Explore the vast range of titles available.

An extremely young star-forming region caught at gravitational collapse in a distant galaxy is shedding new light on the processes driving galaxy growth in the early Universe. Clump formation in a young galaxy Young galaxies vigorously fed by cosmic reservoirs are gas dominated and contain massive star-forming clumps. No clump formation events have yet been observed, however, and it is debated whether clumps can survive feedback from young stars and then migrate inwards to form galaxy bulges. But now Anita Zanella et al . report spatially resolved spectroscopy of an extremely young star-forming region caught at the point of gravitational collapse in a distant (redshift z = 1.987) galaxy. Gas consumption in this young clump (less than ten million years old) is more than ten times faster than in the host galaxy. The frequency of older clumps with similar masses, coupled with initial estimate of their formation rate supports long lifetimes (of about 500 million years), favouring a model where clumps do survive feedback and grow the bulges of present-day galaxies. When cosmic star formation history reaches a peak (at about redshift z ≈ 2), galaxies vigorously fed by cosmic reservoirs 1 , 2 are dominated by gas 3 , 4 and contain massive star-forming clumps 5 , 6 , which are thought to form by violent gravitational instabilities in highly turbulent gas-rich disks 7 , 8 . However, a clump formation event has not yet been observed, and it is debated whether clumps can survive energetic feedback from young stars, and afterwards migrate inwards to form galaxy bulges 9 , 10 , 11 , 12 . Here we report the spatially resolved spectroscopy of a bright off-nuclear emission line region in a galaxy at z = 1.987. Although this region dominates star formation in the galaxy disk, its stellar continuum remains undetected in deep imaging, revealing an extremely young (less than ten million years old) massive clump, forming through the gravitational collapse of more than one billion solar masses of gas. Gas consumption in this young clump is more than tenfold faster than in the host galaxy, displaying high star-formation efficiency during this phase, in agreement with our hydrodynamic simulations. The frequency of older clumps with similar masses 13 , coupled with our initial estimate of their formation rate (about 2.5 per billion years), supports long lifetimes (about 500 million years), favouring models in which clumps survive feedback and grow the bulges of present-day galaxies.

The impact of fish and oysters on components of the pelagic microbial food web (MFW) was studied in a 10 d mesocosm experiment using Mediterranean coastal waters. Two mesocosms contained natural water only (‘Controls’), 2 contained natural water with Crassostrea gigas (‘Oyster’), and 2 contained natural water with Atherina spp. (‘Fish’). Abundances and biomasses of microorganisms (viruses, bacteria, phytoplankton, heterotrophic flagellates, and ciliates) were measured to estimate their contribution to the total microbial carbon biomass. Two MFW indices, the microbial autotroph:heterotroph C biomass ratio (A:H) structural index and the gross primary production:respiration ratio (GPP:R) functional index, were defined. In the Fish mesocosms, selective predation on zooplankton led to a trophic cascade with 51% higher phytoplankton C biomass and consequently higher A:H and GPP:R than in the Controls. By the end of the experiment, the Oyster mesocosms had a bacterial C biomass 87% higher and phytoplankton C biomass 93% lower than the Controls, giving significantly lower A:H and GPP:R (<1). Overall, the results showed that wild zooplanktivorous fish had a cascading trophic effect, making the MFW more autotrophic (both indices >1), whereas oyster activities made the MFW more heterotrophic (both indices <1). These MFW indices can therefore be used to assess the impact of multiple local and global forcing factors on the MFW. The results presented here also have implications for sustainable management of coastal environments, suggesting that intense cultivation of filter feeders can be coupled with management to encourage wild local zooplanktivorous fishes to maintain a more resilient system and preserve the equilibrium of the MFW.

We present a new strategy to optimise the electromagnetic follow-up of gravitational wave triggers. This method is based on the widely used galaxy targeting approach where we add the stellar mass of galaxies in order to prioritise the more massive galaxies. We crossmatched the GLADE galaxy catalog with the AllWISE catalog up to 400Mpc with an efficiency of \\(\\sim\\)93\\%, and derived stellar masses using a stellar-to-mass ratio using the WISE1 band luminosity. We developed a new grade to rank galaxies combining their 3D localisation probability associated to the gravitational wave event with the new stellar mass information. The efficiency of this new approach is illustrated with the GW170817 event, which shows that its host galaxy, NGC4993, is ranked at the first place using this new method. The catalog, named Mangrove, is publicly available and the ranking of galaxies is automatically provided through a dedicated web site for each gravitational wave event.

Star formation rate functions (SFRFs) give an instantaneous view of the distribution of star formation rates (SFRs) in galaxies at different epochs. They are a complementary and more stringent test for models than the galaxy stellar mass function, which gives an integrated view of the past star formation activity. However, the exploration of SFRFs has been limited thus far due to difficulties in assessing the SFR from observed quantities and probing the SFRF over a wide range of SFRs. We overcome these limitations thanks to an original method that predicts the infrared luminosity from the rest-frame UV/optical color of a galaxy and then its SFR over a wide range of stellar masses and redshifts. We applied this technique to the deep imaging survey HSC-CLAUDS combined with near-infrared and UV photometry. We provide the first SFR functions with reliable measurements in the high- and low-SFR regimes up to \\(z=2\\) and compare our results with previous observations and four state-of-the-art hydrodynamical simulations.

Millipedes and woodlice were sampled at 27 sites in a mosaic landscape in order to establish the extent to which the macroarthropod community changed with different plant formations. Multivariate analyses conducted on abundance data for ten species revealed four main types of macroarthropod communities. This classification was highly correlated with vegetation structure and particularly the degree of openness of the sites. Communities dominated by Ommatoiulus rutilans (Julidae) occurred in open grassland; those dominated by Glomeris marginata (Glomeridae) plus Porcellio gallicus (Porcellionidae) were found at the least open sites, with a high oak cover; communities with a high proportion of the endemic glomerid Glomeris annulata occurred in semi-open sites with a substantial cover of shrubs. Species diversity was significantly higher at the semi-open sites, this being interpreted as an edge effect. Population density and biomass were lower at wooded sites. In the context of a regional trend towards woodland expansion, the results are discussed from the viewpoint of conserving the pool of millipede and woodlouse species and of maintaining the abundance of saprophagous macroarthropods in the region's ecosystems.[PUBLICATION ABSTRACT]

•We set up a murine model of sublingual immunotherapy for birch pollen allergy.•We assessed the efficacy of a pharmaceutical-grade recombinant allergen Bet v 1a.•Mucoadhesive particles allowed to decrease the dose of recombinant Bet v 1a.•Mucoadhesive particles provided a rapid onset of action. Second generation sublingual allergy vaccines based upon recombinant allergens combined with vector systems are being developed as an alternative to conventional allergen extracts. Herein, we evaluated the efficacy of a recombinant form of the major allergen Bet v 1a (rBet v 1a) formulated as a mucoadhesive particle in a preclinical model of birch pollen (BP) respiratory allergy. BALB/c mice were sensitized to BP extracts by intraperitoneal injections followed by aerosol exposures. Sensitized mice underwent sublingual immunotherapy (SLIT) twice a week for eight weeks with either a BP extract or rBet v 1a formulated in amylopectin-based microparticles (MPA). SLIT efficacy was assessed using whole body plethysmography, lung histology and cell counts in broncho-alveolar lavages (BAL) as read outs. BP and/or rBet v 1a-specific T cell and antibody responses were monitored in lung and serum, respectively. IgA levels were measured in saliva. Mice sensitized to BP exhibit chronic airway hyperresponsiveness (AHR), lung inflammation (documented by compliance and resistance measurements), eosinophil infiltrates in BAL, as well as Bet v 1-specific Th2 biased responses. Both SLIT with soluble rBet v 1a (50μg/dose) and BP extract (equivalent to 50μg rBet v 1 per dose) lead to a significant reduction in AHR, lung eosinophilia and Th2 responses. A sub-optimal dose of 5μg of rBet v 1a displays a similar level of efficacy with a significant decrease of Th2 responses when formulated with MPA microparticles. In addition, allergen vectorization with mucoadhesive particles allows a faster reduction in AHR in sensitized animals. We demonstrate in a murine model of chronic BP respiratory allergy the efficacy of SLIT with vectorized rBet v 1a. Thus, combining recombinant allergens with mucoadhesive vector systems paves the ground for improved second generation sublingual allergy vaccines.

Gamma-ray Bursts (GRBs) are the most powerful transients in the Universe, over-shining for a few seconds all other \\(\\gamma\\)-ray sky sources. Their emission is produced within narrowly collimated relativistic jets launched after the core-collapse of massive stars or the merger of compact binaries. THESEUS will open a new window for the use of GRBs as cosmological tools by securing a statistically significant sample of high-\\(z\\) GRBs, as well as by providing a large number of GRBs at low-intermediate redshifts extending the current samples to low luminosities. The wide energy band and unprecedented sensitivity of the Soft X-ray Imager (SXI) and X-Gamma rays Imaging Spectrometer (XGIS) instruments provide us a new route to unveil the nature of the prompt emission. For the first time, a full characterisation of the prompt emission spectrum from 0.3 keV to 10 MeV with unprecedented large count statistics will be possible revealing the signatures of synchrotron emission. SXI spectra, extending down to 0.3 keV, will constrain the local metal absorption and, for the brightest events, the progenitors' ejecta composition. Investigation of the nature of the internal energy dissipation mechanisms will be obtained through the systematic study with XGIS of the sub-second variability unexplored so far over such a wide energy range. THESEUS will follow the spectral evolution of the prompt emission down to the soft X-ray band during the early steep decay and through the plateau phase with the unique ability of extending above 10 keV the spectral study of these early afterglow emission phases.

The phase noise and frequency stability measurements of 1 GHz, 100 MHz and 10 MHz signals are presented which have been synthesised from the 11.2 GHz outputs of two nominally identical independent cryogenic microwave sapphire oscillators.