1,177 research outputs found
The MAGIC of CINEMA: First in-flight science results from a miniaturised anisotropic magnetoresistive magnetometer
We present the first in-flight results from a novel miniaturised anisotropic
magnetoresistive space magnetometer, MAGIC (MAGnetometer from Imperial
College), aboard the first CINEMA (CubeSat for Ions, Neutrals, Electrons
and MAgnetic fields) spacecraft in low Earth orbit. An attitude-independent
calibration technique is detailed using the International Geomagnetic
Reference Field (IGRF), which is temperature dependent in the case of the
outboard sensor. We show that the sensors accurately measure
the expected absolute field to within 2% in attitude mode and 1%
in science mode. Using a simple method we are able to estimate the
spacecraft's attitude using the magnetometer only, thus characterising
CINEMA's spin, precession and nutation. Finally, we show that the
outboard sensor is capable of detecting transient physical signals
with amplitudes of ~ 20–60 nT. These include field-aligned currents
at the auroral oval, qualitatively similar to previous observations,
which agree in location with measurements from the DMSP
(Defense Meteorological Satellite Program) and POES
(Polar-orbiting Operational Environmental Satellites) spacecraft.
Thus, we demonstrate and discuss the potential science capabilities
of the MAGIC instrument onboard a CubeSat platform
Looking for life on Mars with the Rosalind Franklin rover: the PanCam instrument
The ESA-Russia Rosalind Franklin (ExoMars 2022) rover, with its unique 2m drill, will address key questions in the search for life on Mars. PanCam will establish the surface context, with other instruments, providing geology, atmospheric science and 3D vision. PanCam uses a pair of Wide Angle Cameras (WACs), each with an 11 position filter wheel, and a High Resolution Camera (HRC). The cameras and electronics are in an optical bench that provides the interface to the rover and planetary protection. PanCam includes a calibration target mounted on the rover deck for radiometric calibration, fiducial markers for geometric calibration and a rover inspection mirror
Surface code quantum computing by lattice surgery
In recent years, surface codes have become a leading method for quantum error
correction in theoretical large scale computational and communications
architecture designs. Their comparatively high fault-tolerant thresholds and
their natural 2-dimensional nearest neighbour (2DNN) structure make them an
obvious choice for large scale designs in experimentally realistic systems.
While fundamentally based on the toric code of Kitaev, there are many variants,
two of which are the planar- and defect- based codes. Planar codes require
fewer qubits to implement (for the same strength of error correction), but are
restricted to encoding a single qubit of information. Interactions between
encoded qubits are achieved via transversal operations, thus destroying the
inherent 2DNN nature of the code. In this paper we introduce a new technique
enabling the coupling of two planar codes without transversal operations,
maintaining the 2DNN of the encoded computer. Our lattice surgery technique
comprises splitting and merging planar code surfaces, and enables us to perform
universal quantum computation (including magic state injection) while removing
the need for braided logic in a strictly 2DNN design, and hence reduces the
overall qubit resources for logic operations. Those resources are further
reduced by the use of a rotated lattice for the planar encoding. We show how
lattice surgery allows us to distribute encoded GHZ states in a more direct
(and overhead friendly) manner, and how a demonstration of an encoded CNOT
between two distance 3 logical states is possible with 53 physical qubits, half
of that required in any other known construction in 2D.Comment: Published version. 29 pages, 18 figure
Evidence of Hot Carrier Extraction in Metal Halide Perovskite Solar Cells
The presence of hot carriers is presented in the operational properties of an
(FA,Cs)Pb(I, Br, Cl)3 solar cell at ambient temperatures and under practical
solar concentration. At 100 K, clear evidence of hot carriers is observed in
both the high energy tail of the photoluminescence spectra and from the
appearance of a non-equilibrium photocurrent at higher fluence in light J-V
measurements. At room temperature, however, the presence of hot carriers in the
emission at elevated laser fluence are shown to compete with a gradual red
shift in the PL peak energy as photo induced halide segregation begins to occur
at higher lattice temperature. The effects of thermionic emission of hot
carriers and the presence of a non-equilibrium carrier distribution are also
shown to be distinct from simple lattice heating. This results in large
unsaturated photocurrents at high powers as the Fermi distribution exceeds that
of the heterointerface controlling carrier transport and rectification
Tri-partite complex for axonal transport drug delivery achieves pharmacological effect.
BACKGROUND: Targeted delivery of pharmaceutical agents into selected populations of CNS (Central Nervous System) neurons is an extremely compelling goal. Currently, systemic methods are generally used for delivery of pain medications, anti-virals for treatment of dermatomal infections, anti-spasmodics, and neuroprotectants. Systemic side effects or undesirable effects on parts of the CNS that are not involved in the pathology limit efficacy and limit clinical utility for many classes of pharmaceuticals. Axonal transport from the periphery offers a possible selective route, but there has been little progress towards design of agents that can accomplish targeted delivery via this intraneural route. To achieve this goal, we developed a tripartite molecular construction concept involving an axonal transport facilitator molecule, a polymer linker, and a large number of drug molecules conjugated to the linker, then sought to evaluate its neurobiology and pharmacological behavior. RESULTS: We developed chemical synthesis methodologies for assembling these tripartite complexes using a variety of axonal transport facilitators including nerve growth factor, wheat germ agglutinin, and synthetic facilitators derived from phage display work. Loading of up to 100 drug molecules per complex was achieved. Conjugation methods were used that allowed the drugs to be released in active form inside the cell body after transport. Intramuscular and intradermal injection proved effective for introducing pharmacologically effective doses into selected populations of CNS neurons. Pharmacological efficacy with gabapentin in a paw withdrawal latency model revealed a ten fold increase in half life and a 300 fold decrease in necessary dose relative to systemic administration for gabapentin when the drug was delivered by axonal transport using the tripartite vehicle. CONCLUSION: Specific targeting of selected subpopulations of CNS neurons for drug delivery by axonal transport holds great promise. The data shown here provide a basic framework for the intraneural pharmacology of this tripartite complex. The pharmacologically efficacious drug delivery demonstrated here verify the fundamental feasibility of using axonal transport for targeted drug delivery.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
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