391 research outputs found
Some Inequalities for the Dispersion of a Random Variable whose PDF is Defined on a Finite Interval
Some inequalities for the dispersion of a random variable whose pdf is defined on a finite interval and applications are given
Medical Imaging Utilization Trends in Radiation Oncology over the Past Decade
Purpose/Objective(s): We quantify the increase in use of pre-treatment imaging and verification imaging in radiation oncology over the past decade. We also quantify the trend towards hypofractionation, which has partially led to increased imaging.
Materials/Methods: The pre-treatment and verification imaging data used are from a single, tertiary, university-affiliated cancer center. Pre-treatment imaging was defined as magnetic resonance imaging (MRI), positron emission tomography (PET) and four-dimensional computed tomography (4DCT). Verification imaging was defined as cone-beam computed tomography (CBCT). All treatment approved plans were included from 2012 to 2021. Data extraction was performed using custom scripts interfacing with the treatment planning system (TPS) and patient information system. All registered image-sets of planning CT images with either advanced pre-treatment advanced imaging or verification images in the TPS were included. Hypofractionation sub-analysis was performed according to plans above and below 4 Gy per fraction that received a combination of pre-treatment and verification imaging.
Results: Between 2012 and 2021, a total of 42,214 plans were included. In 2021, MRI, PET, and 4DCT pre-treatment imaging modalities were used for 14%, 5%, and 3% of patients, respectively, which was an increase from 5%, 2%, and 0%, in 2012. In 2021, 55% of patients received CBCT for verification imaging compared to only 2% of patients in 2012. In the sub-analysis, cohort receiving greater than or equal to 4 Gy per fraction from 2012 to 2021, the percent of patients receiving one of MRI or PET for pre-treatment imaging and CBCT guidance for verification imaging increased from 1% to 22%. For the cohort receiving less than 4 Gy per fraction, there was an increase from 2012 to 2021 of 0% to 14% of patients receiving at least one of MRI or PET pretreatment imaging and CBCT for verification imaging. Table 1: Annual use of advanced pre-treatment, verification imaging, hypofractionation, and associated combination imaging shown. Entries indicate the percent (%) of patients per year with the imaging modality used in their treatment.
Conclusion: An increase in the adoption of advanced medical imaging was observed in standard of care treatments over the past 10 years. Imaging utilization continues to increase as clinical trial evidence matures. Further analysis could focus on the gap between desired standard of care for patients and the current offerings as well as the increase in capital and human resource requirement for implementation of these advancements
Pearling and SKCS Analysis of Australian Barley for the Asian Food Market
Australian barley sold to the Asian food market (apart from malt) is mainly pearled for use either as a rice extender, in the production of miso paste or for the Japanese spirit, shochu. The shochu market is the most profitable of the Asian staple foods to Australian barley producers. Barley that meets shochu grade will suit the majority of Asian food market requirements. Pearling quality is of greatest importance to buyers of shochu quality barley. Measurements of pearling quality using a small-scale pearler are laborious and qualitative. The Single Kernel Characterisation System from Perten Instruments has been under investigation, to quantitatively measure barley uniformity and determine its usefulness in predicting pearling quality. Previously, we found that SKCS could be used to predict pearling yield, screenings less than 2.0mm and broken kernels (Washington et al., 2001). Since these findings were based on a two-year study only, Pearling and SKCS analysis was performed over four years to validate the use of SKCS as a predictor of pearling quality. The diverse climate and soil types unique to South Australia have enabled a thorough investigation of grain quality for the shochu market. South Australia and Western Australia currently export Schooner (SA) and Stirling (WA) to Japan for shochu. Each variety provides unique properties desirable to shochu manufacturers. However, there is a need to investigate the quality of other varieties and breeding lines in order to select grain that provides consistent uniformity over diverse environmental conditions. A calibration to predict hardness using Near Infrared (NIR) Spectroscopy was investigated as a useful rapid screening tool at the silo. In this paper we discuss the environmental conditions, varieties and breeding lines most suitable for production of premium shochu grade barley
DEVELOPING A METHODOLOGICAL FRAMEWORK FOR THE PARTICIPATORY MEASUREMENT OF SUSTAINABILITY
The measurement of sustainability can provide significant information in order to plan and implement environmental policies. Several methods have been proposed in the literature in order to select the appropriate indicators along with a variety of techniques for their measurement. These methods are often divided in two main categories: a) a top-down approach where the selection of sustainability indicators is often based on the decision of scientists and policy-makers and b) a bottom-up approach where local stakeholders influence the selection and the measurement of indicators. In this paper we propose a methodological framework which allows the selection of sustainability indicators based on scientific research but at the same time allows citizens to influence both the selection of indicators and their measurement. The benefits of the specific methodological framework are two: a) to incorporate in different stages of the measurement the opinions of local stakeholders, b) to assist in policy decision-making through the assessment of the current situation of sustainability
Performance and economic assessment of mechanically integrated parallel hybrid aircraft
In this study, a selection of environmental and economic considerations of mechanically integrated parallel hybrid (MIPH) electric propulsion systems for single-aisle civil transport aircraft are assessed. The environmental assessment focuses on the carbon dioxide and nitrogen oxide emissions with different power management strategies and levels of battery technology. In the economic study, the potential subsidies and tax incentives required to make these aircraft financially viable are determined. To capture the performance results, models of the propulsion systems and airframe were constructed using the Siemens Simcenter Amesim systems modelling software. The operating cost was then computed using adapted direct operating cost estimation methods. Battery replacement was incorporated by using a battery cycle aging model. The results showed that using a battery energy density of 300 Wh/kg will not provide any meaningful benefits. For 600 Wh/kg, fuel savings of up to 3% for missions below 650 nm could be obtained for a PMS where the electrical powertrain operates during takeoff, climb, and cruise. However, the NOx emissions were lowest for the takeoff and climb only PMS, implying a trade-off when selecting a PMS. Based on the cost results, it is determined that taxation on carbon emissions would have to increase at least 50-fold from its current levels for the most optimistic scenarios. Alternatively, considerable subsidies, representing large percentages of the purchase price of the aircraft, will be needed
The Impact of Implementing Hypofractionation Prescription Regimens and Modernizing Delivery Technique on Treatment Resources in Breast Radiotherapy
Purpose/Objective(s): To determine the change in treatment resources due to the implementation of hypofractionated prescription regimen.
Materials/Methods: All patients between January 1, 2012 and December 31, 2021 receiving curative intent breast radiotherapy at a tertiary cancer center were included. Plan and patient data were extracted from the patient database with the treatment planning system and direct database query. Treatment plan categorization was completed using data elements to include only curative intent. Treatment plans for seroma boost or supraclavicular irradiation were excluded to ensure this analysis did not double-count regional nodal irradiation contribution or confound boost with hypofractionation. Treatment delivery time is recorded in the database for each patient treatment delivered. Average patient treatment time per year was estimated by multiplying the average fractions each year by average time in the same year. The standard fractionation regimens (95% of patients) are 42.56 Gy in 16, 40 Gy in 16, 27 Gy in 5 (accelerated partial breast irradiation), and 26 Gy in 5 (FAST-Forward). In the analysis, implementation milestones are indicated for new prescription regimens and delivery technique changes including deep inspiration breath hold (DIBH) for left-sided patient treatments and daily verification imaging.
Results: A total of 6505 patients were included. Table 1 details the total number of patients per year, the average number of fractions treated per patient, and the average treatment time of each patient plan. The average total fractions per treatment decreased from 17.5 in 2012 to 10.9 in 2021. The average treatment delivery time increased from 12.9 minutes to 21.4 minutes.
Conclusion: In considering total treatment resources, the interplay between hypofractionation and modernization delivery techniques is complex. The impact of hypofractionation reduced the average number of fractions but total treatment resources are offset with the implementation of modern treatment delivery techniques. Hypofractionated prescription regimens reduce the time and travel commitment required of patients on an individual basis, contributing to person-centered care
A scalable hydrogen propulsion system for civil transport aircraft
The aim of this research was to explore the application of engineering systems evolvability analysis techniques in devising potential scalable hydrogen propulsion systems for future civil transport aircraft. Baseline and derivative aircraft concepts were generated for a medium-sized long-range aircraft, with the derivative options having different levels of hydrogen incorporated in a dual-fuel arrangement (with separate hydrogen and kerosene turbofans), as well as potential turboelectric propulsion with boundary layer ingestion. Commonality between each baseline-derivative pair was then estimated, which could be used to predict the derivative development cost savings that could potentially be obtained when working from a specific baseline. The performance and cost results enabled different future scenarios to be explored. It was shown that developing the future concepts based on an existing state-of-the aircraft as baseline can offer considerable cost savings, as opposed to designing a clean sheet version. The importance of the baseline configuration selection in reducing the development cost for the different hydrogen configurations was also highlighted
Magnetic Connectivity between Active Regions 10987, 10988, and 10989 by Means of Nonlinear Force-Free Field Extrapolation
Extrapolation codes for modelling the magnetic field in the corona in
cartesian geometry do not take the curvature of the Sun's surface into account
and can only be applied to relatively small areas, \textit{e.g.}, a single
active region. We apply a method for nonlinear force-free coronal magnetic
field modelling of photospheric vector magnetograms in spherical geometry which
allows us to study the connectivity between multi-active regions. We use vector
magnetograph data from the Synoptic Optical Long-term Investigations of the Sun
survey (SOLIS)/Vector Spectromagnetograph(VSM) to model the coronal magnetic
field, where we study three neighbouring magnetically connected active regions
(ARs: 10987, 10988, 10989) observed on 28, 29, and 30 March 2008, respectively.
We compare the magnetic field topologies and the magnetic energy densities and
study the connectivities between the active regions(ARs). We have studied the
time evolution of magnetic field over the period of three days and found no
major changes in topologies as there was no major eruption event. From this
study we have concluded that active regions are much more connected
magnetically than the electric current.Comment: Solar Physic
- …