Orbitally forced and internal changes in West African rainfall interannual-to-decadal variability for the last 6000 years.

Recent variability in West African monsoon rainfall (WAMR) has been shown to be influenced by multiple ocean-atmosphere modes, including the El Niño Southern Oscillation, Atlantic Multidecadal Oscillation and the Interdecadal Pacific Oscillation. How these modes will change in response to long term forcing is less well understood. Here we use four transient simulations driven by changes in orbital forcing and greenhouse gas concentrations over the past 6000 years to examine the relationship between West African monsoon rainfall multiscale variability and changes in the modes associated with this variability. All four models show a near linear decline in monsoon rainfall over the past 6000 years in response to the gradual weakening of the interhemispheric gradient in sea surface temperatures. The only indices that show a long-term trend are those associated with the strengthening of the El Niño Southern Oscillation from the mid-Holocene onwards. At the interannual-to-decadal timescale, WAMR variability is largely influenced by Pacific-Atlantic - Mediterranean Sea teleconnections in all simulations; the exact configurations are model sensitive. The WAMR interannual-to-decadal variability depicts marked multi-centennial oscillations, with La Niña/negative Pacific Decadal Oscillation and a weakening and/or poleward shift of subtropical high-pressure systems over the Atlantic favoring wet WAMR anomalies. The WAMR interannual-to-decadal variability also depicts an overall decreasing trend throughout the Holocene that is consistent among the simulations. This decreasing trend relates to changes in the North Atlantic and Gulf of Guinea Sea Surface Temperature variability. Supplementary Information: The online version contains supplementary material available at 10.1007/s00382-023-07023-y.

Novel naphthoquinone-1H-1,2,3-triazole hybrids: Design, synthesis and evaluation as inductors of ROS-mediated apoptosis in the MCF-7 cells.

The search for novel anticancer drugs is essential to expand treatment options, overcome drug resistance, reduce toxicity, promote innovation, and tackle the economic impact. The importance of these studies lies in their contribution to advancing cancer research and enhancing patient outcomes in the battle against cancer. Here, we developed new asymmetric hybrids containing two different naphthoquinones linked by a 1,2,3-1H-triazole nucleus, which are potential new drugs for cancer treatment. The antitumor activity of the novel compounds was tested using the breast cancer cell lines MCF-7 and MDA-MB-231, using the non-cancer cell line MCF10A as control. Our results showed that two out of twenty-two substances tested presented potential antitumor activity against the breast cancer cell lines. These potential drugs, named here 12g and 12h were effective in reducing cell viability and promoting cell death of the tumor cell lines, exhibiting minimal effects on the control cell line. The mechanism of action of the novel drugs was assessed revealing that both drugs increased reactive oxygen species production with consequent activation of the AMPK pathway. Therefore, we concluded that 12g and 12h are novel AMPK activators presenting selective antitumor effects.

Reduced global plant respiration due to the acclimation of leaf dark respiration coupled with photosynthesis.

Leaf dark respiration (Rd ) acclimates to environmental changes. However, the magnitude, controls and time scales of acclimation remain unclear and are inconsistently treated in ecosystem models. We hypothesized that Rd and Rubisco carboxylation capacity (Vcmax ) at 25°C (Rd,25 , Vcmax,25 ) are coordinated so that Rd,25 variations support Vcmax,25 at a level allowing full light use, with Vcmax,25 reflecting daytime conditions (for photosynthesis), and Rd,25 /Vcmax,25 reflecting night-time conditions (for starch degradation and sucrose export). We tested this hypothesis temporally using a 5-yr warming experiment, and spatially using an extensive field-measurement data set. We compared the results to three published alternatives: Rd,25 declines linearly with daily average prior temperature; Rd at average prior night temperatures tends towards a constant value; and Rd,25 /Vcmax,25 is constant. Our hypothesis accounted for more variation in observed Rd,25 over time (R2 = 0.74) and space (R2 = 0.68) than the alternatives. Night-time temperature dominated the seasonal time-course of Rd , with an apparent response time scale of c. 2 wk. Vcmax dominated the spatial patterns. Our acclimation hypothesis results in a smaller increase in global Rd in response to rising CO2 and warming than is projected by the two of three alternative hypotheses, and by current models.

Retrospective evaluation of the etiology and clinical characteristics of peripheral edema in dogs.

BACKGROUND: The prevalence and clinical characteristics of different etiologies of peripheral edema in dogs are unknown. HYPOTHESIS/OBJECTIVES: To determine the prevalence of different etiologies of peripheral edema, describe clinical characteristics that vary among etiologies, and report survival times. ANIMALS: Five hundred twenty-seven dogs with peripheral edema. METHODS: Retrospective medical record review. Differences in clinical variables among etiology groups were assessed by Kruskal-Wallis testing with post hoc pairwise Dunn's testing and Chi-square testing with Monte Carlo simulation. RESULTS: The most common etiologies of peripheral edema in dogs were vasculitis (n = 193, 37%), lymphatic/venous obstruction (LVO; 114, 22%), and hypoalbuminemia (94, 18%). Right-sided congestive heart failure (R-CHF) was uncommon (25, 5%). Edema was localized in 377 (72%) dogs and generalized in 142 (27%) dogs, and hypoalbuminemia was more likely to cause generalized edema compared to LVO or vasculitis (P < .0001). Concurrent abdominal effusion (155, 29%) was more common than pleural (77, 15%) or pericardial (12, 2%) effusion. Abdominal and pleural effusion occurred more commonly in dogs with hypoalbuminemia or R-CHF compared to LVO or vasculitis (P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Distribution of edema, concurrent cavitary effusions, and clinicopathological data can help predict the underlying etiology of peripheral edema in dogs.

Transmission of Mycobacterium tuberculosis to Healthcare Personnel Resulting From Contaminated Bone Graft Material, United States, June 2021-August 2022.

A nationwide tuberculosis outbreak linked to a viable bone allograft product contaminated with Mycobacterium tuberculosis was identified in June 2021. Our subsequent investigation identified 73 healthcare personnel with new latent tuberculosis infection following exposure to the contaminated product, product recipients, surgical instruments, or medical waste.

Optimality principles explaining divergent responses of alpine vegetation to environmental change.

Recent increases in vegetation greenness over much of the world reflect increasing CO2 globally and warming in cold areas. However, the strength of the response to both CO2 and warming in those areas appears to be declining for unclear reasons, contributing to large uncertainties in predicting how vegetation will respond to future global changes. Here, we investigated the changes of satellite-observed peak season absorbed photosynthetically active radiation (Fmax ) on the Tibetan Plateau between 1982 and 2016. Although climate trends are similar across the Plateau, we identified robust divergent responses (a greening of 0.31 ± 0.14% year-1 in drier regions and a browning of 0.12 ± 0.08% year-1 in wetter regions). Using an eco-evolutionary optimality (EEO) concept of plant acclimation/adaptation, we propose a parsimonious modelling framework that quantitatively explains these changes in terms of water and energy limitations. Our model captured the variations in Fmax with a correlation coefficient (r) of .76 and a root mean squared error of .12 and predicted the divergent trends of greening (0.32 ± 0.19% year-1 ) and browning (0.07 ± 0.06% year-1 ). We also predicted the observed reduced sensitivities of Fmax to precipitation and temperature. The model allows us to explain these changes: Enhanced growing season cumulative radiation has opposite effects on water use and energy uptake. Increased precipitation has an overwhelmingly positive effect in drier regions, whereas warming reduces Fmax in wetter regions by increasing the cost of building and maintaining leaf area. Rising CO2 stimulates vegetation growth by enhancing water-use efficiency, but its effect on photosynthesis saturates. The large decrease in the sensitivity of vegetation to climate reflects a shift from water to energy limitation. Our study demonstrates the potential of EEO approaches to reveal the mechanisms underlying recent trends in vegetation greenness and provides further insight into the response of alpine ecosystems to ongoing climate change.

The China plant trait database version 2.

Plant functional traits represent adaptive strategies to the environment, linked to biophysical and biogeochemical processes and ecosystem functioning. Compilations of trait data facilitate research in multiple fields from plant ecology through to land-surface modelling. Here we present version 2 of the China Plant Trait Database, which contains information on morphometric, physical, chemical, photosynthetic and hydraulic traits from 1529 unique species in 140 sites spanning a diversity of vegetation types. Version 2 has five improvements compared to the previous version: (1) new data from a 4-km elevation transect on the edge of Tibetan Plateau, including alpine vegetation types not sampled previously; (2) inclusion of traits related to hydraulic processes, including specific sapwood conductance, the area ratio of sapwood to leaf, wood density and turgor loss point; (3) inclusion of information on soil properties to complement the existing data on climate and vegetation (4) assessments and flagging the reliability of individual trait measurements; and (5) inclusion of standardized templates for systematical field sampling and measurements.

Molecular surveillance for large outbreaks of tuberculosis in the United States, 2014-2018.

OBJECTIVE: This study describes characteristics of large tuberculosis (TB) outbreaks in the United States detected using novel molecular surveillance methods during 2014-2016 and followed for 2 years through 2018. METHODS: We developed 4 genotype-based detection algorithms to identify large TB outbreaks of ≥10 cases related by recent transmission during a 3-year period. We used whole-genome sequencing and epidemiologic data to assess evidence of recent transmission among cases. RESULTS: There were 24 large outbreaks involving 518 cases; patients were primarily U.S.-born (85.1%) racial/ethnic minorities (84.1%). Compared with all other TB patients, patients associated with large outbreaks were more likely to report substance use, homelessness, and having been diagnosed while incarcerated. Most large outbreaks primarily occurred within residences among families and nonfamilial social contacts. A source case with a prolonged infectious period and difficulties in eliciting contacts were commonly reported contributors to transmission. CONCLUSION: Large outbreak surveillance can inform targeted interventions to decrease outbreak-associated TB morbidity.

Leaf morphological traits as adaptations to multiple climate gradients.

Leaf morphological traits vary systematically along climatic gradients. However, recent studies in plant functional ecology have mainly analysed quantitative traits, while numerical models of species distributions and vegetation function have focused on traits associated with resource acquisition; both ignore the wider functional significance of leaf morphology.A dataset comprising 22 leaf morphological traits for 662 woody species from 92 sites, representing all biomes present in China, was subjected to multivariate analysis in order to identify leading dimensions of trait covariation (correspondence analysis), quantify climatic and phylogenetic contributions (canonical correspondence analysis with variation partitioning) and characterise co-occurring trait syndromes (k-means clustering) and their climatic preferences.Three axes accounted for >20% of trait variation in both evergreen and deciduous species. Moisture index, precipitation seasonality and growing-season temperature explained 8%-10% of trait variation; family 15%-32%. Microphyll or larger, mid- to dark green leaves with drip tips in wetter climates contrasted with nanophyll or smaller glaucous leaves without drip tips in drier climates. Thick, entire leaves in less seasonal climates contrasted with thin, marginal dissected, aromatic and involute/revolute leaves in more seasonal climates. Thick, involute, hairy leaves in colder climates contrasted with thin leaves with marked surface structures (surface patterning) in warmer climates. Distinctive trait clusters were linked to the driest and most seasonal climates, for example the clustering of picophyll, fleshy and succulent leaves in the driest climates and leptophyll, linear, dissected, revolute or involute and aromatic leaves in regions with highly seasonal rainfall. Several trait clusters co-occurred in wetter climates, including clusters characterised by microphyll, moderately thick, patent and entire leaves or notophyll, waxy, dark green leaves. Synthesis. The plastic response of size, shape, colour and other leaf morphological traits to climate is muted, thus their apparent shift along climate gradients reflects plant adaptations to environment at a community level as determined by species replacement. Information on leaf morphological traits, widely available in floras, could be used to strengthen predictive models of species distribution and vegetation function.

A new method based on surface-sample pollen data for reconstructing palaeovegetation patterns.

Aim: Biomisation has been the most widely used technique to reconstruct past regional vegetation patterns because it does not require an extensive modern pollen dataset. However, it has well-known limitations including its dependence on expert judgement for the assignment of pollen taxa to plant functional types (PFTs) and PFTs to biomes. Here we present a new method that combines the strengths of biomisation with those of the alternative dissimilarity-based techniques. Location: The Eastern Mediterranean-Black Sea Caspian Corridor (EMBSeCBIO). Taxon: Plants. Methods: Modern pollen samples, assigned to biomes based on potential natural vegetation data, are used to characterize the within-biome means and standard deviations of the abundances of each taxon. These values are used to calculate a dissimilarity index between any pollen sample and every biome, and thus assign the sample to the most likely biome. We calculate a threshold value for each modern biome; fossil samples with scores below the threshold for all modern biomes are thus identified as non-analogue vegetation. We applied the new method to the EMBSeCBIO region to compare its performance with existing reconstructions. Results: The method captured changes in the importance of individual taxa along environmental gradients. The balanced accuracy obtained for the EMBSeCBIO region using the new method was better than obtained using biomisation (77% vs. 65%). When the method was applied to high-resolution fossil records, 70% of the entities showed more temporally stable biome assignments than obtained using biomisation. The technique also identified likely non-analogue assemblages in a synthetic modern dataset and in fossil records. Main conclusions: The new method yields more accurate and stable reconstructions of vegetation than biomisation. It requires an extensive modern pollen dataset, but is conceptually simple, and avoids subjective choices about taxon allocations to PFTs and PFTs to biomes.

Nationwide tuberculosis outbreak in the USA linked to a bone graft product: an outbreak report.

BACKGROUND: Mycobacterium tuberculosis transmission through solid organ transplantation has been well described, but transmission through transplanted tissues is rare. We investigated a tuberculosis outbreak in the USA linked to a bone graft product containing live cells derived from a single deceased donor. METHODS: In this outbreak report, we describe the management and severity of the outbreak and identify opportunities to improve tissue transplant safety in the USA. During early June, 2021, the US Centers for Disease Control and Prevention (CDC) worked with state and local health departments and health-care facilities to locate and sequester unused units from the recalled lot and notify, evaluate, and treat all identified product recipients. Investigators from CDC and the US Food and Drug Administration (FDA) reviewed donor screening and tissue processing. Unused product units from the recalled and other donor lots were tested for the presence of M tuberculosis using real-time PCR (rt PCR) assays and culture. M tuberculosis isolates from unused product and recipients were compared using phylogenetic analysis. FINDINGS: The tissue donor (a man aged 80 years) had unrecognised risk factors, symptoms, and signs consistent with tuberculosis. Bone was procured from the deceased donor and processed into 154 units of bone allograft product containing live cells, which were distributed to 37 hospitals and ambulatory surgical centres in 20 US states between March 1 and April 2, 2021. From March 3 to June 1, 2021, 136 (88%) units were implanted into 113 recipients aged 24-87 years in 18 states (some individuals received multiple units). The remaining 18 units (12%) were located and sequestered. 87 (77%) of 113 identified product recipients had microbiological or imaging evidence of tuberculosis disease. Eight product recipients died 8-99 days after product implantation (three deaths were attributed to tuberculosis after recognition of the outbreak). All 105 living recipients started treatment for tuberculosis disease at a median of 69 days (IQR 56-81) after product implantation. M tuberculosis was detected in all eight sequestered unused units tested from the recalled donor lot, but not in lots from other donors. M tuberculosis isolates from unused product and recipients were more than 99·99% genetically identical. INTERPRETATION: Donor-derived transmission of M tuberculosis via bone allograft resulted in substantial morbidity and mortality. All prospective tissue and organ donors should be routinely assessed for tuberculosis risk factors and clinical findings. When these are present, laboratory testing for M tuberculosis should be strongly considered. FUNDING: None.

Using Machine Learning Techniques and National Tuberculosis Surveillance Data to Predict Excess Growth in Genotyped Tuberculosis Clusters.

The early identification of clusters of persons with tuberculosis (TB) that will grow to become outbreaks creates an opportunity for intervention in preventing future TB cases. We used surveillance data (2009-2018) from the United States, statistically derived definitions of unexpected growth, and machine-learning techniques to predict which clusters of genotype-matched TB cases are most likely to continue accumulating cases above expected growth within a 1-year follow-up period. We developed a model to predict which clusters are likely to grow on a training and testing data set that was generalizable to a validation data set. Our model showed that characteristics of clusters were more important than the social, demographic, and clinical characteristics of the patients in those clusters. For instance, the time between cases before unexpected growth was identified as the most important of our predictors. A faster accumulation of cases increased the probability of excess growth being predicted during the follow-up period. We have demonstrated that combining the characteristics of clusters and cases with machine learning can add to existing tools to help prioritize which clusters may benefit most from public health interventions. For example, consideration of an entire cluster, not only an individual patient, may assist in interrupting ongoing transmission.

The timing, duration and magnitude of the 8.2 ka event in global speleothem records.

Abrupt events are a feature of many palaeoclimate records during the Holocene. The best example is the 8.2 ka event, which was triggered by a release of meltwater into the Labrador Sea and resulted in a weakening of poleward heat transport in the North Atlantic. We use an objective method to identify rapid climate events in globally distributed speleothem oxygen isotope records during the Holocene. We show that the 8.2 ka event can be identified in >70% of the speleothem records and is the most coherent signal of abrupt climate change during the last 12,000 years. The isotopic changes during the event are regionally homogenous: positive oxygen isotope anomalies are observed across Asia and negative anomalies are seen across Europe, the Mediterranean, South America and southern Africa. The magnitude of the isotopic excursions in Europe and Asia are statistically indistinguishable. There is no significant difference in the duration and timing of the 8.2 ka event between regions, or between the speleothem records and Greenland ice core records. Our study supports a rapid and global climate response to the 8.2 ka freshwater pulse into the North Atlantic, likely transmitted globally via atmospheric teleconnections.

Factores asociados al bloqueo de rama derecha en adultos mayores / Factors associated with right bundle branch block in older adults

RESUMEN Introducción: Existe poca literatura sobre la asociación entre el bloqueo de rama derecha y factores de riesgo como la hipertensión y la diabetes en pacientes de Latinoamérica y Perú. Objetivo: Determinar los factores asociados al bloqueo de rama derecha en adultos mayores. Métodos: Estudio transversal que incluyó 376 pacientes adultos mayores atendidos en el Hospital Almanzor Aguinaga Asenjo, Lambayeque-Perú. La variable dependiente fue la presencia de bloqueo de rama derecha y las variables independientes fueron edad, sexo, antecedente de hipertensión arterial y diabetes. Se estimaron razones de prevalencia e intervalos de confianza al 95 %. Resultados: De 376 pacientes, la mayoría eran varones (55,9 %), la edad media fue de 75,6 años, el 11,4 % tuvo antecedente de hipertensión y el 9 % era diabético. El 41 % tuvo diagnóstico de bloqueo de rama derecha. En la regresión múltiple; el sexo femenino (RP=1,53, IC 95 %: 1,21 - 1,95), antecedente de hipertensión (RP=1,55; IC 95 %: 1,21 - 2,00) y diabetes mellitus (RP=1,49, IC 95 %: 1,12 - 2,00) se asociaron de forma positiva a presentar bloqueo de rama derecha. El modelo anidado seleccionó las variables: sexo femenino (RP=1,54, IC 95 %: 1,21 - 1,96) y antecedente de hipertensión arterial (RP=1,61, IC 95 %: 1,25 - 2,08). Conclusión: El sexo femenino, antecedente de hipertensión arterial y de diabetes mellitus se asocian positivamente a presentar bloqueo de rama derecha.

ABSTRACT Introduction: There is little literature on the association between right bundle branch block and risk factors such as hypertension and diabetes in patients in Latin America and Peru. Objective: To determine the factors associated with right bundle branch block in older adults. Methods: Analytical cross-sectional study completed by 376 elderly patients treated at Almanzor Aguinaga Asenjo Hospital, Lambayeque-Peru. The dependent variable was the presence of right bundle branch block, and the independent variables were age, sex, history of hypertension, and diabetes. Prevalence ratios and 95 % confidence intervals were estimated. Results: Of 376 patients, the majority were male (55,9 %), the mean age was 75,6 years, 11,4 % had a history of hypertension and 9 % were diabetic; 41 % had a diagnosis of right bundle branch block. In simple regression, the frequency of right bundle branch block was 56 % (PR= 1,56; 95 % CI: 1,22-1,99), 65 % (PR=1,65; 95 % CI: 1,26 - 2,15) and 59 % (PR= 1,59; CI 95 %: 1,18 - 2,14) higher in women, hypertensive and diabetics; respectively. In the multiple regression; female sex (PR= 1,53; 95 % CI: 1,21 - 1,95), history of hypertension (PR= 1,55; 95 % CI: 1,21 - 2,00) and diabetes mellitus (PR= 1,49; 95 % CI: 1,12 - 2,00) were positively associated with right bundle branch block. The nested model selected the variables: female sex (PR= 1,54; 95 % CI: 1,21 - 1,96) and history of arterial hypertension (PR= 1,61; 95 % CI: 1,25 - 2,08). Conclusion: Female sex, history of arterial hypertension and diabetes mellitus were positively associated with presenting right bundle branch block in older adults.

Modelling and prediction of wind damage in forest ecosystems of the Sudety Mountains, SW Poland.

Windstorms are one of the most important disturbance factors in European forest ecosystems. An understanding of the major drivers causing observed changes in forests is essential to improve prediction models and as a basis for forest management. In the present study, we use machine learning techniques in combination with data sets on tree properties, bioclimatic and geomorphic conditions, to analyse the level of forest damage by windstorms in the Sudety Mountains over the period 2004-2010. We tested four scenarios under five classification model frameworks: logistic regression, random forest, support vector machines, neural networks, and gradient boosted modelling. Gradient boosted modelling and random forest have the best predictive power. Tree volume and age are the most important predictors of windstorm damage; climate and geomorphic variables are less important. Forest damage maps based on forest data from 2020 show lower probabilities of damage compared to the end of 20th and the beginning of 21st century.

Developing National Genotype-Independent Indicators for Recent Mycobacterium Tuberculosis Transmission Using Pediatric Cases-United States, 2011-2017.

INTRODUCTION: Pediatric tuberculosis (TB) cases are sentinel events for Mycobacterium tuberculosis transmission in communities because children, by definition, must have been infected relatively recently. However, these events are not consistently identified by genotype-dependent surveillance alerting methods because many pediatric TB cases are not culture-positive, a prerequisite for genotyping. METHODS: We developed 3 potential indicators of ongoing TB transmission based on identifying counties in the United States with relatively high pediatric (aged <15 years) TB incidence: (1) a case proportion indicator: an above-average proportion of pediatric TB cases among all TB cases; (2) a case rate indicator: an above-average pediatric TB case rate; and (3) a statistical model indicator: a statistical model based on a significant increase in pediatric TB cases from the previous 8-quarter moving average. RESULTS: Of the 249 US counties reporting ≥2 pediatric TB cases during 2009-2017, 240 and 249 counties were identified by the case proportion and case rate indicators, respectively. The statistical model indicator identified 40 counties with a significant increase in the number of pediatric TB cases. We compared results from the 3 indicators with an independently generated list of 91 likely transmission events involving ≥2 pediatric cases (ie, known TB outbreaks or case clusters with reported epidemiologic links). All counties with likely transmission events involving multiple pediatric cases were identified by ≥1 indicator; 23 were identified by all 3 indicators. PRACTICE IMPLICATIONS: This retrospective analysis demonstrates the feasibility of using routine TB surveillance data to identify counties where ongoing TB transmission might be occurring, even in the absence of available genotyping data.

Self-perceived competencies on evidence-based medicine in medical students and physicians registered in a virtual course: a cross-sectional study.

BACKGROUND: Evidence-based medicine (EBM) is defined as the integration of the best available evidence from scientific studies with clinical experience (and context) and with patients' values and preferences. The objective of the present study was to describe self-perceived EBM competencies in physicians and medical students enrolled in a massive virtual EBM course. METHODS: Analytical cross-sectional study. People interested in a free virtual EBM course fulfilled their data in a virtual form for their registration in September 2020. In this form, 22 competencies related to four dimensions of EBM were evaluated: asking a clinical question, search, analysis, and application; using a 5-option Likert scale. The resulting database was analyzed, selecting people who claimed to be physicians or medical students of 18 years or more. RESULTS: 1793 participants were included: 1130 medical students and 663 physicians; more than 80% lived in Peru. The frequency of participants who agreed or strongly agreed with feeling qualified in each competence ranged: from 39.2% to 57.8% for the competencies of the 'Asking a clinical question' dimension, from 39.2% to 56.1% for 'Search,' from 19.9% to 32.0% for 'Analysis,' and from 19.6% to 29.9% for 'Application.' Both in physicians and students, the lowest frequencies were for the competencies of interpretation of impact measures, graphs, and results of systematic reviews; as well as shared decision making and calculation of expected benefit. Physicians who graduated more recently scored better on competencies from search and analysis dimensions. CONCLUSION: Among physicians and medical students enrolled in the course, self-perception of competencies was lower in the dimensions of analysis and application. More recently graduated physicians seem to have a greater self-perception of their research and analysis skills, probably due to curricular updates.List of abbreviations: EBM: Evidence-based medicine; CIMBE, for its acronym in Spanish: International Course on Evidence-Based Medicine; SOCIMEP, for its acronym in Spanish: Peruvian Medical Student Scientific Society.

Coordination of plant hydraulic and photosynthetic traits: confronting optimality theory with field measurements.

Close coupling between water loss and carbon dioxide uptake requires coordination of plant hydraulics and photosynthesis. However, there is still limited information on the quantitative relationships between hydraulic and photosynthetic traits. We propose a basis for these relationships based on optimality theory, and test its predictions by analysis of measurements on 107 species from 11 sites, distributed along a nearly 3000-m elevation gradient. Hydraulic and leaf economic traits were less plastic, and more closely associated with phylogeny, than photosynthetic traits. The two sets of traits were linked by the sapwood to leaf area ratio (Huber value, vH ). The observed coordination between vH and sapwood hydraulic conductivity (KS ) and photosynthetic capacity (Vcmax ) conformed to the proposed quantitative theory. Substantial hydraulic diversity was related to the trade-off between KS and vH . Leaf drought tolerance (inferred from turgor loss point, -Ψtlp ) increased with wood density, but the trade-off between hydraulic efficiency (KS ) and -Ψtlp was weak. Plant trait effects on vH were dominated by variation in KS , while effects of environment were dominated by variation in temperature. This research unifies hydraulics, photosynthesis and the leaf economics spectrum in a common theoretical framework, and suggests a route towards the integration of photosynthesis and hydraulics in land-surface models.

Climate influence on the 2019 fires in Amazonia.

Amazonia experienced unusually devastating fires in August 2019, leading to huge regional and global environmental and economic losses. The increase in fires has been largely attributed to anthropogenic deforestation, but anomalous climate conditions could also have contributed. This study investigates the climate influence on Amazonia fires in August 2019 and underlying mechanisms, based on statistical correlation and multiple linear regression analyses of 2001-2019 satellite-based fire products and multiple observational or reanalyzed climate datasets. Positive fire anomalies in August 2019 were mainly located in southern Amazonia. These anomalies were mainly driven by low precipitation and relative humidity, which increased fuel dryness and contributed to 38.9 ± 9.5% of the 2019 anomaly in pyrogenic carbon emissions over the southern Amazonia. The dry conditions were associated with southerly wind anomalies over southern Amazonia that suppressed the climatological southward transport of water vapor originating from the Atlantic. The southerly wind anomalies were caused by the combination of a Gill-type cyclonic response to the warmer North Atlantic sea surface temperature (SST), and enhancement of the Walker and Hadley circulations over South America due to the colder SST in the eastern Pacific, and a mid-latitude wave train triggered by the warmer condition in the western Indian Ocean. Our study highlights, for the first time, the important role of Indian Ocean SST for fires in Amazonia. It also reveals how cold SST anomalies in the tropical eastern Pacific link the warm phase of the El Niño-Southern Oscillation (ENSO) in the preceding December-January to the dry-season fires in Amazonia. Our findings can develop theoretical basis of global tropical SST-based fire prediction, and have potential to improve prediction skill of extreme fires in Amazonia and thus to take steps to mitigate their impacts which is urgency given that dry conditions led to the extreme fires are becoming common in Amazonia.