The asymptotic distribution for the two-absorbing-barrier beta model

For the two-absorbing-barrier specialization of Luce's beta learning model, the asymptotic distribution of the response probability has all its density atp = 0 andp = 1. The functional equation for the amount of the density atp = 1 is investigated in this paper.Abstracted from a portion of the author's doctoral dissertation, University of Pennsylvania, June 1960. The author is indebted to Prof. B. Epstein and to Prof. Robert R. Bush, his dissertation supervisor, for the valuable help and encouragement received from them.The author is grateful to the Moore School for the support extended to him during his doctoral studies. He also wishes to thank D. Parkhill and N. Finkelstein of General Dynamics for their encouragement of his work.     

Alpha,beta: The rhythm of the attentional blink

Extant theories of the attentional blink propose that the most critical factor in determining second target accuracy is the time that elapses between the first and second targets. We report that this conclusion has overlooked an equally important determinant, namely, the frequency of the entraining stream in which these targets are embedded. Specifically, we show in two experiments that the signature of the attentional blink—second target accuracy that increases with intertarget lag—is significantly larger for entraining streams that are in the alpha-beta frequency range, relative to streams that are slower (theta) or faster (gamma). This finding ties the attentional blink critically, for the first time, to these two prominent oscillation frequencies that are known to be involved in the control of human attention and consciousness.     

The alpha -> beta polytypic transformation in SiC induced by ball milling

The alpha -> beta polytypic transformation in SiC was observed during ball milling at room temperature. Microstructural evolution was characterized on an atomic scale by high-resolution electron microscopy (HREM). HREM observations showed that partial dislocations play an important role in the transformation under the complicated conditions during ball milling.     

Stress and cardiac beta adrenoceptors

Most modern theories about stress recognize that although stress is not a disease, it may be the trigger for the majority of diseases when allostatic overload has been generated. During stress, the glucocorticoids and catecholamines play a key role in the regulation of physiological parameters and homeostasis during stress. In the heart, positive chronotropic, inotropic, and lusitropic responses to catecholamines are mediated by various subtypes of adrenergic receptors (beta-ARs), mainly beta1- and beta2-adrenergic receptors. beta-ARs also control cardiomyocyte growth and death, thus contributing to cardiac remodelling. The structural basis of each beta-AR subtype, as well as their signalling pathways, and adaptive responses to stress are discussed. The participation of beta3- and putative beta4-ARs in the control of cardiac function is also discussed, with emphasis on low affinity beta-AR isoforms and the role they play in the response to the catecholamines under stress. The changes in beta-AR signalling under pathogenic conditions as well as under stress are reviewed.     

The cognitive effects of trauma: reversal of alpha function and the formation of a beta screen

Following a brief review of Freud's writings on trauma, the author discusses relevant theories of Bion, and in particular the concepts of the alpha function and the beta screen. A clinical example is presented in which the patient's relatively recent trauma in adulthood had become fused with prior related experiences, leading to a propensity for repeated enactments in analysis and a failure to learn from experience. Drawing on the analyst's alpha function, the patient was gradually able to use mentalization to transform her rigidly structured traumatic organization. The author highlights the roles of dreams/dream associations and of screen memories in the patient's analysis.     

Some asymptotic properties of Luce's beta learning model

This paper studies asymptotic properties of Luce's beta model. Asymptotic results are given for the two-operator and four-operator cases of contingent and noncontingent reinforcement.This research was supported in part by the Group Psychology Branch of the Office of Naval Research and in part by the Rockefeller Foundation.     

On the use of beta coefficients in meta-analysis

This research reports an investigation of the use of standardized regression (beta) coefficients in meta-analyses that use correlation coefficients as the effect-size metric. The investigation consisted of analyzing more than 1,700 corresponding beta coefficients and correlation coefficients harvested from published studies. Results indicate that, under certain conditions, using knowledge of corresponding beta coefficients to input missing correlations (effect sizes) generally produces relatively accurate and precise population effect-size estimates. Potential benefits from applying this knowledge include smaller sampling errors because of increased numbers of effect sizes and smaller non-sampling errors because of the inclusion of a broader array of research designs.     

Probability-of-coverage tolerance intervals for the beta binomial

True score tolerance intervals, which are designed to cover a chosen proportion of the conditional distribution of true scores given an observed score, are suggested as alternatives to true score confidence intervals. Using large sample theory, a tolerance interval estimator for the beta binomial is derived. An example indicates that with moderate sample sizes, tolerance intervals with high probability of coverage will not be much wider than when the two beta true score parameters are known.The author acknowledges valuable comments from Richard Sawyer.Most work was completed while the author was at the American College Testing Program.     

Anterior-posterior beta asymmetries in dyslexia during lexical decisions

High-density EEG was recorded in 12 compensated dyslexics, 6 classified as dysphonetic and 6 as dyseidetic, and in 12 matched controls while they carried out a lexical-decision task. Relative to normal controls, dysphonetics showed higher beta power in anterior relative to posterior regions, while dyseidetics showed higher beta power in posterior relative to anterior regions. Further, controls (but not dyslexics) showed a positive correlation between performance on the task and the ratios of both left-to-right and anterior-to-posterior beta asymmetry. According to the dual-route theory of reading, there are two strategies that can be used in lexical decision: A visual strategy involving visual word identification and direct access to a visual lexicon, and a phonological strategy involving grapheme-to-phoneme conversion and access to a speech output lexicon. Our results therefore suggest compensation through weakness rather than strength, with phonological dyslexics focusing on a grapheme-to-phoneme strategy and dyseidetics focusing on visual word identification.     

The temporal sensitivity to the tactile-induced double flash illusion mediates the impact of beta oscillations on schizotypal personality traits

The coherent experience of the self and the world depends on the ability to integrate vs. segregate sensory information. Optimal temporal integration between the senses is mediated by oscillatory properties of neural activity. Previous research showed reduced temporal sensitivity to multisensory events in schizotypy, a personality trait linked to schizophrenia. Here we used the tactile-induced Double-Flash-Illusion (tDFI) to investigate the tactile-to-visual temporal sensitivity in schizotypy, as indexed by the temporal window of illusion (TWI) and its neural underpinnings. We measured EEG oscillations within the beta band, recently shown to correlate with the tDFI. We found individuals with higher schizotypal traits to have wider TWI and slower beta waves accounting for the temporal window within which they perceive the illusion. Our results indicate reduced tactile-to-visual temporal sensitivity to mediate the effect of slowed oscillatory beta activity on schizotypal personality traits. We conclude that slowed oscillatory patterns might constitute an early marker for psychosis proneness.     

Lithium tremor-combination treatment with beta receptor blockaders]

In addition to the various possibilities of influencing lithium tremor, experience gathered from the application of beta-receptor blockers is reported, and concepts investigated on the potential genesis and working mechanisms.     

Effects of beta blockade with metoprolol on simple and complex task performance

The effect of treatment with the beta-blocker metoprolol on several indicants of task performance was investigated. Twenty-five male hypertensives were treated for 2 weeks each with drug and placebo in a double-blind crossover design. Comparisons to 25 matched untreated normotensives were made. Participants responded twice to a Mood Adjective Check List (MACL) and the Stroop Color-Word Test. In addition, they participated in two parallel decision-making simulations. Normotensives and hypertensives on drug or placebo did not differ on MACL and Stroop scores. Comparisons on 12 validated simulation measures showed that drug treatment with metoprolol aided complex task performance. Drug treatment improved strategic capacity and the ability to deal effectively with emergencies. Preliminary evidence that treatment with metoprolol might help restore performance capacity that may have been lost due to hypertensive disease was also obtained.     

Effects of alpha and beta adrenergic antagonists on aggressive behavior in male mice

The effects of a variety of alpha and beta adrenergic antagonists were examined on the social encounters of isolated male mice with anosmic male partners. A range of alpha antagonists, including phentolamine, prazosin, and yohimbine, all suppressed social aggression. A range of beta antagonists, including propranolol, atenolol, metaprolol, and ICI 118, 551, also reduced this type of attack. Ethological assessment of the lowest effective dose of these adrenergic antagonists revealed a marked inhibitor action on offensive, social, and nonsocial behavior, while defensive responses and immobility were enhanced. It is concluded that the noradrenergic system has a significant non-specific role in mediating intermale aggression via both alpha and beta adrenergic receptor subtypes. © 1993 Wiley-Liss, Inc.     

Low doses of interleukin-1beta improve the leverpress avoidance performance of Sprague-Dawley rats

Recent research has indicated that the pro-inflammatory cytokines, particularly interleukin-1beta (IL-1beta), can affect learning and memory. We injected male Sprague-Dawley rats with IL-1beta (1.0, 3.0, or 6.0 microg/kg, i.p.) or saline vehicle, 24h before a single 4-h session of leverpress escape/avoidance conditioning. No effect of IL-1beta at any dose was observed in the number of escape responses across the 4-h session. However, subjects treated with the two lower doses (1.0 and 3.0 microg/kg) of IL-1beta performed more avoidance responses during the final hour of the 4-h session than the other two groups. Subjects treated with the highest dose of IL-1beta (6.0 microg/kg) did not differ from controls. Results are discussed in terms of the possible mechanisms behind the IL-1beta-induced enhancement of learning, as well as the observed dose-response relationship.     

An extended motor network generates beta and gamma oscillatory perturbations during development

This study examines the time course and neural generators of oscillatory beta and gamma motor responses in typically-developing children. Participants completed a unilateral flexion–extension task using each index finger as whole-head magnetoencephalography (MEG) data were acquired. These MEG data were imaged in the frequency-domain using spatial filtering and the resulting event-related synchronizations and desynchronizations (ERS/ERD) were subjected to voxel-wise statistical analyses to illuminate time–frequency specific activation patterns. Consistent with adult data, these children exhibited a pre-movement ERD that was strongest over the contralateral post-central gyrus, and a post-movement ERS response with the most prominent peak being in the contralateral precentral gyrus near premotor cortices. We also observed a high-frequency (∼80 Hz) ERS response that coincided with movement onset and was centered on the contralateral precentral gyrus, slightly superior and posterior to the beta ERS. In addition to pre- and post-central gyri activations, these children exhibited beta and gamma activity in supplementary motor areas (SMA) before and during movement, and beta activation in cerebellar cortices before and after movement. We believe the gamma synchronization may be an excellent candidate signal of basic cortical motor control, as the spatiotemporal dynamics indicate the primary motor cortex generates this response (and not the beta oscillations) which is closely yoked to the initial muscle activation. Lastly, these data suggest several additional neural regions including the SMA and cerebellum are involved in basic movements during development.     

Loss of coherency of the alpha/beta interface boundary in titanium alloys during deformation

The loss of coherency of interphase boundaries in two-phase titanium alloys during deformation was analyzed. The energy of the undeformed interphase boundary was first determined by means of the van der Merwe model for stepped interfaces. The subsequent loss of coherency was ascribed to the increase of interphase energy due to absorption of lattice dislocations and was quantified by a relation similar to the Read–Shockley equation for low-angle boundaries in single-phase alloys. It was found that interphase boundaries lose their coherency by a strain of approximately 0.5 at T = 800°C.