COLOR STABILITY OF DENTAL CERAMICS SUBMITTED TO ARTIFICIAL ACCELERATED AGING AFTER REPEATED FIRINGS

Statement of problem. Color stability is an important factor to ensure the long-term clinical success of ceramic restorations. There is a lack of information on how color is affected by fabrication procedures, such as the number of firings. Purpose. The purpose of this study was to evaluate the effects that the number of firings and type of substrate have on the color stability of dental ceramic submitted to artificial accelerated aging. Material and methods. Sixty specimens were fabricated: 30 metal ceramic (Verabond II + IPS d.SIGN) and 30 all-ceramic (IPS d.SIGN). Specimens were divided into 3 groups (n=10), and submitted to 2, 3, or 4 firings (+/- 900 degrees C), respectively, according to the manufacturer`s instructions. Color readings were obtained with a spectro photometer before and after artificial accelerated aging, and L*, a*, and b* coordinates and total color variation (Delta E) were analyzed (2-way ANOVA, Bonferroni, (alpha=05). Results. For metal ceramic specimens, differences for the L* coordinates were significant (P<.05) only for the group submitted to 3 firings. With respect to the all-ceramic specimens, smaller L* coordinates were obtained for greater a* and b* coordinates, indicating that the greater the number of firings, the darker and more reddish/yellowish the specimen. All Delta E values, for all groups, were below 1.0. All-ceramic specimens submitted to 3 and 4 firings presented Delta E means differing statistically (P<.05) from those of the metal ceramic group. Conclusions. The type of substrate and number of firings affected the color stability of the ceramic material tested. Artificial accelerated aging did not produce perceptible color stability changes (Delta E<1.0). (J Prosthet Dent 2009-101:13-18)

HIV/AIDS: use of the ICF in Brazil and South Africa - comparative data from four cross-sectional studies

Introduction Human immunodeficiency virus (HIV) is a serious disease which can be associated with various activity limitations and participation restrictions. The aim of this paper was to describe how HIV affects the functioning and health of people within different environmental contexts, particularly with regard to access to medication. Method Four cross-sectional studies, three in South Africa and one in Brazil, had applied the International Classification of Functioning, Disability and Health (ICF) as a classification instrument to participants living with HIV. Each group was at a different stage of the disease. Only two groups had had continuing access to antiretroviral therapy. The existence of these descriptive sets enabled comparison of the disability experienced by people living with HIV at different stages of the disease and with differing access to antiretroviral therapy. Results Common problems experienced in all groups related to weight maintenance, with two-thirds of the sample reporting problems in this area. Mental functions presented the most problems in all groups, with sleep (50%, 92/185), energy and drive (45%, 83/185), and emotional functions (49%, 90/185) being the most affected. In those on long-term therapy, body image affected 93% (39/42) and was a major problem. The other groups reported pain as a problem, and those with limited access to treatment also reported mobility problems. Cardiopulmonary functions were affected in all groups. Conclusion Functional problems occurred in the areas of impairment and activity limitation in people at advanced stages of HIV, and more limitations occurred in the area of participation for those on antiretroviral treatment. The ICF provided a useful framework within which to describe the functioning of those with HIV and the impact of the environment. Given the wide spectrum of problems found, consideration could be given to a number of ICF core sets that are relevant to the different stages of HIV disease. (C) 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Stacked central configurations for the spatial six-body problem

In this paper we show the existence of three new families of stacked spatial central configurations for the six-body problem with the following properties: four bodies are at the vertices of a regular tetrahedron and the other two bodies are on a line connecting one vertex of the tetrahedron with the center of the opposite face. (c) 2009 Elsevier B.V. All rights reserved.

Hanteringen när medarbetares privata problem inverkar negativt på arbetsplatsen : En studie ur ett ledarskapsperspektiv

Uppsatsens syfte var att undersöka hur ledare hanterar situationer där medarbetares privata problem inverkar negativt på arbetet för både arbetsgivare och övriga medarbetare. För att få svar på det har vi inspirerats av vinjettstudie som utgår från diskussioner av fiktiva fall. Vi har genomfört studien med fyra enskilda semistrukturerade intervjuer och en fokusgruppsintervju där vi först introducerade respondenterna med vinjetterna. Deltagarna till undersökningen valdes ut genom ett subjektivt urval där vi riktade in oss på ledare, angående vilken organisation de tillhörde var av mindre vikt. I teoridelen introducerades teorierna ledarskap, medarbetarskap, individen i gruppen, ekonomi, hälsa, lagar, organisationskultur och föreskrifter samt försäkringskassans roll. Resultatet analyserades sedan mot teorierna och vi kan konstatera att respondenterna generellt menade att det var viktigt att prioritera kommunikation och relationer. Betydelsefullt var att relationerna etablerades innan problemen uppstår eftersom det anses vara svårt att skapa relationer i konfliktfyllda lägen. Tiden har betydelse vid hantering av problem av den orsaken att gränsen för vad som är acceptabelt förflyttas med tidens gång. Beroende på problem varierade graden av toleransnivå hos chefer och övriga medarbetare i vår undersökning. Resultatet visade att gränsen för privatlivets påverkan på arbetslivet går när arbetet blir misskött och när kunder och andra medarbetare påverkas. Utifrån ett genusperspektiv ansåg intervjupersonerna att det saknade betydelse om chefen var en man eller kvinna när det handlade om att hantera problem som uppkom, det ansågs vara personligt.

The rough sets feature selection for trees recognition in color aerial images using genetic algorithms

Selecting a set of features which is optimal for a given task is the problem which plays an important role in a wide variety of contexts including pattern recognition, images understanding and machine learning. The concept of reduction of the decision table based on the rough set is very useful for feature selection. In this paper, a genetic algorithm based approach is presented to search the relative reduct decision table of the rough set. This approach has the ability to accommodate multiple criteria such as accuracy and cost of classification into the feature selection process and finds the effective feature subset for texture classification . On the basis of the effective feature subset selected, this paper presents a method to extract the objects which are higher than their surroundings, such as trees or forest, in the color aerial images. The experiments results show that the feature subset selected and the method of the object extraction presented in this paper are practical and effective.

Students perceptions of learning outcomes from group-based, problem-based teaching and learning activities

Objective: A study aimed at exploring the variation in perceptions of learning outcomes reported by undergraduate nursing students enrolled in a problem-based learning subject in a pre-registration Bachelor of Nursing course (BN).
Method: Students were asked to respond to four open-ended questions which focussed on their learning outcomes in the different teaching/learning modalities of the subject. Data were analysed in two phases using a modified phenomenographic analysis. In the first phase a set of categories of description were developed from the student responses to questions related to the learning modalities. In the second phase the individual responses were classified in terms of the categories. Finally, correlations between the learning modalities were identified. In this paper the approach to analysis, the process of category identification and the correlations between the learning modalities will be described and the implications for further research and teaching will be discussed.
Results: The findings indicated that there were two distinct groups of student responses. Inward focussed students who described outcomes in terms of their own learning and students whose focus was outward i.e. describing learning in terms of patient care and how learning relates to that care. Another important result shows the relationship between the learning modalities and outcomes. From the students' perspective, the most sophisticated outcomes of the lectures and laboratories were ideas and skills to be used and applied in clinical settings. Whereas, the group-based activities in which clinical problems were presented to the students in the form of Situation Improvement Packages (SIPS) focussed their attention on the clinical setting which constituted a preparation for the realities of clinical practice.
Conclusion: The findings from this study indicate that students perceive their learning in the group based teaching/learning modality (SIPS) as effective in focussing them on the reality of their role in the clinical practice environment while lectures and laboratories provided the skills and knowledge required for this setting.

Synoptic problem : an investigation of synoptic relationships

In recent years, the Synoptic Problem has become an important focus of New Testament scholarship. The Two-Document Hypothesis, although still widely accepted as the solution, has recently been challenged by a variety of source hypotheses, most notably the Griesbach hypothesis. In effect, the Synoptic Problem has become an open question for an increasing number of scholars. This project analyzes four significant pericopae, the Empty Tomb Tradition, the Kingdom Parables Discourse, the Synoptic Apocalypse, and the Transfiguration Narrative, in an attempt to determine priority and dependence among the synoptic Gospels. The study does not presuppose a particular source theory, although it does evaluate specific ones when applicable. The aim of the study is to conduct an analysis of a limited but representative amount of synoptic material in order to develop a working hypothesis concerning synoptic relationships.

The self concepts and possible selves of problem gamblers : a qualitative exploration

The study investigated the self-concepts and possible selves of pathological gamblers. Six female egm users were recruited from a Victorian problem gambling counselling service. Three participants were currently gambling and three were not gambling. They were interviewed in-depth and using thematic analysis four dominant themes were identified. (1) Self-concepts tended to be consistent across all participants, (2) having a past self as being the dominant characteristics of possible selves coincided with greater possible selves clarity, (3) non-gambler’s had more elaborate and specific plans for how to create change than did gambler’s, and (4) non-gambler’s had more plans to become possible selves which address goals of intrinsic meaning, rather then having a general goal to ‘not gamble’. The findings are discussed in terms of implications for the cognitive theory of possible selves and suggestions for further research to investigate the utility of the constructs as a basis for a treatment modality.

Readiness to change a problem behaviour : a conceptual framework

The thesis study aims to develop a model of readiness to enter treatment to change problem behaviour by addressing the limitations of previous models. The research shows that a model consisting of personal and social factors, mediated by problem recognition and desire for help accurately assesses readiness to enter treatment. The portfolio examines the broad framework of the Multifactor Offender Readiness Model (MORM) which assesses an offender's readiness to engage in treatment. Four case studies are presented.

Navigation of four-wheel-steering mobile robots using robust fault-tolerant sliding mode control

This paper addresses the leader-follower tracking problem of a four-wheel-steering robot subjected to nonlinear uncertainties. Two control laws have been developed, based on the adaptive sliding mode method and the adaptive input-output feedback linearization method. The proposed control schemes have been tested by means of simulations.

Estimating prey accessibility for waders : a problem still to be solved

Estimating the accessible prey fraction for short-billed waders, we used a new sampling device - the sediment- plane( Desholme t al. 1998) - to record prey density of the uppermost benthos communities in softbottom habitats. In contrast to "ordinary"core-samplers, the sediment plane allows a relatively quick sampling of the uppermost layers of the sediment and, thus, it should allow a more reliable estimate of the accessible benthos community especially of vertically mobile prey organisms such as polychaetes. To assess its usefulness, we compared samples collected with the sediment-plane that took only the uppermost 3cm of the sediment with samples taken with a core-sampler. These investigations showed significant differences between the two sampling methods. In comparison with the corresponding layer of the core samples, we found significantly higher numbers and a higher biomass for at least four polychaete species (e.g. Ragworm Nereis diversicolor) in the plane samples.Therefore, we recommend the use of the sediment-plane when studying the accessible fraction for foraging waders especially when studying short-billed species.

One image reduction algorithm for RGB color images

We investigate the problem of combining or aggregating several color values given in coding scheme RGB. For this reason, we study the problem of averaging values on lattices, and in particular on discrete product lattices. We study the arithemtic mean and the median on product lattices. We apply these aggregation functions in image reduction and we present a new algorithm based on the minimization of penalty functions on discrete product lattices.

Robust fault-tolerant leader-follower control of four-wheel-steering mobile robots using terminal sliding mode

This paper addresses the actuator failure compensation problem of non-linear fourwheel-steering mobile robots based on vehicle kinematics, undergoing both known and unknown failures causing degenerated steering performance or wheels stuck at some observable angles. Terminal sliding mode control technique is used to guarantee the tracking stability infinite time with the presence of actuator fault. Simulation results are given to illustrate the effectiveness of the proposed control scheme. © Institution of Engineers Australia 2012.

A proof of concept for using brief Dialectical Behavior Therapy as a treatment for problem gambling

Fourteen ‘treatment resistant’ problem gamblers received 9 weeks of Dialectical Behavior Therapy (DBT) at specialist problem gambling services delivered in Melbourne, Australia. This study is the first to investigate the effectiveness of a brief DBT treatment for problem gambling, with a focus on measuring change in the four DBT process skills (mindfulness, distress tolerance, emotion dysregulation, and negative relationships). Although there were no statistically significant improvements in measures of gambling behaviour, 83% of participants were abstinent or reduced their gambling expenditure pre- to post-treatment. Participants also reported statistically and clinically significant improvements in psychological distress,  mindfulness, and distress tolerance. Moreover, there were no increases in alcohol or substance use. These results are discussed in the context of focusing on a single DBT process skill, and the benefits of using group-based approaches.