90 research outputs found

    Development of a neutron diffraction system and neutron imaging system for beamport characterization

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    Master of ScienceDepartment of Mechanical and Nuclear EngineeringDouglas S. McGregorSemiconductor neutron detector design, fabrication and testing are all performed at Kansas State University (KSU). The most prevalent neutron detectors built by the KSU Semiconductor Materials And Radiological Technologies Laboratory (SMART Lab) are comprised of silicon diodes with [superscript]6LiF as a neutron converter material. Neutron response testing and calibration of the detectors is performed in a neutron detector test facility. The facility utilizes diffraction with a pyrolytic graphite (PG) monochromator to produce a diffracted neutron beam at the northwest beamport of the KSU Training Research Isotope production General Atomics (TRIGA) Mark-II nuclear reactor. A 2-D neutron beam monitor can also be used in conjunction with the test facility for active calibrations. Described in the following work are the design, construction and operation of a neutron detector test facility and a 2-D neutron detection array. The diffracted neutron beam at the detector test facility has been characterized to yield a neutron beam with an average Gaussian energy of 0.0253 eV. The diffracted beam yields a flux of 1.2x10[superscript]4 neutrons/cm[superscript]2/s at 100 kW of reactor power. The PG monochromator is diffracting on the (002) plane that has been positioned at a Bragg angle of 15.5 degrees. The 2-D neutron detection array has been characterized for uniform pixel response and uniform neutron detection efficiency. The 2-D 5x5 array of neutron detectors with a neutron detection efficiency of approximately 0.5 percent has been used as a beam monitor when performing detector testing. The amplifier circuits for the 5x5 array were designed at the KSU Electronics Design Lab (EDL) and were coupled to a LabVIEW field-programmable gate array that is read out by a custom LabVIEW virtual instrument. The virtual instrument has been calibrated to produce a pixel response that varies by less than two percent from pixel to pixel. The array has been used for imaging and active monitoring of the diffracted neutron beam at the detector test facility. The following work is part of on-going research to develop various types of solid state semiconductor neutron detectors

    The Data Imaginary: Fears and Fantasies

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    The Data Imaginary: Fears and Fantasies brings together eminent and emerging artists and designers to show how creative applications of data technology are crucial for a vital, inclusive and sustainable future. The exhibition includes artworks and designs that engage audiences in critical, playful and agentic reflections on data and creative technologies. Through the exhibition, workshops, podcast and publication, the audience will be empowered to respond to climate change patterns and future city design, interact with empathy from remote locations, learn about Indigenous cultural knowledges and reflect on everyday habits that secure data privacy. Dedicated url: http://thedataimaginary.com

    Curating the Data Imaginary: Fears and Fantasies in the Middle of a Dataverse Takeover (Like Science Fiction but Weirder)

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    As we catapulted by COVID-19 to an increasingly abstract datascape, the curatorium of Katherine Moline, Angela Goddard, Blaklash (Amanda Hayman and Troy Casey) and Beck Davis developed the exhibition The Data Imaginary: Fears and Fantasies at Griffith University Art Museum, Brisbane for 2021. Our original aim—to explore data experiments in relation to climate change, data security and urban landscapes, many informed and shaped by Indigenous knowledges—had become our reality with the global pandemic. The challenge to the norms and standards of the social imaginary—how data operates and for whom it is operationalised—made by artists, designers and scientists have become a platform for survival – outside of the gallery and in our everyday worlds. The public fears and fantasises regarding data analysis throughout the pandemic now guide our curatorial framework. This chapters explore how the curators and exhibition participants have reformulated The Data Imaginary exhibition for pandemic life in a dark Eden and how we are reviewing the selection of works so that for example, Lola Greeno’s embodied knowledge of how climate change is impacting the materiality of Palawa shell stringing on the shores of the cool waters surrounding Lutruwita (Tasmania), contrasts with Silvio Carta’s dystopian vision of human value in The Machine’s Eye - How machines see our world

    Lifetime body size and reproductive factors: comparisons of data recorded prospectively with self reports in middle age

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    <p>Abstract</p> <p>Background</p> <p>Data on lifetime exposures are often self-reported in epidemiologic studies, sometimes many years after the relevant age. Validity of self-reported data is usually inferred from their agreement with measured values, but few studies directly quantify the likely effects of reporting errors in body size and reproductive history variables on estimates of disease-exposure associations.</p> <p>Methods</p> <p>The MRC National Survey of Health and Development (NSHD) and the Million Women Study (MWS) are UK population-based prospective cohorts. The NSHD recruited participants at birth in 1946 and has followed them at regular intervals since then, whereas the MWS recruited women in middle age. For 541 women who were participants in both studies, we used statistical measures of association and agreement to compare self-reported MWS data on body size throughout life and reproductive history, obtained in middle age, to NSHD data measured or reported close to the relevant ages. Likely attenuation of estimates of linear disease-exposure associations due to the combined effects of random and systematic errors was quantified using regression dilution ratios (RDRs).</p> <p>Results</p> <p>Data from the two studies were very strongly correlated for current height, weight and body mass index, and age at menopause (Pearson r = 0.91-0.95), strongly correlated for birth weight, parental heights, current waist and hip circumferences and waist-to-height ratio (r = 0.67-0.80), and moderately correlated for age at menarche and waist-to-hip ratio (r = 0.52-0.57). Self-reported categorical body size and clothes size data for various ages were moderately to strongly associated with anthropometry collected at the relevant times (Spearman correlations 0.51-0.79). Overall agreement between the studies was also good for most quantitative variables, although all exhibited both random and systematic reporting error. RDRs ranged from 0.66 to 0.86 for most variables (slight to moderate attenuation), except weight and body mass index (1.02 and 1.04, respectively; little or no attenuation), and age at menarche, birth weight and waist-to-hip ratio (0.44, 0.59 and 0.50, respectively; substantial attenuation).</p> <p>Conclusions</p> <p>This study provides some evidence that self-reported data on certain anthropometric and reproductive factors may be adequate for describing disease-exposure associations in large epidemiological studies, provided that the effects of reporting errors are quantified and the results are interpreted with caution.</p

    Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes

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    BACKGROUND: Carriers of germline mutations in DNA mismatch repair (MMR) genes have a high risk of colorectal cancer (CRC), but the modifiers of this risk are not well established. We estimated an association between body mass index (BMI) in early adulthood and subsequent risk of CRC for carriers and, as a comparison, estimated the association for non-carriers. METHODS: A weighted Cox regression was used to analyse height and weight at 20 years reported by 1324 carriers of MMR gene mutations (500 MLH1, 648 MSH2, 117 MSH6 and 59 PMS2) and 1219 non-carriers from the Colon Cancer Family Registry. RESULTS: During 122,304 person-years of observation, we observed diagnoses of CRC for 659 carriers (50%) and 36 non-carriers (3%). For carriers, the risk of CRC increased by 30% for each 5 kg m(-2) increment in BMI in early adulthood (hazard ratio, HR: 1.30; 95% confidence interval, CI: 1.08-1.58; P=0.01), and increased by 64% for non-carriers (HR: 1.64; 95% CI: 1.02-2.64; P=0.04) after adjusting for sex, country, cigarette smoking and alcohol drinking (and the MMR gene that was mutated in carriers). The difference in HRs for carriers and non-carriers was not statistically significant (P=0.50). For MLH1 and PMS2 (MutLα heterodimer) mutation carriers combined, the corresponding increase was 36% (HR: 1.36; 95% CI: 1.05-1.76; P=0.02). For MSH2 and MSH6 (MutSα heterodimer) mutation carriers combined, the HR was 1.26 (95% CI: 0.96-1.65; P=0.09). There was no significant difference between the HRs for MutLα and MutSα heterodimer carriers (P=0.56). CONCLUSION: Body mass index in early adulthood is positively associated with risk of CRC for MMR gene mutation carriers and non-carriers

    Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes

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    BACKGROUND: Carriers of germline mutations in DNA mismatch repair (MMR) genes have a high risk of colorectal cancer (CRC), but the modifiers of this risk are not well established. We estimated an association between body mass index (BMI) in early adulthood and subsequent risk of CRC for carriers and, as a comparison, estimated the association for non-carriers. METHODS: A weighted Cox regression was used to analyse height and weight at 20 years reported by 1324 carriers of MMR gene mutations (500 MLH1, 648 MSH2, 117 MSH6 and 59 PMS2) and 1219 non-carriers from the Colon Cancer Family Registry. RESULTS: During 122,304 person-years of observation, we observed diagnoses of CRC for 659 carriers (50%) and 36 non-carriers (3%). For carriers, the risk of CRC increased by 30% for each 5 kg m(-2) increment in BMI in early adulthood (hazard ratio, HR: 1.30; 95% confidence interval, CI: 1.08-1.58; P=0.01), and increased by 64% for non-carriers (HR: 1.64; 95% CI: 1.02-2.64; P=0.04) after adjusting for sex, country, cigarette smoking and alcohol drinking (and the MMR gene that was mutated in carriers). The difference in HRs for carriers and non-carriers was not statistically significant (P=0.50). For MLH1 and PMS2 (MutLα heterodimer) mutation carriers combined, the corresponding increase was 36% (HR: 1.36; 95% CI: 1.05-1.76; P=0.02). For MSH2 and MSH6 (MutSα heterodimer) mutation carriers combined, the HR was 1.26 (95% CI: 0.96-1.65; P=0.09). There was no significant difference between the HRs for MutLα and MutSα heterodimer carriers (P=0.56). CONCLUSION: Body mass index in early adulthood is positively associated with risk of CRC for MMR gene mutation carriers and non-carriers
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