1,735 research outputs found

    Impact of methionine nutrition on the leaf proteome of Lupinus angustifolius L. and Vicia faba L.

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    Grain legumes possess a gernerally favourable seed protein amino acid composition but low contents of sulfur amino acids decrease their nutrient value. To enhance the methionie content of local grain legumes by plant breeding, phenotypical attributes for high methionine contents are required for the selection process

    Combining Passive and Active Ultrasonic Stress Wave Monitoring Techniques: Opportunities for Condition Evaluation of Concrete Structures

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    Concrete structures are invaluable assets to a society and managing them efficiently and effectively can be supported by information gathered through structural health monitoring (SHM). In this paper, a combined approach based on passive, i.e., acoustic emission (AE), and active, i.e., ultrasonic stress wave (USW) monitoring techniques for application to concrete structures is proposed and evaluated. While AE and USW are based on the same underlying physics, i.e., wave motion in solids, they differ fundamentally with respect to the nature of the source. For the former, external stimuli such as mechanical loads or temperature cause the rapid release of energy from initially unknown locations. As a result, AE events are unique and cannot be repeated. For the latter, a known source at a known location is employed at a specified time. This approach is thus controlled and repeatable. It is argued that a combination of these two techniques has the potential to provide a more comprehensive picture of ongoing fracture processes, damage progression, as well as slowly occurring aging and degradation mechanisms. This combined approach does thus promise new opportunities to support condition assessment of concrete structures. After providing an overview and comparison of the two techniques, results, and observations from a full-scale laboratory experiment and an in-service bridge monitoring study are discussed to demonstrate the promise of the proposed combined monitoring approach. Finally, suggestions for further work are presented

    Early Detection of Structural Damage in UHPFRC Structures through the Combination of Acoustic Emission and ultrasonic stress wave monitoring

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    Ultra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC) offers several advantages compared to concrete, notably due to the strain hardening behavior under tensile actions. Structures made of this composite material are lightweight and highly durable, thanks to the UHPFRC waterproofing quality. Nonetheless, the tensile behavior leads to a different cracking pattern than conventional concrete and is not fully understood yet. This paper presents a combined approach using both passive ultrasonic (US) stress wave (or acoustic emission) and active US stress wave monitoring to localize and quantify damage progression in a full-scale UHPFRC beam during experimental load testing. The proposed monitoring approach involves 24 US transducers that are embedded randomly throughout a 4.2meter-long laboratory UHPFRC T-beam. Continuous monitoring enabled accurate localization of US stress sources caused by loading-induced cracking as well as from pulses generated by the embedded US transducers. This study shows that it is possible to predict the location and shape of the macro-crack that is linked to structural failure early on, i.e., just after the end of the elastic domain. This combined approach opens new possibilities to monitor the structural behavior and detect damage on UHPFRC structures before they affect the structural behavior in terms of deflection and strain

    Combined Passive and Active Ultrasonic Stress Wave Monitoring of Concrete Structures: An Overview of Data Analysis Techniques and Their Applications and Limitations

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    Combined passive ultrasonic (US) stress wave [better known as acoustic emission (AE)] and active US stress wave monitoring has been shown to provide a more holistic picture of ongoing fracture processes, damage progression, as well as slowly occurring aging and degradation mechanisms in concrete structures. Traditionally, different data analysis techniques have been used to analyze the data generated from these two monitoring techniques. For passive US stress wave monitoring, waveform amplitudes, hit rates, source localization, and b-value analysis, among others, have been used to detect and locate cracking. On the other hand, amplitude tracking, magnitude squared coherence (MSC), and coda wave interferometry (CWI) are examples of analyses that have been employed for active US stress wave monitoring. In this paper, we explore some of these data analysis techniques and show where their respective applications and limitations might be. After providing an overview of the monitoring approach and the different data analysis techniques, results and observations from selected laboratory experiments are discussed. Finally, suggestions for further work are proposed

    Medical Age Assessment of Juvenile Migrants

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    An important aspect of the reception of unaccompanied children in migration is the question of their age. As these young people frequently arrive without reliable documents, their age might be called into question. This puts into focus age assessment, the attempt by authorities to estimate the (chronological) age of a person, in the absence of reliable documentation regarding age. As there is no such simple technique for humans as counting the age rings of trees, any existing age assessment approach is subject to discussions and possibly even disagreements. Medical methods for age determination are usually the ones considered as more problematical for a number of reasons. The most important class of medical methods are those based on the observation of age markers, i.e. somatic indicators that change in a given way with age. As a large number of scientific studies has investigated this relationship in detail, it is assumed that this method allows for reliable and reproducible conclusion about the true age of a person. This ambitious claim is not unchallenged. In addition to doubts about the real precision of medical methods, there are also health and ethical issues. On the other hand, the high potential to establish age estimation on objective criteria, thereby reducing the dependence on individual expert opinion, has raised high expectations and attention on age markers. The current report aims to analyse to what extent these expectations can be met.JRC.E.6-Demography, Migration and Governanc

    MIMo: A Multi-Modal Infant Model for Studying Cognitive Development

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    Human intelligence and human consciousness emerge gradually during the process of cognitive development. Understanding this development is an essential aspect of understanding the human mind and may facilitate the construction of artificial minds with similar properties. Importantly, human cognitive development relies on embodied interactions with the physical and social environment, which is perceived via complementary sensory modalities. These interactions allow the developing mind to probe the causal structure of the world. This is in stark contrast to common machine learning approaches, e.g., for large language models, which are merely passively ``digesting'' large amounts of training data, but are not in control of their sensory inputs. However, computational modeling of the kind of self-determined embodied interactions that lead to human intelligence and consciousness is a formidable challenge. Here we present MIMo, an open-source multi-modal infant model for studying early cognitive development through computer simulations. MIMo's body is modeled after an 18-month-old child with detailed five-fingered hands. MIMo perceives its surroundings via binocular vision, a vestibular system, proprioception, and touch perception through a full-body virtual skin, while two different actuation models allow control of his body. We describe the design and interfaces of MIMo and provide examples illustrating its use. All code is available at https://github.com/trieschlab/MIMo .Comment: 11 pages, 8 figures. Submitted to IEEE Transactions on Congnitive and Developmental Systems (TCDS

    Early detection of structural damage in UHPFRC structures through the combination of acoustic emission and ultrasonic stress wave monitoring

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    peer reviewedUltra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC) offers several advantages compared to concrete, notably due to the strain hardening behavior under tensile actions. Structures made of this composite material are lightweight and highly durable, thanks to the UHPFRC waterproofing quality. Nonetheless, the tensile behavior leads to a different cracking pattern than conventional concrete and is not fully understood yet. This paper presents a combined approach using both passive ultrasonic (US) stress wave (or acoustic emission) and active US stress wave monitoring to localize and quantify damage progression in a full-scale UHPFRC beam during experimental load testing. The proposed monitoring approach involves 24 US transducers that are embedded randomly throughout a 4.2meter-long laboratory UHPFRC T-beam. Continuous monitoring enabled accurate localization of US stress sources caused by loading-induced cracking as well as from pulses generated by the embedded US transducers. This study shows that it is possible to predict the location and shape of the macro-crack that is linked to structural failure early on, i.e., just after the end of the elastic domain. This combined approach opens new possibilities to monitor the structural behavior and detect damage on UHPFRC structures before they affect the structural behavior in terms of deflection and strain

    Effective Pure States for Bulk Quantum Computation

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    In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure expectation values of certain observables with limited sensitivity. The initial state of each computer in the ensemble is known but not pure. Methods for obtaining effective pure input states by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) and Cory et al. (spatial averaging) for the case of quantum computation with nuclear magnetic resonance. We give a different technique called temporal averaging. This method is based on classical randomization, requires no ancilla qubits and can be implemented in nuclear magnetic resonance without using gradient fields. We introduce several temporal averaging algorithms suitable for both high temperature and low temperature bulk quantum computing and analyze the signal to noise behavior of each.Comment: 24 pages in LaTex, 14 figures, the paper is also avalaible at http://qso.lanl.gov/qc

    Behavioral Responses to Uncertainty in Weight-Restored Anorexia Nervosa – Preliminary Results

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    Impaired decision-making under conditions of uncertainty seems to contribute to theexpression and maintenance of anorexia nervosa (AN), but it is not clear whether thisimpairment is a disease state that would remit with treatment, or a persisting trait inpatients with AN. To examine this question, a longitudinal study was conducted in12 female inpatients with AN (age M = 22.2, SE = 1.36), before (Time-1) and afterreaching a body mass index of >17.5 kg/m2 (Time-2). Intolerance of uncertainty (IU)was assessed via a decision-making task, the wheel of fortune (WOF). Weight gain atTime-2 was accompanied with significant changes in uncertainty-related performancecompared to Time-1 [(Time Uncertainty), p < 0.05]. At Time-1, reaction times (RTs)varied in function of uncertainty, while at Time-2, uncertainty did not modulate RTs.These findings support a change in decision-making under uncertainty with successfulweight-rehabilitation in AN. While IU was present in underweight patients, it becamenon-significant after weight restoration

    Complete quantum teleportation using nuclear magnetic resonance

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    Quantum mechanics provides spectacular new information processing abilities (Bennett 1995, Preskill 1998). One of the most unexpected is a procedure called quantum teleportation (Bennett et al 1993) that allows the quantum state of a system to be transported from one location to another, without moving through the intervening space. Partial implementations of teleportation (Bouwmeester et al 1997, Boschi et al 1998) over macroscopic distances have been achieved using optical systems, but omit the final stage of the teleportation procedure. Here we report an experimental implementation of the full quantum teleportation operation over inter-atomic distances using liquid state nuclear magnetic resonance (NMR). The inclusion of the final stage enables for the first time a teleportation implementation which may be used as a subroutine in larger quantum computations, or for quantum communication. Our experiment also demonstrates the use of quantum process tomography, a procedure to completely characterize the dynamics of a quantum system. Finally, we demonstrate a controlled exploitation of decoherence as a tool to assist in the performance of an experiment.Comment: 15 pages, 2 figures. Minor differences between this and the published versio
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