Universal window for two-dimensional critical exponents.

Two-dimensional condensed matter is realized in increasingly diverse forms that are accessible to experiment and of potential technological value. The properties of these systems are influenced by many length scales and reflect both generic physics and chemical detail. To unify their physical description is therefore a complex and important challenge. Here we investigate the distribution of experimentally estimated critical exponents, ß, that characterize the evolution of the order parameter through the ordering transition. The distribution is found to be bimodal and bounded within a window ∼0.1≤ß≤0.25, facts that are only in partial agreement with the established theory of critical phenomena. In particular, the bounded nature of the distribution is impossible to reconcile with the existing theory for one of the major universality classes of two-dimensional behaviour-the XY model with four-fold crystal field-which predicts a spectrum of non-universal exponents bounded only from below. Through a combination of numerical and renormalization group arguments we resolve the contradiction between theory and experiment and demonstrate how the 'universal window' for critical exponents observed in experiment arises from a competition between marginal operators.

Physical rehabilitation and burnout: different aspects of the syndrome and comparison between healthcare professionals involved.

AIM: The aim of this study is to investigate burnout syndrome among physical rehabilitation professionals focusing on the differences between 4 categories of healthcare professionals involved. METHODS: The experimental group consisted of 124 physiotherapy workers chosen among physicians, nurses, therapists, and technicians. The variables we chose to measure were: the presence of burnout (emotional exhaustion, depersonalization and lack of personal accomplishment), feelings of depression and anger, symptoms of psychological uneasiness and the level of perceived stress. RESULTS: Overall the level of burnout experienced was medium-low. Emotional exhaustion was more prevalent among physiotherapists, while depersonalization was higher among physicians. Moreover mild feelings of depression emerged among technicians. No differences were found among the 4 categories when feelings of anger were considered, although anger was present at different levels (and more or less expressed) throughout the working environment. CONCLUSIONS: Some considerations on the nature and possible causes of psychological distress emerged from the work carried out with the groups of healthcare professionals and some possible areas of intervention are suggested.

The Epibloc system for the treatment of wrist fractures.

The current prospective study was conducted to verify the results obtained in a heterogeneous group of 50 displaced fractures of the wrist treated with the Epibloc system. This method is simple and rapid to use and it does not require plaster. The results obtained are very satisfactory (good and excellent 91.6%) in AO type A2 and A3 fractures and in type C1 fractures (92.8%) and in C2 fractures (88.3%); in fractures with multiple fragments and compromise of the joint surface (C3) the results were not very significant because of the small number of lesions treated (4 cases), but they do not seem to differ very much from what was obtained by other authors when more complicated methods were used. The results were very unsatisfactory in type B fractures (Goyrand); it is our belief that this method is not indicated for lesions such as these, because of the intrinsic difficulty in monitoring dislocation of the volar metaepiphyseal fragment.

Pathologic fracture on bone cyst of the femoral neck treated by external fixator. Description of one case.

In 1993 a patient aged 16 years affected with pathologic fracture on bone cyst of the proximal femur came to our observation. The fracture and the cyst healed in 10 months after treatment using an external fixator and autoplastic bone grafts.

Occlusion and center of foot pressure variation: is there a relationship?

The influences of head and body posture on the mandibular rest position, the range of functional movements, and the initial tooth contact have been documented. In this investigation, the modifications of the position of the center of foot pressure during natural standing were studied in 30 women. The subjects were divided into three groups: healthy women (control), women with an asymmetric (unilateral) Angle class II malocclusion, and women with temporomandibular disorders. Data were acquired in 30-second trials by use of a force plate that allowed a separate assessment of each foot while the subjects maintained different dental positions: rest position; centric occlusion; maximum clench; occlusion on two cotton rolls placed on the mandibular teeth distal to the canines; and maximum clench on two cotton rolls. Bivariate analysis was used to compute the mean values and relevant variability for the center of foot pressure location during each trial. The results demonstrated that the modifications of foot center of pressure were not influenced by temporomandibular disorders and asymmetric malocclusion or by different dental positions.

Fourier analysis of cephalometric shapes.

Craniofacial growth and development involve both size and shape variations. Shape variations can be assessed independently from size using mathematical methods such as the Fourier series. A method for the reconstruction of outlines starting from selected landmarks and for their Fourier analysis has been developed and applied to analyze the age differences in shape in the tracings of the Bolton standards (lateral view) from 1 to 18 years of age. The size-independent shape of the Bolton standard at 18 years was larger at the chin, at the gonion, and in the anterior cranial base than the shape at 1 year of age. Conversely, the younger shape was larger in the middle part of face, corresponding roughly to the maxillary bone, than the older shape. When standardized for size, growth thus seemed to modify craniofacial shape with progressive lengthening and narrowing. This shape effect was largely overwhelmed by the very evident size increments, and it could be measured only using the proper mathematical methods.

Effect of growth and development on human soft tissue facial shape: a Fourier analysis.

Size plays a distorting role in the estimation of facial morphology, because it can mask more subtle shape differences. The conventional metric approach provides adequate quantitative information about size only, ignoring the problems of shape definition. Mathematical methods, such as the Fourier series, allow a correct quantitative analysis of shape and its changes. Methods to reconstruct outlines, starting from selected landmarks, and to allow Fourier analysis of these outlines have been developed. These techniques were applied to analyze the age and gender variations in shape of the soft tissue facial contour (frontal plane projection) in a group of 144 healthy children, aged 6 to 7 years and 9 to 10 years. The mean contours differed for both size and shape; Fourier analysis corrected for the size discrepancy and separated the contributions of size and shape to the global morphology. In particular, the sine component (asymmetry) of the soft tissue facial contour was influenced by both age and gender.