Quasars and their host galaxies

This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers. Black hole mass estimates for quasars, and our confidence in them, have improved significantly, allowing a start on relating quasar properties such as radio jet power to fundamental parameters of the quasar such as black hole mass and accretion rate. Quasar host galaxy studies have allowed us to find and characterize the host galaxies of quasars to z>2. Despite these developments, many questions remain unresolved, in particular the origin of the close relationship between black hole mass and galaxy bulge mass/velocity dispersion seen in local galaxies.Comment: Review article, to appear in Astrophysics Update

What is the Oxygen Isotope Composition of Venus? The Scientific Case for Sample Return from Earth’s “Sister” Planet

Venus is Earth’s closest planetary neighbour and both bodies are of similar size and mass. As a consequence, Venus is often described as Earth’s sister planet. But the two worlds have followed very different evolutionary paths, with Earth having benign surface conditions, whereas Venus has a surface temperature of 464 °C and a surface pressure of 92 bar. These inhospitable surface conditions may partially explain why there has been such a dearth of space missions to Venus in recent years.The oxygen isotope composition of Venus is currently unknown. However, this single measurement (Δ17O) would have first order implications for our understanding of how large terrestrial planets are built. Recent isotopic studies indicate that the Solar System is bimodal in composition, divided into a carbonaceous chondrite (CC) group and a non-carbonaceous (NC) group. The CC group probably originated in the outer Solar System and the NC group in the inner Solar System. Venus comprises 41% by mass of the inner Solar System compared to 50% for Earth and only 5% for Mars. Models for building large terrestrial planets, such as Earth and Venus, would be significantly improved by a determination of the Δ17O composition of a returned sample from Venus. This measurement would help constrain the extent of early inner Solar System isotopic homogenisation and help to identify whether the feeding zones of the terrestrial planets were narrow or wide.Determining the Δ17O composition of Venus would also have significant implications for our understanding of how the Moon formed. Recent lunar formation models invoke a high energy impact between the proto-Earth and an inner Solar System-derived impactor body, Theia. The close isotopic similarity between the Earth and Moon is explained by these models as being a consequence of high-temperature, post-impact mixing. However, if Earth and Venus proved to be isotopic clones with respect to Δ17O, this would favour the classic, lower energy, giant impact scenario.We review the surface geology of Venus with the aim of identifying potential terrains that could be targeted by a robotic sample return mission. While the potentially ancient tessera terrains would be of great scientific interest, the need to minimise the influence of venusian weathering favours the sampling of young basaltic plains. In terms of a nominal sample mass, 10 g would be sufficient to undertake a full range of geochemical, isotopic and dating studies. However, it is important that additional material is collected as a legacy sample. As a consequence, a returned sample mass of at least 100 g should be recovered.Two scenarios for robotic sample return missions from Venus are presented, based on previous mission proposals. The most cost effective approach involves a “Grab and Go” strategy, either using a lander and separate orbiter, or possibly just a stand-alone lander. Sample return could also be achieved as part of a more ambitious, extended mission to study the venusian atmosphere. In both scenarios it is critical to obtain a surface atmospheric sample to define the extent of atmosphere-lithosphere oxygen isotopic disequilibrium. Surface sampling would be carried out by multiple techniques (drill, scoop, “vacuum-cleaner” device) to ensure success. Surface operations would take no longer than one hour.Analysis of returned samples would provide a firm basis for assessing similarities and differences between the evolution of Venus, Earth, Mars and smaller bodies such as Vesta. The Solar System provides an important case study in how two almost identical bodies, Earth and Venus, could have had such a divergent evolution. Finally, Venus, with its runaway greenhouse atmosphere, may provide data relevant to the understanding of similar less extreme processes on Earth. Venus is Earth’s planetary twin and deserves to be better studied and understood. In a wider context, analysis of returned samples from Venus would provide data relevant to the study of exoplanetary systems

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd

The nickel hyperaccumulator plant Alyssum bertolonii as a potential agent for phytoremediation and phytomining of nickel

Experiments were carried out in Italy on the potential use of the hyperaccumulator Alyssum bertolonii in phytomining of ultramafic soils for Ni. In situ experimental plots at Murlo, Tuscany were fertilized with various regimes during a 2-year period. The best fertilizer treatment (N 4- K 4- P) gave a threefold increase of the biomass of reproductive matter to 9.0 t/ha without dilution of the unfertilized Ni content. A Ni content of 0.8% in dry matter (11% in ash), would give a Ni yield of 72 kg/ha without need of resowing for a further crop. There was no correlation between the age of a plant and its Ni content. The long-term cropping sustainability of the soils was simulated by sequential extractions with KH phthalate solutions at pH 2, 4 and 6 that showed a limiting available Ni content of 768 μg/g. Thus just over seven croppings at pH 6 in the rhizosphere would reduce the available Ni pool by 30%. A proposed model for phytomining involves harvesting the crop after 12 months and burning the material to produce a sulphur-free bio-ore with about 11% Ni. Utilising the energy of combustion is also discussed. It is considered that Alyssum bertolonii or other Alyssum species might be used for phytomining throughout the Mediterranean area including Anatolia, as well as in Western Australia and the western United States. The economic limits of phytomining are proposed and at current world prices, the technique would only be feasible for Ni and Co with plants of at least the same biomass as Alyssum. Plants of higher biomass and similar uptake potential as for Ni, could extend the limits to other elements

Spin-dependent transport in organic-ferromagnets

Based on the modified Su-Schrieffer-Heeger model and the non-equilibrium Green's function current formula, the spin polarization of the ferromagnet-electrode connected organic ferromagnet is theoretically studied. The spin polarization can be suppressed by atomic dimerization and be driven by an applied electric field. We investigate the spin polarization from the viewpoint of energy competitions in different interactions under the electric field. In addition, the ferromagnetic electrodes significantly enhance the spin polarization

Virtual Reality and Serious Games in Healthcare

This chapter discusses the applications and solutions of emerging Virtual Reality (VR) and video games technologies in the healthcare sector, e.g. physical therapy for motor rehabilitation, exposure therapy for psychological phobias, and pain relief. Section 2 reviews state-of-the-art interactive devices used in current VR systems and high-end games such as sensor-based and camera-based tracking devices, data gloves, and haptic force feedback devices. Section 3 investigates recent advances and key concepts in games technology, including dynamic simulation, flow theory, adaptive games, and their possible implementation in serious games for healthcare. Various serious games are described in this section: some were designed and developed for specific healthcare purposes, e.g. BreakAway (2009)’s Free Dive, HopeLab (2006)’s Re-Mission, and Ma et al. (2007)’s VR game series, others were utilising off-the-shelf games such as Nintendo Wii sports for physiotherapy. A couple of experiments of using VR systems and games for stroke rehabilitation are highlighted in section 4 as examples to showcase the benefits and impacts of these technologies to conventional clinic practice. Finally, section 5 points some future directions of applying emerging games technologies in healthcare, such as augmented reality, Wii-mote motion control system, and even full body motion capture and controller free games technology demonstrated recently on E3 2009 which have great potentials to treat motor disorders, combat obesity, and other healthcare applications