Renormalisation of supersymmetric gauge theory in the uneliminated component formalism

We show that the renormalisation of the N=1 supersymmetric gauge theory when working in the component formalism, without eliminating auxiliary fields and using a standard covariant gauge, requires a non-linear renormalisation of the auxiliary fields.Comment: 9 pages, including 4 figures. Plain TeX. Uses Harvmac and epsf; reference added and minor changes to Introductio

4D STEM: high efficiency phase contrast imaging using a fast pixelated detector

Phase contrast imaging is widely used for imaging beam sensitive and weak phase objects in electron microscopy. In this work we demonstrate the achievement of high efficient phase contrast imaging in STEM using the pnCCD, a fast direct electron pixelated detector, which records the diffraction patterns at every probe position with a speed of 1000 to 4000 frames per second, forming a 4D STEM dataset simultaneously with the incoherent Z-contrast imaging. Ptychographic phase reconstruction has been applied and the obtained complex transmission function reveals the phase of the specimen. The results using GaN and Ti, Nd- doped BiFeO3 show that this imaging mode is especially powerful for imaging light elements in the presence of much heavier elements

Rectifying fluctuations in an optical lattice

We have realized a Brownian motor by using cold atoms in a dissipative optical lattice as a model system. In our experiment the optical potential is spatially symmetric and the time-symmetry of the system is broken by applying appropriate zero-mean ac forces. We identify a regime of rectification of forces and a regime of rectification of fluctuations, the latter corresponding to the realization of a Brownian motor

Two new ultracool benchmark systems from WISE+2MASS

We have used the Two-Micron All-Sky Survey and the Wide-field Infrared Survey Explorer to look for ultracool dwarfs that are part of multiple systems containing main-sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding two new systems. The first system, G255-34AB, is an L2 dwarf companion to a K8 star, at a distance of 36 pc. We estimate its bolometric luminosity as log L/L-circle dot = -3.78 +/- 0.045 and T-eff = 2080 +/- 260 K. The second system, GJ499ABC, is a triple, with an L5 dwarf as a companion to a binary with an M4 and K5 star. These two new systems bring the number of L dwarf plus main-sequence star multiple systems to 24, which we discuss. We consider the binary fraction for L dwarfs and main-sequence stars, and further assess possible unresolved multiplicity within the full companion sample. This analysis shows that some of the L dwarfs in this sample might actually be unresolved binaries themselves, since their M-J appears to be brighter than the expected for their spectral types.Peer reviewe

Order parameter in superconductors with non-degenerate bands

In noncentrosymmetric metals, the spin degeneracy of the electronic bands is lifted by spin-orbit coupling. We consider general symmetry properties of the pairing function Delta(k) in noncentrosymmetric superconductors with spin-orbit coupling (NSC), including CePt3Si, UIr and Cd2Re2O7. We find that Delta(k) = chi(k) t(k), where chi(k) is an even function which transforms according to the irreducible representations of the crystallographic point group and t(k) is a model dependent phase factor. We consider tunnelling between a NSC and a conventional superconductor. It is found that, in terms of thermodynamical properties as well as the Josephson effect, the state of NSC resembles a singlet superconducting state with gap function chi(k).Comment: 8 pages, references updated. Accepted to PR

Infrared luminosities of galaxies in the Local Volume

Near-infrared properties of 451 galaxies with distances D \leq 10 Mpc are considered basing on the all-sky two micron survey (2MASS). A luminosity function of the galaxies in the K-band is derived within [-25,-11] mag. The local (D < 8 Mpc) luminosity density is estimated to be 6.8*10^8 L_sun/Mpc^3 that exceeds (1.5+-0.1) times the global cosmic density in the K-band. Virial mass-to-K-luminosity ratios are determined for nearby groups and clusters. In the luminosity range of (5*10^{10} - 2*10^{13})L_sun, the groups and clusters follow the relation \lg(M/L_K) propto (0.27+-0.03) lg(L_K) with a scatter of \~0.1 comparable to errors of the observables. The mean ratio ~= (20-25) M_sun/L_sun for the galaxy systems turns out to be significantly lower than the global ratio, (80-90)M_sun/L_sun, expected in the standard cosmological model with the matter density of Omega_m =0.27. This discrepancy can be resolved if most of dark matter in the universe is not associated with galaxies and their systems.Comment: 15 pages, 7 figures. Astronomy Letters, submitte

Synthetic Observations of Simulated Radio Galaxies I: Radio and X-ray Analysis

We present an extensive synthetic observational analysis of numerically- simulated radio galaxies designed to explore the effectiveness of conventional observational analyses at recovering physical source properties. These are the first numerical simulations with sufficient physical detail to allow such a study. The present paper focuses on extraction of magnetic field properties from nonthermal intensity information. Synchrotron and inverse-Compton intensities provided meaningful information about distributions and strengths of magnetic fields, although considerable care was called for. Correlations between radio and X-ray surface brightness correctly revealed useful dynamical relationships between particles and fields. Magnetic field strength estimates derived from the ratio of X-ray to radio intensity were mostly within about a factor of two of the RMS field strength along a given line of sight. When emissions along a given line of sight were dominated by regions close to the minimum energy/equipartition condition, the field strengths derived from the standard power-law-spectrum minimum energy calculation were also reasonably close to actual field strengths, except when spectral aging was evident. Otherwise, biases in the minimum- energy magnetic field estimation mirrored actual differences from equipartition. The ratio of the inverse-Compton magnetic field to the minimum-energy magnetic field provided a rough measure of the actual total energy in particles and fields in most instances, within an order of magnitude. This may provide a practical limit to the accuracy with which one may be able to establish the internal energy density or pressure of optically thin synchrotron sources.Comment: 43 pages, 14 figures; accepted for publication in ApJ, v601 n2 February 1, 200

FirstLight: Pluggable Optical Interconnect Technologies for Polymeric Electro-Optical Printed Circuit Boards in Data Centers

The protocol data rate governing data storage devices will increase to over 12 Gb/s by 2013 thereby imposing unmanageable cost and performance burdens on future digital data storage systems. The resulting performance bottleneck can be substantially reduced by conveying high-speed data optically instead of electronically. A novel active pluggable 82.5 Gb/s aggregate bit rate optical connector technology, the design and fabrication of a compact electro-optical printed circuit board to meet exacting specifications, and a method for low cost, high precision, passive optical assembly are presented. A demonstration platform was constructed to assess the viability of embedded electro-optical midplane technology in such systems including the first ever demonstration of a pluggable active optical waveguide printed circuit board connector. High-speed optical data transfer at 10.3125 Gb/s was demonstrated through a complex polymer waveguide interconnect layer embedded into a 262 mm × 240 mm × 4.3 mm electro-optical midplane. Bit error rates of less than 10-12 and optical losses as low as 6 dB were demonstrated through nine multimode polymer wave guides with an aggregate data bandwidth of 92.8125 Gb/s

Increasing compliance with low tidal volume ventilation in the ICU with two nudge-based interventions: evaluation through intervention time-series analyses

Objectives: Low tidal volume (TVe) ventilation improves outcomes for ventilated patients, and the majority of clinicians state they implement it. Unfortunately, most patients never receive low TVes. ‘Nudges’ influence decision-making with subtle cognitive mechanisms and are effective in many contexts. There have been few studies examining their impact on clinical decision-making. We investigated the impact of 2 interventions designed using principles from behavioural science on the deployment of low TVe ventilation in the intensive care unit (ICU). Setting: University Hospitals Bristol, a tertiary, mixed medical and surgical ICU with 20 beds, admitting over 1300 patients per year. Participants: Data were collected from 2144 consecutive patients receiving controlled mechanical ventilation for more than 1 hour between October 2010 and September 2014. Patients on controlled mechanical ventilation for more than 20 hours were included in the final analysis. Interventions: (1) Default ventilator settings were adjusted to comply with low TVe targets from the initiation of ventilation unless actively changed by a clinician. (2) A large dashboard was deployed displaying TVes in the format mL/kg ideal body weight (IBW) with alerts when TVes were excessive. Primary outcome measure: TVe in mL/kg IBW. Findings: TVe was significantly lower in the defaults group. In the dashboard intervention, TVe fell more quickly and by a greater amount after a TVe of 8 mL/kg IBW was breached when compared with controls. This effect improved in each subsequent year for 3 years. Conclusions: This study has demonstrated that adjustment of default ventilator settings and a dashboard with alerts for excessive TVe can significantly influence clinical decision-making. This offers a promising strategy to improve compliance with low TVe ventilation, and suggests that using insights from behavioural science has potential to improve the translation of evidence into practice

Anomalous Thermal Stability of Metastable C_20 Fullerene

The results of computer simulation of the dynamics of fullerene C_20 at different temperatures are presented. It is shown that, although it is metastable, this isomer is very stable with respect to the transition to a lower energy configuration and retains its chemical structure under heating to very high temperatures, T ~ 3000 K. Its decay activation energy is found to be E_a ~ 7 eV. Possible decay channels are studied, and the height of the minimum potential barrier to decay is determined to be U = 5.0 eV. The results obtained make it possible to understand the reasons for the anomalous stability of fullerene C_20 under normal conditions.Comment: Slightly corrected version of the paper submitted to Phys. Solid Stat