Production costs in the apple industry : comments on a survey

IN 1964 and 1965, light and heavy bearing years respectively, apples cost $2.40 per bushel to produce in Western Australia. This figure, to be considered with many other factors, was reached in a cost-of-production survey of 45 selected growers. Packing and labour costs, in that order, were the two biggest cost-of-production items

A Method to Determine the In-Air Spatial Spread of Clinical Electron Beams

We propose and analyze in detail a method to measure the in-air spatial spread parameter of clinical electron beams. Measurements are performed at the center of the beam and below the adjustable collimators sited in asymmetrical configuration in order to avoid the distortions due to the presence of the applicator. The main advantage of our procedure lies in the fact that the dose profiles are fitted by means of a function which includes, additionally to the Gaussian step usually considered, a background which takes care of the dose produced by different mechanisms that the Gaussian model does not account for. As a result, the spatial spread is obtained directly from the fitting procedure and the accuracy permits a good determination of the angular spread. The way the analysis is done is alternative to that followed by the usual methods based on the evaluation of the penumbra width. Besides, the spatial spread found shows the quadratic-cubic dependence with the distance to the source predicted by the Fermi-Eyges theory. However, the corresponding values obtained for the scattering power are differing from those quoted by ICRU nr. 35 by a factor ~2 or larger, what requires of a more detailed investigation.Comment: 11 pages, 5 Postscript figures, to be published in Medical Physic

Methods for Characterizing the Reliability of Deployable Modules for Large Optical Reflectors

The In-Space Telescope Assembly Robotics (ISTAR) project has proposed an architecture for a large robotically-assembled telescope in space, comprised of many deployable truss modules. The truss modules are based on the Pactruss deployment scheme and are equipped with Rolamite tape spring hinges. Fabrication and assembly errors that arise from bulk manufacturing the modules may make the deployment unreliable. A simulation toolkit has been developed to characterize the deployment behavior of the module in the presence of such errors. This paper first outlines the details of the toolkit, including the truss model, the Rolamite hinge model, and the simulation methodology. It then describes the experiment designed to validate the toolkit. A module was constructed and deployed while tracking the displacements of a select node and the rotations of the Rolamite hinges. The measured shape of this module was recreated in the simulation model and the same parameters were obtained. It was found that the experimental and simulated nodal displacements matched within 10%. The experimental hinge behavior was generally captured in the simulation, with some discrepancies in the latching of one hinge. The possible causes for the discrepancies and ongoing work to improve the results are discussed in the paper

Planning and delivery of intensity modulated bolus electron conformal therapy

PURPOSE: Bolus electron conformal therapy (BECT) is a clinically useful, well-documented, and available technology. The addition of intensity modulation (IM) to BECT reduces volumes of high dose and dose spread in the planning target volume (PTV). This paper demonstrates new techniques for a process that should be suitable for planning and delivering IM-BECT using passive radiotherapy intensity modulation for electrons (PRIME) devices. METHODS: The IM-BECT planning and delivery process is an addition to the BECT process that includes intensity modulator design, fabrication, and quality assurance. The intensity modulator (PRIME device) is a hexagonal matrix of small island blocks (tungsten pins of varying diameter) placed inside the patient beam-defining collimator (cutout). Its design process determines a desirable intensity-modulated electron beam during the planning process, then determines the island block configuration to deliver that intensity distribution (segmentation). The intensity modulator is fabricated and quality assurance performed at the factory (.decimal, LLC, Sanford, FL). Clinical quality assurance consists of measuring a fluence distribution in a plane perpendicular to the beam in a water or water-equivalent phantom. This IM-BECT process is described and demonstrated for two sites, postmastectomy chest wall and temple. Dose plans, intensity distributions, fabricated intensity modulators, and quality assurance results are presented. RESULTS: IM-BECT plans showed improved D CONCLUSION: These results demonstrated the feasibility of translating IM-BECT to the clinic using the techniques presented for treatment planning, intensity modulator design and fabrication, and quality assurance processes

A Neptune Orbiter Concept Using Drag Modulated Aerocaptue (DMA) and the Adaptable, Deployable Entry and Placement Technology (ADEPT)

Conceptual Neptune orbiter was designed for the purpose of assessing mission feasibilityBuilt off of the 2017 Pre-Decadal Study, but adapted for drag modulation aerocapture.Science payload includes: Narrow Angle camera, Doppler Imager, Magnetometer, Atmospheric Probe (w/ ASI, Nephelometer, Mass Spectrometer). Baseline concept of operations releases probe prior to orbit insertion, but investigations are ongoing to assess the feasibility of bringing the probe to orbit before release

Transverse spin dependence of pp total cross‐sections

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87331/2/72_1.pd

Tension of knotted surgical sutures shows tissue specific rapid loss in a rodent model

<p>Abstract</p> <p>Background</p> <p>Every surgical suture compresses the enclosed tissue with a tension that depends from the knotting force and the resistance of the tissue. The aim of this study was to identify the dynamic change of applied suture tension with regard to the tissue specific cutting reaction.</p> <p>Methods</p> <p>In rabbits we placed single polypropylene sutures (3/0) in skin, muscle, liver, stomach and small intestine. Six measurements for each single organ were determined by tension sensors for 60 minutes. We collected tissue specimens to analyse the connective tissue stability by measuring the collagen/protein content.</p> <p>Results</p> <p>We identified three phases in the process of suture loosening. The initial rapid loss of the first phase lasts only one minute. It can be regarded as cutting through damage of the tissue. The percentage of lost tension is closely related to the collagen content of the tissue (r = -0.424; p = 0.016). The second phase is characterized by a slower decrease of suture tension, reflecting a tissue specific plastic deformation. Phase 3 is characterized by a plateau representing the remaining structural stability of the tissue. The ratio of remaining tension to initial tension of phase 1 is closely related to the collagen content of the tissue (r = 0.392; p = 0.026).</p> <p>Conclusions</p> <p>Knotted non-elastic monofilament sutures rapidly loose tension. The initial phase of high tension may be narrowed by reduction of the surgeons' initial force of the sutures' elasticity to those of the tissue. Further studies have to confirm, whether reduced tissue compression and less local damage permits improved wound healing.</p

Adolescent brain maturation and cortical folding: evidence for reductions in gyrification

Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla) magnetic resonance imaging (MRI) data from 79 healthy subjects (34 males and 45 females) between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI). In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM) volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development

Can prophylactic breast irradiation contribute to cardiac toxicity in patients with prostate cancer receiving androgen suppressing drugs?

<p>Abstract</p> <p>Background</p> <p>Androgen suppression treatment (AST) might increase the risk of cardiac morbidity in prostate cancer patients. Possible explanations were provided, however, they disregard the potential contribution of prophylactic radiotherapy to the mamillary regions (PMRT, prescribed to avoid gynecomastia).</p> <p>Methods</p> <p>We studied the exposure of the heart in a typical electron beam PMRT setting by evaluating computed tomography (CT) scans in 40 non-cancer patients (age 65 and 75 years in 50% each) and 17 prostate cancer patients. Five of the younger, 7 of the older and 4 of the cancer patients had significant cardiac disease.</p> <p>Results</p> <p>The median distance between skin and outer heart contour decreased with age. In all three groups, patients with cardiac morbidity had smaller distances. When using the CT-determined PMRT beam energy, 10% of the younger, 15% of the older and none of the prostate cancer patients would receive approximately 50% of the prescription dose to a part of the heart (2 had no history of cardiac disease). When using the clinically rather than CT-determined beam energy, as often done in daily practice, an additional 12.5% of the non-cancer and 12% of the prostate cancer patients would be exposed to comparably high doses.</p> <p>Conclusion</p> <p>The present data provide preliminary evidence that PMRT might be a factor that contributes to cardiac side effects. Previous studies that established a relationship between AST and cardiac morbidity did not include information on delivery of PMRT.</p

Determining Vitamin D Status: A Comparison between Commercially Available Assays

Background: Vitamin D is not only important for bone health but can also affect the development of several non-bone diseases. The definition of vitamin D insufficiency by serum levels of 25-hydroxyvitamin D depends on the clinical outcome but might also be a consequence of analytical methods used for the definition. Although numerous 25-hydroxyvitamin D assays are available, their comparability is uncertain. We therefore aim to investigate the precision, accuracy and clinical consequences of differences in performance between three common commercially available assays. Methodology/Principal Findings: Serum 25-hydroxyvitamin D levels from 204 twins from the Swedish Twin Registry were determined with high-pressure liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLCAPCI-MS), a radioimmunoassay (RIA) and a chemiluminescent immunoassay (CLIA). High inter-assay disagreement was found. Mean 25-hydroxyvitamin D levels were highest for the HPLC-APCI-MS technique (85 nmol/L, 95% CI 81-89), intermediate for RIA (70 nmol/L, 95% CI 66-74) and lowest with CLIA (60 nmol/L, 95% CI 56-64). Using a 50-nmol/L cut-off, 8% of the subjects were insufficient using HPLC-APCI-MS, 22% with RIA and 43% by CLIA. Because of the heritable component of 25-hydroxyvitamin D status, the accuracy of each method could indirectly be assessed by comparison of within-twin pair correlations. The strongest correlation was found for HPLC-APCI-MS (r = 0.7), intermediate for RIA (r = 0.5) and lowest for CLIA (r = 0.4). Regression analyses between the methods revealed a non-uniform variance (p&lt;0.0001) depending on level of 25-hydroxyvitamin D. Conclusions/Significance: There are substantial inter-assay differences in performance. The most valid method was HPLCAPCI-MS. Calibration between 25-hydroxyvitamin D assays is intricate