Institution
Central University of Ecuador
Education•Quito, Ecuador•
About: Central University of Ecuador is a education organization based out in Quito, Ecuador. It is known for research contribution in the topics: Population & Cutaneous leishmaniasis. The organization has 2220 authors who have published 1910 publications receiving 15052 citations.
Papers published on a yearly basis
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Naturalis1, Utrecht University2, Duke University3, Institut de recherche pour le développement4, Institut national de la recherche agronomique5, Museu Paraense Emílio Goeldi6, University of California, Berkeley7, University of Leeds8, Empresa Brasileira de Pesquisa Agropecuária9, National Institute of Amazonian Research10, National University of Saint Anthony the Abbot in Cuzco11, University of Exeter12, World Wide Fund for Nature13, Universidad Autónoma Gabriel René Moreno14, Norwegian University of Life Sciences15, Max Planck Society16, James Cook University17, Universidade do Estado de Mato Grosso18, University of Amsterdam19, Silver Spring Networks20, State University of Campinas21, University of Edinburgh22, University of Los Andes23, Smithsonian Conservation Biology Institute24, National University of Colombia25, University of East Anglia26, Central University of Ecuador27, Centre national de la recherche scientifique28, Humboldt State University29, New York Botanical Garden30, Universidade Federal do Acre31, Paul Sabatier University32, Missouri Botanical Garden33, Amazon.com34, University of Texas at Austin35, University of Florida36, Venezuelan Institute for Scientific Research37, Environmental Change Institute38, Federal Rural University of Amazonia39, University of São Paulo40, State University of Norte Fluminense41, Smithsonian Tropical Research Institute42, University of Wisconsin–Milwaukee43, Northern Arizona University44, Aarhus University45, Tropenbos International46, University of Kent47, Royal Botanic Gardens48, Universidad Nacional de la Amazonía Peruana49, University of Missouri–St. Louis50, Fairchild Tropical Botanic Garden51, Florida International University52, Wake Forest University53
TL;DR: The finding that Amazonia is dominated by just 227 tree species implies that most biogeochemical cycling in the world’s largest tropical forest is performed by a tiny sliver of its diversity.
Abstract: The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree community.
963 citations
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TL;DR: In this article, the distribution and abundance of tropical tree species in lowland terra firme forests in western Amazonia is investigated. But the results show that most species show landscape-scale densities of <1 individual/ha, and most trees in both forests belong to a small set of ubiquitous common species.
Abstract: Amazonian forests are the largest and most diverse in the tropics, and much of the mystery surrounding their ecology can be traced to attempts to understand them through tiny local inventories. In this paper we bring together a large number of such inventories scattered across immense areas of western Amazonia in order to address simple questions about the distribution and abundance of tropical tree species in lowland terra firme forests there. The goal is to describe patterns of commonness and rarity at local (1 ha), landscape (∼104 km2), and regional (>106 km2) scales, and to fuse the results into a more complete picture of how tropical tree communities are structured. We present estimates of landscape-scale densities for ∼1400 taxa, based on data from tree plots scattered over large tracts of terra firme forest in eastern Ecuador and southeastern Peru. A database of morphological, ecological, and other traits of >1000 of these species compiled from the taxonomic literature is then used to explore how species that are common in the inventories differ from species that are rare.
Although most species show landscape-scale densities of <1 individual/ha, most trees in both forests belong to a small set of ubiquitous common species. These common species combine high frequency with high local abundance, forming predictable oligarchies that dominate several thousand square kilometers of forest at each site.
The common species comprising these oligarchies are a nonrandom subset of the two floras. At both sites a disproportionate number of common species are concentrated in the families Arecaceae, Moraceae, Myristicaceae, and Violaceae, and large-statured tree species are more likely to be common than small ones. Nearly a third of the 150 most common tree species in the Ecuadorean forest are also found among the 150 most common tree species in the Peruvian forest. For the 254 tree species shared by the two data sets, abundance in Ecuador is positively and significantly correlated with abundance ∼1400 km away in Peru.
These findings challenge popular depictions of Amazonian vegetation as a small-scale mosaic of unpredictable composition and structure. Instead, they provide additional evidence that tropical tree communities are not qualitatively different from their temperate counterparts, where a few common species concentrated in a few higher taxa can dominate immense areas of forest. We hypothesize that most Amazonian forests are dominated at large scales by oligarchies similar in nature to the ones observed in Ecuador and Peru, and we argue that the patterns are more indicative of regulation of relative abundances by ecological factors than of nonequilibrium chance-based dynamics. The paper concludes with a discussion of the practical applications of predictable oligarchies over large areas of unexplored forest.
566 citations
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TL;DR: It is shown that non-fragmented Amazon forests are experiencing a concerted increase in the density, basal area and mean size of woody climbing plants (lianas), which implies that the tropical terrestrial carbon sink may shut down sooner than current models suggest.
Abstract: Ecological orthodoxy suggests that old-growth forests should be close to dynamic equilibrium, but this view has been challenged by recent findings that neotropical forests are accumulating carbon and biomass, possibly in response to the increasing atmospheric concentrations of carbon dioxide. However, it is unclear whether the recent increase in tree biomass has been accompanied by a shift in community composition. Such changes could reduce or enhance the carbon storage potential of old-growth forests in the long term. Here we show that non-fragmented Amazon forests are experiencing a concerted increase in the density, basal area and mean size of woody climbing plants (lianas). Over the last two decades of the twentieth century the dominance of large lianas relative to trees has increased by 1.7-4.6% a year. Lianas enhance tree mortality and suppress tree growth, so their rapid increase implies that the tropical terrestrial carbon sink may shut down sooner than current models suggest. Predictions of future tropical carbon fluxes will need to account for the changing composition and dynamics of supposedly undisturbed forests.
531 citations
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Pontifical Catholic University of Chile1, ICESI University2, University of São Paulo3, National University of La Plata4, University of the Republic5, American Society of Safety Engineers6, Universidade Federal do Rio Grande do Sul7, University of Paris-Sud8, Humanitas University9, Central University of Ecuador10
TL;DR: Among patients with septic shock, a resuscitation strategy targeting normalization of capillary refill time, compared with a strategy targeting serum lactate levels, did not reduce all-cause 28-day mortality.
Abstract: Importance Abnormal peripheral perfusion after septic shock resuscitation has been associated with organ dysfunction and mortality. The potential role of the clinical assessment of peripheral perfusion as a target during resuscitation in early septic shock has not been established. Objective To determine if a peripheral perfusion–targeted resuscitation during early septic shock in adults is more effective than a lactate level–targeted resuscitation for reducing mortality. Design, Setting, and Participants Multicenter, randomized trial conducted at 28 intensive care units in 5 countries. Four-hundred twenty-four patients with septic shock were included between March 2017 and March 2018. The last date of follow-up was June 12, 2018. Interventions Patients were randomized to a step-by-step resuscitation protocol aimed at either normalizing capillary refill time (n = 212) or normalizing or decreasing lactate levels at rates greater than 20% per 2 hours (n = 212), during an 8-hour intervention period. Main Outcomes and Measures The primary outcome was all-cause mortality at 28 days. Secondary outcomes were organ dysfunction at 72 hours after randomization, as assessed by Sequential Organ Failure Assessment (SOFA) score (range, 0 [best] to 24 [worst]); death within 90 days; mechanical ventilation–, renal replacement therapy–, and vasopressor-free days within 28 days; intensive care unit and hospital length of stay. Results Among 424 patients randomized (mean age, 63 years; 226 [53%] women), 416 (98%) completed the trial. By day 28, 74 patients (34.9%) in the peripheral perfusion group and 92 patients (43.4%) in the lactate group had died (hazard ratio, 0.75 [95% CI, 0.55 to 1.02];P = .06; risk difference, −8.5% [95% CI, −18.2% to 1.2%]). Peripheral perfusion–targeted resuscitation was associated with less organ dysfunction at 72 hours (mean SOFA score, 5.6 [SD, 4.3] vs 6.6 [SD, 4.7]; mean difference, −1.00 [95% CI, −1.97 to −0.02];P = .045). There were no significant differences in the other 6 secondary outcomes. No protocol-related serious adverse reactions were confirmed. Conclusions and Relevance Among patients with septic shock, a resuscitation strategy targeting normalization of capillary refill time, compared with a strategy targeting serum lactate levels, did not reduce all-cause 28-day mortality. Trial Registration ClinicalTrials.gov Identifier:NCT03078712
432 citations
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Daniel S. Karp1, Rebecca Chaplin-Kramer2, Timothy D. Meehan3, Emily A. Martin4 +153 more•Institutions (81)
TL;DR: Analysis of the largest pest-control database of its kind shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others.
Abstract: The idea that noncrop habitat enhances pest control and represents a win-win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win-win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.
398 citations
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Showing all 2257 results
Name | H-index | Papers | Citations |
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Hemmo A. Drexhage | 66 | 317 | 16299 |
Patricio Lopez-Jaramillo | 66 | 357 | 24077 |
David A. Neill | 44 | 108 | 12071 |
Rutgerd Boelens | 39 | 187 | 4578 |
Manuel O. Landázuri | 37 | 62 | 4615 |
Virginia Motilva | 35 | 103 | 3897 |
Vincenzo Torretta | 31 | 194 | 3379 |
Yoshihisa Hashiguchi | 31 | 156 | 3132 |
Giovanni Vidari | 29 | 248 | 3878 |
Juan Carlos Navarro | 26 | 109 | 2172 |
Isabel Hernández | 25 | 136 | 2359 |
Tatsuyuki Mimori | 24 | 67 | 1858 |
César Paz-y-Miño | 24 | 134 | 1600 |
Rodrigo X. Armijos | 23 | 42 | 1535 |
Manuel Calvopiña | 22 | 32 | 1301 |