Martin J. Aitken (1922-2017)

No abstract available

Luminescence dating of dune sand and sabkha sediments, Saudi Arabia

32 sediment samples recovered in April 2008 from active and relict dunes, and sabkhas/playas, in Saudi Arabia, were investigated using Optically Stimulated Luminescence (OSL) methods. This work follows an earlier investigation of similar sites over a larger area. The results of the current investigations are reported here. The sabkha and shoreline samples show ages ranging from very modern (with no measurable OSL signal) to 7.6ka, indicating that this study area appears to have some sabkhas significantly younger than those observed in the earlier work. One petrified dune sampled in this work produced an OSL date of 830±210 years, which is consistent with the age ranges of the petrified dunes sampled in the earlier work. Another showed very modern (with no measurable OSL signal) for the indurated sand at the top and an age of 200±150 years for the sand at the back of the dune; another sample taken nearby had an OSL age of 720±180 years. This dune appears to be much younger than the petrified dunes sampled in the previous study. Samples from low-rolling dunes in this study have ages between very modern and 580 years. A barchan dune sample had an age of 60±30 years, similar to ages for barchan dunes sampled in the earlier work. Samples from a low hill had ages of 2.5±0.3 and 5.7±0.5 ka. A buried dune was sampled, producing no measurable natural OSL signal

OSL investigations at Hardisty, Alberta, Canada

This report is concerned with optically stimulated luminescence (OSL) dating investigations of sediments associated with, and enclosing artefacts of First Nations historic significance in the Battle River Valley area, near Hardisty, east central Alberta. The OSL ages reported here provide chronological control to the archaeological investigations at this site, led by Rob Wondrasek, which have identified thousands of historical artefacts, including projectile points and lithic fragments indicative of occupation. The investigations were commissioned by Enbridge, ahead of the construction of the Edmonton-Hardisty Pipeline, and form one part of a historic resources impact assessment study, to characterise the archaeological site, and evaluate/mitigate the impact of the pipeline related excavations. This report describes the background to the investigation, sampling, and luminescence analysis undertaken to generate sediment chronologies for the Hardisty sediment stratigraphies. Ken Munyikwa visited the archaeological investigations at Hardisty in June 2014 to sample key stratigraphic units within the sediment stratigraphies for OSL dating. Samples were collected from two profiles: from strata encompassing the artefact-bearing horizon, and from strata immediately beneath and overlying this horizon, thus providing terminus post quem (TPQ) and terminus ante quem (TAQ) on the age of this unit. Samples were submitted to the luminescence laboratories at SUERC for dating in August 2014. All samples were subjected to laboratory preparation of sand-sized quartz, and purity checked by scanning electron microscopy. Dose rates for the bulk sediment were evaluated using analyses of the uranium, thorium and potassium concentrations obtained by high resolution gamma spectrometry coupled with beta dose rate measurement using thick source beta counting. Equivalent doses were determined by OSL from 64 aliquots of quartz per sample using the quartz single-aliquot-regenerative (SAR) procedure. The material exhibited good OSL sensitivity and produced acceptable SAR internal quality control performance. Dose distributions from the aliquots were examined using radial plotting methods. All samples revealed some heterogeneity in their equivalent dose distribution, reflecting variable bleaching at deposition and indicating that each sample enclosed mixed-age materials. Age estimates were based on the weighted mean estimate of the stored dose, which weights the stored dose estimate towards the lowest population of equivalent doses, potentially representing the better bleached (at deposition) component. The quartz OSL ages reported herein for the sand sequences at Hardisty-1 and Hardisty-2, have provided the first means to assess the temporal distribution of artefacts within the Hardisty profiles, and furthermore provide TPQ and TAQ for the inferred occupational phases. The sediment chronologies established for each profile are internally coherent, spanning at HD-01 from 7.8 ± 0.7 ka (SUTL2692) to 11.7 ± 0.5 ka (SUTL2694), and at HD-02 from 4.5 ± 0.2 ka (SUTL2695) to 8.7 ± 0.5 ka (SUTL2697; Table 4-1). TPQ for the occupation of the Hardisty site is provided by SUTL2697 at 8.7 ± 0.5 ka. TAQ for the occupation of the Hardisty site is provided by SUTL2695 at 4.5 ± 0.2 ka

Action-space clustering of tidal streams to infer the Galactic potential

We present a new method for constraining the Milky Way halo gravitational potential by simultaneously fitting multiple tidal streams. This method requires full three-dimensional positions and velocities for all stars to be fit, but does not require identification of any specific stream or determination of stream membership for any star. We exploit the principle that the action distribution of stream stars is most clustered when the potential used to calculate the actions is closest to the true potential. Clustering is quantified with the Kullback-Leibler Divergence (KLD), which also provides conditional uncertainties for our parameter estimates. We show, for toy Gaia-like data in a spherical isochrone potential, that maximizing the KLD of the action distribution relative to a smoother distribution recovers the true values of the potential parameters. The precision depends on the observational errors and the number of streams in the sample; using KIII giants as tracers, we measure the enclosed mass at the average radius of the sample stars accurate to 3% and precise to 20-40%. Recovery of the scale radius is precise to 25%, and is biased 50% high by the small galactocentric distance range of stars in our mock sample (1-25 kpc, or about three scale radii, with mean 6.5 kpc). About 15 streams, with at least 100 stars per stream, are needed to obtain upper and lower bounds on the enclosed mass and scale radius when observational errors are taken into account; 20-25 streams are required to stabilize the size of the confidence interval. If radial velocities are provided for stars out to 100 kpc (10 scale radii), all parameters can be determined with 10% accuracy and 20% precision (1.3% accuracy in the case of the enclosed mass), underlining the need for ground-based spectroscopic follow-up to complete the radial velocity catalog for faint halo stars observed by Gaia.Comment: Accepted versio

Martin J. Aitken (1922-2017)

No abstract available

Mellie Dunham: A Remembrance Norway Maine Summer Festival, July 2003

The story of Mellie Dunham continues to fascinate, even some seventy-five years after the events. The tale of the 72-year-old country fiddler invited to play for Henry Ford, made famous by the media, then hugely successful as a vaudeville performer, seems almost too perfect to be true. But it all happened, and it was Mellie’s own grace and lack of pretense, a genuineness that inspired the public’s affection for him, that was as much as anything else responsible for the events of 1925 and 1926. This booklet was created to mark Mellie’s 150th birthday, July 29, 2003. We call it a “remembrance”, as being something neither specifically biographical nor specifically historical, but rather a sort of picture of events, relying very much on the words of Mellie and others

Luminescence investigations at Quendale (Broo Peninsula, Shetland)

This report is concerned with optically stimulated luminescence (OSL) investigations of sediment samples collected from ongoing University of Southern Maine archaeological excavations at the Links of Quendale, southern Shetland, investigating the early-modern township of Broo. 11 sediment samples were submitted to the luminescence laboratory at SUERC for OSL dating by Ian Simpson. This report summaries the protocols, and laboratory analysis, employed in quartz single aliquot regenerative (SAR) OSL dating, as used to construct an OSL chronology for wind-blown sands in proximity to the Broo excavations, in association with archaeological structures (5 samples), and for sands in the coastal and inland dune systems (6 samples). The chronology established for the inland sands, in contexts associated with the Broo 2 building and enclosure, spans from AD1540 ± 40 (SUTL2441) through to AD1810 ± 25 (SUTL2519), encompassing the archaeological period of interest. The dates obtained for sands within the enclosed and unenclosed areas to the immediate east and southwest of the excavated Broo site, are AD1760 ± 30 - AD1760 ± 25, and AD1810 ± 25 (SUTL2517-2518 and 2519, respectively), are consistent with the expectation that the clean sands which infill these structures, post-date the period in which the Broo township was abandoned. The coastal sand accumulations, as so far dated, yielded luminescence ages of 2380 ± 230 BC (SUTL2526), 1510 ± 270 BC (SUTL2527), AD 1030 ± 80 (SUTL2528), AD 1690 ± 50 (SUTL2529), AD 1720 ± 20 (SUTL2530) and a mixed-age sample with youngest component at AD 1955 ± 15 (SUTL2531), implying periods of sand mobilisation, synchronous with sand deposition in Orkney and northern Scotland, in the late Neolithic, the Early Bronze Age, the Norse period, the early-modern, and modern periods. This work suggests that the present-day physio-geographical setting of the Quendale Links, comprised of the coastal sand barrier, and the inland dune fields, is a product of a prolonged history of sand mobilisation, erosion and deposition from the Neolithic to the present day. Furthermore, the emerging temporal framework, coupled with the spatial distribution of dune forms across the Links, raises questions as to whether Little Ice Age storms were responsible for deposition, or erosive destruction of older dune-forms, and the re-mobilisation of this sediment. To test these ideas, profiling methods, both field- and laboratory- based, could be employed to obtain a more complete temporal and spatial characterisation of the dune systems and excavated sequences. Further OSL sampling and dating would be needed to define the vertical and lateral chronostratigraphies of the environmental features in the landscape and their relationships to archaeological structures

Music Class Offerings Beyond Bands, Choirs, and Orchestras in Nebraska High Schools

As school music programs in the US evolve and adapt to changing demographics, the types of music courses offered have expanded as well. Today, schools offer more courses in music than just bands, choirs, and orchestras. Music appreciation courses, music technology courses, music theory courses, guitar classes, piano classes, and music composition classes are just a few of the types of music classes that can also be found in American high schools. While high school music class options are becoming more diversified, there has been little research done to profile what kinds of music classes are being offered in schools and how prevalent various music courses are. This thesis sought to describe and profile current music classes that fall outside of band, choral, and orchestral music offerings being taught in high schools, and to describe the experiences of music teachers who’ve developed such music classes within the state of Nebraska. Advisor: Rhonda Fuelbert

Adaptation strategies for self-organising electronic institutions

For large-scale systems and networks embedded in highly dynamic, volatile, and unpredictable environments, self-adaptive and self-organising (SASO) algorithms have been proposed as solutions to the problems introduced by this dynamism, volatility, and unpredictability. In open systems it cannot be guaranteed that an adaptive mechanism that works well in isolation will work well — or at all — in combination with others. In complexity science the emergence of systemic, or macro-level, properties from individual, or micro-level, interactions is addressed through mathematical modelling and simulation. Intermediate meso-level structuration has been proposed as a method for controlling the macro-level system outcomes, through the study of how the application of certain policies, or norms, can affect adaptation and organisation at various levels of the system. In this context, this thesis describes the specification and implementation of an adaptive affective anticipatory agent model for the individual micro level, and a self-organising distributed institutional consensus algorithm for the group meso level. Situated in an intelligent transportation system, the agent model represents an adaptive decision-making system for safe driving, and the consensus algorithm allows the vehicles to self-organise agreement on values necessary for the maintenance of “platoons” of vehicles travelling down a motorway. Experiments were performed using each mechanism in isolation to demonstrate its effectiveness. A computational testbed has been built on a multi-agent simulator to examine the interaction between the two given adaptation mechanisms. Experiments involving various differing combinations of the mechanisms are performed, and the effect of these combinations on the macro-level system properties is measured. Both beneficial and pernicious interactions are observed; the experimental results are analysed in an attempt to understand these interactions. The analysis is performed through a formalism which enables the causes for the various interactions to be understood. The formalism takes into account the methods by which the SASO mechanisms are composed, at what level of the system they operate, on which parts of the system they operate, and how they interact with the population of the system. It is suggested that this formalism could serve as the starting point for an analytic method and experimental tools for a future systems theory of adaptation.Open Acces