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Tree allometric models, essential for monitoring and predicting terrestrial carbon stocks, are traditionally built on global databases with forest inventory measurements of stem diameter (D) and tree height (H). However, these databases often combine H measurements obtained through various measurement methods, each with distinct error patterns, affecting the resulting H:D allometries. In recent decades, terrestrial laser scanning (TLS) has emerged as a widely accepted method for accurate, non‐destructive tree structural measurements. This study used TLS data to evaluate the prediction accuracy of forest inventory‐based H:D allometries and to develop more accurate pantropical allometries. We considered 19 tropical rainforest plots across four continents. Eleven plots had forest inventory and RIEGL VZ‐400(i) TLS‐based D and H data, allowing accuracy assessment of local forest inventory‐based H:D allometries. Additionally, TLS‐based data from 1951 trees from all 19 plots were used to create new pantropical H:D allometries for tropical rainforests. Our findings reveal that in most plots, forest inventory‐based H:D allometries underestimated H compared with TLS‐based allometries. For 30‐metre‐tall trees, these underestimations varied from −1.6 m (−5.3%) to −7.5 m (−25.4%). In the Malaysian plot with trees reaching up to 77 m in height, the underestimation was as much as −31.7 m (−41.3%). We propose a TLS‐based pantropical H:D allometry, incorporating maximum climatological water deficit for site effects, with a mean uncertainty of 19.1% and a mean bias of −4.8%. While the mean uncertainty is roughly 2.3% greater than that of the Chave2014 model, this model demonstrates more consistent uncertainties across tree size and delivers less biased estimates of H (with a reduction of 8.23%). In summary, recognizing the errors in H measurements from forest inventory methods is vital, as they can propagate into the allometries they inform. This study underscores the potential of TLS for accurate H and D measurements in tropical rainforests, essential for refining tree allometries. [ABSTRACT FROM AUTHOR]

The Phylum Cressdnaviricota consists of a large number of circular Rep‐encoding single‐stranded (CRESS)‐DNA viruses. Recently, metagenomic analyzes revealed their ubiquitous distribution in a diverse range of eukaryotes. Data relating to CRESS‐DNA viruses in humans remains scarce. Our study investigated the presence and genetic diversity of CRESS‐DNA viruses in human vaginal secretions. Vaginal swabs were collected from 28 women between 29 and 43 years old attending a fertility clinic in New York City. An exploratory metagenomic analysis was performed and detection of CRESS‐DNA viruses was confirmed through analysis of near full‐length sequences of the viral isolates. A phylogenetic tree was based on the REP open reading frame sequences of the CRESS‐DNA virus genome. Eleven nearly complete CRESS‐DNA viral genomes were identified in 16 (57.1%) women. There were no associations between the presence of these viruses and any demographic or clinical parameters. Phylogenetic analysis indicated that one of the sequences belonged to the genus Gemycircularvirus within the Genomoviridae family, while ten sequences represented previously unclassified species of CRESS‐DNA viruses. Novel species of CRESS‐DNA viruses are present in the vaginal tract of adult women. Although they be transient commensal agents, the potential clinical implications for their presence at this site cannot be dismissed. [ABSTRACT FROM AUTHOR]

(Pb0.96La0.04)(Zr0.95Ti0.05)0.99O3 ceramics were successfully elaborated by the solid‐sate reaction method. The pure perovskite phase was obtained, comprising both rhombohedral (R3c) and orthorhombic (Pbam) crystallographic structures, as determined by x‐ray diffraction and Raman spectroscopy analyses. The rhombohedral and orthorhombic structures were carefully attributed to the ferroelectric (FE) and antiferroelectric (AFE) phases, respectively. The room temperature electromechanical performances of the samples were particularly investigated at the nanoscale level by using piezoresponse force microscopy (PFM). The measurement of PFM domain patterns evidenced spontaneous piezoelectric and ferroelectric activities as well as regions with no piezoresponse, in agreement with the coexistence of FE and AFE phases. By means of the spectroscopic mode of the PFM used in on‐ and off‐field methods, very specific piezoloops were recorded. Square‐shaped hysteresis loops for phase signal and butterfly‐like shape loops for amplitude activity were obtained under and at zero bias when probing ferroelectric regions, while on‐field piezoloops displaying double hysteresis for phase signal were detected and assigned to the stable antiferroelectric phase. Finally, the signature of metastable antiferroelectric phase was also identified through in‐field and remnant loops measurements. These results further provided the phases coexistence, concurrently unveiling intricate nanoscale electrical characteristics (both stable and metastable AFE behaviors) at room temperature. Furthermore, these data suggest that PFM proves to be a robust technique for investigating local antiferroelectricity in such complex ceramic oxides. [ABSTRACT FROM AUTHOR]

Human enteroviruses (EV) are the most common cause of aseptic meningitis worldwide. Data on EV viral load in cerebrospinal fluid (CSF) and related epidemiological studies are scarce in Brazil. This study investigated the influence of EV viral load on CSF parameters, as well as identifying the involved species. CSF samples were collected in 2018–2019 from 140 individuals at The Hospital das Clínicas, São Paulo. The EV viral load was determined using real‐time quantitative polymerase chain reaction, while EV species were identified by 5′UTR region sequencing. Median viral load was 5.72 log10 copies/mL and did not differ by subjects' age and EV species. Pleocytosis was observed in 94.3% of cases, with the highest white blood cell (WBC) counts in younger individuals. Viral load and WBC count were correlated in children (p = 0.0172). Elevated lactate levels were observed in 60% of cases and correlated with the viral load in preteen‐teenagers (p = 0.0120) and adults (p = 0.0184). Most individuals had normal total protein levels (70.7%), with higher in preteen‐teenagers and adults (p < 0.0001). By sequencing, 8.2% were identified as EV species A and 91.8% as species B. Age‐specific variations in CSF characteristics suggest distinct inflammatory responses in each group. [ABSTRACT FROM AUTHOR]

The continued functioning of tropical forests under climate change depends on their resilience to drought and heat. However, there is little understanding of how tropical forests will respond to combinations of these stresses, and no field studies to date have explicitly evaluated whether sustained drought alters sensitivity to temperature. We measured the temperature response of net photosynthesis, foliar respiration and the maximum quantum efficiency of photosystem II (Fv/Fm) of eight hyper‐dominant Amazonian tree species at the world's longest‐running tropical forest drought experiment, to investigate the effect of drought on forest thermal sensitivity. Despite a 0.6°C–2°C increase in canopy air temperatures following long‐term drought, no change in overall thermal sensitivity of net photosynthesis or respiration was observed. However, photosystem II tolerance to extreme‐heat damage (T50) was reduced from 50.0 ± 0.3°C to 48.5 ± 0.3°C under drought. Our results suggest that long‐term reductions in precipitation, as projected across much of Amazonia by climate models, are unlikely to greatly alter the response of tropical forests to rising mean temperatures but may increase the risk of leaf thermal damage during heatwaves. [ABSTRACT FROM AUTHOR]

Background and objective: Ivermectin is a known anti‐parasitic agent that has been investigated as an antiviral agent against coronavirus disease 2019 (COVID‐19). This study aimed to evaluate the efficacy of ivermectin in mild COVID‐19 patients. Methods: In this multi‐arm randomized clinical trial conducted between 9 April 2021 and 20 May 2021, a total of 393 patients with reverse transcription‐PCR‐confirmed COVID‐19 infection and mild symptoms were enrolled. Subjects were randomized in a 1:1:1 ratio to receive single‐dose ivermectin (12 mg), double‐dose ivermectin (24 mg) or placebo. The primary outcome was need for hospitalization. Results: There was no significant difference in the proportion of subjects who required hospitalization between the placebo and single‐dose ivermectin groups (absolute difference in the proportions: −2.3 [95% CI = −8.5, 4.1]) and between the placebo and double‐dose ivermectin groups (absolute difference in the proportions: −3.9 [95% CI = −9.8, 2.2]). The odds of differences in mean change in severity score between single‐dose ivermectin and placebo groups (ORdifference = 1.005 [95% CI: 0.972, 1.040]; p = 0.762) and double‐dose ivermectin and placebo groups (ORdifference = 1.010 [95% CI: 0.974, 1.046]; p = 0.598) were not statistically significant. None of the six adverse events (including mild dermatitis, tachycardia and hypertension) were serious and required extra action. Conclusion: Single‐dose and double‐dose ivermectin early treatment were not superior to the placebo in preventing progression to hospitalization and improving clinical course in mild COVID‐19. We conducted a double‐blinded randomized placebo‐controlled trial including 393 patients with mild coronavirus disease 2019 (COVID‐19) and found that ivermectin, an anti‐parasitic medication with known antiviral properties, was non‐superior to the placebo. Neither a single nor a double dose was better in preventing progression to hospitalization and worsening of the clinical course of COVID‐19 infection. [ABSTRACT FROM AUTHOR]

Presently, metallic nanowires (NWs) are the most promising materials to fabricate flexible transparent electrodes as an alternative to indium tin oxide. Here, the high performance of transparent conductive electrodes (TCEs) based on silver nanowires (AgNWs) percolation networks is reported. With optimized experimental conditions for the deposition, the AgNWs result in low sheet resistance of 10 Ω sq−1 combined with a high optical transmittance of 92.6% at λ = 550 nm. This leads to a valuable figure of merit as compared to other TCEs. In this study, the nanoscale electrical properties of the AgNWs are measured via conductive atomic force microscopy to characterize the percolation network. The electrical resistivity value calculated for a single AgNW is found to be about 12.35 µΩ cm, while a nanoscale conductivity map over an AgNW network bridging two electrodes has revealed high levels of current within the network over a distance of more than 1000 µm. The favorable determined conductivity results along with the high optical properties of the AgNWs network strongly suggest that thin‐film electrodes based on AgNWs will be a potential approach for future flexible electronic devices. [ABSTRACT FROM AUTHOR]

Citrus is among the most important crops in the world, and has suffered losses of up to 80% due to the citrus blackfly, Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae). The combined use of entomopathogenic fungi and plant extracts is a sustainable alternative to control this pest. The objectives of this study were to select entomopathogenic fungi to control A. woglumi and verify the insecticidal effect of the combined use of the selected fungi and aqueous extracts of castor bean leaves, Ricinus communis L. (Euphorbiaceae). Twenty fungal isolates obtained from field‐collected dead A. woglumi were identified and tested against the insect. Eight were identified as belonging to Fusarium incarnatum‐equiseti species complex, nine to Fusarium fujikuroi species complex, two to Cordyceps javanica (Bally) Kepler, B. Shrestha & Spatafora, and one to genus Akanthomyces. The five isolates that caused the maximum confirmed mortality were tested for compatibility with aqueous castor bean extract at 5, 10, and 20% (wt/vol) concentrations. Qualitative phytochemical analysis showed the presence of alkaloids, glycoside flavonoids, saponins, and tannins in the castor bean extract. Most of the isolates studied caused high confirmed mortality of citrus blackfly. In the compatibility tests, Fusarium volatile Al‐Hatmi, Sand.‐Den., SA Ahmed & de Hoog and Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg combined with the 5% aqueous extract were the most suitable for testing against A. woglumi. Additive interactions were observed for the combined control agents. The highest value of confirmed mortality (98.2%) was observed for the combination of 5% aqueous castor bean extract and F. volatile (URM 8051), the efficacy of which should be confirmed by field tests. [ABSTRACT FROM AUTHOR]

Enterovirus (EV) is commonly associated with central nervous system (CNS) syndromes. Recently, gastroenteric viruses, including rotavirus (RVA), human astrovirus (HAstV), and norovirus (NoV), have also been associated with CNS neurological disorders. The aim of the present study was to investigate the presence of EV, RVA, HAst, and NoV associated to CNS infections with undiagnosed etiology in Northwest region of São Paulo State, Brazil, and to conduct the molecular characterization of the positive samples detected. A total of 288 cerebrospinal fluid samples collected from July to December 2017 were tested for EV and NoV by quantitative real‐time polymerase chain reaction (RT‐qPCR), HAstV by conventional RT‐PCR, and RVA by enzyme‐linked immunosorbent assay. Positive‐EV samples were inoculated in cells lines, amplified by RT‐PCR and sequenced. RVA, NoV, and HAstV were not detected. EV infection was detected in 5.5% (16/288), and five samples successful genotyped: echovirus 3 (E3) (1/5), coxsackie virus A6 (CVA6) (1/5), and coxsackie virus B4 (CVB4) (3/5). Meningitis was the main syndrome observed (12/16; 75%). CVA6, CVB4, and E3 were identified associated with aseptic meningitis. Reports of CVA6 associated with aseptic meningitis are rare, E3 had not been previously reported in Brazil, and epidemiological data on CVB4 in the country is virtually unknown. The present investigation illustrates the circulation of diverse EV types in a small regional sample set and in a short period of time, highlighting the importance of an active EV surveillance system in CNS infections. Enhanced understanding of undiagnosed CNS infections will assist in public health and health care planning. Highlights: EV was found in 5.5% of previously undiagnosed CNS infectionsRare Echovirus 3 identified for the first time in BrazilEV exhibit epidemiological importance in aseptic meningitis casesAn EV surveillance system in CNS infections is required to monitor circulating species and types [ABSTRACT FROM AUTHOR]

Version 5 of the Community Land Model (CLM5) introduces the plant hydraulic stress (PHS) configuration of vegetation water use, which is described and compared with the corresponding parameterization from CLM4.5. PHS updates vegetation water stress and root water uptake to better reflect plant hydraulic theory, advancing the physical basis of the model. The new configuration introduces prognostic vegetation water potential, modeled at the root, stem, and leaf levels. Leaf water potential replaces soil potential as the basis for stomatal conductance water stress, and root water potential is used to implement hydraulic root water uptake, replacing a transpiration partitioning function. Point simulations of a tropical forest site (Caxiuanã, Brazil) under ambient conditions and partial precipitation exclusion highlight the differences between PHS and the previous CLM implementation. Model description and simulation results are contextualized with a list of benefits and limitations of the new model formulation, including hypotheses that were not testable in previous versions of the model. Key results include reductions in transpiration and soil moisture biases relative to a control model under both ambient and exclusion conditions, correcting excessive dry season soil moisture stress in the control model. PHS implements hydraulic gradient root water uptake, which allows hydraulic redistribution and compensatory root water uptake and results in PHS utilizing a larger portion of the soil column to buffer shortfalls in precipitation. The new model structure, which bases water stress on leaf water potential, could have significant implications for vegetation‐climate feedbacks, including increased sensitivity of photosynthesis to atmospheric vapor pressure deficit. Key Points: An updated soil‐plant‐atmosphere continuum model based on hydraulic theory is implemented in the Community Land Model (version 5)Prognostic leaf water potential replaces soil matric potential as the basis for stomatal conductance water stressPrognostic root water potential is used to implement hydraulic root water uptake, replacing a "soil wilting point" approach [ABSTRACT FROM AUTHOR]

Summary: The prediction of vegetation responses to climate requires a knowledge of how climate‐sensitive plant traits mediate not only the responses of individual plants, but also shifts in the species and functional compositions of whole communities. The emission of isoprene gas – a trait shared by one‐third of tree species – is known to protect leaf biochemistry under climatic stress. Here, we test the hypothesis that isoprene emission shapes tree species compositions in tropical forests by enhancing the tolerance of emitting trees to heat and drought. Using forest inventory data, we estimated the proportional abundance of isoprene‐emitting trees (pIE) at 103 lowland tropical sites. We also quantified the temporal composition shifts in three tropical forests – two natural and one artificial – subjected to either anomalous warming or drought. Across the landscape, pIE increased with site mean annual temperature, but decreased with dry season length. Through time, pIE strongly increased under high temperatures, and moderately increased following drought. Our analysis shows that isoprene emission is a key plant trait determining species responses to climate. For species adapted to seasonal dry periods, isoprene emission may tradeoff with alternative strategies, such as leaf deciduousness. Community selection for isoprene‐emitting species is a potential mechanism for enhanced forest resilience to climatic change. [ABSTRACT FROM AUTHOR]

Abstract: Litterfall dynamics in tropical forests are a good indicator of overall tropical forest function, indicative of carbon invested in both photosynthesising tissues and reproductive organs such as flowers and fruits. These dynamics are sensitive to changes in climate, such as drought, but little is known about the long‐term responses of tropical forest litterfall dynamics to extended drought stress. We present a 15‐year dataset of litterfall (leaf, flower and fruit, and twigs) from the world's only long‐running drought experiment in tropical forest. This dataset comprises one of the longest published litterfall time series in natural forest, which allows the long‐term effects of drought on forest reproduction and canopy investment to be explored. Over the first 4 years of the experiment, the experimental soil moisture deficit created only a small decline in total litterfall and leaf fall (12% and 13%, respectively), but a very strong initial decline in reproductive litterfall (flowers and fruits) of 54%. This loss of flowering and fruiting was accompanied by a de‐coupling of all litterfall patterns from seasonal climate variables. However, following >10 years of the experimental drought, flower and fruiting re‐stabilised at levels greater than in the control plot, despite high tree mortality in the drought plot. Litterfall relationships with atmospheric drivers were re‐established alongside a strong new apparent trade‐off between litterfall and tree growth. Synthesis. We demonstrate that this tropical forest went through an initial shock response during the first 4 years of intense drought, where reproductive effort was arrested and seasonal litterfall patterns were lost. However, following >10 years of experimental drought, this system appears to be re‐stabilising at a new functional state where reproduction is substantially elevated on a per tree basis; and there is a new strong trade‐off between investment in canopy production and wood production. [ABSTRACT FROM AUTHOR]

Summary: CO2 efflux from stems (CO2_stem) accounts for a substantial fraction of tropical forest gross primary productivity, but the climate sensitivity of this flux remains poorly understood. We present a study of tropical forest CO2_stem from 215 trees across wet and dry seasons, at the world's longest running tropical forest drought experiment site. We show a 27% increase in wet season CO2_stem in the droughted forest relative to a control forest. This was driven by increasing CO2_stem in trees 10–40 cm diameter. Furthermore, we show that drought increases the proportion of maintenance to growth respiration in trees > 20 cm diameter, including large increases in maintenance respiration in the largest droughted trees, > 40 cm diameter. However, we found no clear taxonomic influence on CO2_stem and were unable to accurately predict how drought sensitivity altered ecosystem scale CO2_stem, due to substantial uncertainty introduced by contrasting methods previously employed to scale CO2_stem fluxes. Our findings indicate that under future scenarios of elevated drought, increases in CO2_stem may augment carbon losses, weakening or potentially reversing the tropical forest carbon sink. However, due to substantial uncertainties in scaling CO2_stem fluxes, stand‐scale future estimates of changes in stem CO2 emissions remain highly uncertain. [ABSTRACT FROM AUTHOR]

Transpiration from the Amazon rainforest generates an essential water source at a global and local scale. However, changes in rainforest function with climate change can disrupt this process, causing significant reductions in precipitation across Amazonia, and potentially at a global scale. We report the only study of forest transpiration following a long-term (>10 year) experimental drought treatment in Amazonian forest. After 15 years of receiving half the normal rainfall, drought-related tree mortality caused total forest transpiration to decrease by 30%. However, the surviving droughted trees maintained or increased transpiration because of reduced competition for water and increased light availability, which is consistent with increased growth rates. Consequently, the amount of water supplied as rainfall reaching the soil and directly recycled as transpiration increased to 100%. This value was 25% greater than for adjacent nondroughted forest. If these drought conditions were accompanied by a modest increase in temperature (e.g., 1.5°C), water demand would exceed supply, making the forest more prone to increased tree mortality. [ABSTRACT FROM AUTHOR]

Abstract: Why do some forests produce biomass more efficiently than others? Variations in Carbon Use Efficiency (CUE: total Net Primary Production (NPP)/ Gross Primary Production (GPP)) may be due to changes in wood residence time (Biomass/NPPwood), temperature, or soil nutrient status. We tested these hypotheses in 14, one ha plots across Amazonian and Andean forests where we measured most key components of net primary production (NPP: wood, fine roots, and leaves) and autotrophic respiration (Ra; wood, rhizosphere, and leaf respiration). We found that lower fertility sites were less efficient at producing biomass and had higher rhizosphere respiration, indicating increased carbon allocation to belowground components. We then compared wood respiration to wood growth and rhizosphere respiration to fine root growth and found that forests with residence times <40 yrs had significantly lower maintenance respiration for both wood and fine roots than forests with residence times >40 yrs. A comparison of rhizosphere respiration to fine root growth showed that rhizosphere growth respiration was significantly greater at low fertility sites. Overall, we found that Amazonian forests produce biomass less efficiently in stands with residence times >40 yrs and in stands with lower fertility, but changes to long‐term mean annual temperatures do not impact CUE. [ABSTRACT FROM AUTHOR]

The isomorphic substitution (IS) of Al for Fe can alter many properties of Fe oxide minerals, including their aqueous solubility. The resistance of these minerals to dissolution in soils can, in turn, influence the availability of Fe and the formation of new Fe oxides. In this study, the dissolution kinetics of synthetic, Al-substituted maghemites (γ-Fe2-xAlxO3) were investigated in 2 M HCl. The IS values varied from 0.0 to 14.3 mol% Al, and the dissolution reaction was conducted under controlled temperature (20°C ± 1) over a period of 288 h. Successive, 5-mL aliquots of suspension were withdrawn after set times, and Fe and Al were analyzed by ICP-MS. The overall dissolution rates of Fe and Al were similar throughout the experiment, indicating congruent dissolution. The resulting data were described equally well by using the Kabai and Avrami-Erofejev equations. Dissolution rates considering the specific surface area (SSA), as k2 = k/SSA, were the most efficient for describing the influence of IS on mineral dissolution and demonstrated that the maghemites became more resistant to dissolution with increasing Al substitution. Observations from transmission electron microscopy (TEM) supported isotropic dissolution of individual particles. [ABSTRACT FROM AUTHOR]

The isomorphic substitution (IS) of Al for Fe can alter many properties of Fe oxide minerals, including their aqueous solubility. The resistance of these minerals to dissolution in soils can, in turn, influence the availability of Fe and the formation of new Fe oxides. In this study, the dissolution kinetics of synthetic, Al-substituted maghemites (γ-Fe2-xAlxO3) were investigated in 2 M HCl. The IS values varied from 0.0 to 14.3 mol% Al, and the dissolution reaction was conducted under controlled temperature (20°C ± 1) over a period of 288 h. Successive, 5-mL aliquots of suspension were withdrawn after set times, and Fe and Al were analyzed by ICP-MS. The overall dissolution rates of Fe and Al were similar throughout the experiment, indicating congruent dissolution. The resulting data were described equally well by using the Kabai and Avrami-Erofejev equations. Dissolution rates considering the specific surface area (SSA), as k2 = k/SSA, were the most efficient for describing the influence of IS on mineral dissolution and demonstrated that the maghemites became more resistant to dissolution with increasing Al substitution. Observations from transmission electron microscopy (TEM) supported isotropic dissolution of individual particles. [ABSTRACT FROM AUTHOR]

•At least one climate model predicts severe reductions of rainfall over Amazonia during this century. Long-term throughfall exclusion (TFE) experiments represent the best available means to investigate the resilience of the Amazon rainforest to such droughts. •Results are presented from a 7 yr TFE study at Caxiuanã National Forest, eastern Amazonia. We focus on the impacts of the drought on tree mortality, wood production and above-ground biomass. •Tree mortality in the TFE plot over the experimental period was 2.5% yr−1, compared with 1.25% yr−1 in a nearby control plot experiencing normal rainfall. Differences in stem mortality between plots were greatest in the largest (> 40 cm diameter at breast height (dbh)) size class (4.1% yr−1 in the TFE and 1.4% yr−1 in the control). Wood production in the TFE plot was c. 30% lower than in the control plot. Together, these changes resulted in a loss of 37.8 ± 2.0 Mg carbon (C) ha−1 in the TFE plot (2002–2008), compared with no change in the control. •These results are remarkably consistent with those from another TFE (at Tapajós National Forest), suggesting that eastern Amazonian forests may respond to prolonged drought in a predictable manner. [ABSTRACT FROM AUTHOR]

1. The Amazon region may experience increasing moisture limitation over this century. Leaf dark respiration ( R) is a key component of the Amazon rain forest carbon (C) cycle, but relatively little is known about its sensitivity to drought. 2. Here, we present measurements of R standardized to 25 °C and leaf morphology from different canopy heights over 5 years at a rain forest subject to a large-scale through-fall reduction (TFR) experiment, and nearby, unmodified Control forest, at the Caxiuanã reserve in the eastern Amazon. 3. In all five post-treatment measurement campaigns, mean R at 25 °C was elevated in the TFR forest compared to the Control forest experiencing normal rainfall. After 5 years of the TFR treatment, R per unit leaf area and mass had increased by 65% and 42%, respectively, relative to pre-treatment means. In contrast, leaf area index ( L) in the TFR forest was consistently lower than the Control, falling by 23% compared to the pre-treatment mean, largely because of a decline in specific leaf area ( S). 4. The consistent and significant effects of the TFR treatment on R, L and S suggest that severe drought events in the Amazon, of the kind that may occur more frequently in future, could cause a substantial increase in canopy carbon dioxide emissions from this ecosystem to the atmosphere. [ABSTRACT FROM AUTHOR]

The allocation and cycling of carbon (C) within forests is an important component of the biospheric C cycle, but is particularly understudied within tropical forests. We synthesise reported and unpublished results from three lowland rainforest sites in Amazonia (in the regions of Manaus, Tapajós and Caxiuanã), all major sites of the Large-Scale Biosphere–Atmosphere Programme (LBA). We attempt a comprehensive synthesis of the C stocks, nutrient status and, particularly, the allocation and internal C dynamics of all three sites. The calculated net primary productivities (NPP) are 10.1±1.4 Mg C ha−1 yr−1 (Manaus), 14.4±1.3 Mg C ha−1 yr−1 (Tapajós) and 10.0±1.2 Mg C ha−1 yr−1 (Caxiuanã). All errors bars report standard errors. Soil and leaf nutrient analyses indicate that Tapajós has significantly more plant-available phosphorus and calcium. Autotrophic respiration at all three sites (14.9–21.4 Mg C ha yr−1) is more challenging to measure, with the largest component and greatest source of uncertainty being leaf dark respiration. Comparison of measured soil respiration with that predicted from C cycling measurements provides an independent constraint. It shows general good agreement at all three sites, with perhaps some evidence for measured soil respiration being less than expected. Twenty to thirty percent of fixed C is allocated belowground. Comparison of gross primary productivity (GPP), derived from ecosystem flux measurements with that derived from component studies (NPP plus autotrophic respiration) provides an additional crosscheck. The two approaches are in good agreement, giving increased confidence in both approaches to estimating GPP. The ecosystem carbon-use efficiency (CUEs), the ratio of NPP to GPP, is similar at Manaus (0.34±0.10) and Caxiuanã (0.32±0.07), but may be higher at Tapajós (0.49±0.16), although the difference is not significant. Old growth or infertile tropical forests may have low CUE compared with recently disturbed and/or fertile forests. [ABSTRACT FROM AUTHOR]

Climate modelling studies predict that the rain forests of the Eastern Amazon basin are likely to experience reductions in rainfall of up to 50% over the next 50–100 years. Efforts to predict the effects of changing climate, especially drought stress, on forest gas exchange are currently limited by uncertainty about the mechanism that controls stomatal closure in response to low soil moisture. At a through-fall exclusion experiment in Eastern Amazonia where water was experimentally excluded from the soil, we tested the hypothesis that plants are isohydric, that is, when water is scarce, the stomata act to prevent leaf water potential from dropping below a critical threshold level. We made diurnal measurements of leaf water potential ( Ψl), stomatal conductance ( gs), sap flow and stem water potential ( Ψstem) in the wet and dry seasons. We compared the data with the predictions of the soil–plant–atmosphere (SPA) model, which embeds the isohydric hypothesis within its stomatal conductance algorithm. The model inputs for meteorology, leaf area index (LAI), soil water potential and soil-to-leaf hydraulic resistance ( R) were altered between seasons in accordance with measured values. No optimization parameters were used to adjust the model. This ‘mechanistic’ model of stomatal function was able to explain the individual tree-level seasonal changes in water relations ( r2 = 0.85, 0.90 and 0.58 for Ψl, sap flow and gs, respectively). The model indicated that the measured increase in R was the dominant cause of restricted water use during the dry season, resulting in a modelled restriction of sap flow four times greater than that caused by reduced soil water potential. Higher resistance during the dry season resulted from an increase in below-ground resistance (including root and soil-to-root resistance) to water flow. [ABSTRACT FROM AUTHOR]

Background Despite the correlation between the use of protease inhibitors (PI) and adverse metabolic glycemic events, no prospective study has examined these parameters in pregnant women who use these drugs. Methods A prospective study was conducted on 57 pregnant women to investigate the effect of antiretroviral drugs (ARV) on the carbohydrate metabolism during pregnancy. The women were divided into three groups: ZDV Group, 20 HIV-1 infected women taking ZDV; TT Group, 25 patients on triple antiretroviral treatment (ZDV + 3TC + NFV); and Control Group, 12 pregnant women. Blood samples were obtained during the first visit for the determination of fasting plasma glycemia, when the patients were also submitted to a 75 g oral glucose test (OGTT-75g). These procedures were performed four times along pregnancy. Results The median values of the area under the glycemia curve (AUC) determined over a period of 120 min between the 33rd and 38th week were 11 685 mg/dL for the Control Group, 13 477 mg/dL for the ZDV Group, and 13 650 mg/dL for the TT Group ( p = 0.049). There was an increase in the AUC along pregnancy for all three groups studied, regardless of the treatment used, although this increase was significant only in the TT Group ( p = 0.001). The antiretroviral agents had no deleterious effects on prematurity, low birth weight, intrauterine growth restriction rates, or on Apgar score. Conclusion An association was detected between the use of PI and the development of carbohydrate intolerance during pregnancy. The antiretroviral agents had no deleterious effects on perinatal prognosis. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Alfama is one of the best known popular quarters of Lisboa, situated in the historical centre of the city, associated with the main symbols of Lisboa urban culture which range from festivals of the Popular Saints and! facto, to the alfacinha way of life: extrovert, astute, rowdy, cute, talkative, rapid and agile in their movements, sharp tongued in their speech. The population of Alfama is one of the most dense in Lisboa even though buildings are not normally higher then three storeys. This density has existed for some considerable time. In the context of global structures and processes of the Portuguese social formation, a set of social groups defines, to a large extent, its strategies through a game which is played on two boards: Alfama and the village. This allows people to inobilise survival and social recycling mechanisms, the forms of which are aspects of this double flight: flight from being fixed in the most degraded and subordinated conditions of peasant life; and from a new form of social fixation in the urban industrial working class.

Background: Despite the correlation between the use of protease inhibitors (PI) and adverse metabolic glycemic events, no prospective study has examined these parameters in pregnant women who use these drugs., Methods: A prospective study was conducted on 57 pregnant women to investigate the effect of antiretroviral drugs (ARV) on the carbohydrate metabolism during pregnancy. The women were divided into three groups: ZDV Group, 20 HIV-1 infected women taking ZDV; TT Group, 25 patients on triple antiretroviral treatment (ZDV + 3TC + NFV); and Control Group, 12 pregnant women. Blood samples were obtained during the first visit for the determination of fasting plasma glycemia, when the patients were also submitted to a 75 g oral glucose test (OGTT-75g). These procedures were performed four times along pregnancy., Results: The median values of the area under the glycemia curve (AUC) determined over a period of 120 min between the 33rd and 38th week were 11 685 mg/dL for the Control Group, 13 477 mg/dL for the ZDV Group, and 13 650 mg/dL for the TT Group (p = 0.049). There was an increase in the AUC along pregnancy for all three groups studied, regardless of the treatment used, although this increase was significant only in the TT Group (p = 0.001). The antiretroviral agents had no deleterious effects on prematurity, low birth weight, intrauterine growth restriction rates, or on Apgar score., Conclusion: An association was detected between the use of PI and the development of carbohydrate intolerance during pregnancy. The antiretroviral agents had no deleterious effects on perinatal prognosis., (Copyright (c) 2005 John Wiley & Sons, Ltd.)