Scientists, engineers and managers - Partners in space

Management practices in aerospace industr

Rare Dark American Kestrel – Melanistic or Sooty?

On April 13 in Seward County, we noticed a dark bird flying relatively low over fields east of Seward near 224th and Bluff Rd. Initially, because of its size, dark coloration and pointed wingtips, we were unsure of its identification and followed the bird to get better looks and identify it. We were able to observe and photograph the bird perched (Figure 1). We also observed the bird hovering and diving to the ground multiple times in search of prey. After better looks, based on size, wing shape, hooked beak, claws, and behavior (repeated hovering over field), we concluded the bird was an American Kestrel (Falco sparverius). Joel and Camden returned later in the day and were able to relocate the bird. Camden got photos of the kestrel in flight showing additional details (Figure 2). We believe the observed bird was a female based on barring in the tail. As can be seen in the photos, the head and body patterns normally seen in American Kestrels are absent. Barring can be seen in both the underwings and the tail (Figures 1 and 2) while light-colored feathers are visible in the vent and belly. Both the cere and feet are yellow/orange normally seen in kestrels. Initially, we thought the bird was a melanistic American Kestrel. There is widespread misunderstanding about the causes of dark coloration in birds (Davis 2007; van Grouw 2017), so we shared the photos with people who had studied dark coloration in birds. Some believed the bird was melanistic and others believed it was soot-covered. We will discuss both below

Integrating horizon scanning and strategic risk prioritisation using a weight of evidence framework to inform policy decisions

Poor connection between data on emerging issues and credible policy decisions continues to challenge governments, and is only likely to grow as demands on time and resources increase. Here we summarise recent efforts to integrate horizon scanning and risk prioritisation approaches to better connect emerging issues to the political discourse on environmental and food-related issues. Our categorisation of insights including potential future risks and opportunities to inform policy discussions has emerged from a structured three-year programme of horizon scanning for a UK pan-governmental futures partnership led by the Department for Environment, Food and Rural Affairs (Defra). Our efforts to integrate horizon scanning and risk prioritisation, utilising a qualitative weight of evidence framework, has created a systematic process for identifying all signals of potential future change with significant impact for the strategic mission and underlying values of policy actors. Our approach encourages an exploration of factors out of the control of organisations, recognising that resilience depends on the flexibility of management strategies and the preparedness to deal with a variety of unexpected outcomes. We discuss how this approach addresses key cultural and evaluative challenges that policy actors have had in embedding horizon scanning in evidence-based policy processes, and suggest further developments to build confidence in the use of horizon scanning for strategic planning

Two-photon diffraction and quantum lithography

We report a proof-of-principle experimental demonstration of quantum lithography. Utilizing the entangled nature of a two-photon state, the experimental results have bettered the classical diffraction limit by a factor of two. This is a quantum mechanical two-photon phenomenon but not a violation of the uncertainty principle.Comment: 5 pages, 5 figures Submitted to Physical Review Letter

Quantum Imaging

We provide a brief overview of the newly born field of quantum imaging, and discuss some concepts that lie at the root of this field.Comment: 8 pages, 19 figure

Relativistic precession and spin dynamics of an elliptic Rydberg wave packet

Time evolution of wave packets built from the eigenstates of the Dirac equation for a hydrogenic system is considered. We investigate the space and spin motion of wave packets which, in the non-relativistic limit, are stationary states with a probability density distributed uniformly along the classical, elliptical orbit (elliptic WP). We show that the precession of such a WP, due to relativistic corrections to the energy eigenvalues, is strongly correlated with the spin motion. We show also that the motion is universal for all hydrogenic systems with an arbitrary value of the atomic number Z.Comment: Latex2e, uses IOP style files (included), 10 pages, 5 jpg figures, 1 postscript figure. Relation between precession time and radiative liftime added (eq.(12)). Accepted for publication in J. Phys.

Efficient generation of correlated photon pairs in a microstructure fiber

We report efficient generation of correlated photon pairs through degenerate four-wave mixing in microstructure fibers. With 735.7 nm pump pulses producing conjugate signal (688.5 nm) and idler (789.8 nm) photons in a 1.8 m microstructure fiber, we detect photon pairs at a rate of 37.6 kHz with a coincidence/accidental contrast of 10:1 with a full-width-at-half-maximum bandwidth of 0.7 nm. This is the highest rate reported to date in a fiber-based photon source. The nonclassicality of this source, as defined by the Zou-Wang-Mandel inequality, is violated by 1100 times the uncertainty.Comment: 11 pages, 3 figure

Spin and magnetization effects in plasmas

We give a short review of a number of different models for treating magnetization effects in plasmas. In particular, the transition between kinetic models and fluid models is discussed. We also give examples of applications of such theories. Some future aspects are discussed.Comment: 18 pages, 1 figure. To appear in Plasma Physics and Controlled Fusion, Special Issue for the 37th ICPP, Santiago, Chil

Relativistic treatment of harmonics from impurity systems in quantum wires

Within a one particle approximation of the Dirac equation we investigate a defect system in a quantum wire. We demonstrate that by minimally coupling a laser field of frequency omega to such an impurity system, one may generate harmonics of multiples of the driving frequency. In a multiple defect system one may employ the distance between the defects in order to tune the cut-off frequency.Comment: 9 pages Latex, 8 eps figures, section added, numerics improve