647 research outputs found

    Assays with Commercially Produced Trichogramma (Hymenoptera: Trichogrammatidae) To Determine Suitability for Obliquebanded Leafroller (Lepidoptera: Tortricidae) Control

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    Laboratory assays were used to compare the ability of commercially produced Trichogramma spp. to parasitize eggs of the obliquebanded leafroller, Choristoneura rosaceana (Harris), in the laboratory and field. Trichogramma platneri Nagarkatti parasitized more obliquebanded leafroller eggs per egg mass than did Trichogramma pretiosum Riley or Trichogramma minutum Riley produced by either of 2 insectaries. T. minutum produced at 1 insectary caused significantly more host mortality by host feeding and repiercing than by parasitism. Variation in parasitoid performance from different insectaries and among shipments from the same insectary was common. Young egg masses were more heavily parasitized than old egg masses. Parasitism increased as the number of conspecific female Trichogramma spp. placed on the same host increased, but the number of eggs parasitized per female decreased. Exposure of host egg masses to female Trichogramma spp. prevented additional oviposition in the same egg mass by conspecific, ovipositionally experienced females but had no effect on parasitism by conspecific, ovipositionally naive females. The method used to attach sentinel egg masses to foliage influenced parasitism rates. Moistening the leaf with water and adhering the egg mass to the moistened leaf had the least impact. Inundative releases of Trichogramma spp. into an apple orchard paralleled laboratory assays by showing greater parasitism of obliquebanded leafroller egg masses by T. platneri than with T. minutum. However, extreme differences observed in field performance between the 2 species was not predicted from the assay

    The [4+2]‐Cycloaddition of α‐Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero‐Diels–Alder Reactions—Experimental and Computational Studies

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    The [4+2]‐cycloadditions of α‐nitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styryl‐substituted 4H‐1,5,2‐oxathiazines in moderate to good yields. Of the eight conceivable hetero‐Diels–Alder adducts only this isomer was observed, thus a prototype of a highly periselective and regioselective cycloaddition has been identified. Analysis of crude product mixtures revealed that the α‐nitrosoalkene also adds competitively to the thioketone moiety of the thiochalcone dimer affording bis‐heterocyclic [4+2]‐cycloadducts. The experiments are supported by high‐level DFT calculations that were also extended to related hetero‐Diels–Alder reactions of other nitroso compounds and thioketones. These calculations reveal that the title cycloadditions are kinetically controlled processes confirming the role of thioketones as superdienophiles. The computational study was also applied to the experimentally studied thiochalcone dimerization, and showed that the 1,2‐dithiin and 2H‐thiopyran isomers are in equilibrium with the monomer. Again, the DFT calculations indicate kinetic control of this process

    Interference with the Mate-Finding Communication System of the Obliquebanded Leafroller (Lepidoptera: Tortricidae) Using Synthetic Sex Pheromones

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    Effect of atmospheric permeation with synthetic sex pheromone on the behavior and control of obliquebanded leafroller, Choristoneura rosaceana (Harris), was studied in small and large plots in commercial apple orchards. Synthetic sex pheromone significantly reduced the ability of male moths to locate pheromone-baited traps and tethered females; however, no differences were found among 3 pheromone rates. Location of pheromone dispensers within the tree canopy did not alter the number of males locating pheromone-baited traps and mating tethered females. Obliquebanded leafroller activity was greatest in the upper positions of the tree canopy and no edge effect was observed around perimeters of large disrupted blocks. The presence of gravid feral females, mated tethered females, high larval densities, and fruit damage within large pheromone disrupted blocks indicate obliqubanded leafrollers mate in orchards treated with synthetic sex pheromone. However, fruit damage caused by obliquebanded leafroller larvae was similar in pheromone, pheromone plus insecticide, and insecticide treatment

    Lazy Abstraction-Based Controller Synthesis

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    We present lazy abstraction-based controller synthesis (ABCS) for continuous-time nonlinear dynamical systems against reach-avoid and safety specifications. State-of-the-art multi-layered ABCS pre-computes multiple finite-state abstractions of varying granularity and applies reactive synthesis to the coarsest abstraction whenever feasible, but adaptively considers finer abstractions when necessary. Lazy ABCS improves this technique by constructing abstractions on demand. Our insight is that the abstract transition relation only needs to be locally computed for a small set of frontier states at the precision currently required by the synthesis algorithm. We show that lazy ABCS can significantly outperform previous multi-layered ABCS algorithms: on standard benchmarks, lazy ABCS is more than 4 times faster

    Global generalized solutions for Maxwell-alpha and Euler-alpha equations

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    We study initial-boundary value problems for the Lagrangian averaged alpha models for the equations of motion for the corotational Maxwell and inviscid fluids in 2D and 3D. We show existence of (global in time) dissipative solutions to these problems. We also discuss the idea of dissipative solution in an abstract Hilbert space framework.Comment: 27 pages, to appear in Nonlinearit

    Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome

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    <p>Abstract</p> <p>Background</p> <p>Differential diagnosis between acute cardiogenic pulmonary edema (APE) and acute lung injury/acute respiratory distress syndrome (ALI/ARDS) may often be difficult. We evaluated the ability of chest sonography in the identification of characteristic pleuropulmonary signs useful in the diagnosis of ALI/ARDS and APE.</p> <p>Methods</p> <p>Chest sonography was performed on admission to the intensive care unit in 58 consecutive patients affected by ALI/ARDS or by acute pulmonary edema (APE).</p> <p>Results</p> <p>Ultrasound examination was focalised on finding in the two groups the presence of: 1) alveolar-interstitial syndrome (AIS) 2) pleural lines abnormalities 3) absence or reduction of "gliding" sign 4) "spared areas" 5) consolidations 6) pleural effusion 7) "lung pulse".</p> <p>AIS was found in 100% of patients with ALI/ARDS and in 100% of patients with APE (p = ns). Pleural line abnormalities were observed in 100% of patients with ALI/ARDS and in 25% of patients with APE (p < 0.0001). Absence or reduction of the 'gliding sign' was observed in 100% of patients with ALI/ARDS and in 0% of patients with APE. 'Spared areas' were observed in 100% of patients with ALI/ARDS and in 0% of patients with APE (p < 0.0001). Consolidations were present in 83.3% of patients with ALI/ARDS in 0% of patients with APE (p < 0.0001). A pleural effusion was present in 66.6% of patients with ALI/ARDS and in 95% of patients with APE (p < 0.004). 'Lung pulse' was observed in 50% of patients with ALI/ARDS and in 0% of patients with APE (p < 0.0001).</p> <p>All signs, except the presence of AIS, presented a statistically significant difference in presentation between the two syndromes resulting specific for the ultrasonographic characterization of ALI/ARDS.</p> <p>Conclusion</p> <p>Pleuroparenchimal patterns in ALI/ARDS do find a characterization through ultrasonographic lung scan. In the critically ill the ultrasound demonstration of a dyshomogeneous AIS with spared areas, pleural line modifications and lung consolidations is strongly predictive, in an early phase, of non-cardiogenic pulmonary edema.</p

    Tobacco\u27s Minor Alkaloids: Effects on Place Conditioning and Nucleus Accumbens Dopamine Release in Adult and Adolescent Rats

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    Tobacco products are some of the most commonly used psychoactive drugs worldwide. Besides nicotine, alkaloids in tobacco include cotinine, myosmine, and anatabine. Scientific investigation of these constituents and their contribution to tobacco dependence is less well developed than for nicotine. The present study evaluated the nucleus accumbens dopamine-releasing properties and rewarding and/or aversive properties of nicotine (0.2-0.8 mg/kg), cotinine (0.5-5.0 mg/kg), anatabine (0.5-5.0 mg/kg), and myosmine (5.0-20.0 mg/kg) through in vivo microdialysis and place conditioning, respectively, in adult and adolescent male rats. Nicotine increased dopamine release at both ages, and anatabine and myosmine increased dopamine release in adults, but not adolescents. The dopamine release results were not related to place conditioning, as nicotine and cotinine had no effect on place conditioning, whereas anatabine and myosmine produced aversion in both ages. While the nucleus accumbens shell is hypothesized to play a role in strengthening drug-context associations following initiation of drug use, it may have little involvement in the motivational effects of tobacco constituents once these associations have been acquired. Effects of myosmine and anatabine on dopamine release may require a fully developed dopamine system, since no effects of these tobacco alkaloids were observed during adolescence. In summary, while anatabine and myosmine-induced dopamine release in nucleus accumbens may play a role in tobacco dependence in adults, the nature of that role remains to be elucidated

    Fruit herbivory alters plant electrome: evidence for fruit-shoot long-distance electrical signaling in tomato plants.

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    The electrical activity of tomato plants subjected to fruit herbivory was investigated. The study aimed to test the hypothesis that tomato fruits transmit long-distance electrical signals to the shoot when subjected to herbivory. For such, time series classification by machine learning techniques and analyses related to the oxidative response were employed. Tomato plants (cv. ?Micro-Tom?) were placed into a Faraday?s cage and an electrode pair was inserted in the fruit?s peduncle. Helicoverpa armigera caterpillars were placed on the fruit (either green and ripe) for 24 h. The time series were recorded before and after the fruit?s exposure of the caterpillars. The plant material for chemical analyses was collected 24 and 48 h after the end of the acquisition of electrophysiological data. The time series were analyzed by the following techniques: Fast Fourier Transform (FFT), Wavelet Transform, Power Spectral Density (PSD), and Approximate Entropy. The following features from FFT, PSD, and Wavelet Transform were used for PCA (Principal Component Analysis): average, maximum and minimum value, variance, skewness, and kurtosis. Additionally, these features were used in Machine Learning (ML) analyses for looking for classifiable patterns between tomato plants before and after fruit herbivory. Also, we compared the electrome before and after herbivory in the green and ripe fruits. To evaluate an oxidative response in different organs, hydrogen peroxide, superoxide anion, catalase, ascorbate peroxidase, guaiacol peroxidase, and superoxide dismutase activity were evaluated in fruit and leaves. The results show with 90% of accuracy that the electrome registered in the fruit?s peduncle before herbivory is different from the electrome during predation on the fruits. Interestingly, there was also a sharp difference in the electrome of the green and ripe fruits? peduncles before, but not during, the herbivory, which demonstrates that the signals generated by the herbivory stand over the others. Biochemical analysis showed that herbivory in the fruit triggered an oxidative response in other parts of the plant. Here, we demonstrate that the fruit perceives biotic stimuli and transmits electrical signals to the shoot of tomato plants. This study raises new possibilities for studies involving electrical signals in signaling and systemic response, as well as for the applicability of ML to classify electrophysiological data and its use in early diagnosis
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