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Background. Orthodontic devices modify patient's occlusion but there is no consensus on the number, the distribution and the intensity of dental contact points characterising post-orthodontic treatment occlusion. This paper deals with the description of the morphological and functional problems related to it. The aim of this study is to propose a method correlating distribution, area and intensity of contact points with the activation of mandibular elevating muscles measured with standardized surface electromyography. Materials and methods. Five subjects without signs and symptoms of temporomandibular disorders which underwent orthodontic treatment were included in the study. Silicone impressions were taken for occlusal registration before and after treatment. Maximal voluntary clenching registrations were made with and without cotton rolls interposed between the dental arches, in order to standardise all potential as a percentage of clenching tests. Electromyographic indices (Percental Overlapping Coefficient (POC), asymmetry, activation, torque, impact) were recorded using a 4-channel electromyograph (EasyMyo®) before and after orthodontic treatment. Contact areas in the occlusal recordings were analysed with the method of trans-illumination to evaluate number, area and distribution of contacts. Results. In all cases, muscle activation indexes are normal. There is a slight decrease in POC of the temporalis (p ≤ 0.05). The activation index is positive in all the cases examined and increased after therapy (p ≤ 0.05). The Pearson correlation index between dental contacts symmetry and muscular activation symmetry was calculated and showed statistical relevance for the POC of the masseter (at 100 μm, p ≤ 0.05; 50 μm p ≤ 0.01) and for the mean POC (at 50 μm and 0 μm, p ≤ 0.05). Conclusions. The variation of the electromyographic indices is supposed to be a consequence of neuromuscular adaptations to the new occlusal morphology after orthodontic treatment, when both morphological and functional symmetry are needed. The variations of the electromyographic indices are in line with what is expected from the biological and functional point of view of the muscular activity. The illustrated method is valid and can be applied for further evaluation. [ABSTRACT FROM AUTHOR]

Introduction: The study of occlusion is fundamental in clinical practice. The methods commonly used for the analysis of the occlusion often provide only qualitative information, not very reliable, making these methods poorly reproducible. Purpose of the study: The aim of the study is the validation of a method for occlusal analysis in order to overcome the limits of existing techniques and guarantee an accurate analysis of the occlusion of patients. This method is based on the transillumination indices. Materials and methods: The method allows evaluating the extension of contact areas and contact points using ImageJ software, developed by NIH. Chips of the impression material at a different thickness (150, 100, 50 µm) have been considered. These chips are scanned. Dental occlusal registrations of 20 healthy patients were scanned and contacts points and areas have been measured at different thickness (150, 100, 50, <50, 0 µm). Results: The repeatability test demonstrated the validity of the method (technical error lower than 15%, except the measurements at 0 µm). Conclusions: It is possible to assert that this method is a promising and valid alternative to common techniques. Thanks to its reproducibility and objectivity it is possible to evaluate the quantitative data it provides about occlusal areas and contacts. [ABSTRACT FROM AUTHOR]

Few species of reptiles are known to establish stable social structures and among these, chelonians provided scarce and conflicting results. Moreover, studies on turtles are usually performed on adult individuals. In this study, we checked whether and when hatchlings of the European Pond Turtle ( Emys orbicularis galloitalica ) established stable hierarchical structures in their first year of life, whether hierarchies were stable in time and how steady they were. We also verified whether social ranks were associated to the individuals' size. We observed dyadic interactions daily within three small groups of turtles reared in a controlled environment for seven months. After two months, the hatchlings started to interact and progressively established stable hierarchical structures. However, the effectiveness of the three types of observed aggressive behaviors in reversing social ranks was low and the resulting hierarchies were flat. We did not find a significant effect of the turtles' size on their interactions' outcome and hierarchy structure. Our results provide clear evidence of the development and the characteristics of social behaviors in young reptiles in captivity. This study could be a starting point for investigating social structures in wild populations.

Background and Aim: The 38/2010 law has expanded the provision of palliative care to patients with chronic-degenerative diseases. The ISTAT data show that 60% of the dying population is suffering from these diseases and could, according to the literature review, benefit particularly from such treatments. This study investigates the point of view of healthcare professionals, working in the context of dementia, regarding the knowledge and application of palliative care in the field of dementia. The focus is on the analysis of the resistance that may prevent the spread of palliative care, slowing the application of such care in different settings of terminality., Methods: The method is a qualitative phenomenological approach. A grid of semi-structured interviews was created and was proposed to 33 health workers (18 women) who work in Health Centres or in the Alzheimer Nucleus of Northern Italy., Results: Most operators think they understand palliative care, they believe it to be useful and necessary, but often only connect it with terminal illness. Others have a broader vision based on a more abstract and theoretical level than on real practical knowledge. A majority of respondents think that the spread of palliative care is slow and difficult because of the prevalence of the biomedical model that holistically and prejudicially hinders the introduction of new models., Conclusion: Appropriate training is the fundamental key to overcoming resistance. The professionals interviewed showed that they were aware of their lack of knowledge and declared that they had little competence in managing the complexity of long-term pathologies.

Subsongs are vocal trials uttered by young birds to practice songs. Among songbirds, subsongs are displayed by individuals in their first year of life. Studies on Zebra Finches Poephila guttata suggest that the juveniles learn their songs from a vocal tutor, their father. In this study we examine the subsongs in six captive-born Meyer's Parrots Poicephalus meyeri, from fledging time to weaning. Recordings of songs from chicks and fathers were analyzed for similarities in frequency and time parameters. With age, the subsongs of the chicks became more similar to the vocalizations of the fathers with 20% similarity rating in the first week after fledging to 100% at weaning time. Moreover, fledged chicks were exposed to a wide range of stimuli from several species of parrots breeding pairs caged nearby but chicks exclusively learned their fathers' songs. Our data support the hypothesis that Meyer's Parrots are vocal learners and use their father as their tutor.

Garner found that observers judged the sensory ratio of 1:2 invalidly; however, it is possible that in Garner's experiment judgments were influenced by the different sets of variable stimuli used for the test. This paper reports an experiment designed to test the validity of the judged sensory ratio of 1:2 without using different sets of variable stimuli. Bipolar continua of brightness and darkness were used. Participants first adjusted a brightness so that it was the double of a standard brightness located between the middle and the black end of the brightness continuum and subsequently adjusted a brightness so that it was the double of this double (the quadruple of the original standard brightness), or adjusted a darkness so that it was the double of a standard darkness located between the middle and the white end of the darkness continuum and subsequently adjusted a darkness so that it was the double of this double (the quadruple of the original standard darkness). Participants reported quadruples of each standard even if such quadruples could not exist on the bipolar continuum. This confirms that participants judged the sensory ratio of 1:2 invalidly.

In patterns formed by two equally colored or by two transparent overlapping surfaces of different size that alternately appear in front of one another, the larger surface has a greater probability of appearing in front of the smaller surface. This effect is known as Petter's effect. The present study found that Petter's effect also occurred in patterns formed by colorless outlined surfaces. In these patterns Petter's effect was smaller than in chromatically homogeneous patterns. The results agree with the possibility that Petter's effect occurred in patterns formed by outlined surfaces because relative size was a cue to visually perceived distance.

Two overlapping transparent surfaces forming a two-dimensional pattern stand out in front of each other alternately. Let y denote the luminance of the region where these surfaces overlap and b the luminance of the background. In achromatic patterns, the probability that the lighter transparent surface appears to be in front of the other surface is known to increase with y and with b. The present results show that grouping by achromatic colour similarity cannot explain the effect of b. An alternative conjecture is that the luminance factors that control perceived surface segregation can explain the effects of y and b. Such an explanation predicts a new effect: the probability that one transparent surface appears to be in front increases with the absolute difference in luminance between the surface and the background. The present results confirm this prediction.

When an observer with a holistic viewing attitude perceives transparency in an achromatic two-dimensional pattern, some areas of the pattern form a single transparent phenomenal surface. In each of these areas the observer simultaneously perceives the gray color of the transparent surface and the gray color of the background that is visible through the transparent surface. With an analytic viewing attitude the observer perceives a single gray color in each area of the pattern. When the viewing attitude changes from analytic to holistic, the term color scission means the phenomenal replacement of the single analytically perceived gray color of an area of the pattern with the two gray colors that are perceived in the same area when such area forms a transparent surface. The concept of color scission has been used by Moore Heider and Metelli to explain phenomenal transparency. An analysis of experimental results reported in the literature shows that color scission does not occur in transparent patterns formed by only three areas and that it involves incorrect predictions of the occurrence of transparency in patterns formed by four or more areas. It is concluded that in general the concept of color scission is inadequate to explain phenomenal transparency.

Whether attention affects the estimated length of a line has been debated for a long time. Some authors have found estimated length to increase with attention; others have found that it decreased. The present study further investigated this problem with two experiments. The first confirmed that estimated length decreased with attention; however, this result had low reliability. The second experiment indicated that estimated length significantly decreased with attention for some participants and significantly increased for others. This finding accounts for the low reliability of the first experiment and for the conflicting results of previous studies. Implications of opposite effects of attention for models of sensory intensity are discussed. An interpretation of these effects in terms of response preferences is proposed.

It is presently unresolved whether lightnesses or differences in lightness are appropriate independent variables for models of perceived achromatic transparency. This experiment shows that differences in lightness rather than lightnesses affected the rated transparency and that local changes in differences in lightness altered the rated transparency locally. These results indicate that models of the perceived degree of transparency should be separately formulated for the different parts of a transparent surface and for the whole transparent surface. Two new models of the combined effects of lightness differences on the perceived transparency are proposed.

The study explored the luminance relations that determine the occurrence of achromatic transparency in phenomenal surfaces on complex backgrounds. Let the luminances of the left and right parts of a transparent surface on a bipartite background and those of the left and right parts of the bipartite background be p and q and m and n, respectively. Metelli proposed that this surface looks transparent when the rule p < q if m < n (or p > q if m > n) is satisfied, and Masin and Fukuda that it looks transparent when the inclusion rule is satisfied, that is, when p epsilon (m, q) or q epsilon (p, n). These rules also apply to achromatic checkerboards formed by one checkerboard enclosed in another checkerboard. This study shows that only the inclusion rule correctly predicted the occurrence of transparency in these checkerboards.

Petter's rule applies to two-dimensional patterns formed by two overlapping surfaces that alternatively appear in front of one another. It states that the surface with the shorter contours in the region where the surfaces look superimposed has a greater probability of appearing in front of the other surface. An experiment is reported the results of which show that Petter's rule is valid for chromatically homogeneous and for uniformly dense dotted patterns, and invalid for different kinds of chromatically inhomogeneous patterns. Petter's rule has been found to be valid when the overlapping surfaces have contours with gaps. It is proposed that Petter's rule derives from the dynamics of filling-in of contour gaps.

Fuchs's transparency occurs when the contour of a transparent surface encloses the contour of another surface located on an underlying homogeneous background. The luminance conditions of Fuchs's transparency have not yet been determined. Six experiments were designed to study this problem with achromatic two-dimensional patterns. An ellipse enclosing a coplanar square was briefly presented. It simulated the cast of an elliptical spotlight or shadow on the square. The duration of the ellipse, the luminance of the square before the ellipse appeared, and the luminance of two squares outside the ellipse did not substantially affect the probability of perceiving the ellipse as transparent. However, this probability varied largely with the single values of the stimulus luminance differences and with the order relations of the stimulus luminances. It is concluded that this local and global luminance information conditioned the occurrence of Fuchs's transparency in two-dimensional patterns.

The time the perceptual system takes to generate two overlapping phenomenal surfaces is estimated to be about 60 ms by a recognition task and 200-250 ms by a primed matching task. Here, a reaction-time task was used to test these estimates. It is plausible that when two overlapping phenomenal surfaces appear abruptly in the visual field the perceptual system sends a signal to the response system when the localisation of the parts of these surfaces begins. The perceptual system should send a subsequent signal when the phenomenal overlapping of the surfaces is achieved. The reaction times to these signals were estimated in two experiments. The difference between these estimates confirms the time estimate provided by the primed matching task.

In two experiments the luminance conditions for the occurrence of phenomenal transparency in achromatic flat patterns was studied. Let a, p, q and b be, respectively, the luminances of the parts A, P, Q, and B of a pattern comprising a transparent square on a two-part background, where P and Q are the parts of the square on backgrounds A and B, respectively. The results showed that magnitude of p-a, magnitude of q-b, and magnitude of p-q were quantitative conditions of transparency. Metelli has proposed two ordinal conditions of transparency, magnitude of a-b > magnitude of p-q and p > q if a > b (or p < q if a < b). Alternatively, Masin and Fukuda have proposed the single ordinal condition p [symbol: see text] (a, q) [or q [symbol: see text] (p,b)]. The results showed that this second condition best predicted the occurrence of transparency.

A single stimulus determined the alternative perceptions of an illusory transparent grey disk or of an internally illuminated circular hole. A square on a far background was visible through this disk or hole. Subjects rated the grey colour of the transparent disk or the phenomenal illumination inside the hole. The luminance difference relative to the transparent disk and the square and that relative to this disk and its background determined the probability of perceiving the transparent disk or the hole. Rated colour and illumination substantially depended only on this second difference. These results have implications for models of phenomenal transparency and illumination based on the idea that proximal contours activate neural representations of phenomenal attributes.

It is implicitly or explicitly assumed in current transparency models that all the parts of a completely transparent surface have the same perceived degree of transparency. In general, the two experiments reported here have shown that this assumption is false. Consequently, any general transparency equation based on this assumption is unjustified. Separate transparency equations for the different parts of a transparent surface are instead justified. This indicates the need for a model of the overall judgment of transparency of these parts. In the second experiment the hypothesis that the judged degree of transparency of a whole transparent surface is a weighted average of the judged degrees of transparency of the different parts of this surface was tested. The results contradict this hypothesis and support the idea that the judgment of transparency of a whole surface and that of its parts depend on different stimulus conditions.