158 research outputs found

    Space and Time in Perceptual Causality

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    Inferring causality is a fundamental feature of human cognition that allows us to theorize about and predict future states of the world. Michotte suggested that humans automatically perceive causality based on certain perceptual features of events. However, individual differences in judgments of perceptual causality cast doubt on Michotte's view. To gain insights in the neural basis of individual difference in the perception of causality, our participants judged causal relationships in animations of a blue ball colliding with a red ball (a launching event) while fMRI-data were acquired. Spatial continuity and temporal contiguity were varied parametrically in these stimuli. We did not find consistent brain activation differences between trials judged as caused and those judged as non-caused, making it unlikely that humans have universal instantiation of perceptual causality in the brain. However, participants were slower to respond to and showed greater neural activity for violations of causality, suggesting that humans are biased to expect causal relationships when moving objects appear to interact. Our participants demonstrated considerable individual differences in their sensitivity to spatial and temporal characteristics in perceiving causality. These qualitative differences in sensitivity to time or space in perceiving causality were instantiated in individual differences in activation of the left basal ganglia or right parietal lobe, respectively. Thus, the perception that the movement of one object causes the movement of another is triggered by elemental spatial and temporal sensitivities, which themselves are instantiated in specific distinct neural networks

    Digital Supply Chain Twins in Practice: Outlining the Technological and Organizational Requirements for Successful Implementation

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    Digital supply chain twins (DSCT) are often considered as one of the most promising technologies to efficiently and proactively manage increasingly complex international logistics networks in the future. Despite the recognition of the potential, the concrete development of digital twins of logistics networks is still in earlier stages in practice. Most twins focus on mapping digital twins of logistics assets or sites rather than elevating the technology to a network level. Building on the Nominal Group Technique among 18 logistics managers this study seeks to investigate the requirements of successful DSCT implementation at a network level. The study shows that while there are various technological requirements that need to be created for the development, it is also DSCT-specific intra- and inter-organizational requirements that influence the successful implementation and use of DSCTs

    Experiencias de laboratorio de Física Nuclear en aislamiento

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    Durante el primer cuatrimestre de 2020 se restringió en todo el territorio nacional, el ingreso de docentesy estudiantes a los edificios universitarios en el marco del Aislamiento Social Preventivo y Obligatorio“ASPO”. Ante esta situación, el Laboratorio de Transductores y Física nuclear (LTFN) de la Facultad deCiencias Exactas y Tecnología de la Universidad Nacional de Tucumán, avanzó con la virtualización desus experiencias de laboratorio para su asignatura “Física Nuclear” con el objeto de que los estudiantes nopierdan las vivencias propias de las experiencias reales. Las virtualizaciones fueron desarrolladasmediante herramientas de fácil acceso y, en lo posible, de costo cero. Herramientas tan populares comoMicrosoft Power Point y GeoGebra, fueron utilizadas de manera novedosa para crear instrumentaciónvirtual de medición. Se logró concretar el dictado de la asignatura sin sacrificar contenidos ni cargaexperimental a pesar de la situación particular que vive el mundo por la pandemia de COVID 19. Seespera que estas implementaciones posibiliten, en un futuro cercano, la extensión de esta oferta formativamás allá de este aislamiento y de los límites provinciales y nacionales, como así también, su cursado ensituaciones especiales con riesgo radiológico nulo pero con una considerable carga experimental.Fil: Carrillo, Miguel Angel. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física; ArgentinaFil: Straube, Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física; Argentin

    Spatial positioning of EB family proteins at microtubule tips involves distinct nucleotide-dependent binding properties

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    EB proteins track the ends of growing microtubules and regulate microtubule dynamics both directly and by acting as the hub of the tip-tracking network. Mammalian cells express cell type-specific combinations of three EB proteins with different cellular roles. Here we reconstitute EB1, EB2 and EB3 tip tracking in vitro. We find that all three EBs show rapid exchange at the microtubule tip and that their signal correlates to the microtubule assembly rate. However, the three signals differ in their maxima and the position from the microtubule tip. Using microtubules built with nucleotide analogues and site-directed mutagenesis, we show that EB2 prefers binding to microtubule lattices containing a 1:1 mixture of different nucleotides and its distinct binding specificity is conferred by amino acid substitutions at the right-hand side interface of the EB microtubule-binding domain with tubulin. Our data are consistent with the model that all three EB paralogs sense the nucleotide state of both β-tubulins flanking their binding site. Their different profile of preferred binding sites contributes to occupying spatially distinct domains at the temporally evolving microtubule tip structure

    The Role of Gamma Oscillations During Integration of Metaphoric Gestures and Abstract Speech

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    Metaphoric (MP) co-speech gestures are commonly used during daily communication. They communicate about abstract information by referring to gestures that are clearly concrete (e.g., raising a hand for “the level of the football game is high”). To understand MP co-speech gestures, a multisensory integration at semantic level is necessary between abstract speech and concrete gestures. While semantic gesture-speech integration has been extensively investigated using functional magnetic resonance imaging, evidence from electroencephalography (EEG) is rare. In the current study, we set out an EEG experiment, investigating the processing of MP vs. iconic (IC) co-speech gestures in different contexts, to reveal the oscillatory signature of MP gesture integration. German participants (n = 20) viewed video clips with an actor performing both types of gestures, accompanied by either comprehensible German or incomprehensible Russian (R) speech, or speaking German sentences without any gestures. Time-frequency analysis of the EEG data showed that, when gestures were accompanied by comprehensible German speech, MP gestures elicited decreased gamma band power (50–70 Hz) between 500 and 700 ms in the parietal electrodes when compared to IC gestures, and the source of this effect was localized to the right middle temporal gyrus. This difference is likely to reflect integration processes, as it was reduced in the R language and no-gesture conditions. Our findings provide the first empirical evidence suggesting the functional relationship between gamma band oscillations and higher-level semantic processes in a multisensory setting

    Digital Supply Chain Twins—Conceptual Clarification, Use Cases and Benefits

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    Background: Digital supply chain twins (DSCT) are gaining increased attention in academia and practice as they emerge as one of the most important trends in logistics and supply chain management (LSCM). Still, there seems to be no common understanding of the term in scientific literature. Moreover, the broad field of LSCM allows for a multitude of feasible application areas and use cases, yet there exists no conclusive list of them as to date. Methods: This study builds upon a systematic literature review of 66 DSCT articles to identify application areas of DSCT in LSCM as well as specific use cases and their respective intended benefits. Results: To start with, the study derives a unified definition of DSCTs, including possible scopes of applications. Afterwards, five application areas of DSCT in LSCM are synthesized as well as 14 individual use cases and their respective intended benefits. Conclusions: The study leads towards a conceptual clarification of DSCT that is of importance for research and practice alike. For managers it additionally provides up-to-date use cases to guide DSCT applications in practice

    Support Vector Machine Analysis of Functional Magnetic Resonance Imaging of Interoception Does Not Reliably Predict Individual Outcomes of Cognitive Behavioral Therapy in Panic Disorder with Agoraphobia

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    Background: The approach to apply multivariate pattern analyses based on neuro imaging data for outcome prediction holds out the prospect to improve therapeutic decisions in mental disorders. Patients suffering from panic disorder with agoraphobia (PD/AG) often exhibit an increased perception of bodily sensations. The purpose of this investigation was to assess whether multivariate classification applied to a functional magnetic resonance imaging (fMRI) interoception paradigm can predict individual responses to cognitive behavioral therapy (CBT) in PD/AG. Methods: This analysis is based on pretreatment fMRI data during an interoceptive challenge from a multicenter trial of the German PANIC-NET. Patients with DSM-IV PD/AG were dichotomized as responders (n = 30) or non-responders (n = 29) based on the primary outcome (Hamilton Anxiety Scale Reduction ≥50%) after 6 weeks of CBT (2 h/week). fMRI parametric maps were used as features for response classification with linear support vector machines (SVM) with or without automated feature selection. Predictive accuracies were assessed using cross validation and permutation testing. The influence of methodological parameters and the predictive ability for specific interoception-related symptom reduction were further evaluated. Results: SVM did not reach sufficient overall predictive accuracies (38.0–54.2%) for anxiety reduction in the primary outcome. In the exploratory analyses, better accuracies (66.7%) were achieved for predicting interoception-specific symptom relief as an alternative outcome domain. Subtle information regarding this alternative response criterion but not the primary outcome was revealed by post hoc univariate comparisons. Conclusion: In contrast to reports on other neurofunctional probes, SVM based on an interoception paradigm was not able to reliably predict individual response to CBT. Results speak against the clinical applicability of this technique

    Franz-Keldysh effect in epitaxial ZnO thin films

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    Photoconductance spectroscopy has been studied in epitaxial ZnO thin films with different thicknesses that range between 136 and 21 nm. We report a systematic decrease in photoconductivity and a red shift in band edge photoconductance spectra when the thickness is reduced. For thinner films, it is found that the effective energy gap value diminishes. By time dependent photoconductivity measurements, we found an enhanced contribution of the slow relaxation times for thicker films. These effects are interpreted in terms of a band-bending contribution where the Franz-Keldysh effect and the polarization of ZnO play a major role in thinner films.Fil: Bridoux, German. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Ferreyra, Jorge Mario. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Guimpel, Julio Juan. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nieva, Gladys Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Figueroa, Carlos Alejandro. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Straube, Benjamin. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Pérez, Silvia Inés. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentin

    The effect of self‐generated versus externally generated actions on timing, duration, and amplitude of blood oxygen level dependent response for visual feedback processing

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    It has been widely assumed that internal forward models use efference copies to create predictions about the sensory consequences of our own actions. While these predictions have frequently been associated with a reduced blood oxygen level dependent (BOLD) response in sensory cortices, the timing and duration of the hemodynamic response for the processing of video feedback of self-generated (active) versus externally generated (passive) movements is poorly understood. In the present study, we tested the hypothesis that predictive mechanisms for self-generated actions lead to early and shorter neural processing compared with externally generated movements. We investigated active and passive movements using a custom-made fMRI-compatible movement device. Visual video feedback of the active and passive movements was presented in real time or with variable delays. Participants had to judge whether the feedback was delayed. Timing and duration of BOLD impulse response was calculated using a first (temporal derivative [TD]) and second-order (dispersion derivative [DD]) Taylor approximation. Our reanalysis confirmed our previous finding of reduced BOLD response for active compared to passive movements. Moreover, we found positive effects of the TD and DD in the supplementary motor area, cerebellum, visual cortices, and subcortical structures, indicating earlier and shorter hemodynamic responses for active compared to passive movements. Furthermore, earlier activation in the putamen for active compared to passive conditions was associated with reduced delay detection performance. These findings indicate that efference copy-based predictive mechanisms enable earlier processing of action feedback, which might have reduced the ability to detect short delays between action and feedback

    Different contributions of efferent and reafferent feedback to sensorimotor temporal recalibration

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    Abstract: Adaptation to delays between actions and sensory feedback is important for efficiently interacting with our environment. Adaptation may rely on predictions of action-feedback pairing (motor-sensory component), or predictions of tactile-proprioceptive sensation from the action and sensory feedback of the action (inter-sensory component). Reliability of temporal information might differ across sensory feedback modalities (e.g. auditory or visual), which in turn influences adaptation. Here, we investigated the role of motor-sensory and inter-sensory components on sensorimotor temporal recalibration for motor-auditory (button press-tone) and motor-visual (button press-Gabor patch) events. In the adaptation phase of the experiment, action-feedback pairs were presented with systematic temporal delays (0 ms or 150 ms). In the subsequent test phase, audio/visual feedback of the action were presented with variable delays. The participants were then asked whether they detected a delay. To disentangle motor-sensory from inter-sensory component, we varied movements (active button press or passive depression of button) at adaptation and test. Our results suggest that motor-auditory recalibration is mainly driven by the motor-sensory component, whereas motor-visual recalibration is mainly driven by the inter-sensory component. Recalibration transferred from vision to audition, but not from audition to vision. These results indicate that motor-sensory and inter-sensory components contribute to recalibration in a modality-dependent manner
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