Large Gravitational Wave Background Signals in Electroweak Baryogenesis Scenarios

The bubble wall velocity in an electroweak first order phase transition is a key quantity both for electroweak baryogenesis and for the production of a stochastic background of gravitational waves that may be probed in the future through gravitational wave experiments like LISA or BBO. We show that, contrary to the conclusion drawn from previous studies, it is actually possible to generate a potentially large gravitational wave signal while satisfying the requirements for viable electroweak baryogenesis, once the effects of the hydrodynamics of bubble growth are taken into account. Then, the observation of a large gravitational wave background from the electroweak phase transition would not necessarily rule out electroweak baryogenesis as the mechanism having generated the observed baryon asymmetry of the universe.Comment: 6 pages. References added. Accepted for publication in Phys. Rev.

Merchant Transmission Investment

We examine the performance attributes of a merchant transmission investment framework that relies on �market driven� transmission investment to provide the infrastructure to support competitive wholesale markets for electricity. Under a stringent set of assumptions, the merchant investment model appears to solve the natural monopoly problem and the associated need for regulating transmission companies traditionally associated with electric transmission networks. We expand the model to incorporate imperfection in wholesale electricity markets, lumpiness in transmission investment opportunities, stochastic attributes of transmission networks and associated property rights definition issues, the effects of the behaviour system operators and transmission owners on transmission capacity and reliability, co-ordination and bargaining considerations, forward contract, commitment and asset specificity issues. This significantly undermines the attractive properties of the merchant investment model. Relying primarily on a market driven investment framework to govern investment is likely to lead to inefficient investment decisions and undermine the performance of competitive markets

Nonunitary projective transcorrelation theory inspired by the F12 ansatz

An alternative nonunitary transcorrelation, inspired by the F12 ansatz, is investigated. In contrast to the Jastrow transcorrelation of Boys-Handy, the effective Hamiltonian of this projective transcorrelation features: 1. a series terminating formally at four-body interactions. 2. no spin-contamination within the non-relativistic framework. 3. simultaneous satisfaction of the singlet and triplet first-order cusp conditions. 4. arbitrary choices of pairs for correlation including frozen core approximations. We discuss the connection between the projective transcorrelation and F12 theory with applications to small molecules, to show that the cusp conditions play an important role to reduce the uncertainty arising from the nonunitary transformation

Detection of avian influenza antibodies and antigens in poultry and some wild birds in Kogi state, Nigeria

The global spread of HPAI (H5N1) between 2005 and 2006 was blamed on movement of migratory wild birds and trade in live poultry across continents from infected regions. A survey was carried out to detect the presence of avian influenza (AI) antibodies in wild birds and AI viruses in poultry and wild birds from Kogi state, Nigeria. Haemagglutination inhibition (HI) test and enzyme link immunosorbent assay (ELISA) were used to detect AI antibodies in some species of apparently healthy wild birds during the survey. Using HI test, the wild birds were negative for AI (H5) antibodies but ELISA detected AI (NP) antibodies in Black Stork (Ciconia nigra) with an overall seroprevalence of 4.5% and mean titre of 24.50±2.400 EU. Cloacal swabs from the same species of wild birds that were tested for antibodies and 710 oropharyngeal swabs from poultry were tested for AI viruses using RT-PCR with primers targeting the AI matrix proteins but were negative for AI viruses. The detection of AI (NP) antibodies in wild birds but failure to detect the viruses showed that the exposure might not be recent. We recommend that poultry should be prevented from contact with wild water birds and a broad based surveillance for AI viruses in poultry and wild birds should be carried out in Kogi state, Nigeria.Keywords: Avian influenza, Black stork, ELISA, HI, RT-PC

Flight Tests, Performances and Flight Certification of a Twin-Engine Light Aircraft

This paper deals with flight test activities performed on P2006T, a twin-engine light aircraft recently designed and produced by Tecnam. Research activities and flight tests have been conducted during the flight certification of P2006T for the normal category under CS-23. All the acquired data and flight results presented have been focused on both aircraft certification and on aircraft performances, stability and flight qualities measurement. The data have been acquired through a light, accurate and reliable flight instrumentation available at DIAS (Department of Aerospace Engineering). Some flight data about aircraft leveled speed, stall speed, climb characteristics and ground performances (take-off and landing) will be presented. After preliminary flight tests, winglets have been designed and added to the final configuration in order to obtain good climb performances also in OEI (One Engine Inoperative) conditions. Accurate stall tests have been performed in all configurations and influence of both entry-rate and load factor on stall speed have been highlighted. Excellent ground performances have been measured with short take-off and landing distances compared with similar airplanes. All measured flight performances can be considered very good for this aircraft category and have been used to demonstrate aircraft safety and to obtain CS23 certification

Patients' views on improving sickle cell disease management in primary care: focus group discussion.

OBJECTIVES: To assess sickle cell disease (SCD) patient and carer perspectives on the primary care services related to SCD that they receive from their general practitioner (GP). DESIGN: A focus group discussion was used to elicit the views of patients about the quality of care they receive from their primary health-care providers and what they thought was the role of primary care in SCD management. The focus group discussion was video recorded. The recording was then examined by the project team and recurring themes were identified. A comparison was made with notes made by two scribes also present at the discussion. SETTING: Sickle Cell Society in Brent, UK. PARTICIPANTS: Ten participants with SCD or caring for someone with SCD from Northwest London, UK. MAIN OUTCOME MEASURES: Patients perceptions about the primary care services they received, and a list of key themes and suggestions. RESULTS: Patients and carers often bypassed GPs for acute problems but felt that GPs had an important role to play around repeat prescriptions and general health care. These service users believed SCD is often ignored and deemed unimportant by GPs. CONCLUSION: Participants wanted the health service to support primary health-care providers to improve their knowledge and understanding of SCD. Key themes and suggestions from this focus group have been used to help develop an educational intervention for general practice services that will be used to improve SCD management in primary care

Improved algorithms of quantum imaginary time evolution for ground and excited states of molecular systems

Quantum imaginary time evolution (QITE) is a recently proposed quantum-classical hybrid algorithm that is guaranteed to reach the lowest state of system. In this study, we present several improvements on QITE, mainly focusing on molecular applications. We analyze the derivation of the underlying QITE equation order-by-order, and suggest a modification that is theoretically well founded. Our results clearly indicate the soundness of the here-derived equation, enabling a better approximation of the imaginary time propagation by a unitary. We also discuss how to accurately estimate the norm of an imaginary-time-evolved state, and applied it to excited state calculations using the quantum Lanczos algorithm. Finally, we propose the folded-spectrum QITE scheme as a straightforward extension of QITE for general excited state simulations. The effectiveness of all these developments is illustrated by noiseless simulations, offering the further insights into quantum algorithms for imaginary time evolution.Comment: 10 pages, 5 figures, 1 tabl

Spin-projection for quantum computation: A low-depth approach to strong correlation

Although spin is a core property in fermionic systems, its symmetry can be easily violated in a variational simulation, especially when strong correlation plays a vital role therein. In this study, we will demonstrate that the broken spin-symmetry can be restored exactly in a quantum computer, with little overhead in circuits, while delivering additional strong correlation energy with the desired spin quantum number. The proposed scheme permits drastic reduction of a potentially large number of measurements required to ensure spin-symmetry by employing a superposition of only a few rotated quantum states. Our implementation is universal, simple, and, most importantly, straightforwardly applicable to any ansatz proposed to date.Comment: 9 pages, 7 figures, 2 table