31 research outputs found
Ecophysiology of fabaceae tree species during forest restoration in the balbina hydroeletric dam in Amazonas state
Plants can adjust functional traits according to the variations in the availability of resources. Under low soil water and nutrient availability, as found in degraded areas, the growth of tree species can be drastically reduced. Tree legumes evolved different strategies to efficiently uptake and use nutrients, securing high survival and growth rates, thus facilitating the restoration of important biogeochemical cycles during forest restoration. Early successional species may increase fast (aquisitive) traits under high resources, while slow (conservative) traits can be enhanced under limited resources and for late successional species. Variations in functional traits such as growth, gas exchange, water potential, nutrients, non-structural carbohydrates (soluble sugars and starch) (NSC), photosynthetic pigments and chlorophyll fluorescence of six tree legumes species were studied according with low vs. high water and nutrient availabilities during a forest restoration plantation in Hydroelectric dam Balbina. The species selected were five native species from Amazonia Cenostigma tocantinum, Senna reticulata, Dipteryx odorata, Clitoria fairchildiana and Inga edulis, and one alien species from Australia Acacia sp.. The individuals were either fertilized or remain unfertilized throughout the 24 month experiment. Three main hypotheses were tested: a) economics spectrum; b) functional equilibrium; and c) NSC dynamics and source-sink allocations. Economics spectrum was mostly confirmed under high water and nutrient availabilities increasing transpiration (E), photosynthesis (P n ), relative growth rates in diameter and performance index of chlorophyll fluorescence (PI ABS ). Traits from the slow spectrum such as dissipation energy flux (DI 0 /RC), intrinsic water use efficiency (IWUE) and root mass fraction (RMF) were enhanced under limited conditions. Functional equilibrium hypothesis was also confirmed as unfertilized plants increased twice the RMF as compared with high nutrient plants. Further RMF was positively correlated with starch and soluble sugars in root tissues indicating an active process of increased root fraction involving energy costs. Acacia sp. which respond differently than economics spectrum had significant growth under severe nutrient limitations, increasing nutrient and energy use efficiency, and the pool of NSC in leaf biomass. S. reticulata also diverge from economics assumptions being unable to adjust traits such as gas exchange and showing responses to drought stress which were related with increased leaf calcium and starch content. The fast acquisition of resources according (increased E and P n ) was considered the main strategy of species in a degraded and fertilized environment, as adjustments in energy use efficiency and NSC pools were essential for plants acclimation. Tree legumes especially N 2 -fixing species are proven to be well succeeded in forest restoration plantations producing eight times more biomass than non N 2 -fixing. Photosynthesis was the most responsive variable to evaluate species responses to resource variations in our study, nonetheless chlorophyll fluorescence appears to be an alternative efficient technique to evaluate the performance and responses to abiotic stress factors. This study makes a significant contribution to the understanting of the ecophysiology of tropica tree legumes and also to provide data to enhance Dynamic Global Vegetation Models. Additionally, from the conceptual view this thesis provide data to enhance climate change predictions models on the interface of soil-plant-atmosphere (during 2015/16 El Niño event) in Amazon forest. In conclusion, the mixing of different successional cological groups and including biological N 2 fixation process appears to be an efficient way to achieve ecological forest restoration goals in nutrient limited soils such as in Amazon basin.Diferentes espécies são capazes de ajustar suas características funcionais de acordo com as
variações na disponibilidade de recursos do ambiente. Sob baixa disponibilidade de água e
nutrientes no solo como em áreas degradadas, o crescimento das plantas pode ser
drasticamente reduzido. Por outro lado, espécies leguminosas arbóreas desenvolveram
evolutivamente diferentes estratégias para adquirir e utilizar nutrientes de maneira eficiente,
garantindo altas taxas de sobrevivência e crescimento, facilitando a restauração de
importantes ciclos biogeoquímicos em plantios de restauração florestal. De acordo com a
hipótese do espectro econômico espécies iniciais podem aumentar respostas relacionadas as
características do rápido espectro sob alta disponibilidade de recursos, enquanto respostas de
crescimento lento (conservacionistas) são encontradas em condições limitantes e em espécies
tardias. As variações das características funcionais como crescimento, trocas gasosas,
nutrientes foliares, potencial hídrico, carboidratos não estruturais (açucares solúveis e amido),
pigmentos fotossintetizantes e fluorescência da clorofila de seis espécies leguminosas
arbóreas foram estudados de acordo com a alta X baixa disponibilidade de agua e nutrientes
em um plantio de restauração florestal na UHE Balbina. Foram selecionadas cinco espécies
nativas da região Cenostigma tocantinum, Senna reticulata, Dipteryx odorata, Clitoria
fairchildiana e Inga edulis, e uma espécie nativa da Austrália Acacia sp. as quais foram
fertilizadas ou permaneceram sem adubação durante os 24 meses de experimento. Três
principais hipóteses foram avaliadas: a) espectro econômico; b) equilíbrio funcional; e c)
dinâmica de carboidratos e relações fonte-dreno. A hipótese do espectro econômico foi
confirmada em condições de alta disponibilidade de água e nutrientes com o aumento da
transpiração (E), fotossíntese (P n ), taxa de crescimento relativo em diâmetro e índice de
desempenho da fluorescência da clorofila (PI ABS ). Características do espectro lento como
dissipação do fluxo de energia (DI 0 /RC), eficiência intrínseca no uso de água (IWUE) e fração
de biomassa de raízes (RMF) foram incrementadas em condições limitantes. A hipótese do
equilíbrio funcional também foi confirmada com um aumento de 100% dos valores de RMF
em plantas não adubadas. Além disso, o aumento da RMF foi correlacionado com os teores de
amido e açúcares solúveis nas raízes indicando um carregamento ativo com gastos de energia
durante o processo. Acacia sp. contrariando o espectro atingiu um crescimento significativo
mesmo não fertilizada, através do ajuste de suas características funcionais com eficiência no
uso de energia (PI ABS ) e nutrientes, além do alto conteúdo de carboidratos e produção de
biomassa de folhas. S. reticulata também divergiu das respostas do espectro, apresentando
sinais de estresse fisiológico como o aumento dos teores de cálcio e amido nas folhas. A
rápida aquisição de recursos como o aumento da P n e da E foi a principal estratégia das
espécies nos ambientes degradados e fertilizados, por outro lado o ajuste na eficiência do uso
de energia e na dinâmica de carboidratos tem papel fundamental na aclimatação das espécies.
Espécies leguminosas arbóreas principalmente fixadoras de N 2 são comprovadamente bem
sucedias em plantios de restauração produzindo oito vezes mais biomassa do que espécies não
fixadoras. A fotossíntese foi a variável mais responsiva para avaliar as respostas das espécies
em relação às variações ambientais, no entanto a fluorescência da clorofila parece ser uma
técnica alternativa robusta e eficaz para avaliar a desempenho e as respostas aos fatores
abióticos de estresse. Concluindo, a inclusão de espécies de diferentes grupos sucessionais e
do processo de fixação biológica de nitrogênio parece ser uma técnica eficiente de restauração
ecológica em áreas com fortes limitações nutricionais como em solos da bacia Amazônica
Carbon and nutrient stocks of three Fabaceae trees used for forest restoration and subjected to fertilization in Amazonia
Amazonia is crucial to global carbon cycle. Deforestation continues to be one of the main causes of the release of C into the atmosphere, but forest restoration plantations can reverse this scenario. However, there is still diffuse information about the C and nutrient stocks in the vegetation biomass. We investigated the carbon and nutrient stocks of Fabaceae trees (Inga edulis, Schizolobium amazonicum and Dipteryx odorata) subjected to fertilization treatments (T1 - no fertilization; T2 - chemical; T3 - organic; and T4 - organic and chemical fertilization) in a degraded area of the Balbina Hydroelectric Dam, AM - Brazil. As an early successional species, I. edulis stocked more C and nutrients than the other two species independent of the fertilization treatment, and S. amazonicum stocked more C than D. odorata under T1 and T4. The mixed species plantation had the potential to stock 4.1 Mg C ha-1 year-1, while I. edulis alone could stock 9.4 Mg C ha-1 year-1. Mixing species that rapidly assimilate C and are of significant ecological and commercial value (e.g., Fabaceae trees) represents a good way to restore degraded areas. Our results suggest that the tested species be used for forest restoration in Amazonia. © 2017, Academia Brasileira de Ciencias. All rights reserved
Uso y prescripción de cannabis medicinal por reumatólogos en Argentina
El uso y prescripción del cannabis y sus derivados en Reumatología está aún en discusión. La ley de cannabis fue sancionada hace casi 3 años, aunque la reglamentación recién está comenzando. El objetivo de este estudio fue conocer la forma en que el reumatólogo se posiciona frente al uso de cannabis en el marco de su práctica médica.
A través de una encuesta realizada durante el Congreso Argentino de Reumatología 2019 se recabó la opinión de 314 médicos que respondieron preguntas acerca del uso, recomendaciones y posturas respecto a la indicación y uso de cannabinoides en su práctica diaria
Ecofunctional traits and biomass production in leguminous tree species under fertilization treatments during forest restoration in Amazonia
Background: Choosing the correct species and fertilization treatments is a determining factor in the success of forest restoration. Methods: A field study was conducted in a degraded area near the Balbina hydroelectric dam in Amazonas State (AM), Brazil, to evaluate two hypotheses: (i) leguminous tree species exhibit differences in growth, leaf nutrient content, and photosynthetic nutrient use efficiencies; and (ii) differences in these characteristics depend on the fertilization treatments to which the species have been subjected. Dipteryx odorata, Inga edulis and Schizolobium amazonicum were subjected to the following treatments: (T1) unfertilized control; (T2) post-planting chemical fertilization; (T3) post-planting organic fertilization and (T4) combined chemical and organic post-planting fertilization. Results: In general, I. edulis had the highest absolute growth rate of biomass under all of the fertilization treatments. I. edulis and S. amazonicum showed the highest growth rates under the T4 treatment. D. odorata showed the greatest responses under the T2 and T4 treatments. Native leguminous trees with higher photosynthetic performance and better nutrient use efficiency exhibited greater growth and biomass production. Conclusion: The results suggest that an adequate balance between leguminous species selection and fertilization will aid in the success of forest restoration in Amazonia. © 2016 by the authors
Asociación entre Artritis Reumatoidea y otras enfermedades autoinmunes
Objetivos: determinar la frecuencia de enfermedades autoinmunes (EAI) en pacientes con Artritis Reumatoidea (AR) y comparar la frecuencia de EAI entre pacientes con AR y sin AR ni otra EAI reumatológica.
Material y Métodos: estudio multicéntrico, observacional, analítico, retrospectivo. Se incluyeron pacientes consecutivos con AR (ACR/EULAR 2010) y como grupo control pacientes con diagnóstico inicial de Osteoartritis primaria (OA).
Latitude gradient influences the age of onset of rheumatoid arthritis : a worldwide survey
The age of onset of rheumatoid arthritis (RA) is an important outcome predictor. Northern countries report an age of RA onset of around 50 years, but apparently, variability exists across different geographical regions. The objective of the present study is to assess whether the age of onset of RA varies across latitudes worldwide. In a proof-of-concept cross-sectional worldwide survey, rheumatologists from preselected cities interviewed 20 consecutive RA patients regarding the date of RA onset (RAO, when the patient first noted a swollen joint). Other studied variables included location of each city, rheumatologist settings, latitudes (10A degrees increments, south to north), longitudes (three regions), intracountry consistency, and countries' Inequality-adjusted Human Development Index (IHDI). Data from 2481 patients (82% females) were obtained from 126 rheumatologists in 77 cities of 41 countries. Worldwide mean age of RAO was 44 +/- 14 years (95% CI 44-45). In 28% of patients, RA began before age 36 years and before age 46 years in 50% of patients. RAO was 8 years earlier around the Tropic of Cancer when compared with northern latitudes (p <0.001, 95% CI 3.5-13). Multivariate analysis showed that females, western cities, and latitudes around the Tropic of Cancer are associated with younger age of RAO (R (2) 0.045, p <0.001). A positive correlation was found between the age of RAO and IHDI (r = 0.7, p <0.01, R (2) 0.5). RA often begins at an early age and onset varies across latitudes worldwide. We postulate that countries' developmental status and their geographical and geomagnetic location influence the age of RAO.Peer reviewe
Escritura pensamiento y lenguaje: Consideraciones acerca de una ética literaria y/o filosófica según Habermas y Derrida
El proyecto filosófico implicado en la deconstrucción derrideana trae como una de sus consecuencias ladesdiferenciación entre fi losofía y literatura. Esto, según Habermas, depotencia el discurso filosófico nosolo en términos epistemológicos sino que también, y muy sensiblemente, en términos ético-normativos. Ladiscusión literatura/filosofia se enmarca por tanto en la más amplia problemática acerca de la legitimidaddel carácter pretendidamente universalista del discurso filo sófico. En este contexto, se revisan algunas delas principales críticas formuladas por Habermas en contra de la estrategia deconstruccionista de Derrida