14 research outputs found

    Central Santa Catarina coastal dunefields chronology and their relation to relative sea level and climatic changes

    Get PDF
    During the past decades, there have been contrarian explanations for the formation and stabilization of coastal dunefields: while many authors believe the dunes formation would be enhanced by falling sea level, others argue that a rising or stable sea level context would be favorable. For Brazilian coastal dunefields, the second hypothesis seems to be more consistent with the luminescence ages found so far; however, most of these data were obtained without using the SAR protocol. Another point of concern is the role of climate change in the aeolian system, which is still not very clear. The aim of this paper is to try to clarify these two questions. To this end, five coastal dunefields were selected in central Santa Catarina coast. The remote sensing and dating results allowed the discrimination and mapping of at least four aeolian generations. Their age distribution in relation to the global curve of relative sea level variation during the Late Pleistocene allows us to suggest that the formation of Aeolian dunefields in the coastal context is supported by stable relative sea level. However, relative sea level is not the only determinant for the formation and preservation of the aeolian coastal dunes. Evidences of climatic control indicate that the initiation of dunefields would be favored by periods of less humidity while their stabilization would occur preferably during the periods of rain intensification, connected to monsoon activity

    Incised valley paleoenvironments interpreted by seismic stratigraphic approach in Patos Lagoon, Southern Brazil

    Get PDF
    <div><p>ABSTRACT: The Rio Grande do Sul (RS) coastal plain area (33,000 km 2 ) had its physiography modified several times through the Quaternary, responding to allogenic and autogenic forcings. The Patos Lagoon covers a significant area of RS coastal plain (10,000 km 2 ), where incised valleys were identified in previous works. About 1,000 km of high resolution (3.5 kHz) seismic profiles, radiocarbon datings, Standard Penetration Test (SPT) and gravity cores were analyzed to interpret the paleoenvironmental evolution as preserved in incised valley infills. Seismic facies were recognized by seismic parameters. The sediment cores were used to ground-truth the seismic interpretations and help in the paleoenvironmental identification. Key surfaces were established to detail the stratigraphical framework, and seismic facies were grouped into four seismic units, which one classified in respective system tracts within three depositional sequences. The oldest preserved deposits are predominantly fluvial and estuarine facies, representing the falling stage and lowstand system tracts. The Holocene transgressive records are dominated by muddy material, mainly represented by estuarine facies with local variations. The transgression culminated in Late Holocene deposits of Patos Lagoon, representing the highstand system tract. The depositional pattern of the vertical succession was controlled by eustatic variations, while the autogenic forcing (paleogeography and sediment supply) modulated the local facies variation.</p></div

    Mapping subnational HIV mortality in six Latin American countries with incomplete vital registration systems

    Get PDF
    BackgroundHuman immunodeficiency virus (HIV) remains a public health priority in Latin America. While the burden of HIV is historically concentrated in urban areas and high-risk groups, subnational estimates that cover multiple countries and years are missing. This paucity is partially due to incomplete vital registration (VR) systems and statistical challenges related to estimating mortality rates in areas with low numbers of HIV deaths. In this analysis, we address this gap and provide novel estimates of the HIV mortality rate and the number of HIV deaths by age group, sex, and municipality in Brazil, Colombia, Costa Rica, Ecuador, Guatemala, and Mexico.MethodsWe performed an ecological study using VR data ranging from 2000 to 2017, dependent on individual country data availability. We modeled HIV mortality using a Bayesian spatially explicit mixed-effects regression model that incorporates prior information on VR completeness. We calibrated our results to the Global Burden of Disease Study 2017.ResultsAll countries displayed over a 40-fold difference in HIV mortality between municipalities with the highest and lowest age-standardized HIV mortality rate in the last year of study for men, and over a 20-fold difference for women. Despite decreases in national HIV mortality in all countries-apart from Ecuador-across the period of study, we found broad variation in relative changes in HIV mortality at the municipality level and increasing relative inequality over time in all countries. In all six countries included in this analysis, 50% or more HIV deaths were concentrated in fewer than 10% of municipalities in the latest year of study. In addition, national age patterns reflected shifts in mortality to older age groups-the median age group among decedents ranged from 30 to 45years of age at the municipality level in Brazil, Colombia, and Mexico in 2017.ConclusionsOur subnational estimates of HIV mortality revealed significant spatial variation and diverging local trends in HIV mortality over time and by age. This analysis provides a framework for incorporating data and uncertainty from incomplete VR systems and can help guide more geographically precise public health intervention to support HIV-related care and reduce HIV-related deaths.Peer reviewe

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

    Get PDF
    Anemia is a globally widespread condition in women and is associated with reduced economic productivity and increased mortality worldwide. Here we map annual 2000–2018 geospatial estimates of anemia prevalence in women of reproductive age (15–49 years) across 82 low- and middle-income countries (LMICs), stratify anemia by severity and aggregate results to policy-relevant administrative and national levels. Additionally, we provide subnational disparity analyses to provide a comprehensive overview of anemia prevalence inequalities within these countries and predict progress toward the World Health Organization’s Global Nutrition Target (WHO GNT) to reduce anemia by half by 2030. Our results demonstrate widespread moderate improvements in overall anemia prevalence but identify only three LMICs with a high probability of achieving the WHO GNT by 2030 at a national scale, and no LMIC is expected to achieve the target in all their subnational administrative units. Our maps show where large within-country disparities occur, as well as areas likely to fall short of the WHO GNT, offering precision public health tools so that adequate resource allocation and subsequent interventions can be targeted to the most vulnerable populations.Peer reviewe

    Anemia prevalence in women of reproductive age in low- and middle-income countries between 2000 and 2018

    Get PDF

    Mapping subnational HIV mortality in six Latin American countries with incomplete vital registration systems

    Get PDF
    Background: Human immunodeficiency virus (HIV) remains a public health priority in Latin America. While the burden of HIV is historically concentrated in urban areas and high-risk groups, subnational estimates that cover multiple countries and years are missing. This paucity is partially due to incomplete vital registration (VR) systems and statistical challenges related to estimating mortality rates in areas with low numbers of HIV deaths. In this analysis, we address this gap and provide novel estimates of the HIV mortality rate and the number of HIV deaths by age group, sex, and municipality in Brazil, Colombia, Costa Rica, Ecuador, Guatemala, and Mexico. Methods: We performed an ecological study using VR data ranging from 2000 to 2017, dependent on individual country data availability. We modeled HIV mortality using a Bayesian spatially explicit mixed-effects regression model that incorporates prior information on VR completeness. We calibrated our results to the Global Burden of Disease Study 2017. Results: All countries displayed over a 40-fold difference in HIV mortality between municipalities with the highest and lowest age-standardized HIV mortality rate in the last year of study for men, and over a 20-fold difference for women. Despite decreases in national HIV mortality in all countries�apart from Ecuador�across the period of study, we found broad variation in relative changes in HIV mortality at the municipality level and increasing relative inequality over time in all countries. In all six countries included in this analysis, 50 or more HIV deaths were concentrated in fewer than 10 of municipalities in the latest year of study. In addition, national age patterns reflected shifts in mortality to older age groups�the median age group among decedents ranged from 30 to 45 years of age at the municipality level in Brazil, Colombia, and Mexico in 2017. Conclusions: Our subnational estimates of HIV mortality revealed significant spatial variation and diverging local trends in HIV mortality over time and by age. This analysis provides a framework for incorporating data and uncertainty from incomplete VR systems and can help guide more geographically precise public health intervention to support HIV-related care and reduce HIV-related deaths

    Progradation rates of coastal barriers estimated from the 14C age of soil organic matter

    No full text
    10 páginas.-- 8 figuras.-- 2 tablas.-- 49 referencias© 2015 John Wiley & Sons, Ltd. The antecedent geomorphological and structural framework combined with nearshore dynamics and sediment budget provided the conditions necessary for the formation of coastal plains along the southern Brazilian littoral during the Holocene. To establish a temporal framework for littoral accretion, we applied 14C dating of humic organic material from the B-horizon of spodosols. The dated soils developed under Atlantic tropical forest, which covers the coastal barriers along the Santa Catarina shoreline of south-east Brazil. The obtained ages point to a highly coherent trend in barrier accretion and indicate that the transfer of organic matter from the surface to the B-horizon has largely been occurring vertically at the same time as the sediment surface was colonized by Atlantic forest. Accretion of the strandplain in the coastal cell of Volta Velha began ca. 6800 cal a BP, initially at a rate of ca. 22cm a-1 and reaching 58cm a-1 during the last 3 ka. Structural analysis of the dated humic material was by analytical pyrolysis and solid-state 13C nuclear magnetic resonance spectroscopy. Both techniques revealed marked compositional differences between the organic matter of different ages, which are discussed in terms of time-dependent degradation processes.This study was supported by CNPq grant No. 472897/2010–1 and 477945/2012–0, CAPES grant PVE 060/2012 (T.B.), and CNPq research grants (R.J.A. and E.G.B.). We thank Karl Statteger and one anonymous reviewer for their valuable comments, which helped to improve this paper. Simon Connor kindly corrected the original manuscript. All authors contributed to this work in equal proportion.Peer Reviewe

    Alterações morfológicas foliares em abacaxizeiros cv. IAC "Gomo-de-mel" micropropagados e aclimatizados em diferentes condições de luminosidade Morphological alterations in leave of micropropagated pineapple plants cv. IAC "Gomo-de-mel" acclimatizated in different conditions of luminosity

    Get PDF
    Plantas micropropagadas geralmente apresentam dificuldades de adaptação ao meio ex vitro, sendo muitas vezes submetidas a processos de rustificação para minimizar os impactos decorrentes da mudança de ambiente. Uma vez que a folha e seus anexos destacam-se como importantes indicativos das estratégias adaptativas das plantas a ambientes adversos, este trabalho teve por objetivo comparar a anatomia foliar de plantas de abacaxi cv. IAC "Gomo-de-mel" cultivadas in vitro com microplantas aclimatizadas em diferentes condições de luminosidade, sob telado com 50% de sombreamento e em pleno sol para verificar a necessidade do processo de rustificação para este cultivar. Avaliações por meio de microscopia de luz e eletrônica de varredura da epiderme foliar, demonstraram aumento na densidade de escamas em ambas as superfícies das folhas, em microplantas dos ambientes ex vitro, principalmente em relação às que foram expostas diretamente ao sol. Observou-se ainda, aumento no espessamento da cutícula, na sinuosidade das células epidérmicas, e na distribuição e quantidade de fibras no mesofilo evidenciando a interferência das condições de luminosidade nas características morfológicas das microplantas. Essas alterações não prejudicaram o desenvolvimento das microplantas, indicando que não são necessárias etapas de rustificação para a aclimatização deste cultivar.<br>Microprapagated plants usually show difficulties to adapt to ex vitro conditions, and many times are submitted to the rustication process to aim the reduction of all the impacts resulting from the environmental changes. Once the leaf and its annexes are important indicators of adaptability strategies of the plants to adverse environmental conditions, the objective of this work was to compare the leaf anatomy of pineapple cv. IAC "Gomo-de-mel" in vitro cultivated plants with microplants acclimatized in different conditions of luminosity, under mesh, with 50 % of shading and directly exposed to sunlight, to verify the needed of rustication process on this cultivar. Evaluations of the leaf epidermis using light and electronic scanning microscopy showed an increase on scale density in both leaves surfaces of the ex vitro microplants, mainly related to the ones directly exposed to sunlight. Subsequent observations showed an increase on cuticle thickness, on wavy contours of epidermal cells, and on the distribution and quantity of mesophyll fibers, evidencing the light conditions interference in morphological characteristics of these microplants. These alterations had not harmed microplant development, showing that are not need of rustication stages on the acclimatization process of this cultivar
    corecore