196 research outputs found
Highly satisfactory alkynylation of alkenyl halides via Pd-catalyzed cross-coupling with alkynylzincs and its critical comparison with the Sonogashira alkynylation
No full textThe Pd-catalyzed alkynylation of various alkenyl halides and triflates with alkynylzincs proceeds well even with alkynyl derivatives containing electron-withdrawing groups. The reaction appears to be highly general. Noteworthy is that the corresponding Sonogashira reactions under various reported conditions are significantly less satisfactory in all cases performed in this study
Vocal learning with inverse models
No full textUnderstanding how populations of neurons encode information is the challenge faced by researchers in the field of neural coding. Focusing on the many mysteries and marvels of the mind has prompted a prominent team of experts in the field to put their heads together and fire up a book on the subject. Simply titled Principles of Neural Coding, this book covers the complexities of this discipline. It centers on some of the major developments in this area and presents a complete assessment of how neurons in the brain encode information. The book collaborators contribute various chapters that describe results in different systems (visual, auditory, somatosensory perception, etc.) and different species (monkeys, rats, humans, etc). Concentrating on the recording and analysis of the firing of single and multiple neurons, and the analysis and recording of other integrative measures of network activity and network states—such as local field potentials or current source densities—is the basis of the introductory chapters.- Provides a comprehensive and interdisciplinary approach- Describes topics of interest to a wide range of researchersThe book then moves forward with the description of the principles of neural coding for different functions and in different species and concludes with theoretical and modeling works describing how information processing functions are implemented. The text not only contains the most important experimental findings, but gives an overview of the main methodological aspects for studying neural coding. In addition, the book describes alternative approaches based on simulations with neural networks and in silico modeling in this highly interdisciplinary topic. It can serve as an important reference to students and professionals
Exploring Choreographers’ Conceptions of Motion Capture for Full Body Interaction
No full textWe present the results of a group interview of choreographers aimed at understanding their conceptions of how movement can be used to in live performance. This understanding intended to inform research into full body interaction for live performance and other more general full body interfaces. The results of the interview suggest a new way of conceiving of interaction with digital technology, neither as a representation of movement, not as an interface that responds to movement but as a means of transforming movement. This transformed movement can then serve as a starting point for a dancers responses to transformations of their own movement thus setting up an improvisational feedback loop
Metabotropic Glutamate Receptor 5 as a Point of Convergence for Models of Obsessive-Compulsive Disorder and Autism Spectrum Disorder
No full textRefers To Kristen K. Ade, Yehong Wan, Harold C. Hamann, Justin K. O’Hare, Weirui Guo, Anna Quian, Sunil Kumar, Srishti Bhagat, Ramona M. Rodriguiz, William C. Wetsel, P. Jeffrey Conn, Kafui Dzirasa, Kimberly M. Huber, Nicole Calakos Increased Metabotropic Glutamate Receptor 5 Signaling Underlies Obsessive-Compulsive Disorder-like Behavioral and Striatal Circuit Abnormalities in Mice Biological Psychiatry, Volume 80, Issue 7, 1 October 2016, Pages 522-533 PDF (4033 K) Supplementary conten
Extracting information in spike time patterns with wavelets and information theory
No full textWe present a new method to assess the information carried by temporal patterns in spike trains. The method first performs a wavelet decomposition of the spike trains, then uses Shannon information to select a subset of coefficients carrying information and, finally, assesses timing information in terms of decoding performance - the ability to identify the presented stimuli from spike train patterns. We show that the method allows: i) a robust assessment of the information carried by spike time patterns even when this is distributed across multiple time-scales and time-points, ii) an effective denoising of the raster plots that improves the estimate of stimulus tuning of spike trains, and iii) an assessment of the information carried by temporally coordinated spikes across neurons. Using simulated data we demonstrate that the Wavelet-Information (WI) method performs better and is more robust to spike time-jitter, background noise and sample size than well-established approaches, such as principal component analysis, direct estimates of information from digitized spike trains or a metric-based method. Furthermore, when applied to real spike trains from monkey auditory cortex and from rat barrel cortex, the WI method allows extracting larger amounts of spike timing information. Importantly, the fact that the WI method incorporates multiple time-scales makes it robust to the choice of partly arbitrary parameters such as temporal resolution, response window length, number of response features considered, or the number of available trials. These results highlight the potential of the proposed method for accurate and objective assessments of how spike timing encodes information
Franco, Marta G. (2024). Las redes son nuestras
No full textMarta G. Franco examines how big tech corporations have usurped digital spaces, transforming the internet and social networks into tools of control, exploitation, and surveillance. The author denounces the capitalist and patriarchal appropriation of these environments, dominated by a male and Western elite that perpetuates exclusion and inequality. Through a feminist, hacktivist, and decolonial perspective, she highlights the importance of creating self-managed, inclusive, and collaborative digital spaces, inspired by initiatives such as hacklabs and hackmeetings. The book advocates for a more ethical and diverse internet, where social movements and marginalized communities reclaim control.Marta G. Franco examina cómo las grandes corporaciones tecnológicas han usurpado los espacios digitales, transformando internet y las redes sociales en herramientas de control, explotación y vigilancia. La autora denuncia la apropiación capitalista y patriarcal de estos entornos, dominados por una élite masculina y occidental que perpetúa la exclusión y las desigualdades. A través de una perspectiva feminista, hacktivista y decolonial, destaca la importancia de crear espacios digitales autogestionados, inclusivos y colaborativos, inspirados en iniciativas como hacklabs y hackmeetings. El libro propone una internet más ética y diversa, donde los movimientos sociales y las comunidades marginadas recuperen el control
Comment on Performance of Different Synchronization Measures in Real Data: A Case Study on Electroencephalographic Signals
No full textQuian Quiroga [Phys. Rev. E 65, 041903 (2002)] reported a similar performance of several linear and nonlinear measures of synchronization when applied to the rat electrocorticogram (ECoG). However, they found that the mutual information measure did not produce robust estimates of synchronization when compared to other measures. We reexamined their data using a histogram method with adaptive partitioning and found the mutual information to be a useful measure of regional ECoG interdependence
Engineered cementitious composites with low volume of cementitious materials
No full textEngineered cementitious composite (ECC) is an ultra ductile cement-based material reinforced with fibers. It is characterized by high tensile ductility and tight crack width control. Thanks to the excellent performance, ECC is emerging in broad applications to enhance the loading capacity and the durability of structures. However, ECC also faces a limitation on dimensional stability and on economical and sustainable issues. In general, a large amount of cementitious materials, often more than 70% by weight, is used in ECC and no coarse aggregate is allowed to be added. The high volume of cementitious materials in ECC results in a large drying shrinkage and negative effects on material cost and material greenness. In this paper, a new version of ECC is designed with low volume of cementitious materials about 25% by weight, including Portland cement, blast furnace slag and silica fume, and a large amount of filler and aggregate, including limestone powder and river sand. In this mix, only 1.2% of fibers by volume is mixed, which is 60% dosage of standard ECC. Experimental study reveals that the newly developed ECC shows tensile ductility of 2% and relatively low shrinkage. Considering the low cementitious material and fiber contents, the newly developed ECC might have a reduced cost and increased material greenness.Structural EngineeringCivil Engineering and Geoscience
Neural correlates of learning and trajectory planning in the posterior parietal cortex
No full textabstract: The posterior parietal cortex (PPC) is thought to play an important role in the planning of visually-guided reaching movements. However, the relative roles of the various subdivisions of the PPC in this function are still poorly understood. For example, studies of dorsal area 5 point to a representation of reaches in both extrinsic (endpoint) and intrinsic (joint or muscle) coordinates, as evidenced by partial changes in preferred directions and positional discharge with changes in arm posture. In contrast, recent findings suggest that the adjacent medial intraparietal area (MIP) is involved in more abstract representations, e.g., encoding reach target in visual coordinates. Such a representation is suitable for planning reach trajectories involving shortest distance paths to targets straight ahead. However, it is currently unclear how MIP contributes to the planning of other types of trajectories, including those with various degrees of curvature. Such curved trajectories recruit different joint excursions and might help us address whether their representation in the PPC is purely in extrinsic coordinates or in intrinsic ones as well. Here we investigated the role of the PPC in these processes during an obstacle avoidance task for which the animals had not been explicitly trained. We found that PPC planning activity was predictive of both the spatial and temporal aspects of upcoming trajectories. The same PPC neurons predicted the upcoming trajectory in both endpoint and joint coordinates. The predictive power of these neurons remained stable and accurate despite concomitant motor learning across task conditions. These findings suggest the role of the PPC can be extended from specifying abstract movement goals to expressing these plans as corresponding trajectories in both endpoint and joint coordinates. Thus, the PPC appears to contribute to reach planning and approach-avoidance arm motions at multiple levels of representation.View the article as published at http://journal.frontiersin.org/article/10.3389/fnint.2013.00039/ful
Fixation-related potentials in visual search: A combined EEG and eye tracking study
No full textWe report a study of concurrent eye movements and electroencephalographic (EEG) recordings while subjects freely explored a search array looking for hidden targets. We describe a sequence of fixation-event related potentials (fERPs) that unfolds during ̃ 400 ms following each fixation. This sequence highly resembles the event-related responses in a replay experiment, in which subjects kept fixation while a sequence of images occurred around the fovea simulating the spatial and temporal patterns during the free viewing experiment. Similar responses were also observed in a second control experiment where the appearance of stimuli was controlled by the experimenters and presented at the center of the screen. We also observed a relatively early component (̃150 ms) that distinguished between targets and distractors only in the freeviewing condition. We present a novel approach to match the critical properties of two conditions (targets/distractors), which can be readily adapted to other paradigms to investigate EEG components during free eye-movements. © 2012 ARVO.Fil: Kamienkowski, Juan Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Neurociencia Integrativa; ArgentinaFil: Ison, Matias Julian. University of Leicester; Reino UnidoFil: Quiroga, Rodrigo Quian. University of Leicester; Reino UnidoFil: Sigman, Mariano. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Neurociencia Integrativa; Argentin
- …
