348 research outputs found

    Use of the Langmuir probe to determine the electron density and temperature surrounding re-entry vehicles Final report

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    Shock tube tests of Langmuir probe for determining electron density and temperature surrounding reentry vehicl

    The relationship between violence and alcohol abuse : self perception of addicted adults

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    While it is widely accepted that there is a positive correlation between alcohol use/abuse and violence, there is little consensus in the literature about the strength and nature of this association. Thus the need for more complex multivariate and qualitative studies has been recognized. This qualitative study explored what could be learned from a sample of men and women who are members of Alcoholic Anonymous (AA) and selfidentify as having engaged in violence while under the influence. For the vast majority of participants in this study, their violence came first; however, they first received treatment for their alcohol use/abuse. For these participants, their story of how their violence began was inextricably linked with the violence they experienced in childhood; and the only discernable demographic trend was a childhood history of violence and/or alcohol use/abuse. In contrast, a history of downward mobility as measured by the parents\u27 education and occupation was the only discernable trend in participants where their alcohol use/abuse came first. This group also received treatment first for their use/abuse of alcohol and was only violent when abusing alcohol. Finally, the use of alcohol was associated with intense affect regulation that could work two ways: i.e., release the inhibition against violent behavior or suppress the urge to act violently. There is a need for future research to see if these trends are sustained

    Interferometric differentiation between resonant Coherent Anti-Stokes Raman Scattering and nonresonant four-wave-mixing processes

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    A major impediment of using Coherent Anti-Stokes Raman Scattering to identify biological molecules is that the illumination levels required to produce a measurable signal often also produce significant nonresonant background from the medium, especially from water, that is not specific to the resonance being investigated. We present a method of using nonlinear interferometry to measure the temporal shape of the anti-Stokes signal to differentiate which components are resonant and nonresonant. This method is easily adaptable to most existing pulsed CARS illumination methods and should allow for distinguishing resonant CARS when using higher energy pulses. By examining the differences between signals produced by acetone and water, we show that the resonant and nonresonant signals can be clearly differentiated.Comment: 8 pages, 4 figure

    The impact of a high‐definition multileaf collimator for spine SBRT

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    PurposeAdvanced radiotherapy delivery systems designed for high‐dose, high‐precision treatments often come equipped with high‐definition multi‐leaf collimators (HD‐MLC) aimed at more finely shaping radiation dose to the target. In this work, we study the effect of a high definition MLC on spine stereotactic body radiation therapy (SBRT) treatment plan quality and plan deliverability.Methods and MaterialsSeventeen spine SBRT cases were planned with VMAT using a standard definition MLC (M120), HD‐MLC, and HD‐MLC with an added objective to reduce monitor units (MU). M120 plans were converted into plans deliverable on an HD‐MLC using in‐house software. Plan quality and plan deliverability as measured by portal dosimetry were compared among the three types of plans.ResultsOnly minor differences were noted in plan quality between the M120 and HD‐MLC plans. Plans generated with the HD‐MLC tended to have better spinal cord sparing (3% reduction in maximum cord dose). HD‐MLC plans on average had 12% more MU and 55% greater modulation complexity as defined by an in‐house metric. HD‐MLC plans also had significantly degraded deliverability. Of the VMAT arcs measured, 94% had lower gamma passing metrics when using the HD‐MLC.ConclusionModest improvements in plan quality were noted when switching from M120 to HD‐MLC at the expense of significantly less accurate deliverability in some cases.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139989/1/acm212197.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139989/2/acm212197_am.pd

    Independent Control of Topography for 3D Patterning of the ECM Microenvironment

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    Biomimetic extracellular matrix (ECM) topographies driven by the magnetic-field-directed self-assembly of ECM protein-coated magnetic beads are fabricated. This novel bottom-up method allows us to program isotropic, anisotropic, and diverse hybrid ECM patterns without changing other physicochemical properties of the scaffold material. It is demonstrated that this 3D anisotropic matrix is able to guide the dendritic protrusion of cells.ope

    First- and second-order contributions to depth perception in anti-correlated random dot stereograms.

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    The binocular energy model of neural responses predicts that depth from binocular disparity might be perceived in the reversed direction when the contrast of dots presented to one eye is reversed. While reversed-depth has been found using anti-correlated random-dot stereograms (ACRDS) the findings are inconsistent across studies. The mixed findings may be accounted for by the presence of a gap between the target and surround, or as a result of overlap of dots around the vertical edges of the stimuli. To test this, we assessed whether (1) the gap size (0, 19.2 or 38.4 arc min) (2) the correlation of dots or (3) the border orientation (circular target, or horizontal or vertical edge) affected the perception of depth. Reversed-depth from ACRDS (circular no-gap condition) was seen by a minority of participants, but this effect reduced as the gap size increased. Depth was mostly perceived in the correct direction for ACRDS edge stimuli, with the effect increasing with the gap size. The inconsistency across conditions can be accounted for by the relative reliability of first- and second-order depth detection mechanisms, and the coarse spatial resolution of the latter
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