205 research outputs found

    New dung beetles at work in Western Australia

    Get PDF
    Two kinds od dung beetles are active in the agricultural areas of Western australia. In one group are the native beetles which are mainly active in winter, and in the other group are beetles introduced from overseas. The introduced beetles are mainly active in summer and have already produced some spectacular result

    Implications of Biomechanical Characters of Subterranean Clover on Feeding by Redlegged Earth Mite and Intake by Sheep

    Get PDF
    The biomechanical strength of cultivars of subterranean clover (Trifolium subterraneum) that were either resistant or susceptible to feeding by redlegged earth mite was measured as the force required to penetrate their leaves with a small, tubular punch. Cotyledons and trifoliate leaves of cultivars resistant to redlegged earth mite had a higher resistance to penetration than cultivars susceptible to redlegged earth mite. Cotyledons needed a higher force to penetrate than trifoliate leaves. The possible implications for intake by ruminants of differences between the cultivars in biomechanical characters are also considered

    Photoevaporation versus enrichment in the cradle of the Sun

    Full text link
    The presence of short-lived radioisotopes (SLRs) 26-Al and 60-Fe in the Solar system places constraints on the initial conditions of our planetary system. Most theories posit that the origin of 26-Al and 60-Fe is in the interiors of massive stars, and they are either delivered directly to the protosolar disc from the winds and supernovae of the massive stars, or indirectly via a sequential star formation event. However, massive stars that produce SLRs also emit photoionising far and extreme ultraviolet radiation, which can destroy the gas component of protoplanetary discs, possibly precluding the formation of gas giant planets like Jupiter and Saturn. Here, we perfom N-body simulations of star-forming regions and determine whether discs that are enriched in SLRs can retain enough gas to form Jovian planets. We find that discs are enriched and survive the photoionising radiation only when the dust radius of the disc is fixed and not allowed to move inwards due to the photoevaporation, or outwards due to viscous spreading. Even in this optimal scenario, not enough discs survive until the supernovae of the massive stars and so have zero or very little enrichment in 60-Fe. We therefore suggest that the delivery of SLRs to the Solar system may not come from the winds and supernovae of massive stars.Comment: 13 pages, 4 figures, accepted for publication in MNRA

    Co-creation to Develop Interventions to Facilitate Deep Reflection for Dental Students

    Get PDF
    Background: Deep reflective practice is important in healthcare education to allow students to explore emotions associated with the learning experience, access deeper learning and develop their personal and professional identity. Previous research demonstrated that the current methods of reflective practice using logbooks at the end of a clinical session to facilitate reflection within this setting were viewed as suboptimal by staff and student users. To address this problem co-creation, or a ‘students as partners’ approach, was used to develop and implement a comprehensive intervention to facilitate deep reflection for undergraduate dental students. This included the production of educational resources, and development of an online safe space to reflect.Approach: In this paper we discuss the process of using co-creation with undergraduate dental students as a research methodology to successfully produce curricular change with respect to reflective practice by involving the voice and experience of student partners. These student partners were part of a team that included researchers and teaching staff and worked with other stakeholders within the institution within a wider team.Evaluation: This paper demonstrates the positive benefits of using co-creation with undergraduate dental students for students such as increased confidence, developing professional and personal skills and impacting meaningful change.Reflection: For researchers and educators, the process gave motivation and enjoyment in curricular development to address pedagogical problems and ensured that the developed intervention was sustainable and appropriate. The paper discusses benefits and challenges of co-creation to develop curricular change. This co-creation approach is recommended for solving similar problems in healthcare education

    Sustainable pest management in rainfed farming systems

    Get PDF
    Insect pests are estimated to cause losses of 16% to world attainable crop production with post-harvest losses another 10%, in spite of widespread use of pesticides. Losses due to pests have been estimated for key rainfed crops in different regions of the world. Pest species attack every phenological stage of crop growth; sometimes they are the same species and sometimes different. No one tool can be used to successfully control a pest; integrated pest management principles have been widely adopted and include determining the economic threshold at which control is cost effective. Chemical control is widely used but excessive use can cause resistance in the insect and adverse environmental effects. The enhancement of use of natural enemies of pest insects, and use of crop cultivars resistant to the insects are both very important. Crop management practices used to reduce the impact of pests include crop rotations, intercropping, sowing rates, sowing time and soil tillage. Management of pests requires growers to understand the interactions between the pests and crops in their regions and to use the most appropriate tools to reduce the potential damage. While no one system would be applicable to a crop or to a pest in all rainfed farming systems, some general principles are relevant across region

    Adaptive Optics system of the Evanescent Wave Coronagraph (EvWaCo): optimised phase plate and DM characterisation

    Full text link
    The Evanescent Wave Coronagraph (EvWaCo) is an achromatic coronagraph mask with adjustable size over the spectral domain [600nm, 900nm] that will be installed at the Thai National Observatory. We present in this work the development of a bench to characterise its Extreme Adaptive Optics system (XAO) comprising a DM192 ALPAO deformable mirror (DM) and a 15x15 Shack-Hartmann wavefront sensor (SH-WFS). In this bench, the turbulence is simulated using a rotating phase plate in a pupil plane. In general, such components are designed using a randomly generated phase screen. Such single realisation does not necessarily provide the wanted structure function. We present a solution to design the printed pattern to ensure that the beam sees a strict and controlled Kolmogorov statistics with the correct 2D structure function. This is essential to control the experimental conditions in order to compare the bench results with the numerical simulations and predictions. This bench is further used to deeply characterise the full 27 mm pupil of the ALPAO DM using a 54x54 ALPAO SH-WFS. We measure the average shape of its influence functions as well as the influence function of each single actuator to study their dispersion. We study the linearity of the actuator amplitude with the command as well as the linearity of the influence function profile. We also study the actuator offsets as well as the membrane shape at 0-command. This knowledge is critical to get a forward model of the DM for the XAO control loop

    Detached Leaf Assay to Screen for Host Plant Resistance to Helicoverpa armigera

    Get PDF
    The noctuid Helicoverpa armigera (Hübner) is a major insect pest of chickpea Cicer arietinum L., pigeonpea Cajanus cajan (L.) Millsp., peanut Arachis hypogaea L., and cotton Gossypium spp., and host plant resistance is an important component for managing this pest in different crops. Because of variations in insect density and staggered flowering of the test material, it is difficult to identify cultivars with stable resistance to H. armigera across seasons and locations. To overcome these problems, we standardized the detached leaf assay to screen for resistance to this pest in chickpea, pigeonpea, peanut, and cotton under uniform insect pressure under laboratory conditions. Terminal branch (three to four fully expanded leaves) of chickpea, first fully expanded leaf of cotton, trifoliate of pigeonpea, or quadrifoliate of peanut, embedded in 3% agar-agar in a plastic cup/jar of appropriate size (250-500-ml capacity) infested with 10-20 neonate larvae can be used to screen for resistance to H. armigera. This technique keeps the leaves in a turgid condition for ~1 wk. The experiments can be terminated when the larvae have caused >80% leaf damage in the susceptible check or when differences in leaf feeding between the resistant and susceptible checks are maximum. Detached leaf assay can be used as a rapid screening technique to evaluate germplasm, segregating breeding materials, and mapping populations for resistance to H. armigera in a short span of time with minimal cost, and under uniform insect infestation. It also provides useful information on antibiosis component of resistance to the target insect pest
    • …
    corecore