Participatory plant breeding: a way to arrive at better-adapted onion varieties

The search for varieties that are better adapted to organic farming is a current topic in the organic sector. Breeding programmes specific for organic agriculture should solve this problem. Collaborating with organic farmers in such programmes, particularly in the selection process, can potentially result in varieties better adapted to their needs. Here, we assume that organic farmers' perceptive of plant health is broader than that of conventional breeders. Two organic onion farmers and one conventional onion breeder were monitored in their selection activities in 2004 and 2005 in order to verify whether and in which way this broader view on plant health contributes to improvement of organic varieties. They made selections by positive mass selection in three segregating populations under organic conditions. The monitoring showed that the organic farmers selected in the field for earliness and downy mildew and after storage for bulb characteristics. The conventional breeder selected only after storage. Farmers and breeder applied identical selection directions for bulb traits as a round shape, better hardness and skin firmness. This resulted in smaller bulbs in the breeders’ populations, while the bulbs in the farmer populations were bigger than in the original population. In 2006 and 2007 the new onion populations will be compared with each other and the original populations to determine the selection response

Sensory quality of scab-resistant apple cultivars

Twenty-two scab-resistant apple cultivars were harvested in autumn 1999 and evaluated for sensory quality the following October, November and December. Multivariate analysis was effective in describing the comblex relationships and variabillity among the numerous attributes used to characterise apple quality. Crispness, mealiness, skin toughness, apple flavour, sweetness, unripe flavour and overripe flavour were informative attributes describing the variation in the sensory quality. Texture attributes, apple flavour and overripe flavour were affected by storage. Extended storage resulted in an increase in mealiness and overripe flavour and a decrease in crispness, juiciness and apple flavour. Many potential scab-resistant cultivars were suitable for consumption in October: 'Dayton', 'Primicia', 'Retina' and 'Realka'; in November: 'Merlijn', 'Saturn', 'Initial', 'Realka', 'Rajka' and 'Rubinola'; and in December: 'Otava', 'Ecolette', 'Rejka', 'Rubinola', 'Delorina', 'Initial' and 'Resista' and 'Topaz'. This study gives a sensory sharacterisation of scab-resistant cultivars as an indicator of suitability for commercial growing and marketing of low-input apple cultivars

Soft, comfortable polymer dry electrodes for high quality ECG and EEG recording

Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only similar to 10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes

Working out abjection in the Panapompom bêche-de-mer fishery: Race, economic change and the future in Papua New Guinea

This is the accepted version of the following article: Rollason, W. (2010), Working out abjection in the Panapompom bêche-de-mer fishery: Race, economic change and the future in Papua New Guinea. The Australian Journal of Anthropology, 21: 149–170. doi: 10.1111/j.1757-6547.2010.00076.x, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/j.1757-6547.2010.00076.x/abstract.This is a paper about how men from Panapompom, an island in Milne Bay Province of Papua New Guinea (PNG), understand how they relate to white people and imagine the future. Until recently, men from Panapompom understood themselves to be engaged in a project of ‘development’, in which they would become more and more similar to white people. This was a desirable future. However, changes in the way Panapompom men work for money have resulted in a very different imagination of the future—one in which Panapompom people are not getting whiter, but blacker, and hence more and more excluded from the lives to which they aspire. Men now dive for bêche-de-mer, work which they regard as being particularly hard and dangerous. Diving has profound effects on the skin, blackening and hardening it, leading Panapompom men to liken themselves to the machines that create the wealth that white people use. These ‘mechanising’ effects that diving has on the black body lead men to see white people as the sole beneficiaries of the bêche-de-mer industry, and black people as mere tools or extensions. For bêche-de-mer divers, value and desired forms of life are lodged in Australia, Europe or America, while they find themselves excluded from this future by their growing blackness.ESR

Thermal exchange effects on steel thixoforming processes

Steel thixoforging is an innovative semi-solid forming process. It allows the manufacturing of complex parts and minimises the forming load. This work aims to identify and characterise the main feature zones of a thixoforging part. The material flow and the forging load are dependent on the thixoforging speed, the tool temperature and the initial temperature of the slug. The data are obtained for C38 thixoforging steel. A specific extrusion tool was designed that integrates the heating of the tool and the slug. This tool was set up on a high-speed hydraulic press. This work highlights the effects of heat exchange on the microstructure, the internal flow and the mechanical characteristics of thixoforging material. These heat exchanges depend primarily on the working speed and tool temperature. The internal flow is composed of three distinct zones. Among them, only semisolid zone is observed during working. The microstructures of thixoforming C38 steel consist of ferrite, pearlite and bainite

Extruded and injection moulded virgin PA 6/6 as abrasion resistant material

Polyamide (PA6/6) is often used as a tribological pair in abrasion prevalent applications such as hinges and sliders. PA6/6 is frequently processed by injection moulding and extrusion process. It is known that these processes influence the polymers mechanical behaviour, but their influence on the polymers wear response has not been studied. Hence the present research attempts to study the influence of different manufacturing processes on tribological behaviour for PA6/6. Wear tests were performed on a pin abrading tester (DIN 50322). Abrasion resistance of both extruded and injection moulded PA6/6 were tested at different loads (20 and 35 N). Single-pass (nonoverlapping mode) and multipass testing (overlapping mode) were used to understand the influence of clogging of wear debris. It is evidenced that with increasing load the specific wear rate decreases; moreover, fine abrasives tend to reduce the wear rate. In multipass testing a transfer layer clogged on the counterface that acted as a protective agent and lowers wear rate. Poor mechanical strength of injection moulded polymers is apparently compensated by microstructural response for having a similar wear behaviour between extruded and injection moulded PA 6/6. Hence a proper balance between microstructural and mechanical characteristics is an absolute must in PA 6/6 for better wear performance

Combined effect of berry size and postveraison water deficit on grape phenolic maturity and berry texture characteristics (Vitis vinifera L. cv. Portugieser)

The effect of berry size and moderate water deficit on skin phenolic maturity and berry texture behaviour was studied on Portugieser variety (Vitis vinifera L.) under green house conditions. In all berry weight categories (I: 2,01 g) water deficit resulted in reduced sugar concentration due to decreased photosynthetic activity. Interestingly, lower phenolic concentration for unit skin mass was measured in the drought stressed treatment compared to the control, irrespective of berry size. However, the concentration of the phenolic components for one berry was lower in the well watered treatment. This phenomenon was due to the increased skin/flesh ratio of the water stressed vines. Berry skin hardness was probably in connection with its phenolic concentration for unit skin weight. Changes in several berry texture parameters were accompanied by changes in berry size. Berry hardness and skin elasticity increased with berry size in both treatments. On the other hand, skin break force, skin break energy, skin thickness showed increase/decrease only in the case of the stressed vines. This result suggests that texture properties of the water-stressed berries depend on berry size to a greater extent compared to the berries of the non-stressed vines. This phenomenon may be explained by the faster ripening of the smaller and of the water stressed berries

Comparison of synthetic membranes in the development of an in vitro feeding system for Dermanyssus gallinae

Although artificial feeding models for the poultry red mite (Dermanyssus gallinae) most frequently use biological membranes consisting of day-old chick skin, there are ethical considerations associated with the use of skin. The few studies reported in the literature that have investigated the use of synthetic membranes to feed D. gallinae in vitro have reported limited success. The current study describes an investigation into the use of synthetic membranes made from either Nescofilm® or rayon and silicone, used either alone or in combination with different feather or skin extracts, as well as the use of capillary tubes. In all, 12 different treatments were used, and the feeding rate of D. gallinae was compared to that of day-old chick skin. Allowing mites to feed on a membrane consisting of Nescofilm with a skin extract resulted in the highest proportion of mites feeding (32.3%), which was not significantly different to the feeding rate of mites on day-old chick skin (38.8%). This study confirms that synthetic membranes can be used to feed D. gallinae artificially. Further optimization of the membrane and mite storage conditions is still necessary, but the study demonstrates a proof of concept