Carbon dynamics of a warm season turfgrass using the eddy-covariance technique

Despite their ubiquitous presence in the urban landscape throughout the United States, scant attention has been given to evaluate the magnitude of net carbon balance from turfgrasses. Warm season turfgrasses, in particular, have largely been understudied for their carbon sequestration potential. With questions being frequently raised on the environment friendliness of warm season turfgrasses, detailed and robust studies focusing on the carbon behavior of such systems are warranted. This study delves into the carbon balance of ‘Tifway’ bermudagrass, the extensively used warm-season turfgrass in Georgia and other subtropical and warm temperate areas. Using the eddy-covariance method, the amount of CO2 captured by a highly managed turfgrass system was measured by deploying two eddy-covariance systems for the study period of 31 months. The results show that ‘Tifway’ bermudagrass is a net sink of carbon, sequestering it at the rate of 4.51–5.15 Mg C ha−1 yr−1. The turf canopy as well as management activities carried out in the farm appear to have a powerful influence on the carbon behavior of the turf. Seasonal and monthly fluxes suggest that turf is an efficient assimilator of carbon during its active growth period of summer and fall months. The results show that the turf sequestered higher amounts of carbon than many agricultural crop systems, supporting the assertion that it is an efficient assimilator of atmospheric carbon. © 201

Potencial de sequestro de carbono em seringais no noroeste do Paraná, Brasil

O plantio de seringueiras é uma opção para melhorar as propriedades físicas e químicas do solo e promover o sequestro de carbono atmosférico, seja na biomassa ou no solo. Apesar das vantagens, o potencial de sequestro de carbono dos seringais no solo e na biomassa não foi ainda avaliado. Um estudo foi conduzido em seringais localizados em Paranapoema, na região noroeste do Paraná, com os objetivos de medir a biomassa em seringais de diferentes idades, e determinar o conteúdo de carbono e o δ13C do solo. O acúmulo de biomassa foi avaliado pelo método destrutivo em seringais de diferentes idades. O estoque total de carbono até 60 cm do solo foi de 63,4 Mg C ha-1 na pastagem adjacente aos seringais, 66,8 e 79,3 Mg C ha-1 nos seringais de 4 e 15 anos de idade, respectivamente, equivalendo a uma taxa anual de aumento de carbono no solo de 0,85 e 1,06 Mg ha-1, sem considerar o acúmulo de carbono pela biomassa da planta. Os valores de δ13C do solo indicaram uma conversão relativamente rápida do carbono proveniente de plantas C4 (pastagem, Brachiaria-Urochloa brizantha) para carbono de plantas C3 (seringal). Os resultados deste estudo indicam o grande potencial de seringais em sequestrar carbono em um período relativamente curto.Rubber tree plantations may improve the soil's physical and chemical properties, and they may sequester atmospheric carbon in the biomass or the soil. However, the potential role of these plantations in sequestering carbon in the soil and plant biomass has not been fully evaluated. This study evaluated rubber tree plantations at Paranapoema, which is located in the northwestern region of the Paraná state of Brazil, to measure the biomass in plantations of different ages and to determine the organic carbon content and δ13C in the soils. Biomass accumulation was evaluated using the destructive method in plantations of different ages. The total carbon stock in the top 60 cm of the soil was 63.4 Mg C ha-1 for the pasture adjacent to the plantations and 66.8 and 79.3 Mg C ha-1 for the 4- and 15-year-old rubber tree plantations, respectively. These values are equivalent to an annual increase in soil carbon stocks of 0.85 and 1.06 Mg ha-1, respectively, and they do not include the accumulation of carbon as tree woody biomass. The soil δ13C indicated a relatively fast conversion from the previous C4-C (pasture; Brachiaria-Urochloa brizantha) to C3-C (rubber tree). The results from this study suggest that rubber tree plantations have untapped potential to sequester carbon over a relatively short time period

Lithium Intercalation in Anatase Titanium Vacancies and the Role of Local Anionic Environment

The structure of bulk and nondefective compounds is generally described with crystal models built from well mastered techniques such the analysis of an X-ray diffractogram. The presence of defects, such as cationic vacancies, locally disrupt the long-range order, with the appearance of local structures with order extending only a few nanometers. To probe and describe the electrochemical properties of cation-deficient anatase, we investigated a series of materials having different concentrations of vacancies, i.e., Ti_{1–<i>x</i>–<i>y</i>}□_{<i>x</i>+<i>y</i>}O_{2–4(<i>x</i>+<i>y</i>)}F_4<i>x</i>(OH)_4<i>y</i>, and compared their properties with respect to defect-free stoichiometric anatase TiO₂. At first, we characterized the series of materials Ti_{1–<i>x</i>–<i>y</i>}□_{<i>x</i>+<i>y</i>}O_{2–4(<i>x</i>+<i>y</i>)}F_4<i>x</i>(OH)_4<i>y</i> by means of pair distribution function (PDF), ¹⁹F nuclear magnetic resonance (NMR), Raman and X-ray photoelectron spectroscopies, to probe the compositional and structural features. Second, we characterized the insertion electrochemical properties vs metallic lithium where we emphasized the beneficial role of the vacancies on the cyclability of the electrode under high C-rate, with performances scaling with the concentration of vacancies. The improved properties were explained by the change of the lithium insertion mechanism due to the presence of the vacancies, which act as host sites and suppress the phase transition typically observed in pure TiO₂, and further favor diffusive transport of lithium within the structure. NMR spectroscopy performed on lithiated samples provides evidence for the insertion of lithium in vacancies. By combining electrochemistry and DFT-calculations, we characterized the electrochemical signatures of the lithium insertion in the vacancies. Importantly, we found that the insertion voltage largely depends on the local anionic environment of the vacancy with a fluoride and hydroxide-rich environments, yielding high and low insertion voltages, respectively. This work further supports the beneficial use of defects engineering in electrodes for batteries and provides new fundamental knowledge in the insertion chemistry of cationic vacancies as host sites

Global parameterization and validation of a two-leaf light use efficiency model for predicting gross primary production across FLUXNET sites:TL-LUE Parameterization and Validation

Light use efficiency (LUE) models are widely used to simulate gross primary production (GPP). However, the treatment of the plant canopy as a big leaf by these models can introduce large uncertainties in simulated GPP. Recently, a two-leaf light use efficiency (TL-LUE) model was developed to simulate GPP separately for sunlit and shaded leaves and has been shown to outperform the big-leaf MOD17 model at six FLUX sites in China. In this study we investigated the performance of the TL-LUE model for a wider range of biomes. For this we optimized the parameters and tested the TL-LUE model using data from 98 FLUXNET sites which are distributed across the globe. The results showed that the TL-LUE model performed in general better than the MOD17 model in simulating 8 day GPP. Optimized maximum light use efficiency of shaded leaves (εmsh) was 2.63 to 4.59 times that of sunlit leaves (εmsu). Generally, the relationships of εmsh and εmsu with εmax were well described by linear equations, indicating the existence of general patterns across biomes. GPP simulated by the TL-LUE model was much less sensitive to biases in the photosynthetically active radiation (PAR) input than the MOD17 model. The results of this study suggest that the proposed TL-LUE model has the potential for simulating regional and global GPP of terrestrial ecosystems, and it is more robust with regard to usual biases in input data than existing approaches which neglect the bimodal within-canopy distribution of PAR

High Cyclin E Staining Index in Blastemal, Stromal or Epithelial Cells Is Correlated with Tumor Aggressiveness in Patients with Nephroblastoma

PURPOSE: Identifying among nephroblastoma those with a high propensity for distant metastases using cell cycle markers: cyclin E as a regulator of progression through the cell cycle and Ki-67 as a tumor proliferation marker, since both are often deregulated in many human malignancies. METHODOLOGY/PRINCIPAL FINDINGS: A staining index (SI) was obtained by immunohistochemistry using anti-cyclin E and anti-Ki-67 antibodies in paraffin sections of 54 postchemotherapy nephroblastoma including 42 nephroblastoma without metastasis and 12 with metastases. Median cyclin E and Ki-67 SI were 46% and 33% in blastemal cells, 30% and 10% in stromal cells, 37% and 29.5% in epithelial cells. The highest values were found for anaplastic nephroblastoma. A correlation between cyclin E and Ki-67 SI was found for the blastemal component and for the epithelial component. Univariate analysis showed prognostic significance for metastases with cyclin E SI in stromal cells, epithelial cells and blastemal cells (p = 0.03, p = 0.01 and p = 0.002, respectively) as well as with Ki-67 SI in blastema (p<10(-4)). The most striking data were that both cyclin E SI and blastemal Ki-67 SI discriminated between patients with metastases and patients without metastasis among intermediate-risk nephroblastoma. CONCLUSIONS: Our findings show that a high cyclin E SI in all components of nephroblastoma is correlated with tumor aggressiveness and metastases, and that assessment of its expression may have prognostic value in the categorization of nephroblastoma