E-BOSS: An Extensive stellar BOw Shock Survey. II. Catalogue second release

Context. Stellar bow shocks have been studied not only observationally, but also theoretically since the late 1980s. Only a few catalogues of them exist. The bow shocks show emission along all the electromagnetic spectrum, but they are detected more easily in infrared wavelengths. The release of new and high-quality infrared data eases the discovery and subsequent study of new objects. Aims. We search stellar bow-shock candidates associated with nearby runaway stars, and gather them together with those found elsewhere, to enlarge the list of the E-BOSS first release. We aim to characterize the bow-shock candidates and provide a database suitable for statistical studies. We investigate the low-frequency radio emission at the position of the bow-shock features, that can contribute to further studies of high-energy emission from these objects. Methods. We considered samples from different literature sources and searched for bow-shaped structures associated with stars in the Wide-field Infrared Survey Explorer (WISE) images. We looked for each bow-shock candidate on centimeter radio surveys. Results. We reunited 45 bow-shock candidates and generated composed WISE images to show the emission in different infrared bands. Among them there are new sources, previously studied objects, and bow shocks found serendipitously. Five bow shocks show evidence of radio emission. Conclusions. Stellar bow shocks constitute an active field with open questions and enormous amounts of data to be analyzed. Future research at all wavelengths databases, and use of instruments like Gaia, will provide a more complete picture of these objects. For instance, infrared spectral energy distributions can give information about physical parameters of the bow shock matter. In addition, dedicated high-sensitivity radio observations can help to understand the radio-$\gamma$ connection.Comment: 20 pages, 11 figures, and 8 tables. Accepted for publication in A&

Egg parasitoid exploitation of plant volatiles induced by single or concurrent attack of a zoophytophagous predator and an invasive phytophagous pest

Zoophytophagous insect predators can induce physiological responses in plants by activating defence signalling pathways, but whether plants can respond to facultative phytophagy by recruiting natural enemies remains to be investigated. In Y-tube olfactometer bioassays, using a system including a Vicia faba plant, the zoophytophagous predator Podisus maculiventris and the egg parasitoid Telenomus podisi, we first demonstrated that T. podisi females are attracted by broad bean plants damaged by feeding activity of P. maculiventris and on which host egg masses had been laid, while they are not attracted by undamaged plants or plants damaged by feeding activity alone. In a second experiment, we evaluated the impact of the invasive phytophagous pest Halyomorpha halys on this plant volatile-mediated tritrophic communication. Results showed that the invasive herbivorous adults do not induce plants to recruit the native egg parasitoid, but they can disrupt the local infochemical network. In fact, T. podisi females are not attracted by volatiles emitted by plants damaged by H. halys feeding alone or combined with oviposition activity, nor are they attracted by plants concurrently infested by P. maculiventris and H. halys, indicating the specificity in the parasitoid response and the ability of the invasive herbivore in interrupting the semiochemical communication between plants and native egg parasitoids. To the best of our knowledge, this is the first study showing that zoophytophagous predator attacks induce indirect plant defences similarly to those defence strategies adopted by plants as a consequence of single or concurrent infestations of herbivorous insects

Evidence of non-thermal X-ray emission from HH 80

Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km/s, creating strong shocks when interacting with interstellar medium. Several cases of jets have been detected in X-rays, typically showing soft emission. For the first time, we report evidence of hard X-ray emission possibly related to non-thermal processes not explained by previous models of the post-shock emission predicted in the jet/ambient interaction scenario. HH 80 is located at the south head of the jet associated to the massive protostar IRAS 18162-2048. It shows soft and hard X-ray emission in regions that are spatially separated, with the soft X-ray emission region situated behind the region of hard X-ray emission. We propose a scenario for HH 80 where soft X-ray emission is associated to thermal processes from the interaction of the jet with denser ambient matter and the hard X-ray emission is produced by synchrotron radiation at the front shock.Comment: Accepted for publication in ApJ

Pheromone-mediated mating disruption of the European grain moth Nemapogon granellus in ham factories

Nemapogon granellus is a lepidopteran species that can cause significant damage to stored animal products such as meats, sausages and cheeses. In the warehouses where such products are stored, pheromone-based control ap-proaches can avoid or reduce insecticide chemical treatments and be more effective than traditional control methods. This study aimed to evaluate the effectiveness of mating disruption (MD) techniques to control N. granellus populations in ham factories. Trials were conducted in two factories located in Northern Italy. In both locations two warehouses were selected: a warehouse test where dispensers, loaded with 10 mg of N. granellus pheromone, were deployed at a density ranging from 1 unit/22.5 m3 (factory A) to 1 unit/25 m3 (factory B), and a control warehouse left untreated. To assess the mating disruption efficacy, the reduction of the number of mated females in water traps, placed in control and treated warehouses, was used as main parameter. The results indicated a substantial reduction in mated females in the treated warehouses in comparison with control warehouses in both the sites of experiments. In detail, the total number of mated females sampled in water traps was above 90% in control warehouses, in warehouses treated with MD technique this percentage was below 50%. In addition, a "trap shutdown" effect was recorded in MD treated warehouses of both factories. These findings suggest that mating disruption is a promising technique that can be positively applied in the integrated pest management of N. granellus in ham factories

Detection of nonthermal emission from the bow shock of a massive runaway star

The environs of massive, early-type stars have been inspected in recent years in the search for sites where particles can be accelerated up to relativistic energies. Wind regions of massive binaries that collide have already been established as sources of high-energy emission; however, there is a different scenario for massive stars where strong shocks can also be produced: the bow-shaped region of matter piled up by the action of the stellar strong wind of a runaway star interacting with the interstellar medium. We study the bow-shock region produced by a very massive runaway star, BD+43 3654, to look for nonthermal radio emission as evidence of a relativistic particle population. We observed the field of BD+43 3654 at two frequencies, 1.42 and 4.86 GHz, with the Very Large Array (VLA), and obtained a spectral index map of the radio emission. We have detected, for the first time, nonthermal radio emission from the bow shock of a massive runaway star. After analyzing the radiative mechanisms that can be at work, we conclude that the region under study could produce enough relativistic particles whose radiation might be detectable by forthcoming gamma-ray instruments, like CTA North.Comment: Accepted in Astronomy and Astrophysics Letter

The invasive stink bug Halyomorpha halys affects the reproductive success and the experience-mediated behavioural responses of the egg parasitoid Trissolcus basalis

Invasive species, because of their lack of co-evolutionary history with recipient communities, can act as “evolutionary traps” causing disconnects between natural enemy behavioural responses and the suitability of the invasive species as a prey/host resource. Invasion of exotic species in non-native environments may have several ecological effects, including consequences for the experience-mediated behavioural responses of indigenous foragers. Experience is usually thought to help resident species to buffer against negative impacts of new invasive species, including escaping from evolutionary traps. Here we hypothesized that the impact of foraging experience depends on whether an indigenous egg parasitoid can correctly assess the resource suitability of a new invasive species for offspring development. We showed that the invasive stink bug Halyomorpha halys acts as an evolutionary trap for the indigenous egg parasitoid Trissolcus basalis leading to unsuccessful development of ~ 95% of the eggs laid in this host species. In a mixed scenario in which the associated resident stink bug Nezara viridula co-occurs with the invasive H. halys, we showed that oviposition experience in the low quality invasive host induces in T. basalis similar responses to those of the associated host. These results suggest that foraging experience does not lead to avoidance of an evolutionary trap. We discuss parasitoid foraging experience and reproductive success in the light of the evolutionary trap framework with implication for biological control

In silico identification of small molecules as new cdc25 inhibitors through the correlation between chemosensitivity and protein expression pattern

The cell division cycle 25 (Cdc25) protein family plays a crucial role in controlling cell proliferation, making it an excellent target for cancer therapy. In this work, a set of small molecules were identified as Cdc25 modulators by applying a mixed ligand-structure-based approach and taking advantage of the correlation between the chemosensitivity of selected structures and the protein expression pattern of the proposed target. In the first step of the in silico protocol, a set of molecules acting as Cdc25 inhibitors were identified through a new ligand-based protocol and the evaluation of a large database of molecular structures. Subsequently, induced-fit docking (IFD) studies allowed us to further reduce the number of compounds biologically screened. In vitro antiproliferative and enzymatic inhibition assays on the selected compounds led to the identification of new structurally heterogeneous inhibitors of Cdc25 proteins. Among them, J3955, the most active inhibitor, showed concentration-dependent antiproliferative activity against HepG2 cells, with GI50 in the low micromolar range. When J3955 was tested in cell-cycle perturbation experiments, it caused mitotic failure by G2/M-phase cell-cycle arrest. Finally, Western blotting analysis showed an increment of phosphorylated Cdk1 levels in cells exposed to J3955, indicating its specific influence in cellular pathways involving Cdc25 proteins

High-resolution radio emission from RCW 49/Westerlund 2

Aims. The HII region RCW 49 and its ionizing cluster form an extensive, complex region that has been widely studied at infrared (IR) and optical wavelengths. The Molonglo 843 MHz and Australia Telescope Compact Array data at 1.4 and 2.4 GHz showed two shells. Recent high-resolution IR imaging revealed a complex dust structure and ongoing star formation. New high-bandwidth and high-resolution data of the RCW 49 field have been obtained to survey the radio emission at arcsec scale and investigate the small-scale features and nature of the HII region. Methods. Radio observations were collected with the new 2-GHz bandwidth receivers and the CABB correlator of the Australia Telescope Compact Array [ATCA], at 5.5 and 9.0 GHz. In addition, archival observations at 1.4 and 2.4 GHz have been re-reduced and re-analyzed in conjunction with observations in the optical, IR, X-ray, and gamma-ray regimes. Results. The new 2-GHz bandwidth data result in the most detailed radio continuum images of RCW 49 to date. The radio emission closely mimics the near-IR emission observed by Spitzer, showing pillars and filaments. The brightest continuum emission comes from the region known as the bridge. The overall flattish spectral index is typically consistent with a free-free emission mechanism. However, hints of nonthermal components are also present in the bridge. An interesting jet-like structure surrounded by a bubble feature whose nature is still unclear has been discovered close to the Westerlund 2 core. Two apparent bow shocks and a number of discrete sources have been detected as well in the surroundings of RCW 49. In addition, we also report on and discuss the possible detection of a hydrogen recombination line. Conclusions. The radio results support an association between the cm continuum and molecular emission. The detection of the radio recombination line kinematically favors a RCW 49 distance of 6–7 kpc. If the negative spectral indices measured at the bridge should be confirmed to be caused by synchrotron emission, we propose a scenario where high-energy emission could be produced. Finally, the newly discovered jet-like structure appears to be an intriguing source that deserves a detailed study by itself