The fate of tropical forests under future climate change is dependent on the capacity of their trees to adjust to drier conditions. The capacity of trees to withstand drought is likely to be ...determined by traits associated with their hydraulic systems. However, data on whether tropical trees can adjust hydraulic traits when experiencing drought remain rare. We measured plant hydraulic traits (e.g. hydraulic conductivity and embolism resistance) and plant hydraulic system status (e.g. leaf water potential, native embolism and safety margin) on >150 trees from 12 genera (36 species) and spanning a stem size range from 14 to 68 cm diameter at breast height at the world's only long‐running tropical forest drought experiment. Hydraulic traits showed no adjustment following 15 years of experimentally imposed moisture deficit. This failure to adjust resulted in these drought‐stressed trees experiencing significantly lower leaf water potentials, and higher, but variable, levels of native embolism in the branches. This result suggests that hydraulic damage caused by elevated levels of embolism is likely to be one of the key drivers of drought‐induced mortality following long‐term soil moisture deficit. We demonstrate that some hydraulic traits changed with tree size, however, the direction and magnitude of the change was controlled by taxonomic identity. Our results suggest that Amazonian trees, both small and large, have limited capacity to acclimate their hydraulic systems to future droughts, potentially making them more at risk of drought‐induced mortality.
The fate of tropical forests under future climate change is dependent on the capacity of their trees to adjust to drier conditions. Following 15 years of experimentally imposed moisture deficit, Amazon trees showed no adjustment in their hydraulic traits to moisture deficit. This failure to adjust resulted in these drought‐stressed trees experiencing significantly reduced water potential and increased hydraulic failure. Both, small and large trees equally, could not adapt to moisture deficit. Our results suggest Amazon trees have a limited capacity to adjust to future droughts.
Drought threatens tropical rainforests over seasonal to decadal timescales, but the drivers of tree mortality following drought remain poorly understood. It has been suggested that reduced ...availability of non-structural carbohydrates (NSC) critically increases mortality risk through insufficient carbon supply to metabolism ('carbon starvation'). However, little is known about how NSC stores are affected by drought, especially over the long term, and whether they are more important than hydraulic processes in determining drought-induced mortality. Using data from the world's longest-running experimental drought study in tropical rainforest (in the Brazilian Amazon), we test whether carbon starvation or deterioration of the water-conducting pathways from soil to leaf trigger tree mortality. Biomass loss from mortality in the experimentally droughted forest increased substantially after >10 years of reduced soil moisture availability. The mortality signal was dominated by the death of large trees, which were at a much greater risk of hydraulic deterioration than smaller trees. However, we find no evidence that the droughted trees suffered carbon starvation, as their NSC concentrations were similar to those of non-droughted trees, and growth rates did not decline in either living or dying trees. Our results indicate that hydraulics, rather than carbon starvation, triggers tree death from drought in tropical rainforest.
The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian
species mosquitos highlights a need to monitor the risk of reestablishment of urban ...YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.
Determining climate change feedbacks from tropical rainforests requires an understanding of how carbon gain through photosynthesis and loss through respiration will be altered. One of the key changes ...that tropical rainforests may experience under future climate change scenarios is reduced soil moisture availability. In this study we examine if and how both leaf photosynthesis and leaf dark respiration acclimate following more than 12 years of experimental soil moisture deficit, via a through‐fall exclusion experiment (TFE) in an eastern Amazonian rainforest. We find that experimentally drought‐stressed trees and taxa maintain the same maximum leaf photosynthetic capacity as trees in corresponding control forest, independent of their susceptibility to drought‐induced mortality. We hypothesize that photosynthetic capacity is maintained across all treatments and taxa to take advantage of short‐lived periods of high moisture availability, when stomatal conductance (gₛ) and photosynthesis can increase rapidly, potentially compensating for reduced assimilate supply at other times. Average leaf dark respiration (Rd) was elevated in the TFE‐treated forest trees relative to the control by 28.2 ± 2.8% (mean ± one standard error). This mean Rd value was dominated by a 48.5 ± 3.6% increase in the Rd of drought‐sensitive taxa, and likely reflects the need for additional metabolic support required for stress‐related repair, and hydraulic or osmotic maintenance processes. Following soil moisture deficit that is maintained for several years, our data suggest that changes in respiration drive greater shifts in the canopy carbon balance, than changes in photosynthetic capacity.
ABSTRACT
The Southern Photometric Local Universe Survey (S-PLUS) is an ongoing survey of ∼9300 deg2 in the southern sky in a 12-band photometric system. This paper presents the second data release ...(DR2) of S-PLUS, consisting of 514 tiles covering an area of 950 deg2. The data has been fully calibrated using a new photometric calibration technique suitable for the new generation of wide-field multifilter surveys. This technique consists of a χ2 minimization to fit synthetic stellar templates to already calibrated data from other surveys, eliminating the need for standard stars and reducing the survey duration by ∼15 per cent. We compare the template-predicted and S-PLUS instrumental magnitudes to derive the photometric zero-points (ZPs). We show that these ZPs can be further refined by fitting the stellar templates to the 12 S-PLUS magnitudes, which better constrain the models by adding the narrow-band information. We use the STRIPE82 region to estimate ZP errors, which are ≲ 10 mmags for filters J0410, J0430, g, J0515, r, J0660, i, J0861 and z; ≲ 15 mmags for filter J0378; and ≲ 25 mmags for filters u and J0395. We describe the complete data flow of the S-PLUS/DR2 from observations to the final catalogues and present a brief characterization of the data. We show that, for a minimum signal-to-noise threshold of 5, the photometric depths of the DR2 range from 19.1 to 20.5 mag (measured in Petrosian apertures), depending on the filter. The S-PLUS DR2 can be accessed from the website: https://splus.cloud.
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•Forensic analysis of artwork.•Pigment analysis by FTIR.•Pigment analysis by XRF.•Analysis of artworks by MA-XRF.•Scientific analysis of analytical data.
This work studied suspicious ...and authentic artworks by Brazilian painters Ivan Serpa, Ismael Nery, and Iberê Camargo by XRF, FTIR, OM, and MA-XRF techniques. The studies made it possible to verify that all suspicious artworks are counterfeit artifacts. The analyses were conducted in situ, and different approaches were applied for data treatment. For example, principal component analysis and spectral deconvolution were performed on the XRF data. From these methods, it was possible to verify that the suspect artworks by Ivan Serpa and Iberê Camargo have different materiality than the authentic paintings. Additionally, MA-XRF images did not reveal the presence of a polychrome preparation layer in the suspicious paintings by Ivan Serpa. The suspect artworks from Ismael Nery exhibited a Ca-K/Ti-K ratio that indicates they were created on a low-quality paper support, which is not suitable for paintings. The differences in materials used in the suspicious and authentic artworks are further supported by the FTIR and OM results. In addition to the physicochemical analysis, the paintings were studies graphotechnical examinations, financial evaluations, and artistic analyses that demonstrated they were counterfeit artifacts. The results of the analysis demonstrate how physicochemical techniques can contribute to the forensic investigation of paintings. However, this work highlights the importance of applying distinct treatments to the XRF data in order to accentuate the differences between the suspect and authentic artworks.
Objective
To evaluate the maternal–fetal outcomes of CAB-induced pregnancies in patients with prolactinoma in a large cohort.
Methods
The prevalence of tumor growth, miscarriage, preterm, low birth ...weight, congenital malformations and impairment in neuropsychological development in children among women treated with CAB were assessed in a Brazilian multicentre retrospective observational study,
Results
We included 194 women with a mean age of 31 (17–45) years, 43.6% presenting microadenomas and 56.4% macroadenomas, at prolactinoma diagnosis. In 233 pregnancies, CAB was withdrawn in 89%, after pregnancy confirmation. Symptoms related to tumor growth occurred in 25 cases, more frequently in macroadenomas. The overall miscarriage rate was 11%, although higher in the subgroup of patients with CAB maintainance after pregnancy confirmation (38% vs. 7.5%). Amongst the live-birth deliveries, preterm occurred in 12%, low birth weight in 6% and congenital malformations in 4.3%. Neuropsychological development impairment was reported in 7% of cases.
Conclusions
Our findings confirm previous results of safety in maternal and fetal outcomes in CAB-induced pregnancies; nevertheless, CAB maintenance after pregnancy confirmation was associated with higher miscarriage rate; result that must be further confirmed.
Summary
Plant traits are increasingly being used to improve prediction of plant function, including plant demography. However, the capability of plant traits to predict demographic rates remains ...uncertain, particularly in the context of trees experiencing a changing climate.
Here we present data combining 17 plant traits associated with plant structure, metabolism and hydraulic status, with measurements of long‐term mean, maximum and relative growth rates for 176 trees from the world’s longest running tropical forest drought experiment.
We demonstrate that plant traits can predict mean annual tree growth rates with moderate explanatory power. However, only combinations of traits associated more directly with plant functional processes, rather than more commonly employed traits like wood density or leaf mass per area, yield the power to predict growth. Critically, we observe a shift from growth being controlled by traits related to carbon cycling (assimilation and respiration) in well‐watered trees, to traits relating to plant hydraulic stress in drought‐stressed trees.
We also demonstrate that even with a very comprehensive set of plant traits and growth data on large numbers of tropical trees, considerable uncertainty remains in directly interpreting the mechanisms through which traits influence performance in tropical forests.
Living cells are constantly exchanging momentum with their surroundings. So far, there is no consensus regarding how cells respond to such external stimuli, although it reveals much about their ...internal structures, motility as well as the emergence of disorders. Here, we report that twelve cell lines, ranging from healthy fibroblasts to cancer cells, hold a ubiquitous double power-law viscoelastic relaxation compatible with the fractional Kelvin-Voigt viscoelastic model. Atomic Force Microscopy measurements in time domain were employed to determine the mechanical parameters, namely, the fast and slow relaxation exponents, the crossover timescale between power law regimes, and the cell stiffness. These cell-dependent quantities show strong correlation with their collective migration and invasiveness properties. Beyond that, the crossover timescale sets the fastest timescale for cells to perform their biological functions.
Visceral leishmaniasis (VL) is a disease caused by Leishmania infantum, which is transmitted by phlebotomine sandflies. Dogs are the main urban reservoir of this parasite and the disease presents ...similar characteristics in both humans and dogs. In this paper, we investigated the potential pathways involved in plasma cell replacement of normal cell populations in the spleen, with respect to disease severity in dogs from an endemic area for visceral leishmaniasis. To this end, canine spleen samples were grouped into three categories: TYPE1SC- (non-infected dogs or without active infection with organized white pulp), TYPE1SC+ (infected dogs with organized white pulp) or TYPE3SC+ (infected animals with disorganized white pulp). We analyzed the distribution of different plasma cell isotypes (IgA, IgG and IgM) in the spleen. The expression of cytokines and chemokines involved in plasma cell homing and survival were assessed by real time RT-PCR. Polyclonal B cell activation and hypergammaglobulinemia were also evaluated. The proportion of animals with moderate or intense plasmacytosis was higher in the TYPE3SC+ group than in the other groups (Fisher test, P<0.05). This was mainly due to a higher density of IgG+ plasma cells in the red pulp of this group. The albumin/globulin ratio was lower in the TYPE3SC+ animals than in the TYPE1SC- or TYPE1SC+ animals, which evidences VL-associated dysproteinemia. Interestingly, TYPE3SC+ animals showed increased expression of the BAFF and APRIL cytokines, as well as chemokine CXCL12. Aberrant expression of BAFF, APRIL and CXCL12, together with amplified extrafollicular B cell activation, lead to plasma cell homing and the extended survival of these cells in the splenic red pulp compartment. These changes in the distribution of immunocompetent cells in the spleen may contribute to the progression of VL, and impair the spleen's ability to protect against blood borne pathogens.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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