162 research outputs found

    Effect of cultivation conditions on growth and antifungal activity of Mycena leptocephala

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    Growth and production of antifungal agent by Mycena leptocephala was investigated in different culture media composition at various initial pH and temperatures. Maximum growth and activity was observed at the initial pH of 5.5 and 25oC. No detectable growth and activity was observed at pH of 3.5 and 7.5. Growth of the fungus and antifungal activity were also very low at 37oC and 20oC. The organism grew better and culture extract showed higher level of antifungal activity when malt extract plus glucose were used as carbon source and yeast extract was used as nitrogen source. Meanwhile the lowest level of growth and antifungal activity were observed when starch was used as carbon source for growth of the fungus. Key Words: Culture conditions, basidiomycetes, bioactive compounds, carbon source, nitrogen source and temperature. African Journal of Biotechnology Vol.3(11) 2004: 606-60

    Measuring the impact of virtual reality on a serious game for improving oral presentation skill

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    Background and Objectives: Oral presentation is a key competence for success in the diverse work environments that academics need. It is recommended as part of a higher education curriculum. The role of technology in improving oral presentation skills and especially facilitating feedback, is significant. In particular, the combination of serious game and virtual reality is a new area of ​​research that is a modern alternative to traditional skills training. The interactive digital environment, real-time feedback, the realism of the learning scenario, the direct experience, and the persistence of the knowledge gained are some of the virtual reality opportunities for skills training. It should not be overlooked that insufficient budget, negative attitude of users about their physical and psychological condition after experiencing virtual reality, and poor technological design of virtual reality environments are also among the limitations of this technology. However, recent meta-analyzes confirm the influence of virtual reality in learning environments. Accordingly, the purpose of this study was to measure the impact of virtual reality on a serious game with the serious purpose of oral presentation training. Methods: We designed and developed an SG and conducted a quasi-experimental study with a post-test on 32 graduate students. The research question we sought to answer was “to what extent can VR impact the effectiveness of SGs in oral presentation training?” The authors also analyzed the cost-effectiveness of incorporating VR elements. The game focused on three key skills, eye contact, walking around while presenting, and time management. The experimental group played the game with the HTC Vive VR system and the control group played the same game with an HD display, a keyboard, and a mouse. In addition to that, we collected in-game data while players were playing the game. Mann-Whitney U test and Student's t-test were used to compare the two groups. Findings: Results revealed that VR elements did not have a significant impact on the demonstration of the players' eye contact skills but they increased players' tendency to walk around the virtual environment. Analysis of players’ performance regarding time management skills showed no significant difference between the two groups. Conclusion: It is concluded that even though playing the serious game with an HD display, a keyboard, and a mouse can be effective, turning the game into a VR experience would result in further improvement in the demonstration of some of the presentation key skills (walking around while presenting). However, creating a VR experience requires developers to spend more time and resources into developing the game. According to researchers, creating a VR SG for improving oral presentation skills allows for training to be done in the context that it occurs within. Moreover, the VR SG can be effectively used to overcome public presentation nerves. Also, due to the challenging economic situations outside the university and the need to benefit from communication skills and oral presentation, a serious game based on virtual reality can improve the indicators of oral presentation. Achieving this requires higher education attention to interactive technologies such as virtual reality.   ===================================================================================== COPYRIGHTS  ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

    Reactive direction control for a mobile robot: A locust-like control of escape direction emerges when a bilateral pair of model locust visual neurons are integrated

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    Locusts possess a bilateral pair of uniquely identifiable visual neurons that respond vigorously to the image of an approaching object. These neurons are called the lobula giant movement detectors (LGMDs). The locust LGMDs have been extensively studied and this has lead to the development of an LGMD model for use as an artificial collision detector in robotic applications. To date, robots have been equipped with only a single, central artificial LGMD sensor, and this triggers a non-directional stop or rotation when a potentially colliding object is detected. Clearly, for a robot to behave autonomously, it must react differently to stimuli approaching from different directions. In this study, we implement a bilateral pair of LGMD models in Khepera robots equipped with normal and panoramic cameras. We integrate the responses of these LGMD models using methodologies inspired by research on escape direction control in cockroaches. Using ‘randomised winner-take-all’ or ‘steering wheel’ algorithms for LGMD model integration, the khepera robots could escape an approaching threat in real time and with a similar distribution of escape directions as real locusts. We also found that by optimising these algorithms, we could use them to integrate the left and right DCMD responses of real jumping locusts offline and reproduce the actual escape directions that the locusts took in a particular trial. Our results significantly advance the development of an artificial collision detection and evasion system based on the locust LGMD by allowing it reactive control over robot behaviour. The success of this approach may also indicate some important areas to be pursued in future biological research

    Bayesian inference of population expansions in domestic bovines

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    The past population dynamics of four domestic and one wild species of bovine were estimated using Bayesian skyline plots, a coalescent Markov chain Monte Carlo method that does not require an assumed parametric model of demographic history. Four domestic species share a recent rapid population expansion not visible in the wild African buffalo (Syncerus caffer). The estimated timings of the expansions are consistent with the archaeological records of domestication

    A computational model of ureteral peristalsis and an investigation into ureteral reflux.

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    The aim of this study is to create a computational model of the human ureteral system that accurately replicates the peristaltic movement of the ureter for a variety of physiological and pathological functions. The objectives of this research are met using our in-house fluid-structural dynamics code (CgLes-Y code). A realistic peristaltic motion of the ureter is modelled using a novel piecewise linear force model. The urodynamic responses are investigated under two conditions of a healthy and a depressed contraction force. A ureteral pressure during the contraction shows a very good agreement with corresponding clinical data. The results also show a dependency of the wall shear stresses on the contraction velocity and it confirms the presence of a high shear stress at the proximal part of the ureter. Additionally, it is shown that an inefficient lumen contraction can increase the possibility of a continuous reflux during the propagation of peristalsis

    A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles

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    In recent years, there has been a dramatic increase in the use of unmanned aerial vehicles (UAVs), particularly for small UAVs, due to their affordable prices, ease of availability, and ease of operability. Existing and future applications of UAVs include remote surveillance and monitoring, relief operations, package delivery, and communication backhaul infrastructure. Additionally, UAVs are envisioned as an important component of 5G wireless technology and beyond. The unique application scenarios for UAVs necessitate accurate air-to-ground (AG) propagation channel models for designing and evaluating UAV communication links for control/non-payload as well as payload data transmissions. These AG propagation models have not been investigated in detail when compared to terrestrial propagation models. In this paper, a comprehensive survey is provided on available AG channel measurement campaigns, large and small scale fading channel models, their limitations, and future research directions for UAV communication scenarios

    ClpP protease activation results from the reorganization of the electrostatic interaction networks at the entrance pores

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    Bacterial ClpP is a highly conserved, cylindrical, self-compartmentalizing serine protease required for maintaining cellular proteostasis. Small molecule acyldepsipeptides (ADEPs) and activators of self-compartmentalized proteases 1 (ACP1s) cause dysregulation and activation of ClpP, leading to bacterial cell death, highlighting their potential use as novel antibiotics. Structural changes in Neisseria meningitidis and Escherichia co ClpP upon binding to novel ACP1 and ADEP analogs were probed by X-ray crystallography, methyl-TROSY NMR, and small angle X-ray scattering. ACP1 and ADEP induce distinct conformational changes in the ClpP structure. However, reorganization of electrostatic interaction networks at the ClpP entrance pores is necessary and sufficient for activation. Further activation is achieved by formation of ordered N-terminal axial loops and reduction in the structural heterogeneity of the ClpP cylinder. Activating mutations recapitulate the structural effects of small molecule activator binding. Our data, together with previous findings, provide a structural basis for a unified mechanism of compound-based ClpP activation2CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP306943/2015-8; 420567/2016-099999.004913/2015-092015/15822-1; 2012/01953-9; 2016/05019-0; 2012/50161-8Precision Medicine Initiative (PRiME) at the University of Toronto internal fellowship [PMRF2019-007]; Canadian Institutes of Health Research (CIHR) postdoctoral fellowshipCanadian Institutes of Health Research (CIHR); CNPq-Brazil fellowship [202192/2015-6]; Saskatchewan Health Research Foundation postdoctoral fellowship; Ontario Graduate Scholarship (OGS)Ontario Graduate Scholarship; Department of Biochemistry at the University of Toronto; Centre for Pharmaceutical Oncology (University of Toronto); CIHR Training Program in Protein Folding and Interaction Dynamics: Principles and Diseases fellowshipCanadian Institutes of Health Research (CIHR) [TGF-53910]; University of Toronto Fellowship from the Department of Biochemistry; OGS fellowship; NSERC PGS-D2 fellowship; CIHR Emerging Team Grants from the Institute of Infection and ImmunityCanadian Institutes of Health Research (CIHR) [XNE-86945]; CIHR Project grantCanadian Institutes of Health Research (CIHR) [PJT-148564]; Global Affairs Canada (Canada); CAPES (Brazil)CAPES [99999.004913/2015-09]; NSERCNatural Sciences and Engineering Research Council of Canada [RGPIN-2015-04877, DG-20234]; Canada Research Chairs ProgramCanada Research Chairs; CIHR new investigator programCanadian Institutes of Health Research (CIHR); FAPESPFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2015/15822-1, 2012/01953-9, 2016/05019-0, 2012/50161-8]; CNPqNational Council for Scientific and Technological Development (CNPq) [306943/2015-8, 420567/2016-0]; AbbVie [1097737]; BayerBayer AG [1097737]; Boehringer IngelheimBoehringer Ingelheim [1097737]; Genome Canada through Ontario Genomics Institute GrantGenome Canada [1097737, OGI-055]; GlaxoSmithKlineGlaxoSmithKline [1097737]; JanssenJohnson & Johnson USAJanssen Biotech Inc [1097737]; Lilly CanadaEli Lilly [1097737]; MerckMerck & Company [1097737]; Novartis Research Foundation [1097737]; Ontario Ministry of Economic Development and Innovation [1097737]; PfizerPfizer [1097737]; TakedaTakeda Pharmaceutical Company Ltd [1097737]; Wellcome Trust GrantWellcome Trust [1097737, 092809/Z/10/Z]; Canada Foundation for InnovationCanada Foundation for Innovation; NSERCNatural Sciences and Engineering Research Council of Canada; University of Saskatchewan; Government of Saskatchewan; Western Economic Diversification Canada; National Research Council Canada; CIHRCanadian Institutes of Health Research (CIHR

    Path analysis of the relationship between optimism, humor, affectivity, and marital satisfaction among infertile couples

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    Marital satisfaction is an important factor for establishing a family relationship, feeling satisfied, and living happily together. The aim of the present study was to investigate the relationship between optimism, humor, positive and negative affect, and marital satisfaction among infertile couples. The sample comprised 80 infertile Iranian couples (n = 160) who visited infertility clinics. Participants completed a series of Persian versions of psychometric scales related to optimism (Attributional Style Questionnaire), humor (Humor Styles Questionnaire), marital satisfaction (Enrich Marital Satisfaction Questionnaire), positive affect (PA) and negative affect (NA) (Positive and Negative Affect Schedule). The obtained result of Smart PLS statistical analysis confirmed the significant positive correlation between optimism and humor with marital satisfaction and high PA and low NA. Moreover, the findings also provided an adequate fit of the model. The findings demonstrated that infertile couples high in optimism and humor have higher levels of marital satisfaction and high PA and low PA. Based on the study’s findings, interventions for facilitating optimism and humor among infertile couples are discussed

    DMRN+16: Digital Music Research Network One-day Workshop 2021

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    DMRN+16: Digital Music Research Network One-day Workshop 2021 Queen Mary University of London Tuesday 21st December 2021 Keynote speakers Keynote 1. Prof. Sophie Scott -Director, Institute of Cognitive Neuroscience, UCL. Title: "Sound on the brain - insights from functional neuroimaging and neuroanatomy" Abstract In this talk I will use functional imaging and models of primate neuroanatomy to explore how sound is processed in the human brain. I will demonstrate that sound is represented cortically in different parallel streams. I will expand this to show how this can impact on the concept of auditory perception, which arguably incorporates multiple kinds of distinct perceptual processes. I will address the roles that subcortical processes play in this, and also the contributions from hemispheric asymmetries. Keynote 2: Prof. Gus Xia - Assistant Professor at NYU Shanghai Title: "Learning interpretable music representations: from human stupidity to artificial intelligence" Abstract Gus has been leading the Music X Lab in developing intelligent systems that help people better compose and learn music. In this talk, he will show us the importance of music representation for both humans and machines, and how to learn better music representations via the design of inductive bias. Once we got interpretable music representations, the potential applications are limitless

    COVID-19-related strokes in adults below 55Â years of age: a case series

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    Background: Coronavirus infection is a novel respiratory disease affecting people across the world. Although the majority of patients present with fever, dyspnea, cough, or myalgia, various signs and symptoms have been reported for this disease. Recently, neurological symptoms have been noticed in patients with COVID-19 with unknown etiology. However, the occurrence of strokes in young and middle aged patients with COVID-19 is not fully explained. Methods: In this series, six patients younger than 55 years of age with diagnosis of stroke and a confirmed diagnosis of COVID-19 were evaluated for symptoms, lab data, imaging findings, and outcomes from March 2020 to the end of April 2020 from all stroke cases in a tertiary academic hospital. Patients older than 55 and all others who had evidence of cardiac abnormalities (arrhythmia/valvular) were excluded. Results: Fever, myalgia, cough, and dyspnea were the most common clinical symptoms noted in 66.66 (4/6), 66.66 (4/6), 50 (3/6), and 50 (3/6) of the patients, respectively. The mean ± standard deviation (SD) of National Institutes of Health Stroke Scale (NIHSS) for the patient was 10.16 ± 7.13 (ranged 5�24). The most involved area was middle cerebral artery (MCA) (five in MCA versus one in basal ganglia) and the majority of our patients had a low lung involvement score (mean ± SD: 13.16 ± 6.49 out of 24). Finally, one patient was deceased and rest discharged. Conclusion: Stroke may be unrelated to age and the extent of lung involvement. However, different factors may play roles in co-occurrence of stroke and COVID-19 and its outcome. Future studies with long-term follow-up and more cases are needed to assess prognostic factors. © 2020, Fondazione Società Italiana di Neurologia
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