The Volta Grande do Xingu: Reconstruction of Past Environments and Forecasting of Future Scenarios of a Unique Amazonian Fluvial Landscape

The Xingu River is a large clearwater river in eastern Amazonia and its downstream sector, known as the Volta Grande do Xingu (“Xingu Great Bend”), is a unique fluvial landscape that plays an important role in the biodiversity, biogeochemistry and prehistoric and historic peopling of Amazonia. The sedimentary dynamics of the Xingu River in the Volta Grande and its downstream sector will be shifted in the next few years due to the construction of dams associated with the Belo Monte hydropower project. Impacts on river biodiversity and carbon cycling are anticipated, especially due to likely changes in sedimentation and riverbed characteristics. This research project aims to define the geological and climate factors responsible for the development of the Volta Grande landscape and to track its environmental changes during the Holocene, using the modern system as a reference. In this context, sediment cores, riverbed rock and sediment samples and greenhouse gas (GHG) samples were collected in the Volta Grande do Xingu and adjacent upstream and downstream sectors. The reconstruction of past conditions in the Volta Grande is necessary for forecasting future scenarios and defining biodiversity conservation strategies under the operation of Belo Monte dams. This paper describes the scientific questions of the project and the sampling surveys performed by an international team of Earth scientists and biologists during the dry seasons of 2013 and 2014. Preliminary results are presented and a future workshop is planned to integrate results, present data to the scientific community and discuss possibilities for deeper drilling in the Xingu ria to extend the sedimentary record of the Volta Grande do Xingu

The Volta Grande do Xingu: reconstruction of past environments and forecasting of future scenarios of a unique Amazonian fluvial landscape

The Xingu River is a large clearwater river in eastern Amazonia and its downstream sector, known as the Volta Grande do Xingu ("Xingu Great Bend"), is a unique fluvial landscape that plays an important role in the biodiversity, biogeochemistry and prehistoric and historic peopling of Amazonia. The sedimentary dynamics of the Xingu River in the Volta Grande and its downstream sector will be shifted in the next few years due to the construction of dams associated with the Belo Monte hydropower project. Impacts on river biodiversity and carbon cycling are anticipated, especially due to likely changes in sedimentation and riverbed characteristics. This research project aims to define the geological and climate factors responsible for the development of the Volta Grande landscape and to track its environmental changes during the Holocene, using the modern system as a reference. In this context, sediment cores, riverbed rock and sediment samples and greenhouse gas (GHG) samples were collected in the Volta Grande do Xingu and adjacent upstream and downstream sectors. The reconstruction of past conditions in the Volta Grande is necessary for forecasting future scenarios and defining biodiversity conservation strategies under the operation of Belo Monte dams. This paper describes the scientific questions of the project and the sampling surveys performed by an international team of Earth scientists and biologists during the dry seasons of 2013 and 2014. Preliminary results are presented and a future workshop is planned to integrate results, present data to the scientific community and discuss possibilities for deeper drilling in the Xingu ria to extend the sedimentary record of the Volta Grande do Xingu

Bioelectrical impedance phase angle in clinical practice: implications for prognosis in stage IIIB and IV non-small cell lung cancer

<p>Abstract</p> <p>Background</p> <p>A frequent manifestation of advanced lung cancer is malnutrition, timely identification and treatment of which can lead to improved patient outcomes. Bioelectrical impedance analysis (BIA) is an easy-to-use and non-invasive technique to evaluate changes in body composition and nutritional status. We investigated the prognostic role of BIA-derived phase angle in advanced non-small cell lung cancer (NSCLC).</p> <p>Methods</p> <p>A case series of 165 stages IIIB and IV NSCLC patients treated at our center. The Kaplan Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle, independent of stage at diagnosis and prior treatment history.</p> <p>Results</p> <p>93 were males and 72 females. 61 had stage IIIB disease at diagnosis while 104 had stage IV. The median phase angle was 5.3 degrees (range = 2.9 – 8). Patients with phase angle <= 5.3 had a median survival of 7.6 months (95% CI: 4.7 to 9.5; n = 81), while those with > 5.3 had 12.4 months (95% CI: 10.5 to 18.7; n = 84); (p = 0.02). After adjusting for age, stage at diagnosis and prior treatment history we found that every one degree increase in phase angle was associated with a relative risk of 0.79 (95% CI: 0.64 to 0.97, P = 0.02).</p> <p>Conclusion</p> <p>We found BIA-derived phase angle to be an independent prognostic indicator in patients with stage IIIB and IV NSCLC. Nutritional interventions targeted at improving phase angle could potentially lead to an improved survival in patients with advanced NSCLC.</p

Bioelectrical impedance phase angle as a prognostic indicator in breast cancer

<p>Abstract</p> <p>Background</p> <p>Bioelectrical impedance analysis (BIA) is an easy-to-use, non-invasive, and reproducible technique to evaluate changes in body composition and nutritional status. Phase angle, determined by bioelectrical impedance analysis (BIA), detects changes in tissue electrical properties and has been hypothesized to be a marker of malnutrition. Since malnutrition can be found in patients with breast cancer, we investigated the prognostic role of phase angle in breast cancer.</p> <p>Methods</p> <p>We evaluated a case series of 259 histologically confirmed breast cancer patients treated at Cancer Treatment Centers of America. Kaplan Meier method was used to calculate survival. Cox proportional hazard models were constructed to evaluate the prognostic effect of phase angle independent of stage at diagnosis and prior treatment history. Survival was calculated as the time interval between the date of first patient visit to the hospital and the date of death from any cause or date of last contact/last known to be alive.</p> <p>Results</p> <p>Of 259 patients, 81 were newly diagnosed at our hospital while 178 had received prior treatment elsewhere. 56 had stage I disease at diagnosis, 110 had stage II, 46 had stage III and 34 had stage IV. The median age at diagnosis was 49 years (range 25 – 74 years). The median phase angle score was 5.6 (range = 1.5 – 8.9). Patients with phase angle <= 5.6 had a median survival of 23.1 months (95% CI: 14.2 to 31.9; n = 129), while those > 5.6 had 49.9 months (95% CI: 35.6 to 77.8; n = 130); the difference being statistically significant (p = 0.031). Multivariate Cox modeling, after adjusting for stage at diagnosis and prior treatment history found that every one unit increase in phase angle score was associated with a relative risk of 0.82 (95% CI: 0.68 to 0.99, P = 0.041). Stage at diagnosis (p = 0.006) and prior treatment history (p = 0.001) were also predictive of survival independent of each other and phase angle.</p> <p>Conclusion</p> <p>This study demonstrates that BIA-derived phase angle is an independent prognostic indicator in patients with breast cancer. Nutritional interventions targeted at improving phase angle could potentially lead to an improved survival in patients with breast cancer.</p

Evidence confirms an anthropic origin of Amazonian Dark Earths.

Arising from: Silva et al. Nature Communications https://doi.org/10.1038/s41467-020-20184-2 (2021

Variation of luminescence sensitivity, characteristic dose and trap parameters of quartz from rocks and sediments

We investigated the optically stimulated luminescence (OSL) and thermoluminescence (TL) characteristics of quartz from sediments and parent rocks across South America. OSL and TL sensitivities were compared with the characteristic dose of dose response curves. Additionally, we estimated electron trap parameters of quartz from sediments with contrasting OSL sensitivities. Our results show that the natural sensitivities of quartz OSL (initial 0.8 s) and TL (110 °C peak) are positively correlated and range over six and four orders of magnitude respectively. The corresponding characteristic doses range from around 30 Gy–3000 Gy for dose response curves described by a single exponential function. Quartz from igneous and metamorphic rocks and Andean short-transported sediments report low-sensitivity OSL and high characteristic dose. The studied initial OSL signal has significant contribution of medium and slow components in quartz from rocks and Andean short-transported sediments, while in quartz from Brazilian long-transported sediments, the initial OSL signal is dominated by the fast component. The trend of sensitivity increase and characteristic dose decrease is attributed to the relative contribution of medium and low components to the initial OSL emission. Regarding the electron trap parameters, high, medium and low sensitivity quartz has statistically similar values of the activation energy and the frequency factor, but both parameters have larger variations in medium and low sensitivity quartz.</p

Spatiotemporal variations of riverine discharge within the amazon basin during the late holocene coincide with extratropical temperature anomalies

Late Holocene hydroclimate variations have been extensively recognized in Amazonia, but the effects of such changes on riverine discharge within the Amazon lowlands are still poorly understood. We investigated a sediment core covering circa 4,000 to 300 cal yr BP collected in the lower valley of the Xingu River (Xingu Ria) in an area under the influence of the Amazon River. Our results indicate a decrease in precipitation in the Amazon lowlands throughout the studied period and reduced input of coarser and potassium‐rich Amazon River sediments to the confluence from about 2,600 to 1,400 cal yr BP. We suggest that lower temperatures in the extratropical Southern Hemisphere weakened the South American Summer Monsoon and led to a decrease in the water discharge of the Amazon River during this period461590139022CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES454609/2014‐0; 302607/2016‐1; 422255/2016‐5; 306527/2017‐0; 302411/2018‐61976/2014; 2043/2014; 564/20152017/50085‐3; 2014/23334‐4; 2016/11141‐2; 2016/02656‐9; 2017/25735‐4The authors acknowledge funding through the São Paulo Research Foundation (FAPESP, grants 2017/50085‐3, 2014/23334‐4, 2016/11141‐2, 2016/02656‐9, and 2017/25735‐4); the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES, grants AUXPE 1976/2014, 2043/2014, and 564/2015); and the National Council for Scientific and Technological Development (CNPq, grants 454609/2014‐0, 302607/2016‐1, 422255/2016‐5, 306527/2017‐0, and 302411/2018‐6). This work was supported through the DFG Research Center/Cluster of Excellence The Ocean in the Earth System. We thank the Paleomagnetism Laboratory (USPMag) of the University of São Paulo (Brazil). We acknowledge Ralph Kreutz for laboratory support, Daniel Atencio for providing the XRF equipment, and Mauricio Parra, Tatiana Pereira and Leandro Souza for helping during the field surveys. All data presented in this study are permanently archived on the Pangaea data repository (www.pangaea.de). The authors declare no conflict of interes

Chronology of terra firme formation in amazonian lowlands reveals a dynamic quaternary landscape

In the Amazonian lowlands, the shift from a large wetland dominated by flooded forests (Varzea) to the modern incised valleys bounded by extensive areas of non-flooded forests (Terra Firme) is considered a key driver of the Amazonian mega-biodiversity. Dating the sedimentary beds covered by Terra Firme forest is crucial to constrain the timing of such landscape change. Here we determined the formation ages of widespread regions of Terra Firme substrates in central Amazonian lowlands combining optically stimulated luminescence (OSL) dating, magnetostratigraphy and palinostratigraphy. Our data suggest a very dynamic fluvial system leading to a recent expansion of Terra Firme forests and retraction of Varzea forests during the late Pleistocene. The shift from an extensively flooded to non-flooded surface resulted from river incision around 45-35 ka, which potentially influenced the distribution of taxa by expanding available habitat, creating new barriers to dispersal, or changing the permeability of previous barriers. Transitions between flooded and non-flooded landscapes may have driven diversification and caused changes to species distributions, contributing to the high species diversity and biogeographic patterns currently found in the region. The late Quaternary evolution of Terra Firme substrates reveals that physical landscape changes play a major role in shaping biotic habitats even in the 10(4)-10(5) years time-scales210154163CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS302411/2018-6; 3009223/2014-8; 302607/2016-1; 304022/2018-7; 308927/2016-8; 454609/2014-0; 306527/2017-0; 201508/2009-5; 427280/2018-4AUXPE 2043/2014; 564/20152012/50260-6; 2016/02656-1; 2014/23334-4; 2016/09293-9; 2014/05582-0; 2015/18314-7; 16/11141-2; 2012/17517-316/2551-0000213-4We acknowledge the comments and suggestions of two anonymous reviewers, and the editorial work of J.S. Carrion. This research had the main financial support of the project “Dimensions US-BIOTA-Sao Paulo: Assembly and evolution of the Amazonian biota and its environment: an integrated approach”, a collaborative Dimensions of Biodiversity BIOTA grant supported by grant#2012/50260-6, São Paulo Research Foundation (FAPESP, Brazil), National Science Foundation (NSF, United States) and NASA (United States) 1241066 to JC. Support was also obtained from the FAPESP grant#2016/02656-1 (AOS) and the USAID-PEER Cycle 5 project History and diversification of floodplain forest bird communities in Amazonia: towards an integrated conservation plan" (CCR and JC). FNP was supported for a postdoctoral fellowship FAPESP grant#2014/23334-4 and grant#2016/09293-9 and early-career research grant from British Society for Geomorphology (United Kingdon). AKK was supported for a postdoctoral fellowship FAPESP grant#2014/05582-0 and grant#2015/18314-7. DJB is supported by FAPESP grant#16/11141-2. FNP, AOS, CMC, JFS and CCR are supported by National Council for Scientific and Technological Development (CNPq, Brazil) grants #302411/2018-6, #3009223/2014-8, #302607/2016-1, #304022/2018-7 and #308927/2016-8, respectively. GH thanks CAPES (Brazil) grant #AUXPE 2043/2014 and CNPq grants #454609/2014-0 and #306527/2017-0 for financial support. JFS thanks CNPq grants #201508/2009- 5; #427280/2018-4 and FAPERGS (Brazil) grant #16/2551-0000213-4. CMC thanks FAPESP grant #2012/17517-3 and CAPES grant #564/2015 for financial support. The authors would like to thank the Paleomagnetism Laboratory of the University of São Paulo (USPMag), Brazi