832 research outputs found

    Biologische Bekämpfung von Drahtwürmern mit entomopathogenen Pilzen

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    We investigated the virulence of three European isolates of the entomopathogenic fungus (EPF) Metarhizium anisopliae against three wireworm species which are important pests of arable crops and vegetables in Europe: Agriotes lineatus, A. obscurus and A. sputator. In laboratory experiments, up to 90 % of the wireworms were killed by the fungus, depending on the fungal isolate and the wireworm species. Speed of kill was generally low with first wireworms showing unambiguous signs of fungal disease after two to three weeks. Maximum mortality rates were reached after six to eight weeks post inoculation. The next steps of this investigation will be to determine the most suitable fungal isolate and the validation of the laboratory results under greenhouse and field conditions. The aim of the study is to develop an easily applicable formulation with the most effective EPF isolate as the main active ingredient. In addition, applications of the EPF will be combined with entomoparasitic nematodes (EPNs) and repellent semiochemicals. Possible synergistic interactions between EPFs and EPNs or repellents may contribute significantly to improved biological control of wireworms

    Where energy flows, passion grows: testing a moderated mediation model of work passion through a cross-cultural lens

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    This study examines how and when passionate leaders can instigate work passion in their followers. We propose relational energy as a social interaction mediator that can facilitate the crossover of work passion from leader to followers. Additionally, we introduce a moderator of culture (Anglo culture, e.g., Canada vs. Confucian Asian culture, e.g., China) as it plays a vital role in the dynamics of interpersonal relations within a leader-follower dyad. We collected two-wave data from MBA students of two Confucian Asian countries (China and Singapore, n = 120) and two Anglo countries (Canada and Australia, n = 265) to test our moderated mediation model. The results show that interactions with passionate leaders can generate relational energy in followers and subsequently lead to followers’ passion for work. Furthermore, the findings shed light on the moderating effect of culture, such that the leader-follower work passion relationship via follower relational energy was stronger for followers from Anglo culture than the followers from Confucian Asian culture. Limitations of the study and directions for future research are discussed

    Effect of hadronic cascade time on freeze-out properties of Identified Hadrons in Au+Au Collisions at sNN\sqrt{s_{NN}} = 7.7-39 GeV from AMPT Model

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    We report the transverse momentum pTp_T spectra of identified hadrons (π±\pi^\pm, K±K^\pm and p(pˉ)p(\bar p)) in Au+Au collisions at sNN\sqrt{s_{NN}} = 7.7 - 39 GeV from A Multi Phase Transport Model with string melting effect (AMPT-SM). During this study, a new set of parameters are explored to study the effect of hadronic cascade by varying hadronic cascade time tmaxt_{max} = 30 ffm/cc and 0.4 ffm/cc. No significant effect of this change is observed in the pTp_T spectra of light hadrons and the AMPT-SM model reasonably reproduces the experimental data. To investigate the kinetic freeze-out properties the blast wave fit is performed to the pTp_T spectra and it is found that the blast wave model describes the AMPT-SM simulations well. We additionally observe that the kinetic freeze-out temperature (TkinT_{kin}) increases from central to peripheral collisions, which is consistent with the argument of short-lived fireball in peripheral collisions. Whereas the transverse flow velocity, shows a decreasing trend from central to peripheral collisions indicating a more rapid expansion in the central collisions. Both, $T_{kin}$ and show a weak dependence on the collision energy at most energies. We also observe a strong anti-correlation between TkinT_{kin} and . The extracted freeze-out parameters from the AMPT-SM simulations agree with the experimental data as opposed to earlier studies that reported some discrepancies. Whereas, no significant effect is found on the freeze-out parameters by varying the tmaxt_{max}. We also report the pTp_T spectra of light hadrons and their freeze-out parameters by AMPT-SM simulations at sNN\sqrt{s_{NN}} = 14.5 GeV, where no experimental data is available for comparison. Overall, the set of parameters used in this study well describes the experimental data at BES energies.Comment: 12 pages, 7 figures, 2 table

    Study of Baryon number transport using model simulations in pppp collisions at LHC Energies

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    We report on the excitation function of anti-baryon to baryon ratios (p‾/p\overline{p}/p, {\alam /\lam} and {\axi / \xim}) in pppp collisions at {\sqrts} = 0.9, 2.76, 7 TeV from DPMJET-III, Pythia~8, EPOS~1.99, and EPOS-LHC model simulations. To study the predictions of these models at {\sqrts} = 13.6 TeV. The anti-baryon to baryon ratios are extremely important for the study of baryon number transport mechanisms. These ratios help determine the carriers of the baryon number and in the extraction of baryon structure information. Even though all models show a good agreement between model simulations and data, the ratios extracted from DPMJET-III model closely describes data at all energies. It is observed that these ratios converge to unity for various model predictions. This convergence also indicates that the anti-baryon to baryon ratios follow the mass hierarchy, such that the hyperon specie containing more strange quarks ({\alam /\lam} and {\axi / \xim}) approaches unity faster than specie containing fewer strange quarks (p‾/p\overline{p}/p). It is also observed that the B‾/B\overline{B}/B ratio approaches unity more rapidly with the increase in {\sqrts} energy. At lower energies we observe an excess production of baryons over anti-baryons. However, this effect vanishes at higher energies due to the baryon-anti-baryon pair production and the baryon-anti-baryon yield becomes equal. Using model simulations, we additionally compute the asymmetry, (A\equiv\frac{N_{p}-N_{\bar{p}}}N_{p}+N_{\bar{p}}}) for protons. The asymmetry shows a decreasing trend with increase in energy from 0.9 to 7 TeV for all energies. This asymmetry trend is confirmed by model predictions at {\sqrts} = 13.6 TeV which will help to put possible constraints on model calculations at {\sqrts} = 13.6 TeV once the Run-III data for LHC becomes available.Comment: 14 pages, 8 figures, 2 table

    Virulence of in vivo and in vitro produced conidia of Metarhizium brunneum strains for control of wireworms

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    Wireworms are the soil inhabiting larvae of click beetles and can cause severe damage to arable crops such as potatoes (Solanum tuberosum, L.). Several strains of the entomopathogenic fungus Metarhizium brunneum (Petch) are pathogenic to wireworms. In this study, three European strains of M. brunneum were tested in the laboratory against the most damaging wireworm species in Europe, Agriotes lineatus (L.), Agriotes obscurus (L.) and Agriotes sputator (L.). A Swiss strain, isolated from an A. obscurus cadaver, proved to be most effective, killing up to 73% of A. lineatus and 83% A. obscurus individuals, respectively. The median lethal time (LT50) was 21 days post inoculation (dpi) for A. lineatus and 14 dpi for A. obscurus. The strain did not lose virulence through subsequent cultivation on artificial medium and thus seems to be suitable for mass production as a biocontrol agent for wireworm control

    Applying a mixed-method approach to improve on-the-job learning and job satisfaction in a cohort of interns at a university hospital

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    Introduction: Job satisfaction is vital for the optimal functioning of medical practitioners. Herein, we report our experience of restructuring the internship program by identifying the gaps, developing, implementing strategies to overcome gaps and sharing the results of the pre-implementation and post-implementation audit, as an example for establishing a system for improving intern\u27s work-based learning and satisfaction in a university hospital setting.Methods: Using Kern\u27s six-step instructional model, a prospective mixed-method study was conducted at Aga Khan University Hospital. In phase 1 (2013) gaps were identified by evaluating various aspects of the internship program. Strategies were developed and implemented to overcome the identified gaps. In phase 2 (2014-2016) the impact of these developmental strategies was assessed.Results: A total of 65 interns, 30 residents, and 22 faculty members participated in phase I, while 71 interns participated in phase II. The reformation of orientation sessions, including practical exposure and content of sessions, opportunities to enhance hands-on experience and supervision in inpatient areas, operating rooms, supervision by fellows, supervision for hands-on procedures, career counseling, and mentorship, led to significant improvement in satisfaction. It was identified that the lack of hands-on opportunities can be overcome by surgical skills-based workshops. These reforms led to an overall rise in intern satisfaction (50% vs 75.4%, p=0.02).Conclusion: Periodic restructuring of an existing program helps to improve the work-based learning experience and overall satisfaction among interns. This not only maximizes learning but also eases interns into their postgraduate life and workload subsequently enabling them to become more competent and well-rounded health practitioners

    Re-structuring university hospital’s internship program using kern’s six-step model of Instructional design

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    Abstract Background: Internship is a phase of training wherein a graduate learns in the context of practice, acquiring skills under supervision so that he/she may become capable of functioning independently. We are reporting the process of curriculum restructuring for strengthening the Internship Program at this university hospital. Methodology: We used Kerns’ six-step model to evaluate and restructure the internship curriculum. Step 01: Problem Identification & General need assessment- Thorough literature review revealed Internship as the crucial year of training that needs to be fashioned around the competencies required to make good doctor

    Indiscriminate ingestion of entomopathogenic nematodes and their symbiotic bacteria by Aedes aegypti larvae: a novel strategy to control the vector of Chikungunya, dengue and yellow fever

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    Third and fourth instar larvae of Aedes aegypti actively ingested entomopathogenic nematodes (EPNs) and their symbiotic bacteria, resulting in larval mortality. All six EPN species evaluated in this study were pathogenic to Ae. aegypti but varied significantly in their virulence. Heterorhabditis bacteriophora and Steinernema carpocapsae were most virulent, H. megidis and S. kraussei showed the least virulence, whereas H. downesi and S. feltiae had intermediate virulence. Larval mortality was dose dependent for all EPN species. When using a dose of 100 infective juveniles (IJs) per larva, H. bacteriophora and S. carpocapsae caused 90%-100% mortality, whereas H. downesi and S. feltiae caused only 40%-60% mortality. Even when using 200 IJs/larva, H. megidis and S. kraussei caused a maximum of 30%-40% mortality. Some of the invasive EPNs were melanized, suggesting a strong humoral defense response by the Aedes larvae. The degree of melanization was quite variable; some EPNs were totally enveloped in a melanin sheath while others were partially coated with melanin. Melanization did not stop the EPN from multiplying and killing the Aedes larvae. IJs released from infected larvae would have the potential to infect healthy mosquito larvae. Also, both bacterial supernatant and bacterial cell suspension of Xenorhabdus nematophila caused >91% larval mortality after 48 h, whereas only the bacterial cell suspension of Photorhabdus laumondii was effective against the mosquito larvae. These data provides useful information on the potential use of EPNs and/or formulated bacterial cell suspensions in the control of the important urban and container-breeding mosquito, Ae. aegypti, and are a starting point for future simulated and actual field studies

    Metarhizium anisopliae blastospores are highly virulent to adult Aedes aegypti, an important arbovirus vector

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    BackgroundThe use of entomopathogenic fungi (EPF) for the control of adult mosquitoes is a promising alternative to synthetic insecticides. Previous studies have only evaluated conidiospores against adult mosquitoes. However, blastospores, which are highly virulent against mosquito larvae and pupae, could also be effective against adults.MethodsMetarhizium anisopliae (ESALQ 818 and LEF 2000) blastospores and conidia were first tested against adult Aedes aegypti by spraying insects with spore suspensions. Blastospores were then tested using an indirect contact bioassay, exposing mosquitoes to fungus-impregnated cloths. Virulence when using blastospores suspended in 20% sunflower oil was also investigated.ResultsFemale mosquitoes sprayed with blastospores or conidia at a concentration of 108 propagules ml−1 were highly susceptible to both types of spores, resulting in 100% mortality within 7 days. However, significant differences in virulence of the isolates and propagules became apparent at 107 spores ml−1, with ESALQ 818 blastospores being more virulent than LEF 2000 blastospores. ESALQ 818 blastospores were highly virulent when mosquitoes were exposed to black cotton cloths impregnated with blastospores shortly after preparing the suspensions, but virulence declined rapidly 12 h post-application. The addition of vegetable oil to blastospores helped maintain virulence for up to 48 h.ConclusionThe results showed that blastospores were more virulent to adult female Ae. aegypti than conidia when sprayed onto the insects or applied to black cloths. Vegetable oil helped maintain blastospore virulence. The results show that blastospores have potential for use in integrated vector management, although new formulations and drying techniques need to be investigated
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