1,908 research outputs found

    A transgenic plant having enhanced drought tolerance

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    The present invention relates to the field of transgenic plants with novel phenotypes, especially plants with enhanced drought and pathogen resistance. Provided are transgenic crop plants comprising integrated in their genome a chimeric gene, characterized by said chimeric gene comprising a transcription regulatory sequence active in plant cells operably linked to a nucleic acid sequence encoding a protein having the sequence of SEQ ID NO: 3 or a protein at least 70 % identical to SEQ ID NO: 3, or an ortholog protein or a functional fragment thereof. In addition to enhanced drought tolerance the transgenic plants may show enhanced disease resistance and enhanced root structure

    Lie theory and separation of variables. 5. The equations iUt + Uxx = 0 and iUt + Uxx −c/x2 U = 0

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    A detailed study of the group of symmetries of the time-dependent free particle Schrödinger equation in one space dimension is presented. An orbit analysis of all first order symmetries is seen to correspond in a well-defined manner to the separation of variables of this equation. The study gives a unified treatment of the harmonic oscillator (both attractive and repulsive), Stark effect, and free particle Hamiltonians in the time dependent formalism. The case of a potential c/x2 is also discussed in the time dependent formalism. Use of representation theory for the symmetry groups permits simple derivation of expansions relating various solutions of the Schrödinger equation, several of which are new

    Ants as predators of the egg parasitoid Trichogramma cacoeciae (Hymenoptera: Trichogrammatidae) applied for biological control of the olive moth, Prays oleae (Lepidoptera: Plutellidae) in Portugal

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    The detrimental effect of predators on Trichogramma cacoeciae March. releases to control the olive moth, Prays oleae Bern., in the TrĂĄs-os-Montes region (Northeast of Portugal), was evaluated during three releases against the flower generation of the pest in 2002. At 1 and 3 h and at 1, 3, 7 and 14 days after each release, 30 Trichogramma releasing cards were examined in the field and predators were collected and identified. Furthermore, at 1, 3, 7 and 14 days after each release, the percentage of egg predation on the cards was also determined. Formicidae were the most abundant group of predators at 99.1% of the total individuals collected. Ten species were identified, Camponotus aethiops, C. lateralis, C. piceus, C. truncatus, Crematogaster auberti, C. scutellaris, Lasius niger, Leptotorax angustulus, Plagiolephis pygmaea and Tapinoma nigerrimum. T. nigerrimum was the most abundant species, both in total numbers as well as in the number of occupied cards. One day after release, the percentage of predation was 24.0% in the first release, 59.4% in the second and 38.0% in the third. Three days after release, the percentage of predation varied from 60.2 to 83.4% during the three release events. Seven days after release, the percentage of predation increased to 97.8% of the total eggs on cards

    Effects of different attractive sources on the abundance of Hymenoptera and possible enhancement of their activity on Prays oleae Bern.

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    Vortex behavior near a spin vacancy in 2D XY-magnets

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    The dynamical behavior of anisotropic two dimensional Heisenberg models is still a matter of controversy. The existence of a central peak at all temperatures and a rich structure of magnon peaks are not yet understood. It seems that the central peaks are related, in some way, to structures like vortices. In order to contribute to the discussion of the dynamical behavior of the model we use Monte Carlo and spin dynamics simulations as well analytical calculations to study the behavior of vortices in the presence of nonmagnetic impurities. Our simulations show that vortices are attracted and trapped by the impurities. Using this result we show that if we suppose that vortices are not very much disturbed by the presence of the impurities, then they work as an attractive potential to the vortices explaining the observed behavior in our simulations.Comment: 4 pages, 6 figure

    Critical Collapse of Cylindrically Symmetric Scalar Field in Four-Dimensional Einstein's Theory of Gravity

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    Four-dimensional cylindrically symmetric spacetimes with homothetic self-similarity are studied in the context of Einstein's Theory of Gravity, and a class of exact solutions to the Einstein-massless scalar field equations is found. Their local and global properties are investigated and found that they represent gravitational collapse of a massless scalar field. In some cases the collapse forms black holes with cylindrical symmetry, while in the other cases it does not. The linear perturbations of these solutions are also studied and given in closed form. From the spectra of the unstable eigen-modes, it is found that there exists one solution that has precisely one unstable mode, which may represent a critical solution, sitting on a boundary that separates two different basins of attraction in the phase space.Comment: Some typos are corrected. The final version to appear in Phys. Rev.

    SonolĂȘncia diurna excessiva em condutores de veĂ­culos pesados

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    Introduction: Excessive daytime sleepiness is an entity that has a negative impact on physical and cognitive performance, since it reduces the individual's ability to respond to stimuli. Professional drivers are undoubtedly a class exposed to this entity, endangering their life and others. Objective: To investigate the prevalence of Excessive Daytime Sleepiness in drivers of heavy trucks and passenger vehicles, comparing it with accidents/near misses accidents and also to relate these variables with the type of vehicle. Methods: This study evaluated 148 drivers, of which 68 were drivers of heavy trucks vehicles, 58 of passenger vehicles and 22 of both types of trucks. Both Epworth Sleepiness Scale and a questionnaire to assess sleeping habits and driving habits were used. Results: The prevalence of sleepiness in drivers is 37,8 % and it was correlated with the total time in bed (r = -0.169, p = 0.040) and with the time of driving of heavy trucks (r = 0.151, p = 0.068). It was found that 14.2 % of accidents and 27.8 % of near misses accidents were due to sleepiness. Highly significant differences in sleepiness and near misses were found (p < 0.001). There was dependence between the type of vehicle and accidents (p = 0.046). Conclusion: In the group of evaluated drivers there is Excessive Daytime Sleepiness, which leads to the significantly increasing risk of accidents/near misses accidents, as well as a higher incidence of accidents in truck drivers compared to drivers of passenger vehicles.info:eu-repo/semantics/publishedVersio

    Analysis of haloacetic acids in water and air (aerosols) from indoor swimming pools using HS-SPME/GC/ECD

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    A solid phase microextraction method was used for the analysis of nine haloacetic acids (HAAs) in water and air (aerosols) from indoor swimming pools (ISPs). The analysis is characterized by derivatization of HAAs to their methyl-esters with dimethyl sulphate, headspace solid phase microextraction (HS-SPME) with a Carboxen–polydimethylsiloxane (CAR-PDMS) fiber and gas chromatography - electron capture detector (GC/ECD). High correlation coefficients were obtained for esters mixture calibration lines and detection limits were found to be at the low ppb level. Repeatability was assessed and coefficients of variation varied from 10 to 20%. Reproducibility was also evaluated and coefficients of variation from 15 to 25% were obtained. Analytical results from four Portuguese ISPs showed that the mean concentration of total HAAs (THAAs) in water ranged from 10 ± 2 to 183 ± 28 ÎŒg/L in which 55 ± 20% corresponded to trichloroacetic and dichloroacetic acids (TCAA and DCAA). THAAs highest concentrations were directly related to higher ISPs’ water organic matter content. In the lack of European specific regulation for water from ISPs and taking into consideration that ingestion is a form of exposure, THAAs concentration values were compared with drinking water maximum contamination level (MCL) of 60 ÎŒg/L proposed by the US EPA for the sum of five HAAs. In 35% of water sampling campaigns the sum of MBAA (monobromoacetic acid), MCAA (monochloroacetic acid), DCAA and TCAA exceeded that MCL value. The concentrations obtained for THAAs in the ISPs’ atmosphere ranged from 5 ± 1 to 64 ± 10 ÎŒg/m3 (T = 28◩C at 5 cm above the water surface) and were proportional to the aerosols’ quantity, which was deeply related to indoor air ventilation system.info:eu-repo/semantics/publishedVersio

    Lattice distortions in a sawtooth chain with Heisenberg and Ising bonds

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    An exactly solvable model of the sawtooth chain with Ising and Heisenberg bonds and with coupling to lattice distortion for Heisenberg bonds is considered in the magnetic field. Using the direct transfer-matrix formalism an exact description of the thermodynamic functions is obtained. The ground state phase diagrams for all regions of parameters values containing phases corresponding to the magnetization plateaus at M=0,1/4M=0,1/4 and 1/2 have been obtained. Exact formulas for bond distortions for various ground states are presented. A novel mechanism of magnetization plateau stabilization corresponding to M=1/4M=1/4 state is reported.Comment: 16 pages, 12 figure
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