Nanofertilizer use for adaptation and mitigation of the agriculture/climate change dichotomy effects

Artigo de revisãoAgriculture is considered a significant climate change (CC) driver due to greenhouse gas (GHG) emissions and the loss of fertilizers that contribute to water eutrophication. On the other hand, climate change effects are already impacting agriculture, endangering food security. This paper explores the dichotomies of the effects of agriculture on CC as well as of CC on agriculture, focusing on the contribution that nanofertilizers can bring to this complex system in both directions. The strategies to reduce CC while adapting and mitigating its effects must be a global effort. It is not possible to focus only on the reduction in GHG emissions to stop the effects that are already being felt worldwide. Nanofertilizers, especially slow- and controlled-release nanofertilizers, can reduce the nutrient input and also boost productivity while mitigating some CC effects, such as soil nutrient imbalance and agricultural emissions. As so, this review highlights the benefits of nanofertilizers and their role as a part of the strategy to reduce the reach of CC and mitigate its ever-growing effects, and presents some guidelines for the increased use of these materials in order to enhance their efficacy in this strategy.Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio

Toxicity assessment of Dibutyl phthalate in Grass carp: an integrated biomarker approach

Phthalates are the common plasticisers used around the globe. Dibutyl phthalate (DBP) is a ubiquitous, extensively used in cosmatics and frequently present in the aquatic environment. Therefore, toxic effects of DBP were evaluated in term of oxidative stress and biochemical biomarkers. For this reason, a 21 day exposure was conducted by exposing grass carp with graded concentrations of DBP (1, 10, 100 and 1000 µg/L). After 21days, stress biomarkers:, lipid peroxidation (LPO), catalase (CAT) activity, glutathione-S-transferases (GST) activity and level of reduced glutathione was evaluated in liver, kidney and gills. Alkaline phosphatase (ALP), aspartate transaminase (AST), urea and creatinine were evaluated in liver and kidney homogenates respectively. Moreover, effect of DBP on all biomarkers were evaluated through integrated biomarker response (IBR). Exposure of fish to DBP resulted in oxidative stress in grass carp as evidenced by an increase in lipid peroxidation and decrease in antioxidant enzymes. DBP exposure also resulted in increased liver’s ALT and AST levels. Urea and creatinine were also significantly increased in kidney after exposure to DBP. The IBR showed bad scores as the DBP concentration increased, with the highest one (1000 µg/L) presenting a score >250x the value for the control treatment. Additionally, the IBR/n showed that the most impacted organ was the kidney, followed by the liver and the gills. The obtained results show the need for deeper research into the effects of DBP on fish and their impact on different organs

Osmoregulation of the Cane Toad, Bufo Marinus, in Salt Water

1. Adult cane toads, B. marinus, survived in salinities up to 40% sea-water (SW). 2. Pre-exposure to 30, then 40% SW, increased the survival time of toads in 50% SW. 3. Plasma from toads acclimated to salt water is hyperosmotic to the environment - a result of increased plasma sodium, chloride and urea concentrations. 4. When toads were placed in tap-water and 20% SW, all significant changes to plasma sodium, chloride, urea and osmotic pressure occurred within the first 2 days of exposure. 5. When toads were placed in 30 and 40% SW environments, the increases in plasma sodium and chloride concentrations occurred within the first 2 days of exposure while urea and total osmotic pressure continued to rise until some time between 2 and 7 days exposure

Chitosan as a biostimulant component in nanofertilizers

Comunicação em painelO desenvolvimento de alternativas aos fertilizantes convencionais tem vindo a ganhar destaque nos últimos anos. A necessidade de alimentar a crescente população mundial, as premissas de sustentabilidade a que o mundo se propõe e a necessidade efetiva de combater os efeitos das alterações climáticas, são precursores desta mudança, a par dos preços galopantes que se têm verificado nos inputs de produção. Assim, o desenvolvimento de nanofertilizantes surge como uma oportunidade para o setor agrícola, numa lógica de solução-à-medida e de precisão de aplicação. A inclusão de substâncias bioestimulantes nas formulações deve ser considerada, a fim de aumentar a resistência e a resiliência das culturas aos efeitos das alterações antropogénicas, que já se fazem sentir e que irão piorar nos próximos anos. O quitosano é um polissacarídeo, biocompatível e biodegradável que tem sido utilizado como veículo para outros compostos agrícolas devido às suas propriedades biodegradáveis e não tóxicas. A maior parte da quitina comercial, da qual o quitosano é derivado, é produzida a partir de resíduos de camarões, gambas e caranguejos. Este composto é apontado como tendo efeito bioestimulante para o sistema imunitário das culturas, promovendo efeitos antifúngicos, antivirais, bionematicidas e o reforço de enzimas catalisadoras. Vários estudos relataram melhorias no solo após a sua utilização, como a maior retenção de água e remoção de metais pesados, mas também efeitos benéficos na qualidade da água, pelo controlo de contaminação por algas. Uma vez que as preparações de quitosano são distintas de estudo para estudo, e a componente fitotoxicológica é muitas vezes inexistente, este estudo teve como objetivo alcançar uma formulação de quitosano a ser utilizado em pellets nanofertilizantes e aferir o seu efeito na germinação de Lepidium sativum L. Os ensaios de germinação utilizando Lepidium sativum L., são realizados de acordo com a norma europeia EN 16086-2, onde o índice de comprimento das raízes e o índice de vitalidade de Munoo Liisa são determinados, permitindo qualificar o nível de fitotoxicidade ou o efeito bioestimulante do composto. Neste estudo são realizados dois tratamentos e feita a comparação com o controlo. Em cada modalidade, foram colocadas dez sementes sobre um papel filtro, em placas de Petri de 9 cm de diâmetro e em quadruplicado. Adicionaram-se 3 mL de solução e incubaram-se as placas a 25 ± 2 °C, durante 72 h. As imagens foram tratadas com o software “Image J” e realizou-se a análise de variância a 1 fator, sendo a comparação múltipla de médias realizada através do teste de Tukey (p<0,05). Não é expectável encontrar efeito fitotóxico do composto, mas sim confirmar o efeito bioestimulante do quitosano, utilizado na presente forma, para incorporar o design final dos pellets nanofertilizantes em desenvolvimento.The development of alternatives to conventional fertilizers has been gaining momentum in recent years. The need to feed the growing world population, the premises of sustainability that the world proposes and the effective need to combat the effects of climate change, are precursors of this change, along with the galloping prices that have been registered in production inputs. Thus, the development of nanofertilizers appears as an opportunity for the agricultural sector, in a logic of tailor-made solution and precision of application. The inclusion of biostimulants must be considered in order to increase the resistance and resilience of crops to the effects of anthropogenic changes, which are already being felt and will become worse in the coming years. Chitosan is a biodegradable, biocompatible polysaccharide that has been used as a carrier for other agricultural compounds due to its biodegradable and non-toxic properties. Most commercial chitin, from which chitosan is derived, is produced from shrimp, prawn and crab waste. This compound is reported to have a biostimulant effect on crop immune systems, promoting antifungal, antiviral, bionematicidal effects and enhancing catalytic enzymes. Several studies have reported soil improvements after its use, such as increased water retention and removal of heavy metals, but also beneficial effects on water quality by controlling algal contamination. Since chitosan preparations are distinct from study to study, and the phytotoxicological component is often lacking, this study aimed to achieve a formulation of chitosan to be used in nano fertilizer pellets and to assess the effect on the germination of Lepidium sativum L. Germination tests using Lepidium sativum L., are carried out according to the European standard EN 16086-2, where the root length index and the Munoo-Liisa vitality index are determined, allowing to qualify the level of phytotoxicity or the biostimulant effect of the compound. Two treatments are tested and compared with the control. In each mode, ten seeds were placed on a filter paper, in Petri dishes of 9 cm diameter and in quadruplicate. Then, 3 mL of solution are added and the petri dishes go to incubation at 25 ± 2 °C during 72 h. The images are treated with the software "Image J" and the analysis of variance was performed at 1 factor, being the multiple comparison of means obtained through the Tukey test (p<0.05). It is not expected to find phytotoxic effect of the compound, but rather to confirm the biostimulant effect of chitosan, used in the present form, to incorporate in the final design of the nanofertilizer pellets under development.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Effectiveness of surgery for lumbar spinal stenosis

Background: The management of spinal stenosis by surgery has increased rapidly in the past two decades, however, there is still controversy regarding the efficacy of surgery for this condition. Our aim was to investigate the efficacy and comparative effectiveness of surgery in the management of patients with lumbar spinal stenosis. Methods: Electronic searches were performed on MEDLINE, EMBASE, AMED, CINAHL, Web of Science, LILACS and Cochrane Library from inception to November 2014. Hand searches were conducted on included articles and relevant reviews. We included randomised controlled trials evaluating surgery compared to no treatment, placebo/sham, or to another surgical technique in patients with lumbar spinal stenosis. Primary outcome measures were pain, disability, recovery and quality of life. The PEDro scale was used for risk of bias assessment. Data were pooled with a random-effects model, and the GRADE approach was used to summarise conclusions. Results: Nineteen published reports (17 trials) were included. No trials were identified comparing surgery to no treatment or placebo/sham. Pooling revealed that decompression plus fusion is not superior to decompression alone for pain (mean difference -3.7, 95% confidence interval -15.6 to 8.1), disability (mean difference 9.8, 95% confidence interval -9.4 to 28.9), or walking ability (risk ratio 0.9, 95% confidence interval 0.4 to 1.9). Interspinous process spacer devices are slightly more effective than decompression plus fusion for disability (mean difference 5.7, 95% confidence interval 1.3 to 10.0), but they resulted in significantly higher reoperation rates when compared to decompression alone (28% v 7%, P < 0.001). There are no differences in the effectiveness between other surgical techniques for our main outcomes. Conclusions: The relative efficacy of various surgical options for treatment of spinal stenosis remains uncertain. Decompression plus fusion is not more effective than decompression alone. Interspinous process spacer devices result in higher reoperation rates than bony decompression

Magnetic Charge in a Nonassociative Field Theory

The violation of the Jacobi identity by the presence of magnetic charge is accomodated by using an explicitly nonassociative theory of octonionic fields. It is found that the dynamics of this theory is simplified if the Lagrangian contains only dyonic charges, but certain problems in the constrained quantisation remain. The extension of these concepts to string theory may however resolve these difficulties.Comment: 10 pages, REVTeX, no figure

Hotspots of soil pollution: possible glyphosate and aminomethylphosphonic acid risks on terrestrial ecosystems and human health

The study presents a literature review of glyphosate (GLY) occurrence and its breakdown product, aminomethylphosphonic acid (AMPA), in soils worldwide, but with a specific focus on South America. In addition, an ecological risk approach based on the ecotoxicological endpoints for key soil biota (e.g., collembolans, and earthworms) assessed the impact of GLY and AMPA on these organisms. A generic probabilistic model for human health risk was also calculated for the different world regions. For what reports the risk for edaphic species and the level of pollution under the worst-case scenario, the South American continent was identified as the region of most concern. Nonetheless, other areas may also be in danger, but no risk could be calculated due to the lack of data. Since tropical countries are the top food exporters worldwide, the results obtained in this study must be carefully examined for their implications on a global scale. Some of the factors behind the high levels of these two chemicals in soils are debated (e.g., permissive protection policies, the extensive use of genetically modified crops), and some possible guidelines are presented that include, for example, further environmental characterisation and management of pesticide residues. The present review integrates data that can be used as a base by policymakers and decision-makers to develop and implement environmental policies

Theory and phenomenology of two-Higgs-doublet models

We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment. Various strategies are discussed to control these flavour changing scalar currents and their phenomenological consequences are analysed. In particular, scenarios with natural flavour conservation are investigated, including the so-called type I and type II models as well as lepton-specific and inert models. Type III models are then discussed, where scalar flavour changing neutral currents are present at tree level, but are suppressed by either specific ansatze for the Yukawa couplings or by the introduction of family symmetries. We also consider the phenomenology of charged scalars in these models. Next we turn to the role of symmetries in the scalar sector. We discuss the six symmetry-constrained scalar potentials and their extension into the fermion sector. The vacuum structure of the scalar potential is analysed, including a study of the vacuum stability conditions on the potential and its renormalization-group improvement. The stability of the tree level minimum of the scalar potential in connection with electric charge conservation and its behaviour under CP is analysed. The question of CP violation is addressed in detail, including the cases of explicit CP violation and spontaneous CP violation. We present a detailed study of weak basis invariants which are odd under CP. A careful study of spontaneous CP violation is presented, including an analysis of the conditions which have to be satisfied in order for a vacuum to violate CP. We present minimal models of CP violation where the vacuum phase is sufficient to generate a complex CKM matrix, which is at present a requirement for any realistic model of spontaneous CP violation.Comment: v3: 180 pages, 506 references, new chapter 7 with recent LHC results; referee comments taken into account; submitted to Physics Report

Invariants and flavour in the general Two Higgs Doublet Model

The flavour structure of the general Two Higgs Doublet Model (2HDM) is analysed and a detailed study of the parameter space is presented, showing that flavour mixing in the 2HDM can be parametrized by various unitary matrices which arise from the misalignment in flavour space between pairs of various Hermitian flavour matrices which can be constructed within the model. This is entirely analogous to the generation of the CKM matrix in the Standard Model (SM). We construct weak basis invariants which can give insight into the physical implications of any flavour model, written in an arbitrary weak basis (WB) in the context of 2HDM. We apply this technique to two special cases, models with MFV and models with NNI structures. In both cases non-trivial CP-odd WB invariants arise in a mass power order much smaller than what one encounters in the SM, which can have important implications for baryogenesis in the framework of the general 2HDM