Abundance, Biomass, and Diversity of Aquatic Invertebrates in Level Ditches and Adjacent Natural Emergent Marsh in an Eastern South Dakota Wetland

The aquatic invertebrate communities of level ditches and adjacent natural emergent marsh in a South Dakota prairie wetland were sampled during the summer of 1982. Collections were made in both the water column and the bottom substrates. Forty-five taxa were collected. Analysis of variance indicated that a significantly greater mean number of taxa and a larger mean number of all macroinvertebrates were present in level ditches than in the natural emergent marsh. No differences were detected for mean biomass of all macroinvertebrate taxa collectively. Several taxa had a greater mean number and biomass in the level ditches than in the natural emergent marsh. Discussion of the composition of duck diets during the breeding and brood rearing seasons revealed that the level ditches provided an abundance and diversity of the aquatic invertebrates consumed by ducks

Prospects of brain–machine interfaces for space system control

The dream of controlling and guiding computer-based systems using human brain signals has slowly but steadily become a reality. The available technology allows real-time implementation of systems that measure neuronal activity, convert their signals, and translate their output for the purpose of controlling mechanical and electronic systems. This paper describes the state of the art of non-invasive brain-machine interfaces (BMIs) and critically investigates both the current technological limits and the future potential that BMIs have for space applications. We present an assessment of the advantages that BMIs can provide and justify the preferred candidate concepts for space applications together with a vision of future directions for their implementation. © 2008 Elsevier Ltd. All rights reserved

Introduction

This introduction surveys the prospects for developing a systematic comparative approach to Austronesian syntax and outlines the benefits of such an approach for syntactic theory. We begin with a brief overview of Austronesian languages, focusing on some typologically unusual aspects of their grammar, and the theoretical explanations that have been proposed for these features. We then survey the articles in the rest of this volume and the theoretical questions they address. A novel feature of this special issue is that each article is followed by a commentary by another Austronesian linguist which engages the same issues from a different perspective. The pairings of article and commentary should give readers a window into the study of Austronesian syntax and its current contributions to linguistic theory

Peripheral Dynamic Stereovision – A Novel Stereoscopic Test

This work proposes and experimentally evaluates a new method and the first prototypic design of an apparatus for the objective assessment of peripheral dynamic stereovision. Peripheral dynamic stereovision is understood as the ability to perceive, recognize and observe moving objects in the visual periphery without sacrificing foveal fixation, i.e. shifting the line of sight (e.g. moving the eyes or the head) and loosing attention to the scene of interest. The presence of stereopsis on top further enhances the perceptive quality by adding the third dimension with judgment of depth and estimation of relative spatial positions as central clues for orientation, coordinative interaction and navigation in space. Based on findings that moving stereoscopic contours can induce distinctive optokinetic reactions, a panoramic stimulus pattern was rotated round subjects’ heads. Designed after the Frisby Stereotest, solely the binocular parallax resulting from the plate thickness carries stereoscopic information, excluding all other depth clues. A specially fitted goggle frame assured correct binocular alignment of the subjects adding objectivity. In first experiments, voluntary reactions (pushing a buzzer button) and involuntarily triggered ocular responses have been registered. The Performance Level (PL) and Confidence Ratio (CR) were introduced as benchmarks for voluntary reactions. Despite larger spreads, the PL averaged at 60 % while an elevated CR confirmed a low error rate of 16 % and thus high overall credibility. Poor performance of available recording hard- and software, in many cases, rendered the analysis of involuntary ocular reactions less exhaustive. It was however observable that objects that appear in the periphery of the visual field triggered the onset of nystagmoid search and tracking mechanisms. Finally, mean peripheral locations of subjects’ active reactions have been established at 30 degrees. The outcome of this pilot study in principle confirmed basic feasibility, conceptual validity and practical applicability of this novel method. Prospective fields of application with raised demands on peripheral dynamic stereopsis have been identified and critically assessed. The applicative possibilities and exclusive advantages of this test combining the assessment of stereopsis and dynamic visual field testing have not been matched by solutions published so far. Before however commercialization should be aimed at, design-related issues, including the implementation of electrophysiological ocular measurements, need to be addressed first to lead the post-prototype development to higher diagnostic expressiveness and reliability.In dieser Arbeit wird eine neuartige Methode zur objektiven Beurteilung des peripheren dynamischen Stereosehens vorgestellt und an einem dafür konstruierten Prototyp die generelle Machbarkeit gezeigt. Peripheres dynamisches Stereosehen ist die Fähigkeit des Wahrnehmens, Erkennens und Verfolgens sich bewegender Objekte im peripheren Gesichtsfeld unter Beibehaltung der Zentralfixierung des eigentlichen, anvisierten Zielobjektes. Das gleichzeitige Vorhandensein von Stereopsis erhöht die periphere Sehqualität durch Addition der dritten Dimension. Der Nutzen des peripheren dynamischen Stereosehens liegt in der Beurteilung von räumlicher Tiefe und Abschätzung relativer Positionen im Raum, was wichtige Hinweise zu Orientierung, Koordination, Zusammenwirken und Navigation im Raum liefert. Da Studien zeigten, dass bei funktionierender Stereopsis sich bewegende stereoskopische Muster, bzw. Konturen beurteilbare optokinetische Reaktionen hervorrufen, wurde ein panoramisches Stimulationsmuster nach dem bewährten Frisby Stereotest gestaltet und um die Köpfe der Probanden rotiert. Nur die Dicke der Plexiglasplatten enthält die stereoskopische Information in Form der binokularen Parallaxe. Sonstige möglicherweise verfälschende Tiefenhinweise sind per se ausgeschlossen. Probanden tragen dabei eine spezielle Blendenbrille über die eine korrekte binokulare Ausrichtung der Probanden gewährleistet wird und dadurch der Grad an Objektivität weiter gesteigert ist. In der Pilotstudie wurden willkürliche (Drücken eines Alarm-Tasters bei Objekterkennung) und unwillkürlich ausgelöste optokinetische Reaktionen der Probanden erfasst. Zur Beurteilung willkürlicher Reaktionen wurden der Performance Level (PL) und das Confidence Ratio (CR) als Bewertungsgrößen eingeführt. Trotz größerer Abweichungen zwischen den Probanden ergab sich ein durchschnittlicher PL von etwa 60% während ein hoher CR eine geringe Fehlerrate von ca. 16% ergab und somit hohe Glaubwürdigkeit bestätigte. Mit der verfügbaren Aufzeichnungsausrüstung war eine automatische und somit objektive Auswertung nur bedingt möglich. Grund waren Störpotentiale durch gelegentliches Blinzeln und kontinuierliche Fixations- und Stabilisationsbewegungen der Augen. Es war jedoch feststellbar, dass in das periphere Gesichtsfeld einlaufende stereoskopische Objekte Nystagmus-ähnliche Such- und Bewegungsmuster der Augen auslösten. Die Winkelpositionen bei peripherer Objekterkennung lagen bei durchschnittlich 30 Grad in der Peripherie. Das Resultat dieser Pilotstudie bestätigte generelle Machbarkeit, Konzeptgültigkeit und praktische Anwendbarkeit dieser neuen Testmethode. Mögliche Anwendungsfelder mit erhöhten Anforderungen an das periphere dynamische Stereosehen wurden identifiziert und kritisch bewertet. Die anwendungstechnischen Möglichkeiten und Vorteile dieser Methode, die die Beurteilung der Stereopsis und einer dynamischen Perimetrie kombiniert, wurden bis dato durch vergleichbare Umsetzungen noch nicht erreicht. Bevor jedoch eine kommerzielle Verwertbarkeit in Betracht gezogen werden kann, sollte das konsequent nächste Entwicklungsziel die Erhöhung der apparativen und methodischen Objektivität, d.h. der diagnostischen Aussagekraft, beispielsweise durch Automatisierung, sein. Das schließt konstruktionsbedingte Gegebenheiten und elektrophysiologische Messmethoden ein

Augmenting astronaut’s capabilities through brain-machine interfaces

Brain-Machine Interfaces (BMIs) transform the brain activity of a human operator into executable commands that can be sent to a machine, usually a computer or robot, to perform intended tasks. In addition to current biomedical applications, available technology could also make feasible augmenting devices for space applications that could be promising means to improve astronauts ’ efficiency and capabilities. The implementation of artificial intelligence algorithms into the software architecture of present BMIs will be of crucial importance to guarantee a proper functionality of the device in the highly dynamic and unpredictable space environment.

Social Perceptions of Intimate Partner Violence Among Same-sex Couples

N/ahttps://via.library.depaul.edu/psychologynight/1144/thumbnail.jp

Physical modeling of near-Earth Asteroid (29075) 1950 DA

Near-Earth Asteroid (29075) 1950 DA may closely encounter Earth in 2880. The probability of Earth impact may be as high as 1/300, but the outcome of the encounter depends critically on the physical properties of the asteroid [Giorgini et al., 2002. Science 196, 132-136]. We have used Arecibo and Goldstone radar data and optical lightcurves to estimate the shape, spin state, and surface structure of 1950 DA. The data allow two distinct models. One rotates prograde and is roughly spheroidal with mean diameter 1.16 ± 0.12  km. The other rotates retrograde and is oblate and about 30% larger. Both models suggest a nickel-iron or enstatite chondritic composition. Ground-based observations should be able to determine which model is correct within the next several decades.14 page(s

Radar observations of Itokawa in 2004 and improved shape estimation

We present June 2004 radar images of asteroid 25143 Itokawa (1998 SF36) that improve upon the longitude-latitude coverage of images obtained in 2001 by Ostro et al. (2004) and use the 2001-2004 data to refine that papers constraints on Itokawas shape. The 2004 images, the first of the asteroids southern side, look distinctly different from the 2001 images, revealing leading edges that are much more curved and rugged than the nearly convex leading edges seen at northern latitudes in 2001. Itokawa is shaped like a slightly asymmetrical, bent, lumpy ellipsoid with dimensions along the principal axes within 10% of 594 x 320 x 288 m. To illustrate the uncertainty space associated with shape reconstruction from images with suboptimal orientational coverage, we present two alternative three-dimensional models of the object.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202