The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3

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 galaxies4 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

The bright-end galaxy candidates at z ~ 9 from 79 independent HST fields

We present a full data analysis of the pure-parallel Hubble Space Telescope (HST) imaging observations in the Brightest of Reionizing Galaxies Survey (BoRG[z9]) in Cycle 22. The medium-deep exposures with five HST/WFC3IR+UVIS filter bands from 79 independent sightlines (~370 arcmin^2) provide the least biased determination of number density for z>9 bright galaxies against cosmic variance. After a strict two-step selection for candidate galaxies, including dropout color and photometric redshift analyses, and revision of previous BoRG candidates, we identify one source at z~10 and two sources at z~9. The z~10 candidate shows evidence of line-of-sight lens magnification (mu~1.5), yet it appears surprisingly luminous (MUV ~ -22.6\pm0.3 mag), making it one of the brightest candidates at z > 8 known (~ 0.3 mag brighter than the z = 8.68 galaxy EGSY8p7, spectroscopically confirmed by Zitrin and collaborators). For z ~ 9 candidates, we include previous data points at fainter magnitudes and find that the data are well fitted by a Schechter luminosity function with alpha ~ -2.1, MUV ~ -21.5 mag, and log phi ~ -4.5 Mpc^-3mag^-1, for the first time without fixing any parameters. The inferred cosmic star formation rate density is consistent with unaccelerated evolution from lower redshift.Comment: 18pages, 7figures, 6tables. accepted to the Astrophysical Journa

Modeling effects of L-type ca(2+) current and na(+)-ca(2+) exchanger on ca(2+) trigger flux in rabbit myocytes with realistic T-tubule geometries.

The transverse tubular system of rabbit ventricular myocytes consists of cell membrane invaginations (t-tubules) that are essential for efficient cardiac excitation-contraction coupling. In this study, we investigate how t-tubule micro-anatomy, L-type Ca(2+) channel (LCC) clustering, and allosteric activation of Na(+)/Ca(2+) exchanger by L-type Ca(2+) current affects intracellular Ca(2+) dynamics. Our model includes a realistic 3D geometry of a single t-tubule and its surrounding half-sarcomeres for rabbit ventricular myocytes. The effects of spatially distributed membrane ion-transporters (LCC, Na(+)/Ca(2+) exchanger, sarcolemmal Ca(2+) pump, and sarcolemmal Ca(2+) leak), and stationary and mobile Ca(2+) buffers (troponin C, ATP, calmodulin, and Fluo-3) are also considered. We used a coupled reaction-diffusion system to describe the spatio-temporal concentration profiles of free and buffered intracellular Ca(2+). We obtained parameters from voltage-clamp protocols of L-type Ca(2+) current and line-scan recordings of Ca(2+) concentration profiles in rabbit cells, in which the sarcoplasmic reticulum is disabled. Our model results agree with experimental measurements of global Ca(2+) transient in myocytes loaded with 50 μM Fluo-3. We found that local Ca(2+) concentrations within the cytosol and sub-sarcolemma, as well as the local trigger fluxes of Ca(2+) crossing the cell membrane, are sensitive to details of t-tubule micro-structure and membrane Ca(2+) flux distribution. The model additionally predicts that local Ca(2+) trigger fluxes are at least threefold to eightfold higher than the whole-cell Ca(2+) trigger flux. We found also that the activation of allosteric Ca(2+)-binding sites on the Na(+)/Ca(2+) exchanger could provide a mechanism for regulating global and local Ca(2+) trigger fluxes in vivo. Our studies indicate that improved structural and functional models could improve our understanding of the contributions of L-type and Na(+)/Ca(2+) exchanger fluxes to intracellular Ca(2+) dynamics

Automated NDT of floating production storage oil tanks with a swimming and climbing robot

This paper describes the design and development of a prototype swimming and wall-climbing robot that gains access to internal tank wall and floor surfaces on Floating Production Storage Oil (FPSO) tanks for the purposes of carrying out Non-Destructive Testing (NDT) of welds while the tank is in-service and full of oil. A brief description is given of the inspection environment and the three NDT techniques (ultrasonic phased arrays, eddy current arrays, and Alternating Current Field Measurement ACFM arrays) that will be used to detect weld cracks and floor corrosion and pitting. © 2006 Springer-Verlag Berlin Heidelberg

Phosphine-imine and-enamido ligands for acceptorless dehydrogenation catalysis

A highly tunable phosphine-imine ligand family is introduced. Following metallation with ruthenium, deprotonation of the ligand affords a phosphine-enamido species. Complexes with the ligand in both the imine and enamido forms are active toward acceptorless dehydrogenation reactions

Development of a novel 3D immersive visualisation tool for manual image matching

© Cambridge University Press 2019. Aim:The novel Volumetric Image Matching Environment for Radiotherapy (VIMER) was developed to allow users to view both computed tomography (CT) and cone-beam CT (CBCT) datasets within the same 3D model in virtual reality (VR) space. Stereoscopic visualisation of both datasets combined with custom slicing tools and complete freedom in motion enables alternative inspection and matching of the datasets for image-guided radiotherapy (IGRT).Material and methods:A qualitative study was conducted to explore the challenges and benefits of VIMER with respect to image registration. Following training and use of the software, an interview session was conducted with a sample group of six university staff members with clinical experience in image matching.Results:User discomfort and frustration stemmed from unfamiliarity with the drastically different input tools and matching interface. As the primary advantage, the users reported match inspection efficiency when presented with the 3D volumetric renderings of the planning and secondary CBCT datasets.Findings:This study provided initial evidence for the achievable benefits and limitations to consider when implementing a 3D voxel-based dataset comparison VR tool including a need for extensive training and the minimal interruption to IGRT workflow. Key advantages include efficient 3D anatomical interpretation and the capability for volumetric matching

The past, present and future of plant nematology in International Agricultural Research Centres

This article reviews the plant parasitic nematodes of the major mandate crops of the International Agricultural Research Centres, which include 19 of the world's key staple crops such as rice, wheat, maize, potato, barley, root crops and grain legumes, and discusses the problems faced by those working in plant nematology around the world. It emphasises the damage caused by plant parasitic nematodes; nematologists have estimated that they cause crop yield losses at nearly 9% in the developed world and at over 14% in developing countries. Despite this, the authors argue that plant nematology is a sorely neglected science within the IARCs, with the number of nematologists remaining static over the last 20 years, while staff numbers overall have increased by 250% in the same perio