Middle Miocene closure of the Central American Seaway Montes, C.; Cardona, A.; Jaramillo, C. ...
Science (American Association for the Advancement of Science),
04/2015, Letnik:
348, Številka:
6231
Journal Article
Recenzirano
Uranium-lead geochronology in detrital zircons and provenance analyses in eight boreholes and two surface stratigraphic sections in the northern Andes provide insight into the time of closure of the ...Central American Seaway. The timing of this closure has been correlated with Plio-Pleistocene global oceanographic, atmospheric, and biotic events. We found that a uniquely Panamanian Eocene detrital zircon fingerprint is pronounced in middle Miocene fluvial and shallow marine strata cropping out in the northern Andes but is absent in underlying lower Miocene and Oligocene strata. We contend that this fingerprint demonstrates a fluvial connection, and therefore the absence of an intervening seaway, between the Panama arc and South America in middle Miocene times; the Central American Seaway had vanished by that time.
We introduce the concept of Biome Awareness Disparity (BAD)—defined as a failure to appreciate the significance of all biomes in conservation and restoration policy—and quantify disparities in (a) ...attention and interest, (b) action and (c) knowledge among biomes in tropical restoration science, practice and policy.
By analysing 50,000 tweets from all Partner Institutions of the UN Decade of Ecosystem Restoration, and 45,000 tweets from the main science and environmental news media world‐wide, we found strong disparities in attention and interest relative to biome extent and diversity. Tweets largely focused on forests, whereas open biomes (such as grasslands, savannas and shrublands) received less attention in relation to their area. In contrast to these differences in attention, there were equivalent likes and retweets between forest versus open biomes, suggesting the disparities may not reflect the views of the general public.
Through a literature review, we found that restoration experiments are disproportionately concentrated in rainforests, dry forests and mangroves. More than half of the studies conducted in open biomes reported tree planting as the main restoration action, suggesting inappropriate application of forest‐oriented techniques.
Policy implications. We urge scientists, policymakers and land managers to recognise the value of open biomes for protecting biodiversity, securing ecosystem services, mitigating climate change and enhancing human livelihoods. Fixing Biome Awareness Disparity will increase the likelihood of the United Nations Decade on Ecosystem Restoration successfully delivering its promises.
Resumo
Nós introduzimos o conceito de disparidade de consciência de bioma (DCS)—definido como uma falha em reconhecer a importância de todos os biomas na política de conservação e restauração— e quantificamos disparidades em (i) atenção e interesse, (ii) ação, e (iii) conhecimento na ciência, prática e política de restauração de biomas tropicais.
Analisamos mais de 50,000 tweets de todas as instituições parceiras da Década das Nações Unidas para a Restauração de Ecossistemas, e mais de 45,000 tweets dos maiores canais de mídia de ciência e meio ambiente em todo mundo e encontramos fortes disparidades de atenção e interesse relativos à extensão e diversidade de biomas. Tweets focaram fortemente em florestas, enquanto biomas abertos (como campos, savanas e arbustais), receberam menor atenção relativo à sua área. Em contraste com as disparidades em atenção, encontramos um número equivalente de curtidas e retweets entre biomas florestais e biomas abertos, sugerindo que as disparidades não refletem a visão do público em geral.
Nossa revisão de literatura demonstrou que os experimentos de restauração se concentraram desproporcionalmente em florestas úmidas, secas e manguezais. Mais da metade dos estudos conduzidos em biomas abertos reportou o plantio de árvores como a principal ação de restauração, sugerindo a aplicação incorreta de técnicas centradas em florestas.
Convidamos os cientistas, formuladores de políticas públicas e gestores ambientais a reconhecer o valor dos biomas abertos para proteção da biodiversidade, garantia de serviços ecossistêmicos, mitigação das mudanças climáticas, e melhoria dos meios de subsistência humana. Reparar a Disparidade de Consciência de Bioma aumentará a probabilidade de a Década das Nações Unidas para a Restauração de Ecossistemas cumprir com sucesso suas promessas.
We urge scientists, policymakers and land managers to recognise the value of open biomes for protecting biodiversity, securing ecosystem services, mitigating climate change and enhancing human livelihoods. Fixing Biome Awareness Disparity will increase the likelihood of the United Nations Decade on Ecosystem Restoration successfully delivering its promises.
Abstract
Many quadrupeds are capable of power efficient gaits, especially trot and gallop, thanks to their flexible trunk. The oscillations of the system that includes the backbone, the tendons and ...musculature, store and release elastic energy, helping a smooth deceleration and a fast acceleration of the hindquarters and forequarters, which improves the dynamics of running and its energy efficiency. Forelegs and hindlegs play a key role in generating the bending moment in the trunk. In this paper we present our studies aimed at modeling and reproducing such phenomena for efficient quadrupedal robot locomotion. We propose a model, called mass-mass-spring model, that overcomes the limitation of existing models, and demonstrate that it allows studying how the masses of the legs generate a flexing force that helps the natural bending of the trunk during gallop. We apply our model to six animals, that adopt two different galloping patterns (called
transverse
and
rotatory
), and compare their energy efficiency.
•Reports an umbrella review on risk/protective factors for post-traumatic stress disorder (PTSD).•Several risk factors show convincing evidence of association with PTSD.•Findings may help optimize ...prediction and prevention.
Approximately one third of individuals who experience a severe traumatic event will develop posttraumatic stress disorder (PTSD). It is crucial to identify what factors may be associated with increased or decreased risk for PTSD. We conducted an umbrella review of systematic reviews and meta-analyses of risk/protective factors for PTSD and assessed and graded the evidence of the association between each factor and PTSD. Thirty-three systematic reviews and meta-analyses were included and 130 potential risk factors were identified. Of those, 57 showed a significant association with PTSD. Being female or being indigenous people of the Americas, among the sociodemographic factors; history of physical disease and family history of psychiatric disorder, among the pretrauma factors; and cumulative exposure to potentially traumatic experiences, trauma severity, and being trapped during an earthquake, among the peritrauma factors, showed convincing or highly suggestive evidence of an association with PTSD. Data from prospective studies were less conclusive. Our results have the potential of helping refine PTSD prediction models and contributing to the design of prevention strategies.
The concentration of dissolved CH4 and N2O, as well as the partial pressure of CO2 (pCO2) were studied in the Guadalquivir estuary. Samples were taken in March and April 2018 and 2019, under ...different rainy and tidal conditions. The available database for summer 2017 (Sierra et al., 2020) was included in the interpretation of the factors that determine the variability of these gases in the Guadalquivir estuary. Two different types of samplings were carried out: a longitudinal transect across the river with salinity values close to zero and another one during two consecutive tidal cycles in the mouth of the estuary. The highest concentrations were found in the upper zone of the estuary and during the low tide. This distribution was related to 4 factors: temperature, salinity, exchange with the atmosphere, and biochemical processes together with the river inputs. Temperature is one of the factors that clearly seems to determine the distribution of gases and fluxes, showing the highest values in the upper zone during the summer of 2017. Intense rains cause a dilution effect of the gas in the water column, this provoked, during the season of spring 2018, an increase in the salinity factor in the distribution of gases in the middle zone. High concentrations of the gases have been linked to production processes in the water column, as well as to benthic production and lateral inputs. While the gases concentrations at the mouth presented values close to those of the equilibrium with the atmosphere, the fluxes in the upper zone of the estuary reached average values of 89.6 mmol m-2 d-1, 121.7 μmol m-2 d-1 and 59.9 μmol m-2 d-1 for CO2, CH4 and N2O, respectively. Generally, water-atmosphere fluxes are positive through the whole study, which means that the estuary acts as a source of these gasses to the atmosphere.
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•There is an increase of pCO2, CH4 and N2O towards the upper zone of the estuary.•pCO2, CH4 and N2O variations are coupled with the tidal cycle, with higher values at low tide.•Biochemical processes and inputs is the most important factor affecting the distribution of pCO2, CH4 and N2O.•The estuary acts as a source of pCO2, CH4 and N2O to the atmosphere.
Scientists and policymakers are becoming aware of the pressing need to restore tropical grassy biomes (TGB), which are home to unique biodiversity and provide essential ecosystem services to hundreds ...of millions of people. TGB face increasing threats, including forest‐ and tree‐centric restoration approaches that promote their degradation and we still lack a systematic assessment of where and how TGB restoration research has been done to guide policy and practice.
We synthesized knowledge on field restoration experiments by conducting a systematic literature review to map TGB restoration field studies, examine the association of restoration techniques and degradation sources and investigate the diversity of indicators used to monitor restoration outcomes.
TGB restoration was concentrated at Brazilian and Australian savannas, with large blindspots in Asia, Africa and northern and western South America. Studies were largely context‐dependent, with an inconsistent usage of restoration techniques to different sources of degradation. Less than half of the indicators evaluated were monitored consistently through time, often using a low‐dimensional approach related to ecosystem functioning. Few studies manipulated fire, herbivores and soils, the key drivers for the re‐establishment of TGB dynamics. Unfortunately, many studies lacked negative (degraded ecosystems), positive (reference ecosystems) controls, or both, impairing attempts to robustly determine restoration outcomes.
Our overview of field research on TGB restoration highlights that research needs improvement to refine our ability to assess, plan, implement and monitor restoration. Severe issues with experimental designs and data reporting are identified as barriers to find generality and upscale TGB restoration to meet the goals of the UN Decade on Ecosystem Restoration.
Synthesis and applications. Our synthesis calls for enhanced field experiments, transparent data reporting and quantitative syntheses to guide large‐scale TGB restoration. The overall lack of knowledge on improving resilience and measuring outcomes hampers meaningful comparisons between studies and hinders synthetic views essential for determining appropriate restoration techniques for different degradation sources and suitable monitoring indicators. To overcome the scarcity of reliable and transparent data supporting TGB restoration, we propose a simple checklist for minimum research reporting information and more complete multilingual standardized guidelines.
Resumo
Cientistas e tomadores de decisões estão tomando consciência da urgente necessidade de restaurar biomas tropicais graminosos (BTG), que abrigam uma biodiversidade única e que fornecem serviços ecossistêmicos essenciais a centenas de milhões de pessoas. Os BTG enfrentam ameaças crescentes, incluindo as abordagens de restauração centradas em florestas e árvores, as quais promovem sua degradação, entretanto, ainda não temos uma avaliação sistemática de onde e como a pesquisa sobre a restauração dos BTG tem sido realizada, para orientar as políticas e as práticas.
Nós sintetizamos o conhecimento sobre experimentos de restauração em campo através de uma revisão sistemática da literatura que mapeou estudos de restauração de BTG em campo, examinou a associação das técnicas de restauração com as fontes de degradação, e investigou a diversidade dos indicadores usados para monitorar os resultados da restauração.
A restauração do BTG concentrou‐se nas savanas brasileiras e australianas, com ausência de estudos na Ásia, África e norte e oeste da América do Sul. Os estudos foram amplamente dependentes do contexto, com um uso inconsistente de técnicas de restauração para diferentes fontes de degradação. Menos da metade dos indicadores avaliados foram monitorados de forma consistente ao longo do tempo, muitas vezes utilizando uma abordagem pouco dimensional e relacionada com o funcionamento do ecossistema. Poucos estudos manipularam o fogo, os herbívoros e os solos, que são os principais impulsionadores do restabelecimento da dinâmica dos BTG. Infelizmente, muitos estudos careciam de controles negativos (ecossistemas degradados), positivos (ecossistemas de referência), ou ambos, prejudicando as tentativas de determinar de forma robusta os resultados da restauração.
A nossa visão geral em relação às pesquisas de campo sobre restauração de BTG destaca que a pesquisa precisa melhorar para refinar a nossa capacidade de avaliar, planejar, implementar e monitorar a restauração. Problemas graves com o planejamento experimental e o reporte dos dados são identificados como barreiras para traçar generalidades e escalonar a restauração de BTG de modo a cumprir com as metas da Década da ONU sobre Restauração de Ecossistemas.
Síntese e aplicações. A nossa síntese aponta a necessidade de melhorar os experimentos de campo, a transparência no reporte dos dados e a realização de sínteses quantitativas para orientar a restauração de BTG em grande escala. A falta geral de conhecimentos sobre como favorecer a resiliência e mensurar os resultados dificulta que comparações significativas entre estudos sejam feitas, dificultando a obtenção de visões sintéticas que são essenciais para determinar técnicas de restauração adequadas para diferentes fontes de degradação e os indicadores de monitoramento adequados. Para superar a escassez de dados confiáveis e transparentes que fundamentem a restauração do BTG, nós propomos uma lista de verificação simples que contém informações mínimas de relatórios de pesquisa e um guia multilíngue padronizado e mais completo.
Our synthesis calls for enhanced field experiments, transparent data reporting and quantitative syntheses to guide large‐scale TGB restoration. The overall lack of knowledge on improving resilience and measuring outcomes hampers meaningful comparisons between studies and hinders synthetic views essential for determining appropriate restoration techniques for different degradation sources and suitable monitoring indicators. To overcome the scarcity of reliable and transparent data supporting TGB restoration, we propose a simple checklist for minimum research reporting information and more complete multilingual standardized guidelines.
Background
Epidemiological studies demonstrate a link between gastrointestinal cancers and environmental factors such as diet. It has been suggested that environmental cancer risk is determined by ...the interaction between diet and microbes. Thus, the purpose of this study was to examine the hypothesis that microbiota composition during colorectal cancer (CRC) progression might differ depending on the stage of the disease.
Methods
A total of 28 age-matched and sex-matched subjects, seven with CRC adenocarcinoma, 11 with tubular adenomas and ten healthy subjects with intact colon, were included into the study. Microbiomes from mucosal and fecal samples were analyzed with 16
S
ribosomal RNA gene pyrosequencing, together with quantitative PCR of specific bacteria and archaea.
Results
The principal coordinates analysis clearly separated healthy tissue samples from polyps and tumors, supporting the presence of specific bacterial consortia that are associated with affected sites and that can serve as potential biomarkers of CRC progression. A higher presence of
Fusobacterium nucleatum
and
Enterobacteriaceae
was found by qPCR in samples from CRC compared to healthy controls. We observed a correlation between CRC process development and levels of Methanobacteriales (
R
= 0.537,
P
= 0.007) and
Methanobrevibacterium
(
R
= 0.574,
P
= 0.03) in fecal samples.
Conclusion
Differences in microbial and archaeal composition between mucosal samples from healthy and disease tissues were observed in tubular adenoma and adenocarcinoma. In addition, microbiota from mucosal samples represented the underlying dysbiosis, whereas fecal samples seem not to be appropriate to detect shifts in microbial composition. CRC risk is influenced by microbial composition, showing differences according to disease progression step and tumor severity.
Graphene combines unique electronic properties and surprising quantum effects with outstanding thermal and mechanical properties. Many potential applications, including electronics and ...nanocomposites, require that graphene be dispersed and processed in a fluid phase. Here, we show that graphite spontaneously exfoliates into single-layer graphene in chlorosulphonic acid, and dissolves at isotropic concentrations as high as approximately 2 mg ml(-1), which is an order of magnitude higher than previously reported values. This occurs without the need for covalent functionalization, surfactant stabilization, or sonication, which can compromise the properties of graphene or reduce flake size. We also report spontaneous formation of liquid-crystalline phases at high concentrations ( approximately 20-30 mg ml(-1)). Transparent, conducting films are produced from these dispersions at 1,000 Omega square(-1) and approximately 80% transparency. High-concentration solutions, both isotropic and liquid crystalline, could be particularly useful for making flexible electronics as well as multifunctional fibres.
The Mar Menor is a hypersaline coastal lagoon with salinity values ranging from 41.9 to 45.5. The system is subjected to a high anthropic pressure that causes an intense eutrophication process, ...followed by a recovery of the macrophyte meadows. This study focuses on the distribution of the main greenhouse gases (CO2, CH4 and N2O) and was carried out in the extreme seasonal conditions of winter and summer during the year 2018. Sediment-water-atmosphere exchanges and biochemical processes in the water column appeared to be the main factors to explain the variability of these gases.
Dissolved Inorganic Carbon (DIC), CH4 and N2O benthic fluxes values obtained in this study, were of 91 ± 29 mmol m−2 d−1, 3.9 ± 1.9 μmol m−2 d−1 and −0.65 μmol m−2 d−1, respectively, along with an important seasonal variation observed, with an increase of DIC and CH4 benthic fluxes during the summer season. Mean values of partial pressure of CO2 (pCO2) in surface water were of 579 μatm in winter and 464 μatm in summer, therefore we can establish that the Mar Menor acts as a source of this gas emitting 3.3 ± 3.0 mmol CO2 m−2 d−1 to the atmosphere. In spite of this, the Mar Menor has a strong autotrophic behaviour partly due to the recovery of the macrophyte meadows, presenting an estimated NEP of 101 mmol m−2 d−1. Regarding to CH4, the mean fluxes to the atmosphere were of 8.0 ± 5.8 μmol m−2 d−1 and there was evidence of CH4 production in the water column that increased in summer. Last of all, in the case of N2O the system acts as a sink with values of −0.65 ± 0.5 μmol m−2 d−1, presenting an intake of N2O that is usually detected in pristine systems.
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•This coastal lagoon acts as a source of CO2 and CH4, but as a sink for N2O.•The benthic fluxes of CO2 and CH4 are an important contribution to the water column.•There is a significant intake of N2O in the sediment.•The Mar Menor is strongly autotrophic during the recovery of macrophyte meadows.•Unbalanced sediment-water-air CH4 fluxes suggest water column production.
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