Diagnosis and management of unusual dental abscesses in children

Although the majority of dental abscesses in children originate from dental caries or trauma, a few are associated with unusual conditions which challenge diagnosis and management. Recent research findings have shed light on these unusual entities and greatly improved understanding of their clinical implications. These conditions include developmental abnormalities such as dens invaginatus in which there is an invagination of dental tissues into the pulp chamber and dens evaginatus in which a tubercle containing pulp is found on the external surface of a tooth crown. In addition, inherited conditions which show abnormal dentine such as dentine dysplasia, dentinogenesis imperfecta, and osteogenesis imperfecta predispose the dentition to abscess formation. Furthermore, 'spontaneous' dental abscesses are frequently encountered in familial hypophosphataemia, also known as vitamin D-resistant rickets, in which there is hypomineralization of dentine and enlargement of the pulp. In addition to developmental conditions, there are also acquired conditions which may cause unusual dental abscesses,. These include pre-eruptive intracoronal resorption which was previously known as 'pre-eruptive caries' or the 'fluoride bomb'. In addition, some undiagnosed infections associated with developing teeth are now thought to be the mandibular infected buccal cysts which originate from infection of the developing dental follicles. In the present paper, these relatively unknown entities Which cause unusual abscesses in children are reviewed with the aim of updating the general practitioner in their diagnosis and management.

Is the effect of reading misspellings context dependent?

In 48 university students performing single-item spelling recognition, prior exposure to misspelled words improved slightly the accuracy on correctly spelled words and increased markedly the 'false alarm' rate (classifying a misspelling seen at study as correct). In a group given a dictation test (N = 24) the only effect of exposure to misspellings was a small increment in the number of misspellings that matched the misspelling seen at study. The two test groups showed no advantage of having the same display format at study and test (AA or BB vs AB or BA). Experiment 2 (in progress) investigated a format match at study and test against a condition with a new test context (AA or BB vs AC or BC). The results to date suggest an influence of memory of the study trial rather than simply an updating by the study exposures of abstract lexical representations. [ABSTRACT FROM AUTHOR]

Cervical Cancer Control, Priorities and New Directions

Cervical cancer is caused by infection with a range of high risk oncogenic human papillomavirus (HPV) types, and it is now accepted that >99% of cervical cancer is initiated by HPV infection. The estimated lifetime risk of cervical cancer is nevertheless relatively low (less than I in 20 for most community based studies). Although sensitivity and specificity of the available diagnostic techniques are suboptimal, Screening for persistent HPV infection is effective in reducing the incidence of cervical cancer. Infection can be detected by molecular techniques or by cytological examination of exfoliated cervical cells. Persistent infection is the single best predictor of risk of cervical cancer.(1) The latest findings of HPV and cervical cancer research need to be widely disseminated to the scientific and medical societies that are updating screening and management protocols, public health professionals, and to women and clinicians. This report reviews current evidence, clinical implications and directions for further research in the prevention, control and management of cervical cancer. We report the conclusions of the Experts' Meeting at the EUROGIN 2003 conference. (C) 2003 Wiley-Liss, Inc.

Using BWW model to evaluate building ontologies in CGs formalism

The Bunge-Wand-Weber (BWW) representation model defines ontological constructs for information systems. According to these constructs the completeness and efficiency of a modeling technique can be defined. Ontology plays an essential role in e-commerce. Using or updating an existing ontology and providing tools to solve any semantic conflicts become essential steps before putting a system online. We use conceptual graphs (CGs) to implement ontologies. This paper evaluates CG capabilities using the BWW representation model. It finds out that CGs are ontologically complete according to Wand and Weber definition. Also it finds out that CGs have construct overload and construct redundancy which can undermine the ontological clarity of CGs. This leads us to build a meta-model to avoid some ontological-unclarity problems. We use some of the BWW constructs to build the meta-model. (c) 2004 Elsevier Ltd. All rights reserved.

Position information but not force information is used in adapting to changes in environmental dynamics

This study investigated how movement error is evaluated and used to change feedforward commands following a change in the environmental dynamics. In particular, we addressed the question of whether only position-error information is used or whether information about the force-field direction can also be used for rapid adaptation to changes in the environmental dynamics. Subjects learned to move in a position-dependent force field (PF) with a parabolic profile and the dynamics of a negative spring, which produced lateral force to the left of the target hand path. They adapted very rapidly, dramatically reducing lateral error after a single trial. Several times during training, the strength of the PF was unexpectedly doubled (PF2) for two trials. This again created a large leftward deviation, which was greatly reduced on the second PF2 trial, and an aftereffect when the force field subsequently returned to its original strength. The aftereffect was abolished if the second PF2 trial was replaced by an oppositely directed velocity-dependent force field (VF). During subsequent training in the VF, immediately after having adapted to the PF, subjects applied a force that assisted the force field for similar to 15 trials, indicating that they did not use information about the force-field direction. We concluded that the CNS uses only the position error for updating the internal model of the environmental dynamics and modifying feedforward commands. Although this strategy is not necessarily optimal, it may be the most reliable strategy for iterative improvement in performance.

Breeding Rice for Drought-Prone Environments

A large portion of the world’s poor farm in rainfed systems where the water supply is unpredictable and droughts are common. In Asia, about 50% of all the rice land is rainfed and, although rice yields in irrigated systems have doubled and tripled over the past 30 years, only modest gains have occurred in rainfed rice systems. In part, this is because of the difficulty in improving rice varieties for environments that are heterogeneous and variable, and in part because there has been little effort to breed rice for drought tolerance. Information available for other cereals (for example, maize, Bänziger et al 2000) and for wheat and the limited or circumstantial evidence available for rice indicate that we can now breed varieties that have improved yield under drought and produce high yields in the good seasons. This manual aims to help plant breeders develop such varieties. While the manual focuses on drought tolerance, this must be integrated with the mainstream breeding program that also deals with agronomic adaptation, grain quality, and pest and disease resistance. Mackill et al (1996) have written a guide to the overall improvement of rice for rainfed conditions. This manual should be seen as an amplification of and updating of the section on drought tolerance in that book. Because final proof of many approaches for breeding drought-tolerant rice is not yet available, and because some aspects may not work in all environments and germplasm, we recommend that you use this manual with caution. Test the suggested approaches and only implement them on a large scale if they are effective and realistic for your own situation

Playing in continuous spaces: Some analysis and extension of population-based incremental learning

As an alternative to traditional evolutionary algorithms (EAs), population-based incremental learning (PBIL) maintains a probabilistic model of the best individual(s). Originally, PBIL was applied in binary search spaces. Recently, some work has been done to extend it to continuous spaces. In this paper, we review two such extensions of PBIL. An improved version of the PBIL based on Gaussian model is proposed that combines two main features: a new updating rule that takes into account all the individuals and their fitness values and a self-adaptive learning rate parameter. Furthermore, a new continuous PBIL employing a histogram probabilistic model is proposed. Some experiments results are presented that highlight the features of the new algorithms.