6,331 research outputs found
Searching for plasticity in dissociated cortical cultures on multi-electrode arrays
We attempted to induce functional plasticity in dense cultures of cortical cells using stimulation through extracellular electrodes embedded in the culture dish substrate (multi-electrode arrays, or MEAs). We looked for plasticity expressed in changes in spontaneous burst patterns, and in array-wide response patterns to electrical stimuli, following several induction protocols related to those used in the literature, as well as some novel ones. Experiments were performed with spontaneous culture-wide bursting suppressed by either distributed electrical stimulation or by elevated extracellular magnesium concentrations as well as with spontaneous bursting untreated. Changes concomitant with induction were no larger in magnitude than changes that occurred spontaneously, except in one novel protocol in which spontaneous bursts were quieted using distributed electrical stimulation
Using Standardized Student Evaluation Instruments To Measure Teaching Effectiveness In Lecture/Recitation Mode Classes
This paper investigates the variability of student teaching effectiveness survey evaluations among the various recitation sections when lecture/recitation instruction is utilized with the same instructor both delivering the lecture and teaching all of the corresponding recitation sections. The research results indicate that when an instructor teaches multiple sections using lecture/recitation instruction, then the meaningful measure of the instructor’s teaching is the average of the student ratings for the various recitation sections. This study focuses on the variability of the students’ responses to each item in the survey instrument as measured by its standard deviation
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The cost of proactive interference is constant across presentation conditions
Proactive interference (PI) severely constrains how many items people can remember. For example, Endress and Potter (2014a) presented participants with sequences of everyday objects at 250 ms/picture, followed by a yes/no recognition test. They manipulated PI by either using new images on every trial in the unique condition (thus minimizing PI among items), or by re-using images from a limited pool for all trials in the repeated condition (thus maximizing PI among items). In the low-PI unique condition, the probability of remembering an item was essentially independent of the number of memory items, showing no clear memory limitations; more traditional working memory-like memory limitations appeared only in the high-PI repeated condition. Here, we ask whether the effects of PI are modulated by the availability of long-term memory (LTM) and verbal resources. Participants viewed sequences of 21 images, followed by a yes/no recognition test. Items were presented either quickly (250 ms/image) or sufficiently slowly (1500 ms/image) to produce LTM representations, either with or without verbal suppression. Across conditions, participants performed better in the unique than in the repeated condition, and better for slow than for fast presentations. In contrast, verbal suppression impaired performance only with slow presentations. The relative cost of PI was remarkably constant across conditions: relative to the unique condition, performance in the repeated condition was about 15% lower in all conditions. The cost of PI thus seems to be a function of the relative strength or recency of target items and interfering items, but relatively insensitive to other experimental manipulations
Sensory profile of portuguese white wines using long-term memory: a novel nationwide approach
White wine sensory profiling of all 12 Protected Geographical Indications (PGIs)
of mainland Portugal was achieved through completion of extended sensory
questionnaires by 20 professional wine experts. No samples were assessed; the
experiment was based on memory alone. Three macro-zonings were found and
typicality differences were statistically validated and sensory described. PGI
MINHO was found the most typical of all PGIs, with several extreme rates on
Color, Aroma and Taste. SOUTHERN cluster of the four meridional PGIs
presented several extreme, therefore typical, sensory assessments, mostly opposite
to the profile of PGI Minho. Color tonality, alcohol and acidity were mutually
related and respective variations were correlated with published findings and
expressed as key factors for regional macro-zoning differentiation. Moreover, with
the proposed methodology it was possible to achieve a novel nationwide sensory
characterization of PGIs, overcoming ongoing macroscaling and sample
representativeness limitations and envisaging new nation-sized sensory studiesinfo:eu-repo/semantics/publishedVersio
Atividade extensionista em serviços de saúde em um municÃpio do Rio Grande do Sul
Identificou-se que o desconhecimento dos serviços ofertados em um municÃpio dificultava o encaminhamento dos usuários para os serviços de apoio, especialmente no momento da alta hospitalar. Este estudo tem como objetivo relatar a experiência de uma intervenção junto aos trabalhadores da saúde de um municÃpio do Rio Grande do Sul. Foi realizado com trabalhadores da Rede de Atenção à Saúde por uma equipe multiprofissional nos anos de 2014 e 2015. Foram produzidas cartilhas informativas e banner com os principais serviços de saúde do municÃpio. Em conclusão, deve-se considerar a continuidade da atividade extensionista com vistas a ampliar o número de serviços de saúde atendidos e contribuir para a comunicação e integração ensino-serviço
Long-Term Activity-Dependent Plasticity of Action Potential Propagation Delay and Amplitude in Cortical Networks
Background: The precise temporal control of neuronal action potentials is essential for regulating many brain functions. From the viewpoint of a neuron, the specific timings of afferent input from the action potentials of its synaptic partners determines whether or not and when that neuron will fire its own action potential. Tuning such input would provide a powerful mechanism to adjust neuron function and in turn, that of the brain. However, axonal plasticity of action potential timing is counter to conventional notions of stable propagation and to the dominant theories of activity-dependent plasticity focusing on synaptic efficacies. Methodology/Principal Findings: Here we show the occurrence of activity-dependent plasticity of action potentia
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