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In children, autotransplantation has been an accepted treatment alternative in the Scandinavian countries for decades in cases of agenesis or trauma. When working with children with rare syndromes, lack of teeth is often so pronounced that there are no teeth available for transplantation. Even so, sometimes there are retained teeth that can be transplanted! Here we present two patients with rare syndromes in which a retained tooth was transplanted. In both cases, neither the donor tooth nor the recipient site was ideal for transplantation. The first case is a girl with incontinentia pigmenti, 15 years old at the time of transplantation, and the second case is a boy with severe cherubism, aged 9.5 years at the time of transplantation. In the first case, a second molar with multiple roots retained at a mesial angle to the first molar in the upper jaw was transplanted to an infected site. In the second case, a retained first premolar in the upper jaw was transplanted to a cystic lesion. In both patients, the profit in the event of a successful transplantation was so great, that an attempt was made in spite of the negative circumstances. Both teeth were successfully transplanted and have been followed for more than 2 years with no ankylosis or pulp necrosis developing. We conclude that in a child with multiple missing teeth, the conventional rules of transplantation may be stretched. [ABSTRACT FROM AUTHOR]

BACKGROUND: Regional odontodysplasia, also described as ghost teeth, has been described on a number of occasions, in some cases generalized odontodysplasia affecting both the primary and the permanent dentition. However, generalised odontodysplasia is a very rare finding, involving large pulps and short roots of the whole dentition and in the cases previously reported the teeth finally erupt. In the case reported on herein this has not happened. CASE REPORT: A female patient, now aged 22-years-old, cared for in the TAKO-centre (Oslo) since she was 5 years old, presented with a continuing problem of absence of permanent teeth due to total lack of eruption. All her permanent teeth were either retained intra-alveolar or had been extracted following previous periods of pain and infections. There was no enamel on any of the permanent teeth and the dentine was softer than normal. In addition, there appeared to be very little potential for eruption. Hence, tooth development was affected in all aspects. Her skeletal height was much shorter than expected taking her tall parents into consideration. After all possible assessments, no specific diagnosis for the condition of this young woman has been determined. TREATMENT: Before the present series of dental care the patient was wearing full dentures in both jaws. In the autumn of 2007, implants were placed in her maxilla and an implant supported fixed prosthesis in porcelain was installed the following spring. Similarly, implants were placed in her mandible, partly in retained teeth, in the autumn of 2008, and an implant supported fixed prosthesis was inserted during the spring of 2009. FOLLOW-UP: after prosthetic treatment a dental hygienist has seen the patient regularly. No problems or signs of infections have occurred to date. CONCLUSION: This case report concerns a rare and apparently un-named syndrome affecting both primary and permanent teeth. This paper has been written with an aim of gathering the views as to the aetiology of her problem, hopefully finally to provide a definitive diagnosis. [ABSTRACT FROM AUTHOR]

By use of acoustic telemetry, the present study showed that both riverine anadromous brown trout (sea trout) Salmo trutta and Arctic charr Salvelinus alpinus in a north Norwegian river descended the river within the first 4 months after spawning in late September and spent long parts of the remaining winter period in the estuary and also possibly partly in salt water. This contradicts the general assumption, based on studies of lake-dwelling populations, that both species, and in particular S. alpinus, overwinter and spend 9–11 months in fresh water at northern latitudes and the rest of the year in salt water. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANNs) have been used widely for prediction and classification problems. In particular, many methods for building ANNs have appeared in the last 2 decades. One of the continuing important limitations of using ANNs, however, is their poor ability to analyze small data sets because of overfitting. Several methods have been proposed in the literature to overcome this problem. On the basis of our study, we can conclude that ANNs that use radial basis functions (RBFs) can decrease the error of the prediction effectively when there is an underlying relationship between the variables. We have applied this and other methods to determine the factors controlling and related to fracture spacing in the Lisburne formation, northeastern Alaska. By comparing the RBF results with those from other ANN methods, we find that the former method gives a substantially smaller error than many of the alternative methods. For example, the errors in predicted fracture spacing for the Lisburne formation with conventional ANN methods are approximately 50 to 200% larger than those obtained with RBFs. With a method that predicts fracture spacing more accurately, we were able to identify more reliably the effects on the spacing of such factors as bed thickness, lithology, structural position, and degree of folding. By comparing performances of all the methods we tested, we observed that some methods that performed well in one test did not necessarily do as well in another test. This suggests that, while RBF can be expected to be among the best methods, there is no "best universal method" for all the cases, and testing different methods for each case is required. Nonetheless, through this study, we were able to identify several candidate methods and, thereby, narrow the work required to find a suitable ANN. In petroleum engineering and geosciences, the number of data is limited in many cases because of expense or logistical limitations (e.g., limited core, poor borehole conditions, or restricted logging suites). Thus, the methods used in this study should be attractive in many petroleum-engineering contexts in which complex, nonlinear relationships need to be modeled by use of small data sets. [ABSTRACT FROM AUTHOR]