568 research outputs found

    A Faster Triphosphorylation Ribozyme.

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    In support of the RNA world hypothesis, previous studies identified trimetaphosphate (Tmp) as a plausible energy source for RNA world organisms. In one of these studies, catalytic RNAs (ribozymes) that catalyze the triphosphorylation of RNA 5'-hydroxyl groups using Tmp were obtained by in vitro selection. One ribozyme (TPR1) was analyzed in more detail. TPR1 catalyzes the triphosphorylation reaction to a rate of 0.013 min-1 under selection conditions (50 mM Tmp, 100 mM MgCl2, 22°C). To identify a triphosphorylation ribozyme that catalyzes faster triphosphorylation, and possibly learn about its secondary structure TPR1 was subjected to a doped selection. The resulting ribozyme, TPR1e, contains seven mutations relative to TPR1, displays a previously unidentified duplex that constrains the ribozyme's structure, and reacts at a 24-fold faster rate than the parent ribozyme. Under optimal conditions (150 mM Tmp, 650 mM MgCl2, 40°C), the triphosphorylation rate of TRP1e reaches 6.8 min-1

    Speech Act Classification in Donald Trump’s Policy-Campaign of The Upcoming Presidential Election Usa 2017

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    Abstrak Penelitian ini membahas mengenai klasifikasi tindak tutur pada kampanye kebijakan Donald Trump pada pemilihan presiden Amerika Serikat 2017. Disinyalir Donald Trump menghimpun kekuatan dan pidatonya mengandung rasisme. Namun di sisi lain, pidatonya dapat mempengaruhi orang lain. Penelitian ini akan terfokus pada dua rumusan masalah; (1) Apa saja klasifikasi tindak tutur yang muncul dalam kampanye Donald Trump? dan (2) Bagaimana Donald Trump membangun kampanyenya dengan menuturkan kata-kata rasis? Maka dari itu, untuk menyelesaikan penelitian ini, metode deskriptif kualitatif diterapkan dengan menggunakan metode observasi tidak langsung, dikarenakan objek media yang digunakan adalah video. Penelitian ini menerapkan teori analisis wacana kritis dikombinasikan dengan pragmatik dalam menganalisa data. Hasil penelitian menunjukkan bahwa Donald Trump lebih sering menggunakan tindak tutur deklaratif dan direktif untuk menekankan kekuatannya dalam kampanye. Selain itu, kampanyenya juga memiliki kecenderungan rasisme. Kata kunci: kampanye, Donald Trump, rasisme   Abstract This study is about the speech act classification in Donald Trump’s policy-campaign of the upcoming presidential election USA 2017. It is found that Donald trump is gaining power, and his speech includes racism. But on the other hand, his speech might influence other people. The center of this study is focusing on two problems; (1) What are the speech acts classification appeared in Donald Trump’s campaign? and (2) How did he build his campaign by showing remarks of racism? To finish this study, the method applied was descriptive qualitative using observation non-participatory technique since it is a video. In this study, the theory of Critical Discourse Analysis and pragmatics point of view were applied to analyse the data. The finding showed that declarative and directive as the speech act classification were mostly used by Donald Trump to emphasize his power. Besides those utterances, there were also remarks of speech that showed Donald Trump had tendency in racism.   Keywords: campaign, Donald Trump, racis

    A versatile high-performance visual fiducial marker detection system with scalable identity encoding

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    Fiducial markers have a wide field of applications in robotics, ranging from external localisation of single robots or robotic swarms, over self-localisation in marker-augmented environments, to simplifying perception by tagging objects in a robot’s surrounding. We propose a new family of circular markers allowing for a computationally efficient detection, identification and full 3D position estimation. A key concept of our system is the separation of the detection and identification steps, where the first step is based on a computationally efficient circular marker detection, and the identification step is based on an open-ended ‘Necklace code’, which allows for a theoretically infinite number of individually identifiable markers. The experimental evaluation of the system on a real robot indicates that while the proposed algorithm achieves similar accuracy to other state-of-the-art methods, it is faster by two orders of magnitude and it can detect markers from longer distances

    Local Communication Protocols for Learning Complex Swarm Behaviors with Deep Reinforcement Learning

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    Swarm systems constitute a challenging problem for reinforcement learning (RL) as the algorithm needs to learn decentralized control policies that can cope with limited local sensing and communication abilities of the agents. While it is often difficult to directly define the behavior of the agents, simple communication protocols can be defined more easily using prior knowledge about the given task. In this paper, we propose a number of simple communication protocols that can be exploited by deep reinforcement learning to find decentralized control policies in a multi-robot swarm environment. The protocols are based on histograms that encode the local neighborhood relations of the agents and can also transmit task-specific information, such as the shortest distance and direction to a desired target. In our framework, we use an adaptation of Trust Region Policy Optimization to learn complex collaborative tasks, such as formation building and building a communication link. We evaluate our findings in a simulated 2D-physics environment, and compare the implications of different communication protocols.Comment: 13 pages, 4 figures, version 2, accepted at ANTS 201

    Development of IR-based short-range communication techniques for swarm robot applications

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    This paper proposes several designs for a reliable infra-red based communication techniques for swarm robotic applications. The communication system was deployed on an autonomous miniature mobile robot (AMiR), a swarm robotic platform developed earlier. In swarm applications, all participating robots must be able to communicate and share data. Hence a suitable communication medium and a reliable technique are required. This work uses infrared radiation for transmission of swarm robots messages. Infrared transmission methods such as amplitude and frequency modulations will be presented along with experimental results. Finally the effects of the modulation techniques and other parameters on collective behavior of swarm robots will be analyzed

    Open hardware and software robotics competition for additional engagement in ECE students - the Robot@Factory lite case study

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    Throughout this paper, a competition created to enable an inter-connection between the academic and industrial paradigms is presented, using Open Hardware and Software. This competition is called Robot at Factory Lite and serves as a case study as an additional enrollment for students to apply knowledge in the fields of programming, perception, motion planning, task planning, autonomous robotic, among others.This work is financed by National Funds through the Portuguese funding agency, FCT- Fundação para a Ciência e a Tecnologia, with in project UIDB/50014/2020info:eu-repo/semantics/publishedVersio

    An efficient visual fiducial localisation system

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    With use cases that range from external localisation of single robots or robotic swarms to self-localisation in marker-augmented environments and simplifying perception by tagging objects in a robot's surrounding, fiducial markers have a wide field of application in the robotic world. We propose a new family of circular markers which allow for both computationally efficient detection, tracking and identification and full 6D position estimation. At the core of the proposed approach lies the separation of the detection and identification steps, with the former using computationally efficient circular marker detection and the latter utilising an open-ended `necklace encoding', allowing scalability to a large number of individual markers. While the proposed algorithm achieves similar accuracy to other state-of-the-art methods, its experimental evaluation in realistic conditions demonstrates that it can detect markers from larger distances while being up to two orders of magnitude faster than other state-of-the-art fiducial marker detection methods. In addition, the entire system is available as an open-source package at \url{https://github.com/LCAS/whycon}

    Immediate early protein of equid herpesvirus type 1 as a target for cytotoxic T-lymphocytes in the thoroughbred horse

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    Cytotoxic T-lymphocytes (CTLs) are associated with protective immunity against disease caused by equid herpesvirus type 1 (EHV-1). However, the EHV-1 target proteins for CTLs are poorly defined. This limits the development of vaccine candidates designed to stimulate strong CTL immunity. Here, classical CTL assays using lymphocytes from horses of three defined MHC class I types that experienced natural infection with EHV-1 and a modified vaccinia virus construct containing an EHV-1 gene encoding the immediate-early (IE) protein are reported. Horses homozygous for the equine leukocyte antigen (ELA)-A2 haplotype, but not the ELA-A5 haplotype, produced MHC-restricted CTL responses against the IE protein. Previously, horses homozygous for the ELA-A3 haplotype also mounted CTL responses against the IE protein. Both haplotypes are common in major horse breeds, including the Thoroughbred. Thus, the IE protein is an attractive candidate molecule for future studies of T-cell immunity to EHV-1 in the horse

    CD4 T Cell Immunity Is Critical for the Control of Simian Varicella Virus Infection in a Nonhuman Primate Model of VZV Infection

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    Primary infection with varicella zoster virus (VZV) results in varicella (more commonly known as chickenpox) after which VZV establishes latency in sensory ganglia. VZV can reactivate to cause herpes zoster (shingles), a debilitating disease that affects one million individuals in the US alone annually. Current vaccines against varicella (Varivax) and herpes zoster (Zostavax) are not 100% efficacious. Specifically, studies have shown that 1 dose of varivax can lead to breakthrough varicella, albeit rarely, in children and a 2-dose regimen is now recommended. Similarly, although Zostavax results in a 50% reduction in HZ cases, a significant number of recipients remain at risk. To design more efficacious vaccines, we need a better understanding of the immune response to VZV. Clinical observations suggest that T cell immunity plays a more critical role in the protection against VZV primary infection and reactivation. However, no studies to date have directly tested this hypothesis due to the scarcity of animal models that recapitulate the immune response to VZV. We have recently shown that SVV infection of rhesus macaques models the hallmarks of primary VZV infection in children. In this study, we used this model to experimentally determine the role of CD4, CD8 and B cell responses in the resolution of primary SVV infection in unvaccinated animals. Data presented in this manuscript show that while CD20 depletion leads to a significant delay and decrease in the antibody response to SVV, loss of B cells does not alter the severity of varicella or the kinetics/magnitude of the T cell response. Loss of CD8 T cells resulted in slightly higher viral loads and prolonged viremia. In contrast, CD4 depletion led to higher viral loads, prolonged viremia and disseminated varicella. CD4 depleted animals also had delayed and reduced antibody and CD8 T cell responses. These results are similar to clinical observations that children with agammaglobulinemia have uncomplicated varicella whereas children with T cell deficiencies are at increased risk of progressive varicella with significant complications. Moreover, our studies indicate that CD4 T cell responses to SVV play a more critical role than antibody or CD8 T cell responses in the control of primary SVV infection and suggest that one potential mechanism for enhancing the efficacy of VZV vaccines is by eliciting robust CD4 T cell responses
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