Volumetric visualization of 3D data

In recent years, there has been a rapid growth in the ability to obtain detailed data on large complex structures in three dimensions. This development occurred first in the medical field, with CAT (computer aided tomography) scans and now magnetic resonance imaging, and in seismological exploration. With the advances in supercomputing and computational fluid dynamics, and in experimental techniques in fluid dynamics, there is now the ability to produce similar large data fields representing 3D structures and phenomena in these disciplines. These developments have produced a situation in which currently there is access to data which is too complex to be understood using the tools available for data reduction and presentation. Researchers in these areas are becoming limited by their ability to visualize and comprehend the 3D systems they are measuring and simulating

Precautionary Saving and the Timing of Taxes

This paper analyzes the effects of government debt and income taxes on consumption and saving in a world of infinitely-lived households having uncertain and heterogeneous incomes. The special structure of the model allows exact aggregation across households despite incomplete markets. The effects of government debt are shown to be substantial, roughly comparable to those resulting from finite horizons, and crucially dependent on the length of time until the debt is repaid. Also, anticipated changes in taxes are shown to cause anticipated changes in consumption. Finally, an index of fiscal stance is derived.

Doctor of Philosophy

dissertationImpairment in language and communication is a core deficit in autism and related autism spectrum disorders. Relatively recent research supports a co-occurrence of language impairment similar to that seen in children with structural language impairments and autism spectrum disorders. While it is not clear whether this impairment constitutes a subtype of children with autism or a convergence between two distinct disorders, language impairment is emerging as an important dimension in understanding autism spectrum disorders. In the current study, Profile Analysis via Multidimensional Scaling (PAMS) was used to create communication profiles, which were then validated in a sample of school aged children from a local school district receiving services through Special Education under the educational classification of Autism. Three profiles were supported: High Speech vs. Low Nonverbal Communication, High Syntax vs. Low Context, and High Scripted Language vs. Low Social Relations. These communication profiles were correlated with external variables including measures of adaptive functioning, cognitive ability, language ability, and autism symptoms. High Speech vs. Low Nonverbal Communication showed significant positive correlations on most external variables, while neither of the other two profiles showed significant correlations with any of the external measures. Characteristics of good fit to the profiles as well as profile differences in children identified as having structural language impairments are discussed

Assessing the Production Scale and Research and Extension Needs of U.S. Hard Cider Producers

At CiderCON 2013 and 2014, we assessed the scale of current and projected production, as well as the research and Extension needs of cider apple growers and cider makers. Our findings show that cider producers are diverse in terms of geographic location, scale of operation, and experience. These stakeholders reported a great need for technical assistance from Extension professionals and were interested in having information delivered in a wide range of different platforms. We also found audience response devices to be effective at quickly gathering and analyzing data from a large number of participants

Thermal Design Considerations of the Robotic Refueling Mission (RRM)

The Robotic Refueling Mission (RRM) is a flight demonstration of the tasks required to perform robotic refueling of orbiting spacecraft. RRM will be mounted to an ExPress Adapter Plate (ExPA) for launch and installed onto the International Space Station (ISS) Express Logistics Carrier 4 (ELC4). RRM operations will be conducted using the Special Purpose Dexterous Manipulator (SPDM) robotic arm on the ISS with the ORU/Tool Changeout Mechanism (OTCM) for grasping tools and completing the refueling demonstration tasks. This paper presents the thermal considerations and design of the RRM including the tools required for the tasks

Thin Sectioning of Slice Preparations for Immunohistochemistry

Many investigations in neuroscience, as well as other disciplines, involve studying small, yet macroscopic pieces or sections of tissue that have been preserved, freshly removed, or excised but kept viable, as in slice preparations of brain tissue. Subsequent microscopic studies of this material can be challenging, as the tissue samples may be difficult to handle. Demonstrated here is a method for obtaining thin cryostat sections of tissue with a thickness that may range from 0.2-5.0 mm. We routinely cut 400 micron thick Vibratome brain slices serially into 5-10 micron coronal cryostat sections. The slices are typically first used for electrophysiology experiments and then require microscopic analysis of the cytoarchitecture of the region from which the recordings were observed. We have constructed a simple device that allows controlled and reproducible preparation and positioning of the tissue slice. This device consists of a cylinder 5 cm in length with a diameter of 1.2 cm, which serves as a freezing stage for the slice. A ring snugly slides over the cylinder providing walls around the slice allowing the tissue to be immersed in freezing compound (e.g., OCT). This is then quickly frozen with crushed dry ice and the resulting wafer can be position easily for cryostat sectioning. Thin sections can be thaw-mounted onto coated slides to allow further studies to be performed, such as various staining methods, in situ hybridization, or immunohistochemistry, as demonstrated here

Precautionary Saving and the Timing of Taxes

This paper analyzes the effects of government debt and income taxes on consumption and saving in a world of infinitely lived house- holds having uncertain and heterogeneous incomes. The special structure of the model allows exact aggregation across households despite incomplete markets. The effects of government debt are shown to be substantial, roughly comparable to those resulting from finite horizons, and crucially dependent on the length of time until the debt is repaid. Also, anticipated changes in taxes are shown to cause anticipated changes in consumption. Finally, an index of fiscal stance is derived.Economic

Beating classical imaging limits with entangled photons

How can quantum mechanics deliver better imaging performance? Parametric down-conversion sources produce pairs of photons that are correlated in many degrees of freedom, including their spatial positions. By using a camera to detect these pairs of photons it is possible configure imaging systems that can either beat the classical resolution limit or the classical noise limit. We demonstrate how a simple down-conversion source based on a laser and non-linear crystal can be combined with an EMCCD camera to achieve either of these outcomes. Firstly, when both photons pass through the sample, we show a full-field, resolution-enhancing scheme, based on the centroid estimation of the photon pairs. By optimising the software control of the EMCCD camera running in the photon-sparse regime we achieve a resolution enhancement over the equivalent classical limit. Secondly, we show a similar scheme but where only one of the two photons pass through the sample and the other acts as a reference, in this case the ratio of the two resulting images eliminates the background noise of the camera, and background light, achieving an increase in image contrast

Resolution limits of quantum ghost imaging

Quantum ghost imaging uses photon pairs produced from parametric downconversion to enable an alternative method of image acquisition. Information from either one of the photons does not yield an image, but an image can be obtained by harnessing the correlations between them. Here we present an examination of the resolution limits of such ghost imaging systems. In both conventional imaging and quantum ghost imaging the resolution of the image is limited by the point-spread function of the optics associated with the spatially resolving detector. However, whereas in conventional imaging systems the resolution is limited only by this point spread function, in ghost imaging we show that the resolution can be further degraded by reducing the strength of the spatial correlations inherent in the downconversion process