Noise measurements at Stockton Airport obtained during engineering evaluation of two-segment approaches in a 727-222 aircraft

The results of acoustic measurements made on a 727-222 aircraft during standard ILS and two-segment approaches are presented. The aircraft was equipped with a special purpose glide slope computer to provide the capability of making two-segment noise abatement approaches. For upper segment computations, the computer used barometric-corrected pressure altitude and the slant range to a DME transmitter which was colocated with the glide slope transmitter. The computer used the ILS glide slope deviation for lower segment computations. Additional measurements were made on 737 revenue aircraft using the Stockton Airport. The purpose of the acoustical portion of the test was to measure and identify the noise levels during the various approaches

Noise measurements taken at LAX during operational evaluation of two-segment approaches in a 727-200 aircraft

A series of seven noise measurements were made each day over a period of fifteen days. The first and last flights each day were made by a specially instrumented 727-200 aircraft being used to evaluate the operational effectiveness of two-segment noise abatement approaches in scheduled service. Noise measurements were made to determine the noise reduction benefits of the two-segment approaches

A simple model for DNA denaturation

Following Poland and Scheraga, we consider a simplified model for the denaturation transition of DNA. The two strands are modeled as interacting polymer chains. The attractive interactions, which mimic the pairing between the four bases, are reduced to a single short range binding term. Furthermore, base-pair misalignments are forbidden, implying that this binding term exists only for corresponding (same curvilinear abscissae) monomers of the two chains. We take into account the excluded volume repulsion between monomers of the two chains, but neglect intra-chain repulsion. We find that the excluded volume term generates an effective repulsive interaction between the chains, which decays as $1/r^{d-2}$. Due to this long-range repulsion between the chains, the denaturation transition is first order in any dimension, in agreement with previous studies.Comment: 10 page

AAA gunnermodel based on observer theory

The Luenberger observer theory is used to develop a predictive model of a gunner's tracking response in antiaircraft artillery systems. This model is composed of an observer, a feedback controller and a remnant element. An important feature of the model is that the structure is simple, hence a computer simulation requires only a short execution time. A parameter identification program based on the least squares curve fitting method and the Gauss Newton gradient algorithm is developed to determine the parameter values of the gunner model. Thus, a systematic procedure exists for identifying model parameters for a given antiaircraft tracking task. Model predictions of tracking errors are compared with human tracking data obtained from manned simulation experiments. Model predictions are in excellent agreement with the empirical data for several flyby and maneuvering target trajectories

Effect of natural genetic variation on enhancer selection and function.

The mechanisms by which genetic variation affects transcription regulation and phenotypes at the nucleotide level are incompletely understood. Here we use natural genetic variation as an in vivo mutagenesis screen to assess the genome-wide effects of sequence variation on lineage-determining and signal-specific transcription factor binding, epigenomics and transcriptional outcomes in primary macrophages from different mouse strains. We find substantial genetic evidence to support the concept that lineage-determining transcription factors define epigenetic and transcriptomic states by selecting enhancer-like regions in the genome in a collaborative fashion and facilitating binding of signal-dependent factors. This hierarchical model of transcription factor function suggests that limited sets of genomic data for lineage-determining transcription factors and informative histone modifications can be used for the prioritization of disease-associated regulatory variants

Radiation and String Atmosphere for Relativistic Stars

We extend the Vaidya radiating metric to include both a radiation field and a string fluid. Assuming diffusive transport for the string fluid, we find new analytic solutions of Einstein's field equations. Our new solutions represent an extention of Xanthopoulos superposition.Comment: To appear in Phys. Rev. D, Rapid Communicatio

ISOGAL Survey of Baade's Windows in the Mid-infrared

The ISOGAL mid-infrared survey of areas close to the Galactic Plane aims to determine their stellar content and its possible bearing on the history of the Galaxy. The NGC6522 and Sgr I Baade's Windows of low obscuration towards the inner parts of the Bulge represent ideal places in which to calibrate and understand the ISOGAL colour-magnitude diagrams. The survey observations were made with the ISOCAM instrument of the ISO satellite. The filter bands chosen were LW2(~7 microns) and LW3(~15 microns). The results presented here show that most of the detected objects are late M-type giants on the AGB, with a cut-off for those earlier than M3-M4. The most luminous members of these two Bulge fields at 7 microns are the Mira variables. However, it is evident that they represent the end of a sequence of increasing 15 micron dust emission which commences with M giants of earlier sub-type. In observations of late-type giants the ISOCAM 15 micron band is mainly sensitive to the cool silicate or aluminate dust shells which overwhelm the photospheric emission. However, in ordinary M-giant stars, the 7 micron band is not strongly affected by dust emission and may be influenced instead by absorption. The nu2 band of water at 6.25 microns and the SiO fundamental at 7.9 microns are likely contribitors to this effect. A group of late M stars has been found which vary little or not at all but have infrared colours typical of well-developed dust shells. Their luminosities are similar to those of 200-300 day Miras but they have slightly redder [7]-[15] colours which form an extension of the ordinary M giant sequence. The Mira dust shells show a mid-infrared [7]-[15] colour-period relation. ca 700 days.Comment: 13 pages 15 figure

Fractal Scales in a Schwarzschild Atmosphere

Recently, Glass and Krisch have extended the Vaidya radiating metric to include both a radiation fluid and a string fluid [1999 Class. Quantum Grav. vol 16, 1175]. Mass diffusion in the extended Schwarzschild atmosphere was studied. The continuous solutions of classical diffusive transport are believed to describe the envelope of underlying fractal behavior. In this work we examine the classical picture at scales on which fractal behavior might be evident.Comment: to appear in Class. Quantum Gra

Existence of hysteresis in the Kuramoto model with bimodal frequency distributions

We investigate the transition to synchronization in the Kuramoto model with bimodal distributions of the natural frequencies. Previous studies have concluded that the model exhibits a hysteretic phase transition if the bimodal distribution is close to a unimodal one, due to the shallowness the central dip. Here we show that proximity to the unimodal-bimodal border does not necessarily imply hysteresis when the width, but not the depth, of the central dip tends to zero. We draw this conclusion from a detailed study of the Kuramoto model with a suitable family of bimodal distributions.Comment: 9 pages, 5 figures, to appear in Physical Review