Did belowground N transfer in mixed plantations of Acacia mangium and Eucalyptus meet the Stress Gradient Hypothesis?

Belowground interactions in mixed forest plantations remain poorly understood as that of short-tenn nitrogen (N) transfer from N-fixing trees to non-N-fixing trees (Non-NFT) depending on nutrient availability. We investigated in this facilitation process met the Stress Gradient Hypothesis. which predicts that under stressful environmental conditions competition decreases and facilitation increases. A 15N pulse-labelling study was conducted in a five-year-old mixture of 50% Eucalyptus grandis x E. urophylla and 50% Acacia mangium with the hypothesis of higher transfer from acacia when no fertilization was applied. A complete randomized block design was set up with three replicates of fertilized and non-fertilized mixture. In each treatment of each block, a labeled solution of potassium nitrate (98 atom% 15N-N03) was injected into the stem of an Acacia tree with the same basal area as the average of the stand. The x (15N) was monitored over two months in each labeled acacia and four neighboring eucalypts. For both species, young leaves and tine roots were sampled at 7.14 and 30 days after injection. After 60 days. the x (15N) was determined in the wood, bark, branches, total foliage and fine roots of the 6 labeled acacias and 12 eucalypts trees The preliminary results showed that complete absorption of the labeled solution occurred between 28 and 60 days after labeling depending on Acacia trees and treatments. The dynamics in the proportion of Eucalyptus N derived from transfer will give insights into how this process may promote N nutrition of non-NFTs growing in unfertile tropical soils

Habitat use, daily activity periods, and thermal ecology of Ameiva ameiva (Squamata: Teiidae) in a caatinga area of northeastern Brazil.

Estudamos o uso dos recursos espaciais, temporais e térmicos pelo lagarto neotropical Ameiva ameiva durante as estaçõesseca e chuvosa em um ambiente de caatinga do nordeste do Brasil. Os lagartos utilizaram os hábitats e micro-hábitats de vegetação baixa, mas nunca foram observados no hábitat rochoso. Os adultos utilizaram usualmente o hábitat arbóreo-arbustivo, enquanto os juvenis foram observados maisfrequentemente no hábitat arbustivo-herbáceo. Diferenças ontogenéticas no uso do espaço parecem estar relacionadas a diferentes necessidades térmicas entre as classes de idade devido a diferenças de tamanho corporal. As temperaturas corporais dos juvenis foram significativamente maiores que asdos adultos. A maioria das espécies de Teiidae possui temperaturas corporais elevadas, usualmente acima de 37oC, e atividade concentrada nas horas mais quentes do dia, como observado em A. ameiva neste estudo. A sazonalidade influenciou o uso do hábitat e os períodos diários de atividade dos adultos, mas não influenciou as temperaturas corporais. Verificamos flutuações anuais na abundância de indivíduos adultos, com um declínio de lagartos ativos na estação seca; esse fenômeno pode estar relacionado à estivação e/ou ao aumento da taxa de mortalidade durante os meses mais secos.We studied the use of spatial, temporal, and thermal resources by the Neotropical lizard Ameiva ameiva during rainy and dry seasons in a caatinga (xerophilous open forests) environment in northeastern Brazil. Lizards used the vegetation habitats and microhabitats in the ground, but never were seen in the rocky habitat. Adults usually used the arboreal-shrubby habitat, whereas juveniles were sighted more often in the shrubby-herbaceous habitat. Ontogenetic differences in spatial use seem to be linked to different thermal needs between age groups owing to differences in body size. Body temperatures were significantly higher in juveniles than in adults. Most teiid species have elevated body temperatures, usually above 37oC,and are active during the hottest times of day, as was observed for A. ameiva in this study. Seasonality influenced habitat use and daily activity periods of adults, but not body temperatures. We verified annual fluctuations in adult abundance, with a decline of active lizards in the dry season; this phenomenon may be related to aestivation and/or increased mortality rate during the driest months

Organic farming take off in Portugal

Organic farming is booming in Portugal. CAP subsidies are the main reason beyond this boom. Converted farms are still a small proportion of the country’s total farms. They are mostly extensive (low input) Mediterranean farms located in the mainland interior and less developed regions. Large farms and highly educated farmers are the ones converting. Olive oil is the main organic production. The market for organic products in Portugal is segmented and distribution channels are narrow. In general, people are not aware of organic products and/or lack the money to pay the required price premium. However, a segment of highly educated consumers with above average income do exist. Two private bodies provide certification for organic products under the supervision of the Government. Several national and regional Associations provide technical support, training and education to farmers but they face many barriers. The lack of public environmental education and the lack of research on the sector constitute other important institutional barriers to the Portuguese organic sector development

An additional brain endocast of the ictidosaur riograndia guaibensis (Eucynodontia: Probainognathia): Intraspecific variation of endocranial traits

Recently, the morphology and encephalization of the brain endocast of the Triassic non-mammaliaform probainognathian cynodont Riograndia guaibensis were studied. Here, we analyzed the brain endocast of an additional specimen of this species. The new endocast shows well-defined olfactory bulbs and a median sulcus dividing the hemispheres, traits that were not clearly observed in the first studied specimen. Encephalization quotients were also calculated, revealing similar values to other non-mammaliaform cynodonts and lower than those of the first analyzed specimen. The analyzed cranium is slightly larger than the first studied one and may represent an advanced ontogenetic stage. Hence, these differences may be related to the intraspecific variation of this cynodont or alternatively, to the preservation of each specimen.Fil: Kerber, Leonardo. Universidade Federal de Santa Maria; BrasilFil: Ferreira, José Darival. Universidade Federal de Santa Maria; BrasilFil: Fonseca, Pedro Henrique M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Franco, Arymatheia. Universidade Federal de Santa Maria; BrasilFil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Soares, Marina Bento. Universidade Federal do Rio Grande do Sul; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Ribeiro, Ana Maria. Universidade Federal do Rio Grande do Sul; Brasi

Functional characterization and target discovery of glycoside hydrolases from the digestome of the lower termite Coptotermes gestroi

<p>Abstract</p> <p>Background</p> <p>Lignocellulosic materials have been moved towards the forefront of the biofuel industry as a sustainable resource. However, saccharification and the production of bioproducts derived from plant cell wall biomass are complex and lengthy processes. The understanding of termite gut biology and feeding strategies may improve the current state of biomass conversion technology and bioproduct production.</p> <p>Results</p> <p>The study herein shows comprehensive functional characterization of crude body extracts from <it>Coptotermes gestroi </it>along with global proteomic analysis of the termite's digestome, targeting the identification of glycoside hydrolases and accessory proteins responsible for plant biomass conversion. The crude protein extract from <it>C. gestroi </it>was enzymatically efficient over a broad pH range on a series of natural polysaccharides, formed by glucose-, xylose-, mannan- and/or arabinose-containing polymers, linked by various types of glycosidic bonds, as well as ramification types. Our proteomic approach successfully identified a large number of relevant polypeptides in the <it>C. gestroi </it>digestome. A total of 55 different proteins were identified and classified into 29 CAZy families. Based on the total number of peptides identified, the majority of components found in the <it>C. gestroi </it>digestome were cellulose-degrading enzymes. Xylanolytic enzymes, mannan- hydrolytic enzymes, pectinases and starch-degrading and debranching enzymes were also identified. Our strategy enabled validation of liquid chromatography with tandem mass spectrometry recognized proteins, by enzymatic functional assays and by following the degradation products of specific 8-amino-1,3,6-pyrenetrisulfonic acid labeled oligosaccharides through capillary zone electrophoresis.</p> <p>Conclusions</p> <p>Here we describe the first global study on the enzymatic repertoire involved in plant polysaccharide degradation by the lower termite <it>C. gestroi</it>. The biochemical characterization of whole body termite extracts evidenced their ability to cleave all types of glycosidic bonds present in plant polysaccharides. The comprehensive proteomic analysis, revealed a complete collection of hydrolytic enzymes including cellulases (GH1, GH3, GH5, GH7, GH9 and CBM 6), hemicellulases (GH2, GH10, GH11, GH16, GH43 and CBM 27) and pectinases (GH28 and GH29).</p

\u3cem\u3eTithonia diversifolia\u3c/em\u3e for Ruminant Nutrition

India and Brazil lead the world ranking of livestock enteric methane emissions (FAO 2006). According to FAO (2006), Brazil (9.6 Tg of CH4/year) is the highest emitter of methane from cattle, followed by India (8.6 Tg of CH4/year) and the USA (5.1 Tg of CH4/year). In livestock, methane (CH4) formed from enteric fermentation of carbohydrates is primarily responsible for the emissions in the sector. Regarding livestock methane emission, Delgado et al. (2012) evaluated 20 tree and shrub species using in vitro technique and demonstrated a reducing effect on the amount of methane when Tithonia diversifolia was compared with, for example, Cynodon nlemfuensis grass. Tithonia diversifolia belongs to the division - Sphermatophyta; class - Eudicotiledoneae; sub-class - Metaclamídeas; Order - Campanulate; Family - Asteraceae; Genre - Tithonia, and Species - Tithonia diversifolia (Hemsl.), Gray (Souza 2008). Tithonia diversifolia can be very useful in animal nutrition (Fig. 1) by increasing the protein content of animal diet at low cost (Murgueitio et al. 2010) as well as in the recovery of degraded soils for it grows in areas with low levels of fertility and has high ability to absorb phosphorus, even if it is unavailable to other forage species (Kwabiah et al. 2003). The objective of this study was to assess the nutritional qualities, including quantification of enteric methane generated during in vitro ruminal fermentation, of Tithonia diversifolia as an alternative forage for ruminant nutrition in the tropics

Relaxation processes in harmonic glasses?

A relaxation process, with the associated phenomenology of sound attenuation and sound velocity dispersion, is found in a simulated harmonic Lennard-Jones glass. We propose to identify this process with the so called microscopic (or instantaneous) relaxation process observed in real glasses and supercooled liquids. A model based on the memory function approach accounts for the observation, and allows to relate to each others: 1) the characteristic time and strength of this process, 2) the low frequency limit of the dynamic structure factor of the glass, and 3) the high frequency sound attenuation coefficient, with its observed quadratic dependence on the momentum transfer.Comment: 11 pages, 3 figure

Moisture Control, Inoculant and Particle Size in Tropical Grass Silages

Decreased fermentation and spoilage losses with improved aerobic stability during feed out can be accomplished by several strategies, such as wilting, addition of microbial additives and moisture absorbents. Particle size reduction may increase bulk density and improve the fermentation. The objective of this trial was to evaluate the effects of particle size, moisture content and a microbial additive on chemical-physical parameters and losses in silages made from Tanzania grass

Elastic constant dishomogeneity and Q2Q^2 dependence of the broadening of the dynamical structure factor in disordered systems

We propose an explanation for the quadratic dependence on the momentum $Q$, of the broadening of the acoustic excitation peak recently found in the study of the dynamic structure factor of many real and simulated glasses. We ascribe the observed $Q^2$ law to the spatial fluctuations of the local wavelength of the collective vibrational modes, in turn produced by the dishomegeneity of the inter-particle elastic constants. This explanation is analitically shown to hold for 1-dimensional disordered chains and satisfatorily numerically tested in both 1 and 3 dimensions.Comment: 4 pages, RevTeX, 5 postscript figure