Renormalization effects on neutrino masses and mixing in a string-inspired SU(4) X SU(2)_L X SU(2)_R X U(1)_X model

We discuss renormalization effects on neutrino masses and mixing angles in a supersymmetric string-inspired SU(4) X SU(2)_L X SU(2)_R X U(1)_X model, with matter in fundamental and antisymmetric tensor representations and singlet Higgs fields charged under the anomalous U(1)_X family symmetry. The quark, lepton and neutrino Yukawa matrices are distinguished by different Clebsch-Gordan coefficients. The presence of a second U(1)_X breaking singlet with fractional charge allows a more realistic, hierarchical light neutrino mass spectrum with bi-large mixing. By numerical investigation we find a region in the model parameter space where the neutrino mass-squared differences and mixing angles at low energy are consistent with experimental data.Comment: 9 pages, 7 figures; references adde

Biomechanical Similarities And Differences Of A. Agassi's First And Second Serves

The purpose of this study was to perform three-dimensional analysis of the instrumentally recorded elements of Andre Agassi's serving technique during competition. A video based analysis system was used to analyze the data provided by two sVHS (60 Hz) back and right side view camcorders. Four successful first and second serves into the deuce court were selected for the analysis. Spatial kinematic characteristics of the defined points and segments were analyzed. The average speed of the ball for the first serve was 45.8±2.2 m/s and angled close to the sideline. The second serve was hit with pronounced topspin and achieved a ball speed of 37.9±2.4 m/s. Kinematic characteristics of the CG in the preparation phase reflects direction, velocity and rotation of the ball. The first serve's CG maximum speed was 1.89±0.10 m/s. Angle ofthe horizontal velocity at the moment of impact was 17±4 degrees. The characteristics of the second serve were 1.71±0.09 m/sand 1l±5 degrees. However, the vertical component of CG velocity of the second serve was 12% higher than the first which most likely provided additional ball rotation. The ball positioning relative to the CG at the moment of impact for the first serve was 0.13±0.02 m forward and 0.12±0.04 m laterally. The second serve had no significant forward shift between the ball and CG. Lateral shift was 0.36±0.04 m. The impact height was relatively the same. Analysis of body segment movements during the first serve gives the following results: high speed right knee extension, hip and shoulder rotation provides pronounced forward body motion. In the second serve extension of the left knee was dominant with less influence by the hip and shoulder rotation, but with more notable lateral trunk action. No significant differences were found between right arm and racquet's relative movements during the first and the second serves. In both cases maximum angular velocities of the elbow extension and a racquet swing were 1185±110 deg/s and 3240±180 deg/sec respectively with the same structure of the velocity changes. It was found that in order to increase consistency of the second serve, Agassi while keeping the relative motion of his arm consistent from serve to serve, makes changes in his vertical and lateral position, and the forward motion of his body which causes changes in the velocity and rotation of the ball. Since the torso and leg muscles are larger than the arm muscles, they are stronger and more stable, thus providing consistency in changes of motion patterns for the second serve

Sub-millimeter images of a dusty Kuiper belt around eta Corvi

We present sub-millimeter and mid-infrared images of the circumstellar disk around the nearby F2V star eta Corvi. The disk is resolved at 850um with a size of ~100AU. At 450um the emission is found to be extended at all position angles, with significant elongation along a position angle of 130+-10deg; at the highest resolution (9.3") this emission is resolved into two peaks which are to within the uncertainties offset symmetrically from the star at 100AU projected separation. Modeling the appearance of emission from a narrow ring in the sub-mm images shows the observed structure cannot be caused by an edge-on or face-on axisymmetric ring; the observations are consistent with a ring of radius 150+-20AU seen at 45+-25deg inclination. More face-on orientations are possible if the dust distribution includes two clumps similar to Vega; we show how such a clumpy structure could arise from the migration over 25Myr of a Neptune mass planet from 80-105AU. The inner 100AU of the system appears relatively empty of sub-mm emitting dust, indicating that this region may have been cleared by the formation of planets, but the disk emission spectrum shows that IRAS detected an additional hot component with a characteristic temperature of 370+-60K (implying a distance of 1-2AU). At 11.9um we found the emission to be unresolved with no background sources which could be contaminating the fluxes measured by IRAS. The age of this star is estimated to be ~1Gyr. It is very unusual for such an old main sequence star to exhibit significant mid-IR emission. The proximity of this source makes it a perfect candidate for further study from optical to mm wavelengths to determine the distribution of its dust.Comment: 22 pages, 4 figures. Scheduled for publication in ApJ 10 February 2005 issu

Herschel PACS Observations and Modeling of Debris Disks in the Tucana-Horologium Association

We present Herschel PACS photometry of seventeen B- to M-type stars in the 30 Myr-old Tucana-Horologium Association. This work is part of the Herschel Open Time Key Programme "Gas in Protoplanetary Systems" (GASPS). Six of the seventeen targets were found to have infrared excesses significantly greater than the expected stellar IR fluxes, including a previously unknown disk around HD30051. These six debris disks were fitted with single-temperature blackbody models to estimate the temperatures and abundances of the dust in the systems. For the five stars that show excess emission in the Herschel PACS photometry and also have Spitzer IRS spectra, we fit the data with models of optically thin debris disks with realistic grain properties in order to better estimate the disk parameters. The model is determined by a set of six parameters: surface density index, grain size distribution index, minimum and maximum grain sizes, and the inner and outer radii of the disk. The best fitting parameters give us constraints on the geometry of the dust in these systems, as well as lower limits to the total dust masses. The HD105 disk was further constrained by fitting marginally resolved PACS 70 micron imaging.Comment: 15 pages, 7 figures, Accepted to Ap

Structure and effects of annealing in colloidal matrix-free Ge quantum dots

This research was supported by Queen Mary, University of London. We would like to thank Diamond synchrotron light source for the beamline (B18) and the corporation work. AK and OE acknowledge the Turkish Ministry of National Education. WL is grateful to the South East Physics Network (SEPnet). YZ was supported by Chinese Scholarship Council (CSC) for PhD study

Atomic environments in iron meteorites using EXAFS

Extended x ray absorption fine structure (EXAFS) is observed as a modulation on the high energy side of an x ray absorption edge. It occurs when the photo-ejected electron wave is scattered by neighboring atoms in a solid, and interference occurs between the outgoing and scattered waves. The result is that the absorption spectrum carries a signature that is characteristic of the identity and disposition of scattering atoms around the absorbing atom. Therefore, it may be shown that the Fourier transform of the normalized EXAFS can provide detailed information about the immediate environment of specific atoms in a solid and is ideally suited to the study of cosmic dusts. A study of cosmic dust was initiated using EXAFS and other techniques. The simplest type of cosmic material, namely iron meteorites, was investigated

Dust in the 55 Cancri planetary system

The presence of debris disks around $\sim$ 1-Gyr-old main sequence stars suggests that an appreciable amount of dust may persist even in mature planetary systems. Here we report the detection of dust emission from 55 Cancri, a star with one, or possibly two, planetary companions detected through radial velocity measurements. Our observations at 850$\mu$m and 450$\mu$m imply a dust mass of 0.0008-0.005 Earth masses, somewhat higher than that in the the Kuiper Belt of our solar system. The estimated temperature of the dust grains and a simple model fit both indicate a central disk hole of at least 10 AU in radius. Thus, the region where the planets are detected is likely to be significantly depleted of dust. Our results suggest that far-infrared and sub-millimeter observations are powerful tools for probing the outer regions of extrasolar planetary systems.Comment: 8 pages and 2 figures, to appear in the Astrophysical Journa

Extending the PyCBC search for gravitational waves from compact binary mergers to a global network

The worldwide advanced gravitational-wave (GW) detector network has so far primarily consisted of the two Advanced LIGO observatories at Hanford and Livingston, with Advanced Virgo joining the 2016-7 O2 observation run at a relatively late stage. However Virgo has been observing alongside the LIGO detectors since the start of the O3 run; in the near future, the KAGRA detector will join the global network and a further LIGO detector in India is under construction. Gravitational-wave search methods would therefore benefit from the ability to analyse data from an arbitrary network of detectors. In this paper we extend the PyCBC offline compact binary coalescence (CBC) search analysis to three or more detectors, and describe resulting updates to the coincident search and event ranking statistic. For a three-detector network, our improved multi-detector search finds 20% more simulated signals at fixed false alarm rate in idealized colored Gaussian noise, and up to 40% more in real data, compared to the two-detector analysis previously used during O2

A combinatorial nanoprecursor route for direct solid state chemistry: Discovery and electronic properties of new iron-doped lanthanum nickelates up to La4Ni2FeO10-delta

We describe a simple nanoprecursor route for direct solid-state combinatorial synthesis and discovery of heterometallic materials compositions which are normally difficult to make in a single step. Using a combinatorial robot (incorporating a continuous hydrothermal reactor), co-precipitated nanoprecursors containing different amounts of La, Ni and Fe oxides were made. These samples were divided into two identical cloned libraries, which were heat-treated to bring about solid-state transformations at either 1348 K or 1573 K for 12 h. In each case, experimental conditions were designed to form the corresponding La4Ni3 − xFexO10 phases (x = 0.0–3.0) directly without comminution. Such materials are difficult to make without multiple heating and grinding steps. The heat-treated samples from each library were embedded into a wellplate and analysed by powder X-ray diffraction methods in order to elucidate trends in phase behaviour. Several hitherto unknown phase-pure Ruddlesden Popper type La4Ni3 − xFexO10 compositions were identified and their DC electrical conductivities measured