Fixation disparity: binocular vergence accuracy for a visual display at different positions relative to the eyes

Some observers do not fixate accurately at the point of regard: Their vergence angle (between the visual axes of the two eyes) may correspond to points slightly nearer or farther away. This vergence error, or fixation disparity, was measured with nonius (vernier) lines at six positions of a visual display relative to the eyes. At viewing distances of 40, 60, and 100 cm, the display was located either at eye level or at a downward inclination of gaze direction of -25 degrees relative to horizontal. Viewing conditions resembled typical office work. Lowering the screen induced a near shift in mean vergence response of 0.6 min arc, irrespective of viewing distance; the closer the screen, the more distant was the vergence response relative to the target (by 2.5 min arc on average). The slope of this proximity-fixation-disparity curve is an individual parameter of the vergence system. Actual or potential applications of this research include recommendations for the comfortable viewing distance of visual displays.     

Healthcare non-adherence decisions and internet health information

While the internet is emerging as an important transforming mechanism for health care and public health, questions remain about its limitations. Growing evidence indicates that a significant proportion of internet health information consumers is engaging treatment strategies inconsistent with professional recommendations. This study aimed to distinguish internet users who report non-adherence behavior from their counterparts based on several personal and environmental determinants. Using information obtained via the internet to refuse or discontinue treatment recommended by a doctor or dentist proved to be a widespread (11.2%) behavior. Internet health information bolstered non-adherence appears strongly linked with personal determinants such as anxiety, diminishing health, and gender – a pattern consistent with prior adherence research – and with environmental determinants including the perceived importance of both internet health information and internet-facilitated interpersonal interactions as well as using the internet as a social support vehicle.     

An evaluation of off-axis manual forces and upper extremity joint moments during unilateral pushing and pulling exertions

This study quantified changes in off-axis manual force production and upper extremity joint moments during sub-maximal one-handed push and pull tasks. Off-axis forces in the up/down and left/right directions were quantified in the presence or absence of constraints placed upon the direction of manual force application and/or arm posture. Resultant off-axis forces of 13.1% and 9.4% were produced for pulls and pushes, respectively. Off-axis forces during pulling were oriented downwards and to the right and were associated with a decreased should flexion moment when posture was constrained. Off-axis forces in the up/down direction were minimized with increased on-axis force level. Off-axis forces during pushing tended to be oriented to the left and were associated with increased elbow flexion moment when off-axis forces were allowed. By not accounting for these off-axis forces, we may not be accurately reflecting actionable muscle- and joint-level loading characteristics derived from biomechanically-based proactive ergonomics assessment approaches.

Practitioner Summary: Constrained arm postures and directions of manual force application influence the production of off-axis forces. As inaccurate estimation of true manual forces can markedly influence actionable outcomes of proactive ergonomic assessments, this study suggests that simplification of these estimates is insufficient and potentially misleading.     

Probabilistic neural network-based 2D travel-time tomography

Travel-time tomography for the velocity structure of a medium is a highly nonlinear and nonunique inverse problem. Monte Carlo methods are becoming increasingly common choices to provide probabilistic solutions to tomographic problems but those methods are computationally expensive. Neural networks can often be used to solve highly nonlinear problems at a much lower computational cost when multiple inversions are needed from similar data types. We present the first method to perform fully nonlinear, rapid and probabilistic Bayesian inversion of travel-time data for 2D velocity maps using a mixture density network. We compare multiple methods to estimate probability density functions that represent the tomographic solution, using different sets of prior information and different training methodologies. We demonstrate the importance of prior information in such high-dimensional inverse problems due to the curse of dimensionality: unrealistically informative prior probability distributions may result in better estimates of the mean velocity structure; however, the uncertainties represented in the posterior probability density functions then contain less information than is obtained when using a less informative prior. This is illustrated by the emergence of uncertainty loops in posterior standard deviation maps when inverting travel-time data using a less informative prior, which are not observed when using networks trained on prior information that includes (unrealistic) a priori smoothness constraints in the velocity models. We show that after an expensive program of network training, repeated high-dimensional, probabilistic tomography is possible on timescales of the order of a second on a standard desktop computer.

     

Validity of the Type A construct: A reprise.

The recent application of meta-analytic techniques to the topic of coronary proneness has proved useful in promoting a sound construct-validation approach, an approach that should have been used years ago. However, the meta-analytic methods and statistics themselves are subject to some degree of interpretation. This article explains and comments on some of the important conclusions and some key limitations that emerge from three recent meta-analyses of the Type A behavior pattern. Both methodological and conceptual issues are addressed. All in all, there is a remarkable degree of consensus about what we know and what we need to know. Strong evidence emerges that Type A behavior (assessed by the Structured Interview) is a significant risk factor for coronary heart disease, but the Type A construct still has not been adequately defined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuing dissemination of a school-based mental health program.

Reports survey findings based on the dissemination activities (1977–1981) of the Primary Mental Health Project, an innovative program model for early detection and prevention of school adjustment problems. Programs varied in professional and nonprofessional staffing patterns, screening procedures used, funding mechanisms, and day-to-day operating practices in ways that reflected districts' needs, populations served, and resources. The programs, however, shared 4 structural emphases: a focus on very young children, active early identification and screening, use of nonprofessional helpers to expand the reach of services, and development of new professional roles that catalyzed service delivery. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of the infraorbital nerve in retrieving behavior in lactating rats.

Studied the acute effect of perioral anesthesia on retrieval of pups in primiparous Wistar rats. Injecting lidocaine into the mystacial pads of Ss rendered the snout insensitive to touch and abolished Ss' ability to retrieve. In Exp I, injecting the drug into masseter muscles or ip did not render the snout anaptic or abolish retrieval, indicating that the effect of intramystacial lidocaine treatment could not be attributed to systemic toxicity or to the drug's spreading from mystacial pads to affect masseter muscles. In Exp II, cutting the infraorbital nerves produced temporary retrieval impairment that was indistinguishable from that produced by intramystacial lidocaine. The deficit was not due to postoperative debilitation. Infraorbital section did not interfere with the ability to locate and consume a piece of cheese. Cutting the facial nerves abolished vibrissal movement but did not disrupt retrieval. In Exp III, the possibility was tested that infraorbital deafferentation has a profound effect on retrieval because anaptic dams, in their initial attempts at picking up pups, elicit distress vocalizations from offspring. Ss injected with lidocaine in the mystacial pads failed to retrieve pups that had been anesthetized to abolish distress vocalizations. Thus, pup-produced vocalizations are not responsible for the retrieval impairment exhibited by anaptic mothers. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reinforcement of verbal affect responses of normal subjects during the interview.

"Twenty-six normal individuals, hospitalized for a variety of physical complaints, were interviewed for a period of 30 minutes. Each interview consisted of a 10-minute operant level period, during which E asked questions necessary to maintain S's talk but did not otherwise respond to S's speech; 10 minutes of conditioning, during which E reinforced by agreement all self-referred affect statements; and 10 minutes of extinction, during which E withheld all reinforcement. Conditioning of the verbal response class of self-referred affect statements occurred, and normal Ss showed greater resistance to extinction than did schizophrenics." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental manipulation of continuous speech in schizophrenic patients.

A method was developed for obtaining extended continuous speech samples from hospitalized schizophrenics. 1 group was reinforced for self-referred affect statements, 1 group for speech in general, and 1 group served as a no-reinforcement control. The effect of reinforcement proved specific to the response class reinforced, whether narrow (self-referred affect statements) or more general (total speech output). The conditioning process progresses from broad classes to the particular one on which reinforcement is contingent. The problem of respons-class identification and other implications of the findings are discussed. (36 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resonant Raman spectroscopy of nanotubes

Single and double resonances in Raman scattering are introduced and six criteria for the observation and identification of double resonances stated. The experimental situation in carbon nanotubes is reviewed in view of these criteria. The evidence for the D mode and the high-energy mode is found to be overwhelming for a double-resonance process to take place, whereas the nature of the radial breathing-mode Raman process remains undecided at this point. Consequences for the application of Raman scattering to the characterization of nanotubes are discussed.