Fluxos de carbono orgânico e de nutrientes em Terra Preta de Indio, Terra Mulata e solos adjacentes sob floresta secundária na Amazônia Central.

Com o objetivo estimar os fluxos de carbono orgânico e nutrientes em perfis de solos de Terra Preta de Índio e solos adjacentes sob floresta secundária na Amazônia Central, o presente estudo procura identificar os solos que retém mais carbono orgânico e nutrientes

Variations in soil chemical and physical properties explain basin-wide Amazon forest soil carbon concentrations

We investigate the edaphic, mineralogical and climatic controls of soil organic carbon (SOC) concentration utilising data from 147 primary forest soils (0–30 cm depth) sampled in eight different countries across the Amazon Basin. Sampled across 14 different World Reference Base soil groups, our data suggest that stabilisation mechanism varies with pedogenetic level. Specifically, although SOC concentrations in Ferralsols and Acrisols were best explained by simple variations in clay content – this presumably being due to their relatively uniform kaolinitic mineralogy – this was not the case for less weathered soils such as Alisols, Cambisols and Plinthosols for which interactions between Al species, soil pH and litter quality are argued to be much more important. Although for more strongly weathered soils the majority of SOC is located within the aggregate fraction, for the less weathered soils most of the SOC is located within the silt and clay fractions. It thus seems that for highly weathered soils SOC storage is mostly influenced by surface area variations arising from clay content, with physical protection inside aggregates rendering an additional level of protection against decomposition. On the other hand, most of the SOC in less weathered soils is associated with the precipitation of aluminium–carbon complexes within the fine soil fraction, with this mechanism enhanced by the presence of high levels of aromatic, carboxyl-rich organic matter compounds. Also examined as part of this study were a relatively small number of arenic soils (viz. Arenosols and Podzols) for which there was a small but significant influence of clay and silt content variations on SOM storage, with fractionation studies showing that particulate organic matter may account for up to 0.60 of arenic soil SOC. In contrast to what were in all cases strong influences of soil and/or litter quality properties, after accounting for these effects neither wood productivity, above-ground biomass nor precipitation/temperature variations were found to exert any significant influence on SOC stocks. These results have important implications for our understanding of how Amazon forest soils are likely to respond to ongoing and future climate changes

Multiple phosphorus acquisition strategies adopted by fine roots in low-fertility soils in Central Amazonia

This is the final version. Available from Springer Verlag via the DOI in this record.Background and aims Ancient Amazon soils are characterised by low concentrations of soil phosphorus (P). Therefore, it is hypothesised that plants may invest a substantial proportion of their resources belowground to adjust their P-uptake strategies, including root morphological, physiological (phosphatase enzyme activities) and biotic (arbuscular mycorrhizal (AM) associations) adaptations. Since these strategies are energy demanding, we hypothesise that trade-offs between morphological traits and root phosphatase exudation and symbiotic associations would occur. Specifically, we expected that plants which invest in finer roots, and therefore have greater ability to explore large soil volumes, would have a high investment in physiological adaptations such as enhanced phosphatase production. In contrast, we expected that plants with predominantly thicker roots would invest more in symbiotic associations, in which carbon is traded for P acquired from AM fungal communities. Methods We collected absorptive roots (<2 mm diameter) from a lowland Central Amazon forest near Manaus, Brazil. We measured fine root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD), root phosphatase activity (APase) and arbuscular mycorrhizal (AM) fungi colonisation. Results Root morphological traits were related to APase activity, with higher APase activity in roots with higher SRL and SRA but lower RTD. However, the degree of AM colonisation was not related to any measured root morphological trait. Conclusions Fine absorptive roots likely benefit from having low RTD, high SRL, SRA and APase exudation to acquire P efficiently. However, because AM colonisation was not related to root morphology, we suggest that investment in multiple P-uptake strategies is required for maintaining productivity in Central Amazon forests.Natural Environment Research Council (NERC)Brazilian National Council for Scientific and Technological Development (CNPq)Australian Research Counci

Dietary Fat Patterns and Outcomes in Acute Pancreatitis in Spain

Background/Objective: Evidence from basic and clinical studies suggests that unsaturated fatty acids (UFAs) might be relevant mediators of the development of complications in acute pancreatitis (AP). Objective: The aim of this study was to analyze outcomes in patients with AP from regions in Spain with different patterns of dietary fat intake. Materials and Methods: A retrospective analysis was performed with data from 1,655 patients with AP from a Spanish prospective cohort study and regional nutritional data from a Spanish cross-sectional study. Nutritional data considered in the study concern the total lipid consumption, detailing total saturated fatty acids, UFAs and monounsaturated fatty acids (MUFAs) consumption derived from regional data and not from the patient prospective cohort. Two multivariable analysis models were used: (1) a model with the Charlson comorbidity index, sex, alcoholic etiology, and recurrent AP; (2) a model that included these variables plus obesity. Results: In multivariable analysis, patients from regions with high UFA intake had a significantly increased frequency of local complications, persistent organ failure (POF), mortality, and moderate-to-severe disease in the model without obesity and a higher frequency of POF in the model with obesity. Patients from regions with high MUFA intake had significantly more local complications and moderate-to-severe disease; this significance remained for moderate-to-severe disease when obesity was added to the model. Conclusions: Differences in dietary fat patterns could be associated with different outcomes in AP, and dietary fat patterns may be a pre-morbid factor that determines the severity of AP. UFAs, and particulary MUFAs, may influence the pathogenesis of the severity of AP

Body mass index and healthy lifestyle practices among Peruvian university students: a comparative study among academic discipline

BackgroundExcess body weight and an unhealthy lifestyle are a risk factor for noncommunicable diseases. University students are susceptible to unhealthy habits and obesity. This study compared body mass index (BMI) and healthy lifestyle practices among university students from four academic disciplines: Health Sciences, Business Sciences, Human Sciences and Education, and Engineering/Architecture.MethodsA cross-sectional study was carried out using a sample of 6,642 university students selected by non-probability convenience sampling. The Diet and Healthy Lifestyle Scale (DEVS), the Peruvian validation of the Vegetarian Lifestyle Index (VLI), was used to assess healthy lifestyle practices.ResultsStudents in the areas of Business Sciences and Engineering/Architecture had a higher BMI than their peers in Health Sciences (B = 0.35, 95% CI: 0.15–0.56 and 0.32, 95% CI: 0.13–0.52; p = 0.001). Additionally, these students tended to adopt less healthy lifestyle (B = −0.11, 95% CI: −0.20 to −0.01 and −0.09, 95% CI: −0.18 to −0.00; p &lt; 0.05) compared to those in Health Sciences.ConclusionAlthough students of Health Sciences and Human Sciences and Education exhibited healthy lifestyle patterns, there is a clear need to improve eating and living habits in general among the university population to mitigate the risk factors associated with non-communicable diseases

Intake of foods high in saturated fats, vegetarian dietary pattern, and sociodemographic characteristics associated with body weight in Peruvian university students

BackgroundThe prevalence of obesity continues to increase among university students and the general population. Consumption of a diet high in saturated fats could be one of the risk factors.ObjectiveThe consumption of foods high in saturated fats, the vegetarian diet pattern, and sociodemographic characteristics associated with excess body weight (overweight/obesity) were evaluated in Peruvian university students.MethodsA cross-sectional study was carried out selecting 5,608 Peruvian university students through no probabilistic convenience sampling. The survey was carried out during the months of February and April 2022. The Chi-square test and binary logistic regression analysis were used to evaluate the association between diet (saturated fats intake and dietary pattern) and sociodemographic factors with excess body weight in a cross-sectional analysis.ResultsIt was observed that students who reported high consumption of foods high in saturated fats (ORB = 1.14) and those who had a non-vegetarian dietary pattern (ORB = 2.76) were found to be more likely to have excess body weight. On the contrary, students who reported adherence to the vegetarian diet pattern for more than 5 years were less likely to be overweight or obese (ORB = 0.84). Being ≥26 years of age (ORB = 3.28), living in urban areas (ORB = 1.68) and coastal areas of the country (ORB = 1.17), and enrolled in the engineering faculty (ORB = 1.19), were significantly associated with excess body weight.ConclusionThe findings of the current study evidenced several factors associated with excess body weight in university students. Therefore, it is necessary to promote and implement healthy lifestyle programs, considering sociodemographic and dietary aspects such as age and dietary intake to control and prevent obesity in university students

Lagging Response of Belowground Functional Traits to Environmental Cues in a Mature Amazonian Tropical Rainforest

Context/Purpose: The stress-dominance hypothesis (SDH) is a model of community assembly predicting that the relative importance of environmental filtering increases and competition decreases along a gradient of increasing environmental stress. Therefore, trait variation at the community level should increase as resources are more available. Although the SDH was designed to explain spatial changes in plant communities based on aboveground traits, it is possible that root communities show similar switches in strategies at temporal scales in response to pulses in resource availability. Methods: To test this hypothesis we sampled for two years the morphological changes in root systems in a mature tropical forest in Central Amazon. Thirty-six samples along a 500 m transect were taken each three months from February 2016 to February 2018, separating the uppermost organic layer (0-5 cm) from the mineral soil (5-15 cm). Besides root biomass, we scanned approximately 20% of the total root systems to calculate specific root length (SRL), average diameter (D), root tissue density (RTD), and branching index (BI). Spatially, we expected shifts from acquisitive to conservative syndromes as roots penetrate in the mineral soil. Temporarily, we hypothesized that traits associated with resource acquisition (SRL, SRTA, BI) will increase with soil moisture. Moreover, we expected that trait range will increase as resources become more available. Results: We found significant differences in biomass and morphological traits between the organic and mineral soils. We found no patterns between biomass increases in seasonality, but mean community traits change significantly with seasonal rain patterns. More interestingly, changes in mean and range values were more strongly associated with rain events three months before the collecting date, suggesting a lagging between rain events and belowground community responses. Conclusions: Belowground dynamics are structured spatially and temporarily in tropical forests, in synchrony with the availability of resources, as predicted by the SHD. Our results suggest that species tend to show similar traits during stressful times but diverge during acquisition periods. The results suggest a belowground dimension to niche segregation little explored in tropical biomes to date

Associations between social network addiction, anxiety symptoms, and risk of metabolic syndrome in Peruvian adolescents—a cross-sectional study

BackgroundThe link between physical and mental health and screen time in adolescents has been the subject of scientific scrutiny in recent years. However, there are few studies that have evaluated the association between social network addiction (SNA) and metabolic risk in this population.ObjectiveThis study determined the association between SNA and anxiety symptoms with the risk of metabolic syndrome (MetS) in adolescents.MethodsA cross-sectional study was conducted in Peruvian adolescents aged 12 to 18 years, who completed a Social Network Addiction Questionnaire and the Generalized Anxiety Disorder 2-item scale (GAD-2), between September and November 2022. A total of 903 participants were included in the study using a non-probability convenience sample. Sociodemographic and anthropometric data were also collected. Binary logistic regression was used to explore the association between SNA and anxiety symptoms with MetS in a cross-sectional analysis.ResultsMales were more likely to have MetS than females (OR = 1.133, p = 0.028). Participants who were 16 years of age or older and those with excess body weight were 2.166, p = 0.013 and 19.414, p &lt; 0.001 times more likely to have MetS, respectively. Additionally, SNA (OR = 1.517, p = 0.016) and the presence of anxiety symptoms (OR = 2.596, p &lt; 0.001) were associated with MetS.ConclusionOur findings suggest associations between SNA, anxiety symptoms, and MetS among youth. However, more studies are needed to better understand this association and to deepen the possible clinical and public health implications

Direct evidence for phosphorus limitation on Amazon forest productivity

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.The authors acknowledge funding from the UK Natural Environment Research Council (NERC), grant number NE/L007223/1. This is publication 850 in the technical series of the BDFFP. C.A.Q. acknowledges the grants from Brazilian National Council for Scientific and Technological Development (CNPq) CNPq/LBA 68/2013, CNPq/MCTI/FNDCT no. 18/2021 and his productivity grant. C.A.Q., H.F.V.C., F.D.S., I.A., L.F.L., E.O.M. and S.G. acknowledge the AmazonFACE programme for financial support in cooperation with Coordination for the Improvement of Higher Education Personnel (CAPES) and the National Institute of Amazonian Research as part of the grants CAPES-INPA/88887.154643/2017-00 and 88881.154644/2017-01. T.F.D. acknowledges funds from FundacAo de Amparo a Pesquisa do Estado de SAo Paulo (FAPESP), grant 2015/50488-5, and the Partnership for Enhanced Engagement in Research (PEER) programme grant AID-OAA-A-11-00012. L.E.O.C.A. thanks CNPq (314416/2020-0)