A trade-off between growth and mortality rates characterizes tree species in closed canopy forests. This trade-off is maintained by inherent differences among species and spatial variation in light ...availability caused by canopy-opening disturbances. We evaluated conditions under which the trade-off is expressed and relationships with four key functional traits for 103 tree species from Barro Colorado Island, Panama. The trade-off is strongest for saplings for growth rates of the fastest growing individuals and mortality rates of the slowest growing individuals (
r
2
= 0.69), intermediate for saplings for average growth rates and overall mortality rates (
r
2
= 0.46), and much weaker for large trees (
r
2
≤ 0.10). This parallels likely levels of spatial variation in light availability, which is greatest for fast- vs. slow-growing saplings and least for large trees with foliage in the forest canopy. Inherent attributes of species contributing to the trade-off include abilities to disperse, acquire resources, grow rapidly, and tolerate shade and other stresses. There is growing interest in the possibility that functional traits might provide insight into such ecological differences and a growing consensus that seed mass (SM), leaf mass per area (LMA), wood density (WD), and maximum height (
H
max
) are key traits among forest trees. Seed mass, LMA, WD, and
H
max
are predicted to be small for light-demanding species with rapid growth and mortality and large for shade-tolerant species with slow growth and mortality. Six of these trait-demographic rate predictions were realized for saplings; however, with the exception of WD, the relationships were weak (
r
2
< 0.1 for three and
r
2
< 0.2 for five of the six remaining relationships). The four traits together explained 43-44% of interspecific variation in species positions on the growth-mortality trade-off; however, WD alone accounted for >80% of the explained variation and, after WD was included, LMA and
H
max
made insignificant contributions. Virtually the full range of values of SM, LMA, and
H
max
occurred at all positions on the growth-mortality trade-off. Although WD provides a promising start, a successful trait-based ecology of tropical forest trees will require consideration of additional traits.
Sentinel-node biopsy followed by lymphadenectomy for tumor-positive nodes improved disease-free survival among patients with intermediate-thickness melanomas (1.2 to 3.5 mm) and those with thick ...melanomas (>3.5 mm).
Regional node management in melanoma has remained controversial since Snow
1
recommended elective complete lymphadenectomy for all patients with melanoma, regardless of whether there was clinical evidence of regional nodal metastases. However, routine elective lymphadenectomy exposes all patients to procedure-related complications and cannot benefit the majority, who have no regional nodal metastases. Multiple randomized trials have suggested a benefit of routine lymphadenectomy in at least some groups of patients with melanoma.
2
–
6
Because of dissatisfaction with both elective lymphadenectomy and nodal observation, lymphatic mapping and sentinel-node biopsy were introduced for individualized management of regional lymph nodes.
6
–
9
Sentinel-node biopsy is a . . .
In response to the COVID-19 pandemic, many governments around the world now recommend, or require, that their citizens cover the lower half of their face in public. Consequently, many people now wear ...surgical face masks in public. We investigated whether surgical face masks affected the performance of human observers, and a state-of-the-art face recognition system, on tasks of perceptual face matching. Participants judged whether two simultaneously presented face photographs showed the same person or two different people. We superimposed images of surgical masks over the faces, creating three different mask conditions: control (no masks), mixed (one face wearing a mask), and masked (both faces wearing masks). We found that surgical face masks have a large detrimental effect on human face matching performance, and that the degree of impairment is the same regardless of whether one or both faces in each pair are masked. Surprisingly, this impairment is similar in size for both familiar and unfamiliar faces. When matching masked faces, human observers are biased to reject unfamiliar faces as “mismatches” and to accept familiar faces as “matches”. Finally, the face recognition system showed very high classification accuracy for control and masked stimuli, even though it had not been trained to recognise masked faces. However, accuracy fell markedly when one face was masked and the other was not. Our findings demonstrate that surgical face masks impair the ability of humans, and naïve face recognition systems, to perform perceptual face matching tasks. Identification decisions for masked faces should be treated with caution.
Attosecond science opened the door to observing nuclear and electronic dynamics in real time and has begun to expand beyond its traditional grounds. Among several spectroscopic techniques, X-ray ...transient absorption spectroscopy has become key in understanding matter on ultrafast time scales. In this review, we illustrate the capabilities of this unique tool through a number of iconic experiments. We outline how coherent broadband X-ray radiation, emitted in high-harmonic generation, can be used to follow dynamics in increasingly complex systems. Experiments performed in both molecules and solids are discussed at length, on time scales ranging from attoseconds to picoseconds, and in perturbative or strong-field excitation regimes. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether ...drought‐induced mortality rates differ among global biomes and whether functional traits influence the risk of drought‐induced mortality. To address these uncertainties, we performed a global meta‐analysis of 58 studies of drought‐induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global‐scale response, where mortality increased with drought severity log mortality (trees trees−1 year−1) increased 0.46 (95% CI = 0.2–0.7) with one SPEI unit drought intensity. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought‐induced tree mortality and suggest that mortality could become increasingly widespread in the future.
Abstract
Thanks to their unique optical properties Ge–Sb–S–Se–Te amorphous chalcogenide materials and compounds offer tremendous opportunities of applications, in particular in near and mid-infrared ...range. This spectral range is for instance of high interest for photonics or optical sensors. Using co-sputtering technique of chalcogenide compound targets in a 200 mm industrial deposition tool, we show how by modifying the amorphous structure of GeSb
w
S
x
Se
y
Te
z
chalcogenide thin films one can significantly tailor their linear and nonlinear optical properties. Modelling of spectroscopic ellipsometry data collected on the as-deposited chalcogenide thin films is used to evaluate their linear and nonlinear properties. Moreover, Raman and Fourier-transform infrared spectroscopies permitted to get a description of their amorphous structure. For the purpose of applications, their thermal stability upon annealing is also evaluated. We demonstrate that depending on the GeSb
w
S
x
Se
y
Te
z
film composition a trade-off between a high transparency in near- or mid-infrared ranges, strong nonlinearity and good thermal stability can be found in order to use such materials for applications compatible with the standard CMOS integration processes of microelectronics and photonics.
Quantitative immunoassay tests in clinical laboratories require trained technicians, take hours to complete with multiple steps, and the instruments used are generally immobile–patient samples have ...to be sent in to the labs for analysis. This prevents quantitative immunoassay tests to be performed outside laboratory settings. A portable, quantitative immunoassay device will be valuable in rural and resource-limited areas, where access to healthcare is scarce or far away. We have invented Eigen Diagnosis Platform (EDP), a portable quantitative immunoassay platform based on Giant Magnetoresistance (GMR) biosensor technology. The platform does not require a trained technician to operate, and only requires one-step user involvement. It displays quantitative results in less than 15min after sample insertion, and each test costs less than US$4. The GMR biosensor employed in EDP is capable of detecting multiple biomarkers in one test, enabling a wide array of immune diagnostics to be performed simultaneously. In this paper, we describe the design of EDP, and demonstrate its capability. Multiplexed assay of human immunoglobulin G and M (IgG and IgM) antibodies with EDP achieves sensitivities down to 0.07 and 0.33 nanomolar, respectively. The platform will allow lab testing to be performed in remote areas, and open up applications of immunoassay testing in other non-clinical settings, such as home, school, and office.
•Quantitative laboratory diagnostics requires trained technicians, multiple steps, and bulky instruments.•We have invented a portable quantitative immunoassay platform based on GMR technology with smartphone integration.•The platform can measure multiple protein biomarker concentrations within 15 minutes with only one-step user involvement.•Multiplex detection of human IgG and IgM antibodies with sensitivities of 0.07 and 0.33nM, respectively, was demonstrated.
Abstract
Gene and protein set enrichment analysis is a critical step in the analysis of data collected from omics experiments. Enrichr is a popular gene set enrichment analysis web-server search ...engine that contains hundreds of thousands of annotated gene sets. While Enrichr has been useful in providing enrichment analysis with many gene set libraries from different categories, integrating enrichment results across libraries and domains of knowledge can further hypothesis generation. To this end, Enrichr-KG is a knowledge graph database and a web-server application that combines selected gene set libraries from Enrichr for integrative enrichment analysis and visualization. The enrichment results are presented as subgraphs made of nodes and links that connect genes to their enriched terms. In addition, users of Enrichr-KG can add gene-gene links, as well as predicted genes to the subgraphs. This graphical representation of cross-library results with enriched and predicted genes can illuminate hidden associations between genes and annotated enriched terms from across datasets and resources. Enrichr-KG currently serves 26 gene set libraries from different categories that include transcription, pathways, ontologies, diseases/drugs, and cell types. To demonstrate the utility of Enrichr-KG we provide several case studies. Enrichr-KG is freely available at: https://maayanlab.cloud/enrichr-kg.
Graphical Abstract
Graphical Abstract
Aim: The knowledge of biodiversity facets such as species composition, distribution and ecological niche is fundamental for the construction of biogeographic hypotheses and conservation strategies. ...However, the knowledge on these facets is affected by major shortfalls, which are even more pronounced in the tropics. This study aims to evaluate the effect of sampling bias and variation in collection effort on Linnean, Wallacean and Hutchinsonian shortfalls and diversity measures as species richness, endemism and beta-diversity. Location: Brazil. Methods: We have built a database with over 1.5 million records of arthropods, vertebrates and angiosperms of Brazil, based on specimens deposited in scientific collections and on the taxonomic literature. We used null models to test the collection bias regarding the proximity to access routes. We also tested the influence of sampling effort on diversity measures by regression models. To investigate the Wallacean shortfall, we modelled the geographic distribution of over 4000 species and compared their observed distribution with models. To quantify the Hutchinsonian shortfall, we used environmental Euclidean distance of the records to identify regions with poorly sampled environmental conditions. To estimate the Linnean shortfall, we measured the similarity of species composition between regions close to and far from access routes. Results: We demonstrated that despite the differences in sampling effort, the strong collection bias affects all taxonomic groups equally, generating a pattern of spatially biased sampling effort. This collection pattern contributes greatly to the biodiversity knowledge shortfalls, which directly affects the knowledge on the distribution patterns of diversity. Main conclusions: The knowledge on species richness, species composition and endemism in the Brazilian biodiversity is strongly biased spatially. Despite differences in sampling effort for each taxonomic group, roadside bias affected them equally. Species composition similarity decreased with the distance from access routes, suggesting collection surveys at sites far from roads could increase the probability of sampling new geographic records or new species.
Estimates of evolutionary diversification rates - speciation and extinction - have been used extensively to explain global biodiversity patterns. Many studies have analyzed diversification rates ...derived from just two pieces of information: a clade's age and its extant species richness. This "age-richness rate" (ARR) estimator provides a convenient shortcut for comparative studies, but makes strong assumptions about the dynamics of species richness through time. Here we demonstrate that use of the ARR estimator in comparative studies is problematic on both theoretical and empirical grounds. We prove mathematically that ARR estimates are non-identifiable: there is no information in the data for a single clade that can distinguish a process with positive net diversification from one where net diversification is zero. Using paleontological time series, we demonstrate that the ARR estimator has no predictive ability for real datasets. These pathologies arise because the ARR inference procedure yields "point estimates" that have been computed under a saturated statistical model with zero degrees of freedom. Although ARR estimates remain useful in some contexts, they should be avoided for comparative studies of diversification and species richness.
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