Showing papers by "University of Texas at Arlington published in 1970"

Analysis of Dynamic Response of Highway Bridges

Abstract: A method for the computation of the dynamic response of highway bridges under the action of moving vehicles is presented. The bridge is idealized as a single, linearly elastic beam with distributed flexibility and concentrated point masses, and the vehicle is represented as a three-axle sprung load, with due account taken of the effect of interleaf friction in its suspension system. The application of this method to numerous research investigations is reviewed, and the dynamic resopnse characteristics of certain cantilever bridges are analyzed, with particular reference to the relative susceptibility to vibration of this and other bridge types.

Preparatory state effects in intersensory facilitation

Abstract: Four trained Ss participated in a task concerned with intersensory facilitation of reaction time (RT). Discriminative RT to a visual event was longer than discriminative RT to a combined auditory-visual event, even though the auditory event by itself was a catch signal. The magnitude of this difference was greater with a long (5.5 sec) as opposed to short (.5 sec) foreperiod delay. This finding supported the hypothesis that the auditory component of the combined event serves a preparatory state role by enhancing response readiness, a role that is manifest to the extent that S’s prior degree of preparation is nonoptimal.

The righting reflex in turtles: A description and comparison*

Abstract: Sixty-three turtles, representing 50 species, were tested for the righting reflex under two conditions, inversion and suspension. Ninety-two percent performed the righting reflex under inversion; 67% performed the righting reflex under suspension. Differences in the performance of the righting reflex were noted and discussed in terms of natural selection and the evolutionary relationships between the species sampled.

Reward magnitude and instrumental responses: Consistent and partial reward

Abstract: Two studies using partial or consistent large (500 mg) and small (45 mg) reward are presented. In both studies, after extended reward acquisition, differences are negligible or nonexistent. Results from the partial reward groups indicate extinction differences also disappear after extended training. These results do not seem to be in line with usual assumptions regarding the effects of reward magnitude.

Discrete Fourier and Hadamard transforms

Abstract: Elementary properties of discrete Fourier transforms (d.f.t.) have appeared in recent literature. Corresponding properties of BIFORE (Hadamard) transforms are summarised and compared with those of the d.f.t.

Complex BIFORE transform

Abstract: A complex BIFORE transform is defined and elementary properties of the transform are developed.

Sensitivity and decisional factors in the psychological refractory period

Abstract: Three trained Ss responded to a pair of events presented at fixed interstimulus intervals (ISIs) of 33, 67, and 100 msec. Each event was the independent presence of a visual stimulus (S-P) or its absence (S-A), to which Ss were to respond or not, with a set for speed over accuracy. The probabilities of Sop occurrence [P(S)] to each of the events were varied. Pretrial verbal reports or behavioral hypotheses (BHs) werealso obtained. P(S), ISI, BH, and order (first vs second event) were all generally determinants of both RT to Sop and inhibition probability to S-A. However, when the RT data were corrected for inhibition probability, order was the only systematic effect that remained. The results were discussed in terms of approaches to the psychological refractory period derived from signal detection theory involving differential sensitivity as opposed to criterion.

Developments in Trading Patterns in the Common Market and EFTA

Abstract: The European Economic Community (EEC) was created in January, 1958. The European Free Trade Association (EFTA) was organized two years later with the intent to “catch up” within six months. These markets provide instances of two major types of discrimination, namely a customs union and a free-trade area. They have now functioned long enough to permit useful examination of the trading patterns that have developed in the wake of discrimination. The purpose of this article is to examine the trading relations of these two markets between 1960 and 1967 using a particular measure of trading intensity. The concern is changes in trading patterns and their causes rather than the welfare implications of such changes.

Spectral analysis of linear digital systems using BIFORE

Abstract: A spectral analysis of linear digital systems using BIFORE is carried out. Expressions for power and amplitude spectra of the input and output signals are developed. The frequency-sequency structure of the power spectra, which are invariant to cyclic shift of the sampled data, is analysed.

Material Engagements: Science Studies and the Environmental Humanities

Abstract: Key words: materiality, natural world, humanities , ethical ecocriticism , agency In the twentieth century the principle tendency has been to denigrate the value of non-human nature. In this sense, scientific studies can help recover the materiality of the natural world for research in the humanities, especially when dealing with ecocriticism. Our current image of the environment has been deprived of its living beings and turned into an empty space at the disposal of humans. Natural sciences can provide theoretical and methodological models which can advance ethical and political projects of ecocriticism and encourage research that would consider the materiality of the non-human world, thereby restoring entity to the natural world. Twenty-first century environmental movements need to view the material and natural world as subjects with agency and not take for granted that these exist “somewhere out there.” Palabras clave: materia, naturaleza no humana, humanidades, etica ecocritica, agencia En el siglo XX la tendencia fundamental hacia el medioambiente fue la de menospreciar el valor de la naturaleza no humana. En este sentido, los estudios cientificos pueden ayudar a recuperar la materialidad del mundo natural para la investigacion de las humanidades, especialmente en lo que concierne a la ecocritica. El medioambiente actual ha sido privado de sus seres vivos y convertido en un espacio vacio a disposicion del ser humano. Las ciencias naturales pueden aportar modelos teoricos y metodologicos que hagan avanzar los proyectos eticos y politicos de la ecocritica, en definitiva, crear una investigacion que considere la materialidad del mundo no humano: que devuelva entidad al mundo natural. Los movimientos medioambientalistas del siglo XXI deben contemplar el mundo material y natural como sujeto agente, pues no se puede dar por sentado que estos existen “por ahi, en alguna parte.”

Mean g Values of Rare-Earth Ions: Extension to Monoclinic Symmetries

Abstract: A previous calculation of the mathematical properties of a Kramers doublet for extrema of the mean $g$ value is extended to monoclinic symmetries. The theory is applied to the paramagnetic resonance data for La${\mathrm{F}}_{3}$: ${\mathrm{Yb}}^{3+}$. These data are shown to be consistent with a ${\mathrm{Yb}}^{3+}$ site of ${\mathrm{C}}_{2v}$ point symmetry.

Use of tone offset to facilitate reaction time to light onset

Abstract: Four Ss participated in a visual discriminative reaction time (RT) task to explore the phenomenon of intersensory facilitation. Previous research has indicated that RT to a joint visual-auditory event is more rapid than RT to the visual component alone, even when the auditory component is noninformative. In the present study, a tone offset was used in place of the usual affirmative event (click). The results indicated that RT was more rapid when the tone offset in conjunction with the occurrence of the visual event as compared to when the tone remained on throughout the trial. The effect was comparable in magnitude to that obtained in prior studies using an affirmative auditory event.

The PREE after minimal acquisition: Goal box placement with single pellet reward

Abstract: Two groups of rats were given goalbox placements directly over the food cup. Group P was rewarded with a single 1,000-mg pellet on Placements 1, 3, and 5, while Group C was rewarded on each placement. The usual PREE was obtained when Ss ran the full length of the alley. The study supports earlier results and extends them to a single pellet reward situation.

When estimating reachability in space, young children and the elderly are similar

Abstract: This study examined the age-related ability to mentally represent action in the context of reach estimation via use of motor imagery in children, young adults, and a group of older adults. Participants were instructed to estimate whether randomly presented targets in peripersonal (within actual reach) and extrapersonal (beyond reach) space were within or out of reach of their dominant limb while seated. In regard to total accuracy, results indicated that children and older adults were similar, but scores were significantly lower than those of young adults. Whereas all groups displayed greater error in extrapersonal space, once again children and older adults were similar, but significantly different than young adults. That is, children and older adults displayed greater overestimation responses. Although other factors are discussed, the literature provides a hint that differences are due in part to distinctions in brain structure and functioning. .