12 resultados para argentina

em Deakin Research Online - Australia


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New representatives of the family Strophalosiidae (Brachiopoda) are described from the Tupe Formation of the Paganzo Basin, Argentina. The genus Coronalosia Waterhouse & Gupta is reviewed and the new taxa Coronalosia argentinensis sp. nov. and Tupelosia paganzoensis gen. et sp. nov. proposed. The age of the Tupe Formation is reviewed and a middle to late Asselian (Early Permian) age is preferred.
The new genus Guadalupelosia from the mid-Permian of West Texas, USA, is also proposed.

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The identification and correlation of the Carboniferous-Permian (Gzhelian-Asselian) boundary within the sedimentary sequences of Gondwana has always been a topic of debate. Type latest Carboniferous and earliest Permian marine sequences are characterised by warm tropical faunas and come from the Uralian Region of Russia and Kazakhstan. Faunas include conodonts and fusulinid foraminiferids which are prime tools for correlation. Such faunal groups are absent from most Gondwanan sequences where reliance for correlations must be placed primarily on brachiopods, bivalve molluscs and palynology. The Western Australian marine sequences, with their contained ammonoids, provide a pivotal link for the dating and correlating of Early Permian Gondwanan sequences with those of the type regions and their palynostratigraphical record is essential for trans-Australian correlations and correlations elsewhere throughout Gondwanaland.

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The productid brachiopod genus Jakutoproductus, dominant in the Early Permian marine faunas of northeastern Siberia, is described for the first time from the southern hemisphere. Jakutoproductus australis sp. nov. is described from the Rio Genoa Formation, Chubut Province (Patagonia), Argentina. The age of the Patagonian species is considered to be Sakmarian (Early Permian), possibly Sterlitamakian.

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The brachiopod fauna from the Tupe Formation at La Herradura Creek, located on the west flank of Perico Hill, San Juan Province, Argentina, palaeogeographically belongs to the western sector of the Paganzo basin ('Guandacol embayment'). The stratigraphical section of the Tupe Formation at La Herradura Creek is the stratotype of the Tivertonia jachalensis-Streptorhynchus inaequiornatus biozone, was previously regarded as being of Late Carboniferous age but here is assigned to the earliest Permian (Asselian). We describe and review the biozone assemblage, which consists of Streptorhynchus inaequiornatus, Tivertonia jachalensis, Kochiproductus sp., Costatumulus sp., Coronalosia argentinensis, Tupelosia paganzoensis, Trigonotreta pericoensis, Septosyringothyris sp. aff. Septosyringothyris jaguelensis and Crurithyris? sp. This brachiopod assemblage is related to Indian and Australian Early Permian faunas and its presence in the La Herradura Creek section provides new evidence in support of an Asselian (Early Permian) age for the Tivertonia jachalensis-Streptorhynchus inaequiornatus biozone. This assemblage is also important for intra- and inter-basinal correlation because several of its characteristic species have been identified from other sections of the Paganzo basin and the Riacuteo Blanco basin. The proposed age for this biozone is consistent with the age of palynological data from slightly above the marine faunas from the stratotype locality.

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A review of the Permian spiriferid brachiopod genus Trigonolrela and its occurrence in the Early Permian of Argentina is provided herein. Several species are known from the Late Palaeozoic sequences of the Argentinean Precordillera. These include Trigonolrela sp. and Trigonolrela riojanensis (Lech and Acenolaza), from the Rio del Peii.on Formation (Rio Blanco Basin), Trigonolrela pericoensis (Leanza), from the Tupe Formation at the La Herradura creek locality (Paganzo Basin) and Trigonolrela sanjuanensis (Lech and Acenolaza), from Del Salto Formation (Calingasta-Uspallata Basin). These species are characterised by being small to medium sized, relatively transverse, with cardinal extremities often strongly angular. Costae are weakly bifurcated and superimposed on weakly developed lateral flank plications adjacent to the fastigium and sulcus. The Argentinean species are close to the oldest known Indian species of the genus, Trigonotreta hesdoensis (Salmi and Dutt), particularly with respect to the nature of its weakly fasciculated costae. Further study will refine the details of the relationship of the South American species with those from elsewhere in Gondwana and may permit the recognition of a distinctive lineage. The presence of the genus in Argentina in the earliest Permian is an important palaeobiogeographical observation that raises questions about the probable migration routes of the genus from the western Gondwanan South American margin to eastern Australia and India. The Precordilleran region appears to be the likely site of the first appearance of Trigonolrela. Species with relatively simple costae appeared first. These gave rise to more complex species with a more elaborate costal pattern indicating an evolutionary progression through time.

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The “Levipustula fauna” is a relatively diverse fossil assemblage composed of brachiopods, bivalves, bryozoans, gastropods and crinoids that appears in glaciomarine sequences related to the Carboniferous glacial event that affected the central-western Argentinean basins. Brachiopods that characterize this fauna have been studied in some of the classical localities of the Argentine Precordillera in San Juan province.

In the Hoyada Verde Formation, the “Levipustula fauna” is usually located immediately above the glacial diamictite horizons and appears to be associated with the mudstones facies of the postglacial transgression. From a palaeoecological study, three brachiopod subfaunas are distinguished in this formation: the lower “Neospirifer” (“Trigonotretidae” gen. nov.) subfauna, above which the more diversified Kitakamithyris subfauna occurs, and the upper Levipustula subfauna, with the dominant species being attributed to Levipustula levis Maxwell. The Hoyada Verde fauna, as well those identified in the La Capilla Formation (Cerro El Morado locality), have been proposed as the typical “Levipustula fauna”. However, in the Leoncito Formation, the “Levipustula fauna” occurs in sandstones horizons located below the glacial diamictite beds. This fauna is poorly diversified and the brachiopods are characterized by “Neospirifer” (“Trigonotretidae” gen. nov.)-Septosyringothyris assemblage and Levipustula is not abundant. This fauna has been considered a colder “pre-interglacial fauna”.

The significant taxonomic, palaeoecologic and taphonomic variations of the “Levipustula fauna”, as well as its position in the glacial sequences, suggest an important palaeoenvironmental control related to Carboniferous glacial dynamics. From the palaeobiogeographic viewpoint, this fauna shows the highest affinity with the Eastern Australian basins from where it was previously described.

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A new anoplid chonetid species, Yagonia furquei sp. nov., is described from the Lower Carboniferous (late Tournaisian–early Viséan) Malimán Formation of western Argentina. The associated temperate ‘Malimanian’ fauna is suggested to indicate an initial biotic segregation that took place in western Gondwana (southwestern South America), a palaeobiogeographic event that predated the late Viséan global cooling and associated major palaeolatitudinal biotic differentiation. Occurrences of Yagonia are here interpreted as evidence of a ‘south to north’ faunal migration pathway, here named the Austropanthalassic–Rheic oceanic corridor, established in western Gondwana during the late Early Carboniferous.

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The diagnosis and composition of the brachiopod Tribe Levipustulini Lazarev, 1985 is reviewed, leading to a detailed revision of the genera Levipustula Maxwell, 1951 and Lanipustula Klets, 1983, as well as a review of previous records of the species Levipustula levis Maxwell from Australia and Argentina. The presence of Lanipustula patagoniensis Simanauskas in Patagonia is confirmed with additional topotypic material described and illustrated. Based on this review, we reassign Levipustula levis from New South Wales, Australia to Lanipustula. Two new species, Lanipustula kletsi from the middle Pennsylvanian of Patagonia and the Absenticostinin Absenticosta bruntoneileenae from the latest Viséan of western Argentina, are proposed. Abstenticosta bruntoneileenae is suggested as a possible ancestral stock of the Patagonian Levipustulini through the lineage Lanipustula-Verchojania-Jakutoproductus-Piatnitzkya (Serpukhovian-middle Artinskian). The development of similar phylogenetic lineages of Levipustulini in high latitude regions of both northern and southern hemispheres (such as Siberia in Northeast Asia and Patagonia in southwestern Gondwana) is here interpreted as a consequence of parallel evolution. The progressive palaeobiogeographic isolation of Patagonia from mainland South America, coupled with its southward drift under cold palaeoclimatic conditions during middle Carboniferous-earliest Permian times, is proposed to have triggered the Levipustulini vicariance.

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To identify disparities-using recursive partitioning (RP)-in early survival for children with leukemias treated in Argentina, and to depict the main characteristics of the most vulnerable groups.

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The atmospheric quality and distribution of heavy metals were evaluated throughout a wide region of Argentina. In addition, the biomonitor performance of Tillandsia capillaris Ruiz & Pav. f. capillaris was studied in relation to the accumulation of heavy metals and to its physiologic response to air pollutants. A sampling area of 50,000 km2 was selected in the central region of the Argentine Republic. This area was subdivided into grids of 25 x 25 km. Pools of T. capillaris, where present, were collected at each intersection point. From each pool three sub-samples were analyzed independently. Furthermore, five replicates were collected at 20% of the points in order to analyze the variability within the site. The content of Co, Cu, Fe, Ni, Mn, Pb and Zn was determined by Atomic Absorption Spectrometry. Chemical-physiological parameters were also determined to detect symptoms of foliar damage. Chlorophylls, phaeophytins, hydroperoxy conjugated dienes, malondialdehyde and sulfur were quantified in T. capillaris. Some of these parameters were used to calculate a foliar damage index. Data sets were evaluated by one-way ANOVA, correlation analysis, principal component analysis and mapping. Geographical distribution patterns were obtained for the different metals reflecting the contribution of natural and anthropogenic emission sources. According to our results it can be inferred that Fe, Mn and Co probably originated in the soil. For Pb, the highest values were found in the mountainous area, which can be attributed to the presence of Pb in the granitic rocks. Ni showed mainly an anthropogenic origin, with higher values found in places next to industrial centers. For Zn the highest values were in areas of agricultural development. The same was observed for Cu, whose presence could be related to the employment of pesticides. The foliar damage index distribution map showed that the central and southeastern zones were the ones where the major damage in the bioindicator was found. The central zone coincides with the city of Córdoba whereas the southeastern area is strictly agricultural, so the high values found there could be related to the use of pesticides.

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 Introduction: Information on the epidemiology of childhood cancer in Latin America is limited. The Argentinean Oncopaediatric Registry (ROHA) is a population-based registry active since 2000. This paper describes the 3-year survival experience of children diagnosed with cancer in Argentina during 2000–2007 by major morphological subgroup, age, sex, and geographical region of residence.
Methods: Newly diagnosed paediatric cancer cases are registered in ROHA (estimated coverage is 93% of the country’s cases). Three-year overall survival was estimated using Kaplan–Meier methods. Univariate Cox models were used to compare subgroup survival.
Results: Between 2000 and 2007, a total of 10,181 new cancer diagnoses in children aged 0–14 years were reported to the registry. Three-year overall survival (95%CI) for all cancers was 61.7% (60.7; 62.7). Specific survival for the most frequent morphological types was: leukaemias 63.3% (61.6; 64.9), lymphomas and related neoplasms 75.3% (72.7; 77.7), brain neoplasms 46.3% (43.9; 48.7), soft-tissue sarcomas 52.3% (48.0; 56.5), neuroblastomas 49.6% (44.6; 54.3), renal tumours 76.7% (72.2; 80.6), and malignant bone tumours 47.2% (42.3; 51.9). Overall survival was associated with age but not sex and varied by geographical region. Compared to other regions, patients who resided in the capital city had a significantly higher survival: 69.6% (65.8; 73.0) versus 63.5% (59.4; 67.4) in Patagonia, 63.2% (61.9; 64.5) in the central region, 58.0% (54.2; 61.7) in Cuyo, 55.6% (52.5; 58.6) in the north-east, and 55.4% (52.4; 58.2) in the north-west (all P values <0.005).
Conclusions: Of children diagnosed with cancer in Argentina, 62% survived at least 3 years after diagnosis. Even though this figure is lower than that reported for more developed countries, survival patterns by diagnosis, age and sex were quite similar. Survival was lower in the two northern regions, which are areas with higher poverty levels.