265 research outputs found

    Evaluation of Few-View Reconstruction Parameters for Illicit Substance Detection using Fast-Neutron Transmission Spectroscopy

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    We have evaluated the performance of an illicit substance detection system that performs image reconstruction using the Maximum Likelihood algebraic reconstruction algorithm, a few number of projections, and relatively coarse projection and pixel resolution. This evaluation was done using receiver operator curves and simulated data from the fast-neutron transmission spectroscopy system operated in a mode to detect explosives in luggage. The results show that increasing the number of projection angles is more important than increasing the projection resolution, the reconstructed pixel resolution, or the number of iterations in the Maximum Likelihood algorithm. A 100% detection efficiency with essentially no false positives is possible for a square block of RDX explosive, a projection resolution of 2 cm, a reconstructed pixel size of 2x2 cm, and five projection angles. For rectangular shaped explosives more angles are required to obtain the same system performance

    Characterization of Artifacts Introduced by the Empirical Volcano-Scan Atmospheric Correction Commonly Applied to CRISM and OMEGA Near-Infrared Spectra

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    The empirical volcano-scan atmospheric correction is widely applied to Martian near infrared CRISM and OMEGA spectra between 1000 and 2600 nanometers to remove prominent atmospheric gas absorptions with minimal computational investment. This correction method employs division by a scaled empirically-derived atmospheric transmission spectrum that is generated from observations of the Martian surface in which different path lengths through the atmosphere were measured and transmission calculated using the Beer-Lambert Law. Identifying and characterizing both artifacts and residual atmospheric features left by the volcano-scan correction is important for robust interpretation of CRISM and OMEGA volcano scan corrected spectra. In order to identify and determine the cause of spectral artifacts introduced by the volcano-scan correction, we simulated this correction using a multiple scattering radiative transfer algorithm (DISORT). Simulated transmission spectra that are similar to actual CRISM- and OMEGA-derived transmission spectra were generated from modeled Olympus Mons base and summit spectra. Results from the simulations were used to investigate the validity of assumptions inherent in the volcano-scan correction and to identify artifacts introduced by this method of atmospheric correction. We found that the most prominent artifact, a bowl-shaped feature centered near 2000 nanometers, is caused by the inaccurate assumption that absorption coefficients of CO2 in the Martian atmosphere are independent of column density. In addition, spectral albedo and slope are modified by atmospheric aerosols. Residual atmospheric contributions that are caused by variable amounts of dust aerosols, ice aerosols, and water vapor are characterized by the analysis of CRISM volcano-scan corrected spectra from the same location acquired at different times under variable atmospheric conditions

    Dimensions of Liberal Education at Brockport

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    Editor: H. Larry Humm (College at Brockport emeritus). Editorial board: Robert W. Strayer (professor emeritus, College at Brockport) ; W. Bruce Leslie, (College at Brockport faculty member) ; Robert S. Getz (professor emeritus, College at Brockport) ; J. Douglas Hickerson (former Director of Student Affairs, College at Brockport), Kenneth L. Jones (former College at Brockport faculty member) ; Charles R. Edwards (professor emeritus, College at Brockport). Also includes chapters by the following emeriti and former faculty members and professionals of The College at Brockport: Donald S. Douglas (former provost), Harold L. Rakov (emeritus), Roger M. Weir (emeritus), Owen S. Ireland (current), Edward J. Gucker (emeritus), Warren Fraleigh (emeritus), Lynn H. Parsons (emeritus), Ian H. Henderson (emeritus), Robert J. Gemmett (emeritus), J. Emory Morris (emeritus), Beth E. VanFossen (former faculty member), Peter L. Marchant (emeritus), Gladdys W. Church (former Director of the Learning Skills Center). An instructional development project of the Educational Communications Center, State University College at Brockport, Brockport, New York. Contents: On coming to college for the first time : Great expectations, yours and ours / Donald S. Douglas -- High school and college, what’s the difference? / Harold L. Rakov -- Living in a college community / Roger M. Weir -- A liberal arts education: what, why and how: The liberating arts and personal freedom / J. Douglas Hickerson -- The liberal arts, preparation for a career / Roger M. Weir -- Liberally educated people, knowing them when you see them: Perspective 1, Gaining knowledge, discipline, and values / Owen S. Ireland -- Perspective 2, Nurturing curiosity, creativity, and commitment / Edward J. Gucker -- Perspective 3, Cultivating freedom / Warren Fraleigh -- Democracy and the liberal arts, Is there a connection? / Lynn H. Parsons -- From Socrates to Brockport, your place in a long tradition / W. Bruce Leslie -- Why study the fine arts? / Ian H. Henderson -- Why study the humanities? / Robert J. Gemmett -- Why study the sciences? / J. Emory Morris -- Why study the social sciences? / Beth E. VanFossen -- More than making it: getting the most out of college : Where am I going? How do I get there? Some thoughts on academic planning / Robert S. Getz -- Thinking about thinking / H. Larry Humm -- How not to be a victim of time, a first letter to an anxious student / Peter L. Marchant -- Reading in college, more than turning pages / Charles R. Edwards -- Going to class-- being there is not enough / H. Larry Humm -- How not to be a victim of essay assignments, a second letter to an anxious student / Peter L. Marchant -- Making the most of tests / Gladdys W. Church.https://digitalcommons.brockport.edu/bookshelf/1328/thumbnail.jp

    Surgical experience and identification of errors in laparoscopic cholecystectomy

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    BACKGROUND: Surgical errors are acts or omissions resulting in negative consequences and/or increased operating time. This study describes surgeon-reported errors in laparoscopic cholecystectomy. METHODS: Intraoperative videos were uploaded and annotated on Touch SurgeryTM Enterprise. Participants evaluated videos for severity using a 10-point intraoperative cholecystitis grading score, and errors using Observational Clinical Human Reliability Assessment, which includes skill, consequence, and mechanism classifications. RESULTS: Nine videos were assessed by 8 participants (3 junior (specialist trainee (ST) 3-5), 2 senior trainees (ST6-8), and 3 consultants). Participants identified 550 errors. Positive relationships were seen between total operating time and error count (r2 = 0.284, P < 0.001), intraoperative grade score and error count (r2 = 0.578, P = 0.001), and intraoperative grade score and total operating time (r2 = 0.157, P < 0.001). Error counts differed significantly across intraoperative phases (H(6) = 47.06, P < 0.001), most frequently at dissection of the hepatocystic triangle (total 282; median 33.5 (i.q.r. 23.5-47.8, range 15-63)), ligation/division of cystic structures (total 124; median 13.5 (i.q.r. 12-19.3, range 10-26)), and gallbladder dissection (total 117; median 14.5 (i.q.r. 10.3-18.8, range 6-26)). There were no significant differences in error counts between juniors, seniors, and consultants (H(2) = 0.03, P = 0.987). Errors were classified differently. For dissection of the hepatocystic triangle, thermal injuries (50 in total) were frequently classified as executional, consequential errors; trainees classified thermal injuries as step done with excessive force, speed, depth, distance, time or rotation (29 out of 50), whereas consultants classified them as incorrect orientation (6 out of 50). For ligation/division of cystic structures, inappropriate clipping (60 errors in total), procedural errors were reported by junior trainees (6 out of 60), but not consultants. For gallbladder dissection, inappropriate dissection (20 errors in total) was reported in incorrect planes by consultants and seniors (6 out of 20), but not by juniors. Poor economy of movement (11 errors in total) was reported more by consultants (8 out of 11) than trainees (3 out of 11). CONCLUSION: This study suggests that surgical experience influences error interpretation, but the benefits for surgical training are currently unclear

    Extensive MRO CRISM Observations of 1.27 micron O2 Airglow in Mars Polar Night and Their Comparison to MRO MCS Temperature Profiles and LMD GCM Simulations

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    The Martian polar night distribution of 1.27 micron (0-0) band emission from O2 singlet delta [O2(1Delta(sub g))] is determined from an extensive set of Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectral Mapping (CRISM) limb scans observed over a wide range of Mars seasons, high latitudes, local times, and longitudes between 2009 and 2011. This polar nightglow reflects meridional transport and winter polar descent of atomic oxygen produced from CO2 photodissociation. A distinct peak in 1.27 micron nightglow appears prominently over 70-90NS latitudes at 40-60 km altitudes, as retrieved for over 100 vertical profiles of O2(1Delta(sub g)) 1.27 micron volume emission rates (VER). We also present the first detection of much (x80+/-20) weaker 1.58 micron (0-1) band emission from Mars O2(1Delta(sub g)). Co-located polar night CRISM O2(1Delta(sub g)) and Mars Climate Sounder (MCS) (McCleese et al., 2008) temperature profiles are compared to the same profiles as simulated by the Laboratoire de Mtorologie Dynamique (LMD) general circulation/photochemical model (e.g., Lefvre et al., 2004). Both standard and interactive aerosol LMD simulations (Madeleine et al., 2011a) underproduce CRISM O2(1Delta(sub g)) total emission rates by 40%, due to inadequate transport of atomic oxygen to the winter polar emission regions. Incorporation of interactive cloud radiative forcing on the global circulation leads to distinct but insufficient improvements in modeled polar O2(1Delta(sub g)) and temperatures. The observed and modeled anti-correlations between temperatures and 1.27 mm band VER reflect the temperature dependence of the rate coefficient for O2(1Delta(sub g)) formation, as provided in Roble (1995)
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