A unified mixed-integer programming model for simultaneous fluence weight and aperture optimization in VMAT, tomotherapy, and cyberknife

All rights reserved. In this paper, we propose and study a unified mixed-integer programming model that simultaneously optimizes fluence weights and multi-leaf collimator (MLC) apertures in the treatment planning optimization of VMAT, Tomotherapy, and CyberKnife. The contribution of our model is threefold: (i) Our model optimizes the fluence and MLC apertures simultaneously for a given set of control points. (ii) Our model can incorporate all volume limits or dose upper bounds for organs at risk (OAR) and dose lower bound limits for planning target volumes (PTV) as hard constraints, but it can also relax either of these constraint sets in a Lagrangian fashion and keep the other set as hard constraints. (iii) For faster solutions, we propose several heuristic methods based on the MIP model, as well as a meta-heuristic approach. The meta-heuristic is very efficient in practice, being able to generate dose- and machinery-feasible solutions for problem instances of clinical scale, e.g., obtaining feasible treatment plans to cases with 180 control points, 6750 sample voxels and 18,000 beamlets in 470 seconds, or cases with 72 control points, 8000 sample voxels and 28,800 beamlets in 352 seconds. With discretization and down-sampling of voxels, our method is capable of tackling a treatment field of 8000-64,000cm3, depending on the ratio of critical structure versus unspecified tissues.

Effect of storage on the biochemical and processing quality of Adzuki Bean (Vigna angularis)

Storage of adzuki beans and other pulse grains causes biochemical and physical changes that affect the hydration properties of the beans. This affects the quality of products made from the beans such as the Japanese bean paste “ann.” Storage, particularly under unfavourable conditions, leads to the “hard shell” phenomenon, where beans fail to imbibe water when soaked and remain hard, and the “hard-to-cook” phenomenon where the seeds hydrate normally, but the cotyledon fails to hydrate and soften during cooking. The hard shell phenomenon is attributable to impermeability of the seed coat to water, which is due to biochemical changes in the seed coat, such as the formation of protein-tannin complexes, and biophysical changes such as reduction in size or closure of the straphiole aperture in the hilum area—the main area for water entry into the adzuki bean. The hard-to-cook phenomenon is due to changes in the cotyledon tissue, which include formation of insoluble pectinates, lignification of the cell wall and middle lamella, interaction of condensed tannins with proteins and starch, and changes to the structure and functionality of the cellular proteins and starch.

Investigating social marketing, benchmarking and public policy development in environmental management

This paper discusses, an application of social marketing relating to pro-environmental awareness and social change. The integration of consumer behaviour theory into social marketing has been highlighted in the literature as requiring greater attention. Social marketing campaigns, like all marketing activities, rely on an understanding of stakeholders' attitudes and motivations in regard to the issue of concern, as well as towards the desired modified behaviour or lack of behaviour. The study highlights the marketing paradigms of benchmarking and social marketing in a not for profit governmental environment. Serrated Tussock has been designated as a weed of national significance and therefore the program has national implications (Thorp 2000). Even though issues associated with introduced species are less publicised than other environmental issues on the world stage, the associated environmental problems are no less severe than those caused by production and consumption activities. Weed control is a widespread problem facing individuals, communities and governments at all levels. A triangulatory approach, involving three distinct phases and incorporating both qualitative and quantitative tools, was used for the research design. The qualitative phase involved focus groups and in depth interviews with landholders, focus groups with professionals in the field and a focus group of key stakeholders. The mail survey resulted in a representative sample of 608 usable responses from the infestation area. The research conducted in this study illustrates how the various stages in the social marketing process were achieved and recommendations consistent with social marketing theory were generated.

Investigation of the intersection of constraints model of motion perception

The direction and speed of motion of a one-dimensional (1-D) stimulus, such as a grating, presented within a circular aperture is ambiguous. This ambiguity, referred to as the Aperture Problem (Fennema & Thompson, 1979) results from (i) the inability to detect motion parallel to grating orientation, and (ii) the occlusion of border information, such as the ‘ends’ of the grating, by the surface forming the aperture, Adelson and Movshon's (1982) intcrsection-of-constraints (IOC) model of motion perception describes a two-stage method of disambiguating the motion of 1-D moving stimuli (e.g., gratings) to produce unambiguous motion of two-dimensional (2-D) objects (e.g., plaid patterns) made up of several 1-D components. Specifically, in the IOC model ambiguous 1-D motions extracted by Stage 1 component-selective mechanisms are integrated by Stage 2 pattern-selective mechanisms to produce unambiguous 2-D motion signals. ‘Integration’ in the context of the IOC model involves determining the single motion vector (i.e., combination of direction and speed) which is consistent with the I-D components of a 2-D object. Since the IOC model assumes that 2-D objects undergo pure translation (i.e., without distortion, rotation, etc.), the motion vector consistent with all 1-D components describes the motion of the 2-D object itself. Adelson and Movshon (1982) propose that neural implementation of the computation underlying the IOC model is reflected in the perception of coherent 2-D plaid motion reported when two separately-moving ‘component’ gratings are superimposed. Using these plaid patterns the present thesis assesses the IOC model in terms of its ability to account for the perception of 2-D motion in a variety of circumstances. In the first series of experiments it is argued that the unambiguous motion perceived for a single grating presented within a rectangular aperture (i.e., the Barberpole illusion; Wallach, 1976) reflects application of the IOC computation to the moving 1-D grating and the stationary boundary of the aperture. While contrary to the assumption which underlies the IOC model (viz., that integration occurs between moving 1-D stimuli), evidence consistent with the involvement of the IOC computation in mediating the Barberpole illusion (in which there is only one moving stimulus) is obtained by measuring plaid coherence as a function of aperture shape. It is found that rectangular apertures which bias perceived component motions in directions consistent with plaid direction facilitate plaid coherence, while rectangular apertures which bias perceived component motions in directions inconsistent with plaid direction disrupt plaid coherence. In the second series of experiments, perceived directions of motion of type I symmetrical, type I asymmetrical, and type II plaids are measured with the aim of investigating the deviations in plaid directions reported by Ferrera and Wilson (1990) and Yo and Wilson (1992). Perceived directions of both asymmetrical and type II plaids are shown to deviate away from lOC-predicted directions and towards mean component direction. Furthermore, the magnitude of these deviations is being proportional to the difference between lOC-predicted plaid direction and mean component direction. On the basis of these directional deviations, modification to the IOC model is proposed. In the modified IOC model it is argued that plaid perception involves (i) the activity of Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these pattern-selective mechanisms) involved in implementing the IOC computation, and (ii) component-selective mechanisms which influence plaid perception directly, and ‘extraneously’ to the IOC computation. In the third series of experiments the validity of this modified IOC model, as well as the validity of alternative one-stage models of plaid perception are assessed in relation to perceived directions of plaid-induced MAEs as a function of both plaid direction and mean component direction. It is found that plaid-induced MAEs are shifted away from directions opposite to lOC-predicted plaid direction towards the direction opposite to mean component direction. This pattern of results is taken to be consistent with the modified IOC model which predicts the activity, and adaptation both of mechanisms signalling plaid direction (via implementation of the IOC computation), and ‘extraneous-type’ component-selective mechanisms signalling component directions. Alternative one-stage models which predict the adaptation of only mechanisms signalling plaid direction (the feature-tracking model), or the adaptation only of mechanisms signalling component directions (the distribution-of-activity model), cannot account for the directions of plaid-induced MAEs reported. The ability of the modified IOC model to account for the perceived directions of (i) gratings in rectangular apertures, (ii) various types of plaid in circular apertures, and (iii) directions of plaid-induced MAEs, is interpreted as supporting the proposition that human motion perception is based on a parallel and distributed process involving Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these mechanisms) taken to implement the IOC computation, and component-selective mechanisms taken to provide an 'extraneous' direct contribution to motion perception.

Plastic deformation in the annealed Zr41Ti14Cu12.5Ni10Be22.5 bulk metal glass under indenter

Vickers and nanoindentationswere carried out on an annealed Zr₄₁Ti₁₄Cu_12.5Ni₁₀Be_22.5 bulk metallic glass (BMG), and the evolution of the shear bands in the annealed BMG was investigated and compared to that in the as-cast alloy. Results indicate that the plastic deformation in the BMG with the structure relaxation is accommodated by the semicircular (primary) and radial (secondary) as well as tertiary shear bands. Quantitatively, the shear band density in the annealed alloywas much lower than that in the as-cast alloy. The load-displacement curve of nanoindentation test for the annealed alloy exhibited a more flat serrated flow. The annihilation of free volume caused by the annealing was responsible for the embrittlement of the annealed sample.

Evanescent

Exhibition of original artworks created in 2013. Evanescent is a new series produced in 2013 which premiered at the Castlemaine State Festival 15-24 March 2013. The series revisits a childhood delight and fascination with the projected image and the natural world. For me then, as it is now, a magnifying glass was a wonder; its simple optics twisted light into abstract comas and sci-fi aberrations; able to compact a whole view into a luminous, paradoxically inverted phantom that could fit literally into the palm of my hand. By curling fingers and thumb around the lens and cupping both hands around the elusive rays, and by peering into the space in which I had trapped them, I fancied that I had entered into the secret workings of the eye. Chrysalis, for example, appears as a scenic projection from a hand-held lens and simultaneously as the litter of the forest floor. It is produced with a makeshift camera-obscura. The nebulous silhouettes of trees, some blurred under the passing clouds of a summer wind resolve here and there into crisp lines curled across the surface of a fallen leaf on which a moth chrysalis adheres. The leaf assumes Brobdingnagian proportions and thickness as the evanescent image shrinks and is foreshortened then dissolves in the enlarged dust and grit. It manifests the unique sight anchored at this fixed point, to reveal what we might see if we were to become vegetable or mineral. Near and far, large and small, superimpose, trigonometrically exact in their adjacency and spatial relations, presenting us with a located point of view.Why? I want to understand more intimately the interior of the natural landscape, rather than any ‘scene’ of human presence, or the context of any cultural landmark. In the steep, bush locations in which I am making these images, my means are necessarily makeshift; my camera and an old manual-aperture lens able to be carried in a backpack with a black T-shirt as a 'dark-tent'. The project is not systematic but intuitive and responsive to prevailing conditions and the effect on the projection caused by sun, shade, weather and situation. I am guided by the response of objects, textures and surfaces to the projected image and how they modulate and map it. This is landscape, but not from a human point of view.

Machining of titanium alloy (Ti-6Al-4V)-theory to application

This article correlates laboratory-based understanding in machining of titanium alloys with the industry based outputs and finds possible solutions to improve machining efficiency of titanium alloy Ti-6Al-4V. The machining outputs are explained based on different aspects of chip formation mechanism and practical issues faced by industries during titanium machining. This study also analyzed and linked the methods that effectively improve the machinability of titanium alloys. It is found that the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts. These challenges are correlated and affected by each other. Sawtooth chips cause variation in cutting forces which results in high cyclic stress on cutting tools. On the other hand, low thermal conductivity of titanium alloy causes high temperature. These cause a favorable environment for high tool wear. Thus, improvements in machining titanium alloy depend mainly on overcoming the complexities associated with the inherent properties of this alloy. Vibration analysis kit, high pressure coolant, cryogenic cooling, thermally enhanced machining, hybrid machining and, use of high conductive cutting tool and tool holders improve the machinability of titanium alloy.

Reproduction, egg morphology and development observed in Monographis queenslandicus (Diplopoda: Polyxenidae)

This study provides new insight into penicillate sexual behaviour and eggdevelopment as observed in Monographis queenslandicus Huynh et Veenstra, 2013 (Polyxenidae). The developing eggs were found to have two distinct stages, namely the chorion and pupoid, which both proved to be of 12–14 days duration. Both stages were characterized by distinctive external morphology. Morphological features observed pre ecdysis included the development of a smooth, tough membrane of the chorion. In contrast, the pupoid stage exhibited an embryonic cuticle with tiny spines, which were later being used to rupture the chorion. Additionally, an aperture bordered by protective sensilla located on the anterior of the pupoid is described for the first time.How to cite this article: Huynh C., Veenstra A.A. 2014. Reproduction, egg morphology and development observed in Monographis queenslandicus (Diplopoda: Polyxenidae)