Mode engineering with a one-dimensional superconducting metamaterial

We propose a way to control the Josephson energy of a single Josephson junction embedded in one- dimensional superconducting metamaterial: an inhomogeneous superconducting loop, made out of a superconducting nanowire or a chain of Josephson junctions. The Josephson energy is renormalized by the electromagnetic modes propagating along the loop. We study the behaviour of the modes as well as of their frequency spectrum when the capacitance and the inductance along the loop are spatially modulated. We show that, depending on the amplitude of the modulation, the renormalized Josephson energy is either larger or smaller than the one found for a homogeneous loop. Using typical experimental parameters for Josepshon junction chains and superconducting nanowires, we conclude that this mode-engineering can be achieved with currently available metamaterials

Universality and m_X cut effects in B -> Xs l+ l-

The most precise comparison between theory and experiment for the B -> Xs l+ l- rate is in the low q^2 region, but the hadronic uncertainties associated with an experimentally required cut on m_X potentially spoil the search for new physics in these decays. We show that a 10-30% reduction of d\Gamma(B -> Xs l+ l-) / dq^2 due to the m_X cut can be accurately computed using the B -> X_s gamma shape function. The effect is universal for all short distance contributions in the limit m_X^2 << m_B^2, and this universality is spoiled neither by realistic values of the m_X cut nor by alpha_s corrections. Both the differential decay rate and forward-backward asymmetry with an m_X cut are computed.Comment: 5 pages, journal versio

Extracting short distance information from b-->s[script-l]+[script-l]- effectively

We point out that in inclusive B-->Xs[script-l]+[script-l]- decay an angular decomposition provides a third (q2 dependent) observable sensitive to a different combination of Wilson coefficients than the rate and the forward-backward asymmetry. Since a precise measurement of q2 dependence requires large data sets, it is important to consider the data integrated over regions of q2. We develop a strategy to extract all measurable Wilson coefficients in B-->Xs[script-l]+[script-l]- from a few simple integrated rates in the low q2 region. A similar decomposition in B-->K*[script-l]+[script-l]-, together with the B-->K*gamma rate, also provides a determination of the Wilson coefficients, without reliance on form factor models and without having to measure the zero of the forward-backward asymmetry

Antifouling bastadin congeners target blue mussel phenoloxidase and complex copper(II) ions

Synthetically prepared congeners of spongederived bastadin derivatives such as 5,5&apos;-dibromohemibastadin- 1 (DBHB) that suppress the settling of barnacle larvae were identified in this study as strong inhibitors of blue mussel phenoloxidase that is involved in the firm attachment of mussels to a given substrate. The IC50 value of DBHB as the most active enzyme inhibitor encountered in this study amounts to 0.84 mu M. Inhibition of phenoloxidase by DBHB is likely due to complexation of copper(II) ions from the catalytic centre of the enzyme by the a-oxo-oxime moiety of the compound as shown here for the first time by structure activity studies and by X-ray structure determination of a copper(II) complex of DBHB.Biotechnology &amp; Applied MicrobiologyMarine &amp; Freshwater BiologySCI(E)EI0ARTICLE61148-11581

Gender inequality and sex differences in physical fighting, physical activity, and injury among adolescents across 36 countries

Purpose: Sex differences in adolescent health are widely documented, but social explanations for these sex differences are scarce. This study examines whether societal gender inequality (i.e., men’s and women’s unequal share in political participation, decision-making power, economic participation and command over resources) relates to sex differences in adolescent physical fighting, physical activity, and injuries. Methods: National-level data on gender inequality (i.e. the United Nations Development Program’s Gender Inequality Index) were linked to health data from 71,255 15-year olds from 36 countries in the 2009/10 Health Behavior in School-aged Children (HBSC) study. Using multilevel logistic regression analyses, we tested the association between gender inequality and sex differences in health while controlling for country wealth (GDP per capita). Results: In all countries, boys reported more physical fighting, physical activity, and injuries than girls, but the magnitude of these sex differences varied greatly between countries. Societal gender inequality positively related to sex differences in all three outcomes. In more gender unequal countries, boys reported higher levels of fighting and physical activity, compared to boys in more gender equal countries. In girls, scores were consistently low for these outcomes, however injury was more common in countries with less gender inequality. Conclusions: Societal gender inequality appears to relate to sex differences in some adolescent health behaviors and may contribute to the establishment of sex differences in morbidity and mortality. To reduce inequalities in the health of future generations, public health policy should target social and cultural factors that shape perceived gender norms in young people

Long Term Evolution of Massive Black Hole Binaries

The long-term evolution of massive black hole binaries at the centers of galaxies is studied in a variety of physical regimes, with the aim of resolving the ``final parsec problem,'' i.e., how black hole binaries manage to shrink to separations at which emission of gravity waves becomes efficient. A binary ejects stars by the gravitational slingshot and carves out a loss cone in the host galaxy. Continued decay of the binary requires a refilling of the loss cone. We show that the standard treatment of loss cone refilling, derived for collisionally relaxed systems like globular clusters, can substantially underestimate the refilling rates in galactic nuclei. We derive expressions for non-equilibrium loss-cone dynamics and calculate time scales for the decay of massive black hole binaries following galaxy mergers, obtaining significantly higher decay rates than heretofore. Even in the absence of two-body relaxation, decay of binaries can persist due to repeated ejection of stars returning to the nucleus on eccentric orbits. We show that this recycling of stars leads to a gradual, approximately logarithmic dependence of the binary binding energy on time. We derive an expression for the loss cone refilling induced by the Brownian motion of a black hole binary. We also show that numerical N-body experiments are not well suited to probe these mechanisms over long times due to spurious relaxation.Comment: Replaced to match the accepted version, ApJ, 596 (2003

Study of helium transfer technology for STICCR: Fluid management

The Space Infrared Telescope Facility (SIRTF) is a long life cryogenically cooled space based telescope for infrared astronomy from 2 to 700 microns currently under study and planned for launch in the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. Candidates are reviewed for a liquid management device to be used in the resupply of liquid helium, and for the selection of an appropriate candidate

Theory of coherent quantum phase-slips in Josephson junction chains with periodic spatial modulations

We study coherent quantum phase-slips which lift the ground state degeneracy in a Josephson junction ring, pierced by a magnetic flux of the magnitude equal to half of a flux quantum. The quantum phase-slip amplitude is sensitive to the normal mode structure of superconducting phase oscillations in the ring (Mooij-Sch\"on modes). These, in turn, are affected by spatial inhomogeneities in the ring. We analyze the case of weak periodic modulations of the system parameters and calculate the corresponding modification of the quantum phase-slip amplitude

Evolution of the Dark Matter Distribution at the Galactic Center

Annihilation radiation from neutralino dark matter at the Galactic center (GC) would be greatly enhanced if the dark matter were strongly clustered around the supermassive black hole (SBH). The existence of a dark-matter "spike" is made plausible by the observed, steeply-rising stellar density near the GC SBH. Here the time-dependent equations describing gravitational interaction of the dark matter particles with the stars are solved. Scattering of dark matter particles by stars would substantially lower the dark matter density near the GC SBH over 10^10 yr, due both to kinetic heating, and to capture of dark matter particles by the SBH. This result suggests that enhancements in the dark matter density around a SBH would be modest whether or not the host galaxy had experienced the scouring effects of a binary SBH.Comment: 5 pages, 3 figures. Submitted to Physical Review Letter