Extended-spectrum beta-lactamases-producing <i>Escherichia coli</i> in common vampire bats <i>Desmodus rotundus</i> and livestock in Peru

Antibiotic resistance mediated by bacterial production of extended‐spectrum beta‐lactamase (ESBL) is a global threat to public health. ESBL resistance is most commonly hospital‐acquired; however, infections acquired outside of hospital settings have raised concerns over the role of livestock and wildlife in the zoonotic spread of ESBL‐producing bacteria. Only limited data are available on the circulation of ESBL‐producing bacteria in animals. Here, we report ESBL‐producing Escherichia coli in wild common vampire bats Desmodus rotundus and livestock near Lima, Peru. Molecular analyses revealed that most of this resistance resulted from the expression of blaCTX‐M‐15 genes carried by plasmids, which are disseminating worldwide in hospital settings and have also been observed in healthy children of Peru. Multilocus sequence typing showed a diverse pool of E. coli strains carrying this resistance that were not always host species‐specific, suggesting sharing of strains between species or infection from a common source. This study shows widespread ESBL resistance in wild and domestic animals, supporting animal communities as a potential source of resistance. Future work is needed to elucidate the role of bats in the dissemination of antibiotic‐resistant strains of public health importance and to understand the origin of the observed resistance

Physical Properties, Star Formation, and Active Galactic Nucleus Activity in Balmer Break Galaxies at 0 < z < 1

We present a spectroscopic study with the derivation of the physical properties of 37 Balmer break galaxies, which have the necessary lines to locate them in star-forming-AGN diagnostic diagrams. These galaxies span a redshift range from 0.045 to 0.93 and are somewhat less massive than similar samples of previous works. The studied sample has multiwavelength photometric data coverage from the ultraviolet to MIR Spitzer bands. We investigate the connection between star formation and AGN activity via optical, mass-excitation (MEx) and MIR diagnostic diagrams. Through optical diagrams, 31 (84%) star-forming galaxies, 2 (5%) composite galaxies and 3 (8%) AGNs were classified, whereas from the MEx diagram only one galaxy was classified as AGN. A total of 19 galaxies have photometry available in all the IRAC/Spitzer bands. Of these, 3 AGN candidates were not classified as AGN in the optical diagrams, suggesting they are dusty/obscured AGNs, or that nuclear star formation has diluted their contributions. Furthermore, the relationship between SFR surface density (\Sigma_{SFR}) and stellar mass surface density per time unit (\Sigma_{M_{\ast}/\tau}) as a function of redshift was investigated using the [OII] \lambda3727, 3729, H\alpha \lambda6563 luminosities, which revealed that both quantities are larger for higher redshift galaxies. We also studied the SFR and SSFR versus stellar mass and color relations, with the more massive galaxies having higher SFR values but lower SSFR values than less massive galaxies. These results are consistent with previous ones showing that, at a given mass, high-redshift galaxies have on average larger SFR and SSFR values than low-redshift galaxies. Finally, bluer galaxies have larger SSFR values than redder galaxies and for a given color the SSFR is larger for higher redshift galaxies.Comment: preprint version, 36 pages, 17 figures, 3 tables, accepted for publication in the Astrophysical Journa

Searching for galactic sources in the Swift GRB catalog

Since the early 1990s Gamma Ray Bursts have been accepted to be of extra-galactic origin due to the isotropic distribution observed by BATSE and the redshifts observed via absorption line spectroscopy. Nevertheless, upon further examination at least one case turned out to be of galactic origin. This particular event presented a Fast Rise, Exponential Decay (FRED) structure which leads us to believe that other FRED sources might also be Galactic. This study was set out to estimate the most probable degree of contamination by galactic sources that certain samples of FREDs have. In order to quantify the degree of anisotropy the average dipolar and quadripolar moments of each sample of GRBs with respect to the galactic plane were calculated. This was then compared to the probability distribution of simulated samples comprised of a combination of isotropically generated sources and galactic sources. We observe that the dipolar and quadripolar moments of the selected subsamples of FREDs are found more than two standard deviations outside those of random isotropically generated samples.The most probable degree of contamination by galactic sources for the FRED GRBs of the Swift catalog detected until February 2011 that do not have a known redshift is about 21 out of 77 sources which is roughly equal to 27%. Furthermore we observe, that by removing from this sample those bursts that may have any type of indirect redshift indicator and multiple peaks gives the most probable contamination increases up to 34% (17 out of 49 sources). It is probable that a high degree of contamination by galactic sources occurs among the single peak FREDs observed by Swift.Comment: Published to A&A, 4 pages, 5 figures, this arXiv version includes appended table with all the bursts considered in this stud

Treating hummingbirds as feathered bees : a case of ethological cross-pollination

Hummingbirds feed from hundreds of flowers every day. The properties of these flowers provide these birds with a wealth of information about colour, space and time to guide how they forage. To understand how hummingbirds might use this information, researchers have adapted established laboratory paradigms for use in the field. In recent years, however, experimental inspiration has come less from other birds, and more from looking at other nectar-feeders, particularly honeybees and bumblebees, which have been models for foraging behaviour and cognition for over a century. In a world in which the cognitive abilities of bees regularly make the news, research on the influence of ecology and sensory systems on bee behaviour is leading to novel insights in hummingbird cognition. As methods designed to study insects in the laboratory are being applied to hummingbirds in the field, converging methods can help us identify and understand convergence in cognition, behaviour and ecology.PostprintPeer reviewe

Principios de manejo de control quimico del tizon tardio de la papa en Ecuador.

Es necesario establecer con claridad los principios del manejo químico de la enfermedad antes que recomendaciones explícitas del uso de fungicidas. Para establecer los principios de manejo, a su vez es necesario conocer la eficacia de control y los riesgos de resistencia de los patógenos a los fungicidas. Considerando que la base del control de la enfermedad es la rotación de fungicidas, posibles sinergias y antagonismos deben ser establecidos. Además, los niveles globales de toxicidad deben ser bajos y la eficacia alta; todos estos aspectos deben ser considerados para establecer los principios de manejo del control químico. Con estos antecedentes, estudios de eficacia, resistencia del patógeno a los fungicidas, rotación de fungicidas han permitido identificar los principios de manejo del tizón tardío, lo que permitirá el manejo sustentable de la enfermedad