High resolution fourier domain optical coherence tomography at 2 microns for painted objects

Optical Coherence Tomography has been successfully applied to the non-invasive imaging of subsurface microstructure of a variety of materials from biological tissues to painted objects of art. One of the limitations of the technique is the low depth of penetration due to the strong scattering and absorption in the material. Previous studies found that for paint materials, the optimum window for large depth of penetration is around 2.2 microns. This is also true for many other materials with low water content. We have previously demonstrated OCT systems in this wavelength regime for imaging with improved depth of penetration. In this paper, we present an improved 2 micron high resolution Fourier domain OCT system using a broadband supercontinuum source. The system achieved a depth resolution of 9 microns in air (or 6 microns in paint or any polymer)

Non-invasive imaging of subsurface paint layers with optical coherence tomography

Optical coherence tomography (OCT) systems are fast scanning infrared Michelson interferometers designed for the non-invasive examination of the interiors of the eye and subsurface structures of biological tissues. OCT has recently been applied to the non-invasive examinations of the stratigraphy of paintings and museum artefacts. So far this is the only technique capable of imaging non-invasively the subsurface structure of paintings and painted objects. Unlike the traditional method of paint cross-section examination where sampling is required, the non-invasive and non-contact nature of the technique enables the examination of the paint cross-section anywhere on a painting, as there is no longer an issue with conservation ethics regarding the taking of samples from historical artefacts. A range of applications of the technique including the imaging of stratigraphy of paintings and painted artefacts, the imaging of underdrawings to the analysis of the optical properties of paint and varnish layers is presented. Future projects on the application of OCT to art conservation are discussed

Applying search theory to determine the feasibility of eradicating an invasive population in natural environments

The detectability of invasive organisms influences the feasibility of eradicating an infestation. Search theory offers a framework for defining and measuring detectability, taking account of searcher ability, biological factors and the search environment. In this paper, search theory concepts are incorporated into a population model, and the costs of search and control are calculated as functions of the amount of search effort (the decision variable). Simulations are performed on a set of weed scenarios in a natural environment, involving different combinations of plant longevity, seed longevity and plant fecundity. Results provide preliminary estimates of the cost and duration of eradication programs to assist in prioritising weeds for control. The analysis shows that the success of an eradication program depends critically on the detectability of the target plant, the effectiveness of the control method, the labour requirements for search and control, and the germination rate of the plant.bioeconomics, invasive species, operations research, population dynamics, weed control, Resource /Energy Economics and Policy,

Weed Search and Control: Theory and Application

The detectability of invasive organisms influences the costs and benefits of alternative control strategies, and the feasibility of eradicating an infestation. Search theory offers a mathematically rigorous framework for defining and measuring detectability, taking account of searcher ability, biological factors and the search environment. To demonstrate the application of search theory to invasive species control, invasive species detectability is incorporated into a population simulation model. The model is applied to a base set of parameter values that represent reasonable values for a hypothetical weed. The analysis shows the effects of detectability and search time on the duration of an eradication program. Furthermore, for a given level of detectability and search time, the analysis shows that the variables with the greatest influence on the duration of the eradication effort are search speed, kill efficiency and seed longevity. A series of Monte Carlo simulations are performed on a set of five scenarios, involving different combinations of plant longevity, seed longevity and plant fecundity. Results of these simulations are presented as probability distributions and allow us to calculate how the probability of eradication will be affected by search strategy.search and control, search theory, weed control, stage matrix, impedance factors, population dynamics, stochastic model, Farm Management,

The bass viol in the mixed consort

A glance at the only surviving printed part-book for the bass viol from the set mixed consort books of Thomas Morley (1599/1611) is rather a disappointment. In many pieces role for that instrument is limited to that of sustaining the bass line of the lute, especially in the repeated passages where the lute is given elaborate divisions. However the manuscript books for the Walsingham Consort Books and more particularly the Cambridge Consort Books associated with Mathew Holmes and Richard Reade reveal a more varied role. In some piece, and especially those of Richard Allison and Daniel Bacheler, the bass viol alternates with the bandora in providing a bass line for subgroupings among the remaining four instruments. As Sydney Beck pointed out in the 1959 introduction to his edition of Morley’s Book, there are a few pieces, notably Lachrimae Pavin and James, His Galliard in the Cambridge Consort bass viol book that give alternative elaborate divisions for the bass viol. This paper explores the musical roles the bass viol is given in the surviving sources of mixed consort music, and considers how the bass viol player might supply simultaneous divisions to enliven the more mundane bass lines of much of the surviving repertoire

Occurrence of a Gynandromorphic Bombus bimaculatus (Hymenoptera: Apidae) in Southeastern Ohio

Herein, we introduce the first reported case of gynandromorphy in the bumblebee Bombus bimaculatus (Cresson) (Hymenoptera: Apidae), a relatively common North American species found east of the Mississippi River. The specimen was collected in Marietta, Ohio as part of a bee diversity assessment project for Washington County. Gynanders exhibit discrete male and female characters in a single individual. We discuss the potential causes of gynandromorphy exhibited by this specimen, which has differing antennal segments (12 and 13), facial maculation, abdominal hair coloration, and the presence of a corbicula – secondary sex characters that are characteristic for the genus Bombus