The HIV-1 long terminal repeat contains an unusual element that induces the synthesis of short RNAs from various mRNA and snRNA promoters

We describe an unusual element that activates the synthesis of short transcripts from a wide variety of mRNA and small nuclear RNA (snRNA) promoters, including the U6 RNA polymerase III promoter. This inducer of short transcripts (IST) is located between positions -5 and +82 relative to the cap site in the HIV-1 LTR. In the presence of IST, the total transcriptional activity of the different promoters is greatly increased, but the resulting additional RNA molecules are short, ending around position +60. IST is not the RNA target (TAR) for Tat trans-activation; however, because it relies entirely on cellular factors for activity, IST may serve to provide abundant RNA targets for Tat trans-activation without a requirement for full-length viral mRNA expression

Geometry of escort distributions

Given an original distribution, its statistical and probabilistic attributs may be scanned by the associated escort distribution introduced by Beck and Schlogl and employed in the formulation of nonextensive statistical mechanics. Here, the geometric structure of the one-parameter family of the escort distributions is studied based on the Kullback-Leibler divergence and the relevant Fisher metric. It is shown that the Fisher metric is given in terms of the generalized bit-variance, which measures fluctuations of the crowding index of a multifractal. The Cramer-Rao inequality leads to the fundamental limit for precision of statistical estimate of the order of the escort distribution. It is also quantitatively discussed how inappropriate it is to use the original distribution instead of the escort distribution for calculating the expectation values of physical quantities in nonextensive statistical mechanics.Comment: 12 pages, no figure

Quantum heat engines and nonequilibrium temperature

A pair of two-level systems initially prepared in different thermal states and coupled to an external reversible work source, do not in general reach a common temperature at the end of a unitary work extraction process. We define an effective temperature for the final nonequilibrium but passive state of the bipartite quantum system and analyse its properties.Comment: Five pages, Accepted for publication in Physical Review

Generalized symmetric nonextensive thermostatistics and q-modified structures

We formulate a convenient generalization of the q-expectation value, based on the analogy of the symmetric quantum groups and q-calculus, and show that the q->q^{-1} symmetric nonextensive entropy preserves all of the mathematical structure of thermodynamics just as in the case of non-symmetric Tsallis statistics. Basic properties and analogies with quantum groups are discussed.Comment: 9 pages, 1 figure. To appear in Mod. Phys. Lett.

Work extremum principle: Structure and function of quantum heat engines

We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures $T_h > T_c$. The purpose of the engine is to extract work due to the temperature difference. Its dynamics is not restricted to the near equilibrium regime. The engine structure is determined by maximizing the extracted work under various constraints. When this maximization is carried out at finite power, the engine dynamics is described by well-defined temperatures and satisfies the local version of the second law. In addition, its efficiency is bounded from below by the Curzon-Ahlborn value $1-\sqrt{T_c/T_h}$ and from above by the Carnot value $1-(T_c/T_h)$. The latter is reached|at finite power|for a macroscopic engine, while the former is achieved in the equilibrium limit $T_h\to T_c$. When the work is maximized at a zero power, even a small (few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure

Nonextensive Entropies derived from Form Invariance of Pseudoadditivity

The form invariance of pseudoadditivity is shown to determine the structure of nonextensive entropies. Nonextensive entropy is defined as the appropriate expectation value of nonextensive information content, similar to the definition of Shannon entropy. Information content in a nonextensive system is obtained uniquely from generalized axioms by replacing the usual additivity with pseudoadditivity. The satisfaction of the form invariance of the pseudoadditivity of nonextensive entropy and its information content is found to require the normalization of nonextensive entropies. The proposed principle requires the same normalization as that derived in [A.K. Rajagopal and S. Abe, Phys. Rev. Lett. {\bf 83}, 1711 (1999)], but is simpler and establishes a basis for the systematic definition of various entropies in nonextensive systems.Comment: 16 pages, accepted for publication in Physical Review

A structured collaborative approach to intervention design using a modified intervention mapping approach: a case study using the Management and Interventions for Asthma (MIA) project for South Asian children

Background: To describe how using a combined approach of community-based participatory research and intervention mapping principles could inform the development of a tailored complex intervention to improve management of asthma for South Asian (SA) children; Management and Interventions for Asthma (MIA) study. / Methods: A qualitative study using interviews, focus groups, workshops, and modified intervention mapping procedures to develop an intervention planning framework in an urban community setting in Leicester, UK. The modified form of intervention mapping (IM) included: systematic evidence synthesis; community study; families and healthcare professionals study; and development of potential collaborative intervention strategies. Participants in the community study were 63 SA community members and 12 key informants; in-depth semi-structured interviews involved 30 SA families, 14 White British (WB) families and 37 Healthcare Professionals (HCPs) treating SA children living with asthma; prioritisation workshops involved 145 SA, 6 WB and 37 HCP participants; 30 participants in finalisation workshops. / Results: Two key principles were utilised throughout the development of the intervention; community-based participatory research (CBPR) principles and intervention mapping (IM) procedures. The CBPR approach allowed close engagement with stakeholders and generated valuable knowledge to inform intervention development. It accounted for diverse perceptions and experiences with regard to asthma and recognised the priorities of patients and their families/caregivers for service improvement. The ‘ACT on Asthma’ programme was devised, comprising four arms of an intervention strategy: education and training, clinical support, advice centre and raising awareness, to be co-ordinated by a central team. / Conclusions: The modified IM principles utilised in this study were systematic and informed by theory. The combined IM and participatory approach could be considered when tailoring interventions for other clinical problems within diverse communities. The IM approach to intervention development was however resource intensive. Working in meaningful collaboration with minority communities requires specific resources and a culturally competent methodology

Extended gaussian ensemble solution and tricritical points of a system with long-range interactions

The gaussian ensemble and its extended version theoretically play the important role of interpolating ensembles between the microcanonical and the canonical ensembles. Here, the thermodynamic properties yielded by the extended gaussian ensemble (EGE) for the Blume-Capel (BC) model with infinite-range interactions are analyzed. This model presents different predictions for the first-order phase transition line according to the microcanonical and canonical ensembles. From the EGE approach, we explicitly work out the analytical microcanonical solution. Moreover, the general EGE solution allows one to illustrate in details how the stable microcanonical states are continuously recovered as the gaussian parameter $\gamma$ is increased. We found out that it is not necessary to take the theoretically expected limit $\gamma \to \infty$ to recover the microcanonical states in the region between the canonical and microcanonical tricritical points of the phase diagram. By analyzing the entropy as a function of the magnetization we realize the existence of unaccessible magnetic states as the energy is lowered, leading to a treaking of ergodicity.Comment: 8 pages, 5 eps figures. Title modified, sections rewritten, tricritical point calculations added. To appear in EPJ

Implications of Form Invariance to the Structure of Nonextensive Entropies

The form invariance of the statement of the maximum entropy principle and the metric structure in quantum density matrix theory, when generalized to nonextensive situations, is shown here to determine the structure of the nonextensive entropies. This limits the range of the nonextensivity parameter to so as to preserve the concavity of the entropies. The Tsallis entropy is thereby found to be appropriately renormalized.Comment: 8 page