Evaluación de comunidades microbianas edáficas mediante CLPP : estandarización de una técnica de laboratorio para reemplazar microplacas comerciales

129-136Variation of soil-microbial communities are good bioindicators of human impacts in soils, such as different soils management or contamination. Considering that traditional methods of isolation and taxonomic analysis do not consider the functionality of the microbial community, Community-Level Physiological Profiles (CLPP) emerged as a complementary methodology to study microbial communities. Several studies have shown that Biolog® EcoPlates® are very useful for determining physiological differences between communities from different samples. However, commercial microplates have some disadvantages which led us to the idea of replacing them by microplates prepared in the laboratory (Laboratory's). Here, we compared both types of microplates using soil samples from a bioremediation assay. We compared a) the average well color development for each sample, b) the averages of absorbance values for each type of microplate, c) Principal Components, and d) Shannon-Weaver's diversity index (H). Although Laboratory's showed significantly lower Average absorbance values than EcoPlates®, the principal component analysis and diversity index did not differ between types of microplates. In conclusion, both types of microplates showed a relatively similar ability to detect differences in the CLPP of the treatments studied. Consequently, microplates prepared in laboratory are a reliable and economical tool to study the physiology of soil microbial communities

Evaluación de comunidades microbianas edáficas mediante CLPP : estandarización de una técnica de laboratorio para reemplazar microplacas comerciales

129-136Variation of soil-microbial communities are good bioindicators of human impacts in soils, such as different soils management or contamination. Considering that traditional methods of isolation and taxonomic analysis do not consider the functionality of the microbial community, Community-Level Physiological Profiles (CLPP) emerged as a complementary methodology to study microbial communities. Several studies have shown that Biolog® EcoPlates® are very useful for determining physiological differences between communities from different samples. However, commercial microplates have some disadvantages which led us to the idea of replacing them by microplates prepared in the laboratory (Laboratory's). Here, we compared both types of microplates using soil samples from a bioremediation assay. We compared a) the average well color development for each sample, b) the averages of absorbance values for each type of microplate, c) Principal Components, and d) Shannon-Weaver's diversity index (H). Although Laboratory's showed significantly lower Average absorbance values than EcoPlates®, the principal component analysis and diversity index did not differ between types of microplates. In conclusion, both types of microplates showed a relatively similar ability to detect differences in the CLPP of the treatments studied. Consequently, microplates prepared in laboratory are a reliable and economical tool to study the physiology of soil microbial communities

Estimating preferences for controlling beach erosion in Sicily

This study applied discrete-choice experiments to estimate preferences for a program aimed at reducing the retreatment of the sandy beach at "Lido di Noto", a renowned Sicilian bathing resort close to Noto (Italy). Econometric analysis of data was based on Multinomial Logit (MNL), Latent Class (LC) and Mixed Logit (MXL) models. Findings shown that users appreciated the advancement of the current coastline through nourishment, and negatively perceived the construction of emerged sea barriers. MXL and LC models revealed that preferences were heterogeneous

SAX J1808.4-3658, an accreting millisecond pulsar shining in gamma rays?

We report the detection of a possible gamma-ray counterpart of the accreting millisecond pulsar SAX J1808.4-3658. The analysis of ~6 years of data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (Fermi-LAT) within a region of 15deg radius around the position of the pulsar reveals a point gamma-ray source detected at a significance of ~6 sigma (Test Statistic TS = 32), with position compatible with that of SAX J1808.4-3658 within 95% Confidence Level. The energy flux in the energy range between 0.6 GeV and 10 GeV amounts to (2.1 +- 0.5) x 10-12 erg cm-2 s-1 and the spectrum is well-represented by a power-law function with photon index 2.1 +- 0.1. We searched for significant variation of the flux at the spin frequency of the pulsar and for orbital modulation, taking into account the trials due to the uncertainties in the position, the orbital motion of the pulsar and the intrinsic evolution of the pulsar spin. No significant deviation from a constant flux at any time scale was found, preventing a firm identification via time variability. Nonetheless, the association of the LAT source as the gamma-ray counterpart of SAX J1808.4-3658 would match the emission expected from the millisecond pulsar, if it switches on as a rotation-powered source during X-ray quiescence.Comment: 8 pages, 4 figures, accepted by MNRA

An XMM-Newton and INTEGRAL view on the hard state of EXO 1745-248 during its 2015 outburst

CONTEXT - Transient low-mass X-ray binaries (LMXBs) often show outbursts lasting typically a few-weeks and characterized by a high X-ray luminosity ($L_{x} \approx 10^{36}-10^{38}$ erg/sec), while for most of the time they are found in X-ray quiescence ($L_X\approx10^{31} -10^{33}$ erg/sec). EXO 1745-248 is one of them. AIMS - The broad-band coverage, and the sensitivity of instrument on board of {\xmm} and {\igr}, offers the opportunity to characterize the hard X-ray spectrum during {\exo} outburst. METHODS - In this paper we report on quasi-simultaneous {\xmm} and {\igr} observations of the X-ray transient {\exo} located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16th) shown by the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of $\simeq10^{37}$~{\lumcgs}. RESULTS - The spectral continuum was dominated by thermal Comptonization of seed photons with temperature $kT_{in}\simeq1.3$ keV, by a cloud with moderate optical depth $\tau\simeq2$ and electron temperature $kT_e\simeq 40$ keV. A weaker soft thermal component at temperature $kT_{th}\simeq0.6$--0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on-board {\xmm}; features at energies compatible with K-$\alpha$ transitions of ionized sulfur, argon, calcium and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at $20\pm6$ gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. (Abridged)Comment: 14 pages, 6 figure, 2 tables. Accepted for publication on A&A (21/03/2017

Effects of atomic diffraction on the Collective Atomic Recoil Laser

We formulate a wave atom optics theory of the Collective Atomic Recoil Laser, where the atomic center-of-mass motion is treated quantum mechanically. By comparing the predictions of this theory with those of the ray atom optics theory, which treats the center-of-mass motion classically, we show that for the case of a far off-resonant pump laser the ray optics model fails to predict the linear response of the CARL when the temperature is of the order of the recoil temperature or less. This is due to the fact that in theis temperature regime one can no longer ignore the effects of matter-wave diffraction on the atomic center-of-mass motion.Comment: plain tex, 10 pages, 10 figure

El ácaro de aves tropicales Ornithonyssus bursa (Acari: Mesostigmata: Macronyssidae) parasitando al estornino pinto Sturnus vulgaris (Aves: Passeriformes: Sturnidae), un ave invasiva en el centro de Argentina: una aproximación a la fauna bacteriana de este ácaro

The tropical fowl mite (Ornithonyssus bursa) is a common parasite of domestic and wild birds in tropical and subtropical regions. This mite can cause irritation, severe dermatitis and anemia. The European starling (Sturnus vulgaris) is an invasive bird in Argentina. Both O. bursa and S. vulgaris have high reproductive rates with implications for public health. The goals of our study were to report the occurrence of this mite parasitizing the starlings, and test for the presence of bacteria that could be potentially associated with the mites. The study was conducted in Estación de Cría de Animales Silvestres (Buenos Aires, Argentina). Mites were collected from starlings and stored in 96% ethanol, and prepare for their identification under an optic microscope. Molecular studies were conducted in order to examine the presence of bacteria. All mites were identified as O. bursa. We detected for the first time Wolbachia sp., associated with the genus Ornithonyssus. In contrast, mites were negative for species of Rickettsia, Bartonella and Borrelia. In addition to the damage that the starlings produce as an invasive species in central Argentina, herein we report the association of these birds with O. bursa, favoring the dispersal of the mites and their colonization to other birds.Ornithonyssus bursa es un parásito común en aves domésticas y silvestres de regiones tropicales y subtropicales que puede causar irritación, dermatitis severa y anemia. El estornino pinto (Sturnus vulgaris) es un ave invasora en Argentina. Tanto O. bursa como S. vulgaris tienen altas tasas de reproducción con implicaciones en salud pública. Los objetivos del estudio fueron reportar la presencia de este ácaro parasitando a los estorninos y comprobar la potencial asociación de bacterias a los ácaros. El estudio se realizó en la Estación de Cría de Animales Silvestres (Buenos Aires, Argentina). Los ácaros se obtuvieron de estorninos, se almacenaron en etanol 96% y se prepararon para su identificación al microscopio óptico. Se realizaron estudios moleculares con el fin de examinar la presencia de bacterias. Todos los ácaros se identificaron como O. bursa. Se detectó por primera vez la presencia de Wolbachia sp. asociada con el género Ornithonyssus. En contraste, los resultados fueron negativos para las especies de Rickettsia, Bartonella y Borrelia. Además del dano˜ que producen los estorninos como una especie invasora en el centro de Argentina, se presenta la asociación de estas aves con O. bursa, lo que favorece la dispersión de los ácaros y su colonización hacia otras aves.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse