Borromean rays and hyperplanes

Three disjoint rays in euclidean 3-space form Borromean rays provided their union is knotted, but the union of any two components is unknotted. We construct infinitely many Borromean rays, uncountably many of which are pairwise inequivalent. We obtain uncountably many Borromean hyperplanes.Comment: 41 pages, 30 figures (19 with captions, 11 inline

The end sum of surfaces

End sum is a natural operation for combining two noncompact manifolds and has been used to construct various manifolds with interesting properties. The uniqueness of end sum has been well-studied in dimensions three and higher. We study end sum -- and the more general notion of adding a 1-handle at infinity -- for surfaces and prove uniqueness results. The result of adding a 1-handle at infinity to distinct ends of a surface with compact boundary is uniquely determined by the chosen ends and the orientability of the 1-handle. As a corollary, the end sum of two surfaces with compact boundary is uniquely determined by the chosen ends. Unlike uniqueness results in higher dimensions, which rely on isotopy uniqueness of rays, our results rely fundamentally on a classification of noncompact surfaces.Comment: 40 pages, 29 figure

Unpacking the foundational dimensions of work integration social enterprise: the development of an assessment tool

Purpose The aim of this exploratory, mixed methods study was to develop and test a tool that identifies foundational dimensions of work integration social enterprises (WISEs) for use in empirical studies and enterprise self-assessment. Construction of the initial prototype was based upon a review of the literature and prior qualitative research by the authors. Design/methodology/approach A 20-item question pool with a four-point response scale was constructed to explore WISE business and employment practices and strategies for worker growth and development. Three sequential field tests were conducted with the prototype – the first with 5 Canadian WISEs, the second with 14 WISEs in the UK and the third with 6 Canadian WISEs involved in an outcome study in the mental health sector. Each field test included completion of the questionnaire by persons with managerial responsibility within the WISE and evaluative feedback captured through questions on the applicability and interpretability of the items. Findings Testing of the prototype instrument revealed the inherent diversity in the field and the difficulty in creating questions that both embrace that diversity and produce unidimensional variables definable along a spectrum. A number of challenges with question structure were identified and have been modified throughout the iterative testing process. Research limitations/implications This study identified central domains for inclusion in a multi-dimensional WISE assessment tool. Further testing will help further refine scaling and establish psychometric properties. Originality/value This measure will provide a descriptive profile of WISEs across sectors and identify WISE core dimensions for research and organizational development. </jats:sec

Characterisation and applications of marine derived calcium phosphates and carbonates

The purpose of this study was to characterise extensively, and process fishbone derived and shellfish mineral powders, followed by the investigation of potential applications for these materials. A variety of spectroscopic, microscopic and analytical techniques were used in this study, including FT-IR, SS-NMR, pXRD, SEM, ICP-MS, and laser diffraction particle sizing. These techniques enabled tracking of changes in the chemical and physical nature of the materials as a function of processing techniques. The potential applications covered in this study were the investigation of the immobilisation of the enzyme malL to bone materials with the aid of a coupling reagent, as well as investigations into the removal of various ionic species from aqueous water samples. Differences in the mineral components of the materials between species were insignificant. Slight variations were found in the organic component of the bone materials, however these were most likely due to varying levels of oils remaining in the materials after processing by Plant and Food, Nelson, as the organic matter was found to be primarily composed of collagen in all species. Thermally treating the bone samples to 800 oC was found to be the most effective and reliable method for removing the organic content from the bone materials. Synthetic HAp powders were successfully produced through the digestion and reprecipitation of bone-derived materials and an optimum method to produce these powders was devised. Promising yet unexpected results were found in the enzyme immobilisation studies, results suggest that there is the potential for some enzymes to be bound to the bone materials, however more thorough investigations are required to understand the complex system. Promising results were also found from the adsorption experiments involving ionic species. The species trialled were Ni²⁺, Cd²⁺, Sr²⁺, AsO₄³⁻ and F⁻. Bone materials heated to 500 oC were consistently the most effective material for adsorption of the divalent metal cation species trialled. Adsorptions between this material and the divalent nickel and cadmium ions were found to follow pseudo second order kinetics, with Langmuir type isotherm behaviour. Fluoride adsorptions were also found to have a Langmuir type isotherm however the adsorption kinetics of this system were not investigated. Overall the results from this study outline a few potential applications, which if investigated and developed further could add significant value to materials which are currently produced in high volumes as waste by-products from the fishing industry in New Zealand

Building an IDE for an embedded system using web technologies

Implementing an understandable, accessible and effective user interface is a major challenge for many products in the microcontroller and embedded computing community. Bela, an embedded system for ultra-low latency audio and sensor processing, features a browser-based integrated development environment (IDE) using web technologies (Node.js, HTML5 and CSS). This methodology has allowed us to create an IDE that is simplified and intuitive for beginners while still being useful to those more advanced, thus supporting users as they evolve in expertise

New and Emerging Disease Threats to Forest Plantations in Sarawak Borneo, Malaysia

The planted forest area in Sarawak is the largest planted forest in Malaysia, which has been developed since 1997 to sustain the decline in the production of natural forests. As of December 2021, the total area of plantation forests reached 551,704 hectares (ha), dominated by fast-growing exotic species mainly Acacia species (55%), Falcataria moluccana (15%) and Eucalyptus (14%). The study showed Acacia was infected with red root rot disease of Ganoderma philippii and brown root rot of Phellinus noxius, Ceratocystis wilt disease caused by Ceratocystis. fimbriata sensu stricto (s.s) complex and pink disease caused by Erythricium salmonicolor, while F. moluccana was infected by gall disease namely Uromycladium falcatarium. Eucalyptus pellita diseases were infected namely by G. philippii red root rot disease, stem canker disease caused by Botryosphaeriaceae pathogen and bacterial wild disease caused by Ralstonia solanacearum. Ceratocystis wilt disease of Acacia mangium shows disease incidence (DI) accounted at 68% (serious) as compared with other diseases observed in this study. This will be the first baseline study that is conducted to observe and assess the diversity of the present, new and emerging pathogens and the damage they cause to exotic planted species of Sarawak

Design and Development of an Exoskeleton Prototype Arm Utilising Electromyography

Individuals who lack or have significant difficulties utilising their arms and hands may benefit from having an exoskeletal arm to gain some independence in their daily lives. This paper outlines the design and implementation of a prototype electro-mechanical arm. The mechanisms utilise cable-drawn pulleys to provide controlled-angle three degrees of freedom (DOF) for index, middle and ring and the shoulder. The elbow has a single DOF. The aim was to build a prototype wearable prosthetic mechanism for the whole arm that could perform some basics daily tasks. Furthermore, it was intended that the prosthetic mechanisms assist with some physiotherapy activities, which might be helpful for individuals with muscle degenerative diseases. The arm was controlled by either utilising electromyography (EMG) signals recorded by placing sensors on the arm or by utilising a joystick interface. The actuation of its DC motors was programmed to reflect the user's muscle activities and to allow the user to control the modules smoothly and accurately. A graphical 3D animation was implemented in MATLAB© Simulink© to demonstrate the arm’s operation, while the hardware was interfaced through LabVIEW©. The components were designed in Solidworks and 3D printed. The prosthetic mechanism was able to lift objects up to 2 kg. The mechanism provided accurate position control for moving objects and physiotherapy. The basic daily activity of drinking was achieved; however, this required development

Whey protein consumption after resistance exercise reduces energy intake at a post-exercise meal

Purpose - Protein consumption after resistance exercise potentiates muscle protein synthesis, but its effects on subsequent appetite in this context are unknown. This study examined appetite and energy intake following consumption of protein- and carbohydrate-containing drinks after resistance exercise. Methods - After familiarisation, 15 resistance training males (age 21 ± 1 years, body mass 78.0 ± 11.9 kg, stature 1.78 ± 0.07 m) completed two randomised, double-blind trials, consisting of lower-body resistance exercise, followed by consumption of a whey protein (PRO 23.9 ± 3.6 g protein) or dextrose (CHO 26.5 ± 3.8 g carbohydrate) drink in the 5 min post-exercise. An ad libitum meal was served 60 min later, with subjective appetite measured throughout. Drinks were flavoured and matched for energy content and volume. The PRO drink provided 0.3 g/kg body mass protein. Results - Ad libitum energy intake (PRO 3742 ± 994 kJ; CHO 4172 ± 1132 kJ; P = 0.007) and mean eating rate (PRO 339 ± 102 kJ/min; CHO 405 ± 154 kJ/min; P = 0.009) were lower during PRO. The change in eating rate was associated with the change in energy intake (R = 0.661, P = 0.007). No interaction effects were observed for subjective measures of appetite. The PRO drink was perceived as creamier and thicker, and less pleasant, sweet and refreshing (P < 0.05). Conclusion - These results suggest whey protein consumption after resistance exercise reduces subsequent energy intake, and this might be partially mediated by a reduced eating rate. Whilst this reduced energy intake is unlikely to impair hypertrophy, it may be of value in supporting an energy deficit for weight loss