The physical constraints on a new LoBAL QSO at z=4.82

Very few low-ionization broad absorption line (LoBAL) QSOs have been found at high redshifts to date. One high-redshift LoBAL QSO, J0122+1216, was recently discovered at the Lijiang 2.4-m Telescope with an initial redshift determination of 4.76. Aiming to investigate its physical properties, we carried out follow-up observations in the optical and near-IR spectroscopy. Near-IR spectra from UKIRT and P200 confirms that it is a LoBAL, with a new redshift determination of $4.82\pm0.01$ based on the \mgii~ emission-line. The new \mgii~ redshift determination reveals strong blueshifts and asymmetry of the high-ionization emission lines. We estimated a black hole mass of $\sim 2.3\times 10^9 M_\odot$ and Eddington ratio of $\sim 1.0$ according to the empirical \mgii-based single-epoch relation and bolometric correction factor. It is possible that strong outflows are the result of an extreme quasar environment driven by the high Eddington ratio. A lower limit on the outflowing kinetic power ($>0.9\% L_{Edd}$) was derived from both emission and absorption lines, indicating these outflows play a significant role in the feedback process to regulate the growth of its black hole as well as host galaxy evolution.Comment: 12 pages, 10 figures. Accepted for publication in The Astrophysical Journa

The Neutrophil's Eye-View: Inference and Visualisation of the Chemoattractant Field Driving Cell Chemotaxis In Vivo

As we begin to understand the signals that drive chemotaxis in vivo, it is becoming clear that there is a complex interplay of chemotactic factors, which changes over time as the inflammatory response evolves. New animal models such as transgenic lines of zebrafish, which are near transparent and where the neutrophils express a green fluorescent protein, have the potential to greatly increase our understanding of the chemotactic process under conditions of wounding and infection from video microscopy data. Measurement of the chemoattractants over space (and their evolution over time) is a key objective for understanding the signals driving neutrophil chemotaxis. However, it is not possible to measure and visualise the most important contributors to in vivo chemotaxis, and in fact the understanding of the main contributors at any particular time is incomplete. The key insight that we make in this investigation is that the neutrophils themselves are sensing the underlying field that is driving their action and we can use the observations of neutrophil movement to infer the hidden net chemoattractant field by use of a novel computational framework. We apply the methodology to multiple in vivo neutrophil recruitment data sets to demonstrate this new technique and find that the method provides consistent estimates of the chemoattractant field across the majority of experiments. The framework that we derive represents an important new methodology for cell biologists investigating the signalling processes driving cell chemotaxis, which we label the neutrophils eye-view of the chemoattractant field

Modeling regional transportation demand in China and the impacts of a national carbon constraint

Climate and energy policy in China will have important and uneven impacts on the country’s regionally heterogeneous transport system. In order to simulate these impacts, transport sector detail is added to a multi-sector, static, global computable general equilibrium (CGE) model which resolves China’s provinces as distinct regions. This framework is used to perform an analysis of national-level greenhouse gas (GHG) policies. Freight, commercial passenger and household (private vehicle) transport are separately represented, with the former two categories further disaggregated into road and non-road modes. The preparation of model inputs is described, including assembly of a provincial transport data set from publicly-available statistics. Two policies are analyzed: the first represents China’s target of a 17% reduction in GHG emissions intensity of GDP during the Twelfth Five Year Plan (12FYP), and the second China’s Copenhagen target of a 40–45% reduction in the same quantity during the period 2005–2020. We find significant heterogeneity in regional transport impacts. We find that both freight and passenger transportation in some of the poorest provinces that rely heavily on energy-intensive resource and raw materials exports are most adversely affected, as they offer many of the least cost abatement opportunities and the transformation of their energy systems strongly affects transport demand. At the national level, we find that of all the transport-related sectors, road freight transport activity is affected most by policy, likely due to its high energy intensity and limited low cost opportunities for improving efficiency. The type and degree of regional disparity in impacts is relevant to central and provincial government decisions which set and allocate climate, energy and transport policy targets. We describe how this research establishes a basis for further regional CGE analyses of the economic, energy and environmental impacts of transport-focused policies including vehicle ownership restrictions, taxation of driving activity or fuels, and the supply of public transit