1,351 research outputs found
Experimental analysis of sample-based maps for long-term SLAM
This paper presents a system for long-term SLAM (simultaneous localization and mapping) by mobile service robots and its experimental evaluation in a real dynamic environment. To deal with the stability-plasticity dilemma (the trade-off between adaptation to new patterns and preservation of old patterns), the environment is represented at multiple timescales simultaneously (5 in our experiments). A sample-based representation is
proposed, where older memories fade at different rates depending on the timescale, and robust statistics are used to interpret the samples. The dynamics of this representation are analysed in a five week experiment, measuring the relative influence of short- and long-term memories over time, and further demonstrating the robustness of the approach
Segment-specific expression of sodium-phosphate cotransporters NaPi-IIa and -IIc and interacting proteins in mouse renal proximal tubules
Sodium-dependent phosphate cotransport in renal proximal tubules (PTs) is heterogeneous with respect to proximal tubular segmentation (S1 vs. S3) and nephron generation (superficial vs. juxtamedullary). In the present study, S1 and S3 segments of superficial and juxtamedullary nephrons were laser-microdissected and mRNA and protein expression of the Na/Pi-cotransporters NaPi-IIa and NaPi-IIc and the PDZ proteins NHERF-1 and PDZK1 determined. Expression of NaPi-IIa mRNA decreased axially in juxtamedullary nephrons. There was no effect of dietary Pi content on NaPi-lla mRNA expression in any proximal tubular segment. The abundance of the NaPi-IIa cotransporter in the brush-border membrane showed inter- and intranephron heterogeneity and increased in response to a low-Pi diet (5days), suggesting that up-regulation of NaPi-lla occurs via post-transcriptional mechanisms. In contrast, NaPi-IIc mRNA and protein was up-regulated by the low-Pi diet in all nephron generations analysed. NHERF-1 and PDZK1, at both mRNA and protein levels, were distributed evenly along the PTs and did not change after a low-Pi die
The Political Influence of Older Americans
This essay explores the future prospects for the political influence of older Americans. Some analysts contend that the next fifty years will bring a marked increase in the political influence of the elderly. Others argue that the aged are unlikely to become a significant political influence at any time in the forseeable future. We review the relevant evidence and conclude that it is not entirely consistent with either of these positions. Our analysis suggests a third alternative, that there will be a marked increase in the political resources of the elderly, which will not necessarily translate into an increase in political influence
Relating imperatives to action
The aim of this chapter is to provide an analysis of the use of logically complex imperatives, in particular, imperatives of the form Do A1 or A2 and Do A, if B. We argue for an analysis of imperatives in terms of classical logic which takes into account the influence of background information on imperatives. We show that by doing so one can avoid some counter-intuitive results which have been associated with analyses of imperatives in terms of classical logic. In particular, I address Hamblin's observations concerning rule-like imperatives and Ross' Paradox. The analysis is carried out within an agent-based logical framework. This analysis explicates what it means for an agent to have a successful policy for action with respect to satisfying his or her commitments, where some of these commitments have been introduced as a result of imperative language use
Using audio stimuli in acceptability judgment experiments
In this paper, we argue that moving away from written stimuli in acceptability judgment experiments is necessary to address the systematic exclusion of particular empirical phenomena, languages/varieties, and speakers in psycholinguistics. We provide user‐friendly guidelines for conducting acceptability experiments which use audio stimuli in three platforms: Praat, Qualtrics, and PennController for Ibex. In supplementary materials, we include data and R script from a sample experiment investigating English constituent order using written and audio stimuli. This paper aims not only to increase the types of languages, speakers, and phenomena which are included in experimental syntax, but also to help researchers who are interested in conducting experiments to overcome the initial learning curve. Video Abstract link: https://www.youtube.com/watch?v=GoWYY1O9ugsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156434/2/lnc312377_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156434/1/lnc312377.pd
On Being Negative
This paper investigates the pragmatic expressions of negative evaluation (negativity) in two corpora: (i) comments posted online in response to newspaper opinion articles; and (ii) online reviews of movies, books and consumer products. We propose a taxonomy of linguistic resources that are deployed in the expression of negativity, with two broad groups at the top level of the taxonomy: resources from the lexicogrammar or from discourse semantics. We propose that rhetorical figures can be considered part of the discourse semantic resources used in the expression of negativity. Using our taxonomy as starting point, we carry out a corpus analysis, and focus on three phenomena: adverb + adjective combinations; rhetorical questions; and rhetorical figures. Although the analysis in this paper is corpus-assisted rather than corpus-driven, the final goal of our research is to make it quantitative, in extracting patterns and resources that can be detected automatically
Holistic corpus-based dialectology
This paper is concerned with sketching future directions for corpus-based dialectology. We advocate a holistic approach to the study of geographically conditioned linguistic variability, and we present a suitable methodology, 'corpusbased dialectometry', in exactly this spirit. Specifically, we argue that in order to live up to the potential of the corpus-based method, practitioners need to (i) abandon their exclusive focus on individual linguistic features in favor of the study of feature aggregates, (ii) draw on computationally advanced multivariate analysis techniques (such as multidimensional scaling, cluster analysis, and principal component analysis), and (iii) aid interpretation of empirical results by marshalling state-of-the-art data visualization techniques. To exemplify this line of analysis, we present a case study which explores joint frequency variability of 57 morphosyntax features in 34 dialects all over Great Britain
Reflexionar sobre Prácticas de Enseñanza y Residencias en Pandemia
Entendemos a las situaciones educativas situadas en contexto y caracterizadas por su incertidumbre, singularidad, complejidad e historicidad (Sanjurjo, 2020). Por lo tanto, en las condiciones particulares que se plantearon a partir del aislamiento social obligatorio nos preguntamos qué trayectos de residencias se podrían desplegar y cómo. Una primera cuestión que analizamos fue si las situaciones educativas desarrolladas de modo remoto serían una experiencia formativa para las y los practicantes en tanto fueran instancias que promovieran los aprendizajes requeridos para nuestra asignatura. Aquí los aportes de Dussel (2020) resultaron claves para identificar que a pesar de que el encuentro entre residente y estudiantes fuera diferido y no simultáneo, se generaban conversaciones pedagógicas que como tales tienen la potencialidad de fomentar aprendizajes. A su vez, las decisiones didácticas que se toman en estos contextos podrían ser objeto de reflexión en función de las características de la conversación que pudiera establecerse. Por otra parte, reflexionamos acerca de cuáles serían aquellos aprendizajes esenciales que no se estarían pudiendo desarrollar en este contexto y evaluamos si estos aprendizajes serían imprescindibles para la acreditación de la residencia. En este sentido, identificamos claramente que un aprendizaje que quedaría pendiente es la gestión de las situaciones que se despliegan cuando las personas y sus cuerpos comparten un mismo espacio y tiempo. Sin embargo, las condiciones de aislamiento planteaban nuevos desafíos y exigían saberes para los cuales las y los docentes en el ejercicio de su profesión no tuvieron formación específica (Sanjurjo, 2020). En suma, aceptamos que algunas situaciones no serían experimentadas en esta residencia, pero no por ello el trayecto ofrecido dejaría de brindar oportunidades para reflexionar y desarrollarse como futuros profesionales de la educación en Biología.publishedVersionFil: Occelli, Maricel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Enseñanza de la Ciencia y la Tecnología. Cátedra de Práctica de la Enseñanza; Argentina.Fil: Biber, Priscila Ariadna. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Enseñanza de la Ciencia y la Tecnología. Cátedra de Práctica de la Enseñanza; Argentina.Fil: Fussero, Gimena B. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Enseñanza de la Ciencia y la Tecnología. Cátedra de Práctica de la Enseñanza; Argentina.Fil: Mari, Macarena Mariel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Enseñanza de la Ciencia y la Tecnología. Cátedra de Práctica de la Enseñanza; Argentina
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