A new multistage dynamic model for biological control exemplified by the host–parasitoid system <Emphasis Type="Italic">Spodoptera exigua</Emphasis>–<Emphasis Type="Italic">Chelonus oculator</Emphasis>     

József Garay  Zoltán Sebestyén  Zoltán Varga  Manuel Gámez  Alejandro Torres  José E. Belda  Tomás Cabello 《Journal of pest science》2015,88(2):343-358

Over the last few decades, important advances have been made in understanding of host–parasitoid relations and their applications to biological pest control. Not only has the number of agent species increased, but new manipulation techniques for natural enemies have also been empirically introduced, particularly in greenhouse crops. This makes biocontrol more complex, requiring a new mathematical modeling approach appropriate for the optimization of the release of agents. The present paper aimed at filling this gap by the development of a temperature- and stage-dependent dynamic mathematical model of the host–parasitoid system with an improved functional response. The model is appropriate not only for simulation analysis of the efficiency of biocontrol agents, but also for the application of optimal control methodology for the optimal timing of agent releases, and for the consideration of economic implications. Based on both laboratory and greenhouse trials, the model was validated and fitted to the data of Chelonus oculator (F.) (Hym.: Braconidae) as a biological control agent against the beet armyworm, Spodoptera exigua Hübner (Lep.: Noctuidae). We emphasize that this model can be easily adapted to other interacting species involved in biological or integrated pest control with either parasitoid or predator agents.  相似文献   

Effects of two different anesthetic protocols on 64‐MDCT coronary angiography in dogs          下载免费PDF全文

Randi Drees  Rebecca A. Johnson  Marie Pinkerton  Alejandro Munoz Del Rio  Jimmy H. Saunders  Christopher J. François 《Veterinary radiology & ultrasound》2015,56(1):46-54

Heart rate is a major factor influencing diagnostic image quality in computed tomographic coronary artery angiography (MDCT‐CA), with an ideal heart rate of 60–65 beats/min in humans. The purpose of this prospective study was to compare effects of two different clinically applicable anesthetic protocols on cardiovascular parameters and 64‐MDCT‐CA quality in 10 healthy dogs. Scan protocols and bolus volumes were standardized. Image evaluations were performed in random order by a board‐certified veterinary radiologist who was unaware of anesthetic protocols used. Heart rate during image acquisition did not differ between protocols (P = 1), with 80.6 ± 7.5 bpm for protocol A and 79.2 ± 14.2 bpm for protocol B. Mean blood pressure was significantly higher (P > 0.05) using protocol B (protocol A 62.9 ± 9.1 vs. protocol B 72.4 ± 15.9 mmHg). The R‐R intervals allowing for best depiction of individual coronary artery segments were found in the end diastolic period and varied between the 70% and 95% interval. Diagnostic quality was rated excellent, good, and moderate in the majority of the segments evaluated, with higher scores given for more proximal segments and lower for more distal segments, respectively. Blur was the most commonly observed artifact and mainly affected the distal segments. No significant differences were identified between the two protocols for optimal reconstruction interval, diagnostic quality and measured length individual segments, or proximal diameter of the coronary arteries (P = 1). Findings indicated that, when used with a standardized bolus volume, both of these anesthetic protocols yielded diagnostic quality coronary 64‐MDCT‐CA exams in healthy dogs.  相似文献   

Characterization of protein fractions from Bt-transgenic and non-transgenic maize varieties using perfusion and monolithic RP-HPLC. Maize differentiation by multivariate analysis     

Rodríguez-Nogales JM  Cifuentes A  García MC  Marina ML 《Journal of agricultural and food chemistry》2007,55(10):3835-3842

Protein fractions from transgenic Bt and non-transgenic maize varieties, extracted by the Osborne solvent fraction procedure, were characterized for the first time by perfusion and monolithic RP-HPLC in very short analysis times. Albumins and globulins from different transgenic Bt maizes as well as from their non-transgenic isogenic varieties were eluted in four peaks using perfusion RP-HPLC, whereas prolamins and glutelins were separated in seven peaks. Monolithic RP-HPLC enabled the separation of maize proteins in a large number of peaks showing 6 and 10 main peaks for albumins and globulins, respectively. Prolamins migrated at retention times higher than 5 min as seven peaks, whereas glutelins were separated in three main peaks appearing at retention times higher than 6.0 min. Moreover, chromatograms of the whole protein extracts showed 8 and 11 components for perfusion and monolithic RP-HPLC, respectively. A comparison of the chromatograms of the whole protein extracts relative to transgenic and non-transgenic varieties evidenced quantitative differences on the percentages of area, mainly for peaks 2 and 3 by perfusion RP-HPLC and for peaks 3 and 7 by monolithic RP-HPLC. A discriminant analysis based on these proteic profiles was carried out to classify and predict transgenic Bt maize lines, achieving 100% correct classification using perfusion RP-HPLC.  相似文献   

Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement     

Jaime L  Mendiola JA  Ibáñez E  Martin-Alvarez PJ  Cifuentes A  Reglero G  Señoráns FJ 《Journal of agricultural and food chemistry》2007,55(26):10585-10590

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.  相似文献   

Implications of landscape configuration on understory forage productivity: a remote sensing assessment of native forests openings     

Trinco  Fabio Daniel  Rusch  Verónica Elena  Howison  Ruth Alison  Garibaldi  Lucas Alejandro  Tittonell  Pablo Adrián 《Agroforestry Systems》2021,95(8):1675-1688

Agroforestry Systems - Sound management of native forests used for cattle grazing requires understanding the dynamics of forage productivity in the openings. Despite their importance, forage...  相似文献   

Vegetative propagation of the carrageenophytic red alga Gigartina skottsbergii Setchell et Gardner: Indoor and field experiments     

María C. Hernández-González  Alejandro H. Buschmann  Juan A. Correa 《Aquaculture (Amsterdam, Netherlands)》2007,262(1):120-128

The carrageenophytic red alga Gigartina skottsbergii presents several biological constraints for its cultivation such as restricted temporal availability and high spore mortalities that affect the development of its mass cultivation. For this reason, research to develop alternative propagation methods has been undertaken. Previous laboratory studies demonstrated that manipulating temperature, light and nutrients could enhance healing and regeneration of this seaweed. In this study nursery and field experiments were undertaken to establish the possibility to regrow G. skottsbergii in conditions similar to those applied in mass cultivation practices. Frond fragments and rhizoids were tested as alternative ways to obtain new plants. Our results indicate that regeneration occurs in the field, and can be managed in nursery conditions. The addition of a nitrogen source enhances the growth from 0.6 to 1.0% d^− 1 of the healed fragments and the use of a photon flux density above 50 μmol m^− 2 s^− 1 increases the growth rate but decrease the survival of the explants. Explants can be transferred to field conditions and grow at similar rates to those registered in the nursery (0.5% d^− 1). It is also possible to propagate rhizoids of G. skottsbergii and it seems that the attachment of a frond portion to the substratum, enhanced its survival and regeneration capacity. Finally, this study demonstrated that rhizoids attached to rocks can regenerate complete plants in nature, a feature which could be a useful for developing a sustainable harvesting methodology.  相似文献   

Environmental sex determination, external sex differentiation and structure of the androgenic gland in the Pacific white shrimp Litopenaeus vannamei (Boone)     

Rafael Campos-Ramos  Rodolfo Garza-Torres  Danitzia A Guerrero-Tortolero  Alejandro M Maeda-Martínez  & Hortencia Obregón-Barboza 《Aquaculture Research》2006,37(15):1583-1593

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Comparative study of the mechanical properties of polyester resin with and without reinforcement with fiber-glass and furcraea cabuya fibers     

Alejandro Brenes-Acosta  Benito A. Stradi-Granados 《Fibers and Polymers》2014,15(10):2186-2192

A commercially available polyester resin was reinforced with cabuya fibers. The experimental variables were the fiber loading and the length of the fiber. Tensile strength, flexural strength, and the Izod impact resistance were measured for the samples and compared to the polyester resin performance without reinforcement. Mechanical properties of the cabuya fiber reinforced material were also compared with the same resin but reinforced with glass fibers. An increase in fiber load decreases the tensile strength for the cabuya reinforced composite, where a value of 52.6 MPa corresponded to the tensile stress of the resin without reinforcement and a value of 34.5 MPa for the best reinforcement achieved with cabuya. An increase in both fiber load and length increases the Young’s modulus of the cabuya reinforced material, and a maximum value of 2885 MPa was obtained. The Young’s modulus and impact resistance values for the cabuya composite (2885 MPa and 100.87 J/m, respectively) reached higher values than those obtained for non-reinforced polyester material (2639 MPa and 5.82 J/m, respectively), and lower than the glass fiber composite (5526 MPa and 207.46 J/m, respectively); while the tensile and flexural strength obtained for the cabuya composite (34.5 MPa and 32.6 MPa, respectively) were lower than the unreinforced (52.6 MPa and 62.9 MPa, respectively) and glass fiber reinforced polyester (87.3 MPa and 155 MPa, respectively).  相似文献   

New invasive predator reduces the abundance of native prey in a cold-temperate marine fouling community     

Nicolás Battini  Clara B. Giachetti  Karen L. Castro  Alejandro Bortolus  Evangelina Schwindt 《水产资源保护:海洋与淡水生态系统》2021,31(10):2842-2854

1. Invasive species threaten the conservation of marine environments, and urgent management strategies are needed to prevent their introduction, establishment and spread. Specifically, marine invasive predators destabilize ecological interactions and alter community structure and function. However, most of the evidence showing the effect of these predators is restricted to a few species and regions, while for others the information remains scarce.
2. This study experimentally evaluated the ecological effects of the sea slug Pleurobranchaea maculata, a recently introduced invasive predator, on the fouling communities of a cold-temperate port in the South-western Atlantic.
3. The results show that increasing predation pressure reduces significantly the abundance of sea anemones, which are among the preferred prey items.
4. This study reveals new evidence to help better understand the effects of P. maculata on the biological communities of a recently invaded region. Furthermore, it provides the first experimental evidence supporting the hypothesis that marine invasive predators can induce a significant decrease in the abundance of native species in benthic communities of cold-temperate marine environments in the South-western Atlantic.

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Formation of Amadori compounds in dehydrated fruits.     

M L Sanz  M D del Castillo  N Corzo  A Olano 《Journal of agricultural and food chemistry》2001,49(11):5228-5231

The presence of Amadori compounds in commercial dehydrated fruits has been shown through HPLC analysis of the corresponding 2-furoylmethyl-amino acids obtained by acid hydrolysis. Furosine (2-furoylmethyl-lysine) was the main 2-furoylmethyl derivative observed in dried figs and apricot samples, whereas in prunes and dates similar amounts of furosine and 2-furoylmethyl-gamma-aminobutyric acid were detected. A considerable variation of 2-furoylmethyl-amino acid contents among commercial raisin samples was observed. 2-Furoylmethyl-gamma-aminobutyric acid and 2-furoylmethyl-arginine, the most abundant 2-furoylmethyl-amino acids, ranged between 9.9 and 75.8 mg/100 g sample and 10.0 and 62.5 mg/100 g sample, respectively. Most of the Amadori compounds present in raisins seem to have originated during the commercial shelf life period rather than during processing. Determination of 2-furoylmethyl-amino acids could be used as a method of controlling commercial dehydrated fruit and selecting storage conditions.  相似文献