Efficiency of a Brownian information machine

A Brownian information machine extracts work from a heat bath through a feedback process that exploits the information acquired in a measurement. For the paradigmatic case of a particle trapped in a harmonic potential, we determine how power and efficiency for two variants of such a machine operating cyclically depend on the cycle time and the precision of the positional measurements. Controlling only the center of the trap leads to a machine that has zero efficiency at maximum power whereas additional optimal control of the stiffness of the trap leads to an efficiency bounded between 1/2, which holds for maximum power, and 1 reached even for finite cycle time in the limit of perfect measurements.Comment: 9 pages, 2 figure

A New ABCA3 Gene Mutation Presenting as Early Neonatal Surfactant Deficiency

Mutations of the ATP-binding cassette transporter A3 gene (ABCA3) causing the dysfunction of surfactant proteins are a well-established cause of interstitial lung disease. The clinical presentation is variable ranging from neonatal early death to mild forms of interstitial lung disease in the adult. We present the case of a newborn with early neonatal respiratory distress. The clinical and radiologic findings were compatible with interstitial lung disease. The disease progressed toward severe respiratory insufficiency and the patient died at the age of 3 years. A variant not yet described in the literature was found in the ABCA3 gene (c.4442C>T), in apparent homozygosity. Parental genetic studies revealed that only the father was a carrier for this variant. The quantitative study of the ABCA3 gene in our patient revealed a deletion affecting exon 32 and possibly 29. This report describes the phenotype of a new ABCA3 variant causing surfactant deficiency while also highlighting the importance of considering gene deletions in case of unconfirmed homozygosity.info:eu-repo/semantics/publishedVersio

J/Psi suppression in colliding nuclei: statistical model analysis

We consider the $J/\Psi$ suppression at a high energy heavy ion collision. An ideal gas of massive hadrons in thermal and chemical equilibrium is formed in the central region. The finite-size gas expands longitudinally in accordance with Bjorken law. The transverse expansion in a form of the rarefaction wave is taken into account. We show that $J/\Psi$ suppression in such an environment, when combined with the disintegration in nuclear matter, gives correct evaluation of NA38 and NA50 data in a broad range of initial energy densities.Comment: 14 pages, 13 figures. Accepted for publication in Phys. Rev.

Weakly correlated electrons on a square lattice: a renormalization group theory

We study the weakly interacting Hubbard model on the square lattice using a one-loop renormalization group approach. The transition temperature T_c between the metallic and (nearly) ordered states is found. In the parquet regime, (T_c >> |mu|), the dominant correlations at temperatures below T_c are antiferromagnetic while in the BCS regime (T_c << |mu|) at T_c the d-wave singlet pairing susceptibility is most divergent.Comment: 12 pages, REVTEX, 3 figures included, submitted to Phys. Rev. Let

Hamiltonian Derivations of the Generalized Jarzynski Equalities under Feedback Control

In the presence of feedback control by "Maxwell's demon," the second law of thermodynamics and the nonequilibrium equalities such as the Jarzynski equality need to be generalized. In this paper, we derive the generalized Jarzynski equalities for classical Hamiltonian dynamics based on the Liouville's theorem, which is the same approach as the original proof of the Jarzynski equality [Phys. Rev. Lett. 78, 2690 (1997)]. The obtained equalities lead to the generalizations of the second law of thermodynamics for the Hamiltonian systems in the presence of feedback control.Comment: Proceedings of "STATPHYS - Kolkata VII", November 26-30, 2010, Kolkata, Indi

Charmonium suppression in p-A collisions

The new high precision data on charmonium production in proton-nucleus collisions by the E866/NuSea collaboration at Fermilab allow - together with older data at lower energies - to fix a unique set of parameters for the standard production and absorption scenario of charmonium in a proton-nucleus reaction. In this scenario the c-cbar pair is formed in an octet state, emits a gluon and continues its radial expansion in a singlet state until it has reached the charmonium radius. In all three phases it can interact with the nuclear environment. We find that the lifetime of the octet state is much shorter than acceptable on physical grounds. This challenges the physical reality of the first phase in the standard scenario.Comment: 8 pages, 10 figure

New possibilities for the gauging of chiral bosons

We study a new mechanism for the electromagnetic gauging of chiral bosons showing that new possibilities emerge for the interacting theory of chiral scalars. We introduce a chirally coupled gauge field necessary to mod out the degree of freedom that obstructs gauge invariance in a system of two opposite chiral bosons soldering them together.Comment: 11 pages, Latex. Accepted for publication in Physical Review

Teaching writing in primary education (grades 1–6) in Australia: A national survey

Providing adequate writing instruction and practice in schools is an essential cornerstone of writing development and it affords a diagnostic approach for teachers. But what writing instruction is being practiced in Australian primary schools? The aim of this study was to survey a sample of teachers (n = 310) about their instructional practices for writing and their preparation and self-efficacy to teach writing. The majority of the teachers surveyed indicated they allocated on average less than three hours per week for writing practice in their classrooms, with findings further showing a large variability in the frequency of writing practice ranging from 15 min to 7.5 h per week. Findings suggested an emphasis placed on teaching foundational skills, such as spelling, over the teaching of process skills, such as planning and revising. Results further indicated that less emphasis is placed on teaching handwriting and typing. The majority of participating teachers reported implementing only six of the 20 different instructional practices included in the survey on a weekly basis, with school-home strategies being the least frequently reported strategies to foster students’ writing development. Most teachers expressed positive beliefs about their preparation and self-efficacy for teaching writing. Results from multiple regression analysis showed that preparation and self-efficacy for teaching writing significantly and statistically accounted for variability in using evidence-based practices, teaching foundational skills, and teaching process skills. However, only self-efficacy made a statically significant contribution to predicting strategies to extend writing to the home environment. Implications for teaching and recommendations for research are provided