345 research outputs found
Life history parameters of Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) at different environmental conditions on two bean cultivars
Life-history parameters of the greenhouse whitefly Trialeurodes vaporariorum (Westwood), an important pest of bean crops in Colombia, were determined in environmental control chambers on two dry bean (Phaseolus vulgaris) cultivars (cv.). Trialeurodes vaporariorum longevity on cv. Chocho decreased as temperature increased from 22.6 d at 19ÂșC to 5.9 d at 26ÂșC. Fecundity was significantly lower at 19ÂșC (8.6 eggs/female), as compared to 22ÂșC (32.6 eggs/female) and 26ÂșC (33.3 eggs/female) on cv. Chocho. Fecundity on cv. ICA-Pijao was much higher (127.2 eggs/female) than on cv. Chocho (32.6 eggs/female) at 19ÂșC. The intrinsic rate of population increase (rm) was highest at 22ÂșC (0.061), intermediate at 19ÂșC (0.044) and lowest at 26ÂșC (0.035) on cv. Chocho, and was 0.072 on cv. ICA-Pijao at 19ÂșC. Life history parameters of T. vaporariorum are compared to those of one of its natural enemies, the parasitoid Amitus fuscipennis MacGown & Nebeker. Finally, data are presented on the distribution of the parasitoid related to the altitude for the Valle del Cauca, Colombi
Imaging Flux Vortices in MgB2 using Transmission Electron Microscopy
We report the successful imaging of flux vortices in single crystal MgB2
using transmission electron microscopy. The specimen was thinned to electron
transparency (350 nm thickness) by focussed ion beam milling. An artefact of
the thinning process was the production of longitudinal thickness undulations
of height 1-2 nm in the sample which acted as pinning sites due to the energy
required for the vortices to cross them. These had a profound effect on the
patterns of vortex order observed which we examine here.
Supplementary information can be downloaded from
http://www-hrem.msm.cam.ac.uk/people/loudon/#publicationsComment: 3 pages, 2 figures to appear in Physica C. Supplementary information
can be downloaded from
http://www-hrem.msm.cam.ac.uk/people/loudon/#publications. The discussion of
the vortex-free region near the sample edge has been revised in response to
referees' comments. Changes have been made to clarify that the specimen
thickness is 250nm parallel to the c-axis but 350nm parallel to the electron
bea
Insight on tricalcium silicate hydration and dissolution mechanism from molecular simulations
Hydration of mineral surfaces, a critical process for many technological applications, encompasses multiple coupled chemical reactions and topological changes, challenging both experimental characterization and computational modeling. In this work, we used reactive force field simulations to understand the surface properties, hydration, and dissolution of a model mineral, tricalcium silicate. We show that the computed static quantities, i.e., surface energies and water adsorption energies, do not provide useful insight into predict mineral hydration because they do not account for major structural changes at the interface when dynamic effects are included. Upon hydration, hydrogen atoms from dissociated water molecules penetrate into the crystal, forming a disordered calcium silicate hydrate layer that is similar for most of the surfaces despite wide-ranging static properties. Furthermore, the dynamic picture of hydration reveals the hidden role of surface topology, which can lead to unexpected water tessellation that stabilizes the surface against dissolution. © 2015 American Chemical Society
Configuration Complexities of Hydrogenic Atoms
The Fisher-Shannon and Cramer-Rao information measures, and the LMC-like or
shape complexity (i.e., the disequilibrium times the Shannon entropic power) of
hydrogenic stationary states are investigated in both position and momentum
spaces. First, it is shown that not only the Fisher information and the
variance (then, the Cramer-Rao measure) but also the disequilibrium associated
to the quantum-mechanical probability density can be explicitly expressed in
terms of the three quantum numbers (n, l, m) of the corresponding state.
Second, the three composite measures mentioned above are analytically,
numerically and physically discussed for both ground and excited states. It is
observed, in particular, that these configuration complexities do not depend on
the nuclear charge Z. Moreover, the Fisher-Shannon measure is shown to
quadratically depend on the principal quantum number n. Finally, sharp upper
bounds to the Fisher-Shannon measure and the shape complexity of a general
hydrogenic orbital are given in terms of the quantum numbers.Comment: 22 pages, 7 figures, accepted i
ERK1/2 is activated in non-small-cell lung cancer and associated with advanced tumours
Activation of the ERK1/2 pathway is involved in malignant transformation both in vitro and in vivo. Little is known about the role of activated ERK1/2 in non-small cell lung cancer (NSCLC). The purpose of this study was to characterise the extent of the activation of ERK1/2 by immunohistochemistry in patients with NSCLC, and to determine the relationship of ERK1/2 activation with clinicopathological variables. Specimens from 111 patients with NSCLC (stages I-IV) were stained for P-ERK. Staining for epidermal growth factor receptor (EGFR) and Ki-67 was also performed. In all, 34% of the tumour specimens showed activation for ERK1/2, while normal lung epithelial tissue was consistently negative. There was a strong statistical correlation between nuclear and cytoplasmic P-ERK staining and advanced stages (P<0.05 and P<0.001, respectively), metastatic hilar or mediastinal lymph nodes (P<0.01, P<0.001), and higher T stages (P<0.01, P<0.001). We did not find correlation of nuclear or cytoplasmic P-ERK staining with either EGFR expression or Ki-67 expression. Total ERK1/2 expression was evaluated with a specific ERK1/2 antibody and showed that P-ERK staining was not due to ERK overexpression but rather to hyperactivation of ERK1/2. Patients with a positive P-ERK cytoplasmic staining had a significant lower survival (P<0.05). However, multivariate analysis did not show significant survival difference. Our study indicates that nuclear and cytoplasmic ERK1/2 activation positively correlates with stage, T and lymph node metastases, and thus, is associated with advanced and aggressive NSCLC tumours
Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound
In thepresentworkitisshownhowgeopolymerscanbeusedtocontrolindoorandoutdoorair pollution byphotolysisof2-ButanoneasaVolatileOrganicCompound(VOC).Anionexchange procedurewasfollowedtoincorporateTiO2 into ageopolymer(IEG),anddifferent2-Butanone concentrations wereusedinabatchreactorunderdryandhumidconditions.Variationon 2-Butanone concentrationwasfollowedbygaschromatography.ALangmuir Hinshelwood modelwas used todeterminethedisappearancerateofreactantattheinitialstageofthereaction.Gasca-Tirado, J.; Manzano-Ramirez, A.; Vazquez-Landaverde, PA.; Herrera-Diaz, EI.; Rodriguez-Ugarte, ME.; Rubio-Avalos, JC.; AmigĂł BorrĂĄs, V.... (2014). Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound. Materials Letters. 134:222-224. doi:10.1016/j.matlet.2014.07.090S22222413
The large trans-Neptunian object 2002 TC302 from combined stellar occultation, photometry, and astrometry data
Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302. Methods. Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ~ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses. Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 ± 0.005, which would be somewhat smaller if 2002 TC302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.Funding from Spanish projects AYA2014-56637-C2-1-P, AYA2017-89637-R, from FEDER, and Proyecto de Excelencia de la Junta de AndalucĂa 2012-FQM1776 is acknowledged. We would like to acknowledge financial support by the Spanish grant AYA-RTI2018-098657-JI00 âLEO-SBNAFâ (MCIU/AEI/FEDER, UE) and the financial support from the State Agency for Research of the Spanish MCIU through the âCenter of Excellence Severo Ochoaâ award for the Instituto de AstrofĂsica de AndalucĂa (SEV- 2017-0709). Part of the research received funding from the European Unionâs Horizon 2020 Research and Innovation Programme, under grant agreement no. 687378 and from the ERC programme under Grant Agreement no. 669416 Lucky Star. The following authors acknowledge the respective CNPq grants: FB-R 309578/2017-5; RV-M 304544/2017-5, 401903/2016-8; J.I.B.C. 308150/2016-3; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. This study was financed in part by the Coordenação de Aperfeiaçoamento de Pessoal de NĂvel Superior - Brasil (CAPES) - Finance Code 001 and the National Institute of Science and Technology of the e-Universe project (INCT do e-Universo, CNPq grant 465376/2014-2). GBR acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. E.F.-V. acknowledges support from the 2017 Preeminent Postdoctoral Program (P3) at UCF. C.K., R.S., A.F-T., and G.M. have been supported by the K-125015 and GINOP-2.3.2-15-2016-00003 grants of the Hungarian National Research, Development and Innovation Office (NKFIH), Hungary. G.M. was also supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grant PD-128 360. R.K. and T.P. were supported by the VEGA 2/0031/18 grant
Proteção do cafeeiro contra cercosporiose por acibenzolar-S-metil e proteĂna harpina
O objetivo deste trabalho foi avaliar, em cafeeiro suscetĂvel, a proteção contra a cercosporiose, pela aplicação da proteĂna harpina e acibenzolar-S-metil (ASM), e avaliar seu efeito na germinação de conĂdios e crescimento micelial in vitro. No primeiro experimento, cafeeiros tratados com ASM (25, 50, 100, 200 μg mL-1) receberam o inĂłculo de uma suspensĂŁo de conĂdios de Cercospora coffeicola, e a severidade da doença foi avaliada aos 30 e 60 dias apĂłs a inoculação. No segundo experimento, cafeeiros foram aspergidos com harpina (7,5, 15, 30, 60, 120 μg mL-1), tendo-se utilizado o mesmo procedimento. No terceiro experimento, plantas aspergidas previamente com ASM (200 μg mL-1) ou harpina (15 μg mL-1) foram tratadas novamente com esses produtos, aos 30 dias apĂłs terem recebido inĂłculo do patĂłgeno. ASM e harpina protegeram os cafeeiros contra cercosporiose 30 dias apĂłs a inoculação com C. coffeicola. Entretanto, 60 dias apĂłs a inoculação, apenas o ASM (200 μg mL-1), com uma ou duas aplicaçÔes, protegeu as plantas contra C. coffeicola. Os cafeeiros foram protegidos contra cercosporiose, em reaplicação de harpina, 30 dias apĂłs o primeiro tratamento com essa proteĂna. Harpina e acibenzolar-S-metil nĂŁo inibiram o desenvolvimento micelial nem a germinação in vitro dos conĂdios do patĂłgeno
- âŠ