Periodic spatial variation of the electron-phonon interaction in epitaxial graphene on Ru(0001

We have performed low temperature scanning tunnelling spectroscopy (STS) measurements on graphene epitaxially grown on Ru(0001). An inelastic feature, related to the excitation of a vibrational breathing mode of the graphene lattice, was found at 360 meV. The change in the differential electrical conductance produced by this inelastic feature, which is associated with the electron-phonon interaction strength, varies spatially from one position to other of the graphene supercell. This inhomogeneity in the electronic properties of graphene on Ru(0001) results from local variations of the carbon-ruthenium interaction due to the lattice mismatch between the graphene and the Ru(0001) lattices.Comment: 6 Pages, 3 figure

Local Governance in Mexico. The Case of Nuevo Leon 2015-2021

The purpose of this paper is to provide some theoretical and empirical elements to measure the level of governance using an empirical case that will focus on the analysis of the 2015-2021 administration of the Government of the State of Nuevo Le n The governance model is evaluated based on the weighting of the degree of effectiveness efficiency and legitimacy that can be observed from the analysis of state public management and the evaluation of some public policies For the development of the project the World Bank s governance index is used as a reference which includes the measurement of six variable

A survey for water maser emission towards planetary nebulae. New detection in IRAS 17347-3139

We report on a water maser survey towards a sample of 27 planetary nebulae (PNe) using the Robledo de Chavela and Medicina single-dish antennas, as well as the Very Large Array (VLA). Two detections have been obtained: the already known water maser emission in K 3-35, and a new cluster of masers in IRAS 17347-3139. This low rate of detections is compatible with the short life-time of water molecules in PNe (~100 yr). The water maser cluster at IRAS 17347-3139 are distributed on a ellipse of size ~ 0.2" x 0.1", spatially associated with compact 1.3 cm continuum emission (simultaneously observed with the VLA). From archive VLA continuum data at 4.9, 8.4, and 14.9 GHz, a spectral index alpha = 0.76 +- 0.03 is derived for this radio source, which is consistent with either a partially optically thick ionized region or with an ionized wind. However, the latter scenario can be ruled out on mass-loss considerations, thus indicating that this source is probably a young PN. The spatial distribution and the radial velocities of the water masers are suggestive of a rotating and expanding maser ring, tracing the innermost regions of a torus formed at the end of the AGB phase. Given that the 1.3 cm continuum emission peak is located near one of the tips of the major axis of the ellipse of masers, we speculate on a possible binary nature of IRAS 17347-3139, where the radio continuum emission could belong to one of the components and the water masers would be associated with a companion.Comment: Accepted by The Astrophysical Journal. 25 pages, 6 figure

A search for water maser emission toward obscured post-AGB star and planetary nebula candidates

Water maser emission at 22 GHz is a useful probe to study the transition between the nearly spherical mass-loss in the AGB to a collimated one in the post-AGB phase. In their turn, collimated jets in the post-AGB phase could determine the shape of planetary nebulae (PNe) once photoionization starts. We intend to find new cases of post-AGB stars and PNe with water maser emission, including water fountains or water-maser-emitting PNe. We observed water maser emission in a sample of 133 objects, with a significant fraction being post-AGB and young PN candidate sources with strong obscuration. We detected this emission in 15 of them, of which seven are reported here for the first time. We identified three water fountain candidates: IRAS 17291-2147, with a total velocity spread of ~96 km/s in its water maser components and two sources (IRAS 17021-3109 and IRAS 17348-2906) that show water maser emission outside the velocity range covered by OH masers. We have also identified IRAS 17393-2727 as a possible new water-maser-emitting PN. The detection rate is higher in obscured objects (14%) than in those with optical counterparts (7%), consistent with previous results. Water maser emission seems to be common in objects that are bipolar in the near-IR (43% detection rate). The water maser spectra of water fountain candidates like IRAS 17291-2147 show significantly less maser components than others (e.g., IRAS 18113-2503). We speculate that most post-AGBs may show water maser emission with wide enough velocity spread (> 100 km/s) when observed with enough sensitivity and/or for long enough periods of time. Therefore, it may be necessary to single out a special group of "water fountains", probably defined by their high maser luminosities. We also suggest that the presence of both water and OH masers in a PN is a better tracer of its youth, rather than the presence of just one of these species.Comment: To be published in Astronomy & Astrophysics. 16 pages, 1 figure (spanning 5 pages). This version includes some minor language corrections and fixes some errors in Table

Tolerância de Noctuideos a proteína CRY1AC expressa no algodão Bollgard.

A introdução da soja Bt no cenário agrícola nacional é acompanhada pela preocupação da seleção de populações resistentes de lepidópteros suscetíveis e tolerantes às toxinas de Bacillus thuringiensis (Bt). A pressão de seleção poder ser exercida pela soja-Bt, assim como por o algodão-Bt, que expressam a mesma toxina, Cry1Ac. Portanto a avaliação da suscetibilidade/tolerância das diferentes espécies de noctuideos é de fundamental importância para definir estratégias para monitorar e prevenir os possíveis casos de resistência a Cry1Ac. Folhas de algodão (Delta Opal e da cultivar convencional NuOpal) provenientes de plantas com 30 dias de germinadas foram desidratadas, moídas e incorporadas na proporção de 2g de peso seco em 40 ml de dieta de Greene. A dieta com e sem tecidos de algodão foi oferecida como alimento para lagartas de Pseudoplusia includens, Spodoptera cosmioides e S. eridania e uma população de Anticarsia gemmatalis resistente e duas populações suscetíveis (uma população de laboratório e outra de Cruz Alta, RS) ao inseticida biológico a base de Bt, Dipel. A sobrevivência de lagartas de A. gemmatalis suscetíveis e resistentes (taxa de resistência = 103x) ao Dipel foi afetada pela presença de algodão convencional na dieta. Mas também foi significativamente afetada pela presença da toxina Cry1Ac. A sobrevivência de P. includens foi menos afetada que A. gemmatalis pela presença da toxina na dieta e também foi afetada pela presença das folhas de algodão convencional. A sobrevivência das espécies de Spodoptera não foi afetada pela presença da toxina na dieta. O ganho de peso das espécies de Spodoptera foi menos afetado pela presença da toxina, sendo esse efeito negativo mais pronunciado em A. gemmatalis, tanto nas populações suscetíveis como na resistente. As populações de A. gemmatalis provenientes de Cruz Alta encontravam-se na 3ª geração, provavelmente, menos adaptadas às condições de criação em laboratório resultando em menor sobrevivência. S. eridania, S. cosmioides e P. includens, foram as espécies mais tolerantes a toxina expressa em folhas de algodão. Lagartas de A. gemmatalis resistentes a uma formulação comercial de B. thuringiensis foram suscetíveis a toxina Cry1Ac.SICONBIOL 2011