Galaxy evolution. Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang.

Most present-day galaxies with stellar masses ≥10(11) solar masses show no ongoing star formation and are dense spheroids. Ten billion years ago, similarly massive galaxies were typically forming stars at rates of hundreds solar masses per year. It is debated how star formation ceased, on which time scales, and how this "quenching" relates to the emergence of dense spheroids. We measured stellar mass and star-formation rate surface density distributions in star-forming galaxies at redshift 2.2 with ~1-kiloparsec resolution. We find that, in the most massive galaxies, star formation is quenched from the inside out, on time scales less than 1 billion years in the inner regions, up to a few billion years in the outer disks. These galaxies sustain high star-formation activity at large radii, while hosting fully grown and already quenched bulges in their cores.

A test of the nature of cosmic acceleration using galaxy redshift distortions.

Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the equations of cosmic expansion, accounting for about 75 per cent of the total energy density in the Universe. The simplest option for this 'dark energy' corresponds to a 'cosmological constant', perhaps related to the quantum vacuum energy. Physically viable alternatives invoke either the presence of a scalar field with an evolving equation of state, or extensions of general relativity involving higher-order curvature terms or extra dimensions. Although they produce similar expansion rates, different models predict measurable differences in the growth rate of large-scale structure with cosmic time. A fingerprint of this growth is provided by coherent galaxy motions, which introduce a radial anisotropy in the clustering pattern reconstructed by galaxy redshift surveys. Here we report a measurement of this effect at a redshift of 0.8. Using a new survey of more than 10,000 faint galaxies, we measure the anisotropy parameter beta = 0.70 +/- 0.26, which corresponds to a growth rate of structure at that time of f = 0.91 +/- 0.36. This is consistent with the standard cosmological-constant model with low matter density and flat geometry, although the error bars are still too large to distinguish among alternative origins for the accelerated expansion. The correct origin could be determined with a further factor-of-ten increase in the sampled volume at similar redshift.

Giant-cell arteritis of the female genital tract associated with occult temporal arteritis and FDG-PET evidence of large-vessel vasculitis.

We describe a case of giant cell arteritis (GCA) of the female genital tract. Fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and CT-scan showed evidence of large-vessel vasculitis involving the thoracic aorta and its branches, while temporal artery biopsy showed arteritis despite the absence of clinical manifestations suggestive of GCA. We review the literature and discuss the relationship between "cranial" GCA, large-vessel GCA and female genital GCA.

A large population of galaxies 9 to 12 billion years back in the history of the Universe.

To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4.

Old galaxies in the young Universe.

More than half of all stars in the local Universe are found in massive spheroidal galaxies, which are characterized by old stellar populations with little or no current star formation. In present models, such galaxies appear rather late in the history of the Universe as the culmination of a hierarchical merging process, in which larger galaxies are assembled through mergers of smaller precursor galaxies. But observations have not yet established how, or even when, the massive spheroidals formed, nor if their seemingly sudden appearance when the Universe was about half its present age (at redshift z approximately 1) results from a real evolutionary effect (such as a peak of mergers) or from the observational difficulty of identifying them at earlier epochs. Here we report the spectroscopic and morphological identification of four old, fully assembled, massive (10(11) solar masses) spheroidal galaxies at l.6 < z < 1.9, the most distant such objects currently known. The existence of such systems when the Universe was only about one-quarter of its present age shows that the build-up of massive early-type galaxies was much faster in the early Universe than has been expected from theoretical simulations.

Association between HLA genes and susceptibility to toluene diisocyanate-induced asthma.

BACKGROUND: Only a small proportion of subjects exposed to isocyanates develop occupational asthma, suggesting individual predisposition. The human leucocyte antigen (HLA) class II molecules may play a crucial role in the development of the immune response to isocyanates. OBJECTIVES: To investigate the role of HLA class II molecules in the development of toluene diisocyanate (TDI)-induced asthma. SUBJECTS: Sixty-seven asthmatic subjects and 27 asymptomatic exposed subjects (controls) were typed at the HLA class II DQA1, DQB1 and DRB1 loci by polymerase chain reaction (PCR)-based techniques. RESULTS: The frequencies of DQA1*0104 and DQB1*0503 were significantly increased in asthmatics compared with asymptomatic exposed subjects, while DQA1*0101 and DQB1*0501 were significantly increased in asymptomatic exposed subjects. No significant difference was found in the distribution of DRB1 alleles between asthmatics and controls. CONCLUSIONS: The results of this study indicate that HLA-regulated immune mechanisms are involved in TDI-induced asthma and that, in exposed subjects, specific factors may increase or decrease the risk of developing disease.

Use of 3'HVR genomic probe for presymptomatic diagnosis of adult polycystic kidney disease in northern Italy: comparison of DNA analysis and renal ultrasonographic data.

A highly polymorphic DNA probe (3'HVR) with genetic linkage to the locus of autosomal dominant polycystic kidney disease was used for screening. Families with subjects at risk were from the Po river delta region (Northern Italy), where the disease accounts for 24% of the demands for dialysis. 3'HVR alleles were investigated in white blood cell DNA from 142 members of 18 families. The genomic marker was found informative in 88% of cases. Two recombinations between the marker and the disease locus were observed in 79 meioses. In 42 of the subjects at risk the results of DNA analysis and renal ultrasonography were compared. In 36 subjects the tests confirmed each other (18 were positive). In the other six subjects (all under 20 years of age and four under 10) only DNA analysis could diagnose the inheritance of cystic disease in the absence of demonstrable cysts. The findings indicate that in the population of the Po river delta the presymptomatic detection of adult polycystic kidney disease by 3'HVR linkage analysis is feasible in 88% of cases with approximately 95% reliability.