Assay conditions and validation of a new UV spectrophotometric method using microplates for the determination of polyphenol content     

Iigo Uriarte Pueyo  María Isabel Calvo 《Fitoterapia》2009,80(8):465-467

A new spectrophotometric assay for the quantification of polyphenolic content has been validated. It is based on Prussian Blue method and adapted to microplate spectrophotometry. Prussian Blue reaction is critically dependent on reaction time, but microplate spectrophotometry permits exact measures of many samples at the same time. This new method is precise, reproducible, repeatable and exact.  相似文献   

How much do Irish Private Forest Owners Know about Forestry?     

Áine Ní Dhubháin  Rory Greene 《Small-Scale Forestry》2009,8(3):249-262

Since 1980, over 20,000 Irish landowners have afforested land, for the first time, as part of an afforestation programme subsidised by the Government and the EU. A survey of 99 private forest owners was conducted to determine their knowledge of broad aspects of forest management. Key questions were scored so as to test whether respondents had passed or failed a forestry knowledge test. Over two-thirds of private forest owners passed the test. Success in this test was shown to be related to whether respondents had (a) attended extension field days; (b) been active in forest operations in the early stages of the forest cycle and (c) been members of farming and/or forestry groups. Younger respondents (i.e., ≤50 years) were more likely to pass the knowledge test than older respondents.  相似文献   

Incorporating Sectoral Structure into Shift–Share Analysis     

MIGUEL A. MÁRQUEZ  JULIÁN RAMAJO  GEOFFREY J. D. HEWINGS 《Growth and change》2009,40(4):594-618

The objective of this article is to present a new way to incorporate the sectoral dimension within the components of regional growth provided by the traditional shift–share analysis. The new methodology elaborates the way that the dynamics of a specific sector in a region are influenced by the performance of other sectors, the latter decomposed between national, structural, and differential effects. To illustrate this extension of the shift–share method, an application is provided using data for the Spanish region of Extremadura for the period 1990–2004. The results highlight how these new components can shed new insights into the analysis of sectoral and regional economic growth processes.  相似文献   

Antihyperlipidemic Effect of Methanolic Extract from Opuntia joconostle Seeds in Mice Fed a Hypercholesterolemic Diet     

Obed Osorio-Esquivel  Alicia Ortiz-Moreno  Leticia Garduño-Siciliano  Valente B. Álvarez  María Dolores Hernández-Navarro 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(4):365-370

The purpose of this study was to evaluate the hypolipidemic effect of a methanolic extract from Opuntia joconostle seeds fed to mice in a hypercholesterolemic diet. Acute toxicity of the methanolic extract was investigated by an established method. Phenolic composition and antioxidant activity were determined by high-performance liquid chromatography and DPPH, respectively. The total phenolic content of Opuntia joconostle seeds was 47.85?±?1.29 mg gallic acid equivalents/g dry weight. The main phenolic compounds were identified as quercetin, rutin, and cafeic acid. Percent inhibition of DPPH⁺ was 49.76?±?0.49 %. The oral LD₅₀ for the methanolic extract from the Opuntia joconostle seeds was >5,000 mg/kg BW. Mice fed a hypercholesterolemic diet for six days exhibited significantly (P?≤?0.001) higher plasma lipid levels than mice fed a normal diet. Remarkably, supplementation with methanolic extract from Opuntia joconostle at doses of 1, 2, and 5 g/kg body weight significantly (P?≤?0.001) prevented the increase in total cholesterol, low-density lipoprotein cholesterol, triglycerides level, and atherogenic index. Similar concentrations of the HDL cholesterol were observed in both treated and control groups. A significant dose-dependent reduction in lipid levels was noted for treated groups compared to the hypercholesterolemic group. We attribute this result to the seeds’ phenolic composition. This methanolic extract has potential to be included in short-term hypercholesterolemia treatment regimens as it exhibits hypolipidemic activity with no apparent toxic manifestations.  相似文献   

Effects of different bronopol treatments on final survival rates in the artificial incubation of crayfish eggs (Pacifastacus leniusculus,Astacidae)     

Álvaro González  Jesús D. Celada  Pedro M. Melendre  José M. Carral  María Sáez‐Royuela  Rocío González  Vanesa García 《Aquaculture Research》2013,44(3):354-358

Two experiments were conducted on the effects of bronopol in the artificial incubation of crayfish eggs (Pacifastacus leniusculus) with the aim to search an alternative to formaldehyde. In the first experiment, 50, 250, 500 and 1000 ppm bronopol and 3000 ppm formaldehyde (control) in periodical administrations were tested on a density of 6.6 eggs cm^?2. After 44 days of incubation, the highest survival was obtained with 1000 ppm bronopol (81.9% to stage 2 juvenile, with no significant difference from formaldehyde), whereas lower bronopol concentrations resulted in significantly lower survival. In the second experiment, 1000, 3000 and 5000 ppm bronopol and 3000 ppm formaldehyde (control) administered for 15 min every second day were tested on eggs at a density of 20 eggs cm^?2. After 78 days of incubation, bronopol at 3000 ppm allowed for a stage 2 juvenile survival rate of 65.0% (with no significant difference from formaldehyde), whereas significantly lower survival was obtained with 1000 ppm or 5000 ppm. This study shows that bronopol may constitute an alternative to formaldehyde in the artificial incubation of crayfish eggs. A concentration of 3000 ppm administered for 15 min every second day may be adequate even on long incubations at high densities (at least 20 eggs cm^?2, one complete layer).  相似文献   

Model‐based assessment of local‐scale fish larval connectivity in a network of marine protected areas     

GOTZON BASTERRETXEA  ANTONI JORDI  IGNACIO A. CATALÁN  ANA SABATÉS 《Fisheries Oceanography》2012,21(4):291-306

We assessed by numerical modeling the coastal fish larval dispersion along the southern coast of Mallorca (Balearic Islands, NW Mediterranean) with the objective of determining the factors that contribute to successful recruitment. We assumed that fish larvae dispersal is mainly regulated by physical transport. Currents are mainly wind driven in this area; therefore, changes in wind forcing have a first‐order impact on larval transport. The synoptic wind patterns were systematically analyzed based on self‐organizing map analysis. The wind fields were clustered using a neural network pattern recognition approach into two modes, producing opposite along‐shelf flow. The seasonal changes between spring and summer in the dominance of either mode modulate the along‐shelf circulation, producing flow shifts under some circumstances. This variability in the wind regime was consistent throughout the 10 years analyzed (2000–2009). Using the Princeton Ocean Model (POM) and a particle‐tracking algorithm, we analyzed the effect of wind‐forced currents in the connectivity among near‐shore habitats. We show that, at the spatial scale considered, the coastal morphology and stochastic wind forcing favor local recruitment (mean of 30% self‐recruitment). Maximum transport distances of 20–30 km were typically associated with particles left to drift for 21 days. The implications for the performance of the four marine protected areas near SW Mallorca Island are discussed. Our results suggest that, although wind episodes determine the fate of short‐time spawning events, on a seasonal basis, regular larval supply to coastal zones is ensured by wind stochasticity.  相似文献   

Soil Fertility Improvement by Litter Decomposition and Inoculation with the Fungus Mortierella sp. in Avocado Plantations of Colombia     

Álvaro Tamayo-Vélez 《Communications in Soil Science and Plant Analysis》2018,49(2):139-147

Litter decomposition is a major process in nutrient recycling, despite that few studies have considered this in soil fertility management. The aim of this study was to evaluate the effect of litter decomposition and its inoculation with the fungus Mortierella sp. on soil fertility parameters in Andisols cultivated with avocado cv. Hass. Litterbags containing avocado leaves either uninoculated or inoculated were distributed around the trees. As control litter was not allowed to accumulate on the soil surface. Eighteen months later soil samples were collected just below uninoculated and inoculated litterbags and control sites. Soil pH, potassium, calcium, phosphorus, magnesium, and boron significantly increased with litter and in some sites the increase was higher with inoculation. By contrast, soil aluminum, iron, and manganese were significantly lower in the presence of litter (uninoculated and inoculated), whereas zinc was significantly higher when litter was present.  相似文献   

A comparison of indexes to estimate corn S uptake and S mineralization in the field     

Walter?D.?CarciochiEmail author  Nicolás?Wyngaard  Guillermo?A.?Divito  Miguel?L.?Cabrera  Nahuel?I.?Reussi Calvo  Hernán?E.?Echeverría 《Biology and Fertility of Soils》2018,54(3):349-362

The development of simple predictors of sulfur (S) mineralization and its correlation with field-derived data may help improving corn S availability diagnosis. The objectives of this study were (1) to compare methods to estimate soil S mineralization, (2) to develop a model to predict soil S mineralization from S mineralization indexes and edaphic variables, and (3) to predict field-grown corn S uptake (S_uptake) and apparent S mineralization (S_min-app) from different S mineralization indexes and edaphic-climatic variables. We evaluated 26 experimental sites where we measured edaphic variables as soil organic C (SOC), organic C in the particulate fraction (C-PF), S mineralization potential (S_min-10wk), S mineralized during a short-term (7 days) aerobic incubation + initial inorganic S (S_min-7d?+?S_inorg), and N mineralized during a short-term (7 days) anaerobic incubation (N_an). Additionally, 18 field experiments were carried out to quantify S_uptake and S_min-app. The C-PF, S_min-7d?+?S_inorg, N_an, and SOC were variables significantly correlated with S_min-10wk (r?=?0.89, 0.89, 0.88, and 0.85, respectively). We developed a simple model to predict S_min-10wk from selected edaphic variables (S_min-10wk?=?0.038*N_an?+?0.106*SOC?+?0.74; R_a² =?0.87). The S_min-10wk, C-PF, and S_min-7d?+?S_inorg showed a liner-plateau association with S_uptake (R²?=?0.73, 0.53, and 0.48, respectively). We modified the method to estimate S_min-app to account for S losses (S_{min-app (modified)}) and developed a model to predict S_{min-app (modified)} from C-PF (S_{min-app (modified)}?=?4.65*C-PF?+?9.86; R²?=?0.62) or S_min-10wk (S_{min-app (modified)}?=?3.0*S_min-10wk?+?7.4; R²?=?0.54). Our results demonstrate that S mineralization indexes can be used to predict corn S availability under field conditions.  相似文献   

Effect of provision of apiaceous flowers associated to foods on the biology of <Emphasis Type="Italic">Coleomegilla maculata</Emphasis>     

Vinicius de Abreu D’Ávila  Elen de Lima Aguiar-Menezes  Renato Nunes Pereira  Vânia Gonçalves-Esteves  Cláudia Barbieri Ferreira Mendonça  Saulo José de Melo  Tamires Medeiros dos Santos 《Phytoparasitica》2017,45(4):471-484

Coleomegilla maculata DeGeer is an omnivorous lady beetle that feeds on natural or alternative prey and artificial foods, which allows its laboratory rearing for use on augmentative biocontrol. In addition, C. maculata may supplement its diet with pollen and nectar, which helps in its conservation in agroecosystems. This study aimed to evaluate if Apiaceous flowers (Anethum graveolens L. and Coriadrum sativum L.), with and without alternative prey [eggs of Ephestia kuehniella (Zeller) or larvae of Drosophila melanogaster Meigen] or an artificial food (aqueous solution of honey), may guarantee the survival and complete development of the immature and adult stages of C. maculata in the laboratory. The immature stages developed only when Apiaceous flowers were offered with E. kuehniella eggs. The food with only one of the alternative prey (moth eggs or fly larvae) or moth eggs + honey solution resulted in fertile adults; however, the number of eggs/cluster was greater for the foods with E. kuehniella eggs + honey solution, A. graveolens flowers, or only D. melanogaster. Foods comprising only the two Apiaceous species, only the honey solution, or only water resulted in larval development up to a specific instar. Adults of C. maculata also survived on these foods, but there was no oviposition. The foods of the two Apiaceous species produced heavier adults only when associated with E. kuehniella eggs. The results indicate that the zoophytophagous habit of C. maculata should be considered in conservation biocontrol programs aimed at using this lady beetle to control crop pests.  相似文献   

Behaviour of bentazon as influenced by water and tillage management in rice‐growing conditions          下载免费PDF全文

Antonio López‐Piñeiro  David Peña  Ángel Albarrán  Javier Sánchez‐Llerena  José Manuel Rato‐Nunes  María Ángeles Rozas 《Pest management science》2017,73(6):1067-1075

Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice‐growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no‐tillage and sprinkler irrigation (NTS) and long‐term no‐tillage and sprinkler irrigation (NTS7). After 3 years, the K_d values in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half‐life DT₅₀ = 94.1–135 days) than under aerobic (DT₅₀ = 42.4–91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid‐ and long‐term implementation of sprinkler irrigation in combination with no‐tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice‐growing agroecosystems. © 2017 Society of Chemical Industry  相似文献