Assessment of a wake vortex flight test program

A proposed flight test program to measure the characteristics of wake vortices behind a T-33 aircraft was investigated. A number of facets of the flight tests were examined to define the parameters to be measured, the anticipated vortex characteristics, the mutual interference between the probe aircraft and the wake, the response of certain instruments to be used in obtaining measurements, the effect of condensation on the wake vortices, and methods of data reduction. Recommendations made as a result of the investigation are presented

Emotional and Adrenocortical Responses of Infants to the Strange Situation: The Differential Function of Emotional Expression

The aim of the study was to investigate biobehavioural organisation in infants with different qualities of attachment. Quality of attachment (security and disorganisation), emotional expression, and adrenocortical stress reactivity were investigated in a sample of 106 infants observed during Ainsworth’s Strange Situation at the age of 12 months. In addition, behavioural inhibition was assessed from maternal reports. As expected, securely attached infants did not show an adrenocortical response. Regarding the traditionally defined insecurely attached groups, adrenocortical activation during the strange situation was found for the ambivalent group, but not for the avoidant one. Previous ndings of increased adrenocortical activity in disorganised infants could not be replicated. In line with previous ndings, adrenocortical activation was most prominent in insecure infants with high behavioural inhibition indicating the function of a secure attachment relationship as a social buffer against less adaptive temperamental dispositions. Additional analyses indicated that adrenocortical reactivity and behavioural distress were not based on common activation processes. Biobehavioural associations within the different attachment groups suggest that biobehavioural processes in securely attached infants may be different from those in insecurely attached and disorganised groups. Whereas a coping model may be applied to describe the biobehavioural organisation of secure infants, an arousal model explanation may be more appropriate for the other groups

Limits on Enhanced Radio Wave Scattering by Supernova Remnants

We report multifrequency observations with the NRAO Very Long Baseline Array (VLBA) of the compact radio sources J0128+6306 and J0547+2721, which are viewed through the supernova remnants G127.1+0.5 and S147, respectively. Observations were made at frequencies of 1.427, 1.667, 2.271, and 4.987 GHz. The lines of sight to these sources pass through the shock wave and upstream and downstream turbulent layers of their respective supernova remnants, and thus might detect cosmic-ray generated turbulence produced during the Fermi acceleration process. For both sources, we detect interstellar scattering, characterized by a component of the angular size which scales as the square of the observing wavelength. The magnitude of the scattering is characterized by an effective scattering angular size theta_S0 at a frequency of 1 GHz of 13.2 +/- 2.6 milliarcseconds (mas) for J0128+6306 and 6.7 +/- 2.2 mas for J0547+2721. These angular sizes are consistent with the ``incidental'' scattering for any line of sight out of the galaxy at similar galactic latitudes and longitudes. There is therefore no evidence for enhanced turbulence at these supernova remnants. We establish upper limits to the supernova remnant-associated scattering measures of 8.1-14.8 m^-20/3-pc for J0128+6306 and 3.0 m^-20/3-pc for J0547+2721.Comment: To be published in ApJ, 25 pages, 4 figures, 2 table

Genome-wide association study of Stayability and Heifer Pregnancy in Red Angus cattle

Reproductive performance is the most important component of cattle production from the standpoint of economic sustainability of commercial beef enterprises. Heifer Pregnancy (HPG) and Stayability (STAY) genetic predictions are 2 selection tools published by the Red Angus Association of America (RAAA) to assist with improvements in reproductive performance. Given the importance of HPG and STAY to the profitability of commercial beef enterprises, the objective of this study was to identify QTL associated with both HPG and STAY in Red Angus cattle. A genome-wide association study (GWAS) was performed using deregressed HPG and STAY EBV, calculated using a single-trait animal model and a 3-generation pedigree with data from the Spring 2015 RAAA National Cattle Evaluation. Each individual animal possessed 74,659 SNP genotypes. Individual animals with a deregressed EBV reliability \u3e 0.05 were merged with the genotype file and marker quality control was performed. Criteria for sifting genotypes consisted of removing those markers where any of the following were found: average call rate less than 0.85, minor allele frequency \u3c 0.01, lack of Hardy–Weinberg equilibrium (P \u3c 0.0001), or extreme linkage disequilibrium (r2 \u3e 0.99). These criteria resulted in 2,664 animals with 62,807 SNP available for GWAS. Association studies were performed using a Bayes Cπ model in the BOLT software package. Marker significance was calculated as the posterior probability of inclusion (PPI), or the number of instances a specific marker was sampled divided by the total number of samples retained from the Markov chain Monte Carlo chains. Nine markers, with a PPI ≥ 3% were identified as QTL associated with HPG on BTA 1, 11, 13, 23, and 29. Twelve markers, with a PPI ≥ 75% were identified as QTL associated with STAY on BTA 6, 8, 9, 12, 15, 18, 22, and 23

The Galactic Distribution of Large HI Shells

We report the discovery of nineteen new HI shells in the Southern Galactic Plane Survey (SGPS). These shells, which range in radius from 40 pc to 1 kpc, were found in the low resolution Parkes portion of the SGPS dataset, covering Galactic longitudes l=253 deg to l=358 deg. Here we give the properties of individual shells, including positions, physical dimensions, energetics, masses, and possible associations. We also examine the distribution of these shells in the Milky Way and find that several of the shells are located between the spiral arms of the Galaxy. We offer possible explanations for this effect, in particular that the density gradient away from spiral arms, combined with the many generations of sequential star formation required to create large shells, could lead to a preferential placement of shells on the trailing edges of spiral arms. Spiral density wave theory is used in order to derive the magnitude of the density gradient behind spiral arms. We find that the density gradient away from spiral arms is comparable to that out of the Galactic plane and therefore suggest that this may lead to exaggerated shell expansion away from spiral arms and into interarm regions.Comment: 25 pages, 20 embedded EPS figures, uses emulateapj.sty, to appear in the Astrophysical Journa

Ursinus College Bulletin Vol. 9, No. 5, February 1893

A digitized copy of the February 1893 Ursinus College Bulletin.https://digitalcommons.ursinus.edu/ucbulletin/1083/thumbnail.jp

Two-soliton solution for the derivative nonlinear Schr\"odinger equation with nonvanishing boundary conditions

An explicit two-soliton solution for the derivative nonlinear Schr\"odinger equation with nonvanishing boundary conditions is derived, demonstrating details of interactions between two bright solitons, two dark solitons, as well as one bright soliton and one dark soliton. Shifts of soliton positions due to collisions are analytically obtained, which are irrespective of the bright or dark characters of the participating solitons.Comment: 11 pages, 4 figures. Phys. Lett. A 2006 (in press

The spectra and energies of classical double radio lobes

We compare two temporal properties of classical double radio sources: i) radiative lifetimes of synchrotron-emitting particles and ii) dynamical source ages. We discuss how these can be quite discrepant from one another, rendering use of the traditional spectral ageing method inappropriate: we contend that spectral ages give meaningful estimates of dynamical ages only when these ages are << 10^7 years. In juxtaposing the fleeting radiative lifetimes with source ages which are significantly longer, a refinement of the paradigm for radio source evolution is required. The changing spectra along lobes are explained, not predominantly by synchrotron ageing but, by gentle gradients in a magnetic field mediated by a low-gamma matrix which illuminates an energy-distribution of particles, controlled largely by classical synchrotron loss in the high magnetic field of the hotspot. The energy in the particles is an order of magnitude higher than that inferred from the minimum-energy estimate, implying that the jet-power is of the same order as the accretion luminosity produced by the quasar central engine. This refined paradigm points to a resolution of the findings of Rudnick et al (1994) and Katz-Stone & Rudnick (1994) that both the Jaffe-Perola and Kardashev-Pacholczyk model spectra are invariably poor descriptions of the curved spectral shape of lobe emission, and indeed that for Cygnus A all regions of the lobes are characterised by a `universal spectrum'. [abridged]Comment: LaTeX, 4 figures. To appear in A