this report summarizes current economic, education, and social policies in Argentina. The four major areas targeted are the social sectors, education, health care, and housing. The analysis identifies critical problems in the organization…

The role of evaporites in the formation of gems during metamorphism of carbonate platforms: a review

Science.gov (United States)

Giuliani, Gaston; Dubessy, Jean; Ohnenstetter, Daniel; Banks, David; Branquet, Yannick; Feneyrol, Julien; Fallick, Anthony E.; Martelat, Jean-Emmanuel

2018-01-01

The mineral and fluid inclusions trapped by gemstones during the metamorphism of carbonate platform successions are precious markers for the understanding of gem genesis. The nature and chemical composition of inclusions highlight the major contribution of evaporites through dissolution or fusion, depending on the temperature of formation from greenschist to granulite facies. The fluids are highly saline NaCl-brines circulating either in an open system in the greenschist facies (Colombian and Afghan emeralds) and with huge fluid-rock metasomatic interactions, or sulphurous fluids (ruby, garnet tsavorite, zoisite tanzanite and lapis-lazuli) or molten salts formed in a closed system with a low fluid mobility (ruby in marble) in the conditions of the amphibolite to granulite facies. These chloride-fluoride-sulphate ± carbonate-rich fluids scavenged the metals essential for gem formation. At high temperature, the anions SO4 2-, NO3 -, BO3 - and F- are powerful fluxes which lower the temperature of chloride- and fluoride-rich ionic liquids. They provided transport over a very short distance of aluminium and/or silica and transition metals which are necessary for gem growth. In summary, the genetic models proposed for these high-value and ornamental gems underline the importance of the metamorphism of evaporites formed on continental carbonate shelves and emphasise the chemical power accompanying metamorphism at moderate to high temperatures of evaporite-rich and organic matter-rich protoliths to form gem minerals.

Possible zircon U-Pb evidence for Pan-African granulite-facies metamorphism in the Mozambique belt of southern Tanzania

International Nuclear Information System (INIS)

Coolen, J.J.M.M.M.

1982-01-01

Four zircon fractions of garnet-bearing two-pyroxene granulite, from the Furua granulite complex of southern Tanzania, plot very close to concordia. A discordia yields a lower intercept at 652 +- 10 Ma, an age slightly higher than the Rb-Sr whole-rock and mineral ages reported from the surrounding amphibolite-facies rocks. The U-Pb systematics indicate the presence of a very small amount of older (2-3 Ga) radiogenic lead. The zircon data may be interpreted as indicating an event of granulite-facies metamorphism during the Pan-African thermotectonic episode. This interpretation is at variance with current models postulating that the granulite complexes in the Mozambique belt are relicts of older, possibly Archaean events of metamorphism. (Auth.)

Sr and Nd isotope composition of the metamorphic, sedimentary and ultramafic xenoliths of Lanzarote (Canary Islands): Implications for magma sources

Science.gov (United States)

Aparicio, Alfredo; Tassinari, Colombo C. G.; García, Roberto; Araña, Vicente

2010-01-01

The lavas produced by the Timanfaya eruption of 1730-1736 (Lanzarote, Canary Islands) contain a great many sedimentary and metamorphic (metasedimentary), and mafic and ultramafic plutonic xenoliths. Among the metamorphosed carbonate rocks (calc-silicate rocks [CSRs]) are monomineral rocks with forsterite or wollastonite, as well as rocks containing olivine ± orthopyroxene ± clinopyroxene ± plagioclase; their mineralogical compositions are identical to those of the mafic (gabbros) and ultramafic (dunite, wherlite and lherzolite) xenoliths. The 87Sr/ 86Sr (around 0.703) and 143Nd/ 144Nd (around 0.512) isotope ratios of the ultramafic and metasedimentary xenoliths are similar, while the 147Sm/ 144Nd ratios show crustal values (0.13-0.16) in the ultramafic xenoliths and mantle values (0.18-0.25) in some CSRs. The apparent isotopic anomaly of the metamorphic xenoliths can be explained in terms of the heat source (basaltic intrusion) inducing strong isotopic exchange ( 87Sr/ 86Sr and 143Nd/ 144Nd) between metasedimentary and basaltic rocks. Petrofabric analysis also showed a possible relationship between the ultramafic and metamorphic xenoliths.

Argentina e Irán entre 1989 y 1999: Entre las sobras de los atentados terroristas y el cambio de política exterior argentina

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Paulo Botta

2012-01-01

Full Text Available Las relaciones argentino-iraníes se encuentran, a nivel político, en el punto más bajo de su historia. Suele afirmarse que tal situación es la relación directa de los atentados terroristas ocurridos en Buenos Aires en 1992 y 1994 donde las autoridades judiciales argentinas han presentado indicios que relacionarían a funcionarios iraníes. En este trabajo se afirma que aunque tales hechos han tenido influencia las relaciones argentino iraníes constituyen una variable dependiente de los modelos de inserción internacional de Argentina. En tal sentido, la década del gobierno de Carlos Menem (1989-1999 es estudiada como modelo para analizar tales cambios en la política exterior argentina y su impacto en las relaciones argentino-iraníes. Por otra parte, se ha incluido en el análisis el papel de lobbies comunitarios como grupos con incidencia en el proceso de toma de decisiones además de considerar las influencias externas como condicionantes de la política exterior argentina.

Gender, age, social disadvantage and quitting smoking in Argentina and Uruguay.

Science.gov (United States)

Niedzin, Mirosław; Gaszyńska, Ewelina; Krakowiak, Jan; Saran, Tomasz; Szatko, Franciszek; Kaleta, Dorota

2018-03-14

Cessation of tobacco use has the potential to provide the greatest immediate benefits for tobacco control. Understanding the social determinants of smoking cessation is an essential requirement for increasing smoking cessation at the population level. The purpose of this study was to analyze the socio-economic dimensions associated with cessation success among adults in Argentina and Uruguay. Data from the Global Adult Tobacco Survey (GATS), a cross-sectional, population-based, nationally representative survey conducted in Argentina (n=5,383) and Uruguay (n=4,833) was utilized. Univariable and multivariable logistic regression analyses with results being presented as odds ratios (OR) with 95% confidence intervals were applied to study differences among those respondents who sustained smoking abstinence (≥1 year) and those who continued smoking. The GATS study revealed that social gradients in tobacco quitting exist in Argentina and Uruguay. Being aged 25-34, particularly men in Uruguay, women in Argentina, low educated men in Argentina and having a lower asset index were associated with reduced odds for quitting. Factors that are driving differences in smoking cessation between diverse social groups in Latin America countries need to be considered when implementing relevant interventions to ensure tobacco control strategies work effectively for all population segments.

Economy Profile of Argentina

OpenAIRE

World Bank Group

2017-01-01

Doing Business 2018 is the 15th in a series of annual reports investigating the regulations that enhance business activity and those that constrain it. This economy profile presents the Doing Business indicators for Argentina. Doing Business presents quantitative indicators on business regulation and the protection of property rights that can be compared across 190 economies; for 2018 Arge...

Metamorphic history of the Central Pyrenees Part II, Valle de Arán, Sheet 4

NARCIS (Netherlands)

Zwart, H.J.

1963-01-01

The structural geology and metamorphic petrology of the Bosost area in the Valle de Arán (Central Pyrenees) is discussed. The rocks exposed in this area consist of Cambro-Ordovician mica-schists with numerous granite and pegmatite bodies, phyllites and limestones; Silurian slates and schists and

Provencance of the late Proterozoic to early Cambrian metaclastic sediments ot the Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera Oriental, Argentina

DEFF Research Database (Denmark)

Drobe, M.; López de Luchi, M.; Steenken, A.

2009-01-01

Provenance studies have been performed utilising major and trace elements, Nd systematics, whole rock Pb-Pb isotopes and zircon U/Pb SHRIMP data on metasedimentary rocks of the Sierra de San Luis (Nogolí Metamorphic Complex, Pringles Metamorphic Complex, Conlara Metamorphic Complex and San Luis...... is depicted for all the complexes using major and trace elements. The Pringles Metamorphic Complex shows indications for crustal recycling, pointing to a bimodal provenance. Major volcanic input has to be rejected due to Th/Sc, Y/Ni and Cr/V ratios for all units. The eNd(540 Ma) data is lower for the San Luis...... Formation and higher for the Conlara Metamorphic Complex, as compared to the other units, in which a good consistency is given. This is similar to the TDM ages, where the metapsammitic samples of the San Luis Formation are slightly older. The spread of data is largest for the Pringles Metamorphic Complex...

Comparative study of the thermoluminescence properties of natural metamorphic quartz belonging to Turkey and Spain

International Nuclear Information System (INIS)

Topaksu, M.; Dogan, T.; Yüksel, M.; Kurt, K.; Topak, Y.; Yegingil, Z.

2014-01-01

The aim of this study is to investigate the sensitization of the thermoluminescence (TL) peak of metamorphic quartzes from Adiyaman in Turkey (TMQ) and from Madrid in Spain (SMQ). Quartz samples of two different origins were β-irradiated between ∼6.689 Gy and 4816 Gy at room temperature. X-ray diffraction analysis has indicated that both TMQ and SMQ have the same crystal structure. Chemical analyses of both TMQ and SMQ were performed using the XRF technique. The preheat processes were carried out at 125 °C for 10 s in the TL measurement. TMQ and SMQ samples have different TL properties in two ways. First TMQ has four first order TL glow peaks while SMQ has five first order TL peaks and secondly, the observed dose sensitivity of TMQ samples is higher than the SMQ samples. - Highlights: • The thermoluminescence (TL) peak of metamorphic quartzes was investigated. • Comparable differences were seen between low and high dose levels. • AD and CGCD methods were used

Metamorphic distributed Bragg reflectors for the 1440–1600 nm spectral range: Epitaxy, formation, and regrowth of mesa structures

International Nuclear Information System (INIS)

Egorov, A. Yu.; Karachinsky, L. Ya.; Novikov, I. I.; Babichev, A. V.; Berezovskaya, T. N.; Nevedomskiy, V. N.

2015-01-01

It is shown that metamorphic In 0.3 Ga 0.7 As/In 0.3 Al 0.7 As distributed Bragg reflectors (DBRs) with a reflection band at 1440–1600 nm and a reflectance of no less than 0.999 can be fabricated by molecular beam epitaxy (MBE) on a GaAs substrate. It is demonstrated that mesa structures formed from metamorphic DBRs on a GaAs substrate can be regrown by MBE and microcavities can be locally formed in two separate epitaxial processes. The results obtained can find wide application in the fabrication of vertical-cavity surface-emitting lasers (VCSELs) with a buried tunnel junction

Vapor flux and recrystallization during dry snow metamorphism under a steady temperature gradient as observed by time-lapse micro-tomography

Directory of Open Access Journals (Sweden)

B. R. Pinzer

2012-10-01

Full Text Available Dry snow metamorphism under an external temperature gradient is the most common type of recrystallization of snow on the ground. The changes in snow microstructure modify the physical properties of snow, and therefore an understanding of this process is essential for many disciplines, from modeling the effects of snow on climate to assessing avalanche risk. We directly imaged the microstructural changes in snow during temperature gradient metamorphism (TGM under a constant gradient of 50 K m⁻¹, using in situ time-lapse X-ray micro-tomography. This novel and non-destructive technique directly reveals the amount of ice that sublimates and is deposited during metamorphism, in addition to the exact locations of these phase changes. We calculated the average time that an ice volume stayed in place before it sublimated and found a characteristic residence time of 2–3 days. This means that most of the ice changes its phase from solid to vapor and back many times in a seasonal snowpack where similar temperature conditions can be found. Consistent with such a short timescale, we observed a mass turnover of up to 60% of the total ice mass per day. The concept of hand-to-hand transport for the water vapor flux describes the observed changes very well. However, we did not find evidence for a macroscopic vapor diffusion enhancement. The picture of {temperature gradient metamorphism} produced by directly observing the changing microstructure sheds light on the micro-physical processes and could help to improve models that predict the physical properties of snow.

LAS ESPECIES ARGENTINAS DEL GENERO SICYOS (CUCURBITACEAE.

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Raúl Martínez Crovetto

1964-01-01

Full Text Available El autor estudia las especies del género Sicyos que viven dentro del territorio de la República Argentina; señalando que hasta el presente se han hallado seis. Luego de una diagnosis del género, suministra una clave, descripciones y figuras de cada una de ellas, a fin de facilitar su reconocimiento. Las especies estudiadas son S. malvifolius Griseb., S. polyacanthus Cogn., S. Odanellii Mart.-Crov., S. Kunthii Cogn. (nuevo habitante para la flora argentina, S. Warmingii Cogn, S. Warmingii Cogn. var. longispina Mart.-Crov. (nueva variedad y S. ignarus Mart.-Crov. (especie nueva para la ciencia.

Regional safeguards arrangements: The Argentina-Brazil experience

International Nuclear Information System (INIS)

Marzo, M.; Gonzales, H.L.; Iskin, M.C.L.; Vicens, H.

1997-01-01

A Common System of Accounting and Control of Nuclear Material (SCCC) was established by Argentina and Brazil in July 1992. It is a full scope safeguard's system in both countries. The Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) was created to apply the SCCC. The main elements of the SCCC are presented. The main safeguards' procedures are described. A brief discussion of the inspection methodology and its impact for facility operators is performed. The safeguard's implementation from the operator's point of view is commented, taking as example a fuel fabrication plant in Argentina and a uranium enrichment plant in Brazil. (author)

La globalización y la enseñanza de la psicología en Argentina Globalization and education in psychology in Argentina

Directory of Open Access Journals (Sweden)

Hugo Klappenbach

2003-12-01

Full Text Available El trabajo aborda tres cuestiones. En primer lugar, analiza brevemente a la historia de la enseñanza de la psicología en Argentina, subrayando la importancia adquirida por el psicoanálisis en la tradición universitaria psicológica. En segundo lugar, desarrolla algunos de los estudios y algunas de las líneas de debate contemporáneo sobre formación universitaria del psicólogo, comenzando por algunos estudios clásicos en los Estados Unidos y concluyendo en la propuesta de diplomatura en psicología, actualmente en debate en los países miembros de la Unión Europea. En tercer lugar, analiza el impacto generado por la globalización en los procesos de formación del psicólogo en Argentina, especialmente a partir del impacto del llamado Mercosur educativo. En ese marco, se analiza críticamente la situación de los programas de psicología en las universidades argentinas.This paper approaches three subjects. Firstly, it briefly analyzes the history of psychology undergraduate programs of in Argentina, in which psychoanalytical bias is emphasized. Secondly, it reviews some important studies and reports concerning undergraduate programs and professional training in Psychology, beginning with some classical reports in USA, finishing with the proposal of an European Diploma in Psychology, which is now under evaluation in European countries. Thirdly, globalization effects, specially those from educational Mercosur, on teaching of psychology at undergradute programs and professional training in psychology in Argentina are analyzed. In such context, a critical report on psychology undergraduate programs in the country is reviewed.

Allamanda schottii (Apocynaceae: nueva cita para la Flora Argentina

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Julio A. Hurrell

2013-01-01

Full Text Available En este trabajo Allamanda schottii Pohl (Apocynaceae es documentada como nueva cita genérica y específica para la Flora Argentina. La especie fue hallada en la ribera del Paraná, en el norte de la provincia de Corrientes, Argentina. Se incluye su sinonimia, descripción, comentarios sobre su distribución, hábitat, fenología, biología reproductiva, nombres vulgares, usos y observaciones.

Rb-Sr dating of low-grade metamorphics in the U.S.S.R

International Nuclear Information System (INIS)

Gorokhov, I.M.; Varshavskaya, E.S.; Kutyavin, E.P.; Melnikov, N.N.

1982-01-01

Geologically well-dated low-grade metasedimentary and metavolcanic rocks from five localities have been studied using the whole-rock Rb-Sr age method. All age values obtained are younger than those suggested by stratigraphy. When whole-rock points fit either an isochron or an errorchron with low value of the mean square of weighted deviates, the slope of this line gives the age of metamorphism. (Auth.)

Metamorphic brines and no surficial fluids trapped in the detachment footwall of a Metamorphic Core Complex (Nevado-Filábride units, Betics, Spain)

Science.gov (United States)

Dyja-Person, Vanessa; Tarantola, Alexandre; Richard, Antonin; Hibsch, Christian; Siebenaller, Luc; Boiron, Marie-Christine; Cathelineau, Michel; Boulvais, Philippe

2018-03-01

The ductile-brittle transition zone in extensional regimes can play the role of a hydrogeological barrier. Quartz veins developed within an orthogneiss body located in the detachment footwall of a Metamorphic Core Complex (MCC) in the Nevado-Filábride units (Betics, Spain). The detachment footwall is composed mainly of gneisses, schists and metacarbonates from the Bédar-Macael sub-unit. Schist and metacarbonate bodies show evidence of ductile deformation at the time the gneiss was already undergoing brittle deformation and vein opening during exhumation. The vein system provides the opportunity to investigate the origin, composition and PVTX conditions of the fluids that circulated in the detachment footwall while the footwall units were crossing the ductile-brittle transition. The analysis of fluid inclusions reveals the presence of a single type of fluid: 30-40 mass% NaCl > KCl > CaCl2 > MgCl2 brines, with trace amounts of CO2 and N2 and tens to thousands of ppm of metals such as Fe, Sr, Li, Zn, Ba, Pb and Cu. δDfluid values between -39.8 and -16.7‰ and δ18Ofluid values between 4.4 and 11.7 ± 0.5‰ show that the brines have undergone protracted interaction with the host orthogneissic body. Coupled salinity and Cl/Br ratios (200 to 4400) indicate that the brines originate from dissolution of Triassic metaevaporites by metamorphic fluids variably enriched in Br by interaction with graphitic schists. This study highlights the absence of any record of surficial fluids within the veins, despite the brittle deformation conditions prevailing in this orthogneiss body. The fact that fluids from the detachment footwall were isolated from surficial fluid reservoirs may result from the presence of overlying schists and metacarbonates that continued to be affected by ductile deformation during vein formation in the gneiss, preventing downward circulation of surface-derived fluids.

Nota sobre el género Imperata (Poaceae, Panicoideae, Sacchareae) en Argentina

OpenAIRE

Peichoto, Myriam Carolina

2017-01-01

En este trabajo se confirma la presencia de Imperata tenuis en Argentina. Se presenta una ilustración, material de referencia y un mapa de su distribución geográfica en el sur de Sudamérica. Se incluye una clave para identificar las especies del género Imperata presentes en la Argentina. This work confirms the presence of Imperata tenuis in Argentina, and includes an illustration, reference material, a map showing its geographic distribution in southern South America, and a key to identi...

Horizontalidad, autogestión y protagonismo en Argentina

OpenAIRE

Marina Sitrin

2010-01-01

Este artículo trata los movimientos sociales autónomos que surgieron después de la crisis económica y la posterior rebelión popular en Argentina en diciembre de 2001. Los movimientos autónomos en la Argentina, como tantos movimientos en el mundo de hoy, son movimientos basados en la creación de nuevas relaciones sociales y comunidades ahora, al mismo tiempo que proyectan nuevas sociedades y las relaciones en y para el futuro. Son movimientos con una concepción diferente del tiempo y el espaci...

Aphanes arvensis (Rosaceae) en el extremo nordeste de la Argentina

OpenAIRE

Gustavo Hildt; Héctor A. Keller

2017-01-01

Se menciona por primera vez para el nordeste argentino a una hierba adventicia en el nuevomundo. La especie es ilustrada mediante fotografías Fil: Hildt, Gustavo. Universidad Nacional de Misiones; Argentina Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

Geology of uranium vein deposits (including Schwartzwalder Mine) in Proterozoic metamorphic rocks, Front Range, Colorado

International Nuclear Information System (INIS)

Voto, R.H. de; Paschis, J.A.

1980-01-01

The Schwartzwalder uranium deposit is one of many uranium vein occurrences in the Lower Proterozoic metamorphic rocks of the Front Range, Colorado. The principal veins of significant uranium content occur marginal to the Colorado Mineral Belt; are localized by structural dilation zones, vein junctions, fault deflections or branching; and occur dominantly within or at the contact of certain preferred metamorphic-stratigraphic units, particularly the siliceous, garnetiferous gneisses, where these rock units are broken by faults and fractures associated with the north-northwest-trending throughgoing faults. Uranium at the Schwartzwalder mine occurs primarily as open-space brecciated vein filling along the steeply west-dipping Illinois vein and numerous east-dipping subsidiary veins where they cut preferred metamorphic host rocks that are tightly folded. Uraninite occurs with molybdenite, adularia, jordisite, ankerite, pyrite, base-metal sulphides, and calcite in vein-filling paragenetic sequence. Minor wall-rock alteration is mainly hematite alteration and bleaching. Vertical relief on the developed ore deposit is 900 metres and still open-ended at depth. No vertical zonation of alteration, vein mineralogy, density of the subsidiary veins, or ore grade has been detected. The Schwartzwalder uranium deposit is of substantial tonnage (greater than 10,000 metric tons of U 3 O 8 ) and grade (averaging 0.57% U 3 O 8 ). Structural mapping shows that the Illinois vein-fault is a Proterozoic structure. Discordant Proterozoic (suggested) and Laramide dates have been obtained from Schwartzwalder ore. The data suggest, therefore, a Proterozoic ancestry of this heretofore presumed Laramide (Late Cretaceous-Early Tertiary) hydrothermal uranium deposit. The authors suggest a polygenetic model for the origin of the Schwartzwalder uranium deposit

Capturing latecomer advantages in the adoption of biofuels: The case of Argentina

International Nuclear Information System (INIS)

Mathews, John A.; Goldsztein, Hugo

2009-01-01

Although Argentina came late to the biofuels revolution, a series of measures taken recently at federal and provincial government level have created new opportunities. New federal laws on biofuels promotion have sparked an investment boom. The main activity has been in the biodiesel sector-partly because diesel is the dominant fuel sector in Argentina, and partly because the country had already engineered a soy revolution over the past 15 years, becoming the world's largest exporter of soy oil and soy meal. Biodiesel allows this revolution to be extended-from soy as foodstuff to soy as fuelstock. The biodiesel revolution now underway promises to extend Argentina's latecomer advantages by combining greater scale and lower costs with introduced technical innovations such as genetically modified crops and no-till farming. In this way, Argentina can be seen to be demonstrating the superiority of biofuel production in countries of the South over the conditions obtaining in countries of the North-including superior resources availability, superior energetics and lower costs. Whereas Brazil has demonstrated its superiority in sugarcane-based ethanol, Argentina is about to demonstrate its superiority in soy-based biodiesel

Characterization of agua de Ramon marbles, Cordoba Province, Argentina; Caracterizacion de los marmoles de agua de Ramon Provincia de Cordoba, Argentina

Energy Technology Data Exchange (ETDEWEB)

Tourn, S; Castro, L. [Departamento de Ciencias Geologicas, Facultad de Ciencias Exactas y Naturales, Universidad de buenos Aires, (Argentina)]. E mail: selvia@fcen.uba.ar, lilianacastro@fibertel.com.ar

2004-09-01

Agua de Ramon district is located in the NW of Cordoba, Argentina, between 3 49' and 30{sup 0}52' S and 65{sup 0}21' and 65{sup 0}24' W, in the Eastern Pampean Range setting. It was a very important tungsten district until the end of 1950'decade when tungsten mining became of no economic interest. The objective is to report for the first time the petrological, mineralogical and geochemical characteristics of several marble lenses located in the sourthern of the area. Marble outcrops are lenticular ranging from 1 m to 80 m in length and 0.50 m to 20 m width. They appear massive, fine-grained and in light colors (white, pale green, very light brown and pale gray). These last varieties show a distinct banded structure due to little differences in color. These marbles are mainly composed of magnesian calcite accompanied by minor amounts of dolomite, forsterite, humite group minerals, tremolite, talc, serpentine and clinochlore, and scheelite, sphene, apatite and opaque minerals like hematite, magnetite, illmenite, pirrothite and pyrite as accessory minerals. Major chemical analyses indicate a relatively high SiO2 and MgO content, and minor CaO, in comparison with marbles of this type. Mineral paragenesis was useful to evaluate metamorphism conditions in this area. [Spanish] El distrito Agua de Ramon se localiza en el departamento de Minas al noroeste de la provincia de Cordoba, Argentina, entre los paralelos 30{sup 0}49' y 30{sup 0}52' de latitud sur y los meridianos 65{sup 0}21' y 65{sup 0}24' de longitud oeste, en el ambito de las Sierras Pampeanas Orientales. En el pasado constituyo un importante distrito de explotacion wolframifera, pero dicha actividad se halla paralizada desde fines de la decada del '50. El objetivo de este trabajo es hacer conocer por primera vez las caracteristicas de los marmoles localizados en el sector sur desde el punto de vista petrografico, mineralogico y geoquimico de manera que permita realizar un analisis petrogenetico. Los cuerpos son

U-Th-PbT Monazite Gechronology in the South Carpathian Basement: Variscan Syn-Metamorphic Tectonic Stacking and Long-Lasting Post-Peak Decompressional Overprints

Science.gov (United States)

Săbău, G.; Negulescu, E.

2012-12-01

Dating metamorphic events appears to be unsatisfactorily addressed by most of the widely-employed and otherwise accurate and productive isotopic techniques, because the phases and systems investigated do not directly relate to the metamorphic events themselves. An adequate answer to this challenge is instead provided by microprobe-assisted chemical U-Th-PbT monazite geochronology, by its spatial resolution, truly in situ character and the possibility to reference analyses against well-defined textural environments and features, as well as a qualitative timeframe derived therefrom. Though chemical U-Th-PbT monazite geochronology is increasingly applied to seek answers ranging form a general characterization to fine details of the thermotectonic evolution of magmatic and metamorphic rocks, there are so far, unlike in the case of isotopic geochronological methods, no clearly defined standard analytical and data processing protocols. Two main reasons for this have to be mentioned, namely that chemical U-Th-PbT chronology is actually a proxy for isotopic geochronology, and the quantification of the errors and their propagation cannot be directly assessed because apparent ages are related to the measured element concentrations by an implicit function, the law of radioactive decay. Current approaches rely on treating calculated individual age values as primary data, a priori grouping of analyses supposed (and subsequently tested) to be coeval, and their statistical processing in order to obtain age values. An alternative approach we applied in basement units of the South Carpathians consists in an explicit approximation of the age formula and associated errors propagated from element concentrations to age values, and individual treatment of each age datum. The separation of the age clusters from the overall age spectrum of each sample was operated by tracing the variations of the normalized age gradient on the age spectrum sorted by increasing age values, and fine

First record in Argentina of Drepanosiphum oregonense Granovsky (Hemiptera: Aphididae) found on maples (Sapindaceae)

OpenAIRE

Ortego, Jaime; Olave, Anabel; Mier Durante, Milagros Pilar

2014-01-01

Se informa del hallazgo del áfido Drepanosiphum oregonense Granovsky (Hemiptera: Aphididae) sobre árboles de Acer pseudoplatanus y A. campestre (Sapindaceae) en Argentina lo que constituye el primer registro de la especie y del género Drepanosiphum Koch en Argentina y el segundo en Sudamérica. The finding in Argentina of the aphid Drepanosiphum oregonense on "maple tree" Acer pseudoplatanus ...

Potential of exchange of electric power between the electric systems of Brazil and Argentina; Potencial de intercambio de energia eletrica entre os sistemas eletricos do Brasil e da Argentina

Energy Technology Data Exchange (ETDEWEB)

Zanette, Andre Luiz [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

2010-07-01

Integration of power generation and transmission systems can provide a better utilization of energy resources and increase systems reliability. Given that Brazilian interconnection with Argentina, which represents the major Brazilian interconnection with neighboring countries, is used basically in winter months or in situations of unfavorable hydrology, this paper aims to demonstrate that power exchange between these two countries can be much higher than currently observed, resulting in greater benefits for producers and consumers of electricity in both countries, and that these benefits can also be obtained through better use of existing and planned interconnections between South American countries. To estimate the potential for power exchange between the electrical systems of Brazil and Argentina, three sets of simulations using the Brazilian Energy Plan (PDE 2010-2019) deck for Newave model, available from EPE, were made. These simulations consider the possibility that: (i) electricity is exported from Brazil to Argentina (II) electricity is imported from Argentina and (III) electricity is exchanged in both directions. The simulation results indicate that, despite rising operational marginal costs, significant amounts of electricity can be exported to Argentina at relatively low prices, depending on hydrological conditions. Moreover, the possibility of electricity imports from Argentina can reduce the operational costs of Brazilian system, as well as minimizing the risk of shortages. This work shows that the interconnections between Brazil and Argentina may be better used to benefit producers and consumers in both countries. Therefore, it is necessary to define an effective contractual and operational model for power trading and electricity transfer between these countries with the objective of promoting stability and mutual trust. Finally, studies to evaluate the potential for electricity exchange between South American countries are specially important

Potential of exchange of electric power between the electric systems of Brazil and Argentina; Potencial de intercambio de energia eletrica entre os sistemas eletricos do Brasil e da Argentina

Energy Technology Data Exchange (ETDEWEB)

Zanette, Andre Luiz [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

2010-07-01

Integration of power generation and transmission systems can provide a better utilization of energy resources and increase systems reliability. Given that Brazilian interconnection with Argentina, which represents the major Brazilian interconnection with neighboring countries, is used basically in winter months or in situations of unfavorable hydrology, this paper aims to demonstrate that power exchange between these two countries can be much higher than currently observed, resulting in greater benefits for producers and consumers of electricity in both countries, and that these benefits can also be obtained through better use of existing and planned interconnections between South American countries. To estimate the potential for power exchange between the electrical systems of Brazil and Argentina, three sets of simulations using the Brazilian Energy Plan (PDE 2010-2019) deck for Newave model, available from EPE, were made. These simulations consider the possibility that: (i) electricity is exported from Brazil to Argentina (II) electricity is imported from Argentina and (III) electricity is exchanged in both directions. The simulation results indicate that, despite rising operational marginal costs, significant amounts of electricity can be exported to Argentina at relatively low prices, depending on hydrological conditions. Moreover, the possibility of electricity imports from Argentina can reduce the operational costs of Brazilian system, as well as minimizing the risk of shortages. This work shows that the interconnections between Brazil and Argentina may be better used to benefit producers and consumers in both countries. Therefore, it is necessary to define an effective contractual and operational model for power trading and electricity transfer between these countries with the objective of promoting stability and mutual trust. Finally, studies to evaluate the potential for electricity exchange between South American countries are specially important

76 FR 51934 - Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments

Science.gov (United States)

2011-08-19

... acknowledged Argentina's history of successful Medfly control efforts, but stated that APHIS should not relax...] Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments AGENCY: Animal and Plant... received a request from the Government of Argentina to recognize additional areas as pest- free areas for...

CellDyM: A room temperature operating cryogenic cell for the dynamic monitoring of snow metamorphism by time-lapse X-ray microtomography

Science.gov (United States)

Calonne, N.; Flin, F.; Lesaffre, B.; Dufour, A.; Roulle, J.; Puglièse, P.; Philip, A.; Lahoucine, F.; Geindreau, C.; Panel, J.-M.; Roscoat, S. Rolland; Charrier, P.

2015-05-01

Monitoring the time evolution of snow microstructure in 3-D is crucial for a better understanding of snow metamorphism. We, therefore, designed a cryogenic cell that precisely controls the experimental conditions of a sample while it is scanned by X-ray tomography. Based on a thermoelectrical regulation and a vacuum insulation, the cell operates at room temperature. It is, thus, adaptable to diverse scanners, offering advantages in terms of imaging techniques, resolution, and speed. Three-dimensional time-lapse series were obtained under equitemperature and temperature gradient conditions at a 7.8 μm precision. The typical features of each metamorphism and the anisotropic faceting behavior between the basal and prismatic planes, known to occur close to -2°C, were observed in less than 30 h. These results are consistent with the temperature fields expected from heat conduction simulations through the cell. They confirm the cell's accuracy and the interest of relatively short periods to study snow metamorphism.

An evolutionary approach to mania studying Sardinian immigrants to Argentina.

Science.gov (United States)

Carta, Mauro G; Perra, Alessandra; Atzeni, Michela; D'Oca, Silvia; Moro, Maria F; Kurotschka, Peter K; Moro, Daniela; Sancassiani, Federica; Minerba, Luigi; Brasesco, Maria V; Mausel, Gustavo; Nardi, Antonio E; Tondo, Leonardo

2017-01-01

To ascertain lifetime prevalence of positivity to a screening questionnaire for bipolar disorders (BD) in Sardinian immigrants to Argentina and residents of Sardinia and assess whether such positivity affects quality of life (QoL) in either group. Our hypothesis is that screen positivity for BD may be more frequent in immigrants. Observational study. Subjects were randomly selected from the membership lists of associations of Sardinian immigrants in Argentina. A study carried out in Sardinia using the same methodology was used for comparison. The Mood Disorder Questionnaire was used to screen for mania/hypomania and the Short-Form Health Survey-12 to measure QoL. A higher prevalence of manic/hypomanic episodes was found in Sardinian immigrants to Argentina (p immigrants to Argentina and in residents of Sardinia. To the best of our knowledge, this is the first study to show a higher lifetime prevalence of manic/hypomanic episodes in a general-population sample of individuals who migrated to a foreign country. Our results are in agreement with the hypothesis that hyperactive/novelty-seeking features may represent an adaptive substrate in certain conditions of social change.

Progress of Grid technology in Argentina: Lessons learned from EELA

International Nuclear Information System (INIS)

Dova, M. T.; Grunfeld, C.; Monticelli, F.; Tripiana, M.; Veiga, A.; Ambrosi, V.; Barbieri, A.; Diaz, J.; Luengo, M.; Macia, M.; Molinari, L.; Veonosa, P.; Zabaljauregui, M.

2007-01-01

The EELA project aimed to create a collaboration network between Europe and Latin American for training in Grid technologies and the deployment of a pilot Grid infrastructure for e-science applications. Grid computing has emerged as an important new field, and its development in Argentina is particularly important for a number of reasons, such as that Argentina has recently joined the ATLAS collaboration at CERN and the increasing interest in future biomedical applications. The potential of GRID technology is well known, however, its adoption is not a trivial task as it requires significant investment in several areas. In this paper, the achievements and progress in Argentina through close collaboration with EELA are presented. Among these are the deployment of a Grid Certification Authority infrastructure that is a crucial component in the activities of the e-Science community in the country; the deployment, integration and validation of a small local EELA node; installation and running of an analysis ATLAS application on the EELA infrastructure. The experience gained in participating in EELA dissemination events also allowed us to actively promote the GRID and training for its use different target audiences in Argentina and in LA. (Author)

Nuclear Data in Argentina (1992 -1993)

International Nuclear Information System (INIS)

Ricabarra, G. H.

1993-03-01

A progress report of nuclear data research in Argentina is given for the years 1992/1993, including the WIMS nuclear data library update project, and measurements and evaluations of selected neutron induced nuclear reactions. (author)

Uranium mineralization possibilities in metamorphic Massif of Isla de Juventud, Cuba

International Nuclear Information System (INIS)

Gongora Dominguez, L.E.; Llanes Castro, A.I.; Pena Fortes, B.; Capote Rodriguez, G.

1996-01-01

The geologic and metallogenic characteristic of the metamorphic Massif shows the presence of possible uranium vein type mineralization as a result of a hidrotermal genetic process. Metalliferous fluids rising along the fault system were responsible for the deposition of the uranium in the reduction zones, i.e. presence of pyrite, organic matter and others. This type of uranium minerization is proposed for the Bibijagua area and for the Revolucion and Lela area the same type is expected. The gamma spectrometric analysis was used to evaluate the geological samples

Nuevas citas de monocotiledóneas adventicias para la Argentina New records of adventitious monocots for Argentina

Directory of Open Access Journals (Sweden)

Julio A. Hurrell

2009-12-01

Full Text Available Este trabajo incluye cinco nuevos registros de monocotiledóneas adventicias para la Argentina: Aloe ciliaris Haw. (Asphodelaceae, Aspidistra elatior Blume (Convallariaceae, Sansevieria trifasciata Prain (Dracaenaceae, Phormium tenax J. R. Forst. & G. Forst. (Hemerocallidaceae y Ornithogalum arabicum L. (Hyacinthaceae, pertenecientes al orden Asparagales. También incluye una evaluación del estado actual de estas especies, en relación al proceso de naturalización: escapadas de cultivo ocasionales, naturalizadas.This paper includes five new records of adventitious monocots for Argentina: Aloe ciliaris Haw. (Asphodelaceae, Aspidistra elatior Blume (Convallariaceae, Sansevieria trifasciata Prain (Dracaenaceae, Phormium tenax J. R. Forst. & G. Forst. (Hemerocallidaceae and Ornithogalum arabicum L. (Hyacinthaceae, belonging to order Asparagales. Also includes an evaluation of its status in the naturalization process: casual alien, naturalized.

QUBIC in Argentina

Science.gov (United States)

García, B.; Harari, D.; Etchegoyen, A.; Medina, M. C.; Romero, G. E.; Qubic Collaboration

2017-10-01

QUBIC (QU Bolometric Interferometer for Cosmology) is an experimental cosmology project to measure the modes in the polarization of the cosmic background radiation (CBR), the fossil relic that reveals the properties at the Universe 380,000 years after the Planck Era. Discovery of the CBR in 1964 and measurement of tiny temperature anisotropies in 1992 were major breakthroughs in our understanding of the Universe. The next challenge is to measure the polarization of the CBR accurately enough to detect modes that would reveal the existence of primordial gravitational waves produced in the first stages of the Planck Era and probe inflation theory, that assumes an accelerated expansion during the first seconds. The mode signal is however extremely weak and its measurement requires complex instruments. The QUBIC collaboration has developed the concept of interferometric bolometry, that brings together the sensitivity of bolometric detectors with the control of systematic effects provided by interferometry. QUBIC is an international collaboration involving several universities and laboratories in France, Italy, United Kingdom and USA. Recently, Argentina has suggested Alto Chorrillo (Salta), as candidate site for the installation of the experiment, next to the LLAMA site. Here we describe the scientific objectives and the main features of the experiment and we detail the process through which the international collaboration decided to install in Argentina its first module as well as the challenges for our country in this project.

The Influence of Positivism in the Nineteenth Century Astronomy in Argentina

Science.gov (United States)

Santilli, Haydee; Cornejo, Jorge Norberto

2013-01-01

In this paper we analyze the influence of positivism in Argentina astronomical culture in the nineteenth century. We did the analysis from two dimensions, scientific knowledge development and science teaching. Because Argentina was a very young country at that time, it was of singular importance, not only the development of scientific knowledge…

Horticulture in Argentina: a productive alternative with great potential

Directory of Open Access Journals (Sweden)

Ana Maria Castagnino

2011-12-01

Full Text Available Horticulture in Argentina is an activity with great potential whose history has mainly been driven by Italian immigrants who arrived during the last two centuries. It is a valuable complement for traditional primary productions on which the country is focused with more than 30 millions of cultivated hectares and different agro-climatic conditions that characterize the different horticultural regions distributed throughout the country. The aim of this article is to give a panorama of the history, reality and perspectives in Argentina of an activity that is an opportunity for producers and entrepreneurs interested in it. Due to its characteristics, horticulture generates and dynamizes employment with great importance for regional economies. The proportion between vegetables and fruit produced and commercialized in Argentina is 63 and 34% respectively. Horticultural products for exportation largely are garlic, onion and beans. Concerning the most commercialized vegetables in Argentina, potato, tomato, onion, squash, lettuce, pepper, marrow and sweet potato stand out, whereas orange, tangerine, apple, banana, lemon, pear, grape and grapefruit may be highlighted among fruit. At present, the main challenge of the Argentinian horticultural sector is given not only by the possibilities of productive diversification and the expansion of the productive area but also of the technological level optimization, the application of quality norms and the agro-industry growth.

Sistema de salud de Argentina The health system of Argentina

Directory of Open Access Journals (Sweden)

Mariana Belló

2011-01-01

Full Text Available En este artículo se describe el sistema de salud de Argentina, que está compuesto por tres sectores: público, de seguridad social y privado. El sector público está integrado por los ministerios nacional y provincial, y la red de hospitales y centros de salud públicos que prestan atención gratuita a toda persona que lo demande, fundamentalmente a personas sin seguridad social y sin capacidad de pago. Se financia con recursos fiscales y recibe pagos ocasionales de parte del sistema de seguridad social cuando atiende a sus afiliados. El sector del seguro social obligatorio está organizado en torno a las Obras Sociales (OS, que aseguran y prestan servicios a los trabajadores y sus familias. La mayoría de las OS operan a través de contratos con prestadores privados y se financian con contribuciones de los trabajadores y patronales. El sector privado está conformado por profesionales de la salud y establecimientos que atienden a demandantes individuales, a los beneficiarios de las OS y de los seguros privados. Este sector también incluye entidades de seguro voluntario llamadas Empresas de Medicina Prepaga que se financian sobre todo con primas que pagan las familias y/o las empresas. En este trabajo también se describen las innovaciones recientes en el sistema de salud, incluyendo el Programa Remediar.This paper describes the health system of Argentina.This system has three sectors: public, social security and private.The public sector includes the national and provincial ministries as well as the network of public hospitals and primary health care units which provide care to the poor and uninsured population. This sector is financed with taxes and payments made by social security beneficiaries that use public health care facilities. The social security sector or Obras Sociales (OS covers all workers of the formal economy and their families. Most OS operate through contracts with private providers and are financed with payroll

La migracion internacional en Argentina hacia 2010

Directory of Open Access Journals (Sweden)

Laura Calvelo

Full Text Available El artículo presenta los principales lineamientos de la migración internacional en Argentina hacia el año 2010, con detenimiento en el período 2000-2010. En el caso de la inmigración no nativa se basa en información de los censos nacionales de población 2001 y 2010. En el caso de la migración internacional de la población nativa de Argentina el análisis se sustenta en información de censos extranjeros hasta la ronda 2000 y en otras fuentes de datos de los principales países de destino hasta 2010 (Estados Unidos y España.

Timing of metamorphism of the Lansang gneiss and implications for left-lateral motion along the Mae Ping (Wang Chao) strike-slip fault, Thailand

Science.gov (United States)

Palin, R. M.; Searle, M. P.; Morley, C. K.; Charusiri, P.; Horstwood, M. S. A.; Roberts, N. M. W.

2013-10-01

The Mae Ping fault (MPF), western Thailand, exhibits dominantly left-lateral strike-slip motion and stretches for >600 km, reportedly branching off the right-lateral Sagaing fault in Myanmar and extending southeast towards Cambodia. Previous studies have suggested that the fault assisted the large-scale extrusion of Sundaland that occurred during the Late Eocene-Early Oligocene, with a geological offset of ˜120-150 km estimated from displaced high-grade gneisses and granites of the Chiang Mai-Lincang belt. Exposures of high-grade orthogneiss in the Lansang National Park, part of this belt, locally contain strong mylonitic textures and are bounded by strike-slip ductile shear zones and brittle faults. Geochronological analysis of monazite from a sample of sheared biotite-K-feldspar orthogneiss suggests two episodes of crystallization, with core regions documenting Th-Pb ages between c. 123 and c. 114 Ma and rim regions documenting a significantly younger age range between c. 45-37 Ma. These data are interpreted to represent possible magmatic protolith emplacement for the Lansang orthogneiss during the Early Cretaceous, with a later episode of metamorphism occurring during the Eocene. Textural relationships provided by in situ analysis suggest that ductile shearing along the MPF occurred during the latter stages of, or after, this metamorphic event. In addition, monazite analyzed from an undeformed garnet-two-mica granite dyke intruding metamorphic units at Bhumipol Lake outside of the Mae Ping shear zone produced a Th-Pb age of 66.2 ± 1.6 Ma. This age is interpreted to date the timing of dyke emplacement, implying that the MPF cuts through earlier formed magmatic and high-grade metamorphic rocks. These new data, when combined with regional mapping and earlier geochronological work, show that neither metamorphism, nor regional cooling, was directly related to strike-slip motion.

Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera,Apidae

Directory of Open Access Journals (Sweden)

Moysés Elias-Neto

2013-06-01

Full Text Available Expression profile of a Laccase2 encoding gene during the metamorphic molt in Apis mellifera (Hymenoptera, Apidae. Metamorphosis in holometabolous insects occurs through two subsequent molting cycles: pupation (metamorphic molt and adult differentiation (imaginal molt. The imaginal molt in Apis mellifera L. was recently investigated in both histological and physiological-molecular approaches. Although the metamorphic molt in this model bee is extremely important to development, it is not well-known yet. In the current study we used this stage as an ontogenetic scenario to investigate the transcriptional profile of the gene Amlac2, which encodes a laccase with an essential role in cuticle differentiation. Amlac2 expression in epidermis was contrasted with the hemolymph titer of ecdysteroid hormones and with the most evident morphological events occurring during cuticle renewal. RT-PCR semiquantitative analyses using integument samples revealed increased levels of Amlac2 transcripts right after apolysis and during the subsequent pharate period, and declining levels near pupal ecdysis. Compared with the expression of a cuticle protein gene, AmelCPR14, these results highlighted the importance of the ecdysteroid-induced apolysis as an ontogenetic marker of gene reactivation in epidermis for cuticle renewal. The obtained results strengthen the comprehension of metamorphosis in Apis mellifera. In addition, we reviewed the literature about the development of A. mellifera, and emphasize the importance of revising the terminology used to describe honey bee molting cycles.

The genera Boiruna and Clelia (serpentes: pseudoboini in Paraguay and Argentina

Directory of Open Access Journals (Sweden)

Norman J. Scott Jr.

2006-01-01

Full Text Available Snakes of the pseudoboine genera Clelia, which is probably polyphyletic, and Boiruna are distributed from southern Argentina, southern Brazil, and Uruguay northwards into central México. Six members occur in Paraguay and Argentina: B. maculata, Clelia bicolor, C. clelia, C. plumbea, C. quimi, and C. rustica. Historically, there has been taxonomic confusion among the larger species (B. maculata, C. clelia, C. plumbea, and C. rustica and between the small species (C. bicolor and C. quimi. All of the species except C. rustica have distinct ontogenetic color changes. Species can be distinguished on the bases of size, color, hemipenial spines, and loreal, supralabial, and ventral scale counts. Much of the morphological evolutionary differentiation in Boiruna and Clelia seems to have taken place in the snout region, as evidenced by the differing proportions of the scales of the loreal region. Boiruna maculata has the widest ecological amplitude. It is broadly distributed in most vegetation types north of the 38th parallel in central Argentina, being absent only from the deltaic sediments of Buenos Aires Province, Argentina and the broad valleys and rolling hills of eastern Paraguay. Clelia bicolor is most common in the Paraguay and Paraná river valleys, with a few records from the Andean foothills in northern Argentina. Clelia clelia is distributed along the Río Paraguay and the lower Paraná, and is also found throughout much of eastern Paraguay. Clelia plumbea is apparently parapatric with C. clelia along the Río Paraná in southeastern Paraguay and Misiones Province, Argentina. The ranges of C. quimi to the east and C. bicolor in the west about in this same region without apparent overlap. There are no vouchered records of Clelia rustica from Paraguay. In Argentina, it is a species of temperate climates; north of the 30th parallel, it occurs in the Andean foothills and the wet forests of Misiones Province. Southwards, it is widely distributed

WTO: US and Argentina settle dispute over patents and data protection.

Science.gov (United States)

Elliott, Richard

2002-12-01

In May 2000, supplementing an earlier complaint filed in May 1999, the US filed a complaint against Argentina, alleging that its patent laws violate the World Trade Organization's Agreement on Trade-Related Aspects of Intellectual Property (the TRIPS Agreement). The gist of the US complaint was that Argentina's law failed to provide: (1) adequate protection against "unfair" commercial use of undisclosed test data submitted in order to get market approval of pharmaceutical products; (2) certain safeguards for compulsory licences on an invention granted on the basis of inadequate working by the patent holder; and (3) adequate measures to prevent infringements of patent rights. The US also alleged that Argentina denies certain exclusive rights of patent holders, such as the exclusive right to import the patented product into the country. At the end of May 2002, the US and Argentina notified the WTO that they had reached a "mutually agreed solution," without prejudice to their respective rights and obligations under WTO agreements, and the US has withdrawn its complaint.

Breve historia de los refugiados en Argentina durante el siglo XX

Directory of Open Access Journals (Sweden)

María Paula Cicogna

2009-12-01

Full Text Available Argentina ha sostenido, desde la letra escrita de la Constitución Nacional, ser un país receptor de inmigración, aunque en los hechos ha demostrado lo contrario. A pesar de ello, durante el siglo XX se instalaron grupos de exiliados, solicitantes de refugio y refugiados de las más diversas nacionalidades. Este artículo mostrará los contingentes que conformaron el mapa multicultural de la Argentina a partir del desarrollo de una cronología creada a en base a los trabajos de investigación que analizaron el establecimiento de las diversas comunidades._________________ABSTRACT:According to National Constitution Argentina has been an open doors country to immigration, although it has demonstrated the opposite. In spite of it, during XX century groups of exiles, asylum seekers and refugees of different nationalities settled in the country. Based in a chronology created from varied researches which analyzed the establishment of the diverse communities this article will show the groups that shape the multicultural map of Argentina.

K-Ar dating celadonite: A contribution to timing of a very low-grade metamorphism in the Central Andes of Chile

International Nuclear Information System (INIS)

Belmar, M; Schmidt, S.; Frey, M

2001-01-01

Clay minerals have been used in several studies to date very low-grade metamorphism processes and hydrothermal episodes. The technique of using the K-Ar isotopic dating was demonstrated by many authors (e.g. Hunziker et al., 1986; Clauer et al., 1995; Kirschner et al 1995; Zhao et al., 1997; Glasmacher et al., 2001). White mica and illitic materials of different size are usually analysed, whereasceladonite mineral with high potassium content has been low developed and few data are published. Successful dating of continental Andean celadonite could mean that is possible to date the very low-grade metamorphism (zeolites facies) in which celadonites are very often observed (au)

NREL technical assistance to Argentina

Energy Technology Data Exchange (ETDEWEB)

Lilienthal, P. [National Renewable Energy Lab., Golden, CO (United States)

1997-12-01

This paper describes assistance to Argentina from the National Renewable Energy Laboratory which has touched on four programs: tariff analysis for rural concessions programs; wind/diesel hybrid retrofits in Patagonia; small hybrid systems designs for rural schools; an assessment of wind resources. The paper expands briefly on the first two points.

A Cambrian mixed carbonate-siliciclastic platform in SW Gondwana: evidence from the Western Sierras Pampeanas (Argentina) and implications for the early Paleozoic paleogeography of the proto-Andean margin

Science.gov (United States)

Ramacciotti, Carlos D.; Casquet, César; Baldo, Edgardo G.; Galindo, Carmen; Pankhurst, Robert J.; Verdecchia, Sebastián O.; Rapela, Carlos W.; Fanning, Mark

2018-05-01

The Western Sierras Pampeanas (WSP) of Argentina record a protracted geological history from the Mesoproterozoic assembly of the Rodinia supercontinent to the early Paleozoic tectonic evolution of SW Gondwana. Two well-known orogenies took place at the proto-Andean margin of Gondwana in the Cambrian and the Ordovician, i.e., the Pampean (545-520 Ma) and Famatinian (490-440 Ma) orogenies, respectively. Between them, an extensive continental platform was developed, where mixed carbonate-siliciclastic sedimentation occurred. This platform was later involved in the Famatinian orogeny when it underwent penetrative deformation and metamorphism. The platform apparently extended from Patagonia to northwestern Argentina and the Eastern Sierras Pampeanas, and has probable equivalents in SW Africa, Peru, and Bolivia. The WSP record the outer (deepest) part of the platform, where carbonates were deposited in addition to siliciclastic sediments. Detrital zircon U-Pb SHRIMP ages from clastic metasedimentary successions and Sr-isotope compositions of marbles from the WSP suggest depositional ages between ca. 525 and 490 Ma. The detrital zircon age patterns further suggest that clastic sedimentation took place in two stages. The first was sourced mainly from re-working of the underlying Neoproterozoic metasedimentary rocks and the uplifted core of the early Cambrian Pampean orogen, without input from the Paleoproterozoic Río de la Plata craton. Sediments of the second stage resulted from the erosion of the still emerged Pampean belt and the Neoproterozoic Brasiliano orogen in the NE with some contribution from the Río de la Plata craton. An important conclusion is that the WSP basement was already part of SW Gondwana in the early Cambrian, and not part of the exotic Precordillera/Cuyania terrane, as was previously thought.

Preliminary study of the uranium favorability of granitic and contact-metamorphic rocks of the Owens Valley area, Inyo and Mono Counties, California, and Esmeralda and Mineral Counties, Nevada

International Nuclear Information System (INIS)

Cupp, G.M.; Mitchell, T.P.

1978-01-01

Granitic and contact-metamorphic rocks of the Owens Valley area were sampled to determine their favorability for uranium. Uranium deposits associated with these rocks were examined to determine the mode of occurrence. Metamorphic rocks near contacts with intrusive rocks include skarns, schists, quartzites, metaconglomerates, hornfels, gneisses, and metavolcanics. The grade of contact metamorphism ranges from slight to intense, depending upon the distance from the intrusive contact. The average U 3 O 8 content of the metamorphic rock samples is 3 ppM. Metamorphic rock samples in a roof pendant at the Claw prospect contain as much as 3 percent U 3 O 8 . Skarn samples from the Birch Creek pluton contain as much as 114 ppM U 3 O 8 ; those from the Santa Rita Flat pluton contain as much as 23 ppM U 3 O 8 . Most of the intrusive rocks are granite, quartz monzonite, or monzonite. Granodiorite and diorite are less common, and gabbro is rare. The average U 3 O 8 content of the crystalline rock samples is 4 ppM. Samples from a quartz-monzonite pluton east of Lone Pine, California, and quartz monzonite in the Santa Rosa Hills had maximum contents of 28 and 13 ppM U 3 O 8 , respectively. Areas of contact metamorphism and metasomatism, such as those at the Claw prospect and Birch Creek pluton, are probably the most favorable sites for uranium deposits. There are many miles of granitic and contact-metamorphic zones in which undiscovered uranium deposits may exist. Although the overall uranium content of granitic rocks appears to be low, the pluton east of Lone Pine and the Hunter Mountain pluton in the area of the Santa Rosa Hills have sufficient uranium to have acted as uranium and detrital source rocks for uranium deposits that may now be buried in Tertiary sediments in the basins around the plutons. The Claw deposit is the only known uranium deposit of a size and grade to be of possible commercial interest

RERTR activities in Argentina

International Nuclear Information System (INIS)

Adelfang, P.; Alvarez, L.; Pasqualini, E.

2002-01-01

The Atomic Energy Commission of Argentina has been an active participant of the RERTR program since 1978. An important milestone of the Argentinean RERTR program was the development and manufacturing at industrial scale of U 3 O 8 dispersed fuel and its subsequent application to the conversion of the RA-3 reactor core to LEU fuel. More recently, our activities were focused on the development of U 3 Si 2 fuel with a density of 4.8 gU/cm 3 and the improvement of the manufacturing process of this type of fuel. The program to qualify CNEA as a supplier U 3 Si 2 dispersed fuels is scheduled to finalize by mid 2003. To hasten this program the main research reactor of Argentina, the RA3, raised its power from 5 MW to 8 Mw in October this year. This is an intermediate step in the program to increase RA-3 power to 10 MW Currently, one of the main objectives is to develop and qualify the technology for the production of high-density LEU fuel elements using U-Mo alloy. An original way to produce U-Mo powder (the HMD process) was developed and its being upgraded to plant scale production. Another significant progress was the development of LEU targets for the production of 99 Mo, in the form of miniplates prepared with dispersed LEU U-Al x . The shipment to USA of 207 MTR spent fuels containing US origin highly enriched uranium, successfully carried out in the end of 2000, is another remarkable achievement of the Argentinean RERTR program. This activity was carried out in the framework of the United States Foreign Research Reactor Spent Nuclear Fuel Acceptance Program. The fuels were fabricated in Argentina and used in the RA-3 reactor from 1968 to 1987. The inventory of the shipped HEU spent fuel consisted in 166 standard assemblies and 41 control assemblies. (author)

Relative Militarization and Its Impact on Public Policy Budgetary Shifts in Argentina, 1963-1982

Science.gov (United States)

1988-07-01

Until such a time, the reader is advised to consult the extensive literature on the subject (e.g. Cavarozzi, 1983; Historia Politica Argentina , 1985...34 Desarrollo Econ6mico, V.19. (1981), "Teoria y practica del liberalismo. Politica antiinfla- cionaria y apertura economica en la Argentina 1976-1981...American Political Economy. Boulder: Westview Press. Historia Politica Argentina , 1942-1982. (1985) Buenos Aires: Editorial del Belgrano. 48 Hughes, S.W

Research on English Language Teaching and Learning in Argentina (2007-2013)

Science.gov (United States)

Porto, Melina; Montemayor-Borsinger, Ann; López-Barrios, Mario

2016-01-01

In this article we review research on English as a foreign language (EFL) teaching and learning published in Argentina between 2007 and 2013. This is the first review of a Latin American country in this series. Argentina has a century-long tradition of training EFL teachers but a comparatively shorter though fruitful history of foreign language…

A new species of Tullbergia (Collembola, Tullbergiidae) from Buenos Aires, Argentina

Science.gov (United States)

Palacios-Vargas, José G.; Martínez, Ana E. Salazar

2014-01-01

Abstract A new species of Tullbergia from Argentina is described and illustrated; it is differentiated from Tullbergia paranensis by the number of vesicles of postantennal organ, pseudocelli shape and its formulae and the number of dorsal sensilla on Ant. IV. In addition a key for the identification of the members of the family from Argentina is included. PMID:25061344

Nota sobre EL GÉNERO Imperata (Poaceae, Panicoideae, Sacchareae en Argentina

Directory of Open Access Journals (Sweden)

Myriam C. Peichoto

2013-01-01

Full Text Available En este trabajo se confirma la presencia de Imperata tenuis en Argentina. Se presenta una ilustración, material de referencia y un mapa de su distribución geográfica en el sur de Sudamérica. Se incluye una clave para identificar las especies del género Imperata presentes en la Argentina.

Research advances in contact model and mechanism configuration for nut shelling manipulation based on metamorphic method

Directory of Open Access Journals (Sweden)

Xiulan BAO

2017-04-01

Full Text Available Nuts are the important economic forest tree species of China. De-shell is the key operation of nut deep processing. There are some problems in the current nut cracking devices such as the low decorticating rate, the high nuts losses rate and nutmeat integrity problems, etc.. The foundation of force analysis is to establish contact model for nut and mechanical. The nut surface is rough and irregular, so the contact area cannot be modeled as regular shape. How to set up contact constraint model is the key problem to accomplish non-loss shelling. In order to study the shell-breaking mechanism and structural design of the nut shelling manipulation, a multi-fingered metamorphic manipulator is presented. An overview of the nut shelling technology and the contact manipulator modeling are proposed. The origin and application of metamorphic mechanisms are introduced. Then the research contents and development prospects of nut shelling manipulator are described.

Tectonic and metamorphic discontinuities in the Greater Himalayan Sequence in Central Himalaya: in-sequence shearing by accretion from the Indian plate

Science.gov (United States)

Carosi, Rodolfo

2016-04-01

The Greater Himalayan Sequence (GHS) is the main metamorphic unit of the Himalayas, stretching for over 2400 km, bounded to the South by the Main Central Thrust (MCT) and to the North by the South Tibetan Detachment (STD) whose contemporanous activity controlled its exhumation between 23 and 17 Ma (Godin et al., 2006). Several shear zones and/or faults have been recognized within the GHS, usually regarded as out of sequence thrusts. Recent investigations, using a multitechnique approach, allowed to recognize a tectonic and metamorphic discontinuity, localized in the mid GHS, with a top-to-the SW sense of shear (Higher Himalayan Discontinuity: HHD) (Carosi et al., 2010; Montomoli et al., 2013). U-(Th)-Pb in situ monazite ages provide temporal constraint of the acitivity of the HHD from ~ 27-25 Ma to 18-17 Ma. Data on the P and T evolution testify that this shear zone affected the tectono-metamorphic evolution of the belt and different P and T conditions have been recorded in the hanging-wall and footwall of the HHD. The HHD is a regional tectonic feature running for more than 700 km, dividing the GHS in two different portions (Iaccarino et al., 2015; Montomoli et al., 2015). The occurrence of even more structurally higher contractional shear zone in the GHS (above the HHD): the Kalopani shear zone (Kali Gandaki valley, Central Nepal), active from ~ 41 to 30 Ma (U-Th-Pb on monazite) points out to a more complex deformation pattern in the GHS characterized by in sequence shearing. The actual proposed models of exhumation of the GHS, based exclusively on the MCT and STD activities, are not able to explain the occurrence of the HHD and other in-sequence shear zones. Any model of the tectonic and metamorphic evolution of the GHS should account for the occurrence of the tectonic and metamorphic discontinuities within the GHS and its consequences on the metamorphic paths and on the assembly of Himalayan belt. References Godin L., Grujic D., Law, R. D. & Searle, M. P. 2006

Geochronologic constraints of the uplift and metamorphism along the Alpine Fault, South Island, New Zealand

International Nuclear Information System (INIS)

Chamberlain, C.P.; Zeitler, P.K.; Cooper, A.F.

1995-01-01

Geochronological studies of pegmatites and Alpine Schist exposed east of the Alpine Fault, South Island, New Zealand, reveal a complex history beginning with magmatism and metamorphism at c. 68 m.y. ago and ending with rapid uplift and exhumation in the last 5 m.y. Pegmatites exposed in the Mataketake Range give conventional U-Pb monazite and SHRIMP ion-probe zircon ages of 68 ± 2.6 Ma and 67.9 ± 2.5 Ma, respectively. Inasmuch as petrologic and isotopic data indicate that the Alpine pegmatites are melts derived from the Alpine Schist, the age of the pegmatites suggests that, at least locally, the high-grade metamorphism is considerably younger than previously assumed. We tentatively suggest that metamorphism, in at least some areas of the Alpine Schist, may be associated with Late Cretaceous transtension rather than resulting from the consequences of collision during the Rangitata Orogeny. 40 Ar/ 39 Ar studies of hornblendes from the Alpine Schist, collected from the Haast River to the Franz Josef Glacier area, reveal highly disturbed spectra. Despite this complexity, these analyses define a systematic decrease in ages both across-strike toward the Alpine Fault (Haast River traverse) and northwards along-strike towards Mt Cook. This pattern of decreasing 40 Ar/ 39 Ar hornblende ages is also observed in lower closure temperature systems such as zircon and apatite fission-track ages. We interpret the decrease in ages toward the fault to be the result of deeper exhumation in the immediate vicinity of the Alpine Fault, whereas we interpret the northward younging of fault-proximal samples to be a result of both more recent and possibly more extensive exhumation than occurred in areas to the south. (author). 55 refs., 4 figs., 2 tabs

State of the art of municipal solid wastes and hazard wastes disposal in Argentina; Diagnostico de la situacion del manejo de los residuos solidos municipales y peligrosos en Argentina

Energy Technology Data Exchange (ETDEWEB)

Savino, A.A.

1997-12-31

The author analyzes the up to date situation of Argentina related to Municipal solid Waste management after the political and economic challenges suffered by Argentina. The author concludes that this country needs more waste treatment plants and more investments for environmental management. (Author) 15 refs.

Late Cretaceous extension and exhumation of the Stong and Taku magmatic and metamorphic complexes, NE Peninsular Malaysia

NARCIS (Netherlands)

François, T.; Md Ali, M.A.; Matenco, L.; Willingshofer, E.; Ng, T.F.; Taib, N.I.; Shuib, M.K.

2017-01-01

Fragmentation of large continental areas by post-orogenic extension requires favourable geodynamic conditions and frequently occurs along pre-existing suture zones or nappe contacts, as exemplified by the Stong and Taku magmatic and metamorphic complexes of northern Peninsular Malaysia. For this

The metamorphic basement of the Cordillera Frontal of Mendoza: New geochronologic and isotopic data

International Nuclear Information System (INIS)

Basei, Miguel; Ramos, Victor A.; Vujovich, Graciela I.; Poma, Stella

1998-01-01

The metamorphic rocks of the Cordillera Frontal exposed in the Cordon del Portillo, Mendoza were examined by Rb/Sr geochronology and Nd/Sm isotopic analysis. The Rb/Sr data defined a Devonian age for the last metamorphic episode, similar to the previous K/Ar and Ar/Ar ages obtained in this region and western Precordillera. The isotopic analysis identified three sets of model ages: 1.- The oldest corresponds to a set of meta sedimentary rocks with a model age of 1,400 to 1,700 Ma; 2.- A monzogranodiorite with a model age of 1,000 Ma; and 3.- Metabasites with model ages between 577 and 330 Ma. These rocks are interpreted as 1.- A typical Grenvillian derived basement; 2.- Late Paleozoic granitoids derived from a different Proterozoic basement; and 3.- Some Eopaleozoic metabasites tectonically inter fingered with the Grenvillian basement. These new data are coherent with the existence of a Laurentia derived terrane, Chilenia, that was separated by oceanic rocks from the basement of Pre cordillera during Eopaleozoic times. This last basement known as the Cuyania terrane, was also derived from Laurentia. (author)

Forensic population data for 20 STR loci in Argentina

OpenAIRE

Borosky, Alicia; Toscanini, Ulises; Gómez, Andrea; Parolin, María Laura; Basso, Nestor Guillermo; Vullo, Carlos

2017-01-01

In order to provide useful information of forensic interest for the new markers included in the PowerPlex1 21 System (Promega Corp, USA), namely D1S1656, D6S1043 and D12S391, a population study was conducted in a sample of 907 unrelated healthy individuals from Argentina. Samples were randomly chosen from routine paternity testing. Blood samples or buccal swabs were collected after informed consent, taken from individuals of different urban populations from 7 provinces of Argentina: 464 indiv...

A new genus of Platynini (Coleoptera: Carabidae) from Argentina

OpenAIRE

ROIG-JUÑENT, Sergio

2003-01-01

Los Platynini constituyen un grupo de carábidos distribuidos ampliamente en América del Sur, existiendo la mayor diversidad de especies en las regiones tropicales de altura de Los Andes. En la Argentina y Chile, la mayoría de las especies de Platynini se hallan distribuidas en áreas extracordilleranas, conociéndose pocos datos para la región Andina. A partir de recolecciones realizadas en la Precordillera y Cordillera de los Andes en Mendoza (Argentina), se hallaron ejemplares pertenecientes ...

At what conditions does zircon grow/dissolve during high-T metamorphism? Relating zircon textures to PT-conditions

Science.gov (United States)

Kunz, Barbara E.; Regis, Daniele; Manzotti, Paola; Engi, Martin

2015-04-01

A key question in ziconology is when and how zircon grows during metamorphism. To shed light on zircon forming processes and the corresponding PT-conditions during high-T metamorphism a case study was undertaken. The Ivrea Zone (N-Italy) exposes a lower continental crustal section in which a continuous metamorphic field gradient from amphibolite to granulite facies is documented. This field gradient is thought to reflect protracted heating during late Paleozoic times, with a probable high-T peak in the Permian. We present first results from a primarily textural study supported by U-Pb ages, Th/U ratios and Ti-in-Zrn thermometry. Four types of zircon were identified based on their overgrowth proportions and the preservation of detrital cores. Zircon grains were thus classified as Type1 - detrital grains with no overgrowth or very narrow rims (300 Ma) and appears to reflect an early dehydration phase. Rim2b has Permian ages (median 275 Ma), is by far the most common overgrowth type, found in a wide PT-range. Its development appears related to biotite breakdown. Rim3 is texturally indicative of magmatic zircon, occurs only in diatexites. Rim4 is the latest overgrowth and is locally found at all metamorphic grades. Textural features suggest late fluid-related recrystallization of existing zircon. At lowest grade (675±35°C, 6±2 kbar) zircons show type1 only, overgrowths are too thin to clearly identify the rim type. Further upgrade (~700°C, 7 kbar) type1 and type2 dominate. Type2 zircons show rim1, rim2a and occasionally rim4. At the Mu-out isograd (750±50°C, 8.2±1.4 kbar) most zircons are of type2, now with rim2b instead of 2a, in addition to rim1 and rim4. Near and in granulite facies (to 800°C, 8±2 kbar) mostly zircon type2 and type4 are present. While rim1 gets more narrow with increasing metamorphic grade, rim2b grows significantly thicker. Occasionally rim2a and rim4 occur. Close to the Bt-out isograd (~860°C, 9.2±1.7 kbar), mostly type3 and type4 are

Tribulations and achievements: the early history of Olympism in Argentina.

Science.gov (United States)

Torres, C R

2001-01-01

By the end of the nineteenth century, modern sport had enchanted the people of Argentina. At that time the nation enjoyed a remarkable degree of economic prosperity and embarked on increasing political democratization. These circumstances, along with the fact that the nation was represented from the beginning, in 1894, on the International Olympic Committee seemed to favour Argentina as the spearhead of the diffusion of Olympism throughout South America. However, the country only enjoyed its first official Olympic participation in the Paris Games of 1924 - a few months after the establishment of the Argentine Olympic Committee. This essay explores the reception and diffusion of Olympism in Argentina. It reveals a process of gradual adoption including conflicting views on the relationship between the state and sport, several attempts at institutionalization, international misunderstandings and the role of politics and class.

Pressure-temperature evolution of eclogites from the Kechros complex in the Eastern Rhodope (NE Greece)

Science.gov (United States)

Mposkos, E.; Baziotis, I.; Proyer, A.

2012-06-01

The Rhodope Domain in NE Greece consists of different tectonometamorphic complexes involved in the Alpine collisional history between the Eurasian and African plates. In the Kechros Complex, which is the lowermost tectonic unit in the East Rhodope, a lense of kyanite eclogite occurs within orthogneiss and common eclogites are found between serpentinized peridotite and underlying pelitic gneisses. In kyanite eclogite, the high-pressure (HP) mineral assemblage is Grt + Omp (Jd35-55) + Ky + Ph + Qz + Rt + (indirectly inferred Tlc + Law); a Na-rich tremolite and zoisite formed at or near peak metamorphic conditions. In common eclogites, the HP mineral assemblage is Grt + Omp (Jd29-41) + Rt and, with less certainty, Amp (Gln-rich + Brs + Wnc + Hbl) ± Czo. The inclusions in garnet are glaucophane, actinolite, barroisite, hornblende, omphacite, clinozoisite, titanite, rutile and rarely paragonite and albite. In kyanite eclogite, peak P- T conditions are constrained at 2.2 GPa and 615°C using garnet-omphacite-phengite geothermobarometry and very similar values of 585 ± 32°C and 2.17 ± 0.11 GPa with the average P- T method, by which conditions of formation could also be narrowed down for the common eclogite (619 ± 53°C and 1.69 ± 0.17 GPa) and for a retrogressed eclogite (534 ± 36°C and 0.77 ± 0.11 GPa). Ages for the HP metamorphism in the Kechros Complex are not yet available. A Rb-Sr white mica age of 37 Ma from orthogneiss records a stage of the exhumation. The HP event may be coeval with the Eocene HP metamorphism (49-55 Ma) recorded in the Nestos Shear Zone in Central Rhodope and in the Attic-Cycladic crystalline belt, where it is interpreted as the result of subduction and final closure of the Axios/Vardar ocean and subsequent subduction of the Apulian continental crust (a promontory of the Africa continent) under the southern margin of the European continent in the late Cretaceous and early Tertiary.

Investigating the response of biotite to impact metamorphism: Examples from the Steen River impact structure, Canada

Science.gov (United States)

Walton, E. L.; Sharp, T. G.; Hu, J.; Tschauner, O.

2018-01-01

Impact metamorphic effects from quartz and feldspar and to a lesser extent olivine and pyroxene have been studied in detail. Comparatively, studies documenting shock effects in other minerals, such as double chain inosilicates, phyllosilicates, carbonates, and sulfates, are lacking. In this study, we investigate impact metamorphism recorded in crystalline basement rocks from the Steen River impact structure (SRIS), a 25 km diameter complex crater in NW Alberta, Canada. An array of advanced analytical techniques was used to characterize the breakdown of biotite in two distinct settings: along the margins of localized regions of shock melting and within granitic target rocks entrained as clasts in a breccia. In response to elevated temperature gradients along shock vein margins, biotite transformed at high pressure to an almandine-Ca/Fe majorite-rich garnet with a density of 4.2 g cm-3. The shock-produced garnets are poikilitic, with oxide and silicate glass inclusions. Areas interstitial to garnets are vesiculated, in support of models for the formation of shock veins via oscillatory slip, with deformation continuing during pressure release. Biotite within granitic clasts entrained within the hot breccia matrix thermally decomposed at ambient pressure to produce a fine-grained mineral assemblage of orthopyroxene + sanidine + titanomagnetite. These minerals are aligned to the (001) cleavage plane of the original crystal. In this and previous work, the transformation of an inosilicate (pargasite) and a phyllosilicate (biotite) to form garnet, an easily identifiable, robust mineral, has been documented. We contend that in deeply eroded astroblemes, high-pressure minerals that form within or in the environs of shock veins may serve as one of the possibly few surviving indicators of impact metamorphism.

Nanodiamond Formation at the Lithogenesis and Low-Stages of Regional Metamorphism

Science.gov (United States)

Simakov, S. K.; Melnik, N. N.; Vyalov, V. I.

2018-02-01

Samples of gilsonite from Adzharia, anthraxolite and graphite of coal from Taimyr, shungite from Karelia, and anthracite from Donbass are studied using Raman spectroscopy. Peaks at 1600 cm-1, indicating the presence of nanographite, are recorded in all samples. The anthracite sample from Donbass, 1330 cm-1, corresponds to the sp 3-line of carbon hybridization conforming to a nanodiamond. It is concluded that in nature diamonds can be formed at late stages of lithogenesis (catagensis, metagenesis), and for coals, it can occur at the zeolite stage of regional metamorphism of rocks, before the green schist stage.

Increasing Capacity for Environmental Engineering in Salta, Argentina

Science.gov (United States)

Rajal, Verónica B.; Cid, Alicia G.; Cruz, Mercedes C.; Poma, Hugo R.; Cacciabue, Dolores Gutierrez; Romano, Neli; Moraga, Norma B.; Last, Jerold A.

2012-01-01

Background The Fogarty International Center (FIC) of the United States National Institutes of Health includes the International Training and Research in Environmental and Occupational Health (ITREOH) Program. The “International Training Program in Environmental Toxicology and Public Health” Center, funded in 2002 is based at the University of California, Davis, and is part of the ITREOH group of Centers. It has major efforts focused at the public universities in Montevideo, Uruguay, and Salta, Argentina. Results Training and research efforts in Salta begun in 2005 in the College of Engineering. A donated used real-time PCR machine was the starting point and the initial FIC support was instrumental to face other problems including physical space, research projects and grants, trainees, training, networking, and distractions/opportunities in order to develop local capacities in Environmental Engineering using modern methodology. After six years of successful work, the Salta center has become a reference Center in the field, and is still growing and consolidating. Conclusions This program has had a significant impact locally and regionally. The model used in Argentina could be easily adapted to other fields or types of projects in Argentina and in other developing countries. PMID:22467330

Increasing capacity for environmental engineering in Salta, Argentina.

Science.gov (United States)

Rajal, Verónica B; Cid, Alicia G; Cruz, Mercedes C; Poma, Hugo R; Cacciabue, Dolores Gutierrez; Romano, Neli; Moraga, Norma B; Last, Jerold A

2013-01-01

The Fogarty International Center (FIC) of the United States National Institutes of Health includes the International Training and Research in Environmental and Occupational Health (ITREOH) Program. The "International Training Program in Environmental Toxicology and Public Health" Center, funded in 2002 is based at the University of California, Davis, and is part of the ITREOH group of Centers. It has major efforts focused at the public universities in Montevideo, Uruguay, and Salta, Argentina. Training and research efforts in Salta begun in 2005 in the College of Engineering. A donated used real-time PCR machine was the starting point and the initial FIC support was instrumental to face other problems including physical space, research projects and grants, trainees, training, networking, and distractions/opportunities in order to develop local capacities in Environmental Engineering using modern methodology. After 6 years of successful work, the Salta center has become a reference Center in the field, and is still growing and consolidating. This program has had a significant impact locally and regionally. The model used in Argentina could be easily adapted to other fields or types of projects in Argentina and in other developing countries. Copyright © 2012 Wiley Periodicals, Inc.

Greenstone: uso actual en Argentina

Directory of Open Access Journals (Sweden)

Marcela Fushimi

2018-04-01

Full Text Available Este trabajo presenta las características e historia del software para crear y gestionar bibliotecas digitales Greenstone, desarrollado inicialmente por la Universidad de Waikato, Nueva Zelandia en 1997. En primer lugar, se describe la comunidad de usuarios a nivel global, focalizando en el uso actual que el software ha alcanzado en Argentina: la cantidad de implementaciones disponibles, su evolución, el tipo, tamaño y variedad de los desarrollos existentes, así como su aplicación a la gestión de repositorios digitales de ciencia y tecnología en el ámbito de las instituciones científicas, tecnológicas y de educación superior en Argentina. En segundo lugar, se detallan las acciones llevadas a cabo a partir de la creación del Centro Nacional de Promoción de Greenstone en Argentina en 2009. Datos recabados en encuestas realizadas permitieron observar que las razones predominantes para elegir esta plataforma fueron, entre otras, su facilidad de instalación y configuración, su bajo nivel de requerimiento tecnológico, la generalizada escasez de recursos humanos dedicados a esta actividad, y la complejidad que presentaban los softwares alternativos existentes en ese momento. A lo largo de estos 8 años, tanto los repositorios digitales como los sistemas que los soportan evolucionaron drásticamente, modificando el escenario actual. Paralelamente, en 2016 la nueva versión mayor de Greenstone implementó una reingeniería completa del software para su adaptación a las tecnologías en uso: XML, XSLT, Web-services y Java. Como consecuencia de esto, la comunidad de desarrollo local se plantea nuevos desafíos para la migración de las bibliotecas digitales y repositorios implementados con versiones anteriores.

Visitantes florales diurnos del girasol (Helianthus annuus, Asterales: Asteraceae en la Argentina Diurnal floral visitors of sunflower (Helianthus annuus, Asterales: Asteraceae in Argentina

Directory of Open Access Journals (Sweden)

Juan P. Torretta

2010-06-01

Full Text Available El girasol (Helianthus annuus L. es un importante cultivo oleaginoso en la Argentina. Durante tres campañas agrícolas, se determinaron la diversidad y la abundancia del elenco de los visitantes florales diurnos de capítulos de girasol, en ocho sitios que cubren gran parte del área cultivada en Argentina. Setenta y seis morfo-especies de visitantes florales, pertenecientes a ocho órdenes, fueron capturados sobre capítulos de este cultivo. El principal orden fue Hymenoptera, con 37 especies o morfoespecies, de las cuales 32 fueron abejas (Apoidea. Las familias de abejas más representadas fueron Apidae (13, Megachilidae (11 y Halictidae (7. La abeja doméstica (Apis mellifera L. realizó el 93% de las visitas. La composición del elenco de visitantes no mostró un patrón de variación identificable a lo largo del día, ni con respecto a la distancia al borde del cultivo, pero varió entre sitios de muestreo. Se concluye que la abeja doméstica es el principal polinizador del girasol en la Argentina, aunque varias especies nativas de abejas (Melissodes tintinnans (Holmberg, M. rufithorax Brèthes, Melissoptila tandilensis Holmberg, y Megachile spp. podrían ser consideradas como potenciales polinizadores del cultivo.Sunflower (Helianthus annuus L. is an important oilseed crop in Argentina. During three agricultural years, the diversity and abundance of diurnal floral visitors of sunflower heads were determined in eight sites spanning much of this crop's cultivation area in Argentina. Seventysix morpho-species of floral visitors, belonging to eight orders, were captured on sunflower. The principal order was Hymenoptera, with 37 species or morpho-species, of which 32 were bees (Apoidea. The most represented bee families were Apidae (13, Megachilidae (11 and Halictidae (7. The domestic bee (Apis mellifera L. accounted for 93% of the visits. Floral visitor composition did not show an identifiable variation pattern either throughout the day or

Cooperation on Water management issues, Argentina : Project in the framework of Bilateral Cooperation between Argentina and the Netherlands : Case studies on water management issues in Argentina

NARCIS (Netherlands)

Querner, E.P.; Morabito, J.A.; Rebori, G.

2007-01-01

In Argentina parts of the country have problems encountered from too much water or suffer serious water shortages. The Humid Pampas encounter an increased rainfall since the 1970’s. In Mendoza Province water resources are limited and all the water from the rivers is used for agriculture, drinking

Migmatization and low-pressure overprinting metamorphism as record of two pre-Cretaceous tectonic episodes in the Santander Massif of the Andean basement in northern Colombia (NW South America)

Science.gov (United States)

Zuluaga, C. A.; Amaya, S.; Urueña, C.; Bernet, M.

2017-03-01

The core of the Santander Massif in the northern Andes of Colombia is dominated by migmatitic gneisses with a 7.5 kbar. Lithologies are overprinted by low-pressure metamorphism, related to extensive Jurassic intrusions and linked with growth of cordierite and equilibration of low-pressure mineral assemblages, recorded metamorphic conditions are Pangaea.

Redefining the public sphere: self-managed schools in Argentina

OpenAIRE

Feldfeber, Myriam

2003-01-01

El Proyecto de las Escuelas Experimentales o Autogestionadas de la Provincia de San Luis adquiere sentido en el marco de la denominada Transformación Educativa y de las políticas desarrolladas en las últimas décadas en Argentina, que, al igual que en gran parte de los países latinoamericanos, han estado orientadas por discursos y prácticas tendientes a legitimar un nuevo modelo económico, social, político, cultural y educativo. La reforma educativa argentina de la década del '90 puede analiza...

First record of Vespula vulgaris (Hymenoptera: Vespidae) in Argentina

OpenAIRE

Masciocchi, Maité; Beggs, Jacqueline R.; Carpenter, James M.; Corley, Juan Carlos

2016-01-01

Vespula vulgaris (Linnaeus) es un véspido social nativo de la región Holártica. En este trabajo reportamos la primera detección de esta especie en Argentina. Obreras de esta avispa fueron capturadas cerca de la ciudad de San Carlos de Bariloche (Argentina) en Febrero de 2010, mientras se tomaban muestras de otra avispa invasora, Vespula germanica (Fabricius) o chaqueta amarilla, de morfología externa y hábitos similares a la anteriormente mencionada. Además, detallamos algunos caracteres de i...

Cultivos transgénicos en Argentina : mitos y realidades

OpenAIRE

Cantamutto, Miguel; Poverene, Mónica

2003-01-01

Cantamutto, M., Poverene, M. (2003). Cultivos transgénicos en Argentina: mitos y realidades. Redes, 10(20), 171-181. La producción creciente de cultivos transgénicos en la Argentina es observada con preocupación por la población debido a que aparecen cada vez más voces planteando dudas y amenazas acerca de las consecuencias del uso de esta tecnología, que incluso se atribuye a oscuras manipulaciones políticas. ¿Tienen fundamento esos conceptos? ¿A qué aspectos del uso de organismos genétic...

Identidad y distribución geográfica de Stemodia durantifolia (Plantaginaceae en la Argentina

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María de las Mercedes Sosa

2012-12-01

Full Text Available Stemodia durantifolia es una especie con dos variedades que crece desde California hasta Chile. La variedad típica se ha citado en trabajos previos para la Argentina y la otra variedad, chilensis fue mencionada hasta el momento para Chile. En este trabajo se descarta la presencia de la variedad típica en el país, se da a conocer su área de distribución y se cita por primera vez a la variedad chilensis para la Argentina. Se describen e ilustran las dos variedades, se incluye un mapa de distribución y una clave para separarla de las restantes especies que crecen en Argentina.Identity and geographical distribution of Stemodia durantifolia (Plantaginaceae in Argentina. The typical variety has been cited in previous studies for Argentina, and the other variety, chilensis, was mentioned so far in Chile. This work rules out the typical variety in the country, describes its geographical distribution and cites for the first time the var. chilensis for Argentina. A description, illustration and a map of distribution of the species with these two varieties are provided, as well as a key to distinguish the other Argentinean species.

Petrological and zircon evidence for the Early Cretaceous granulite-facies metamorphism in the Dabie orogen, China

Science.gov (United States)

Gao, Xiao-Ying; Zhang, Qiang-Qiang; Zheng, Yong-Fei; Chen, Yi-Xiang

2017-07-01

An integrated study of petrology, mineralogy, geochemistry, and geochronology was carried out for contemporaneous mafic granulite and diorite from the Dabie orogen. The results provide evidence for granulite-facies reworking of the ultrahigh-pressure (UHP) metamorphic rock in the collisional orogen. Most zircons from the granulite are new growth, and their U-Pb ages are clearly categorized into two groups at 122-127 Ma and 188 ± 2 Ma. Although these two groups of zircons show similarly steep HREE patterns and variably negative Eu anomalies, the younger group has much higher U, Th and REE contents and Th/U ratios, much lower εHf(t) values than the older group. This suggests their growth is associated with different types of dehydration reactions. The older zircon domains contain mineral inclusions of garnet + clinopyroxene ± quartz, indicating their growth through metamorphic reactions at high pressures. In contrast, the young zircon domains only contain a few quartz inclusions and the garnet-clinopyroxene-plagioclase-quartz barometry yields pressures of 4.9 to 12.5 kb. In addition, the clinopyroxene-garnet Fe-Mg exchange thermometry gives temperatures of 738-951 °C. Therefore, the young zircon domains would have grown through peritectic reaction at low to medium pressures. The younger granulite-facies metamorphic age is in agreement not only with the adjacent diorite at 125 ± 1 Ma in this study but also the voluminous emplacement of coeval mafic and felsic magmas in the Dabie orogen. Mineral separates from both mafic granulite and its adjacent diorite show uniformly lower δ18O values than normal mantle, similar to those for UHP eclogite-facies metaigneous rocks in the Dabie orogen. In combination with major-trace elements and zircon Lu-Hf isotope compositions, it is inferred that the protolith of mafic granulites shares with the source rock of diorites, both being a kind of mafic metasomatites at the slab-mantle interface in the continental subduction channel

Using a Differential Scanning Calorimeter to Teach Phase Equilibria to Students of Igneous and Metamorphic Petrology

Science.gov (United States)

Maria, Anton H.; Millam, Evan L.; Wright, Carrie L.

2011-01-01

As an aid for teaching phase equilibria to undergraduate students of igneous and metamorphic petrology, we have designed a laboratory exercise that allows them to create a phase diagram from data produced by differential scanning calorimetry. By preparing and analyzing samples of naphthalene and phenanthrene, students acquire hands-on insight into…

The multiple applications of the nuclear techniques in Argentina; Las multiples aplicaciones de la tecnologia nuclear en Argentina

Energy Technology Data Exchange (ETDEWEB)

Manzini, Alberto C [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Programa de Radioisotopos y Aplicaciones

2001-07-01

A review is given of the use of nuclear technology in Argentina, especially in the field of the production of radioisotopes and radiopharmaceuticals, nuclear medicine, and industrial applications. The applications of ionizing radiation are also reviewed.

Chemical and oxygen isotopic properties of ordinary chondrites (H5, L6) from Oman: Signs of isotopic equilibrium during thermal metamorphism

Science.gov (United States)

Ali, Arshad; Nasir, Sobhi J.; Jabeen, Iffat; Al Rawas, Ahmed; Banerjee, Neil R.; Osinski, Gordon R.

2017-10-01

Mean bulk chemical data of recently found H5 and L6 ordinary chondrites from the deserts of Oman generally reflect isochemical features which are consistent with the progressive thermal metamorphism of a common, unequilibrated starting material. Relative differences in abundances range from 0.5-10% in REE (Eu = 14%), 6-13% in siderophile elements (Co = 48%), and >10% in lithophile elements (exceptions are Ba, Sr, Zr, Hf, U = >30%) between H5 and L6 groups. These differences may have accounted for variable temperature conditions during metamorphism on their parent bodies. The CI/Mg-normalized mean abundances of refractory lithophile elements (Al, Ca, Sm, Yb, Lu, V) show no resolvable differences between H5 and L6 suggesting that both groups have experienced the same fractionation. The REE diagram shows subtle enrichment in LREE with a flat HREE pattern. Furthermore, overall mean REE abundances are 0.6 × CI with enriched La abundance ( 0.9 × CI) in both groups. Precise oxygen isotope compositions demonstrate the attainment of isotopic equilibrium by progressive thermal metamorphism following a mass-dependent isotope fractionation trend. Both groups show a slope-1/2 line on a three-isotope plot with subtle negative deviation in Δ17O associated with δ18O enrichment relative to δ17O. These deviations are interpreted as the result of liberation of water from phyllosilicates and evaporation of a fraction of the water during thermal metamorphism. The resultant isotope fractionations caused by the water loss are analogous to those occurring between silicate melt and gas phase during CAI and chondrule formation in chondrites and are controlled by cooling rates and exchange efficiency.

Acute intermittent porphyria in Argentina: an update.

Science.gov (United States)

Cerbino, Gabriela Nora; Gerez, Esther Noemí; Varela, Laura Sabina; Melito, Viviana Alicia; Parera, Victoria Estela; Batlle, Alcira; Rossetti, María Victoria

2015-01-01

Porphyrias are a group of metabolic diseases that arise from deficiencies in the heme biosynthetic pathway. A partial deficiency in hydroxymethylbilane synthase (HMBS) produces a hepatic disorder named Acute Intermittent Porphyria (AIP); the acute porphyria is more frequent in Argentina. In this paper we review the results obtained for 101 Argentinean AIP families and 6 AIP families from foreign neighbour countries studied at molecular level at Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP). Thirty-five different mutations were found, of which 14 were described for the first time in our population. The most prevalent type of mutations was the missense mutations (43%) followed by splice defects (26%) and small deletions (20%). An odd case of a double heterozygous presentation of AIP in a foreign family from Paraguay is discussed. Moreover, it can be noted that 38 new families were found carrying the most frequent mutation in Argentina (p.G111R), increasing to 55.66% the prevalence of this genetic change in our population and adding further support to our previous hypothesis of a founder effect for this mutation in Argentina. Identification of patients with an overt AIP is important because treatment depends on an accurate diagnosis, but more critical is the identification of asymptomatic relatives to avoid acute attacks which may progress to death.

Population structure in Argentina.

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Marina Muzzio

Full Text Available We analyzed 391 samples from 12 Argentinian populations from the Center-West, East and North-West regions with the Illumina Human Exome Beadchip v1.0 (HumanExome-12v1-A. We did Principal Components analysis to infer patterns of populational divergence and migrations. We identified proportions and patterns of European, African and Native American ancestry and found a correlation between distance to Buenos Aires and proportion of Native American ancestry, where the highest proportion corresponds to the Northernmost populations, which is also the furthest from the Argentinian capital. Most of the European sources are from a South European origin, matching historical records, and we see two different Native American components, one that spreads all over Argentina and another specifically Andean. The highest percentages of African ancestry were in the Center West of Argentina, where the old trade routes took the slaves from Buenos Aires to Chile and Peru. Subcontinentaly, sources of this African component are represented by both West Africa and groups influenced by the Bantu expansion, the second slightly higher than the first, unlike North America and the Caribbean, where the main source is West Africa. This is reasonable, considering that a large proportion of the ships arriving at the Southern Hemisphere came from Mozambique, Loango and Angola.

Case study - Argentina

International Nuclear Information System (INIS)

Diaz, E.

1986-01-01

Antecedents and experience of nuclear activities in Argentina; the Atomic Energy Commission (CNEA). First development and research activities. Research reactors and radioisotopes plants. Health physics and safety regulations. - Feasibility studies for the first nuclear power plant. Awarding the first plant CNA I (Atucha I). Relevant data related to the different project stages. Plant performance. - Feasibility study for the second nuclear power plant. Awarding the second plant CNE (Central Nuclear Embalse). Relevant data related to established targets. Differences compared with the first station targets. Local participation. Plant performance. (orig./GL)

The Marbat metamorphic core-complex (Southern Arabian Peninsula) : reassessment of the evolution of a Neoproterozoic island-arc from petrological, geochemical and U-Pb zircon data

OpenAIRE

Barbey, P.; Denele, Y.; Paquette, J. L.; Berger, J.; Ganne, Jérôme; Roques, D.

2018-01-01

The Marbat basement (Sultanate of Oman) belongs to the Neoproterozoic accretion domain of the Arabian-Nubian shield. We present new geochronological, petrological and geochemical data as an extension of our previous study (Denele et al., 2017) re-interpreting this basement as a metamorphic core complex (MCC). We showed that this MCC consists of a metamorphic unit (Juffa complex) separated by an extensional detachment from a plutonic unit (Sadh complex and Tonalite plutons). Geochemical data s...

Charnockites and UHT metamorphism in the Bakhuis Granulite Belt, western Suriname : Evidence for two separate UHT events

NARCIS (Netherlands)

Klaver, Martijn; de Roever, Emond W F; Nanne, Josefine A M; Mason, Paul R D; Davies, Gareth R.

The Bakhuis Granulite Belt in western Suriname is an ultrahigh-temperature (UHT) metamorphic terrain in the centre of the Paleoproterozoic (Transamazonian) Guiana Shield. Next to the UHT granulites, the belt contains a 30 by 30km body of orthopyroxene-bearing granitoids: the Kabalebo charnockites.

[The demographic and occupational characteristics of Italian migrants to Argentina, 1880-1930].

Science.gov (United States)

Cacopardo, M C; Moreno, J L

1984-09-01

"This essay studies...the demographic and socio-professional characteristics of the Italian emigrants in Argentina during the period 1880-1930. Besides a reconstruction of the demographic variables (age, sex, mortality, and fertility) in the historical series, the essay also depicts the professional profile of the Italians in Argentina...." (summary in ENG, FRE) excerpt

Psychotherapy in Argentina: a clinical case from an integrative perspective.

Science.gov (United States)

Gómez, Beatriz

2007-08-01

The article describes psychotherapy practice in Argentina. It outlines the main features of training and regulation of clinical psychologists. A brief description of the main treatment approaches and the major current challenges is presented. Subsequently it delineates the probable treatment locations and options for a 30-year-old woman, Mrs. A, seeking psychological help in Argentina. The case is then considered from an integrative perspective starting with the intake process, which includes a comprehensive pretreatment assessment followed by the treatment plan. Its course is described as composed of four stages: (1) psychoeducational initial intervention, (2) psychotherapy for symptom alleviation, (3) marital treatment, and (4) psychoeducational final intervention. Posttreatment evaluation and possible outcome and prognosis are presented, as well as factors that might prevent improvement. The article ends with a hopeful view of the future role of psychotherapy in Argentina. (c) 2007 Wiley Periodicals, Inc.

Peronism and the origin of workers in Argentina Peronismo e oriegem dos operários na Argentina

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Carlos R. Etulain

2007-05-01

Full Text Available This article analyses the way the workers and popular fronts inserted themselves in the Peronism when it appeared in the 40’s, in Argentina. Showing the adhesion of the different sectors of Argentinean workers, it presents the researchers opinion on the subject. The historical period focuses the first and the second period of Peron as president (1946-1955. Keywords: Peronism. Left. Workers. Unionism. Populism. New Workers. O trabalho analisa a forma como os trabalhadores e os setores populares se inseriram no peronismo uma vez do seu surgimento, nos anos 40, na Argentina. Apontando para a adesão dos diferentes setores de trabalhadores argentinos, o artigo apresenta as posições dos investigadores do assunto. O período histórico se centra na primeira e segunda presidência de Perón (1946-1955. Palavras-chave: Peronismo. Esquerda. Trabalhadores. Sindicalismo. Populismo. Trabalhadores Novos.

La Argentina y el Plan Marshall: promesas y realidades Argentina and the Marshall Plan: promises and realities

Directory of Open Access Journals (Sweden)

Mario Rapoport

2009-06-01

Full Text Available El artículo analiza los intereses y prioridades de la política económica externa de los Estados Unidos y las complejas relaciones entre Washington y el gobierno de Buenos Aires en relación a la puesta en marcha del Plan Marshall de reconstrucción de Europa Occidental. La no participación de la Argentina en él dificultó su proceso de industrialización al restringir su comercio con el viejo continente e impedirle obtener las divisas necesarias para comprar en los EEUU, proveedor fundamental de los bienes que necesitaba.The article analyze both the interests and priorities of the foreign economic policy of the United States and the complex relationship between Washington and the peronist government when President Truman impose the Marshall Plan in Europe making more difficult the industrialisation of Argentina.

Ricardo Dyrgalla (1910-1970), pioneer of rocket development in Argentina

Science.gov (United States)

de León, Pablo

2009-12-01

One of the most important developers of liquid propellant rocket engines in Argentina was Polish-born Ricardo Dyrgalla. Dyrgalla immigrated to Argentina from the United Kingdom in 1946, where he had been studying German weapons development at the end of the Second World War. A trained pilot and aeronautical engineer, he understood the intricacies of rocket propulsion and was eager to find practical applications to his recently gained knowledge. Dyrgalla arrived in Argentina during Juan Perón's first presidency, a time when technicians from all over Europe were being recruited to work in various projects for the recently created Argentine Air Force. Shortly after immigrating, Dyrgalla proposed to develop an advanced air-launched weapon, the Tábano, based on a rocket engine of his design, the AN-1. After a successful development program, the Tábano was tested between 1949 and 1951; however, the project was canceled by the government shortly after. Today, the AN-1 rocket engine is recognized as the first liquid propellant rocket to be developed in South America. Besides the AN-1, Dyrgalla also developed several other rockets systems in Argentina, including the PROSON, a solid-propellant rocket launcher developed by the Argentine Institute of Science and Technology for the Armed Forces (CITEFA). In the late 1960s, Dyrgalla and his family relocated to Brazil due mostly to the lack of continuation of rocket development in Argentina. There, he worked for the Institute of Aerospace Technology (ITA) until his untimely death in 1970. Ricardo Dyrgalla deserves to be recognized among the world's rocket pioneers and his contribution to the science and engineering of rocketry deserves a special place in the history of South America's rocketry and space flight advocacy programs.

Coleópteros acuáticos de lagunas situadas en el noroeste de la provincia de Corrientes, Argentina Aquatic Coleoptera from ponds in the northwest of Corrientes Province, Argentina

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María C. Gomez Lutz

2012-06-01

Full Text Available El objetivo de este estudio es contribuir al conocimiento de la biodiversidad de coleópteros acuáticos del NE argentino. Los sitios de muestreo corresponden a dos lagunas permanentes ubicadas en el departamento Capital de la provincia de Corrientes, Argentina. Los muestreos fueron realizados desde octubre de 2010 a marzo de 2011. En total, 107 especies de coleópteros, incluidas en 40 géneros y ocho familias fueron registradas: Haliplidae, Dytiscidae, Noteridae, Dryopidae, Hydrochidae, Hydrophilidae, Limnichidae y Scirtidae. La especie Berosus hamatus Knisch es un nuevo registro para la Argentina. Dos familias (Haliplidae y Dryopidae, cuatro géneros (Haliplus Latreille; Pelonomus Erichson, Onopelmus Spangler, Phaenonotum Sharp y 14 especies son citados por primera vez para la provincia de Corrientes.This study aims to improve the knowledge of aquatic Coleoptera biodiversity in northeastern Argentina. The sampling sites correspond to two permanent ponds located in the department Capital of Corrientes Province, Argentina. The samples were collected between October 2010 and March 2011. A total of 107 species of beetles, including 40 genera and 8 families were recorded: Haliplidae, Dytiscidae, Noteridae, Dryopidae, Hydrochidae, Hydrophilidae, Limnichidae and Scirtidae. Berosus hamatus Knisch is a new record for Argentina. Two families (Haliplidae and Dryopidae, four genera (Haliplus Latreille; Pelonomus Erichson, Onopelmus Spangler, Phaenonotum Sharp and 14 species are cited for the first time for Corrientes Province.

Las negociaciones para el acuerdo cinematográfico de 1948 entre Argentina y España (1939-1948 / The Film Agreement Negotiations: Argentina and Spain (1939-1948

Directory of Open Access Journals (Sweden)

Emeterio Díez Puertas

2016-08-01

Full Text Available La política expansionista del cine argentino y, desde 1942, razones de supervivencia ante el acoso de Hollywood empujan a la Asociación de Productores de Películas Argentinas (APPA a presionar al gobierno español para que firme un acuerdo cinematográfico. Este se rubrica en1948, tras casi diez años de tensas negociaciones. Pero los artículos del acuerdo, más que responder a los deseos de la APPA, reflejan los intereses y la hermandad alcanzada por el franquismo y el peronismo.Palabras clave: España, Argentina, comercio cinematográfico, Asociación de Productores de Películas Argentinas.AbstractThe expansionist policy of Argentine cinema and the power of Hollywood's entertainment industry since 1942, push the Argentinean Film Producers Association (APPA to put pressure on the Spanish government to sign a film agreement. This was signed in 1948, after almost ten years of tense negotiations. However, the articles of the agreement, rather than responding to the wishes of the APPA, reflect the treaty of friendship between the Franco regime and the Peronism.Keywords: Spain, Argentina, Movie Trade, Argentinean Film Producers Association.

La llegada de Gramsci a la Argentina: una relectura sobre Héctor P. Agosti-Gramsci’s Influence in Argentina: a New Reading of the Work of Héctor P. Agosti

Directory of Open Access Journals (Sweden)

Alexia Massholder

2011-12-01

Full Text Available With few exceptions, the impact of the work of Antonio Gramsci in Argentina is generally associated with the so called “Argentinian gramscians”, many of whom met around the journal Pasado y Presente, headed by José Aricó, without considering Gramsci’s earlier influence. However, it is often forgotten that the first introduction of Gramsci to Argentina was by the hand of Héctor P. Agosti. Agosti influenced many young intellectuals who subsequently congregated around Aricó. Beyond the observations made in this article regarding Agosti’s detractors, the aim here is to contribute to the diffusion, and presentation to the public of the thought of one of the most remarkable intellectuals that have arisen in the Communist Party of Argentina. This article also delves into relatively unexamined connections between the works of Agosti and Grasmci, highlighting the role played by the former in introducing the works of this Italian intellectual into Argentina during that period.

Tectono-metamorphic evolution of high-P/T and low-P/T metamorphic rocks in the Tia Complex, southern New England Fold Belt, eastern Australia: Insights from K-Ar chronology

Science.gov (United States)

Fukui, Shiro; Tsujimori, Tatsuki; Watanabe, Teruo; Itaya, Tetsumaru

2012-10-01

The Tia Complex in the southern New England Fold Belt is a poly-metamorphosed Late Paleozoic accretionary complex. It consists mainly of high-P/low-T type pumpellyite-actinolite facies (rare blueschist facies) schists, phyllite and serpentinite (T = 300 °C and P = 5 kbar), and low-P/high-T type amphibolite facies schist and gneiss (T = 600 °C and P Tia granodiorite). White mica and biotite K-Ar ages distinguish Carboniferous subduction zone metamorphism and Permian granitic intrusions, respectively. The systematic K-Ar age mapping along a N-S traverse of the Tia Complex exhibits a gradual change. The white mica ages become younger from the lowest-grade zone (339 Ma) to the highest-grade zone (259 Ma). In contrast, Si content of muscovite changes drastically only in the highest-grade zone. The regional changes of white mica K-Ar ages and chemical compositions of micas indicate argon depletion from precursor high-P/low-T type phengitic white mica during the thermal overprinting and recrystallization by granitoids intrusions. Our new K-Ar ages and available geological data postulate a model of the eastward rollback of a subduction zone in Early Permian. The eastward shift of a subduction zone system and subsequent magmatic activities of high-Mg andesite and adakite might explain formation of S-type granitoids (Hillgrove suite) and coeval low-P/high-T type metamorphism in the Tia Complex.

Miocene metamorphism of pan-African granites in the Edough Massif (NE Algeria)

International Nuclear Information System (INIS)

Hammor, D.; Lancelot, J.

1998-01-01

The Edough Massif is the eastern most crystalline core of the Maghrebides that represents the African segment of the west Mediterranean Alpine belt. U-Pb zircon dating provides upper intercept ages of 595± My and 606±55 My and orthogneiss of the lower unit and a deformed leucogranite of the upper pelitic unit, respectively. These ages suggest emplacement of the two granitoids during the Pan-African orogeny. Monazites from a paragneiss sample gave a 18± My U-Pb age that points to a Miocene age of the high-temperature metamorphism. (authors)

Research of the chemical activity of microgrinding coals of various metamorphism degree

Science.gov (United States)

Burdukov, A. P.; Butakov, E. B.; Kuznetsov, A. V.

2017-09-01

In this paper, we investigate the effect of mechanically activating grinding of coals of various degrees of metamorphism by two different methods - determination of the flash time in a vertical tubular furnace and thermogravimetric analysis. In the experiments, the coals that had been processed on a vibrating centrifugal mill and a disintegrator, aged for some time, were compared. The experiments showed a decrease in the ignition temperature of mechanically activated coals - deactivation of fuel, as well as the effect of mechanical activation on the further process of thermal-oxidative degradation.

Un género nuevo de Platynini (Coleoptera: Carabidae de la Argentina A new genus of Platynini (Coleoptera: Carabidae from Argentina

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Sergio ROIG-JUÑENT

2003-07-01

Full Text Available Los Platynini constituyen un grupo de carábidos distribuidos ampliamente en América del Sur, existiendo la mayor diversidad de especies en las regiones tropicales de altura de Los Andes. En la Argentina y Chile, la mayoría de las especies de Platynini se hallan distribuidas en áreas extracordilleranas, conociéndose pocos datos para la región Andina. A partir de recolecciones realizadas en la Precordillera y Cordillera de los Andes en Mendoza (Argentina, se hallaron ejemplares pertenecientes a dos especies de dicha tribu de carábidos. El estudio de este material ha permitido establecer dos nuevas especies cuyos caracteres justifican su agrupación en un nuevo género, Austroglyptolenus nov. gen. La presencia de una carena dorsal en la protibia y el poseer la base del lóbulo medio esclerotizado agruparían a Austroglyptolenus nov. gen. con los géneros Glyptolenus Bates y Glyptolenoides Perrault. De ellos se diferencia por la forma de los metatarsitos, ausencia de diente en el saco interno y la presencia de un anillo de espículas en la bursa copulatriz. Por ello las especies de Austroglyptolenus nov. gen., A. mendozensis sp. nov. y A. precordillerae sp. nov. están más relacionadas con las especies de América del Sur tropical que con los Platynini australes extramontanos de la Argentina y Chile. En este aporte se proveen las descripciones e ilustraciones del género y de las nuevas especies, así como también claves para identificar los nuevos taxones.Platynini is a widespread tribe of carabids in South America, having the largest diversity of species in the tropical highlands of Andes. In Argentina and Chile, most of the platinine species are distributed in extra-Andean regions. Several specimens of platynine have been found in samples from the Precordillera and the Andes in Mendoza (Argentina. The study of these materials revealed two new species, whose characters justify the creation of a new genus, Austroglyptolenus gen. nov. The

Felsic granulite with layers of eclogite facies rocks in the Bohemian Massif; did they share a common metamorphic history?

Science.gov (United States)

Jedlicka, Radim; Faryad, Shah Wali

2017-08-01

High pressure granulite and granulite gneiss from the Rychleby Mountains in the East Sudetes form an approximately 7 km long and 0.8 km wide body, which is enclosed by amphibolite facies orthogneiss with a steep foliation. Well preserved felsic granulite is located in the central part of the body, where several small bodies of mafic granulite are also present. In comparison to other high pressure granulites in the Bohemian Massif, which show strong mineral and textural re-equilibration under granulite facies conditions, the mafic granulite samples preserve eclogite facies minerals (garnet, omphacite, kyanite, rutile and phengite) and their field and textural relations indicate that both mafic and felsic granulites shared common metamorphic history during prograde eclogite facies and subsequent granulite facies events. Garnet from both granulite varieties shows prograde compositional zoning and contains inclusions of phengite. Yttrium and REEs in garnet show typical bell-shaped distributions with no annular peaks near the grain rims. Investigation of major and trace elements zoning, including REEs distribution in garnet, was combined with thermodynamic modelling to constrain the early eclogite facies metamorphism and to estimate pressure-temperature conditions of the subsequent granulite facies overprint. The first (U)HP metamorphism occurred along a low geothermal gradient in a subduction-related environment from its initial stage at 0.8 GPa/460 °C and reached pressures up to 2.5 GPa at 550 °C. The subsequent granulite facies overprint (1.6-1.8 GPa/800-880 °C) affected the rocks only partially; by replacement of omphacite into diopside + plagioclase symplectite and by compositional modification of garnet rims. The mineral textures and the preservation of the eclogite facies prograde compositional zoning in garnet cores confirm that the granulite facies overprint was either too short or too faint to cause recrystallisation and homogenisation of the eclogite

CROSSROADS BETWEEN EDUCATION POLICIES AND INDIGENOUS LANGUAGES MAINTENANCE IN ARGENTINA

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Ana Carolina Hecht

2010-06-01

Full Text Available Process of language shift is explained by many researchers since linguistic and anthropological perspectives. This area focuses on the correlations between social processes and changes in systems of use of a language. This article aims to address these issues. In particular, we analyze the links between educational-linguistic policy and the maintenance of the languages spoken in Argentina. In doing so, we explore this field taking into account the linguistic and educational policies implemented about indigenous languages in Argentina.

La crisis Argentina y los medios de comunicación

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Federico Rey Lennon

2015-01-01

Full Text Available La crisis económica en Argentina ha sido difícil: revueltas, saqueos, renuncias cacerolazos, angustias, escepticismo, corridas bancarias. Los medios de comunicación transformados en actores sociales desempeñando papeles claves de control político, en un medio de escepticismo e inutilidad de la clase dirigente Argentina y de los políticos. El artículo intenta explicar el papel que le cupo a los medios en la construcción de esta realidad.

Rocky Mountain spotted fever in Argentina.

Science.gov (United States)

Paddock, Christopher D; Fernandez, Susana; Echenique, Gustavo A; Sumner, John W; Reeves, Will K; Zaki, Sherif R; Remondegui, Carlos E

2008-04-01

We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain spotted fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal spotted fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of spotted fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for spotted fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high fever, severe headache, myalgias, and petechial rash. The diagnosis of spotted fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.

The Tribe Anisoscelini (Hemiptera: Heteroptera, Coreidae) in Argentina.

Science.gov (United States)

Coscarón, María Del Carmen; Pall, José Luis

2015-10-23

Eight genera and 21 species of the tribe Anisoscelini (Coreidae, Coreinae) are recorded in Argentina: Anisoscelis foliaceus (Fabricius); Coribergia declivicollis (Berg); Dalmatomammurius vandoesburgi (Brailovsky); Holymenia hystrio (Fabricius); Leptoglossus chilensis (Spinola); L. cinctus (Herrich-Schaeffer); L. concolor Walker; L. crassicornis (Dallas); L. dentatus Berg; L. fasciatus (Westwood); L. gonagra (Fabricius); L. impictus (Stål); L. ingens (Mayr); L. neovexillatus Allen; L. quadricollis (Westwood); L. stigma (Herbst); L. vexillatus (Stål); L. zonatus (Dallas); Phthia lunata (Fabricius); Phthiacnemia picta (Drury) and Ugnius kermesinus (Linnaeus). A key to genera belonging to the tribe is provided. L. stigma is recorded for the first time in Argentina with new locality records for La Rioja, Salta and San Juan.

Dictadura y relaciones internacionales: Argentina y Chile entre 1829 y 1852

OpenAIRE

Lacoste, Pablo

2001-01-01

The study analizes the relationaship between Argentina and Chile during Rosas’ dictatorship in Buenos Aires (1829-1852) in comparison with the previous period (1810-1829) and the later (1852-1881). Three parameters are considered: the treaties signature, the existence of diplomatic representations and the comercial policies. The study of the mentioned parameters showes the bilateral relationship deterioration during the dictatorship. The study analizes the relationaship between Argentina a...

Exhumation And Evolution Of Al-Taif Metamorphic Core Complex (Western Arabian Shield) During Dextral Transpressional Regime

Science.gov (United States)

El-Fakharani, Abdelhamid; El-Shafei, Mohamed; Hamimi, Zakaria

2013-04-01

Al-Taif metamorphic belt is a NE-trending belt decorating steeply dipping major transpressional shear zone in western central Arabian Shield. It comprises gneisses and migmatites that were syn-kinematically invaded under relatively high-grade metamorphic conditions by voluminous granitic bodies and a confluence of pegmatitic veins. Field mapping and outcrop investigation reveal that the belt was evolved during at least three Neoproterozoic deformations (D1-D3). D1 and D2 were progressive deformations, took place during a contractional regime, and resulted in SW-mildly plunging isoclinal folds, superimposed by NE- gently to moderately plunging folds. The prevailed tectonic regime during D3was primordially plastic, accompanied with a NE-oriented oblique shearing that was subsequently evolved as semi ductile-semi brittle shearing during an episode of exhumation. Mesoscopic kinematic indicators, as well as microstructural analysis of the collected rock samples, reflect dextral sense of shearing. Such style of shearing is most probably the conjugate trend of the NNW- to NW- oriented sinistral Najd Fault System. Various cross cutting structures and overprinting relations were detected at both the outcrop- and microscopic scales, including; ductile S2folia with ESE-plunging amphibole mineral lineations; narrow, steeply dipping ductile D2 shear zones; and semi brittle to brittle fault zones. S-C' fabrics, asymmetric strain shadows around porphyroclasts and drag fault indicate a top-to-the-NE sense of shear for most structures. The geometry and style of deformation, together with map pattern highlighted in this study attest a simple shear rotational strain origin for the domed mylonitic foliation (S1) and mineral elongation lineation (L1). This result is in congruent with the landform pattern recorded in the inner parts of the metamorphic core complexes.

Grain coarsening in polymineralic contact metamorphic carbonate rocks: The role of different physical interactions during coarsening

DEFF Research Database (Denmark)

Brodhag, Sabine; Herwegh, Marco; Berger, Alfons

2011-01-01

) and microstructures with considerable second-phase volume fractions of up to 0.5. The variations might be of general validity for any polymineralic rock, which undergoes grain coarsening during metamorphism. The new findings are important for a better understanding of the initiation of strain localization based...... on the activation of grain size dependent deformation mechanisms....

Argentina.

Science.gov (United States)

1993-02-01

Background notes on Argentina provide a profile of the geography, selected demographic features, government and economic conditions. Descriptive text includes a discussion of the people, their history and political conditions, the government and officials, the state of the economy, their defense, foreign relations, and relations with the US. The 1992 estimated population was about 33 million of whom 97% are European (mostly Spanish and Italian). Religions represented are Roman Catholic (92%), Protestant (2%), Jewish (2%), and other (4%). Adult literacy is 95%. 36% are engaged in industry and commerce, 20% in services, 19% in agriculture, 6% in transport and communications, and 19% other. Per capita gross domestic product was $4,500. There are only 50,000 native Indians remaining in peripheral provinces. The population enjoys a high standard of living and a low growth rate. The country was shaped by dominant forces: modern agricultural techniques and the integration of the country into the world economy. Foreign investment aided the economic revolution. Conservative and radical rule has swung the country back and forth politically since 1916. Colonel Juan Domingo Peron led a successful military coup in 1943 and was elected in 1946. Policies were instituted to give a greater voice to the working class, and with the influences of his wife, women's groups. In 1955, he was ousted by the military, which failed to revive the economy and quiet increasing terrorism. After a number of difficult elections, Peron was reinstated as president in 1973. Extremists on the left and right threatened public order; the military as a consequence imprisoned persons indefinitely. Peron's wife succeeded him after his death, but was removed from office in the military coup of 1976. Basic human rights were violated during this period. By 1983, a fair election was held and support increased for a democratic system. In 1989, Carlos Saul Menem, a Peronist candidate, won and established

Research reactors in Argentina

International Nuclear Information System (INIS)

Carlos Ruben Calabrese

1999-01-01

Argentine Nuclear Development started in early fifties. In 1957, it was decided to built the first a research reactor. RA-1 reactor (120 kw, today licensed to work at 40 kW) started operation in January 1958. Originally RA-1 was an Argonaut (American design) reactor. In early sixties, the RA-1 core was changed. Fuel rods (20% enrichment) was introduced instead the old Argonaut core design. For that reason, a critical facility named RA-0 was built. After that, the RA-3 project started, to build a multipurpose 5 MW nuclear reactor MTR pool type, to produce radioisotopes and research. For that reason and to define the characteristics of the RA-3 core, another critical facility was built, RA-2. Initially RA-3 was a 90 % enriched fuel reactor, and started operation in 1967. When Atucha I NPP project started, a German design Power Reactor, a small homogeneous reactor was donated by the German Government to Argentina (1969). This was RA-4 reactor (20% enrichment, 1W). In 1982, RA-6 pool reactor achieved criticality. This is a 500 kW reactor with 90% enriched MTR fuel elements. In 1990, RA-3 started to operate fueled by 20% enriched fuel. In 1997, the RA-8 (multipurpose critical facility located at Pilcaniyeu) started to operate. RA-3 reactor is the most important CNEA reactor for Argentine Research Reactors development. It is the first in a succession of Argentine MTR reactors built by CNEA (and INVAP SE ) in Argentina and other countries: RA-6 (500 kW, Bariloche-Argentina), RP-10 (10MW, Peru), NUR (500 kW, Algeria), MPR (22 MW, Egypt). The experience of Argentinian industry permits to compete with foreign developed countries as supplier of research reactors. Today, CNEA has six research reactors whose activities have a range from education and promotion of nuclear activity, to radioisotope production. For more than forty years, Argentine Research Reactors are working. The experience of Argentine is important, and argentine firms are able to compete in the design and

Payenia volcanic province, southern Mendoza, Argentina

DEFF Research Database (Denmark)

Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

2013-01-01

The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...

Argentina and Brazil's competition over Bolivian's resources, needs and means half a century later

International Nuclear Information System (INIS)

Behrens, A.

1988-01-01

For fifty years Bolivia has managed to achieve an unstable balance of power between its most powerful neighbours, while still keeping together an ethnically diverse and poorly integrated country. However, prospects are grim. Bolivia's most important trade able goods face receding markets and natural gas exports to Argentina are likely to dwindle as that country develops its own domestic fields. Brazil, could substitute for Argentina but it needs to overcome a bitter legacy of commercial frustration with Bolivia and the opposition of Brazil's national oil company to natural gas imports. Moreover, Argentina may soon be a net exporter of natural gas as well. However, neither Brazil nor Argentina, both of whom share a sizeable frontier with Bolivia should not want to see her under too much distress. Pooling the natural gas resources of Argentina and Bolivia could cater for more orderly and reliable regional trade than in the past. The combined resources could be managed by a private enterprise (Gas del Plata) with all three countries as major shareholders. Reliable natural gas supplies may even help Brazil to revert its autarchic developmental trends. (author)

Acerca De La Identidad Boliviana En Argentina. Un Análisis De Tres Casos De Estudio En La Provincia De Buenos Aires, Argentina

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Mercedes Mariano

2015-08-01

Full Text Available This paper is about the representations, practices and cultural expressions carried out by groups of Bolivian immigrants and their descendants in the cities of Olavarria, Tandil and Azul in the province of Buenos Aires, Argentina. For this purpose, the three case studies presented are analyzed based on the theoretical notions of identities and ethnic groups proper to the field of social anthropology. It thus seeks to contribute to knowledge about the construction of the identities of Bolivian immigrants in Argentina and, especially, to the discussion of those perspectives that propose the cultural assimilation of these groups into the host society.

Tobacco industry targeting youth in Argentina

Science.gov (United States)

Braun, S; Mejia, R; Ling, P M; Pérez-Stable, E J

2013-01-01

Background/aim Argentina has one of the highest cigarette smoking rates among both men and women in the Americas and no legislated restrictions on tobacco industry advertising. The tobacco industry has traditionally expanded markets by targeting adolescents and young adults. The objective of this study was to determine whether and how the tobacco industry promotes cigarettes to adolescents in Argentina. Methods We conducted a systematic search of tobacco industry documents available through the internet dated between 1995 and 2004 using standard search terms to identify marketing strategies in Argentina. A selected review of the four leading newspapers and nine magazines with reported high readership among adolescents was completed. The selected print media were searched for tobacco images and these were classified as advertisements if associated with a commercial product or as a story if not. Results The tobacco industry used market segmentation as a strategy to target Argentinean consumers. British American Tobacco (BAT) undertook a young adult psychographic study and classified them as “progressives”, “Jurassics” or “conservatives” and “crudos” or “spoiled brats”. BAT marketed Lucky Strike to the “progressives” using Hollywood movies as a vehicle. The tobacco industry also targeted their national brands to the conservatives and linked these brands with “nationalistic values” in advertising campaigns. Philip Morris promoted Marlboro by sponsoring activities directed at young people and they launched the 10 cigarettes packet as a starter vehicle. Conclusions The tobacco industry used psychographic segmentation of the population and developed advertising strategies focused on youth. Tobacco control researchers and advocates must be able to address these strategies in counter-marketing interventions. PMID:18299308

Genomics of a Metamorphic Timing QTL: met1 Maps to a Unique Genomic Position and Regulates Morph and Species-Specific Patterns of Brain Transcription

Science.gov (United States)

Page, Robert B.; Boley, Meredith A.; Kump, David K.; Voss, Stephen R.

2013-01-01

Very little is known about genetic factors that regulate life history transitions during ontogeny. Closely related tiger salamanders (Ambystoma species complex) show extreme variation in metamorphic timing, with some species foregoing metamorphosis altogether, an adaptive trait called paedomorphosis. Previous studies identified a major effect quantitative trait locus (met1) for metamorphic timing and expression of paedomorphosis in hybrid crosses between the biphasic Eastern tiger salamander (Ambystoma tigrinum tigrinum) and the paedomorphic Mexican axolotl (Ambystoma mexicanum). We used existing hybrid mapping panels and a newly created hybrid cross to map the met1 genomic region and determine the effect of met1 on larval growth, metamorphic timing, and gene expression in the brain. We show that met1 maps to the position of a urodele-specific chromosome rearrangement on linkage group 2 that uniquely brought functionally associated genes into linkage. Furthermore, we found that more than 200 genes were differentially expressed during larval development as a function of met1 genotype. This list of differentially expressed genes is enriched for proteins that function in the mitochondria, providing evidence of a link between met1, thyroid hormone signaling, and mitochondrial energetics associated with metamorphosis. Finally, we found that met1 significantly affected metamorphic timing in hybrids, but not early larval growth rate. Collectively, our results show that met1 regulates species and morph-specific patterns of brain transcription and life history variation. PMID:23946331

Two new species of Psectrascelis (Coleoptera: Tenebrionidae from western Argentina

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Gustavo E. FLORES

2007-01-01

Full Text Available Se describen dos nuevas especies del género Psectrascelis Solier (Pimeliinae: Nycteliini del oeste de Argentina, P. argentina sp. nov. a gran altitud en la Precordillera de San Juan y P. telteca sp. nov. en la llanura de Mendoza, y se las incluye en la clave mas reciente del género. Se proveen datos sobre la distribución y el hábitat, así como fotografías de los adultos y pronotos y dibujos de los genitalia masculinos.

Measured radon inside housings the Republic Argentina

International Nuclear Information System (INIS)

Canoba, A.; Arnaud, M.; Lopez, F.; Oliveira, A.A.

1998-01-01

They have been measured the radon concentration in houses in different city's in Argentina Republic. For they were used it as method mensuration detectors appearances nuclear detecting electrets and detectors based on the adsorption radon in activated carbon

Enhanced Contacts for Inverted Metamorphic Multi-Junction Solar Cells Using Carbon Nanotube Metal Matrix Composites

Science.gov (United States)

2018-01-18

substrates through a shadow mask. The native oxide was removed by HCl (hydrochloric acid) immersion immediately before the deposition process...34Pushing Inverted Metamorphic Multijunction Solar Cells Toward Higher Efficiency at Realistic Operating Conditions," IEEE Journal of Photovoltaics, vol. 3...Multijunction Solar Cells," IEEE Journal of Photovoltaics, vol. 2, pp. 377-381, Jul 2012. [7] F. Newman, et al., "PROGRESS IN ADAPTING INVERTED

Cultural Diversity: "Reports from Brazil and Argentina"

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Célia Regina Rossi

2007-06-01

Full Text Available This article tells two experiences of projects carried through in schools of basic education whose thematic it was the work with the cultural diversity, the valuation of other cultures and reflections on the proper culture The work was carried through in two schools: one in the state of São Paulo, the city of Rio Claro where as the thematic one worked was the Hip-Hop and cultural manifestations local Brazilians the second in the capital of a Argentina province, in the city of Paraná where it worked the contact and the relation enter the cultural manifestations of Brazil and Argentina The central objective of this work was to think ways that could lead to the construction of a school that it considered the differences and the learning that happens when these (the differences they are in relation.

Nuevos registros del género Cissampelos (Menispermaceae para la flora Argentina

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María Peña-Chocarro

2015-01-01

Full Text Available Cissampelos andromorpha DC. y C. arenicolaM. Nee & R. Ortiz se citan por primera vez para la flora Argentina. Se presentan descripciones e imágenes de pliegos de herbario de las especies mencionadas y se actualizan sus distribuciones geográficas. Se incluye una clave para la identificación de las cuatro especies de Cissampelospresentes en Argentina

Conflicto socioambiental y agronegocio: análisis histórico del conflicto en Malvinas Argentinas, Córdoba, Argentina.

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Leandro Carlos Barros

2016-12-01

Full Text Available En el presente artículo nos proponemos reflexionar sobre las formas de resistencia surgidas debido a los complejos procesos socioeconómicos y políticos vinculados a la expansión de los agronegocios, en el marco de la consolidación de un capitalismo extractivo en  gran parte de los países de América Latina.  Analizaremos en perspectiva sociohistórica el conflicto socioambiental en la localidad de Malvinas Argentinas, provincia de Córdoba, Argentina, en torno a la pretensión de la empresa Monsanto de radicar allí una planta de procesamiento de maíz transgénico. Para esto, pondremos el foco en la organización en asambleas de los actores sociales movilizados contra la instalación, en las acciones desplegadas y en el carácter multiescalar del conflicto.

Argentina 1967-70. Un tentativo fallito di stabilizzazione.

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G. MAYNARD

2014-08-01

Full Text Available Between 1950 and 1966 prices in Argentina rose at an average annual rate exceeding 25 percent. There have been several attempts to stabilise the situation, notably in 1966 when the military government took command. This attempt appeared to have considerable initial success, however, by 1970 the inflation rate began to accelerate again. This article describes the nature and characteristics of the stabilisation policy pursued in 1967-69. The author explains why, despite its initial success, in the end it broke down. Implications for the structuralist-monetarist controversy are then drawn. Finally, some conclusions that can be drawn for long-run development strategy and short-run stabilisation policy in Argentina are suggested.JEL: E31, E52, E60

Fruit fly eradication: Argentina

International Nuclear Information System (INIS)

2003-01-01

Fruit exports account for 9% of Argentina's total agricultural exports and generate annually close to $450 million. This could be increased but for fruit flies that cause damage equivalent to 15% to 20% of present production value of fruit and also deny export access to countries imposing quarantine barriers. The Department of Technical Co-operation is sponsoring a programme, with technical support from the Joint FAO/IAEA Division, to eradicate the Mediterranean fruit fly using the Sterile Insect Technique (SIT). (IAEA)

Primer registro de Vespula vulgaris (Hymenoptera: Vespidae) en la Argentina

OpenAIRE

Maité MASCIOCCHI; Jacqueline R. BEGGS; James M. CARPENTER; Juan C. CORLEY

2010-01-01

Vespula vulgaris (Linnaeus) es un véspido social nativo de la región Holártica. En este trabajo reportamos la primera detección de esta especie en Argentina. Obreras de esta avispa fueron capturadas cerca de la ciudad de San Carlos de Bariloche (Argentina) en Febrero de 2010, mientras se tomaban muestras de otra avispa invasora, Vespula germanica (Fabricius) o chaqueta amarilla, de morfología externa y hábitos similares a la anteriormente mencionada. Además, detallamos algunos caracteres de i...

NOVEDADES EN CALIBRACHOA (SOLANACEAE Y NOTAS TAXONÓMICAS SOBRE EL GÉNERO PARA LA ARGENTINA

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Julián A. Greppi

2013-01-01

Full Text Available Se describe e ilustra una nueva subespecie de Calibrachoa para Argentina y Brasil: C. linoides subsp. furcata. Se excluye a C. heterophylla de la flora argentina. Se consideran a C. linearis y a Petunia thymifolia f. gracilis como nuevos sinónimos de C. thymifolia y se esclarecen interpretaciones erróneas de dos especies (C. pubescens y C. humilis, previamente citadas para Argentina. Se designan lectotipos para Fabiana thymifolia, Petunia thymifolia f. gracilis y Salpiglossis linearis (= C. thymifolia.

Brasil e Argentina: uma análise do comércio de produtos da Linha Branca

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Marcelo Gregorio

2015-06-01

Full Text Available Resumo: Este trabalho possui como objetivo analisar o comércio bilateral entre o Brasil e a Argentina, em especial, para os produtos da linha branca. Foi contextualizado os principais acordos entre os dois países, com ênfase, após a união aduaneira oriunda do Mercado Comum do Sul – MERCOSUL, como principal mecanismo para o livre comércio. Neste contexto, utilizou-se do Índice de Vantagens Comparativas Reveladas – IVCR e o Índice de Orientação Regional – IOR, no período que compreende 2002-2011. Pode-se concluir que o Brasil possui evidente competitividade em relação a indústria argentina, em função disso, foi observado no período analisado que o setor de linha branca foi alvo de medidas protecionistas por parte da Argentina. Palavras-chave: comércio, Brasil-Argentina, produtos da linha branca. *** Resumen: Este trabajo tiene como objetivo analizar el comercio bilateral entre Brasil y Argentina, en particular para los productos de línea blanca. Fue contextualizado los principales acuerdos entre los dos países, con énfasis, después de la unión aduanera que viene del Mercado Común del Sur - MERCOSUR, como el mecanismo principal para el libre comercio. En este contexto, se utilizó el Índice de Revelado comparativo Advantage - IVCR y el Índice de Orientación regional - IOR, en el período que comprende desde 2002 hasta 2011. Se pudo concluir que Brasil tiene clara competitividad contra la industria argentina, y sobre esta base, se observó durante el período analizado el sector de productos de línea blanca era el objetivo de las medidas proteccionistas de Argentina. Palabras- clave: comercio, Brasil - Argentina, productos de linea blanca. *** Abstract: This work aims to analyze bilateral trade between Brazil and Argentina, in particular, for white goods. Major agreements between the two countries, with emphasis was contextualized, after the coming of the Customs Union Southern Common Market - MERCOSUR, as the main

UNA virus: first report of human infection in Argentina Virus UNA: primeiro registro de infecção em humanos na República Argentina

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Luis Adrián Diaz

2003-04-01

Full Text Available Una virus (UNAV, Togaviridae family, is widely distributed in South America, where infections have been detected in mosquitoes and vertebrate hosts (humans, birds and horses. We analyzed human sera from Córdoba inhabitants aged 44 to 89 years and using a neutralization test, we found a prevalence of UNAV antibodies of 3.8% (3/79. The low titers detected suggest past infections probably acquired in rural areas of the Province of Córdoba (central Argentina. None sera were found positive for MAYV neutralizing antibodies. This is the first report of human infections by UNAV in Argentina.O virus Una (Togaviridae tem ampla distribuição na América do Sul, detectando-se infecções até hoje em mosquitos e hospedeiros vertebrados (humanos, aves e cavalos. Mediante a realização do teste de neutralização em soros humanos provenientes de indivíduos entre 44 e 89 anos, da cidade de Córdoba, foi detectada uma prevalência de 3,8% (3/79 de anticorpos para o vírus UNA. Nenhum soro apresentou anticorpos para o vírus Mayaro. Os títulos foram baixos demonstrando-se a presença de infecção passada. Dados epidemiológicos indicam que a infecção ocorreu em áreas rurais da província de Córdoba (centro da Argentina. Os dados aqui expostos representam o primeiro registro de infecção de humanos por vírus Una na República Argentina.

Políticas públicas para la fruticultura en Argentina, 1930-1943 Public Policies for the Fruit Growing in Argentina, 1930-1943

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María Silvia Ospital

2013-04-01

Full Text Available El cierre de los mercados internacionales para la producción agraria argentina, consecuencia de la crisis internacional de 1929, obligó al Estado a implantar una serie de medidas alternativas regulatorias de la producción y mercado internistas. Estas prácticas políticas fueron acompañadas por campañas publicitarias que apuntaban a identificar consumo de productos nacionales con una nueva versión del patriotismo. Este artículo se propone realizar algunos aportes sobre esa cuestión, centrándose en las formas en que el Estado nacional -a través del Ministerio de Agricultura- y la dirigencia política y empresarial de la provincia de Mendoza elaboraron la imagen de la Argentina frutícola, productora de uvas de mesa, naranjas y manzanas para el consumo interno, a la vez que la promovían proyectándola como un novedoso renglón de las exportaciones argentinas.The closing of international markets for Argentine agrarian production forced the Government to implement a series of alternative measures such as production and commerce public regulations, bilateral treaties and the rediscovery of possibilities of the domestic market for national products. Those political measures were supplemented by a variety of advertising campaigns aimed at identifying the consumption of domestic products with a new way of patriotism. This paper aims to make contributions to this matter, focusing in the ways in which both the national government -through its agriculture ministry- and the political and corporate leaderships in the province of Mendoza composed the image of Argentina as an important producer of grapes, oranges and apples, while at the same time they stimulated fruit as a new source of the country international commerce.

Bioprospection of marine microorganisms: potential and challenges for Argentina Bioprospección de microorganismos marinos: potencialidades y desafíos para Argentina

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Hebe M Dionisi

2012-06-01

Full Text Available The marine environments of Argentina have a remarkable extension, as well as high biological productivity and biodiversity of both macro- and microorganisms. Despite having a great potential for biotechnological applications, the microorganisms inhabiting these ecosystems remain mostly unexplored and unexploited. In this review, we study the research topics and the interactions among Argentinean laboratories, by analyzing current articles published on biotechnology-related marine microbiology by researchers of this country. In addition, we identify the challenges and opportunities for Argentina to take advantage of the genetic potential of its marine microorganisms. Finally, we suggest possible actions that could improve the development of this research field, as well as the utilization of this knowledge to solve societal needs.El medio ambiente marino de la Argentina tiene una notable extensión, como así también una alta productividad biológica y biodiversidad de macro y microorganismos. A pesar de presentar un gran potencial para aplicaciones biotecnológicas, los microorganismos que habitan estos ecosistemas permanecen mayormente inexplorados y sus propiedades aún no explotadas. En este trabajo de revisión, estudiamos los temas de investigación y las interacciones entre grupos de investigación argentinos, por medio del análisis de los artículos publicados hasta el momento en temáticas relacionadas con la aplicación biotecnológica de microorganismos marinos. Además, identificamos los desafíos y las oportunidades para que la Argentina tome ventaja del potencial genético de sus microorganismos marinos. Por último, sugerimos posibles acciones que podrían mejorar el desarrollo de este campo de estudio, como así también la utilización de este conocimiento para resolver las necesidades de la sociedad.

Tobacco Industry Dominating National Tobacco Policy Making in Argentina, 1966-2005

OpenAIRE

Sebrie, Ernesto M.; Barnoya, Joaquin; Perez-Stable, Eliseo; Glantz, Stanton A.

2005-01-01

EXECUTIVE SUMMARY Argentina accounts for 15% of total tobacco consumption in Latin America and has made the epidemiological transition to an advanced stage in the tobacco epidemic. The Southern Cone region of the Americas leads the hemisphere in tobacco attributable mortality. Argentina is a developing country with economic interests in tobacco growing and rapidly increasing tobacco use in urban areas. In 2000, smoking prevalence was 40.4% among adults- 46.8% of men and 34% of wom...

High resolution TEM of chondritic carbonaceous matter: Metamorphic evolution and heterogeneity

Science.gov (United States)

Le Guillou, Corentin; Rouzaud, Jean-Noël.; Bonal, Lydie; Quirico, Eric; Derenne, Sylvie; Remusat, Laurent

2012-03-01

The insoluble carbonaceous matter from 12 chondrites (CI, CM, CO, CV, EH, and UOC), was characterized by high resolution transmission electron microscopy (HRTEM). Besides ubiquitous nanoglobules, the insoluble organic matter from petrologic type 1 and 2 chondrites and Semarkona (LL 3.0) is composed of a highly disordered polyaromatic component. No structural differences were observed between these IOMs, in agreement with the limited thermal metamorphism they all experienced. In chondrites of petrologic type >3.0, the evolution of the IOM is controlled by the extent of thermal metamorphism. The polyaromatic layers, shorter than 1 nm in petrologic type ≤3.0 chondrites, grow up to sizes between 5 and 10 nm in petrologic type >3.6 chondrites, contributing to the increase of the degree of structural order. In addition, we find rare, but ubiquitous onion-like carbons, which may be the product of nanodiamond graphitization. The insoluble carbonaceous matter of the enstatite chondrite Sahara 97096 (EH 3) is different from the other meteorites studied here. It is more heterogeneous and displays a high abundance of graphitized particles. This may be the result of a mixture between (1) the disordered carbon located in the matrix, and (2) catalytic graphitized phases associated with metal, potentially originating from partial melting events. The structural and nanostructural evolution are similar in all IOMs. This suggests that the structure of the accreted precursors and the parent body conditions of their secondary thermal modifications (temperature, duration, and pressure) were similar. The limited degree of organization of the most metamorphosed IOMs compared with terrestrial rocks submitted to similar temperature suggests that the conditions are not favorable to graphitization processes, due to the chemical nature of the precursor or the lack of confinement pressure.

Mechanics of lung ventilation in a post-metamorphic salamander, Ambystoma Tigrinum.

Science.gov (United States)

Simons, R S; Bennett, W O; Brainerd, E L

2000-03-01

The mechanics of lung ventilation in frogs and aquatic salamanders has been well characterized, whereas lung ventilation in terrestrial-phase (post-metamorphic) salamanders has received little attention. We used electromyography (EMG), X-ray videography, standard videography and buccal and body cavity pressure measurements to characterize the ventilation mechanics of adult (post-metamorphic) tiger salamanders (Ambystoma tigrinum). Three results emerged: (i) under terrestrial conditions or when floating at the surface of the water, adult A. tigrinum breathed through their nares using a two-stroke buccal pump; (ii) in addition to this narial two-stroke pump, adult tiger salamanders also gulped air in through their mouths using a modified two-stroke buccal pump when in an aquatic environment; and (iii) exhalation in adult tiger salamanders is active during aquatic gulping breaths, whereas exhalation appears to be passive during terrestrial breathing at rest. Active exhalation in aquatic breaths is indicated by an increase in body cavity pressure during exhalation and associated EMG activity in the lateral hypaxial musculature, particularly the M. transversus abdominis. In terrestrial breathing, no EMG activity in the lateral hypaxial muscles is generally present, and body cavity pressure decreases during exhalation. In aquatic breaths, tidal volume is larger than in terrestrial breaths, and breathing frequency is much lower (approximately 1 breath 10 min(-)(1 )versus 4-6 breaths min(-)(1)). The use of hypaxial muscles to power active exhalation in the aquatic environment may result from the need for more complete exhalation and larger tidal volumes when breathing infrequently. This hypothesis is supported by previous findings that terrestrial frogs ventilate their lungs with small tidal volumes and exhale passively, whereas aquatic frogs and salamanders use large tidal volumes and and exhale actively.

UHP metamorphism recorded by kyanite-bearing eclogite in the Seve Nappe Complex of northern Jämtland, Swedish Caledonides

NARCIS (Netherlands)

Janák, M.; Van Roermund, H.; Majka, J.; Gee, D.

The first evidence for ultrahigh-pressure (UHP) metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides is recorded by kyanite-bearing eclogite, found in a basic dyke within a garnet peridotite body exposed close to the lake Friningen in northern Jämtland (central Sweden). UHP

A widening gap? The political and social organization of childcare in Argentina.

Science.gov (United States)

Faur, Eleonor

2011-01-01

This article examines how social policies and programmes implemented in Argentina shape the political and social organization of childcare. The author seeks to analyse how welfare institutions are currently responding to emerging needs, and to what extent they facilitate the defamilialization of childcare for different social classes. Because Argentina lacks a truly unified ‘care policy’, four different kinds of facilities and programmes are examined: employment-based childcare services; pre-school schemes; social assistance care services; and poverty reduction strategies. It is argued that far from offering equal rights and services with a universalist cast, these ‘caring’ institutions reflect the ethos of the current welfare model in Argentina: a fragmented set of social policies based on different assumptions for different social groups, which in turn filter down to the social organization of childcare.

Micro-Raman spectroscopy of plagioclase and maskelynite in Martian meteorites: Evidence of progressive shock metamorphism

OpenAIRE

Fritz,Jorg; Greshake,Ansgar; Stoffler,Dieter

2005-01-01

We present the first systematic Micro-Raman spectroscopic investigation of plagioclase of different degree of shock metamorphism in Martian meteorites. The equilibrium shock pressure of all plagioclase phases of seventeen unpaired Martian meteorites was determined by measuring the shock-induced reduction of the refractive index. Systematic variations in the recorded Raman spectra of the plagioclase phases correlate with increasing shock pressure. In general, the shock induced deformation of t...

Estimación de la carga de las enfermedades cardiovasculares atribuible a factores de riesgo modificables en Argentina Estimate of the cardiovascular disease burden attributable to modifiable risk factors in Argentina

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Adolfo Rubinstein

2010-04-01

Full Text Available OBJETIVO: Estimar la carga de la enfermedad, su proporción atribuible a los principales factores de riesgo cardiovascular modificables y los costos médicos directos por hospitalización, asociados con las enfermedades coronarias y los accidentes cerebrovasculares en Argentina. MÉTODOS: Se elaboró un modelo analítico a partir de los datos de mortalidad en Argentina en 2005 y la prevalencia de los principales factores de riesgo cardiovascular (hipertensión arterial, hipercolesterolemia, sobrepeso, obesidad, hiperglucemia, tabaquismo actual y pasado, sedentarismo y consumo inadecuado de frutas y verduras. Se estimaron la carga de la enfermedad -años potenciales de vida perdidos (APVP y años de vida saludable (AVISA perdidos- y los costos de hospitalización por las enfermedades cardiovasculares analizadas. RESULTADOS: En 2005 se perdieron en Argentina más de 600 000 AVISA y se contabilizaron casi 400 000 APVP por enfermedades coronarias y accidentes cerebrovasculares; 71,1% de los AVISA perdidos, 73,9% de APVP y 76,0% de los costos asociados son atribuibles a facto-res de riesgo modificables. La hipertensión arterial fue el factor de riesgo de mayor impacto, tanto en hombres como en mujeres: 37,3% del costo total, 37,5% de los APVP y 36,6% de los AVISA perdidos. CONCLUSIONES: La mayor parte de la carga de la enfermedad en Argentina por enfermedades cardiovasculares está relacionada con factores de riesgo modificables -por lo tanto evitables- y podría reducirse mediante intervenciones poblacionales y clínicas basadas en un enfoque de riesgo, que ya han demostrado ser efectivas en función del costo, asequibles y factibles en países como Argentina.OBJETIVE: Estimate the burden of disease, the proportion attributable to the principal modifiable cardiovascular risk factors, and the direct medical cost of hospitalization associated with coronary heart disease and stroke in Argentina. METHODOLOGY: An analitical model was prepared using

Seismic evidence for multiple-stage exhumation of high/ultrahigh pressure metamorphic rocks in the eastern Dabie orogenic belt

Science.gov (United States)

Luo, Yinhe; Zhao, Kaifeng; Tang, Chi-Chia; Xu, Yixian

2018-05-01

The Dabie-Sulu orogenic belt in China contains one of the largest exposures of high and ultrahigh pressure (HP and UHP) metamorphic rocks in the world. The origin of HP/UHP metamorphic rocks and their exhumation to the surface in this belt have attracted great interest in the geologic community because the study of exhumation history of HP/UHP rocks helps to understand the process of continental-continental collision and the tectonic evolution of post-collision. However, the exhumation mechanism of the HP-UHP rocks to the surface is still contentious. In this study, by deploying 28 broadband seismic stations in the eastern Dabie orogenic belt and combining seismic data from 40 stations of the China National Seismic Network (CNSN), we image the high-resolution crustal isotropic shear velocity and radial anisotropy structure using ambient noise tomography. Our high-resolution 3D models provide new information about the exhumation mechanism of HP/UHP rocks and the origin of two dome structures.

Catálogo de hongos gasteroides (Basidiomycota de Catamarca, Argentina Catalogue of gasteroid fungi (Basidiomycota from Catamarca, Argentina

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María Marta Dios

2011-06-01

Full Text Available Se realiza un listado de los hongos gasteroides de la provincia de Catamarca (Argentina basado en la bibliografía hasta abril de 2010. En total aparecen citadas 43 especies distribuidas en 2 órdenes, 4 familias y 13 géneros. El número de especies catalogadas es relativamente baja pero este número probablemente se incremente cuando se estudien las zonas aún no muestreadas como son las regiones fitogeográfícas de la Puna y las Yungas.A compiled check list of gasteroid fungi of Catamarca Province (Argentina was made. It was based on literature records, available until April 2010. There were 43 species of fungi distributed in 2 orders, 4 families and 13 genera. The number of species recorded in this area was relatively poor but it is likely to increase with the study of unexplored areas not yet surveyed as the phytogeographical regions of the Puna and Yungas.

An innovative approach for testing bioinformatics programs using metamorphic testing

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Liu Huai

2009-01-01

Full Text Available Abstract Background Recent advances in experimental and computational technologies have fueled the development of many sophisticated bioinformatics programs. The correctness of such programs is crucial as incorrectly computed results may lead to wrong biological conclusion or misguide downstream experimentation. Common software testing procedures involve executing the target program with a set of test inputs and then verifying the correctness of the test outputs. However, due to the complexity of many bioinformatics programs, it is often difficult to verify the correctness of the test outputs. Therefore our ability to perform systematic software testing is greatly hindered. Results We propose to use a novel software testing technique, metamorphic testing (MT, to test a range of bioinformatics programs. Instead of requiring a mechanism to verify whether an individual test output is correct, the MT technique verifies whether a pair of test outputs conform to a set of domain specific properties, called metamorphic relations (MRs, thus greatly increases the number and variety of test cases that can be applied. To demonstrate how MT is used in practice, we applied MT to test two open-source bioinformatics programs, namely GNLab and SeqMap. In particular we show that MT is simple to implement, and is effective in detecting faults in a real-life program and some artificially fault-seeded programs. Further, we discuss how MT can be applied to test programs from various domains of bioinformatics. Conclusion This paper describes the application of a simple, effective and automated technique to systematically test a range of bioinformatics programs. We show how MT can be implemented in practice through two real-life case studies. Since many bioinformatics programs, particularly those for large scale simulation and data analysis, are hard to test systematically, their developers may benefit from using MT as part of the testing strategy. Therefore our work

Explosive volcanism, shock metamorphism and the K-T boundary

International Nuclear Information System (INIS)

Desilva, S.L.; Sharpton, V.L.

1988-01-01

The issue of whether shocked quartz can be produced by explosive volcanic events is important in understanding the origin of the K-T boundary constituents. Proponents of a volcanic origin for the shocked quartz at the K-T boundary cite the suggestion of Rice, that peak overpressures of 1000 kbars can be generated during explosive volcanic eruptions, and may have occurred during the May, 1980 eruption of Mt. St. Helens. Attention was previously drawn to the fact that peak overpressures during explosive eruptions are limited by the strength of the rock confining the magma chamber to less than 8 kbars even under ideal conditions. The proposed volcanic mechanisms for generating pressures sufficient to shock quartz are further examined. Theoretical arguments, field evidence and petrographic data are presented showing that explosive volcanic eruptions cannot generate shock metamorphic features of the kind seen in minerals at the K-T boundary

The heavy water production plant at Arroyito, Argentina

International Nuclear Information System (INIS)

Ecabert, R.

1984-01-01

The author describes the construction of an industrial heavy water production plant (Planta Industrial de Agua Pesada, PIAP) in Argentina. The heavy water enrichment is based on a hydrogen/ammonia isotope exchange. (Auth.)

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The Punta del Este terrain and its volcano sedimentary cover, metamorphic and sedimentary: geology, geochemistry and geochronology

International Nuclear Information System (INIS)

Preciozzi, F.

2015-01-01

Gariep belt it develops over the West Africa coastal region of Namibia underlying on Namaqua metamorphic complex.It characterized by supra crustal rocks affected for a very low to low metamorphism and in two tecto no-stratigraphic units identified by Base i et al 2005 showing that sediments of Formation Rocha in Uruguay and the Group Oranjemund Gariep in S E Africa have similar ages in the provenance of the zircons, suggesting that they were probably deposited in the same basin. This unit exhibits detrital zircons around 600my, sedimentation and metamorphism and deformación occur in a narrow time interval from 600-610 to 574 m (Granite de Castillo intrusion) .Cam pal et al, 2005 proposed to the Cerros Aguirre Formation similar in a range of age of different events. To the east separated from the Punta del Este Terrane –Pelotas. Aigua .Florianopolis batholith s by the shear zone Alferez Cordillera (Preciozzi et al. 1999, Basei et al. 2000) Another option develops this granitic belt is an integral part of Land Punta del Este Terrane(Preciozzi in this work), being deployed on a thin cratonic granite edge. The climax of the post-brasilian magmatism is 580my, strongly related to trans current movements (eg shear zones Major Gercino-Alferez- Cordillera and Sierra Ballena.In South America an old west domain is formed by the Piedra Alta Terrane which integrate the Río de la Pl ata Craton, a central domain intensely reworked by Neoproterozoic events known so far as Nico Perez . The primary coverage is integrated by two volcano-sedimentary basins (San Carlos Formation and Cerros de Aguirre Formation)In this study are considered the Geology,Geochemistry and Geochronology of the different units of Rocha Formation

Nuevo hospedador de Huequenia livida (Coleoptera: Cerambycidae en Argentina New host record for Huequenia livida (Coleoptera: Cerambycidae in Argentina

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José María Villacide

2006-07-01

Full Text Available La presencia de adultos de Huequenia livida (Germain, 1898 (Cerambycidae fue detectada en una plantación de Pinus contorta Douglas ex Loudon var. murrayana (Balf. Engelm. en la localidad de Lago Puelo (Chubut, Argentina. Este es el primer registro del desarrollo de H. livida en una especie hospedadora distinta de Araucaria spp. Esta contribución agrega una nueva especie y una nueva familia al listado de plantas hospedadoras descriptas para este Cerambycidae en Chile.Adult of Huequenia livida (Germain, 1898 (Cerambycidae were captured in a Pinus contorta Douglas ex Loudon var. murrayana (Balf. Engelm. plantation located in Lago Puelo ( Chubut , Argentina . This is the first mention of the development of H. livida on a host species different than Araucaria spp. This contribution also adds a new host species and family to the list of host plants described for this Cerambycidae in Chile .

Comparison of different pathways in metamorphic graded buffers on GaAs substrate: Indium incorporation with surface roughness

International Nuclear Information System (INIS)

Kumar, Rahul; Mukhopadhyay, P.; Bag, A.; Jana, S. Kr.; Chakraborty, A.; Das, S.; Mahata, M. Kr.; Biswas, D.

2015-01-01

Highlights: • In(Al,Ga)As metamorphic buffers on GaAs have been grown. • Surface morphology, strain relaxation and compositional variation have been studied. • Al containing buffers shows inferior surface roughness. • Surface roughness modulates the indium incorporation rate. - Abstract: In this work, compositionally graded In(Al,Ga)As metamorphic buffers (MBs) on GaAs substrate have been grown by MBE through three different paths. A comparative study has been done to comprehend the effect of underlying MB on the constant composition InAlAs healing layer by analyzing the relaxation behaviour, composition and surface morphology of the grown structures. The compositional variation between the constant composition healing layers on top of graded MB has been observed in all three samples although the growth conditions have been kept same. Indium incorporation rate has been found to be dependent on underlying MB. By combining the result of atomic force microscopy, photo-luminescence and X-ray reciprocal space mapping, varying surface roughness has been proposed as the probable driving force behind different Indium incorporation rate

Comparison of different pathways in metamorphic graded buffers on GaAs substrate: Indium incorporation with surface roughness

Energy Technology Data Exchange (ETDEWEB)

Kumar, Rahul, E-mail: rkp203@gmail.com [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Mukhopadhyay, P. [Rajendra Mishra School of Engineering Entrepreneurship, Indian Institute of Technology, Kharagpur 721302 (India); Bag, A.; Jana, S. Kr. [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Chakraborty, A. [Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721 302 (India); Das, S.; Mahata, M. Kr. [Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721302 (India); Biswas, D. [Department of Electronics and Electrical Communication Engineering, Indian Institute of Technology, Kharagpur 721 302 (India)

2015-01-01

Highlights: • In(Al,Ga)As metamorphic buffers on GaAs have been grown. • Surface morphology, strain relaxation and compositional variation have been studied. • Al containing buffers shows inferior surface roughness. • Surface roughness modulates the indium incorporation rate. - Abstract: In this work, compositionally graded In(Al,Ga)As metamorphic buffers (MBs) on GaAs substrate have been grown by MBE through three different paths. A comparative study has been done to comprehend the effect of underlying MB on the constant composition InAlAs healing layer by analyzing the relaxation behaviour, composition and surface morphology of the grown structures. The compositional variation between the constant composition healing layers on top of graded MB has been observed in all three samples although the growth conditions have been kept same. Indium incorporation rate has been found to be dependent on underlying MB. By combining the result of atomic force microscopy, photo-luminescence and X-ray reciprocal space mapping, varying surface roughness has been proposed as the probable driving force behind different Indium incorporation rate.

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Program: Governance and Justice ... Region: Argentina, Brazil, Chile, Costa Rica, Paraguay, Uruguay ... Program: Food, Environment, and Health ... and Twitter are having a direct bearing on social inclusion and opportunity in many spheres of ...

The Politics of Human Rights in Argentina

OpenAIRE

Brysk, Alison

2013-01-01

Revised edition of 1994 out-of-print Stanford University Press study of human rights protest, social change, and democratization in Argentina.  A symbolic politics analysis of the truth commission, trials, and policy reform in Latin America's most sweeping transition of the 1980's.

Primera cita de Aleiodes laphygmae (Hymenoptera: Braconidae para Argentina y de su asociación con larvas de Spodoptera eridania (Lepidoptera: Noctuidae First record of Aleiodes laphygmae (Hymenoptera: Braconidae for Argentina and its association with larvae of Spodoptera eridania (Lepidoptera: Noctuidae

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Liliana Valverde

2012-06-01

Full Text Available Se reporta por primera vez para Argentina Aleiodes laphygmae (Viereck (Hymenoptera: Braconidae y como parasitoide de larvas de Spodoptera eridania (Stoll (Lepidoptera: Noctuidae, en plantaciones de soja en la provincia de Tucumán (Argentina. Se provee información biológica como hábitos, hospedadores y distribución.Aleiodes laphygmae (Viereck (Hymenoptera: Braconidae, is reported for the first time for Argentina. It is also reported parasitizing larvae of Spodoptera eridania (Stoll (Lepidoptera: Noctuidae in soybeans crops in Tucumán province (Argentina. Biological information on habits, hosts and distribution is provided.

The future of the history of psychology in Argentina and Brazil.

Science.gov (United States)

Klappenbach, Hugo; Jacó-Vilela, Ana Maria

2016-08-01

This article analyzes the development of the history of psychology in Argentina and Brazil, beginning with the emergence of the history of psychology at the beginning of the 20th century. The paper analyzes that such old historical reconstructions were written by the same authors or institutions that were introducing Psychology in the two countries. That is, the older historical productions in the field of psychology were Whig biased. An analysis of the last 30 years of history of psychology is also provided. The article describes institutional developments, including archives, journals, scientific meetings, and teaching of history of psychology in academic settings. Main groups devoted to history of psychology, both in Argentina and Brazil are described. Finally, it offers some thoughts on the future of history of psychology in the 2 countries. A comparative study between Argentina and Brazil allows to understand strengths and weakness related to institutionalization of History of Psychology. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Toxigenic potential of Fusarium graminearum isolated from maize of northwest Argentina

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D.A. Sampietro

2013-01-01

Full Text Available Twenty six isolates of Fusarium graminearum from grains of maize hybrids harvested in ±west Argentina were grown on autoclaved rice grain to assess their ability to produce type B trichothecenes. Chemical analysis indicated that 38% of isolates were nivalenol (NIV producers only, 31% were major NIV producers with high DON(deoxynivalenol/NIV ratios, 8% were major DON producers with minor NIV production, and 23% were DON producers only. Isolates showed a high variability in their toxigenic potential which was not related to fungal biomass. The distribution of the different chemotypes as well as the high and the low trichothecene-producing Fusarium isolates could not be associated to a geographical origin. Our results confirmed for the first time that isolates of Fusarium graminearum from maize of northwest Argentina are able to produce DON and NIV. A substancial contamination with both NIV and DON is likely in maize from northwest Argentina. Their contents should be quantified in regional surveillances for mycotoxin contamination.

Primer registro de Vespula vulgaris (Hymenoptera: Vespidae en la Argentina

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Maité MASCIOCCHI

2010-01-01

Full Text Available Vespula vulgaris (Linnaeus es un véspido social nativo de la región Holártica. En este trabajo reportamos la primera detección de esta especie en Argentina. Obreras de esta avispa fueron capturadas cerca de la ciudad de San Carlos de Bariloche (Argentina en Febrero de 2010, mientras se tomaban muestras de otra avispa invasora, Vespula germanica (Fabricius o chaqueta amarilla, de morfología externa y hábitos similares a la anteriormente mencionada. Además, detallamos algunos caracteres de identificación y características biológicas.

Cryptosporidium varanii infection in leopard geckos (Eublepharis macularius) in Argentina.

Science.gov (United States)

Dellarupe, A; Unzaga, J M; Moré, G; Kienast, M; Larsen, A; Stiebel, C; Rambeaud, M; Venturini, M C

2016-01-01

Cryptosporidiosis is observed in reptiles with high morbidity and considerable mortality. The objective of this study was to achieve the molecular identification of Cryptosporidium spp. in pet leopard geckos (Eublepharis macularius) from a breeder colony in Buenos Aires, Argentina. Oocysts comparable to those of Cryptosporidium spp. were detected in three geckos with a history of diarrhea, anorexia and cachexia. Molecular identification methods confirmed the presence of Cryptosporidium varanii (syn. C. saurophilum). This agent was considered to be the primary cause of the observed clinical disease. This is the first description of C. varanii infection in pet reptiles in Argentina.

Cryptosporidium varanii infection in leopard geckos (Eublepharis macularius in Argentina

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A. Dellarupe

2016-06-01

Full Text Available Cryptosporidiosis is observed in reptiles with high morbidity and considerable mortality. The objective of this study was to achieve the molecular identification of Cryptosporidium spp. in pet leopard geckos (Eublepharis macularius from a breeder colony in Buenos Aires, Argentina. Oocysts comparable to those of Cryptosporidium spp. were detected in three geckos with a history of diarrhea, anorexia and cachexia. Molecular identification methods confirmed the presence of Cryptosporidium varanii (syn. C. saurophilum. This agent was considered to be the primary cause of the observed clinical disease. This is the first description of C. varanii infection in pet reptiles in Argentina.

El financiamiento bancario de las PYMES en Argentina (2002 - 2009)

OpenAIRE

Cecilia Allami; Alan Cibils

2011-01-01

Entre 2003 y 2007, la economía argentina experimentó una de las fases de crecimiento más intensas y extensas de las últimas décadas. En este nuevo escenario, las pequeñas y medianas empresas (PYMES) tuvieron un notable desempeño económico y recuperaron el dinamismo que habían perdido en la década anterior. No obstante, la limitación de acceso a los mercados de crédito por parte de las PYMES en Argentina es un fenómeno ampliamente reconocido, que compromete las posibilidades de crecimiento y e...

El financiamiento bancario de las PYMEs en Argentina (2002-2009)

OpenAIRE

Allami, Cecilia; Cibils, Alan

2011-01-01

Entre 2003 y 2007, la economía argentina experimentó una de las fases de crecimiento más intensas y extensas de las últimas décadas. En este nuevo escenario, las pequeñas y medianas empresas (PYMEs) tuvieron un notable desempeño económico y recuperaron el dinamismo que habían perdido en la década anterior. No obstante, la limitación de acceso a los mercados de crédito por parte de las PYMEs en Argentina es un fenómeno ampliamente reconocido, que compromete las posibilidades de crecimiento y e...

RERTR activities in Argentina

International Nuclear Information System (INIS)

Adelfang, P.; Alvarez, L.; Boero, N.; Calabrese, R.; De La Fuente, M.; Echenique, P.; Markiewicz, M.; Pasqualini, E.; Perez, A.; Piazza, A.; Ruggirello, G.; Taboada, H.

2000-01-01

The Atomic Energy Commission of Argentina has been involved in the Reduced Enrichment for Research and Test Reactors Program since 1978. The most relevant milestones of the program, regarding fuel R and D activities, were the development and manufacturing at industrial scale of U 3 O 8 dispersed fuel assemblies and the conversion of the RA-3 reactor core to LEU fuel. More recently, the activities were focused in the development of high density U 3 Si 2 fuel with a density of 4.8 gU/cm 3 and the improvement of the manufacturing process of U 3 Si 2 powder. Currently one of the main objectives is to develop and qualify the technology for the production of high-density LEU fuel elements using U-Mo alloy. Several alternative ways to obtain U-Mo powder are under development with the aim of evaluating plant scale production and costs. To boost this program the main research reactor of Argentina, the RA-3, will be upgraded to 10 MW early in 2001 and the hot cells at the Ezeiza Atomic Center are fully operational after important investments. Significant progresses were also carried out in the development of LEU targets for the production of Mo 99 . Experimental work has demonstrated the feasibility of the manufacturing and radiochemical processing of miniplate targets prepared with dispersed UAl x , maintaining the geometry and the alkaline processing of the HEU targets used so far. (author)

Education in acoustics in Argentina

Science.gov (United States)

Miyara, Federico

2002-11-01

Over the last decades, education in acoustics (EA) in Argentina has experienced ups and downs due to economic and political issues interfering with long term projects. Unlike other countries, like Chile, where EA has reached maturity in spite of the acoustical industry having shown little development, Argentina has several well-established manufacturers of acoustic materials and equipment but no specific career with a major in acoustics. At the university level, acoustics is taught as a complementary--often elective--course for careers such as architecture, communication engineering, or music. In spite of this there are several research centers with programs covering environmental and community noise, effects of noise on man, acoustic signal processing, musical acoustics and acoustic emission, and several national and international meetings are held each year in which results are communicated and discussed. Several books on a variety of topics such as sound system, architectural acoustics, and noise control have been published as well. Another chapter in EA is technical and vocational education, ranging between secondary and postsecondary levels, with technical training on sound system operation or design. Over the last years there have been several attempts to implement master degrees in acoustics or audio engineering, with little or no success.

Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Maláguide Complex (Betic Cordillera, Spain)

Czech Academy of Sciences Publication Activity Database

Ruiz Cruz, M. D.; Novák, Jiří Karel

2003-01-01

Roč. 15, č. 1 (2003), s. 1-14 ISSN 0935-1221 Grant - others:Ministerio de Educación y Cultura(ES) BTE-2000-1150; Research Group(ES) RNM-199 Institutional research plan: CEZ:AV0Z3013912 Keywords : low-grade metamorphism * vermiculite * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.185, year: 2003

Especies del género Tamarix (Tamaricaceae invadiendo ambientes naturales y seminaturales en Argentina Tamarix species (Tamaricaceae invading natural and seminatural habitats in Argentina

Directory of Open Access Journals (Sweden)

E. S. Natale

2008-07-01

Full Text Available El género Tamarix incluye especies con antecedentes como invasores agresivos en ambientes naturales de Estados Unidos, México y Australia. Su presencia en Argentina es conocida desde hace mucho tiempo, cultivado como ornamental, cortina corta-vientos o para sombra o creciendo de manera espontánea. Estudios previos citan un número variable de especies del género como cultivadas en el país, este trabajo aclara confusiones relacionadas con sinonimias, confirmando la presencia de cuatro especies en el país: T. gallica, T. ramosissima, T. chinensis y T. parviflora, las tres primeras registradas colonizando ambientes naturales o seminaturales. Se describen las especies del género citadas para Argentina y se provee una clave para su identificación. Se presenta la distribución conocida hasta el momento del género y se incluyen mapas con la ubicación de poblaciones establecidas e invasoras de cada especie a nivel nacional.The genus Tamarix includes species behaving as aggressive invaders in the USA, México and Australia. Previous studies report a variable number of species of this genus cultivated in Argentina as ornamentals, wind-break or for shadow, or growing spontaneously. This work makes clear some confusion related to synonyms and confirms the presence of four species in our country: T. gallica, T. ramosissima, T. chinensis and T. parviflora, the former three recorded colonizing natural and semi-natural habitats. A description of these species is given, together with a key for their identification, and information of their geographical distribution in Argentina, including maps showing the occurrence of established and invasive populations.

A new species of Miroculis (Ephemeroptera: Leptophlebiidae from NE Argentina Una nueva especie de Miroculis (Ephemeroptera: Leptophlebiidae del NE de Argentina

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Eduardo Domínguez

2007-12-01

Full Text Available The genus Miroculis Edmunds has species described from Brazil, Colombia, Peru, Venezuela and Suriname, with additional records from other countries in northern South America. In this paper, Miroculis (Ommaethus misionensis sp. nov. is described from male and female imagos from Misiones Province, NE Argentina. This constitutes the Southernmost record for the genus.El género Miroculis Edmunds tiene especies registradas en Brasil, Colombia, Perú, Venezuela y Surinam, con registros adicionales de otros países en el norte de América del Sur. En este trabajo se describe la especie Miroculis (Ommaethus misionensis sp. nov. de machos y hembras imago, de la provincia de Misiones, en el Noreste de Argentina, lo que constituye el registro más austral para el género.

Status of the forensically important genus Ophyra (Diptera: Muscidae in Argentina Estado del género de importancia forense Ophyra (Diptera: Muscidae en Argentina

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Luciano D. Patitucci

2010-06-01

Full Text Available The genus Ophyra Robineau-Desvoidy is a necrophagous group of Muscidae distributed in warm climates worldwide. The information here presented is based on the compilation of distributional data obtained from material of different collections and bibliography for Argentina. Ophyra albuquerquei Lopes, Ophyra capensis (Wiedemann, Ophyra chalcogaster (Wiedemann and Ophyra solitaria Albuquerque were recorded for the first time for the country. A key for the Argentinean species is presented. Biological and forensic data of species are discussed.El género Ophyra Robineau-Desvoidy es un grupo de múscidos necrófagos distribuidos en los climas cálidos de todo el mundo. La información aquí presentada se basa en la recopilación de datos de distribución, obtenida a partir del material de diferentes colecciones y bibliografía para la Argentina. Ophyra albuquerquei Lopes, Ophyra capensis (Wiedemann, Ophyra chalcogaster (Wiedemann y Ophyra solitaria Albuquerque se registraron por primera vez para el país. Se presenta una clave para las especies argentinas. Se discuten los datos biológicos y forenses de las distintas especies.

How Belgium helped establish a surveillance programme for Argentina's Atucha-2

Energy Technology Data Exchange (ETDEWEB)

Mitev, Lubomir [NucNet, Brussels (Belgium)

2015-02-15

Collaboration between Belgian experts and Argentina on the commissioning of Argentine reactors helped overcome problems caused by delays with construction. Marc Scibetta, deputy manager for nuclear materials science, from the Belgian Nuclear Research Centre (SCK CEN) gave an interview in which he told some facts to Lubomir Mitev of NucNet. The cooperation between SCK CEN an Argentina's Comision Nacional de Energia Atomica (CNEA) started in 2002. The first project was a support for the safety evaluation of the Atucha-1 reactor pressure vessel. When Argentina resumed the construction of Atucha-2 in 2006 - originally, construction started in 1981 but was suspended in 1985 due to financial reasons -, SCK CEN was asked to develop and implement a surveillance programme for the unit.

Argentina: Corrupción, dependencia y medios

Directory of Open Access Journals (Sweden)

Alicia Simeoni

2015-01-01

Full Text Available Señala la autora que los medios con factores de poder pero no son parte del poder mismo. Analiza la corrupción en el gobierno de Menem (1989 Argentina, el caso Swiftgate y más hechos de corrupción.

Urban agriculture: Rosario, Argentina reaps the benefits | IDRC ...

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

2010-10-06

Oct 6, 2010 ... Urban agriculture: Rosario, Argentina reaps the benefits ... Urban agriculture has become a permanent part of the city's fabric, ... The Global Roundtable of Chief Economists highlights global trends and best practices to help ...

The industrial nuclear fuel cycle in Argentina

International Nuclear Information System (INIS)

Koll, J.H.; Kittl, J.E.; Parera, C.A.; Coppa, R.C.; Aguirre, E.J.

1977-01-01

The nuclear power program of Argentina for the period 1976-85 is described, as a basis to indicate fuel requirements and the consequent implementation of a national fuel cycle industry. Fuel cycle activities in Argentina were initiated as soon as 1951-2 in the prospection and mining activities through the country. Following this step, yellow-cake production was initiated in plants of limited capacity. National production of uranium concentrate has met requirements up to the present time, and will continue to do so until the Sierra Pintada Industrial Complex starts operation in 1979. Presently, there is a gap in local production of uranium dioxide and fuel elements for the Atucha power station, which are produced abroad using Argentine uranium concentrate. With its background, the argentine program for the installation of nuclear fuel cycle industries is described, and the techno-economical implications considered. Individual projects are reviewed, as well as the present and planned infrastructure needed to support the industrial effort [es

Spent fuel management of NPPs in Argentina

International Nuclear Information System (INIS)

Alvarez, D.E.; Lee Gonzalez, H.M.

2010-01-01

There are two Nuclear Power Plants in operation in Argentina: 'Atucha I' (unique PHWR design) in operation since 1974, and 'Embalse' (typical Candu reactor) which started operation in 1984. Both NPPs are operated by 'Nucleoelectrica Argentina S.A' which is responsible for the management and interim storage of spent fuel till the end of the operative life of the plants. A third NPP, 'Atucha II' is under construction, with a similar design of Atucha I. The legislative framework establishes that after final shutdown of a NPP the spent fuel will be transferred to the 'National Atomic Energy Commission', which is also responsible for the decommissioning of the Plants. In Atucha I, the spent fuel is stored underwater, until another option is implemented meanwhile in Embalse the spent fuel is stored during six years in pools and then it is moved to a dry storage. A decision about the fuel cycle back-end strategy will be taken before year 2030. (authors)

Argentina and Brazil: an evolving nuclear relationship

International Nuclear Information System (INIS)

Redick, J.R.

1990-01-01

Argentina and Brazil have Latin America's most advanced nuclear research and power programs. Both nations reject the Non-Proliferation Treaty (NPT), and have not formally embraced the Tlatelolco Treaty creating a regional nuclear-weapon-free zone. Disturbing ambiguities persist regarding certain indigenous nuclear facilities and growing nuclear submarine and missile capabilities. For these, and other reasons, the two nations are widely considered potential nuclear weapon states. However both nations have been active supporters of the International Atomic Energy Agency (IAEA) and have, in recent years, assumed a generally responsible position in regard to their own nuclear export activities (requiring IAEA safeguards). Most important, however, has been the advent of bilateral nuclear cooperation. This paper considers the evolving nuclear relationship in the context of recent and dramatic political change in Argentina and Brazil. It discusses current political and nuclear developments and the prospects for maintaining and expanding present bilateral cooperation into an effective non-proliferation arrangement. (author)

Public information activities in Argentina

International Nuclear Information System (INIS)

Espejo, Hector

1998-01-01

This is a presentation involving a description of the main guidelines and conditions under which nuclear activities have been performed in Argentina, both concerning the autonomous development for the peaceful use of nuclear energy and with regard to the way in which the community was informed of the attained levels. The particulars of each approach are shown as to delineate historical evolution as a function of the various stages of technological development. (author)

The text of the agreement between the Agency and Argentina relating to the application of safeguards

International Nuclear Information System (INIS)

1995-01-01

The Agreement between the Republic of Argentina, the Federative Republic of Brazil, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials and the International Atomic Energy Agency for the Application of Safeguards came into force on 4 March 1994. As a result of the coming into force of the aforesaid Agreement for Argentina, the application of safeguards under the Agreement of 23 October 1973 between Argentina and the IAEA relating to the application of safeguards has been suspended

Tributación del Sector Transporte en Argentina

OpenAIRE

Ernesto Rezk

2004-01-01

El objetivo general es examinar la carga tributaria efectiva sobre los servicios y las inversiones en infraestructura en los sectores de actividad del Transporte de Carga Terrestre (por camión) y Aéreo en la Argentina.

Adding seismic broadband analysis to characterize Andean backarc seismicity in Argentina

Science.gov (United States)

Alvarado, P.; Giuliano, A.; Beck, S.; Zandt, G.

2007-05-01

Characterization of the highly seismically active Andean backarc is crucial for assessment of earthquake hazards in western Argentina. Moderate-to-large crustal earthquakes have caused several deaths, damage and drastic economic consequences in Argentinean history. We have studied the Andean backarc crust between 30°S and 36°S using seismic broadband data available from a previous ("the CHARGE") IRIS-PASSCAL experiment. We collected more than 12 terabytes of continuous seismic data from 22 broadband instruments deployed across Chile and Argentina during 1.5 years. Using free software we modeled full regional broadband waveforms and obtained seismic moment tensor inversions of crustal earthquakes testing for the best focal depth for each event. We also mapped differences in the Andean backarc crustal structure and found a clear correlation with different types of crustal seismicity (i.e. focal depths, focal mechanisms, magnitudes and frequencies of occurrence) and previously mapped terrane boundaries. We now plan to use the same methodology to study other regions in Argentina using near-real time broadband data available from the national seismic (INPRES) network and global seismic networks operating in the region. We will re-design the national seismic network to optimize short-period and broadband seismic station coverage for different network purposes. This work is an international effort that involves researchers and students from universities and national government agencies with the goal of providing more information about earthquake hazards in western Argentina.

Vacuna contra la fiebre hemorrágica argentina Candid#1 producida en la Argentina: Inmunogenicidad y seguridad Candid#1 vaccine against Argentine Hemorrhagic Fever produced in Argentina: Immunogenicity and safety

Directory of Open Access Journals (Sweden)

Delia A. Enria

2010-06-01

Full Text Available Se realizó un estudio clínico en 946 voluntarios humanos sanos, donde se comparó la vacuna Candid#1 producida en Argentina con la elaborada en EE.UU., que había sido utilizada en estudios previos. Como objetivo primario se evaluó la equivalencia en la eficacia utilizando como marcador subrogante a la inmunogenicidad medida por detección de anticuerpos neutralizantes. Como objetivo secundario se evaluó la equivalencia en inocuidad comparando las tasas de reacciones adversas. Ambas vacunas mostraron una tasa equivalente de inmunogenicidad ligeramente superior al 95.5%, que es la eficacia estimada para Candid #1 en estudios previos. No se observaron eventos adversos graves relacionados con la vacuna. Los eventos adversos generales considerados relacionados fueron de escasa significación clínica y de resolución espontánea o con tratamiento sintomático; se presentaron en los receptores de ambas vacunas en tasas equivalentes (29.9% para la vacuna fabricada en la Argentina y 35.0% para la fabricada en EE.UU., e incluyeron: cefalea, decaimiento, mialgias, plaquetopenia leve (A clinical study in 946 human volunteers was done to compare Candid #1 vaccine manufactured in Argentina with the vaccine produced in USA that had been previously used. The efficacy was evaluated using immunogenicity measured by the detection of neutralizing antibodies as a subrogate marker. Safety was evaluated comparing the rate of adverse events. Both vaccines showed a comparable rate of seroconversion, slighty higher than the efficacy estimated from previous studies (95.5%. There were no severe adverse events related to the vaccines. The general events considered related to the vaccines were not clinically relevant and disappeared either spontaneously or with symptomatic treatment. Similar rates of adverse events (29.9% for the Argentine vaccine and 35.0% for the USA vaccine were found for both vaccines. These included: headache, weakness, myalgias, mild low blood

Argentina and Brazil's Relations to the EU

DEFF Research Database (Denmark)

Christensen, Steen Fryba

Analysen diskuterer Argentina og Brasiliens relationer til EU i nyere tid med udgangspunkt i forhandlingerne om en associeringsaftale mellem EU og Mercosur, der igangsattes efter underskrivelsen af en bi-regional rammeaftale i 1995. Fokus er i særlig grad på, hvordan disse relationer bedst forstås...

Argentina - Women Weaving Equitable Gender Relations

OpenAIRE

Stubbs, Josefina

2008-01-01

In 2001, after a long period of recession, Argentina faced the greatest economic, political, and institutional crisis in its history. Unemployment reached levels nearing 18 percent and the poverty rate reached a peak of 58 percent in 2002, increasing twofold the number of people living the poverty line and impacting in a disproportionate manner the most vulnerable and poverty stricken fami...

State regulation of nuclear sector: comparative study of Argentina and Brazil models; Regulacao estatal do setor nuclear: estudo comparativo dos modelos da Argentina e do Brasil

Energy Technology Data Exchange (ETDEWEB)

Monteiro Filho, Joselio Silveira

2004-08-01

This research presents a comparative assessment of the regulation models of the nuclear sector in Argentina - under the responsibility of the Autoridad Regulatoria Nuclear (ARN), and Brazil - under the responsibility of Comissao Nacional de Energia Nuclear (CNEN), trying to identify which model is more adequate aiming the safe use of nuclear energy. Due to the methodology adopted, the theoretical framework resulted in criteria of analysis that corresponds to the characteristics of the Brazilian regulatory agencies created for other economic sector during the State reform staring in the middle of the nineties. Later, these criteria of analysis were used as comparison patterns between the regulation models of the nuclear sectors of Argentina and Brazil. The comparative assessment showed that the regulatory structure of the nuclear sector in Argentina seems to be more adequate, concerning the safe use of nuclear energy, than the model adopted in Brazil by CNEN, because its incorporates the criteria of functional, institutional and financial independence, competence definitions, technical excellence and transparency, indispensable to the development of its functions with autonomy, ethics, exemption and agility. (author)

Rb-Sr measurements on metamorphic rocks from the Barro Alto Complex, Goias, Brazil

International Nuclear Information System (INIS)

Fuck, R.A.; Neves, B.B.B.; Cordani, U.G.; Kawashita, K.

1988-01-01

The Barro Alto Complex comprises a highly deformed and metamorphosed association of plutonic, volcanic, and sedimentary rocks exposed in a 150 x 25 Km boomerang-like strip in Central Goias, Brazil. It is the southernmost tip of an extensive yet discontinuous belt of granulite and amphibolite facies metamorphic rocks which include the Niquelandia and Cana Brava complexes to the north. Two rock associations are distinguished within the granulite belt. The first one comprises a sequence of fine-grained mafic granulite, hypersthene-quartz-feldspar granulite, garnet quartzite, sillimanite-garnet-cordierite gneiss, calc-silicate rock, and magnetite-rich iron formation. The second association comprises medium-to coarse-grained mafic rocks. The medium-grade rocks of the western/northern portion (Barro Alto Complex) comprise both layered mafic rocks and a volcanic-sedimentary sequence, deformed and metamorphosed under amphibolite facies conditions. The fine-grained amphibolite form the basal part of the Juscelandia meta volcanic-sedimentary sequence. A geochronologic investigation by the Rb-Sr method has been carried out mainly on felsic rocks from the granulite belt and gneisses of the Juscelandia sequence. The analytical results for the Juscelandia sequence are presented. Isotope results for rocks from different outcrops along the gneiss layer near Juscelandia are also presented. In conclusion, Rb-Sr isotope measurements suggest that the Barro Alto rocks have undergone at least one important metamorphic event during Middle Proterozoic times, around 1300 Ma ago. During that event volcanic and sedimentary rocks of the Juscelandia sequence, as well as the underlying gabbro-anorthosite layered complex, underwent deformation and recrystallization under amphibolite facies conditions. (author)

La incipiente formación de la identidad popular en el primer kirchnerismo en Argentina (2003-2007

Directory of Open Access Journals (Sweden)

Sebastián Barbosa

2012-06-01

Full Text Available This Paper analyses discursive formation realized for government in Argentina 2003-2007 for lustered the form that the Kirchnerism in Argentina presents like popular identity. The approach intent supersede macro politics investigations for include in a new analytics line, discursive, capable to light the specifically dynamics who a government form your politic identity. The hypothesis affirms discursive formations in Argentina are like populist at the Laclau theoretical model in your hegemony theory.

The Politics of Access to Higher Education in Argentina and Brazil: A Comparative Analysis

Science.gov (United States)

Fernandes Nogueira, Jaana Flavia

2013-01-01

Historically, higher education has played an important role in the development of societies. Indeed, this has been the case in both Argentina and Brazil. The overall goal of this dissertation is to examine the historical development and the current situation of higher education in Argentina and Brazil. In relation to history, it discusses the…

Novidades taxonômicas em Maytenus (Celastraceae para a flora da Argentina

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Leonardo Biral

2014-01-01

Full Text Available No decorrer dos estudos taxonômicos de Maytenus Molina desenvolvidos pelo autor para a América do Sul, novidades taxonômicas para a flora argentina são apresentadas. Essas novidades incluem três sinonimizações, cinco lectotipificações e um novo registro de ocorrência no país. Dessa forma objetiva-se atualizar as informações disponíveis sobre o presente táxon na Argentina.

[First report of Echinococcus vogeli in a paca in Misiones province, Argentina].

Science.gov (United States)

Vizcaychipi, Katherina A; Helou, Marcia; Dematteo, Karen; Macchiaroli, Natalia; Cucher, Marcela; Rosenzvit, Mara; D'Alessandro, Antonio

2013-01-01

We report the first finding of Echinococcus vogeli in a paca, Cuniculus paca, in the tropical forest of Misiones, in the north of Argentina. The presence of the bush dog, Speothos venaticus, E. vogelís only natural definitive host, was also reported. The polycystic hydatids, 2 to 3 cm in diameter, were only found in the liver of an adult paca. The size range of the hooks and the relative proportion blade/handle did not show significant differences with respect to the ones reported for E. vogeli. The size of E. granulosus hooks, measured for comparison purposes, was significantly smaller (p E. vogeli in Argentina. The probability of finding neotropical echinococcosis in humans reinforces the need to expand the search for E. vogeli in Argentina. Echinococcosis due to E. vogeli is very aggressive and may cause death in about a third of the human population affected.

Foreign and Domestic Investment in Argentina: The Politics of Privatized Infrastructure, By Alison E. Post

DEFF Research Database (Denmark)

Manzetti, Luigi

2016-01-01

Book review of: Alison E. Post: Foreign and Domestic Investment in Argentina: The Politics of Privatized Infrastructure. Cambridge, 2014. 266 p. ISBN: 9781107048041......Book review of: Alison E. Post: Foreign and Domestic Investment in Argentina: The Politics of Privatized Infrastructure. Cambridge, 2014. 266 p. ISBN: 9781107048041...