Mild Head Injury: Criteria for Computed Tomography Scan

Background/Objective: Mild Head Injury (MHI) is the most commontype of head trauma, and forms a majority of the injuries seen in the traumaunit (65-85%).1 This study was aimed at using previously identifiedclinical risk factors to determine which category of patients with MHIwould not need to undergo Computed Tomography (CT). This may serveas cost saving measure to patients and hospitals likewise reduce collectiveradiation dose to the population.Methodology: A retrospective study conducted at the trauma unit of ateaching hospital situated in the Cape Metropole. CT scan images of 50patients aged 14 years and above who had MHI and undergone CTexamination were retrieved from the archive. Patients’ information, clinicalhistory and resultant CT findings were collated. Clinical risk factors werecorrelated with abnormal and normal CT scan findings. Data wereanalyzed using chi-square statistic at 95% confidence interval.Results: Twenty three (46%) of the patients had abnormal CT findings,and all presented with one or more of these risk factors; severe headache(10%), skull fracture (20%), scalp injury (6%), loss of consciousness(LOC)(8%) and intoxication(2%). The results were not statisticallysignificant when compared with the normal CT scans group. Four patients(8%) with no risk factors had normal CT scans. All the patients presentingwith the clinical risk factors, of nausea and vomiting 6% (n=50), seizures4% (n=50) had normal CT scan findings.Conclusion: Certain clinical risk factors can be used to suggest theprobability of abnormal CT scan in patients with MHI. Patients with norisk factors such as patients with confusion and disorientation are morelikely to have normal CT findings and may therefore be exempted from CTexamination. Further studies with larger sample size may be helpful invalidating these findings

The WACDT, a modern vigilance task for network defense

Vigilance decrement refers to a psychophysiological decline in the capacity to sustain attention to monotonous tasks after prolonged periods. A plethora of experimental tasks exist for researchers to study vigilance decrement in classic domains such as driving and air traffic control and baggage security; however, the only cyber vigilance tasks reported in the research literature exist in the possession of the United States Air Force (USAF). Moreover, existent cyber vigilance tasks have not kept up with advances in real-world cyber security and consequently no longer accurately reflect the cognitive load associated with modern network defense. The Western Australian Cyber Defense Task (WACDT) was designed, engineered, and validated. Elements of network defense command-and-control consoles that influence the trajectory of vigilance can be adjusted within the WACDT. These elements included cognitive load, event rate, signal salience and workload transitions. Two forms of the WACDT were tested. In static trials, each element was adjusted to its maximum level of processing difficulty. In dynamic trials, these elements were set to increase from their minimum to their maximum values. Vigilance performance in static trials was shown to improve over time. In contrast, dynamic WACDT trials were characterized by vigilance performance declines. The WACDT provides the civilian human factors research community with an up-to-date and validated vigilance task for network defense accessible to civilian researchers

A review of cyber vigilance tasks for network defense

The capacity to sustain attention to virtual threat landscapes has led cyber security to emerge as a new and novel domain for vigilance research. However, unlike classic domains, such as driving and air traffic control and baggage security, very few vigilance tasks exist for the cyber security domain. Four essential challenges that must be overcome in the development of a modern, validated cyber vigilance task are extracted from this review of existent platforms that can be found in the literature. Firstly, it can be difficult for researchers to access confidential cyber security systems and personnel. Secondly, network defense is vastly more complex and difficult to emulate than classic vigilance domains such as driving. Thirdly, there exists no single, common software console in cyber security that a cyber vigilance task could be based on. Finally, the rapid pace of technological evolution in network defense correspondingly means that cyber vigilance tasks can become obsolete just as quickly. Understanding these challenges is imperative in advancing human factors research in cyber security

Mapping between cognitive theories and psycho-physiological models of attention system performance

Declines in the capacity to sustain attention to repetitive, monotonous tasks is a phenomenon known as vigilance decrement (Endsley M, Kiris E. The out-of-the-loop performance problem and level of control in automation. 1995. Hum Factors. 37:32-64). This review compares cognitive theories with psycho-physiological models of vigilance decrement, and a gap is identified in mapping between the 2. That is, theories of vigilance decrement refer to cognitive resources; by contrast, psychophysiological models of the cerebral systems associated with attention explain performance functions according to neurochemical resources. A map does not currently exist in the literature that bridges the gap between cognitive theories of vigilance decrement and psychophysiological models of the human attention system. The link between cognitive resource theories of vigilance decrement and the psychophysiological models of attention performance is a gap in the literature that this review fills. This comprehensive review provides an expanded psychophysiological understanding of vigilance decrement that could help inform the management of declines in sustained attention capacity in operational settings. In addition, elucidating the link between cognitive theories of vigilance decrement and psychophysiological models of the human attention system might be used to treat and better understand pathologies such as attention-deficit hyperactivity disorder

Normative influence on retirement savings decisions: Do people care what employers and the government want?

The need for Australians to increase retirement savings has been widely promoted. Yet our understanding of the motivations of individuals to save at a higher rate remains sparse. This article reports the findings of a survey of superannuation fund members and their intentions to contribute more to superannuation and to manage their investment strategy. The article uses the theory of planned behaviour to focus on the important motivational influence of social norms. Formative research identified a number of influential social referents. Among identified referents, the study found that spouses appear to be the primary source of social influence for retirement savings decisions. The government and employers appear to exert little influence, and financial advisors and superannuation funds take up the middle ground of social influence. Possibilities for interventions designed to influence behaviour are discussed; however, conclusions are tempered by the fact that correspondence between intention and behaviour is not tested in the present research

Electronic couplings for singlet fission:Orbital choice and extrapolation to the complete basis set limit

For the search for promising singlet fission candidates, the calculation of the effective electronic coupling, which is required to estimate the singlet fission rate between the initially excited state (S 0S 1) and the multiexcitonic state ( 1TT, two triplets on neighboring molecules, coupled into a singlet), should be sufficiently reliable and fast enough to explore the configuration space. We propose here to modify the calculation of the effective electronic coupling using a nonorthogonal configuration interaction approach by: (a) using only one set of orbitals, optimized for the triplet state of the molecules, to describe all molecular electronic states, and (b) only taking the leading configurations into consideration. Furthermore, we also studied the basis set convergence of the electronic coupling, and we found, by comparison to the complete basis set limit obtained using the cc-pVnZ series of basis sets, that both the aug-cc-pVDZ and 6–311++G** basis sets are a good compromise between accuracy and computational feasibility. The proposed approach enables future work on larger clusters of molecules than dimers

Expanding and Testing a Computational Method for Predicting the Ground State Reduction Potentials of Organic Molecules on the Basis of Empirical Correlation to Experiment

A method for predicting the ground state reduction potentials of organic molecules on the basis of the correlation of computed energy differences between the starting S-0 and one-electron-reduced D-0 species with experimental reduction potentials in acetonitrile has been expanded to cover 3.5 V of potential range and 74 compounds across 6 broad families of molecules. Utilizing the conductor-like polarizable continuum model of implicit solvent allows a global correlation that is computationally efficient and has improved accuracy, with r(2) \u3e 0.98 in all cases and root mean square deviation errors of(mean absolute deviationsmV) for either B3LYP/6-311+G(d,p) or B3LYP//6-31G(d) with an appropriate choice of radii (UAKS or UA0). The correlations are proven to be robust across a wide range of structures and potentials, including four larger (27-28 heavy atoms) and more conformationally flexible photochromic molecules not used in calibrating the correlation. The method is also proven to be robust to a number of minor student mistakes or methodological inconsistencies