The positional-specificity effect reveals a passive-trace contribution to visual short-term memory.

The positional-specificity effect refers to enhanced performance in visual short-term memory (VSTM) when the recognition probe is presented at the same location as had been the sample, even though location is irrelevant to the match/nonmatch decision. We investigated the mechanisms underlying this effect with behavioral and fMRI studies of object change-detection performance. To test whether the positional-specificity effect is a direct consequence of active storage in VSTM, we varied memory load, reasoning that it should be observed for all objects presented in a sub-span array of items. The results, however, indicated that although robust with a memory load of 1, the positional-specificity effect was restricted to the second of two sequentially presented sample stimuli in a load-of-2 experiment. An additional behavioral experiment showed that this disruption wasn't due to the increased load per se, because actively processing a second object--in the absence of a storage requirement--also eliminated the effect. These behavioral findings suggest that, during tests of object memory, position-related information is not actively stored in VSTM, but may be retained in a passive tag that marks the most recent site of selection. The fMRI data were consistent with this interpretation, failing to find location-specific bias in sustained delay-period activity, but revealing an enhanced response to recognition probes that matched the location of that trial's sample stimulus

Indian housing in the Marburg Port Shepstone sub-region.

Thesis (M.S.U.R.P.)-University of Natal, Durban, 1976.No abstract available

Sustainable society:wellbeing and technology - 3 case studies in decision making

Throughout history, technology has provided many and significant improvements to the way we live, but the current pace of development now often exceeds the ability for the full potential of any technological innovation to be explored and implemented before further innovations are introduced. This pace of change results both in missed opportunities for a technology in its ability to contribute to effective solutions in addressing issues such as reducing adverse environmental impact or improving the health of society. In considering the nature of technological innovation and development, the associated engineering design processes can themselves be characterized as being associated with a highly complex, iterative problem-solving exercises, involving the integration and synthesis of a wide range of technologies. This in turn requires the design team to manage trade-offs across a range of primary constraints, as for instance embodied energy in manufacturing, energy consumption in use, capital costs and operating and resource recovery costs. Further investigation into the complexity of societal issues and means for achieving a more effective and fuller utilization of both existing resources and technologies is necessary to place sustainability as a priority of the decision making process. To support discussion and provide context, three case studies are presented. The first case study examines a strategic framework adopting metrics aligned with environmental issues used as proxies for evaluating wellbeing and common good. The second case study examines the specific contribution of eHealth to wellbeing and the balance of technological, societal and political issues in determining outcomes. The third case study considers how technology might be embedded as part of the process of obtaining meta-data from within a small rural community to demonstrate the impact of mitigation strategies associated with the reduction of its carbon footprint, and hence on climate change. In doing so, the paper seeks to bring together issues surrounding environmental problems in relation to a technology driven engineering design process while positioning them in the context of social benefits arising from sustainable decision making.</p

Suppression of residual single-photon absorption relative to two-photon absorption in high finesse planar microcavities

Suppression of residual single-photon absorption (SPA) relative to two-photon absorption (TPA) in a high finesse GaAs planar microcavity is explored. The TPA photocurrent becomes larger than the SPA photocurrent as long as the incident continuous-wave optical power exceeds 0.09 mW. An optical power of 5 mW would be required if the relative SPA suppression did not exist

Wide Angle Decentered Lens Beam Steering for Infrared Countermeasures Applications

A beam-steering system consisting of three cemented achromatic doublets is presented. Intended for use in IR countermeasure applications, our system is designed to operate over the 2- to 5-μm spectrum with minimum angular dispersion. We show that dispersion can be minimized by using doublet lenses fashioned from AMTIR-1 and germanium. Our system is designed to be compact and lightweight, with no internal foci, while allowing steering to ±22.5 deg. We also maintain a minimum 2-in. clear aperture for all steering angles, and a nominal divergence of 1 mrad. Plane wave and Gaussian beam analyses of our system are presented

An Evaluation of The Effectiveness of Adaptive Histogram Equalization for Contrast Enhancement

Adaptive Histogram Equalization (AHE), a method of contrast enhancement which is sensitive to local spatial information in an image, has been proposed as a solution to the problem of the inability of ordinary display devices to depict the full dynamic intensity range in some medical images. This method is automatic, reproducible, and simultaneously displays most of the information contained in the grey-scale contrast of the image. However, it has not been known whether the use of AHE causes the loss of diagnostic information relative to the commonly-used method intensity windowing. In the current work, AHE and intensity windowing are compared using psychophysical observer studies. In studies performed at North Carolina Memorial Hospital, experienced radiologists were shown clinical CT images of the chest. Into some of the images, appropriate artificial lesion were introduced; the physicians were then shown the images processed with both AHE and intensity windowing. They were asked to assess the probability that as given image contained the artificial lesion, and their accurate was measured. The results of these experiments shown that for this particular diagnostic task, there was no significant difference in the ability of the two methods to depict luminance contrast; thus, further evaluation of AHE using controlled clinical trials is indicated

Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective

This essay is inspired by the ideas and research examined in the special section on “Stakeholder Marketing” of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing “prosociety” and “proenvironment” perspectives—orientations that are also in keeping with the public policy focus of this journal. Under the “hard form” of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society

Airway pressure release ventilation in mechanically ventilated patients with COVID-19: a multicenter observational study

Background Evidence prior to the coronavirus disease 2019 (COVID-19) pandemic suggested that, compared with conventional ventilation strategies, airway pressure release ventilation (APRV) can improve oxygenation and reduce mortality in patients with acute respiratory distress syndrome. We aimed to assess the association between APRV use and clinical outcomes among adult patients receiving mechanical ventilation for COVID-19 and hypothesized that APRV use would be associated with improved survival compared with conventional ventilation. Methods A total of 25 patients with COVID-19 pneumonitis was admitted to intensive care units (ICUs) for invasive ventilation in Perth, Western Australia, between February and May 2020. Eleven of these patients received APRV. The primary outcome was survival to day 90. Secondary outcomes were ventilation-free survival days to day 90, mechanical complications from ventilation, and number of days ventilated. Results Patients who received APRV had a lower probability of survival than did those on other forms of ventilation (hazard ratio, 0.17; 95% confidence interval, 0.03–0.89; P=0.036). This finding was independent of indices of severity of illness to predict the use of APRV. Patients who received APRV also had fewer ventilator-free survival days up to 90 days after initiation of ventilation compared to patients who did not receive APRV, and survivors who received APRV had fewer ventilator-free days than survivors who received other forms of ventilation. There were no differences in mechanical complications according to mode of ventilation. Conclusions Based on the findings of this study, we urge caution with the use of APRV in COVID-19

Linking Life Skills and Norms with adolescent substance use and delinquency in South Africa

We examined factors targeted in two popular prevention approaches with adolescent drug use and delinquency in South Africa. We hypothesized adolescent life skills to be inversely related, and perceived norms to be directly related to later drug use and delinquency. Multiple regression and a relative weights approach were conducted for each outcome using a sample of 714 South African adolescents ages 15 to 19 years (M = 15.8 years, 57% female). Perceived norms predicted gateway drug use. Conflict resolution skills (inversely) and perceived peer acceptability (directly) predicted harder drug use and delinquency. The “culture of violence” within some South African schools may make conflict resolution skills more salient for preventing harder drug use and delinquency.Department of HE and Training approved lis