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Temporal scale in animal communities is often associated with seasonality, despite the large variation in species activity during a diel cycle. A gap thus remains in understanding the dynamics of short-term activity in animal communities. Here we assessed calling activity of tropical anurans and addressed how species composition varied during night activity in assemblages along gradients of local and landscape environmental heterogeneity. We investigated 39 anuran assemblages in the Pantanal wetlands (Brazil) with passive acoustic monitoring during the peak of one breeding season, and first determined changes in species composition between night periods (early, mid and late) using two temporal resolutions (1- and 3-hr intervals). Then, we addressed the role of habitat structure (local and landscape heterogeneity variables from field-based and remote sensing metrics) and ecological context (species richness and phylogenetic relatedness) in determining changes in species composition (a) between night periods and (b) across days. Nocturnal calling activity of anuran assemblages varied more within the 1-hr resolution than the 3-hr resolution. Differences in species composition between early- and late-night periods were related to local habitat structure and phylogenetic relatedness, while a low variation in compositional changes across days was associated with low-heterogeneous landscapes. None of these relationships were observed using the coarser temporal resolution (3 hr). Our findings on the variation of calling activity in tropical anuran assemblages suggest potential trade-offs mediated by fine-temporal partitioning. Local and landscape heterogeneity may provide conditions for spatial partitioning, while the relatedness among co-signalling species provides cues on the ecological overlap of species with similar requirements. These relationships suggest a role of niche dimensional complementarity on the structuring of these anuran assemblages over fine-temporal scales. We argue that fine-temporal differences between species in breeding activity can influence the outcome of species interaction and thus, addressing temporal scaling issues can improve our understanding of the dynamics of animal communities.
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Anuros , Ecosistema , Animales , Biodiversidad , Brasil , Filogenia , HumedalesRESUMEN
Olefin double-bond functionalization has been established as an excellent strategy for the construction of elaborate molecules. In particular, the hydroalkylation of olefins represents a straightforward strategy for the synthesis of new C(sp3)-C(sp3) bonds, with concomitant formation of challenging quaternary carbon centers. In the last 20 years, numerous hydroalkylation methodologies have emerged that have explored the diverse reactivity patterns of the olefin double bond. This review presents examples of olefins acting as electrophilic partners when coordinated with electrophilic transition-metal complexes or, in more recent approaches, when used as precursors of nucleophilic radical species in metal hydride hydrogen atom transfer reactions. This unique reactivity, combined with the wide availability of olefins as starting materials and the success reported in the construction of all-carbon C(sp3) quaternary centers, makes hydroalkylation reactions an ideal platform for the synthesis of molecules with increased molecular complexity.
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Sequential one-pot 2-iodoxybenzoic acid (IBX) oxidation of Morita-Baylis-Hillman (MBH) adducts followed by catalyst-free indolizine conjugate addition was developed. The wide scopes of MBH adducts and indolizines were investigated, and densely functionalized adducts were obtained in yields of up to 94%. The conjugate addition step occurred in less than a minute at room temperature with total regioselectivity toward indolizine C3 carbon. Less nucleophilic C1 carbon was also alkylated when C3-substituted indolizines were employed as the substrate.
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Leptogenys is the most diverse genus of the ant subfamily Ponerinae and is widely distributed across the world's tropical and subtropical regions. More than 40 species are known from the Oriental realm displaying a wide range of ecologies, although their life history traits remain poorly understood, and new species are frequently discovered. Here, a faunal review of the genus from Hong Kong SAR, southern China is provided. A total of nine species are recorded, with one new species, Leptogenysgrohli Hamer, Lee & Guénard, sp. nov. described. Ecological and biogeographic information, including new information on reproductive modes for two species are provided with the ergatoids of L.binghamii Forel, 1900 and L.rufidaZhou et al., 2012 described. Additional records for five of these species within the neighbouring province of Guangdong are also provided. Finally, an illustrated key to species known from Hong Kong is presented, as well as notes on each species' distribution, ecology, and behaviour. An updated provincial distributional checklist of the Leptogenys species of Mainland China and Taiwan is also supplied.
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Macrophyte net primary productivity (NPP) is a significant but understudied component of the carbon budget in large Amazonian floodplains. Annual NPP is determined by the interaction between stem elongation (vertical growth) and plant cover changes (horizontal expansion), each affected differently by flood duration and amplitude. Therefore, hydrological changes as predicted for the Amazon basin could result in significant changes in annual macrophyte NPP. This study investigates the responses of macrophyte horizontal expansion and vertical growth to flooding variability, and its possible effects on the contribution of macrophytes to the carbon budget of Amazonian floodplains. Monthly macrophyte cover was estimated using satellite imagery for the 2003-2004 and 2004-2005 hydrological years, and biomass was measured in situ between 2003 and 2004. Regression models between macrophyte variables and river-stage data were used to build a semiempirical model of macrophyte NPP as a function of water level. Historical river-stage records (1970-2011) were used to simulate variations in NPP, as a function of annual flooding. Vertical growth varied by a factor of ca. 2 over the simulated years, whereas minimum and maximum annual cover varied by ca. 3.5 and 1.5, respectively. Results suggest that these processes act in opposite directions to determine macrophyte NPP, with larger sensitivity to changes in vertical growth, and thus maximum flooding levels. Years with uncommonly large flooding amplitude resulted in the highest NPP values, as both horizontal expansion and vertical growth were enhanced under these conditions. Over the simulated period, annual NPP varied by ca. 1.5 (1.06-1.63 TgC yr(-1) ). A small increasing trend in flooding amplitude, and by extension NPP, was observed for the studied period. Variability in growth rates caused by local biotic and abiotic factors, and the lack of knowledge on macrophyte physiological responses to extreme hydrological conditions remain the major sources of uncertainty.
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Inundaciones , Modelos Teóricos , Desarrollo de la Planta , Brasil , Cambio Climático , Simulación por Computador , Ríos , Imágenes SatelitalesRESUMEN
Species of the ant genus Nylanderia constitute some of the most common ground dwelling Formicinae in tropical and subtropical areas. The genus includes numerous species introduced into new regions, especially within urban or disturbed environments. Here, we review the Nylanderia species found within Hong Kong and Macao, which are both highly urbanized regions and of critical importance to Southern China's policy-makers and non-governmental actors concerned with the regional spread of non-native species. A total of 11 species and 2 morphospecies are recorded in Hong Kong and 6 species and 2 morphospecies are recorded in Macao. We also provide a list of new records for the genus in Hong Kong and Macao, along with taxonomic accounts for all the species recorded. Additionally, the present work provides an illustrated identification key for the species of Nylanderia occurring in Southeast Mainland China and Taiwan. We briefly discuss the possible biogeographical implications of our findings, providing additional support to the exotic status of N. bourbonica in continental Southeast Asia. Lastly, we give our perspective on the ramifications of local inaccessibility to type specimens to current taxonomic practices.
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Research findings in natural sciences need to be comparable and reproducible to effectively improve our understanding of ecological and behavioural patterns. In this sense, knowledge frontiers in biodiversity studies are directly tied to taxonomic research, especially in species-rich tropical regions. Here we analysed the taxonomic information available in 470 studies on Brazilian ant diversity published in the last 50 years. We aimed to quantify the proportion of studies that provide enough data to validate taxonomic identification, explore the frequency of studies that properly acknowledge their taxonomic background, and investigate the primary resources for ant identification in Brazil. We found that most studies on Brazilian ant diversity (73.6%) explicitly stated the methods used to identify their specimens. However, the proportion of papers that provide complete data for the repository institutions and vouchered specimens is vanishingly small (5.8%). Additionally, only 40.0% of the studies consistently presented taxon authorities and years of description, rarely referencing taxonomic publications correctly. In turn, the number of specialists and institutions consulted for ant identification in Brazil has increased in the last years, along with the number of studies that explicitly provide their taxonomic procedures for ant identification. Our findings highlight a shift between generations regarding the recognition of taxonomy as fundamental science, deepening our understanding of biodiversity.
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According to the World Health Organization, half of the World's population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF3 group substituted at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC50 values ranging from 0.023 to 20 µM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.
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Antimaláricos/farmacología , Azoles/farmacología , Plasmodium falciparum/efectos de los fármacos , Antimaláricos/síntesis química , Antimaláricos/química , Azoles/síntesis química , Azoles/química , Muerte Celular/efectos de los fármacos , Cloroquina/farmacología , Resistencia a Medicamentos/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Eritrocitos/parasitología , Células Hep G2 , Humanos , Modelos Moleculares , Pirimidinas/síntesis química , Pirimidinas/química , Pirimidinas/farmacología , Quinolinas/químicaRESUMEN
Monitoring biodiversity change is key to effective conservation policy. While it is difficult to establish in situ biodiversity monitoring programs at broad geographical scales, remote sensing advances allow for near-real time Earth observations that may help with this goal. We combine periodical and freely available remote sensing information describing temperature and precipitation with curated biological information from several groups of animals and plants in the Brazilian Atlantic rainforest to design an indirect remote sensing framework that monitors potential loss and gain of biodiversity in near-real time. Using data from biological collections and information from repeated field inventories, we demonstrate that this framework has the potential to accurately predict trends of biodiversity change for both taxonomic and phylogenetic diversity. The framework identifies areas of potential diversity loss more accurately than areas of species gain, and performs best when applied to broadly distributed groups of animals and plants.
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Bosque Lluvioso , Tecnología de Sensores Remotos , Animales , Filogenia , Brasil , Biodiversidad , PlantasRESUMEN
Both freshwater floodplain (várzeas and igapós) forests and brackish-saline mangroves are abundant and well-described ecosystems in Brazil.1 However, an interesting and unique wetland forest exists in the Amazon Delta where extensive mangroves occur in essentially freshwater tidal environments. Unlike the floodplain forests found upriver, the hydrology of these ecosystems is driven largely by large macro-tides of 4-8 m coupled with the significant freshwater discharge from the Amazon River. We explored these mangroves on the Amazon Delta (00°52' N to 01°41' N) and found surface water salinity to be consistently <5; soil pore water salinity in these mangrove forests ranged from 0 nearest the Amazon mouth to only 5-11 at the coastal margins to the north (01°41' N, 49°55' W). We also recorded a unique mix of mangrove-obligate (Avicennia sp., Rhizophora mangle) and facultative-wetland species (Mauritia flexuosa, Pterocarpus sp.) dominating these forests. This unique mix of plant species and soil porewater chemistry exists even along the coastal strands and active coastlines of the Atlantic Ocean. Part of these unique mangroves have escaped current global satellite mapping efforts, and we estimate that they may add over 180 km2 (20% increase in mangrove area) within the Amazon Delta. Despite having a unique structure and function, these freshwater-brackish ecosystems likely provide similar ecosystem services to most mangroves worldwide, such as sequestering large quantities of organic carbon, protection of shoreline ecosystems from erosion, and habitats to many terrestrial and aquatic species (monkeys, birds, crabs, and fish).
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Avicennia , Ecosistema , Animales , Suelo/química , Agua , HumedalesRESUMEN
Acoustic signaling is key in mediating mate choice, which directly impacts individual fitness. Because background noise and habitat structure can impair signal transmission, the acoustic space of mixed-species assemblages has long been hypothesized to reflect selective pressures against signal interference and degradation. However, other potential drivers that received far less attention can drive similar outputs on the acoustic space. Phylogenetic niche conservatism and allometric constraints may also modulate species acoustic features, and the acoustic space of communities could be a side-effect of ecological assembly processes involving other traits (e.g., environmental filtering). Additionally, the acoustic space can also reflect the sorting of species relying on public information through extended communication networks. Using an integrative approach, we revisit the potential drivers of the acoustic space by addressing the distribution of acoustic traits, body size, and phylogenetic relatedness in tropical anuran assemblages across gradients of environmental heterogeneity in the Pantanal wetlands. We found the overall acoustic space to be aggregated compared with null expectations, even when accounting for confounding effects of body size. Across assemblages, acoustic and phylogenetic differences were positively related, while acoustic and body size similarities were negatively related, although to a minor extent. We suggest that acoustic partitioning, acoustic adaptation, and allometric constraints play a minor role in shaping the acoustic output of tropical anuran assemblages and that phylogenetic niche conservatism and public information use would influence between-assemblage variation. Our findings highlight an overlooked multivariate nature of the acoustic dimension and underscore the importance of including the ecological context of communities to understand drivers of the acoustic space.
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Ecosistema , Humedales , Acústica , Animales , Anuros , FilogeniaRESUMEN
Morphological studies of insects can help us to understand the concomitant or sequential functionality of complex structures and may be used to hypothetize distinct levels of phylogenetic relationship among groups. Traditional morphological works, generally, have encompassed a set of elements, including descriptions of structures and their respective conditions, literature references and images, all combined in a single document. Fast forward to the digital era, it is now possible to release this information simultaneously but also independently as data sets linked to the original publication in an external environment. In order to link data from various fields of knowledge, disseminating morphological information in an open environment, it is important to use tools that enhance interoperability. For example, semantic annotations facilitate the dissemination and retrieval of phenotypic data in digital environments. The integration of semantic (i.e. web-based) components with anatomic treatments can be used to generate a traditional description in natural language along with a set of semantic annotations. The ant genus Strumigenys currently comprises about 840 described species distributed worldwide. In the Neotropical region, almost 200 species are currently known, but it is possible that much of the species' diversity there remains unexplored and undescribed. The morphological diversity in the genus is high, reflecting an extreme generic reclassification that occurred in the late 20th and early 21st centuries. Here we define the anatomical concepts in this highly diverse group of ants using semantic annotations to enrich the anatomical ontologies available online, focussing on the definition of terms through subjacent conceptualization.
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Hormigas/anatomía & histología , Terminología como Asunto , Vocabulario Controlado , Anatomía/normas , Animales , Entomología/normasRESUMEN
The current work provides a revised and updated key to the genera of Eucharitidae occurring in the New World, with the major traits of genera illustrated through high-resolution photomicrography. We provide an annotated list of genera and species currently known from Brazil, with a new record for a genus previously unknown for the country. Additionally, we provide a literature revision of the biology and cuticular hydrocarbon profile for the Eucharitidae. The lack of knowledge on the eucharitid Brazilian fauna is briefly discussed.
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Himenópteros , Animales , BrasilRESUMEN
We report finding Strumigenys thaxteri Wheeler in the Amazonian foothills of southeastern Ecuador, over 2000 km to the west of previously known records for the species in Trinidad and Guyana. Field observations suggest it is a sit and wait ambush predator that captures insects that alight on the vegetation upon which they position themselves. Once prey is subdued they descend with it to ground level, where they presumably nest. Their massive mandibles, robust claws, dense body cover of long silky hairs, and sting may all contribute to detecting, trapping, and subduing larger sized, flying prey. This type of predation is hitherto unreported for the genus. Strumigenys reticeps (Kempf), an apparently closely related species from southern Brazil, may share the same behavior but its key morphological traits are of a lesser degree of development than in S. thaxteri. Both species are redescribed and their morphological variability is discussed. High resolution images of both species are provided. The more frequent use of vegetation beating for ant-collecting is urged. Strumigenys lojanensis Lattke Aguirre is synonymized as a junior synonym of S. onorei Baroni Urbani De Andrade.
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Hormigas , Animales , Brasil , Ecuador , Guyana , Trinidad y TobagoRESUMEN
The female of Colocharis hungi Torréns (Hymenoptera: Eucharitidae) is newly described, detailing the characters that distinguish this species. In addition, we provide images and comments for C. hungi, diagnoses for all species of Colocharis Heraty, a key to species, and a distribution map for the species.
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Himenópteros , Avispas , Animales , FemeninoRESUMEN
BACKGROUND AND IMPORTANCE: A variety of deconstructive and reconstructive therapies have been used to treat intracranial aneurysms. The Pipeline embolization device (PED) has become a quite successful option to treat aneurysms, while reconstructing and remodeling the parent vessel. We report a case of off-label PED use, where a flow diverter was placed across the parent vessel of a giant intracranial aneurysm in a novel deconstructive strategy. CLINICAL PRESENTATION: A 40-year-old man with a giant, slow-flow aneurysm of the distal middle cerebral artery (MCA) was treated with the placement of a PED across the vessel containing the aneurysm after superselective test balloon occlusion of that vessel failed. PED was successfully deployed in a competing MCA branch across the origin of the MCA branch supplying the giant aneurysm. The patient continued dual-antiplatelet therapy for 5 months and aspirin monotherapy thereafter. Follow-up angiography, performed 6 months after treatment, demonstrated complete and asymptomatic thrombosis of the aneurysm and its parent MCA branch. A collateral pial and leptomeningeal network developed, reconstructing the distal branches of the occluded MCA branch. After 18 months, the patient remains neurologically intact. CONCLUSION: This appears to be the first description of progressive deconstruction for aneurysm treatment by using PED. Despite not tolerating acute vessel occlusion with superselective test balloon occlusion, the patient was asymptomatic following long-term occlusion with PED secondary to the growth of pial and leptomeningeal collateral networks.
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Embolización Terapéutica/instrumentación , Embolización Terapéutica/métodos , Aneurisma Intracraneal/terapia , Adulto , Aracnoides/diagnóstico por imagen , Aspirina/uso terapéutico , Oclusión con Balón , Angiografía Cerebral , Humanos , Imagenología Tridimensional , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/tratamiento farmacológico , Imagen por Resonancia Magnética , Masculino , Arteria Cerebral Media/diagnóstico por imagen , Piamadre/diagnóstico por imagen , Inhibidores de Agregación Plaquetaria/uso terapéutico , Retratamiento , Trombosis/diagnóstico por imagen , Trombosis/etiología , Tomografía Computarizada por Rayos XRESUMEN
Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.