High resolution forecast models of water vapour over mountains: comparison of results from the UM and MERIS

Propagation delay due to variable tropospheric water vapor (WV) is one of the most intractable problems for radar interferometry, particularly over mountains. The WV field can be simulated by an atmospheric model, and the difference between the two fields is used to correct the radar interferogram. Here, we report our use of the U.K. Met Office Unified Model in a nested mode to produce high-resolution forecast fields for the 3-km-high Mount Etna volcano. The simulated precipitablewater field is validated against that retrieved from the Medium Resolution Imaging Spectrometer (MERIS) radiometer on the Envisat satellite, which has a resolution of 300 m. Two case studies, one from winter (November 24, 2004) and one from summer (June 25, 2005), show that the mismatch between the model and the MERIS fields (rms = 1.1 and 1.6 mm, respectively) is small. One of the main potential sources of error in the models is the timing of the WV field simulation. We show that long-wavelength upper tropospheric troughs of low WV could be identified in both the model output and Meteosat WV imagery for the November 24, 2004 case and used to choose the best time of model output. © 2007 IEEE

Characterising a solid state qubit via environmental noise

We propose a method for characterising the energy level structure of a solid-state qubit by monitoring the noise level in its environment. We consider a model persistent-current qubit in a lossy resevoir and demonstrate that the noise in a classical bias field is a sensitive function of the applied field.Comment: 3 Figure

Quasiparticle lifetime behaviour in a simplified self-consistent T-matrix treatment of the attractive Hubbard model in 2D

The attractive Hubbard model on a 2-D square lattice is studied at low electronic densities using the ladder approximation for the pair susceptibility. This model includes (i) the short coherence lengths known to exist experimentally in the cuprate superconductors, and (ii) two-particle bound states that correspond to electron pairs. We study the quasiparticle lifetimes in both non self-consistent and self-consistent theories, the latter including interactions between the pairs. We find that if we include the interactions between pairs the quasiparticle lifetimes vary approximately linearly with the inverse temperature, consistent with experiment.Comment: 2 pages, including 2 figures, to appear in the proceedings of the ICNS '9

A fatal case of louping-ill in a dog: immunolocalization and full genome sequencing of the virus

Louping-ill (LI), caused by louping-ill virus (LIV), results in a frequently fatal encephalitis primarily affecting sheep and red grouse (Lagopus lagopus scotica), but it does occur in other species. An adult male Border collie dog was definitively diagnosed with fatal LI and the lesion profile, LIV antigen distribution and full genome sequence of the LIV responsible were investigated to determine if this differed significantly from sheep-derived LIV. No gross lesions were present. The histological lesions were confined to the central nervous system and comprised of lymphocytic perivascular cuffs, glial foci, neuronal necrosis and neuronophagia. Immunolocalization of viral antigen showed small amounts present in neurons only. These histological and immunohistochemical findings were similar to those reported in affected sheep. Compared with published full genome sequences of sheep-derived LIV, only very minor differences were present and phylogenetically the virus clustered individually between a subclade containing Scottish strains, LIV 369/T2 and G and another subclade containing an English isolate LIV A. The LIV isolated from the dog shares a common progenitor with LIV A. These findings suggest there is no canine-specific LIV strain, dogs are susceptible to sheep-associated strains of LI and with the increase in tick prevalence, and therefore exposure to LIV, a safe, effective vaccine for dogs may be required

Development of Luminescence Tests to Identify Irradiated Foods. Project N1701

<p>This is the final report of project N170l, commissioned by MAFF from October 1990 until March 1992. The principle aims of the project, at a time when statutory changes involving strict labelling rules were anticipated, were to consolidate the thermoluminescence technique already developed at SURRC and to investigate it's extension to fruits and vegetables.</p> <p>The TL procedures for mineral separation were further developed by the incorporation of pre-concentration steps. These steps were introduced in order to improve the the sensitivity of the TL signal, particularly, where the separation technique resulted in low mineral yield for commercially clean samples. This has resulted in an order of magnitude increase in the absolute, TL, signal levels and provides a means of obtaining larger quantities of minerals for any further quantification, thus reducing the ambiguity of interpretation of data.</p> <p>An EC interlaboratory trial was instigated, using the full mineral separation method with reirradiation on a set of calibrated reference materials and paired (irradiated and unirradiated) samples of 12 commercial grade herbs and spices. Despite the diversity of experience and equipment employed, results from all laboratories showed that it was possible to determine which samples were irradiated. This demonstrated the strength of the separation method that its implementation could be successfully achieved in other laboratories. The procedure was then formally recognised and published, by MAFF, for detection of irradiated food for enforcement of UK legislation.</p> <p>As the mineral debris responsible for TL in herbs and spices occurs ubiquitously on all foodstuffs, which have been exposed to wind and soil, investigating the application of TL to fruits and vegetables was a natural extension of the previous work. An extensive survey was conducted of TL signals from fruits and vegetables, including exotic varieties. Minerals were separated from duplicated pairs of irradiated and unirradiated samples of 22 fruits and 20 vegetables. TL results demonstrated unambiguous discrimination between irradiated and unirradiated vegetables provided that concordance diagrams were used. For soft fruits in particular water based separation produced more variable results. However, subsequent analyses using a full density separation with HCI wash were more successful. It was recognised that whereas herbs and spices are largely protected from exposure to light during production and distribution, this is unlikely to be the case for fruits and vegtables. Since light exposure is known to reduce TL signal intensity, a set of illumination experiments was conducted to investigate the implications of optical bleaching for identification. Light boxes were constructed and characterised to simulated optical bleaching under controlled conditions. Two series of experiments were conducted with irradiated and control mangos. In the first experiment the effects of exposure to two different light sources at a level of 1 J cm-2 were investigated using 40 mangos. In the second experiment the influence of duration of exposure from 1 - 128 J cm-2 was examined for artificial daylight illumination of a further 96 mangos. The results of these studies show that although the TL signal is reduced as a result of exposure to daylight, there exists a residual unbleachable component comprising upto 40-50% of the original signal. In most cases the resulting TL will be distinguishable from background levels.</p> <p>As a result of this work it is now possible to extend TL detection protocols to a wide range of fruits and vegetables. Providing that recontamination with unirradiated minerals has not occurred after irradiation, the majority of treated fruits and vegetables are expected to be detectable. Positive signals will imply an irradiation treatment. There remains some possibility of false negative results from a small proportion of irradiated products.</p&gt

An extension of the coupled-cluster method: A variational formalism

A general quantum many-body theory in configuration space is developed by extending the traditional coupled cluter method (CCM) to a variational formalism. Two independent sets of distribution functions are introduced to evaluate the Hamiltonian expectation. An algebraic technique for calculating these distribution functions via two self-consistent sets of equations is given. By comparing with the traditional CCM and with Arponen's extension, it is shown that the former is equivalent to a linear approximation to one set of distribution functions and the later is equivalent to a random-phase approximation to it. In additional to these two approximations, other higher-order approximation schemes within the new formalism are also discussed. As a demonstration, we apply this technique to a quantum antiferromagnetic spin model.Comment: 15 pages. Submitted to Phys. Rev.

Akimiski Island, Nunavut, Canada: The Use of Cree Oral History and Sea-Level Retrodiction to Resolve Aboriginal Title

On 1 April 1999, Akimiski Island of the western James Bay region of northern Ontario, Canada, was included in the newly formed territory of Nunavut, Canada—an Inuit-dominated territory—even though the Inuit had never asserted Aboriginal title to the island. By contrast, the Omushkegowuk Cree of the western James Bay region have asserted Aboriginal title to Akimiski Island. The Government of Canada by their action (or inaction) has reversed the onus of responsibility for proof of Aboriginal title from the Inuit to the Cree. In other words, the Government of Canada did not follow their own guidelines and the common-law test for proof of Aboriginal title. In this paper, we documented and employed Cree oral history as well as a sea-level retrodiction (based on state-of-the-art numerical modeling of past sea-level changes in James Bay), which incorporated a modified ICE-6G ice history and a 3-D model of Earth structure, to establish that criterion 2 of the test for Aboriginal title has now been fully met. In other words, Cree traditional use and occupancy of Akimiski Island was considered sufficiently factual at the time of assertion of sovereignty by European nations. As all the criteria of the common-law test for proof of Aboriginal title in Canada, with respect to Akimiski Island, have now been addressed, the Cree have sufficient basis to initiate the process of a formal land claim.Le 1er avril 1999, l’île Akimiski, située dans la région ouest de la baie James, dans le nord de l’Ontario, au Canada, a été intégrée au nouveau territoire du Nunavut, territoire dominé par les Inuits, même si ceux-ci n’avaient jamais revendiqué le titre ancestral de cette île. En revanche, les Cris omushkegowuk de la région ouest de la baie James ont revendiqué leur titre ancestral à l’égard de l’île Akimiski. Le geste (ou l’absence de geste) du gouvernement du Canada a eu pour effet d’inverser la responsabilité de prouver le titre ancestral des Inuits aux Cris. Autrement dit, le gouvernement du Canada n’a pas respecté ses propres directives et les critères de droit commun comme preuve de titre ancestral. Dans cet article, nous avons documenté et employé l’histoire orale crie ainsi qu’une rétrodiction du niveau de la mer (d’après une modélisation numérique perfectionnée d’anciens changements du niveau de la mer de la baie James), contenant un historique modifié de la glace ICE-6G et une modélisation en trois dimensions de la structure de la Terre, afin d’établir que le critère 2 des critères du titre ancestral est maintenant entièrement atteint. Autrement dit, l’usage et l’occupation traditionnels de l’île Akimiski par les Cris ont été considérés comme des faits suffisants au moment de la revendication de la souveraineté par les nations européennes. Puisque tous les critères de droit commun permettant de prouver le titre ancestral de l’île Akimiski au Canada ont maintenant été respectés, les Cris disposent de fondements suffisants pour entreprendre une revendication territoriale officielle

Characterising a solid state qubit via environmental noise

We propose a method for characterising the energy level structure of a solid state qubit by monitoring the noise level in its environment. We consider a model persistent current qubit in a lossy reservoir and demonstrate that the noise in a classical bias field is a sensitive function of the applied field

Noninvasive imaging of signals in digital circuits

In this article we describe the construction and use of a noninvasive (noncontact) electric potential probe to measure time delays of signals propagating through digital circuits. As we show, by incorporating such probes into a scanning microscope system we have been able to create time delay images of these signals.We suggest that future developments of this technique may lead to real time, high resolution imaging of digital pulses across complex very large scale integrated circuits

Tick holocyclotoxins trigger host paralysis by presynaptic inhibition

Ticks are important vectors of pathogens and secreted neurotoxins with approximately 69 out of 692 tick species having the ability to induce severe toxicoses in their hosts. The Australian paralysis tick (Ixodes holocyclus) is known to be one of the most virulent tick species producing a flaccid paralysis and fatalities caused by a family of neurotoxins known as holocyclotoxins (HTs). The paralysis mechanism of these toxins is temperature dependent and is thought to involve inhibition of acetylcholine levels at the neuromuscular junction. However, the target and mechanism of this inhibition remain uncharacterised. Here, we report that three members of the holocyclotoxin family; HT-1 (GenBank AY766147), HT-3 (GenBank KP096303) and HT-12 (GenBank KP963967) induce muscle paralysis by inhibiting the dependence of transmitter release on extracellular calcium. Previous study was conducted using extracts from tick salivary glands, while the present study is the first to use pure toxins from I. holocyclus. Our findings provide greater insight into the mechanisms by which these toxins act to induce paralysis