A massive, quiescent galaxy at redshift of z=3.717

In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These have revealed the presence of massive, quiescent early-type galaxies appearing in the universe as early as z$\sim$2, an epoch 3 Gyr after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy formation models where they form rapidly at z$\sim$3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have now reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, however the evidence for their existence, and redshift, has relied entirely on coarsely sampled photometry. These early massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here, we report the spectroscopic confirmation of one of these galaxies at redshift z=3.717 with a stellar mass of 1.7$\times$10$^{11}$ M$_\odot$ whose absorption line spectrum shows no current star-formation and which has a derived age of nearly half the age of the Universe at this redshift. The observations demonstrates that the galaxy must have quickly formed the majority of its stars within the first billion years of cosmic history in an extreme and short starburst. This ancestral event is similar to those starting to be found by sub-mm wavelength surveys pointing to a possible connection between these two populations. Early formation of such massive systems is likely to require significant revisions to our picture of early galaxy assembly.Comment: 6 pages, 7 figures. This is the final preprint corresponding closely to the published version. Uploaded 6 months after publication in accordance with Nature polic

Key stakeholder perceptions about consent to participate in acute illness research: a rapid, systematic review to inform epi/pandemic research preparedness

Background A rigorous research response is required to inform clinical and public health decision-making during an epi/pandemic. However, the ethical conduct of such research, which often involves critically ill patients, may be complicated by the diminished capacity to consent and an imperative to initiate trial therapies within short time frames. Alternative approaches to taking prospective informed consent may therefore be used. We aimed to rapidly review evidence on key stakeholder (patients, their proxy decision-makers, clinicians and regulators) views concerning the acceptability of various approaches for obtaining consent relevant to pandemic-related acute illness research. Methods We conducted a rapid evidence review, using the Internet, database and hand-searching for English language empirical publications from 1996 to 2014 on stakeholder opinions of consent models (prospective informed, third-party, deferred, or waived) used in acute illness research. We excluded research on consent to treatment, screening, or other such procedures, non-emergency research and secondary studies. Papers were categorised, and data summarised using narrative synthesis. Results We screened 689 citations, reviewed 104 full-text articles and included 52. Just one paper related specifically to pandemic research. In other emergency research contexts potential research participants, clinicians and research staff found third-party, deferred, and waived consent to be acceptable as a means to feasibly conduct such research. Acceptability to potential participants was motivated by altruism, trust in the medical community, and perceived value in medical research and decreased as the perceived risks associated with participation increased. Discrepancies were observed in the acceptability of the concept and application or experience of alternative consent models. Patients accepted clinicians acting as proxy-decision makers, with preference for two decision makers as invasiveness of interventions increased. Research regulators were more cautious when approving studies conducted with alternative consent models; however, their views were generally under-represented. Conclusions Third-party, deferred, and waived consent models are broadly acceptable to potential participants, clinicians and/or researchers for emergency research. Further consultation with key stakeholders, particularly with regulators, and studies focused specifically on epi/pandemic research, are required. We highlight gaps and recommendations to inform set-up and protocol development for pandemic research and institutional review board processes

Quantification et caractérisation de la matière organique de sols alluviaux au cours de l'évolution de la végétation

Les auteurs identifient les formes et déterminent les quantités de matière organique de l'humus de 2 séries de sols alluviaux — Fluviosols (les sols dont le nom commence par une majuscule sont désignés selon le Référentiel pédologique. Principaux sols d'Europe (AFES, 1992) —, l'une sur alluvions à dominante calcaire et l'autre sur alluvions à dominante d'orthogneiss, dans le but d'établir si les caractères physico-chimiques de cette matière organique correspondent au degré d'évolution traduit par la morphologie du sol, d'une part, et par la végétation actuelle, d'autre part. Ils réalisent un premier fractionnement par tamisage à l'eau, destiné à séparer et à quantifier la matière végétale figurée et la matière végétale la plus humifiée. Sur cette dernière, ils procèdent à des extractions chimiques sélectives. Les résultats démontrent que la quantité (stock en carbone et en azote) de matière organique est un meilleur indicateur que la qualité, qui ne varie pratiquement pas en milieu calcaire et que très lentement en milieu acide. La vitesse d'évolution de l'humus de ces sols par rapport à celle de la végétation présente en moins d'un siècle une inertie marquée qui laisse entrevoir un décalage dans l'adéquation sol-végétation.Organic matter quantification and characterization of alluvial soils during vegetation evolution. In order to determine if the physical and chemical criterias of organic matter are in phase with the evolutive state expressed both by the soil morphology and by the present vegetation, forms of organic matter are identified and then quantified in the humus of 2 different series of alluvial soils (Fluviosols). One series is situated on mainly calcareous alluvia and the other on alluvia principally constituted of orthogneiss (figs 1 and 2; table I). A first fractionation, using the method of water sieving, is undertaken to separate and to estimate the particulate plant material from the best humified plant material. The latter is then selectively chemically extracted (fig 3; table III). Results show that the amount (stock in carbon and nitrogen) of organic matter is a better indicator (table II) than its quality, which virtually does not change in a calcareous environment and only slowly in acid conditions (tables IV and V). As compared with the vegetation dynamic, the slow humus evolution in these soils seems to reveal in less than 100 years a shift in the soil-vegetation relationship

European Humus Forms Reference Base 2012

Nel gennaio 2011 \ue8 stato reso disponibile un riferimento europeo per la classificazione e lo studio delle forme di humus (http://hal-agroparistech.archives-ouvertes.fr/docs/00/56/17/95/PDF/Humus_Forms_ERB _31_01_2011.pdf). Da parte degli autori della pubblicazione \ue8 attualmente in preparazione un aggiornamento della chiave che terr\ue0 conto di consigli, suggerimenti e critiche. Le basi del futuro riferimento saranno presentate in poster allo scopo di allargare la discussione verso tutti i possibili utilizzatori della classificazione, rendendoli partecipi al progetto. Nel nuovo sistema sono riprese le gi\ue0 pubblicate 10 forme di base, corrispondenti ad altrettante modalit\ue0 di biodegradazione della sostanza organica nel suolo; le cinque forme terrestri (Tangel, Amphi, Mull, Moder e Mor) e le cinque forme semiterrestri (Anmoor, Mull, Amphi, Moder e Mor) sono poste al centro di un modello che considera anche l\u2019insieme delle forme giovani (Enti), idromorfe (Hydro), superficiali (Epi) o specializzate (Rhizo e Ligno). Per la definizione delle forme di humus sono stati adottati caratteri morfo-funzionali che permettano da un lato di riconoscere le forme in campo a occhio nudo e dall\u2019altro di ottenere informazioni semplici e pratiche sui loro ambienti di formazione e tipi di funzionamento - - - - - [ABSTRACT: From 2003 on, a panel of experts in humus and humus dynamics (Humus group) has been working about a standardisation and improvement of existing national humus classifications. Some important goals have been reached, in order to share data and experiences: a) the definition of specific terms; b) a description of 15 types of diagnostic horizons and c) of 10 basic humus forms references; d) the subdivision of each main reference in 2-4 sub-unities; e) the elaboration of a general European Humus Form Reference Base (http://hal-agroparistech.archives-ouvertes.fr/docs/00/56/17/95/PDF/Humus_Forms_ERB_31_01_2011.pdf ); f) the publication of the scientific significance of this base of classification as an article [A European morpho-functional classification of humus forms. Geoderma, 164 (3-4), 138-145]. The classification will be updated every 2 years and presently the Humus group is assessing biological (general: soil, vegetation, biome; specific: fungi, bacteria, pedofauna), physical (air temperature, rainfall) and chemical (pH, mineral elements, organic matter, quality and quantity of humic components\u2026) factors which characterize basic humus forms and their varieties. The content of the new version of the classification is planned to be more \u201cpractical\u201d, like an ecological manual which lists associated humus forms and environmental data in the aim to contribute to a more precise environmental diagnosis of every analysed terrestrial and semiterrestrial European ecosystem. The principles of the classification, the diagnostic horizons and humus forms main references are presented at the General Assembly of the European Geosciences Union with the aim to stimulate the members curiosity. Interested people are invited to test the classification system in various environments and collaborate with the Humus group. Critical observations and field data/impressions are welcome as every other suggestions which can help in elaborating the 2013 version of the European humus forms classification

An extremely young massive clump forming by gravitational collapse in a primordial galaxy

When the cosmic star formation history peaks (z ~ 2), galaxies vigorously fed by cosmic reservoirs are gas dominated and contain massive star-forming clumps, thought to form by violent gravitational instabilities in highly turbulent gas-rich disks. However, a clump formation event has not been witnessed yet, and it is debated whether clumps survive energetic feedback from young stars, thus migrating inwards to form galaxy bulges. Here we report spatially resolved spectroscopy of a bright off-nuclear emission line region in a galaxy at z = 1.987. Although this region dominates the star formation in the galaxy disk, its stellar continuum remains undetected in deep imaging, revealing an extremely young (age < 10 Myr) massive clump, forming through the gravitational collapse of > 10$^9$ M$_{\odot}$ of gas. Gas consumption in this young clump is > 10 times 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 coupled with our initial estimate of their formation rate (~ 2.5 Gyr$^{-1}$) supports long lifetimes (~ 500 Myr), favouring scenarios where clumps survive feedback and grow the bulges of present-day galaxies.Comment: Published in May 7 issue of Nature (http://dx.doi.org/10.1038/nature14409