Defoliation frequency and season affected radiation use efficiency and dry matter partitioning to roots of lucerne (Medicago sativa L.) crops

Radiation use efficiency (RUE), and subsequent partitioning between shoots and roots were investigated for ‘Grasslands Kaituna’ lucerne crops grown in the cool temperate climate of Canterbury, New Zealand. Crops were grazed by sheep every 28 or 42 days and yielded 12 and 23 t DM/ha.year, respectively. The RUE for above ground shoots (RUEshoot) was 1.7-2.0 g DM/MJ of intercepted photosynthetically active radiation (PARᵢ) in spring but decreased systematically to ≤1.0 g DM/MJ PARᵢ in autumn. The RUE for total biomass, (RUEtotal) ranged from 1.3 to 3.1 g DM/MJ PARᵢ in response to air temperature and defoliation treatment. The lowest RUEtotal in mid summer for the treatment defoliated every 28 days was related to a 20% decline in the leaf photosynthetic capacity measured at 1000 μmol photons/m2.s (Pn1000) and at saturating light (Pmax). In turn, the reduction in Pn1000 was related to differences in specific leaf nitrogen (SLN), through changes in specific leaf weight (SLW) rather than the leaf N concentration of 4 to 6% DM. The fractional partitioning of DM to roots (proot) increased from near zero in winter/earlyspring to >0.45 in autumn, which explained the observed seasonality of RUEshoot. For the treatment defoliated each 42 days, proot increased linearly from ~0.05 to >0.45 as Pp increased from 10.5 to 16.5 h. In decreasing photoperiods proot averaged 0.45. There was a linear increase (R²=0.52) in proot with Tsoil/Tair but only in the treatment defoliated each 42 days. Agronomic treatments that result in sub optimal N reserves post grazing can be expected to produce conservative canopy characteristics but reduced photosynthetic capacity of the first 5 main stem leaves. Beyond this development stage, canopy expansion may be reduced with more conservative leaf N

Bulk Band Structure of Bi2_2Te3_3

The bulk band structure of Bi$_2$Te$_3$ has been determined by angle-resolved photoemission spectroscopy and compared to first-principles calculations. We have performed calculations using the local density approximation (LDA) of density functional theory and the one-shot $GW$ approximation within the all-electron full-potential linearized augmented-plane-wave (FLAPW) formalism, fully taking into account spin-orbit coupling. Quasiparticle effects produce significant changes in the band structure of \bite~when compared to LDA. Experimental and calculated results are compared in the spectral regions where distinct differences between the LDA and $GW$ results are present. Overall a superior agreement with $GW$ is found, highlighting the importance of many-body effects in the band structure of this family of topological insulators.Comment: 8 pages, 5 Figure

Impact of autumn (fall) dormancy rating on growth and development of seedling lucerne

To quantify the influence of autumn (fall) dormancy (FD) on DM production and phenological development during the seedling phase, three lucerne genotypes with contrasting ratings were grown at Lincoln University, New Zealand. A dormant (FD2), a semi-dormant (FD5), and a winter-active (FD10) genotype were inoculated and sown at a rate of 290 plants/m² on 8 October 2014. By the end of the seedling phase (15 January 2015) the FD10 genotype had produced 20% higher shoot yield and 17% higher root yield than the other two genotypes. The percentage of total biomass partitioned to roots (Proot) was 50% for all genotypes. Total plant biomass (root + shoot yields) was 6.55 t DM/ha for FD10 compared with 5.57 t DM/ha for FD 2 and FD5. Plant height at the open-flower stage was 39.5 cm for FD10 compared with 34.5 cm for FD5 and 33.5 cm for FD2. Maximum leaf area index was similar amongst genotypes at 2.5. However, individual leaf area was 142, 119 and 111 cm²/stem for FD10, FD5 and FD2, respectively. The phyllochron was 52⁰Cd per primary leaf (base temperature of 1⁰C) and consistent amongst genotypes. The number of primary leaves and branches were also conservative at 17 and 14/shoot, respectively. Therefore, differences in shoot yield among these lucerne genotypes during the seedling stage were mainly due to differences in plant height and individual leaf area expansion per plant. This led to greater light interception and therefore higher total biomass accumulation for FD10 than for the other two genotypes

A LA RECHERCHE D'UNE METHODE POUR LA MODELISATION DES PROCESSUS DE DEVELOPPEMENT RURAUX DURABLE DES CONFLITS MULTI-ACTEURS POUR L'USAGE DES RESSOURCES NATURELS AU SUD DE SERGIPE AU BRESIL

N° ISBN - 978-2-7380-1284-5International audienceDesigning a method for rural sustainable development process modelling. This work aims to develop a method for modeling and simulation dynamical aspects of social interaction in rural areas. The project focuses on the study of multi-stakeholder conflicts concerning the use and conservation of natural resources in the context of sustainable rural development. The territory is therefore considered a scenario where the social actors develop systemic and complex relationships. The initial approach is supported by the Sociology of Organized Action by Crozier and Friedberg as theoretical support for understanding the social processes in the South Territory of Sergipe, Brazil. The methodology for social modeling and simulation was based on a constructivist, iterative, exploratory and not predictive approach

Deconstructing agronomic resource use efficiencies to increase food production

Food production per unit land area needs to be increased, thus cropping systems need to use nutrients, water and solar radiation at as close to maximal efficiencies as possible. We deconstruct these efficiencies into their components to define a theoretical crop ideosystem, in which all resource use efficiencies are maximised. This defines an upper biological limit to food production. We then quantify the difference between maximum use efficiencies and those observed in three agronomic systems (maize, cocksfoot, sugarcane) and identify how, in actual farm systems, efficiencies can be raised to raise food production. We find that crop nutrient use efficiency can be limited by low water availability; thus adding nutrients would not raise production but adding water would. The converse situation of water use efficiency being affected by nutrition is not as evident. Ideosystem thinking can be used to define small- and large-scale agronomic systems that optimize water and nutrient use to maximise food production

Laboratórios virtuais: O desenvolvimento de um protótipo para o ensino da química

Como proposta para o presente trabalho, propomos um protótipo de laboratório virtual para o ensino de química, com base nas boas práticas presentes na literatura. O trabalho qualitativo e empírico descritivo segue a metodologia de desenvolvimento de um protótipo, e foi desenvolvido no Departamento de Estatística e Informática da Universidade Federal Rural de Pernambuco, e foi desenvolvido no período de maio de 2016 a maio de 2017.

Oral treatment with the extract of Euterpe oleracea Mart. improves motor dysfunction and reduces brain injury in rats subjected to ischemic stroke

PROPESP-UFPA.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. Centre for the Valorization of Amazonian Bioactive Compounds. Belém, PA, Brazil.Federal University of Pará. Centre for the Valorization of Amazonian Bioactive Compounds. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute Biological Science. Laboratory of Pharmacology and Toxicology of Natural Products. Belém, PA, Brazil.Federal University of Pará. Institute Biological Science. Laboratory of Pharmacology and Toxicology of Natural Products. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Federal University of Pará. João de Barros Barreto University Hospital. Laboratory of Experimental Neuropathology. Belém, PA, Brazil.Ischemic stroke is one of the principal causes of morbidity and mortality around the world. The pathophysiological mechanisms that lead to the formation of the stroke lesions range from the bioenergetic failure of the cells and the intense production of reactive oxygen species to neuroinflammation. The fruit of the açaí palm, Euterpe oleracea Mart. (EO), is consumed by traditional populations in the Brazilian Amazon region, and it is known to have antioxidant and anti-inflammatory properties. We evaluated whether the clarified extract of EO was capable of reducing the area of lesion and promoting neuronal survival following ischemic stroke in rats. Animals submitted to ischemic stroke and treated with EO extract presented a significant improvement in their neurological deficit from the ninth day onward. We also observed a reduction in the extent of the cerebral injury and the preservation of the neurons of the cortical layers. Taken together, our findings indicate that treatment with EO extract in the acute phase following a stroke can trigger signaling pathways that culminate in neuronal survival and promote the partial recovery of neurological scores. However, further detailed studies of the intracellular signaling pathways are needed to better understand the mechanisms involved

Impact of Spatial Soil and Climate Input Data Aggregation on Regional Yield Simulations

This work was financially supported by the German Federal Ministry of Food and Agriculture (BMEL) through the Federal Office for Agriculture and Food (BLE), (2851ERA01J). FT and RPR were supported by FACCE MACSUR (3200009600) through the Finnish Ministry of Agriculture and Forestry (MMM). EC, HE and EL were supported by The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (220-2007-1218) and by the strategic funding ‘Soil-Water-Landscape’ from the faculty of Natural Resources and Agricultural Sciences (Swedish University of Agricultural Sciences) and thank professor P-E Jansson (Royal Institute of Technology, Stockholm) for support. JC, HR and DW thank the INRA ACCAF metaprogramm for funding and Eric Casellas from UR MIAT INRA for support. CB was funded by the Helmholtz project “REKLIM—Regional Climate Change”. CK was funded by the HGF Alliance “Remote Sensing and Earth System Dynamics” (EDA). FH was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) under the Grant FOR1695. FE and SS acknowledge support by the German Science Foundation (project EW 119/5-1). HH, GZ, SS, TG and FE thank Andreas Enders and Gunther Krauss (INRES, University of Bonn) for support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

How do various maize crop models vary in their responses to climate change factors?

Potential consequences of climate change on crop production can be studied using mechanistic crop simulation models. While a broad variety of maize simulation models exist, it is not known whether different models diverge on grain yield responses to changes in climatic factors, or whether they agree in their general trends related to phenology, growth, and yield. With the goal of analyzing the sensitivity of simulated yields to changes in temperature and atmospheric carbon dioxide concentrations [CO2], we present the largest maize crop model intercomparison to date, including 23 different models. These models were evaluated for four locations representing a wide range of maize production conditions in the world: Lusignan (France), Ames (USA), Rio Verde (Brazil) and Morogoro (Tanzania). While individual models differed considerably in absolute yield simulation at the four sites, an ensemble of a minimum number of models was able to simulate absolute yields accurately at the four sites even with low data for calibration, thus suggesting that using an ensemble of models has merit. Temperature increase had strong negative influence on modeled yield response of roughly 0.5 Mg ha 1 per C. Doubling [CO2] from 360 to 720 lmol mol 1 increased grain yield by 7.5% on average across models and the sites. That would therefore make temperature the main factor altering maize yields at the end of this century. Furthermore, there was a large uncertainty in the yield response to [CO2] among models. Model responses to temperature and [CO2] did not differ whether models were simulated with low calibration information or, simulated with high level of calibration information