Phenomenal regression to the real object in physical and virtual worlds

© 2014, Springer-Verlag London. In this paper, we investigate a new approach to comparing physical and virtual size and depth percepts that captures the involuntary responses of participants to different stimuli in their field of view, rather than relying on their skill at judging size, reaching or directed walking. We show, via an effect first observed in the 1930s, that participants asked to equate the perspective projections of disc objects at different distances make a systematic error that is both individual in its extent and comparable in the particular physical and virtual setting we have tested. Prior work has shown that this systematic error is difficult to correct, even when participants are knowledgeable of its likelihood of occurring. In fact, in the real world, the error only reduces as the available cues to depth are artificially reduced. This makes the effect we describe a potentially powerful, intrinsic measure of VE quality that ultimately may contribute to our understanding of VE depth compression phenomena

A STUDY TO DETERMINE THE EFFECT OF SPEED-BUILDING EXERCISES OF ONE, TWO, AND THREE MINUTES UPON ACHIEVEMENT IN FIRST-YEAR TYPEWRITING

The purpose of this study is to determine whether students who practice daily for one, two and three minutes on speed building drills at the beginning of each typewriting period will improve their typewriting achievement in speed on straight-copy tests of ten minutes duration over those students who do not practice on the same type of work

Indicadores de la calidad académica de las universidades acreditadas de El Salvador (2009-2013) y su impacto en el desarrollo económico

Este artículo explora datos cuantitativos de las nueve universidades acreditadas de El Salvador y hace una evaluación (20092013) de los principales indicadores educativos. Los resultados evidencian un posicionamiento de cuatro universidades acreditadas, reflejando diferencias significativas en los principales indicadores de calidad académica. Por otro lado, se mantienen bajas tasas de graduados en las áreas de Ciencias, con un escaso 1% en los últimos años, lo que evidencia que la ciencia no ha tenido prioridad en las políticas de Estado; además, como país mantenemos bajas tasas de inversión, en relación al PIB, en Actividades de Ciencia y Tecnología (ACT)—0.98%, en Inversión y Desarrollo (I&D)— 0.03%, y en el número de investigadores (533). Estos resultados afectan el desempeño económico del país, producto de la baja productividad de las empresas salvadoreñas, escasa inversión en ACT, en I&D, teniendo a la base la escasa o nula vinculación que tienen las universidades con la Industria, panorama que ha sido constante, requiriendo acciones de parte de los actores de la sociedad para hacer políticas públicas que impacten en el sistema educativo

Phenomenal regression as a potential metric of veridical perception in virtual environments

It is known that limitations of the visual presentation and sense of presence in a virtual environment (VE) can result in deficits of spatial perception such as the documented depth compression phenomena. Investigating size and distance percepts in a VE is an active area of research, where different groups have measured the deficit by employing skill-based tasks such as walking, throwing or simply judging sizes and distances. A psychological trait called phenomenal regression (PR), first identified in the 1930s by Thouless, offers a measure that does not rely on either judgement or skill. PR describes a systematic error made by subjects when asked to match the perspective projections of two stimuli displayed at different distances. Thouless’ work found that this error is not mediated by a subject’s prior knowledge of its existence, nor can it be consciously manipulated, since it measures an individual’s innate reaction to visual stimuli. Furthermore he demonstrated that, in the real world, PR is affected by the depth cues available for viewing a scene. When applied in a VE, PR therefore potentially offers a direct measure of perceptual veracity that is independent of participants’ skill in judging size or distance. Experimental work has been conducted and a statistically significant correlation of individuals’ measured PR values (their ‘Thouless ratio’, or TR) between virtual and physical stimuli was found. A further experiment manipulated focal depth to mitigate the mismatch that occurs between accommodation and vergence cues in a VE. The resulting statistically significant effect on TR demonstrates that it is sensitive to changes in viewing conditions in a VE. Both experiments demonstrate key properties of PR that contribute to establishing it as a robust indicator of VE quality. The first property is that TR exhibits temporal stability during the period of testing and the second is that it differs between individuals. This is advantageous as it yields empirical values that can be investigated using regression analysis. This work contributes to VE domains in which it is desirable to replicate an accurate perception of space, such as training and telepresence, where PR would be a useful tool for comparing subjective experience between a VE and the real world, or between different VEs

Role of MCP‐1 and MIP‐1α in retinal neovascularization during postischemic inflammation in a mouse model of retinal neovascularization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141957/1/jlb0137.pd

Inference in Ecology: The Sea Urchin Phenomenon in the Northwestern Atlantic

We have reviewed the considerable body of research into the sea urchin phenomenon responsible for the alternation between macroalgal beds and coralline barrens in the northwestern Atlantic. In doing so, we have identified problems with both the scientific approach and the interpretation of results. Over a period of approximately 20 years, explanations for the phenomenon invoked four separate scenarios, which changed mainly as a consequence of extraneous events rather than experimental testing. Our specific concerns are that results contrary to the keystone-predator paradigm for the American lobster were circumvented, system components of the various scenarios became accepted without testing, and modifications of some components appeared arbitrary. Our review illustrates dilemmas that, we suggest, have hindered ecological progress in general. We argue for a more rigorous experimental approach, based on sound natural-history observations and strong inference. Moreover, we believe that the scientific community needs to be cautious about allowing paradigms to become established without adequate scrutiny

Toll-Like Receptor 4 (TLR4) of Retinal Pigment Epithelial Cells Participates in Transmembrane Signaling in Response to Photoreceptor Outer Segments

Retinal pigment epithelial (RPE) cells mediate the recognition and clearance of effete photoreceptor outer segments (POS), a process central to the maintenance of normal vision. Given the emerging importance of Toll-like receptors (TLRs) in transmembrane signaling in response to invading pathogens as well as endogenous substances, we hypothesized that TLRs are associated with RPE cell management of POS. TLR4 clusters on human RPE cells in response to human, but not bovine, POS. However, TLR4 clustering could be inhibited by saturating concentrations of an inhibitory anti-TLR4 mAb. Furthermore, human POS binding to human RPE cells elicited transmembrane metabolic and calcium signals within RPE cells, which could be blocked by saturating doses of an inhibitory anti-TLR4 mAb. However, the heterologous combination of bovine POS and human RPE did not trigger these signals. The pattern recognition receptor CD36 collected at the POS–RPE cell interface for both homologous and heterologous samples, but human TLR4 only collected at the human POS–human RPE cell interface. Kinetic experiments of human POS binding to human RPE cells revealed that CD36 arrives at the POS–RPE interface followed by TLR4 accumulation within 2 min. Metabolic and calcium signals immediately follow. Similarly, the production of reactive oxygen metabolites (ROMs) was observed for the homologous human system, but not the heterologous bovine POS–human RPE cell system. As (a) the bovine POS/human RPE combination did not elicit TLR4 accumulation, RPE signaling, or ROM release, (b) TLR4 arrives at the POS–RPE cell interface just before signaling, (c) TLR4 blockade with an inhibitory anti-TLR4 mAb inhibited TLR4 clustering, signaling, and ROM release in the human POS–human RPE system, and (d) TLR4 demonstrates similar clustering and signaling responses to POS in confluent RPE monolayers, we suggest that TLR4 of RPE cells participates in transmembrane signaling events that contribute to the management of human POS

Shorebirds as integrators and indicators of mudflat ecology

Shorebirds are major, but thus far under-acknowledged, players in mudflat food webs and associated physio-chemical processes. Mud is a critical habitat type for shorebirds, offering a multi-dimensional matrix of feeding opportunities through space and time. Shorebirds have evolved a spectrum of foraging modes with associated morphologies, and sensory and physiological adaptations which exploit these foraging opportunities. Although shorebirds are mud specialists and sentinels of mudflat ecosystem functioning, they have not yet been well integrated into the “mud club”. In this chapter, we highlight the key roles shorebirds play in food webs, and in physical and chemical processes within mudflat ecosystems. We illustrate how shorebird distribution and behaviour provides a mirror of mudflat ecology because their foraging behaviour reflects the underlying ecological conditions, including temporal and spatial patterns in food/community structure in and across mud. In particular, shorebirds may be important indicators of essential fatty acid production by diatoms in epibenthic biofilm fields covering muddy intertidal flats, especially in estuaries. We conclude by highlighting the major challenges facing shorebirds today and call for a paradigm shift in shorebird conservation, based on recreating and restoring intertidal mud ecosystems

Análisis sobre la calidad académica de las universidades en El Salvador

El fenómeno de globalización exige una modernización del aparato productivo de los paises, el cual no puede lograrse sin la base científica y tecnológica, que generalmente es proporcionada por las universidades. Las empresas requieren procesos de gestión orientados a mejorar la calidad y el valor de los productos; y son las universidades quienes tienen el rol de la formación de recursos humanos de más alto nivel y constituyen un factor clave para incrementar la competitividad y mejorar la calidad de bienes y servicios. ¿Cuál es el nivel de calidad de nuestras universidades? ¿Qué significa la certificación ISO frente al proceso de acreditación? ¿Cómo se mide la calidad de las universidades? ¿Qué pasará con las Universidades no acreditadas? ¿Cuáles son los indicadores clave que aproximan a la calidad educativa:, este artículo da respuesta a estas interrogantes