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141.
Clever Briedis João Carlos de Moraes Sá Eduardo Fávero Caires Jaqueline de Fátima Navarro Thiago Massao Inagaki Adriane Boer Caio Quadros Neto Ademir de Oliveira Ferreira Lutécia Beatriz Canalli Josiane Burkner dos Santos 《Geoderma》2012
The stabilisation of soil organic matter (SOM) is the result of the simultaneous action of three mechanisms: chemical stabilisation, biochemical stabilisation and physical protection. The objectives of this study were (i) to evaluate carbon-protection mechanisms in different SOM pools in soil aggregates and (ii) to identify the association of Ca2 + with total organic carbon (TOC) under the influence of surface liming in a medium-textured Oxisol in a long-term experiment under no-till system (NTS) in southern Brazil (25° 10′ S, 50° 05′ W). The treatments consisted of application of zero or 6 tons ha? 1 of dolomitic lime on the soil surface in 1993 and a reapplication of zero or 3 tons ha? 1 of dolomitic lime in 2000 to plots with or without previous lime application. Soil samples collected at depths of 0–2.5, 2.5–5, 5–10 and 10–20 cm were separated into seven aggregate classes. In each of these classes, TOC, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) were analysed. The 8–19 mm sized aggregates from the 0–2.5 cm layer were assessed by energy-dispersive X-ray spectroscopy (EDS) for the elemental analysis of carbon (C) and calcium (Ca). The liming caused an accumulation of TOC in the aggregates, mainly at a depth of 0–2.5 cm. The aggregates from soils treated with lime had a higher mean weight diameter (MWD) that resulted in the accumulation of TOC, especially in the 8–19 mm aggregate class, that was linear and closely related with C input (R2 = 0.99). The proportion of large aggregates in the treatments with lime was closely correlated with the TOC content of the whole sample. The largest dose of lime (9 tons ha? 1) resulted in higher TOC, POC and MAOC values, mainly in the 8–19 mm aggregate class. The elemental analyses for C and Ca revealed similar spectra between them for the surface-liming treatments in the clay fraction found in the centres of the 8–19 mm aggregates. The surface application of lime to NT fields provided greater stability and protection of the intra-aggregate C, presumably due to Ca2 + acting as a cationic bridge between OC and the kaolinite in the clay fraction. 相似文献
142.
H M Khatib A Shaari K Abas F Shitan M Kneer R Neto V Lajis NH 《Journal of agricultural and food chemistry》2012,60(1):410-417
The metabolites of three species of Apiaceae, also known as Pegaga, were analyzed utilizing (1)H NMR spectroscopy and multivariate data analysis. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) resolved the species, Centella asiatica, Hydrocotyle bonariensis, and Hydrocotyle sibthorpioides, into three clusters. The saponins, asiaticoside and madecassoside, along with chlorogenic acids were the metabolites that contributed most to the separation. Furthermore, the effects of growth-lighting condition to metabolite contents were also investigated. The extracts of C. asiatica grown in full-day light exposure exhibited a stronger radical scavenging activity and contained more triterpenes (asiaticoside and madecassoside), flavonoids, and chlorogenic acids as compared to plants grown in 50% shade. This study established the potential of using a combination of (1)H NMR spectroscopy and multivariate data analyses in differentiating three closely related species and the effects of growth lighting, based on their metabolite contents and identification of the markers contributing to their differences. 相似文献
143.
144.
José Fernandes Silva‐Neto Alberto Jorge Pinto Nunes Hassan Sabry‐Neto Marcelo Vinícius Carmo Sá 《Aquaculture Research》2012,43(3):430-437
The present work aimed at studying the growth performance and feeding preference of Litopenaeus vannamei juveniles fed on diets supplemented or not with Spirulina meal. Litopenaeus vannamei juveniles (3.89 ± 0.25 g) were stocked for 72 days in 28 round 500‐L tanks at 44 shrimp/tank (77 juveniles/m2). The diets were supplemented with 0.5% of a commercial feed attractant (C25 and C50) or with Spirulina meal (S25 and S50). In C25/S25 and C50/S50 there were reductions of 25% and 50% in fishmeal inclusion level respectively. In a further study, two feeding trays with different diets were allowed to shrimp at the same moment and they were located in opposite walls of the tank. The feed remains in each feeding tray were collected and weighted to calculate the dry feed remains. The weekly growth rate of shrimp fed on S25 (0.89 ± 0.03 g) was not significantly different from those fed on C25 (0.89 ± 0.01 g). The attractiveness experiment showed that S25 was preferred significantly more by shrimp than C25. In conclusion, Spirulina meal added at 0.5% in a complete diet for L. vannamei juveniles, with 14% of Peruvian fishmeal, has proved itself as a nutritionally efficient feeding attractant. 相似文献
145.
146.
Rodrigo Hakamada Carmeni Giunti Neto Cristiane CZ de Lemos Sérgio R Silva Marina SG Otto Kevin B Hall 《Southern Forests》2016,78(4):275-281
Leaf area index (LAI) is a key ecophysiological parameter in forest stands because it characterises the interface between atmospheric processes and plant physiology. Several indirect methods for estimating LAI have been developed. However, these methods have limitations that can affect the estimates. This study aimed to evaluate the accuracy and applicability of a visual method for estimating LAI in clonal Eucalyptus grandis × E. urophylla plantations and to compare it with hemispherical photography, ceptometer and LAI-2000® estimates. Destructive sampling for direct determination of the actual LAI was performed in 22 plots at two geographical locations in Brazil. Actual LAI values were then used to develop a field guide with photographic images representing an LAI range of 1.0–5.0 m2 m?2 (leaf area/ground area). The visual LAI estimation guide was evaluated with 17 observers in the field. The average difference between actual LAI and visual LAI estimation was 12% and the absolute difference between the two methods was less than or equal to 0.5 m2 m?2 in 77% of plots. Pearson’s correlation coefficients were high between actual LAI and hemispherical photographs (0.8), visual estimation (0.93) and LAI-2000® (0.99) and low for the ceptometer (0.18). However, absolute values differed among methods, with the average difference between the actual and estimated LAI of [12]% for visual estimation, 28% for the LAI-2000®, 37% for the ceptometer and ?43% for hemispherical photographs. The LAI-2000® and ceptometer overestimated LAI in all plots, whereas hemispherical photographs underestimated the values in all measurements, showing that these methods need calibration to be used. No differences were observed between actual LAI and visual estimates across stand ages of 2–8 years and LAI of 1.5–5.3 m2 m?2 (P > 0.05). The results show that visual estimation of LAI in Eucalyptus stands is a practical method that is unaffected by atmospheric characteristics and can be used on an operational scale. 相似文献
147.
Primary amoebic meningoencephalitis is an acute disease of the central nervous system of humans and animals caused by Naegleria fowleri. This report describes a case of meningoencephalitis caused by N. fowleri in a crossbred, one-year-old bovine with progressive neurological signs. At necropsy there was thickening of the meninges and multifocal areas of malacia in the thalamus, caudal and rostral colliculi, parietal and occipital cortex, and cerebellum. Histologically there was multifocal necrosupurative meningoencephalitis associated with areas of malacia containing amoebic trophozoites. Immunohistochemistry of the brain was positive for N. fowleri. The disease should be included among the differential diagnosis of diseases of the central nervous system in cattle in areas where animals are exposed to hot, stagnant water. 相似文献
148.
Maria Izabel Gomes Silva Maria Anglica Gomes Silva Manuel Rufino de Aquino Neto Brinell Arcanjo Moura Helenira Loureno de Sousa Everton Paulo Homem de Lavor Patrícia Freire de Vasconcelos Danielle Silveira Macêdo Damio Pergentino de Sousa Silvnia Maria Mendes Vasconcelos Francisca Cla Floreno de Sousa 《Fitoterapia》2009,80(8):506-513
The present study investigated the effects of isopulegol, a monoterpene alcohol, in PTZ-induced convulsions and verified possible involved mechanisms. Saline, isopulegol or diazepam were intraperitonealy injected 30 min before PTZ. The latency for development of convulsions and mortality, as well as the mortality protection percentage was recorded. For investigating the involvement of GABAergic system, flumazenil was utilized. The activity of antioxidant enzyme catalase as well as the levels of reduced glutathione and lipid peroxidation were measured in brain hippocampus. Similarly to diazepam, isopulegol significantly prolonged the latency for convulsions and mortality of mice. All animals were protected against mortality at higher dose of isopulegol. Flumazenil pretreatment decreased the prolongation of seizure latency induced by both diazepam and isopulegol, although it was not able to reverse the latency and protection percent for mortality. Isopulegol also significantly prevented PTZ-induced increase in lipid peroxidation, preserved catalase activity in normal levels, and prevented the PTZ-induced loss of GSH in hippocampus of mice. These results suggest that the anticonvulsant and bioprotective effects of isopulegol against PTZ-induced convulsions are possibly related to positive modulation of benzodiazepine-sensitive GABAA receptors and to antioxidant properties. 相似文献
149.
Semiochemicals to enhance herbivory by Diorhabda carinulata aggregations in saltcedar (Tamarix spp.) infestations 下载免费PDF全文
Alexander M Gaffke Sharlene E Sing Tom L Dudley Daniel W Bean Justin A Russak Agenor Mafra‐Neto Paul A Grieco Robert KD Peterson David K Weaver 《Pest management science》2018,74(6):1494-1503
BACKGROUND
Semiochemicals for monitoring, attracting or repelling pest and beneficial organisms are increasingly deployed in agricultural and forest systems for pest management. However, the use of aggregation pheromones and host‐plant attractants for the express purpose of increasing the efficacy of classical biological control agents of weeds has not been widely reported. Therefore, we conducted field‐based assays to determine if a specialized wax‐based matrix impregnated with an aggregation pheromone of the northern tamarisk beetle Diorhabda carinulata (Desbrochers) or host‐plant volatiles could increase the efficacy of D. carinulata.RESULTS
The aggregation pheromone and host‐plant volatiles were formulated for field application using a wax‐based matrix. Reported release rates suggest that this matrix is a viable formulation for enhancing D. carinulata aggregations under field conditions. Pheromone‐treated saltcedar plants (Tamarix spp.) not only had higher densities of adult and larval D. carinulata, but also sustained greater levels of foliar damage than control plants. Increased damage from the focused feeding of D. carinulata caused an increase in foliar dieback and decrease in live canopy volume of semiochemical‐treated plants.CONCLUSION
Field deployment of these semiochemical formulations could be useful in directing populations of D. carinulata for increased impact on Tamarix spp. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献150.
Effects of selenium supplementation on the oxidative state of acute heat stress‐exposed quails 下载免费PDF全文
A. P. Del Vesco E. Gasparino V. Zancanela D. O. Grieser C. E. Stanquevis P. C. Pozza A. R. Oliveira Neto 《Journal of animal physiology and animal nutrition》2017,101(1):170-179
This study aimed to evaluate the effect of heat stress (HS) and selenium supplementation on markers of stress, meat quality and gene expression. For this, meat quails of 42 days of age were fed a diet that either met [0.33 mg/kg, nutritional demand for selenium (SS)] or did not meet [0.11 mg/kg, selenium deficient (SD)] the nutritional demands for selenium during the 7 days of evaluation. In addition, the animals were kept at either a thermal comfort temperature (25 °C) or exposed to HS (38 °C for 24 h). Glutathione synthetase (GSS), glutathione reductase (GSR) and uncoupling protein (UCP) gene expression were influenced by the interaction between temperature and diet. Animals subjected to HS and fed the SS diet exhibited the highest GSS and GSR gene expression. In terms of UCP gene expression, the lowest values were observed in HS animals on the SD diet. Glutathione peroxidase 7 (GPX7) gene expression, body temperature (BT) and creatine kinase (CK) activity were influenced by both selenium supplementation and HS. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) activity and creatinine content all were influenced by the diet/environment interaction. The highest AST activity, ALT activity and creatinine levels were observed in animals that were both on the SD diet and exposed to HS. HS animals also exhibited an increased heterophil/lymphocyte ratio and lower triiodothyronine (T3) hormone levels than birds that remained at the comfortable temperature. Animals subjected to HS and fed with selenium supplemented diet showed better results regarding gene expression and, thus, better results for the activities of enzymes used as stress markers, which could be due to the higher antioxidant capacity provided by the action of the studied genes. 相似文献