2,079 research outputs found

    Suppression of the large pine weevil Hylobius abietis (L.) (Coleoptera: Curculionidae) in pine stumps by entomopathogenic nematodes with different foraging strategies

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    Hylobius abietis is the most important pest of reforestation in Northern Europe. Weevils develop in stumps of felled conifers and emerging adults feed on and kill young trees. In trials conducted in each of 3 years, entomopathogenic nematodes were applied around pine stumps containing late instar weevils. Since these immature weevils are sedentary and occur within stumps at varying depths in soil, it is predicted that nematodes with a cruise foraging strategy, such as Heterorhabditis spp., should be most effective. The three commercially available species used in our trials, H. megidis, Steinernema feltiae, and S. carpocapsae, have cruise, intermediate and ambush strategies, respectively. We also included the indigenous species H. downesi and a strain of S. feltiae isolated from an Irish coniferous forest. Heterorhabditis downesi suppressed emergence of adult weevils in 2 of 3 trials; and commercial S. feltiae and H. megidis NLH85 in 1 trial each. Stump excavation showed that H. downesi parasitized 55â63% of developing weevils; this was matched by H. megidis NLH85 and S. carpocapsae in 2 and 1 years, respectively. A higher proportion of larvae (46%) than of pupae (32%) or callow adults (30%) were parasitized by nematodes. All nematodes, including S. carpocapsae, parasitized weevils 40â49 cm from the bole of the stump and 30â39 cm below soil level. We conclude that heterorhabditids, particularly H. downesi, have greatest potential against pine weevils in stumps, but that a reputation as an ambush forager should not exclude a species such as S. carpocapsae from trials against sedentary subterranean insect pests

    Optimizing application of entomopathogenic nematodes to manage large pine weevil, Hylobius abietis L. (Coleoptera:Curculionidae) populations developing in pine stumps, Pinus sylvestris

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    Hylobius abietis develops in stumps of recently felled coniferous trees, and adults emerge to feed on and kill young seedlings. Entomopathogenic nematodes applied to stumps containing late instar larvae and pupae can reduce the number of adults emerging. We tested the feasibility of reduced application rate and volume during a broader window of application in field trials in 2004 and 2005. Application at the standard rate of 3.5 million infective juveniles per stump suppressed the number of adults emerging by up to 79–85% relative to controls for Heterorhabditis downesi, 57–64% for Steinernema carpocapsae and 51–56% for S. feltiae. When the application rate was halved, only H. downesi gave a significant reduction in emergence (75–79%). Nematodes applied in April, May or June significantly reduced weevil populations, and application of nematode-killed insects in May was as effective as an aqueous suspension. A fourfold reduction in application volume from 500 to 125 ml per stump did not affect the percentage of weevils parasitized, and stump excavation revealed that even at the reduced volume, both S. carpocapsae (ambusher) and H. downesi (cruiser) parasitized weevils 40–49 cm from the bole and 40–49 cm below soil level. A higher percentage of larvae (60%) were infected than either pupae (36%) or callow adults (18%). Our trials show promise for expanding the use of entomopathogenic nematodes against pine weevil, as the standard application rate can be halved, and the volume reduced to 25% of the standard without significant loss of efficacy, and there is a wide window of opportunity for application, even when soil temperatures are as low as 9 °C

    Optimizing application of entomopathogenic nematodes to manage large pine weevil, Hylobius abietis L. (Coleoptera:Curculionidae) populations developing in pine stumps, Pinus sylvestris

    Get PDF
    Hylobius abietis develops in stumps of recently felled coniferous trees, and adults emerge to feed on and kill young seedlings. Entomopathogenic nematodes applied to stumps containing late instar larvae and pupae can reduce the number of adults emerging. We tested the feasibility of reduced application rate and volume during a broader window of application in field trials in 2004 and 2005. Application at the standard rate of 3.5 million infective juveniles per stump suppressed the number of adults emerging by up to 79–85% relative to controls for Heterorhabditis downesi, 57–64% for Steinernema carpocapsae and 51–56% for S. feltiae. When the application rate was halved, only H. downesi gave a significant reduction in emergence (75–79%). Nematodes applied in April, May or June significantly reduced weevil populations, and application of nematode-killed insects in May was as effective as an aqueous suspension. A fourfold reduction in application volume from 500 to 125 ml per stump did not affect the percentage of weevils parasitized, and stump excavation revealed that even at the reduced volume, both S. carpocapsae (ambusher) and H. downesi (cruiser) parasitized weevils 40–49 cm from the bole and 40–49 cm below soil level. A higher percentage of larvae (60%) were infected than either pupae (36%) or callow adults (18%). Our trials show promise for expanding the use of entomopathogenic nematodes against pine weevil, as the standard application rate can be halved, and the volume reduced to 25% of the standard without significant loss of efficacy, and there is a wide window of opportunity for application, even when soil temperatures are as low as 9 °C

    Modelling Herschel observations of infrared-dark clouds in the Hi-GAL survey

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    We demonstrate the use of the 3D Monte Carlo radiative transfer code PHAETHON to model infrared-dark clouds (IRDCs) that are externally illuminated by the interstellar radiation field (ISRF). These clouds are believed to be the earliest observed phase of high-mass star formation, and may be the high-mass equivalent of lower-mass prestellar cores. We model three different cases as examples of the use of the code, in which we vary the mass, density, radius, morphology and internal velocity field of the IRDC. We show the predicted output of the models at different wavelengths chosen to match the observing wavebands of Herschel and Spitzer. For the wavebands of the long- wavelength SPIRE photometer on Herschel, we also pass the model output through the SPIRE simulator to generate output images that are as close as possible to the ones that would be seen using SPIRE. We then analyse the images as if they were real observations, and compare the results of this analysis with the results of the radiative transfer models. We find that detailed radiative transfer modelling is necessary to accurately determine the physical parameters of IRDCs (e.g. dust temperature, density profile). This method is applied to study G29.55+00.18, an IRDC observed by the Herschel Infrared Galactic Plane survey (Hi-GAL), and in the future it will be used to model a larger sample of IRDCs from the same survey.Comment: MNRAS accepted, High resolution paper available at http://www.astro.cardiff.ac.uk/pub/Dimitrios.Stamatellos/Publications.htm

    Women's views on screening for Type 2 diabetes after gestational diabetes: a systematic review, qualitative synthesis and recommendations for increasing uptake.

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    AIM: Many women do not attend recommended glucose testing following a pregnancy affected by gestational diabetes (GDM). We aimed to synthesize the literature regarding the views and experiences of women with a history of GDM on postpartum glucose testing, focusing on barriers and facilitators to attendance. METHODS: We systematically identified qualitative studies that examine women's experiences following GDM relating to glucose testing (diabetes screening) or experience of interventions to promote uptake of testing. We conducted a thematic synthesis to develop descriptive and then analytical themes, then developed recommendations to increase uptake based on the findings. We evaluated the quality of each study and the confidence that we had in the recommendations using published checklists. RESULTS: We included 16 articles after screening 23 160 citations and 129 full texts. We identified four themes of influences relating to the healthcare system and personal factors that affected both ability and motivation to attend: relationship with health care, logistics of appointments and tests, family-related practicalities and concern about diabetes. We developed 10 recommendations addressing diabetes risk information and education, and changes to healthcare systems to promote increased attendance at screening in this population, most with high or moderate confidence. CONCLUSIONS: We have identified a need to improve women's understanding about Type 2 diabetes and GDM, and to adjust healthcare provision during and after pregnancy to decrease barriers and increase motivation for testing. Encouraging higher uptake by incorporating these recommendations into practice will enable earlier management of diabetes and improve long-term outcomes.R.D. is funded by a PhD studentship from the National Institute for Health Research (NIHR) School for Primary Care Research (SPCR; SPCR-S-S102). This paper presents independent research funded by the NIHR SPCR. The views expressed are those of the author(s) and not necessarily those of the NIHR, the NHS or the Department of Health. R.W. is funded by an NIHR Academic Clinical Fellowship. S.G. is supported by the Medical Research Council (MC_UU_12015/4). S.G. is an NIHR Senior Investigator. The University of Cambridge has received salary support in respect of S.G. from the NHS in the East of England through the Clinical Academic Reserve. J.U-S. is funded by a Cancer Research UK Cancer Prevention Fellowship (C55650/A21464)

    Virtual Reality & Gamification for Pre-Occupancy Training

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    The objective of this research is to analyze and compare user behavior and learning retention via gamified and non-gamified virtual reality for use in pre-occupancy training. After completing trials for both gamified and non-gamified virtual reality we issued a standardized post-experience survey to collect data on what the participants learned, then compared and analyzed the results. The benefits of virtual reality and gamification have both been extensively studied and both suggest they are independently effective teaching tools. In our trials we have found that participants who went through the gamified virtual reality training were 50% more likely to come away with the desired learning objectives than participants who went through the non-gamified virtual reality. The benefits of virtual reality and gamification can be effectively combined and retain the benefits of that learning method in this situation. Based on our small sample and our literature review this technology can be used to train a more informed population regarding the effective operation of passive building systems.https://pdxscholar.library.pdx.edu/research_based_design/1085/thumbnail.jp

    Client or Volunteer? Understanding Neoliberalism and Neocolonialism Within International Volunteer Health Work

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    As international volunteer health work increases globally, research pertaining to the social organizations that coordinate the volunteer experience in the Global South has severely lagged. The purpose of this ethnographic study was to critically examine the social organizations within Canadian NGOs in the provision of health work in Tanzania. Multiple, concurrent data collection methods, including text analysis, participant observation and in-depth interviews were utilized. Data collection occurred in Tanzania and Canada. Neoliberalism and neocolonialism were pervasive in international volunteer health work. In this study, the social relations—“volunteer as client,” “experience as commodity,” and “free market evaluation”—coordinated the volunteer experience, whereby the volunteers became “the client” over the local community and resulting in an asymmetrical relationship. These findings illuminate the need to generate additional awareness and response related to social inequities embedded in international volunteer health work

    The initial conditions of isolated star formation -- IX. Akari mapping of an externally heated pre-stellar core

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    We present observations of L1155 and L1148 in the Cepheus molecular cloud, taken using the FIS instrument on the Akari satellite. We compare these data to submillimetre data taken using the SCUBA camera on the JCMT, and far-infrared data taken with the ISOPHOT camera on board the ISO satellite. All of the data show a relation between the position of the peak of emission and the wavelength for the core of L1155. We interpret this as a temperature gradient. We fit modified blackbody curves to the spectral energy distributions at two positions in the core and see that the central core in L1155 (L1155C) is approximately 2 degrees warmer at one edge than it is in the centre. We consider a number of possible heating sources and conclude that the A6V star BD+67 1263 is the most likely candidate. This star is at a distance of 0.7 pc from the front of L1155C in the plane of the sky. We carry out radiative transfer modelling of the L1155C core including the effects from the nearby star. We find that we can generate a good fit to the observed data at all wavelengths, and demonstrate that the different morphologies of the core at different wavelengths can be explained by the observed 2 degree temperature gradient. The L1148 core exhibits a similar morphology to that of L1155C, and the data are also consistent with a temperature gradient across the core. In this case, the most likely heating source is the star BD197053. Our findings illustrate very clearly that the apparent observed morphology of a pre-stellar core can be highly dependent on the wavelength of the observation, and that temperature gradients must be taken into account before converting images into column density distributions. This is important to note when interpreting Akari and Spitzer data and will also be significant for Herschel data.Comment: 15 pages, 15 figures, accepted by MNRA

    Profiling filaments: comparing near-infrared extinction and submillimetre data in TMC-1

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    Interstellar filaments are an important part of star formation. To understand the structure of filaments, cross-section profiles are often fitted with Plummer profiles. This profiling is often done with submm studies, such as Herschel. It would be convenient if filament properties could also be studied using groundbased NIR data. We compare the filament profiles obtained by NIR extinction and submm observations to find out if reliable profiles can be derived using NIR data. We use J-, H-, and K-band data of a filament north of TMC-1 to derive an extinction map from colour excesses of background stars. We compare the Plummer profiles obtained from extinction maps with Herschel dust emission maps. We present 2 methods to estimate profiles from NIR: Plummer profile fits to median Av of stars or directly to the Av of individual stars. We compare the methods by simulations. In simulations extinction maps and the new methods give correct results to within ~10-20 for modest densities. Direct fit to data on individual stars gives more accurate results than extinction map, and can work in higher density. In profile fits to real observations, values of Plummer parameters are generally similar to within a factor of ~2. Although parameter values can vary significantly, estimates of filament mass usually remain accurate to within some tens of per cent. Our results for TMC-1 are in agreement with earlier results. High resolution NIR data give more details, but 2MASS data can be used to estimate profiles. NIR extinction can be used as an alternative to submm observations to profile filaments. Direct fits of stars can also be a valuable tool. Plummer profile parameters are not always well constrained, and caution should be taken when making fits. In the evaluation of Plummer parameters, one can use the independence of dust emission and NIR data and the difference in the shapes of the confidence regions.Comment: accepted to Astronomy & Astrophysics; abstract has been shortened for astrop
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