Cytolethal distending toxin (CDT)-negative Campylobacter jejuni strains and anti-CDT neutralising antibodies induced during human infection but not chicken colonisation

The cytolethal distending toxin (CDT) of Campylobacter jejuni was detectable, using an in vitro assay, in most but not all of 24 strains tested. The reason for the absence of toxin activity in these naturally occurring CDT-negative C. jejuni strains was then investigated at the genetic level. CDT is encoded by three highly conserved genes, cdtA, -B, and -C. In the CDT-negative strains, two types of mutation were identified. The CDT activities of C. jejuni strains possessing both types of mutation were successfully complemented with the functional genes of C. jejuni 11168. The first type of mutation comprised a 667-bp deletion across cdtA and cdtB and considerable degeneration in the remainder of the cdt locus. Using a PCR technique to screen for this deletion, this mutation occurred in fewer than 3% of 147 human, veterinary, and environmental strains tested. The second type of mutation involved at least four nonsynonymous nucleotide changes, but only the replacement of proline with serine at CdtB position 95 was considered important for CDT activity. This was confirmed by site-directed mutagenesis. This type of mutation also occurred in fewer than 3% of strains as determined using a LightCycler biprobe assay. The detection of two CDT-negative clinical isolates raised questions about the role of CDT in some cases of human campylobacteriosis. To determine if anti-CDT antibodies are produced in human infection, a toxin neutralization assay was developed and validated using rabbit antisera. Pooled human sera from infected patients neutralized the toxin, indicating expression and immunogenicity during infection. However, no neutralizing antibodies were detected in colonized chickens despite the expression of CDT in the avian gut as indicated by reverse transcription-PCR

Experimental evidence on promotion of electric and improved biomass cookstoves.

Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion

Advanced photonic routing sub-systems with efficient routing control

In recent years, there has been much interest in the development of optical switches which can route optical signals from different input guides to different outputs based on thermo-optic and electro-optic technologies. Such switches, which can be reconfigured on millisecond and microsecond timescales, have already attracted commercial interest. However switches which are able to reconfigure on the nanosecond timescales required for packet switching have been more challenging and only in recent years, have router concepts been devised to allow lossless routers to be constructed able to switch on nanosecond timescales with more than 16×16 ports. This paper will therefore review the advances that have occurred to allow such operation and then describe recent studies that have begun to determine the electronic control and functionality required to enable full and practical operation of such switches in high performance networks.This research has received funding from the UK Engineering and Physical Sciences Research Council through the INTERNET Project, STAR and COPOS II grants and the European Commission under FP7 grant agreement ICT 257210 PARADIGM.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ICTON.2015.719339

Towards an Efficient Finite Element Method for the Integral Fractional Laplacian on Polygonal Domains

We explore the connection between fractional order partial differential equations in two or more spatial dimensions with boundary integral operators to develop techniques that enable one to efficiently tackle the integral fractional Laplacian. In particular, we develop techniques for the treatment of the dense stiffness matrix including the computation of the entries, the efficient assembly and storage of a sparse approximation and the efficient solution of the resulting equations. The main idea consists of generalising proven techniques for the treatment of boundary integral equations to general fractional orders. Importantly, the approximation does not make any strong assumptions on the shape of the underlying domain and does not rely on any special structure of the matrix that could be exploited by fast transforms. We demonstrate the flexibility and performance of this approach in a couple of two-dimensional numerical examples

Power margin reduction in linear passive UHF RFID tag arrays

This paper studies the power margin reduction in linear passive UHF RFID tag arrays due to proximity effects. It is shown experimentally that a 40% reduction in tag power margin occurs when two tags are placed with a separation of less than 2cm. Major causes of tag sensitivity degradation due to proximity in arrays are analyzed by experiment and simulation, including tag detuning, shadowing and re-emission cancellation. It is shown that tag detuning has a significant effect when tags are separated by less than 7mm. At larger separations in excess of 1cm, the tag shadowing effect and interactions between the backscattered waves cause more significant degradation for large tag arrays.This work has been supported by UK Engineering and Physical Science Research Council via the COPOSII project.This is the author accepted manuscript. The final version is available at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=6934248

Flexible structure control laboratory development and technology demonstration

An experimental structure is described which was constructed to demonstrate and validate recent emerging technologies in the active control and identification of large flexible space structures. The configuration consists of a large, 20 foot diameter antenna-like flexible structure in the horizontal plane with a gimballed central hub, a flexible feed-boom assembly hanging from the hub, and 12 flexible ribs radiating outward. Fourteen electrodynamic force actuators mounted to the hub and to the individual ribs provide the means to excite the structure and exert control forces. Thirty permanently mounted sensors, including optical encoders and analog induction devices provide measurements of structural response at widely distributed points. An experimental remote optical sensor provides sixteen additional sensing channels. A computer samples the sensors, computes the control updates and sends commands to the actuators in real time, while simultaneously displaying selected outputs on a graphics terminal and saving them in memory. Several control experiments were conducted thus far and are documented. These include implementation of distributed parameter system control, model reference adaptive control, and static shape control. These experiments have demonstrated the successful implementation of state-of-the-art control approaches using actual hardware

Bekenstein entropy bound for weakly-coupled field theories on a 3-sphere

We calculate the high temperature partition functions for SU(Nc) or U(Nc) gauge theories in the deconfined phase on S^1 x S^3, with scalars, vectors, and/or fermions in an arbitrary representation, at zero 't Hooft coupling and large Nc, using analytical methods. We compare these with numerical results which are also valid in the low temperature limit and show that the Bekenstein entropy bound resulting from the partition functions for theories with any amount of massless scalar, fermionic, and/or vector matter is always satisfied when the zero-point contribution is included, while the theory is sufficiently far from a phase transition. We further consider the effect of adding massive scalar or fermionic matter and show that the Bekenstein bound is satisfied when the Casimir energy is regularized under the constraint that it vanishes in the large mass limit. These calculations can be generalized straightforwardly for the case of a different number of spatial dimensions.Comment: 32 pages, 12 figures. v2: Clarifications added. JHEP versio

Smolyak's algorithm: A powerful black box for the acceleration of scientific computations

We provide a general discussion of Smolyak's algorithm for the acceleration of scientific computations. The algorithm first appeared in Smolyak's work on multidimensional integration and interpolation. Since then, it has been generalized in multiple directions and has been associated with the keywords: sparse grids, hyperbolic cross approximation, combination technique, and multilevel methods. Variants of Smolyak's algorithm have been employed in the computation of high-dimensional integrals in finance, chemistry, and physics, in the numerical solution of partial and stochastic differential equations, and in uncertainty quantification. Motivated by this broad and ever-increasing range of applications, we describe a general framework that summarizes fundamental results and assumptions in a concise application-independent manner

Electrochemical polymerisation of phenol in aqueous solution on a Ta/PbO2 anode

This paper deals with the treatment of aqueous phenol solutions using an electrochemical technique. Phenol can be partly eliminated from aqueous solution by electrochemically initiated polymerisation. Galvanostatic electrolyses of phenol solutions at concentration up to 0.1 mol dm−3 were carried out on a Ta/PbO2 anode. The polymers formed are insoluble in acidic medium but soluble in alkaline. These polymers were filtered and then dissolved in aqueous solution of sodium hydroxide (1 mol dm−3). The polymers formed were quantified by total organic carbon (TOC) measurement. It was found that the conversion of phenol into polymers increases as a function of initial concentration, anodic current density, temperature, and solution pH. The percentage of phenol polymerised can reach 15%