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1.
Sci Rep ; 14(1): 8249, 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38589701

RESUMEN

The variable solar cycle of activity is a long-standing problem in physics. It modulates the overall level of space weather activity at earth, which in turn can have significant societal impact. The Hilbert transform of the sunspot number is used to map the variable length, approximately 11 year Schwabe cycle onto a uniform clock. The clock is used to correlate extreme space weather seen in the aa index, the longest continuous geomagnetic record at earth, with the record of solar active region areas and latitudes since 1874. This shows that a clear switch-off of the most extreme space weather events occurs when > 90 % of solar active region areas have moved to within about 15° of the solar equator, from regions of high gradient in solar differential rotation which can power coronal mass ejections, to a region where solar differential rotation is almost constant with latitude. More moderate space weather events which coincide with 27 day solar rotation recurrences in the aa index, consistent with stable, persistent source regions of high speed streams, commence when the centroid of solar active region areas moves to within 15° of the solar equator. This offers a physical explanation for the longstanding identification of a two component cycle of activity in the aa index.

2.
Phys Rev Lett ; 126(12): 125101, 2021 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-33834792

RESUMEN

Multipoint in situ observations of the solar wind are used to identify the magnetic topology and current density of turbulent structures. We find that at least 35% of all structures are both actively evolving and carrying the strongest currents, actively dissipating, and heating the plasma. These structures are comprised of ∼1/5 3D plasmoids, ∼3/5 flux ropes, and ∼1/5 3D X points consistent with magnetic reconnection. Actively evolving and passively advecting structures are both close to log-normally distributed. This provides direct evidence for the significant role of strong turbulence, evolving via magnetic shearing and reconnection, in mediating dissipation and solar wind heating.

3.
Nat Commun ; 12(1): 1842, 2021 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-33758181

RESUMEN

Geomagnetic substorms are a global magnetospheric reconfiguration, during which energy is abruptly transported to the ionosphere. Central to this are the auroral electrojets, large-scale ionospheric currents that are part of a larger three-dimensional system, the substorm current wedge. Many, often conflicting, magnetospheric reconfiguration scenarios have been proposed to describe the substorm current wedge evolution and structure. SuperMAG is a worldwide collaboration providing easy access to ground based magnetometer data. Here we show application of techniques from network science to analyze data from 137 SuperMAG ground-based magnetometers. We calculate a time-varying directed network and perform community detection on the network, identifying locally dense groups of connections. Analysis of 41 substorms exhibit robust structural change from many small, uncorrelated current systems before substorm onset, to a large spatially-extended coherent system, approximately 10 minutes after onset. We interpret this as strong indication that the auroral electrojet system during substorm expansions is inherently a large-scale phenomenon and is not solely due to many meso-scale wedgelets.

4.
J Psychosom Obstet Gynaecol ; 40(1): 2-18, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-29172958

RESUMEN

OBJECTIVE: Lifestyle (smoking, drinking alcohol) and body mass index (BMI) predictors of successful outcomes in assisted reproductive technology (ART) treatments were examined in this meta-analysis. METHOD: A bibliographic search was undertaken using six databases. The review was informed by PRISMA/MOOSE guidelines. Meta-analytic data were analysed using random effects models. RESULTS: We included 77 studies examining effects of BMI, smoking and drinking alcohol. Patients with a BMI< =24.9 were significantly more likely to achieve LB/pregnancy than with BMI> =25 OR = 1.219 (95% CI:1.128-1.319, z = 4.971, p < .001; I2 = 53.779%, p = .001). Non-smokers were significantly more likely to achieve a LB or pregnancy than smokers OR = 1.457 (95% CI:1.228-1.727, z = 4.324, p < .001; I2 = 51.883; p = .001). Meta-regression revealed the number of embryos transferred significantly moderated the effects of smoking on ART outcomes, and there was a trend indicating primary infertility and high BMI were also significant moderators. The evidence for drinking alcohol was inconclusive due to the small number of studies. CONCLUSIONS: This meta-analysis confirms that ART treatment success can be predicted with lifestyle factors. Further, non-smokers' relative odds of pregnancy/live birth increase as more embryos were transferred but there was a trend that the odds of pregnancy/live birth decrease with primary infertility and high BMI.


Asunto(s)
Índice de Masa Corporal , Estilo de Vida , Técnicas Reproductivas Asistidas/estadística & datos numéricos , Consumo de Bebidas Alcohólicas/efectos adversos , Femenino , Humanos , Embarazo , Resultado del Embarazo , Índice de Embarazo , Fumar/efectos adversos , Resultado del Tratamiento
5.
Science ; 361(6406): 1016-1019, 2018 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-30190403

RESUMEN

Galaxies grow inefficiently, with only a small percentage of the available gas converted into stars each free-fall time. Feedback processes, such as outflowing winds driven by radiation pressure, supernovae, or supermassive black hole accretion, can act to halt star formation if they heat or expel the gas supply. We report a molecular outflow launched from a dust-rich star-forming galaxy at redshift 5.3, 1 billion years after the Big Bang. The outflow reaches velocities up to 800 kilometers per second relative to the galaxy, is resolved into multiple clumps, and carries mass at a rate within a factor of 2 of the star formation rate. Our results show that molecular outflows can remove a large fraction of the gas available for star formation from galaxies at high redshift.

6.
Nature ; 561(7721): E2, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29930351

RESUMEN

Change history: In this Letter, the Acknowledgements section should have included the following sentence: "The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.". This omission has been corrected online.

7.
Nature ; 556(7702): 469-472, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29695849

RESUMEN

Massive galaxy clusters have been found that date to times as early as three billion years after the Big Bang, containing stars that formed at even earlier epochs1-3. The high-redshift progenitors of these galaxy clusters-termed 'protoclusters'-can be identified in cosmological simulations that have the highest overdensities (greater-than-average densities) of dark matter4-6. Protoclusters are expected to contain extremely massive galaxies that can be observed as luminous starbursts 7 . However, recent detections of possible protoclusters hosting such starbursts8-11 do not support the kind of rapid cluster-core formation expected from simulations 12 : the structures observed contain only a handful of starbursting galaxies spread throughout a broad region, with poor evidence for eventual collapse into a protocluster. Here we report observations of carbon monoxide and ionized carbon emission from the source SPT2349-56. We find that this source consists of at least 14 gas-rich galaxies, all lying at redshifts of 4.31. We demonstrate that each of these galaxies is forming stars between 50 and 1,000 times more quickly than our own Milky Way, and that all are located within a projected region that is only around 130 kiloparsecs in diameter. This galaxy surface density is more than ten times the average blank-field value (integrated over all redshifts), and more than 1,000 times the average field volume density. The velocity dispersion (approximately 410 kilometres per second) of these galaxies and the enormous gas and star-formation densities suggest that this system represents the core of a cluster of galaxies that was already at an advanced stage of formation when the Universe was only 1.4 billion years old. A comparison with other known protoclusters at high redshifts shows that SPT2349-56 could be building one of the most massive structures in the Universe today.

8.
Nature ; 553(7686): 51-54, 2018 01 04.
Artículo en Inglés | MEDLINE | ID: mdl-29211721

RESUMEN

According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field. Observing these structures during their period of active growth and assembly-the first few hundred million years of the Universe-is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far. Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey. High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe. These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.

9.
BMC Res Notes ; 10(1): 711, 2017 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-29212545

RESUMEN

OBJECTIVES: The aim of this systematic review and meta-analysis was to perform an updated investigation of the effects of depression and anxiety on pregnancy outcomes following assisted reproductive technologies. A bibliographic search was performed using PubMed, PsycINFO, Embase, Science Direct databases. Data retrieved were analysed using a random effects model to estimate standardised mean differences. RESULTS: Of the 22 included studies, 18 investigated depression, 15 state anxiety, and seven trait anxiety. Data from 4018 patients were included in the meta-analysis. Results indicated that women who achieved pregnancy or a live birth reported lower levels of depression pre-treatment than those who did not, although the effects were small d = - 0.177 (95% CI - 0.327 to - 0.027, z = 2.309, p = 0.021). These results were consistent under different methodological conditions and the quality of these observational were graded as satisfactory. A similar pattern was seen for state (d = - 0.096, 95% CI - 0.180 to - 0.012: z = 2.241, p = 0.025) and trait anxiety (d = -  0.188, 95% CI - 0.007 to 0.356, z = 2.181, p = 0.029). More research is needed to investigate the impact of psychological variables on assisted reproductive technologies outcomes and moderator influences during assisted reproductive technologies processes.


Asunto(s)
Técnicas Reproductivas Asistidas , Ansiedad , Depresión , Femenino , Humanos , Embarazo , Resultado del Embarazo
10.
Phys Rev Lett ; 118(18): 185001, 2017 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-28524672

RESUMEN

A fast Alfvén wave with a finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer midplane plasma, where a population inversion of the energy distribution of fusion-born ions is observed to arise naturally. Fully nonlinear first-principles simulations, which self-consistently evolve particles and fields under the Maxwell-Lorentz system, demonstrate this novel "α-particle channeling" scenario for the first time.

11.
Phys Rev Lett ; 118(10): 105001, 2017 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-28339218

RESUMEN

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P_{ICE} scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n_{α}/n_{i}, of fusion born alpha particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a long-standing question in the physics of fusion alpha-particle confinement and stability in magnetic confinement fusion plasmas. It confirms the magnetoacoustic cyclotron instability as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.

12.
J Exp Bot ; 67(15): 4523-34, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27312669

RESUMEN

Early vigour is an important physiological trait to improve establishment, water-use efficiency, and grain yield for wheat. Phenotyping large numbers of lines is challenging due to the fast growth and development of wheat seedlings. Here we developed a new photo-based workflow to monitor dynamically the growth and development of the wheat canopy of two wheat lines with a contrasting early vigour trait. Multiview images were taken using a 'vegetation stress' camera at 2 d intervals from emergence to the sixth leaf stage. Point clouds were extracted using the Multi-View Stereo and Structure From Motion (MVS-SFM) algorithm, and segmented into individual organs using the Octree method, with leaf midribs fitted using local polynomial function. Finally, phenotypic parameters were calculated from the reconstructed point cloud including: tiller and leaf number, plant height, Haun index, phyllochron, leaf length, angle, and leaf elongation rate. There was good agreement between the observed and estimated leaf length (RMSE=8.6mm, R (2)=0.98, n=322) across both lines. Significant contrasts of phenotyping parameters were observed between the two lines and were consistent with manual observations. The early vigour line had fewer tillers (2.4±0.6) and larger leaves (308.0±38.4mm and 17.1±2.7mm for leaf length and width, respectively). While the phyllochron of both lines was quite similar, the non-vigorous line had a greater Haun index (more leaves on the main stem) on any date, as the vigorous line had slower development of its first two leaves. The workflow presented in this study provides an efficient method to phenotype individual plants using a low-cost camera (an RGB camera is also suitable) and could be applied in phenotyping for applications in both simulation modelling and breeding. The rapidity and accuracy of this novel method can characterize the results of specific selection criteria (e.g. width of leaf three, number of tillers, rate of leaf appearance) that have been or can now be utilized to breed for early leaf growth and tillering in wheat.


Asunto(s)
Triticum/crecimiento & desarrollo , Producción de Cultivos , Estudios de Asociación Genética , Genotipo , Imagenología Tridimensional , Fotograbar , Hojas de la Planta/anatomía & histología , Hojas de la Planta/crecimiento & desarrollo , Semillas/crecimiento & desarrollo , Triticum/anatomía & histología , Triticum/genética
13.
Clin Endocrinol (Oxf) ; 84(5): 664-71, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26641418

RESUMEN

OBJECTIVE: Appropriate self-management of glucocorticoid therapy (GC) is crucial for patients with adrenal insufficiency (AI). We aimed to describe patients' self-reported nonadherence to GC, evaluate perceived doubts about need for GC, concerns about adverse effects, and dissatisfaction with information received about GC. DESIGN: Cross-sectional survey. PATIENTS: Patients prescribed GC for AI (n = 81) from five European countries. MEASUREMENTS: Online survey including the Medication Adherence Report Scale (MARS), Beliefs about Medicines Questionnaire(©) (BMQ Specific, adapted for AI) and Satisfaction with Information about Medicines Scale(©) (Prof Rob Horne; SIMS). RESULTS: Most patients (85·2%) reported a degree of nonadherence to GC. The most frequent types of nonadherence concerned changing the timing of GC doses, for example taking a dose later in the day than advised (37·0%). Few patients doubted their personal need for daily GC, but most reported high concerns about GC including potential weight gain (50·6%), osteoporosis (53·6%) and the continuing risk of adrenal crisis (50·6%). Dissatisfaction with information about GC was frequent, with participants particularly dissatisfied with the amount of information they had received about potential problems with GC. People who expressed dissatisfaction with information about GC, and concerns about its adverse effects were also more likely to report nonadherence (P < 0·05). CONCLUSIONS: Nonadherence to treatment, concerns about potential adverse effects and dissatisfaction with the information provided about treatment were frequently reported by this European sample of AI patients. Many AI patients may need additional information about their GC and support to address concerns about GC and facilitate adherence.


Asunto(s)
Insuficiencia Suprarrenal/tratamiento farmacológico , Glucocorticoides/uso terapéutico , Cumplimiento de la Medicación/estadística & datos numéricos , Satisfacción del Paciente/estadística & datos numéricos , Encuestas y Cuestionarios , Adulto , Distribución de Chi-Cuadrado , Estudios Transversales , Europa (Continente) , Femenino , Glucocorticoides/administración & dosificación , Glucocorticoides/efectos adversos , Humanos , Internet , Masculino , Persona de Mediana Edad , Osteoporosis/etiología , Evaluación de Resultado en la Atención de Salud/métodos , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Aumento de Peso
14.
Phys Rev Lett ; 114(12): 125004, 2015 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-25860751

RESUMEN

Recent measurements of microwave and x-ray emission during edge localized mode (ELM) activity in tokamak plasmas provide a fresh perspective on ELM physics. It is evident that electron kinetics, which are not incorporated in standard (fluid) models for the instability that drives ELMs, play a key role in the new observations. These effects should be included in future models for ELMs and the ELM cycle. The observed radiative effects paradoxically imply acceleration of electrons parallel to the magnetic field combined with rapid acquisition of perpendicular momentum. It is shown that this paradox can be resolved by the action of the anomalous Doppler instability which enables fast collective radiative relaxation, in the perpendicular direction, of electrons accelerated in the parallel direction by inductive electric fields generated by the initial ELM instability.

15.
Epilepsy Behav ; 31: 312-20, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24290250

RESUMEN

BACKGROUND: Nonadherence to antiepileptic drugs (AEDs) can result in suboptimal outcomes for patients. AIM: This study aimed to assess the utility of a theory-based approach to understanding patient perspectives on AEDs and adherence. METHOD: Patients with epilepsy, identified by a GP case note review, were mailed validated questionnaires assessing their perceptions of AEDs and their adherence to them. RESULTS: Most (84.9%) of the 398 AED-treated respondents accepted the necessity of AEDs, but over half expressed doubts, with 55% disagreeing or uncertain about the statement 'I would prefer to take epilepsy medication than risk a seizure'. Over a third (36.4%) expressed strong concerns about the potential negative effects of AEDs. We used self-report and medication possession ratio to classify 36.4% of patients as nonadherent. Nonadherence was related to beliefs about medicines and implicit attitudes toward AEDs (p<0.05). Adherence-related attitudes toward AEDs were correlated with general beliefs about pharmaceuticals (BMQ General: General Harm, General Overuse, and General Benefit scales) and perceptions of personal sensitivity to medicines (PSM scale). CONCLUSION: We identified salient, adherence-related beliefs about AEDs. Patient-centered interventions to support medicine optimization for people with epilepsy should take account of these beliefs.


Asunto(s)
Anticonvulsivantes/uso terapéutico , Cultura , Epilepsia/tratamiento farmacológico , Cumplimiento de la Medicación/psicología , Atención Primaria de Salud , Adulto , Anciano , Epilepsia/epidemiología , Epilepsia/psicología , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Persona de Mediana Edad , Percepción , Índice de Severidad de la Enfermedad , Reino Unido/epidemiología
16.
Phys Rev Lett ; 111(20): 201101, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24289672

RESUMEN

The first observed connection between kinetic instabilities driven by proton temperature anisotropy and estimated energy cascade rates in the turbulent solar wind is reported using measurements from the Wind spacecraft at 1 AU. We find enhanced cascade rates are concentrated along the boundaries of the (ß∥, T⊥/T∥) plane, which includes regions theoretically unstable to the mirror and firehose instabilities. A strong correlation is observed between the estimated cascade rate and kinetic effects such as temperature anisotropy and plasma heating, resulting in protons 5-6 times hotter and 70%-90% more anisotropic than under typical isotropic plasma conditions. These results offer new insights into kinetic processes in a turbulent regime.

17.
J Exp Bot ; 64(11): 3439-51, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23873998

RESUMEN

Small or shrivelled wheat kernels (screenings) that reduce crop value are commonly produced in terminal drought environments. The aim of this study was to establish whether the incorporation of the tiller inhibition (tin) gene would contribute to maintenance of kernel weight and reductions in screenings under terminal water deficit. Five Silverstar near-isogenic lines contrasting in high and low tiller potential and their recurrent Silverstar parent were established at two plant densities under managed terminal water deficit (mild and severe) and irrigated conditions. With irrigation (grain yield of 5.6 t ha(-1)), kernels of all lines weighed ~31 mg, with restricted-tillering (R-tin) lines producing an average 15% lower grain yield. Under both mild and severe terminal water deficit (4.1 t ha(-1) and 2.8 t ha(-1)), free-tillering lines had relatively high screenings ranging from 11.9% to 16.2%. Compared with free-tillering lines, R-tin lines maintained large kernel weight (~29 mg kernel(-1)) and had 29% and 51% fewer screenings under the two stresses, and a significantly greater (+11%) grain yield under mild stress. Higher kernel weights in tin lines were realized even with the greater kernel number per spike. The higher kernel weight of the R-tin lines under stress conditions was associated with greater anthesis biomass and increased stem water-soluble carbohydrates, ensuring more assimilate for later translocation to filling grain. The incorporation of the tin gene into genetic material adapted to the target environments provides scope for improvement in both grain yield and kernel weight, and a reduction in screenings in terminal water deficit environments.


Asunto(s)
Grano Comestible/crecimiento & desarrollo , Grano Comestible/metabolismo , Proteínas de Plantas/metabolismo , Triticum/crecimiento & desarrollo , Triticum/metabolismo , Temperatura
18.
Nature ; 498(7454): 338-41, 2013 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-23698363

RESUMEN

Stellar archaeology shows that massive elliptical galaxies formed rapidly about ten billion years ago with star-formation rates of above several hundred solar masses per year. Their progenitors are probably the submillimetre bright galaxies at redshifts z greater than 2. Although the mean molecular gas mass (5 × 10(10) solar masses) of the submillimetre bright galaxies can explain the formation of typical elliptical galaxies, it is inadequate to form elliptical galaxies that already have stellar masses above 2 × 10(11) solar masses at z ≈ 2. Here we report multi-wavelength high-resolution observations of a rare merger of two massive submillimetre bright galaxies at z = 2.3. The system is seen to be forming stars at a rate of 2,000 solar masses per year. The star-formation efficiency is an order of magnitude greater than that of normal galaxies, so the gas reservoir will be exhausted and star formation will be quenched in only around 200 million years. At a projected separation of 19 kiloparsecs, the two massive starbursts are about to merge and form a passive elliptical galaxy with a stellar mass of about 4 × 10(11) solar masses. We conclude that gas-rich major galaxy mergers with intense star formation can form the most massive elliptical galaxies by z ≈ 1.5.

19.
Philos Trans A Math Phys Eng Sci ; 371(1991): 20120287, 2013 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-23588048

RESUMEN

Climate sensitivity is commonly taken to refer to the equilibrium change in the annual mean global surface temperature following a doubling of the atmospheric carbon dioxide concentration. Evaluating this variable remains of significant scientific interest, but its global nature makes it largely irrelevant to many areas of climate science, such as impact assessments, and also to policy in terms of vulnerability assessments and adaptation planning. Here, we focus on local changes and on the way observational data can be analysed to inform us about how local climate has changed since the middle of the nineteenth century. Taking the perspective of climate as a constantly changing distribution, we evaluate the relative changes between different quantiles of such distributions and between different geographical locations for the same quantiles. We show how the observational data can provide guidance on trends in local climate at the specific thresholds relevant to particular impact or policy endeavours. This also quantifies the level of detail needed from climate models if they are to be used as tools to assess climate change impact. The mathematical basis is presented for two methods of extracting these local trends from the data. The two methods are compared first using surrogate data, to clarify the methods and their uncertainties, and then using observational surface temperature time series from four locations across Europe.

20.
Nature ; 496(7445): 329-33, 2013 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-23598341

RESUMEN

Massive present-day early-type (elliptical and lenticular) galaxies probably gained the bulk of their stellar mass and heavy elements through intense, dust-enshrouded starbursts--that is, increased rates of star formation--in the most massive dark-matter haloes at early epochs. However, it remains unknown how soon after the Big Bang massive starburst progenitors exist. The measured redshift (z) distribution of dusty, massive starbursts has long been suspected to be biased low in z owing to selection effects, as confirmed by recent findings of systems with redshifts as high as ~5 (refs 2-4). Here we report the identification of a massive starburst galaxy at z = 6.34 through a submillimetre colour-selection technique. We unambiguously determined the redshift from a suite of molecular and atomic fine-structure cooling lines. These measurements reveal a hundred billion solar masses of highly excited, chemically evolved interstellar medium in this galaxy, which constitutes at least 40 per cent of the baryonic mass. A 'maximum starburst' converts the gas into stars at a rate more than 2,000 times that of the Milky Way, a rate among the highest observed at any epoch. Despite the overall downturn in cosmic star formation towards the highest redshifts, it seems that environments mature enough to form the most massive, intense starbursts existed at least as early as 880 million years after the Big Bang.

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