180 research outputs found
Land Cover Classification of Complex Agroecosystems in the Non-Protected Highlands of the Galapagos Islands
The humid highlands of the Galapagos are the islands’ most biologically productive regions
and a key habitat for endemic animal and plant species. These areas are crucial for the region’s food
security and for the control of invasive plants, but little is known about the spatial distribution of
its land cover. We generated a baseline high-resolution land cover map of the agricultural zones
and their surrounding protected areas. We combined the high spatial resolution of PlanetScope
images with the high spectral resolution of Sentinel-2 images in an object-based classification using a
RandomForest algorithm. We used images collected with an unmanned aerial vehicle (UAV) to verify
and validate our classified map. Despite the astounding diversity and heterogeneity of the highland
landscape, our classification yielded useful results (overall Kappa: 0.7, R2: 0.69) and revealed that
across all four inhabited islands, invasive plants cover the largest fraction (28.5%) of the agricultural
area, followed by pastures (22.3%), native vegetation (18.6%), food crops (18.3%), and mixed forest
and pioneer plants (11.6%). Our results are consistent with historical trajectories of colonization and
abandonment of the highlands. The produced dataset is designed to suit the needs of practitioners of
both conservation and agriculture and aims to foster collaboration between the two areas
Diseño organizacional de una dependencia pública
The public administration in Mexico is constantly changing and competitive, so it seeks to establish goals that can be immediately visible externally by citizens, such as improvements in road infrastructure, street lighting and the creation of public spaces. Given this, the internal organizational problems that exist are left aside, which makes these problems persist from one administration after another; An example of this is in organizational design. This study seeks to find out if there is a relationship between the design and the organizational effectiveness of a public agency through a diagnostic study evaluated from the perspective of the workers.La administración pública en México es cambiante y competitiva, de modo que busca establecer metas que logren ser visibles de manera externa por los ciudadanos de manera inmediata, como las mejoras de la infraestructura vial, alumbramiento y la creación de espacios públicos. Ante esto, se dejan de lado los problemas organizacionales internos que existen, lo cual, hace que persistan estos problemas de una administración tras otra; un ejemplo de esto es en el diseño organizacional. Este estudio busca encontrar si existe relación entre el diseño y la efectividad organizacional de una dependencia pública a través de un estudio diagnóstico evaluado desde la perspectiva de los trabajadores
Usefulness of Serial Multiorgan Point-of-Care Ultrasound in Acute Heart Failure: Results from a Prospective Observational Cohort.
Background and Objectives: Acute heart failure (AHF) is a common disease and a cause
of high morbidity and mortality, constituting a major health problem. The main purpose of this
study was to determine the impact of multiorgan ultrasound in identifying pulmonary hypertension
(PH), a major prognostic factor in patients admitted due to AHF, and assess whether there are
significant changes in the venous excess ultrasonography (VE US) score or femoral vein Doppler at
discharge. Materials and Methods: Patients were evaluated with a standard protocol of lung ultrasound,
echocardiography, inferior vena cava (IVC) and hepatic, portal, intra-renal and femoral vein Doppler
flow patterns at admission and on the day of discharge. Results: Thirty patients were enrolled during
November 2021. The mean age was seventy-nine years (Standard Deviation–SD 13.4). Seven patients
(23.3%) had a worsening renal function during hospitalization. Regarding ultrasound findings,
VE US score was calculated at admission and at discharge, unexpectedly remaining unchanged or
even worsened (21 patients, 70.0%). The area under the curve for the lung score was 83.9% (p = 0.008),
obtaining a cutoff value of 10 that showed a sensitivity of 82.6% and a specificity of 71.4% in the
identification of intermediate and high PH. It was possible to monitor significant changes between
both exams on the lung score (16.5 vs. 9.3; p < 0.001), improvement in the hepatic vein Doppler
pattern (2.4 vs. 2.1; p = 0.002), improvement in portal vein Doppler pattern (1.7 vs. 1.4; p = 0.023),
without significant changes in the intra-renal vein Doppler pattern (1.70 vs. 1.57; p = 0.293), VE US
score (1.3 vs. 1.1; p = 0.501), femoral vein Doppler pattern (2.4 vs. 2.1; p = 0.161) and IVC collapsibility
(2.0 vs. 2.1; p = 0.420). Conclusions: Our study results suggest that performing serial multiorgan
Point-of-Care ultrasound can help us to better identify high and intermediate probability of PH
patients with AHF. Currently proposed multi-organ, venous Doppler scanning protocols, such as the
VE US score, should be further studied before expanding its use in AHF patients.post-print2977 K
First‐Ever Complete List of Amazonian Timber Tree Species
We compiled and presented a dataset (named “MADERA”) for all timber species reported in the Amazon region from all nine South American Amazonian countries. This work was based on official information from every country and on two substantial scientific references. Our final Amazonian timber species dataset contains 1,112 unique species records, which belong to 337 genera and 72 families from the lowland Amazonian rainforest, with associated information related to population, conservation (IUCN Red list categories), and trade status (ITTO/CITES) of each species. The authors of this research expect that the information provided will be useful to strengthen sustainable forest management and scientific research in the Amazonian region
Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.
Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited
Normothermic regional perfusion vs. super-rapid recovery in controlled donation after circulatory death liver transplantation
[Background & Aims] Although there is increasing interest in its use, definitive evidence demonstrating a benefit for postmortem normothermic regional perfusion (NRP) in controlled donation after circulatory death (cDCD) liver transplantation is lacking. The aim of this study was to compare results of cDCD liver transplants performed with postmortem NRP vs. super-rapid recovery (SRR), the current standard for cDCD.[Methods] This was an observational cohort study including all cDCD liver transplants performed in Spain between June 2012 and December 2016, with follow-up ending in December 2017. Each donor hospital determined whether organ recovery was performed using NRP or SRR. The propensity scores technique based on the inverse probability of treatment weighting (IPTW) was used to balance covariates across study groups; logistic and Cox regression models were used for binary and time-to-event outcomes.[Results] During the study period, there were 95 cDCD liver transplants performed with postmortem NRP and 117 with SRR. The median donor age was 56 years (interquartile range 45–65 years). After IPTW analysis, baseline covariates were balanced, with all absolute standardised differences <0.15. IPTW-adjusted risks were significantly improved among NRP livers for overall biliary complications (odds ratio 0.14; 95% CI 0.06–0.35, p <0.001), ischaemic type biliary lesions (odds ratio 0.11; 95% CI 0.02–0.57; p = 0.008), and graft loss (hazard ratio 0.39; 95% CI 0.20–0.78; p = 0.008).[Conclusions] The use of postmortem NRP in cDCD liver transplantation appears to reduce postoperative biliary complications, ischaemic type biliary lesions and graft loss, and allows for the transplantation of livers even from cDCD donors of advanced age.[Lay summary] This is a propensity-matched nationwide observational cohort study performed using livers recovered from donors undergoing cardiac arrest provoked by the intentional withdrawal of life support (controlled donation after circulatory death, cDCD). Approximately half of the livers were recovered after a period of postmortem in situ normothermic regional perfusion, which restored warm oxygenated blood to the abdominal organs, whereas the remainder were recovered after rapid preservation with a cold solution. The study results suggest that the use of postmortem normothermic regional perfusion helps reduce rates of post-transplant biliary complications and graft loss and allows for the successful transplantation of livers from older cDCD donors.Peer reviewe
Spread of a SARS-CoV-2 variant through Europe in the summer of 2020
[EN] Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3,4,5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes.S
Global patterns of vascular plant alpha diversity
Global patterns of regional (gamma) plant diversity are relatively well known, but whether these patterns hold for local communities, and the dependence on spatial grain, remain controversial. Using data on 170,272 georeferenced local plant assemblages, we created global maps of alpha diversity (local species richness) for vascular plants at three different spatial grains, for forests and non-forests. We show that alpha diversity is consistently high across grains in some regions (for example, Andean-Amazonian foothills), but regional 'scaling anomalies' (deviations from the positive correlation) exist elsewhere, particularly in Eurasian temperate forests with disproportionally higher fine-grained richness and many African tropical forests with disproportionally higher coarse-grained richness. The influence of different climatic, topographic and biogeographical variables on alpha diversity also varies across grains. Our multi-grain maps return a nuanced understanding of vascular plant biodiversity patterns that complements classic maps of biodiversity hotspots and will improve predictions of global change effects on biodiversity
Local hydrological conditions influence tree diversity and composition across the Amazon basin
Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
- …