Gestalt Theory in Visual Screen Design — A New Look at an old subject

Although often presented as a single basis for educational visual screen design, Gestalt theory is not a single small set of visual principles uniformly applied by all designers. In fact, it appears that instructional visual design literature often deals with only a small set of Gestalt laws. In this project Gestalt literature was consulted to distil the most relevant Gestalt laws for educational visual screen design. Eleven laws were identified. They deal with balance/symmetry, continuation, closure, figure-ground, focal point, isomorphic correspondence, prŠgnanz, proximity, similarity, simplicity, and unity/harmony. To test the usefulness of these laws in visual screen design they were applied to the redesign of an instructional multimedia application, 'WoundCare', designed to teach nursing students wound management. The basic text-based screens in the original WoundCare application were replaced with graphical user interface screens, that were designed according to these principles. The new screen designs were then evaluated by asking students and others to compare the designs. The viewers were also asked to rate directly the value of using the eleven Gestalt design principles in the redesign, both for improving the product's appearance and improving its value for learning. The evaluation results were overwhelmingly positive. Both the new design and the value of applying the eleven Gestalt laws to improve learning were strongly supported by the students' opinions. However, some differences in the value of applying particular Gestalt laws to the interface design were identified and this forms a useful direction for future research

The Use of Software Design Patterns to Teach Secure Software Design: An Integrated Approach

Part 2: Software Security EducationInternational audienceDuring software development, security is often dealt with as an add-on. This means that security considerations are not necessarily seen as an integral part of the overall solution and might even be left out of a design. For many security problems, the approach towards secure development has recurring elements. Software design patterns are often used to address a commonly occurring problem through a “generic” approach towards this problem. The design pattern provides a conceptual model of a best-practices solution, which in turn is used by developers to create a concrete implementation for their specific problem. Most software design patterns do not include security best-practices as part of the generic solution towards the commonly occurring problem. This paper proposes an extension to the widely used MVC pattern that includes current security principles in order to teach secure software design in an integrated fashion

Comparative evaluation of a low cost ophthalmoscope (Arclight) for red reflex assessment among health care workers in Malawi

We compared the diagnostic performance and ease of use of a new solar powered low-cost Arclight direct ophthalmoscope (AO) to a more expensive traditional direct ophthalmoscope (TDO) (Keeler Professional V.2.8) in detecting abnormal red reflexes in simulated eyes. Both devices were used by 19 optometry students and 17 paediatric doctors based in the Kamuzu Central Hospital Campus in Lilongwe, Malawi. Participants examined four normal and four abnormal red reflexes using the two devices in random order. We scored the participants on their ability to identify clinical signs and make a diagnosis. Participants scored each device for ‘ease of use’. There was no statistically significant difference in diagnostic performance or ‘ease of use’ between the AO and the TDO when attempting to detect abnormal red reflexes in simulated eyes. We conclude that AO is an inexpensive yet equally effective alternative to the TDO in detecting red reflexes and due to its low cost, portability and consumable independence is well suited for use in low-income and middle-income countries.PostprintPeer reviewe

Impact of location on placentation in live tubal and cesarean scar ectopic pregnancies

INTRODUCTION: The objective of this study was to evaluate the impact of implantation outside the normal intra-uterine endometrium on development of the gestational sac. METHODS: We reviewed and compared the ultrasound measurements and vascularity score around the gestational sac in 69 women diagnosed with a live tubal ectopic pregnancy (TEP) and 54 with a cesarean scar ectopic pregnancy (CSP) at 6-11 weeks of gestation who were certain of their last menstrual period. RESULTS: The rate of a fetus with a cardiac activity in the study population was significantly (P < 0.001) higher in CSPs than in TEPs. The median maternal age, gravidity and parity were significantly (P =.005; P < 0.001 and P < 0.001, respectively) lower in the TEP than in the CSP group. The number of gestational sac size <5th centile for gestational age was significantly (P < 0.001) higher in the TEP than in the CSP group. There were no differences between the groups for the other ultrasound measurements. In cases matched for gestational age, the gestational sac size was significantly (P < 0.001) smaller in the TEP compared to the CSP group. There was a significant (P < 0.001) difference in the distribution of blood flow score with CSP presenting with higher incidence of moderate and high vascularity than TEP. DISCUSSION: Both TEP and CSP are associated with a higher rate of miscarriage than intrauterine pregnancies and the slow development of the gestation sac is more pronounced in TEPs probably as a consequence of a limited access to decidual gland secretions

Infection control and the significance of sputum and other respiratory secretions from adult patients with cystic fibrosis

BACKGROUND: There is limited data available on the environmental and public health impact of the microbiological hazards associated with sputa from patients with cystic fibrosis [CF]. Pseudomonas aeruginosa, Burkholderia cenocepacia (formerly Burkholderia cepacia genomovar III), Staphylococcus aureus and Stenotrophomonas maltophilia are bacterial pathogens which are commonly found in the sputum of CF patients. A study was performed to ascertain the amount of sputum produced relating to microbial loading, as well as the diversity of bacteria present in a population of adult patients, with particular attention to pathogenic organisms. METHODS: Sputum from adult [>18 years old] CF patients [n = 20], chosen randomly from a population of 138 CF patients, was collected over a 24 h period on admission to the in-patient CF unit and enumerated quantitatively, as well as the sputa from 138 adult CF patients was examined qualitatively for the presence of infecting microflora. In addition, all different phenotypes from the sputum of each patient were identified phenotypically employing a combination of conventional identification methods [e.g. oxidase], as well as the API Identification schemes [API 20 NE, API 20 E]. RESULTS: This study demonstrated that patients with cystic fibrosis generate large numbers of bacteria in their sputum, approximating to 10(9 )organisms per patient per day. Although these organisms are introduced to the environment from the respiratory tract mainly via sputum, relatively few represent true bacterial pathogens and therefore are not clinically important to the general public who are immunocompotent. The greatest risk of such environmental microbial loading is to other patients with CF and therefore CF patients should be made aware of the hazards of acquiring such organisms from the environment, as well as socializing with other CF patients with certain transmissible types, such as Pseudomonas aeruginosa and Burkholderia cenocepacia. CONCLUSIONS: Environmental health professionals should therefore be aware that CF patients are a greater risk to their peer grouping rather than to the general public or health care workers and that good personal hygiene practices with CF patients should be encouraged to minimize environmental contamination and potential acquistion

On Deusons or Deuteronlike Meson-Meson Bound States

The systematics of deuteronlike two-meson bound states, {\it deusons}, is discussed. Previous arguments that many of the present non-$q\bar q$ states are such states are elaborated including, in particular, the tensor potential. For pseudoscalar states the important observation is made that the centrifugal barrier from the P-wave can be overcome by the $1/r^2$ and $1/r^3$ terms of the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron-like $B\bar B^*$ and $B^*\bar B^*$ composites bound by approximately 50 MeV, while $D\bar D^*$ and $D^*\bar D^*$ states are expected near the threshold.Comment: Invited talk at the Hadron93 International Conf. on Hadron Spectroscopy, Como, Italy 22.-25.6. 1993. 5 pages in LATEX HU-SEFT R 1993-13

Cost-benefit analysis for commissioning decisions in GEO600

Gravitational wave interferometers are complex instruments, requiring years of commissioning to achieve the required sensitivities for the detection of gravitational waves, of order 10^-21 in dimensionless detector strain, in the tens of Hz to several kHz frequency band. Investigations carried out by the GEO600 detector characterisation group have shown that detector characterisation techniques are useful when planning for commissioning work. At the time of writing, GEO600 is the only large scale laser interferometer currently in operation running with a high duty factor, 70%, limited chiefly by the time spent commissioning the detector. The number of observable gravitational wave sources scales as the product of the volume of space to which the detector is sensitive and the observation time, so the goal of commissioning is to improve the detector sensitivity with the least possible detector down time. We demonstrate a method for increasing the number of sources observable by such a detector, by assessing the severity of non-astrophysical noise contaminations to efficiently guide commissioning. This method will be particularly useful in the early stages and during the initial science runs of the aLIGO and adVirgo detectors, as they are brought up to design performance.Comment: 17 pages, 17 figures, 2 table

Improving the Robustness of the Advanced LIGO Detectors to Earthquakes

Teleseismic, or distant, earthquakes regularly disrupt the operation of ground–based gravitational wave detectors such as Advanced LIGO. Here, we present EQ mode, a new global control scheme, consisting of an automated sequence of optimized control filters that reduces and coordinates the motion of the seismic isolation platforms during earthquakes. This, in turn, suppresses the differential motion of the interferometer arms with respect to one another, resulting in a reduction of DARM signal at frequencies below 100 mHz. Our method greatly improved the interferometers\u27 capability to remain operational during earthquakes, with ground velocities up to 3.9 μm s−1 rms in the beam direction, setting a new record for both detectors. This sets a milestone in seismic controls of the Advanced LIGO detectors\u27 ability to manage high ground motion induced by earthquakes, opening a path for further robust operation in other extreme environmental conditions