735 research outputs found

    Velocity field near the jet orifice of a round jet in a crossflow

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    Experimentally determined velocities at selected locations near the jet orifice are presented and analyzed for a round jet in crossflow. Jet-to-crossflow velocity ratios of four and eight were studied experimentally for a round subsonic jet of air exhausting perpendicularly through a flat plate into a subsonic crosswind of the same temperature. Velocity measurements were made in cross sections to the jet plume located from one to four jet diameters from the orifice. Jet centerline and vortex properties are presented and utilized to extend the results of a previous study into the region close to the jet orifice

    Bayesian wavelength selection in multicomponent analysis

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    Trends and correlates of substance use disorders among probationers and parolees in the United States 2002–2014

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    BACKGROUND: Substance use and crime/recidivism are irrevocably linked. We explore the nuances of this association by highlighting the prevalence, trends, and correlates of substance use dsorders in a large group of probationers/parolees. METHODS: We examined SUDs among probationers and parolees in the United States using data from the National Study on Drug Use and Health (NSDUH). Logistic regression models were computed to examine eight distinct outcomes: alcohol abuse, illicit drug abuse, marijuana/hashish abuse, comorbid alcohol and illicit drug abuse, alcohol dependence, illicit drug dependence, marijuana/hashish dependence, and comorbid alcohol and illicit drug dependence. RESULTS: Probationers/parolees have high prevalence rates across all SUDs categories and these trends have been relatively constant. Prevalence rates for alcohol abuse and dependence are two to six times higher than for marijuana and other illicit drug abuse and dependence. Key correlates of substance abuse for probationers/parolees include: age, gender, race/ethnicity, education, income, risk propensity, crime/violence measures, and comorbid substance abuse. Similar correlates were found for substance dependence, in addition to employment and mental health treatment. CONCLUSIONS: This study indicates that SUDs are higher among probationer/parolees as compared to their non-supervised counterparts − between four and nine times higher − and these levels have changed little in recent years. Effectively responding to SUDs in this population may enhance adherence to supervision requirements, prevent recidivism, and improve public safety. We may be better served using limited funds for further development of evidence-based policies and programs, such as drug courts, which demonstrate reductions in both drug use and recidivism

    Analytical robustness of quantitative NIR chemical imaging for Islamic paper characterization

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    Recently, spectral imaging techniques such as Multispectral (MSI) and Hyperspectral Imaging (HSI) have gained importance in the field of heritage conservation. This paper explores the analytical robustness of quantitative chemical imaging for Islamic paper characterization by focusing on the effect of different measurement and processing parameters, i.e. acquisition conditions and calibration on the accuracy of the collected spectral data. This will provide a better understanding of the technique that can provide a measure of change in collections through imaging. For the quantitative model, special calibration target was devised using 105 samples from a well-characterized reference Islamic paper collection. Two material properties were of interest: starch sizing and cellulose degree of polymerization (DP). Multivariate data analysis methods were used to develop discrimination and regression models which were used as an evaluation methodology for the metrology of quantitative NIR chemical imaging. Spectral data were collected using a pushbroom HSI scanner (Gilden Photonics Ltd) in the 1000-2500 nm range with a spectral resolution of 6.3 nm using a mirror scanning setup and halogen illumination. Data were acquired at different measurement conditions and acquisition parameters. Preliminary results showed the potential of the evaluation methodology to show that measurement parameters such as the use of different lenses and different scanning backgrounds may not have a great influence on the quantitative results. Moreover, the evaluation methodology allowed for the selection of the best pre-treatment method to be applied to the data. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

    Two-photon coincident-frequency-entanglement via extended phase matching

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    We demonstrate a new class of frequency-entangled states generated via spontaneous parametric down-conversion under extended phase matching conditions. Biphoton entanglement with coincident signal and idler frequencies is observed over a broad bandwidth in periodically poled KTiOPO4_4. We demonstrate high visibility in Hong-Ou-Mandel interferometric measurements under pulsed pumping without spectral filtering, which indicates excellent frequency indistinguishability between the down-converted photons. The coincident-frequency entanglement source is useful for quantum information processing and quantum measurement applications.Comment: 4 pages, 3 figures, submitted to PR

    Quantitative chemical near-infrared hyperspectral imaging of Islamic paper

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    Heritage objects are well known for their compositional inhomogeneity due to materials and processes used in their production. Hyperspectral imaging is gaining importance in the field of heritage conservation by expanding spectroscopy to the examination of an entire surface of an object. This paper focuses on the application of near-infrared hyperspectral imaging to the characterisation of Islamic paper using a pushbroom HSI scanner in the 1000–2500 nm range to collect hyperspectral datacubes. A calibration target was devised using 105 samples from the well-characterised reference Islamic paper collection of the UCL Institute for Sustainable Heritage. Two material properties of Islamic paper were of interest: starch sizing and degree of polymerisation (DP). In addition to the developed discrimination and regression models using multivariate data analysis methods, a quantitative chemical map of the DP of an Islamic paper was generated as a case study for improved visualisation of the inhomogeneity of material properties, of value to researchers and conservators. As a case study, this research shows the wealth of valuable chemical information that near-infrared hyperspectral imaging could provide for diverse heritage applications in the future

    The UK Research Assessment Exercise (RAE 2008) and retail research output

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    The 2008 Research Assessment Exercise (RAE) in the United Kingdom provides a further opportunity to consider changing trends and patters in retail research, following on a previous commentary (Dawson et al. 2004). This comparison with shows that pressures continue to mount and are impacting retail knowledge creation and dissemination practices, not least in terms of those engaged in retail research, the topics and approaches utilised, the publication tactics and strategies and thus the standing of retail research in the UK and its reputation internationall

    An Open-Source Iterative Python Module for the Automated Identification of Photopeaks in Photon Spectra

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    The UK, and other countries worldwide, have benefited from nuclear energy to provide a low-carbon power source to fuel their increasing populations and industrial growth. In support of the extensive end-of-life decommissioning activities ongoing globally, as well as to enable accident clean-up and nuclear security/monitoring provisions; systems are necessary to rapidly and accurately detect and attribute the nature of any nuclear and/or radioactive materials. To facilitate the utilisation of the increasing suite of miniaturised radiation sensor systems for a range of largely robotic (whether aerial, underwater or ground-based) deployment applications, without the issue of being ’tethered’ to a specific vendor or system, an open-source and compact python module has been developed. Within this readily integrable code-base designed for incorporation into wider software architectures (such as the Robotic Operating System, or ROS), gamma-ray spectroscopy data are recorded in real-time and processed with a peak identification procedure once sufficient data has been recorded. Iterative peak-fitting is applied to determine the isotopic compositions of the incident radiation. The stand-alone application comprises two connected components: a small detector-specific module (or wrapper) that translates a detector’s serial output into the desired format, ahead of the main analysis function. Second, a photopeak identification is performed through an algorithm which uses the second derivative of the spectrum. The peaks identified are subsequently labelled by the program, utilizing the properties of all the mathematically detected/derived peaks, and finally output in a user-defined format for subsequent usage

    Development and initial testing of the person-centred health care for older adults survey.

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    Background: Health services are encouraged to adopt a strong person-centered approach to the provision of care and services for older people. The aim of this project was to establish a user-friendly, psychometrically valid, and reliable measure of healthcare staff’s practice, attitudes, and beliefs regarding person-centered healthcare. Methods: Item reduction (factor analysis) of a previously developed “benchmarking person-centred care” survey, followed by psychometric evaluations of the internal consistency reliability and construct validity, was conducted. The initial survey was completed by 1,428 healthcare staff from 17 health services across Victoria, Australia. Results: After removing 17 items from the previously developed “benchmarking person-centred care” survey, the revised 31-item survey (Person-Centred Health Care for Older Adults Survey) attained eight factors that explain 62.7% of the total variance with a Cronbach’s α coefficient of 0.91, indicating excellent internal consistency. Expert consultation confirmed that the revised survey had content validity. Conclusions: The results indicated that the Person-Centred Health Care for Older Adults Survey is a user-friendly, psychometrically valid, and reliable measure of staff perceptions of person-centered healthcare for use in hospital settings
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