Analysis of return distributions in the coherent noise model

The return distributions of the coherent noise model are studied for the system size independent case. It is shown that, in this case, these distributions are in the shape of q-Gaussians, which are the standard distributions obtained in nonextensive statistical mechanics. Moreover, an exact relation connecting the exponent $\tau$ of avalanche size distribution and the q value of appropriate q-Gaussian has been obtained as q=(tau+2)/tau. Making use of this relation one can easily determine the q parameter values of the appropriate q-Gaussians a priori from one of the well-known exponents of the system. Since the coherent noise model has the advantage of producing different tau values by varying a model parameter \sigma, clear numerical evidences on the validity of the proposed relation have been achieved for different cases. Finally, the effect of the system size has also been analysed and an analytical expression has been proposed, which is corroborated by the numerical results.Comment: 14 pages, 3 fig

The effect of low level laser on condylar growth during mandibular advancement in rabbits

<p>Abstract</p> <p>Introduction</p> <p>It has been shown that Low Level Laser (LLL) has a positive effect on bone formation. The aim of this study was to evaluate the effect of low level laser on condylar growth during mandibular advancement in rabbits.</p> <p>Materials and methods</p> <p>Continuous forward mandibular advancement was performed in fourteen male Albino rabbits with the mean age of 8 weeks and the mean weight of 1.5 ± 0.5 kg, with acrylic inclined planes. The rabbits were randomly assigned into two groups after 4 weeks. LLL (KLO3: wave length 630 nm) was irradiated at 3 points around the TMJ, through the skin in the first group. The exposure was performed for 3 minutes at each point (a total of 9 minutes) once a day for 3 weeks. The control group was not exposed to any irradiation. The rabbits in both groups were sacrificed after two months and the histological evaluation of TMJ was performed to compare fibrous tissue, cartilage, and new bone formation in condylar region in both groups. Disc displacement was also detected in both groups. Student's t-test, Exact Fisher and Chi square tests were used for the statistical analysis.</p> <p>Results</p> <p>The formation of fibrous tissue was significantly lower, while bone formation was significantly greater in lased group as compared with control group. The thickness of cartilage did not differ significantly between two groups.</p> <p>Conclusion</p> <p>Irradiation of LLL (KLO3) during mandibular advancement in rabbits, increases bone formation in condylar region, while neither increase in the cartilage thickness nor fibrous tissues was observed.</p

Evaluation of tooth number anomalies in a subpopulation of the North-East of Turkey

Objective: The aim was to evaluate the prevalence and distribution of tooth number anomalies in a Turkish subpopulation. Materials and Methods: A population of 2722 patients (1532 females and 1190 males; mean age, 12.33 ± 2.5 years) was retrospectively examined to determine the prevalence and distribution of the hypodontia, oligodontia, and hyperdontia using panoramic radiographs. All permanent teeth were investigated except thirds molars and the data obtained were recorded as unilateral (left or right) or bilateral according to gender. Pearson's Chi-squared and Fisher exact tests were used for difference comparisons (P < 0.05). Results: Permanent tooth anomalies were found in at least 132 (4.84%) of 2722 patients with no statistically difference between the genders, consists of 4.63% females and 5.12% males. Distribution of hyperdontia was statistically significant difference between genders, whereas distribution of hypodontia and oligodontia was no significant difference between genders. Hypodontia was the most frequently observed anomaly (3.67%), followed by hyperdontia (0.96%), and oligodontia (0.21%). Oligodontia and hypodontia were more frequent in females (3.98% and 0.26%, respectively), whereas hyperdontia was more frequently observed in males (1.68%). Maxillary lateral incisors were most common missing teeth (2.27%), while the frequency of hyperdontia was most common in premolars. Conclusion: The prevalence of teeth number anomalies was 4.84% of dental patients. Maxillary lateral incisors were most common missing teeth, while the frequency of hyperdontia was most common in premolars. © 2014 Dental Investigations Society