Is emamectin benzoate effective against the different stages of Spodoptera exigua (Hübner) (Lepidoptera, Noctuidae)?

peer-reviewedThis work was partially supported by the Spanish Ministry of Science and Innovation (project AGL 2007-66130-C03-02 to P. Medina). F. Amor and P. Bengochea acknowledge the ministry of Education and Culture and the Technical University of Madrid (UPM) for the doctoral fellowships. Special thanks to Syngenta Agro S.A. for their support.The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera, Noctuidae), is a major polyphagous pest in greenhouses and open fields worldwide and also a main problem in sweet pepper greenhouses. The effectiveness of the pesticide emamectin benzoate was tested in the laboratory on different stages of S. exigua using different concentrations and uptake routes. After dipping young (48-h-old) S. exigua eggs in emamectin benzoate at 0.5, 1 and 1.5 mg/L a.i. the chemical did not exhibit any ovicidal activity. There was, however, progressive neonate mortality at all concentrations, culminating at 72 hours after hatching, when 100% of the larvae from the treated young eggs died. Second and fourth instar S. exigua larvae did not exhibit significant mortality when exposed to the inert surfaces which were treated. In contrast, ingesting a diet contaminated with 0.5 mg/L a.i. of emamectin benzoate caused 100% mortality in L2 and L4 larvae 24 and 72 hours after ingestion, respectively. The LC50 value of the compound against L4 larvae that fed on sprayed sweet pepper leaves for 24 hours was 0.81 mg/L a.i.. When adults were fed on a solution of 0.5 mg/L a.i., there was a reduction in the female and male lifespan of 29.3% and 55.3%, respectively. Fecundity was reduced by more than 99%. These data suggest that emamectin benzoate is not only a useful insecticide when ingested by beet armyworm larvae but it also has ovolarvicidal and adult activity.Spanish Ministry of Science and Innovatio

Near-Infrared Polarimetric Adaptive Optics Observations of NGC 1068: A torus created by a hydromagnetic outflow wind

We present J' and K' imaging linear polarimetric adaptive optics observations of NGC 1068 using MMT-Pol on the 6.5-m MMT. These observations allow us to study the torus from a magnetohydrodynamical (MHD) framework. In a 0.5" (30 pc) aperture at K', we find that polarisation arising from the passage of radiation from the inner edge of the torus through magnetically aligned dust grains in the clumps is the dominant polarisation mechanism, with an intrinsic polarisation of 7.0%$\pm$2.2%. This result yields a torus magnetic field strength in the range of 4$-$82 mG through paramagnetic alignment, and 139$^{+11}_{-20}$ mG through the Chandrasekhar-Fermi method. The measured position angle (P.A.) of polarisation at K$'$ is found to be similar to the P.A. of the obscuring dusty component at few parsec scales using infrared interferometric techniques. We show that the constant component of the magnetic field is responsible for the alignment of the dust grains, and aligned with the torus axis onto the plane of the sky. Adopting this magnetic field configuration and the physical conditions of the clumps in the MHD outflow wind model, we estimate a mass outflow rate $\le$0.17 M$_{\odot}$ yr$^{-1}$ at 0.4 pc from the central engine for those clumps showing near-infrared dichroism. The models used were able to create the torus in a timescale of $\geq$10$^{5}$ yr with a rotational velocity of $\leq$1228 km s$^{-1}$ at 0.4 pc. We conclude that the evolution, morphology and kinematics of the torus in NGC 1068 can be explained within a MHD framework.Comment: 14 pages, 4 figures, Accepted by MNRA

On the difference of torus geometry between hidden and non-hidden broad line active galactic nuclei

We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGN) with clumpy torus models. We compiled high spatial resolution ($\sim 0.3$--$0.7$ arcsec) mid-IR $N$-band spectroscopy, $Q$-band imaging and nuclear near- and mid-IR photometry from the literature. Combining these nuclear near- and mid-IR observations, far-IR photometry and clumpy torus models, enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus model parameters gives us the first quantitative torus geometrical view for each subgroup. We find that NHBLR AGN have smaller torus opening angles and larger covering factors than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small torus opening angle and (b) the increased torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGN.Comment: 13 pages, 5 figures, accepted for publication in Ap

Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

We present sub-arcsecond 7.5$-$13 $\mu$m imaging- and spectro-polarimetric observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio CANARIAS. At all wavelengths, we find: (1) A 90 $\times$ 60 pc extended polarized feature in the northern ionization cone, with a uniform $\sim$44$^{\circ}$ polarization angle. Its polarization arises from dust and gas emission in the ionization cone, heated by the active nucleus and jet, and further extinguished by aligned dust grains in the host galaxy. The polarization spectrum of the jet-molecular cloud interaction at $\sim$24 pc from the core is highly polarized, and does not show a silicate feature, suggesting that the dust grains are different from those in the interstellar medium. (2) A southern polarized feature at $\sim$9.6 pc from the core. Its polarization arises from a dust emission component extinguished by a large concentration of dust in the galaxy disc. We cannot distinguish between dust emission from magnetically aligned dust grains directly heated by the jet close to the core, and aligned dust grains in the dusty obscuring material surrounding the central engine. Silicate-like grains reproduce the polarized dust emission in this feature, suggesting different dust compositions in both ionization cones. (3) An upper limit of polarization degree of 0.3 per cent in the core. Based on our polarization model, the expected polarization of the obscuring dusty material is $\lesssim$0.1 per cent in the 8$-$13 $\mu$m wavelength range. This low polarization may be arising from the passage of radiation through aligned dust grains in the shielded edges of the clumps.Comment: 17 pages, 10 figures, accepted for publication at MNRA

On the solution of a supersymmetric model of correlated electrons

We consider the exact solution of a model of correlated electrons based on the superalgebra $Osp(2|2)$. The corresponding Bethe ansatz equations have an interesting form. We derive an expression for the ground state energy at half filling. We also present the eigenvalue of the transfer matrix commuting with the Hamiltonian.Comment: Palin latex , 8 page

Estimations of the Magnetic Field Strength in the Torus of IC 5063 Using Near-Infrared Polarimetry

An optically and geometrically thick torus obscures the central engine of active galactic nuclei (AGN) from some lines of sight. From a magnetohydrodynamical framework, the torus can be considered to be a particular region of clouds surrounding the central engine where the clouds are dusty and optically thick. In this framework, the magnetic field plays an important role in the creation, morphology and evolution of the torus. If the dust grains within the clouds are assumed to be aligned by paramagnetic alignment, then the ratio of the intrinsic polarization and visual extinction, P(per cent)/Av, is a function of the magnetic field strength. To estimate the visual extinction through the torus and constrain the polarization mechanisms in the nucleus of the type 2 AGN, IC 5063, we developed a polarization model to fit both the total and polarized flux in a 1.2-arcsec (∼263 pc) aperture. The polarization model is consistent with the nuclear polarization observed at Kn (2.0–2.3 μm) being produced by dichroic absorption from aligned dust grains with a visual extinction through the torus of 48 ± 2 mag. We estimated the intrinsic polarization arising from dichroic absorption to be PdicKn=12.5±2.7 per cent. We consider the physical conditions and environment of the gas and dust for the torus of IC 5063. Then, through paramagnetic alignment, we estimate a magnetic field strength in the range of 12–128 mG in the near-infrared emitting regions of the torus of IC 5063. Alternatively, we estimate the magnetic field strength in the plane of the sky using the Chandrasekhar–Fermi method. The minimum magnetic field strength in the plane of the sky is estimated to be 13 and 41 mG depending of the conditions within the torus of IC 5063. These techniques afford the chance to make a survey of AGN, to investigate the effects of magnetic field strength on the torus, accretion and interaction to the host galaxy

Mechano-Optical Analysis of Single Cells with Transparent Microcapillary Resonators

The study of biophysical properties of single cells is becoming increasingly relevant in cell biology and pathology. The measurement and tracking of magnitudes such as cell stiffness, morphology, and mass or refractive index have brought otherwise inaccessible knowledge about cell physiology, as well as innovative methods for high-throughput label-free cell classification. In this work, we present hollow resonator devices based on suspended glass microcapillaries for the simultaneous measurement of single-cell buoyant mass and reflectivity with a throughput of 300 cells/minute. In the experimental methodology presented here, both magnitudes are extracted from the devices' response to a single probe, a focused laser beam that enables simultaneous readout of changes in resonance frequency and reflected optical power of the devices as cells flow within them. Through its application to MCF-7 human breast adenocarcinoma cells and MCF-10A nontumorigenic cells, we demonstrate that this mechano-optical technique can successfully discriminate pathological from healthy cells of the same tissue type