Reactive nitrogen intermediate susceptibility of Mycobacterium tuberculosis genotypes in an urban setting

BACKGROUND: Mycobacterium tuberculosis genotypes resistant to reactive nitrogen intermediates (RNI) predominate in certain urban communities, suggesting that this phenotype influences disease transmission. OBJECTIVE: To compare different M. tuberculosis genotypes for resistance to RNI generated in vitro. DESIGN: We genotyped 420 M. tuberculosis isolates from a neighborhood in Sao Paulo, Brazil, and analyzed them for susceptibility to RNI generated in acidified sodium nitrite (ASN) solution. RESULTS: Seventy-one (43%) of 167 recent-infection strains and 68 (43%) of 158 endogenous infection strains showed moderate- to high-level ASN resistance. CONCLUSION: ASN resistance of M. tuberculosis is not necessarily a determining factor for enhanced transmission.

How does a riverine setting affect the lifestyle of shellmound builders in Brazil?

The contact of inland and coastal prehistoric groups in Brazil is believed to have been restricted to regions with no geographical barrier, as is the case in the Ribeira de Iguape valley. The inland osteological collection from the riverine shellmound Moraes (5800-4500 BP) represents a unique opportunity to test this assumption for this region. Despite cultural similarities between riverine and coastal shellmounds, important ecological and site distribution differences are expected to impact on lifestyle. The purpose of this study is thus to document and interpret health and lifestyle indicators in Moraes in comparison to coastal shellmound groups. Specifically we test if the rare evidence of fish and mollusc remains in the riverine shellmound led to (a) higher caries rates and (b) lower auditory exostosis frequency and (c) if the small size of the riverine shellmound translates into reduced demographic density and thus rarity of communicable infectious diseases. Of the three hypotheses, (a) was confirmed, (b) was rejected and (c) was partly rejected. Bioanthropological similarities between Moraes and coastal shellmounds include auditory exostoses with equally high frequencies; significantly more frequent osteoarthritis in upper than in lower limbs; cranial and dental morphological affinities and low frequencies of violent trauma. However, there are also important differences: Moraes subsisted on a much broader protein diet and consumed more cariogenic food, but showed a stature even shorter than coastal groups. Thus, despite the contact also suggested by treponematoses in both site types, there was enough time for the people at the riverine site to adapt to local conditions. (c) 2008 Elsevier GmbH. All rights reserved.

Tectonic fabric revealed by AARM of the proterozoic mafic dike swarm in the Salvador city (Bahia state): Sao Francisco Craton, NE Brazil

Magnetic fabric and rock magnetism studies were performed on 25 unmetamorphosed mafic dikes of the Meso-Late Proterozoic (similar to 1.02 Ga) dike swarm from Salvador (Bahia State, NE Brazil). This area lies in the north-eastern part of the Sao Francisco Craton, which was dominantly formed/reworked during the Transamazonian orogeny (2.14-1.94 Ga). The dikes crop out along the beaches and in quarries around Salvador city, and cut across both amphibolite dikes and granulites. Their widths range from a few centimeters up to 30 m with an average of similar to 4 m, and show two main trends N 140-190 and N 100-120 with vertical dips. Magnetic fabrics were determined using both anisotropy of low-field magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM). The magnetic mineralogy was investigated by many experiments including remanent magnetization measurements at variable low temperatures (10-300 K), Mossbauer spectroscopy, high temperature magnetization curves (25-700 degrees C) and scanning electron microscopy (SEM). The rock magnetism study suggests pseudo-single-domain magnetite grains carrying the bulk magnetic susceptibility and AARM fabrics. The magnetite grains found in these dikes are large and we discard the presence of single-domain grains. Its composition is close to stoichiometric with low Ti substitution, and its Verwey transition occurs around 120 K. The main AMS fabric recognized in the swarm is so-called normal, in which the K(max)-K(int) plane is parallel to the dike plane and the magnetic foliation pole K(min)) is perpendicular to it. This fabric is interpreted as due to magma flow, and analysis of the K m inclination permitted to infer that approximately 80% of the dikes were fed by horizontal or sub-horizontal flows (K(max) < 30 degrees). This interpretation is supported by structural field evidence found in five dikes. In addition, based on the plunge of K(max), two mantle sources could be inferred; one of them which fed about 80% of the swarm would be located in the southern part of the region, and the other underlied the Valeria quarry. However, for all dikes the AARM tensors are not coaxial with AMS fabrics and show a magnetic lineation (AARM(max)) oriented to N30-60E, suggesting that magnetite grains were rotated clockwise from dike plane. The orientation of AARM lineation is similar to the orientation of a system of faults in which the Salvador normal fault is the most important. These faults were formed during Cretaceous rifting in the Reconcavo-Tucano-jatoba assemblage that corresponds to an aborted intra-continental rift formed during the opening of the South Atlantic. Therefore, the AARM fabric found for the Salvador dikes is probably tectonic in origin and suggests that the dike swarm was affected by the important tectonic event responsible for the break-up of the Gondwanaland. (C) 2008 Elsevier B.V. All rights reserved.

The Cariris Velhos tectonic event in Northeast Brazil

The Borborema Province in northeastern South America is a typical Brasiliano-Pan-African branching system of Neoproterozoic orogens that forms part of the Western Gondwana assembly. The province is positioned between the Sao Luis-West Africa craton to the north and the Sao Francisco (Congo-Kasai) craton to the south. For this province the main characteristics are (a) its subdivision into five major tectonic domains, bounded mostly by long shear zones, as follows: Medio Coreau, Ceara Central, Rio Grande do Norte, Transversal, and Southern; (b) the alternation of supracrustal belts with reworked basement inliers (Archean nuclei + Paleoproterozoic belts); and (c) the diversity of granitic plutonism, from Neoproterozoic to Early Cambrian ages, that affect supracrustal rocks as well as basement inliers. Recently, orogenic rock assemblages of early Tonian (1000-920 Ma) orogenic evolution have been recognized, which are restricted to the Transversal and Southern domains of the Province. Within the Transversal Zone, the Alto Pajeu terrane locally includes some remnants of oceanic crust along with island arc and continental arc rock assemblages, but the dominant supracrustal rocks are mature and immature pelitic metasedimentary and metavolcaniclastic rocks. Contiguous and parallel to the Alto Pajeu terrane, the Riacho Gravata subterrane consists mainly of low-grade metamorphic successions of metarhythmites, some of which are clearly turbiditic in origin, metaconglomerates, and sporadic marbles, along with interbedded metarhyolitic and metadacitic volcanic or metavolcaniclastic rocks. Both terrane and subterrane are cut by syn-contractional intrusive sheets of dominantly peraluminous high-K calc-alkaline, granititic to granodioritic metaplutonic rocks. The geochemical patterns of both supracrustal and intrusive rocks show similarities with associations of mature continental arc volcano-sedimentary sequences, but some subordinate intra-plate characteristics are also found. In both the Alto Pajeu and Riacho Gravata terranes, TIMS and SHRIMP U-Pb isotopic data from zircons from both metavolcanic and metaplutonic rocks yield ages between 1.0 and 0.92 Ga, which define the time span for an event of orogenic character, the Cariris Velhos event. Less extensive occurrences of rocks of Cariris Velhos age are recognized mainly in the southernmost domains of the Province, as for example in the Polo Redondo-Maranco terrane, where arc-affinity migmatite-granitic and meta-volcano-sedimentary rocks show U-Pb ages (SHRIMP data) around 0.98-0.97 Ga. For all these domains, Sm-Nd data exhibit Tom model ages between 1.9 and 1.1 Ga with corresponding slightly negative to slightly positive epsilon(Nd)(t) values. These domains, along with the Borborema Province as a whole, were significantly affected by tectonic and magmatic events of the Brasiliano Cycle (0.7-0.5 Ga), so that it is possible that there are some other early Tonian rock assemblages which were completely masked and hidden by these later Brasiliano events. Cariris Velhos processes are younger than the majority of orogenic systems at the end of Mesoproterozoic Era and beginning of Neoproterozoic throughout the world, e.g. Irumide belt, Kibaride belt and Namaqua-Natal belt, and considerably younger than those of the youngest orogenic process (Ottawan) in the Grenvillian System. Therefore, they were probably not associated with the proposed assembly of Rodinia. We suggest, instead, that Cariris Velhos magmatism and tectonism could have been related to a continental margin magmatic arc, with possible back-arc associations, and that this margin may have been a short-lived (<100 m.y.) leading edge of the newly assembled Rodinia supercontinent. (C) 2009 Elsevier Ltd. All rights reserved.

ASSOCIATED A-TYPE SUBALKALINE AND HIGH-K CALC-ALKALINE GRANITES IN THE ITU GRANITE PROVINCE, SOUTHEASTERN BRAZIL: PETROLOGICAL AND TECTONIC SIGNIFICANCE

The 590-580 Ma Itu Granite Province (IGP) is a roughly linear belt of post-orogenic granite plutons similar to 60 km wide extending for some 350 km along the southern edge of the Apia-Guaxupe Terrane in southeastern Brazil. Typical components are subalkaline A-type granites (some with rapakivi texture) that crystallized at varied, but mostly strongly oxidizing conditions, and contrast with a coeval association of also oxidized high-K calc-alkaline granites in terms of major (e. g., lower Ca/Fe) and trace elements (higher Nb, Y, Zr). Mantle-derived magmas (such as those forming the LILE-rich Piracaia Monzodiorite, with epsilon(Nd(t)) = -7 to -10, (87)Sr/(86)Sr((t)) = 0.7045-0.7055) are inferred to derive from enriched subcontinental lithosphere modified during previous subduction, and may have played a role in the generation of the A-type granites, adding melts or fluids or both to the lower crust from which the latter were generated. The IGP is interpreted as a reflection of crust uplift and increased heat flux during ascent of hot, less dense asthenosphere after continental collision, probably reflecting breakoff of an oceanic slab coeval to the right-lateral accretion of a terrane related to the Mantiqueira Orogenic System.

THE RIO APA CRATON IN MATO GROSSO DO SUL (BRAZIL) AND NORTHERN PARAGUAY: GEOCHRONOLOGICAL EVOLUTION, CORRELATIONS AND TECTONIC IMPLICATIONS FOR RODINIA AND GONDWANA

The Rio Apa cratonic fragment crops out in Mato Grosso do Sul State of Brazil and in northeastern Paraguay. It comprises Paleo-Mesoproterozoic medium grade metamorphic rocks, intruded by granitic rocks, and is covered by the Neoproterozoic deposits of the Corumbi and Itapocurni Groups. Eastward it is bound by the southern portion of the Paraguay belt. In this work, more than 100 isotopic determinations, including U-Pb SHRIMP zircon ages, Rb-Sr and Sm-Nd whole-rock determinations, as well as K-Ar and Ar-Ar mineral ages, were reassessed in order to obtain a complete picture of its regional geological history. The tectonic evolution of the Rio Apa Craton starts with the formation of a series of magmatic arc complexes. The oldest U-Pb SHRIMP zircon age comes from a banded gneiss collected in the northern part of the region, with an age of 1950 +/- 23 Ma. The large granitic intrusion of the Alumiador Batholith yielded a U-Pb zircon age of 1839 +/- 33 Ma, and from the southeastern part of the area two orthogneisses gave zircon U-Pb ages of 1774 +/- 26 Ma and 1721 +/- 25 Ma. These may be coeval with the Alto Terere metamorphic rocks of the northeastern corner, intruded in their turn by the Baia das Garcas granitic rocks, one of them yielding a zircon U-Pb age of 1754 +/- 49 Ma. The original magmatic protoliths of these rocks involved some crustal component, as indicated by the Sm-Nd TDm model ages, between 1.9 and 2.5 Ga. Regional Sr isotopic homogenization, associated with tectonic deformation and medium-grade metamorphism occurred at approximately 1670 Ma, as suggested by Rb-Sr whole rock reference isochrons. Finally, at 1300 Ma ago, the Ar work indicates that the Rio Apa Craton was affected by widespread regional heating, when the temperature probably exceeded 350 degrees C. Geographic distribution, age and isotopic signature of the fithotectonic units suggest the existence of a major suture separating two different tectonic domains, juxtaposed at about 1670 Ma. From that time on, the unified Rio Apa continental block behaved as one coherent and stable tectonic unit. It correlates well with the SW corner of the Amazonian Craton, where the medium-grade rocks of the Juruena-Rio Negro tectonic province, with ages between 1600 and 1780 Ma, were reworked at about 1300 Ma. Looking at the largest scale, the Rio Apa Craton is probably attached to the larger Amazonian Craton, and the actual configuration of southwestern South America is possibly due to a complex arrangement of allochthonous blocks such as the Arequipa, Antofalla and Pampia, with different sizes, that may have originated as disrupted parts of either Laurentia or Amazonia, and were trapped during later collisions of these continental masses.

Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

A paleomagnetic study was carried out on the Late Jurassic Sarmiento Ophiolitic Complex (SOC) exposed in the Magallanes fold and thrust belt in the southern Patagonian Andes (southern Chile). This complex, mainly consisting of a thick succession of pillow-lavas, sheeted dikes and gabbros, is a seafloor remnant of the Late Jurassic to Early Cretaceous Rocas Verdes basin that developed along the south-western margin of South America. Stepwise thermal and alternating field demagnetization permitted the isolation of a post-folding characteristic remanence, apparently carried by fine grain (SD?) magnetite, both in the pillow-lavas and dikes. The mean ""in situ"" direction for the SOC is Dec: 286.9 degrees, Inc: -58.5 degrees, alpha-95: 6.9 degrees, N: 11 (sites). Rock magnetic properties, petrography and whole-rock K-Ar ages in the same rocks are interpreted as evidence of correlation between remanence acquisition and a greenschist facies metamorphic overprint that must have occurred during latest stages or after closure and tectonic inversion of the basin in the Late Cretaceous. The mean remanence direction is anomalous relative to the expected Late Cretaceous direction from stable South America. Particularly, a declination anomaly over 50 degrees is suggestively similar to paleomagnetically interpreted counter clockwise rotations found in thrust slices of the Jurassic El Quemado Fm. located over 100 km north of the study area in Argentina. Nevertheless, a significant ccw rotation of the whole SOC is difficult to reconcile with geologic evidence and paleogeographic models that suggest a narrow back-arc basin sub-parallel to the continental margin. A rigid-body 30 degrees westward tilting of the SOC block around a horizontal axis trending NNW, is considered a much simpler explanation, being consistent with geologic evidence. This may have occurred as a consequence of inverse reactivation of old normal faults, which limit both the SOC exposures and the Cordillera Sarmiento to the East. The age of tilting is unknown but it must postdate remanence acquisition in the Late Cretaceous. Two major orogenic events of the southern Patagonian Andes, in the Eocene (ca. 42 Ma) and Middle Miocene (ca. 12 Ma), respectively, could have caused the proposed tilting. (C) 2008 Elsevier B.V. All rights reserved.

Precambrian geotectonic units of the Rio de La Plata craton

The main Precambrian tectonic units of Uruguay include the Piedra Alta tectonostratigraphic terrane (PATT) and Nico Perez tectonostratigraphic terrane (NPTT), separated by the Sarandi del Yi high-strain zone. Both terranes are well exposed in the Rio de La Plata craton (RPC). Although these tectonic units are geographically small, they record a wide span of geologic time. Therefore improved geological knowledge of this area provides a fuller understanding of the evolution of the core of South America. The PATT is constituted by low-to medium-grade metamorphic belts (ca. 2.1 Ga); its petrotectonic associations such as metavolcanic units, conglomerates, banded iron formations, and turbiditic deposits suggest a back-arc or a trench-basin setting. Also in the PATT, a late to post-orogenic, arc-related layered mafic complex (2.3-1.9 Ga), followed by A-type granites (2.08 Ga), and finally a taphrogenic mafic dike swarm (1.78 Ga) occur. The less thoroughly studied NPTT consists of Palaeoproterozoic high-grade metamorphic sequences (ca. 2.2 Ga), mylonites and postorogenic and rapakivi granites (1.75 Ga). The Brasiliano-Pan African orogeny affected this terrane. Neoproterozoic cover occurs in both tectonostratigraphic terranes, but is more developed in the NPTT. Over the past 15 years, new isotopic studies have improved our recognition of different tectonic events and associated processes, such as reactivation of shear zones and fluids circulation. Transamazonian and Statherian tectonic events were recognized in the RPC. Based on magmatism, deformation, basin development and metamorphism, we propose a scheme for the Precambrian tectonic evolution of Uruguay, which is summarized in the first Palaeoproterozoic tectonic map of the Rio de La Plata craton.

Application of Narrative Pedagogy to Promote Excellence in the Clinical Setting

The clinical setting has become increasingly complex in recent years. Nurse educators have recognized the limitations of traditional pedagogies in the clinical setting. The need for innovative, student-centered learning is essential in order to transfer knowledge to practical situations and discover new ways of thinking about clinical situations. Narrative pedagogy which emphasizes how students learn and experience learning is an effective evidence-based approach to clinical education.

Acceptability of home-assessment post medical abortion and medical abortion in a low-resource setting in Rajasthan, India : Secondary outcome analysis of a non-inferiority randomized controlled trial

Background: Studies evaluating acceptability of simplified follow-up after medical abortion have focused on high-resource or urban settings where telephones, road connections, and modes of transport are available and where women have formal education. Objective: To investigate women's acceptability of home-assessment of abortion and whether acceptability of medical abortion differs by in-clinic or home-assessment of abortion outcome in a low-resource setting in India. Design: Secondary outcome of a randomised, controlled, non-inferiority trial. Setting Outpatient primary health care clinics in rural and urban Rajasthan, India. Population: Women were eligible if they sought abortion with a gestation up to 9 weeks, lived within defined study area and agreed to follow-up. Women were ineligible if they had known contraindications to medical abortion, haemoglobin < 85mg/l and were below 18 years. Methods: Abortion outcome assessment through routine clinic follow-up by a doctor was compared with home-assessment using a low-sensitivity pregnancy test and a pictorial instruction sheet. A computerized random number generator generated the randomisation sequence (1: 1) in blocks of six. Research assistants randomly allocated eligible women who opted for medical abortion (mifepristone and misoprostol), using opaque sealed envelopes. Blinding during outcome assessment was not possible. Main outcome measures: Women's acceptability of home-assessment was measured as future preference of follow-up. Overall satisfaction, expectations, and comparison with previous abortion experiences were compared between study groups. Results: 731 women were randomized to the clinic follow-up group (n = 353) or home-assessment group (n = 378). 623 (85%) women were successfully followed up, of those 597 (96%) were satisfied and 592 (95%) found the abortion better or as expected, with no difference between study groups. The majority, 355 (57%) women, preferred home-assessment in the event of a future abortion. Significantly more women, 284 (82%), in the home-assessment group preferred home-assessment in the future, as compared with 188 (70%) of women in the clinic follow-up group, who preferred clinic follow-up in the future (p < 0.001). Conclusion: Home-assessment is highly acceptable among women in low-resource, and rural, settings. The choice to follow-up an early medical abortion according to women's preference should be offered to foster women's reproductive autonomy.