Aggregation of chemotactic organisms in a differential flow

We study the effect of advection on the aggregation and pattern formation in chemotactic systems described by Keller-Segel type models. The evolution of small perturbations is studied analytically in the linear regime complemented by numerical simulations. We show that a uniform differential flow can significantly alter the spatial structure and dynamics of the chemotactic system. The flow leads to the formation of anisotropic aggregates that move following the direction of the flow, even when the chemotactic organisms are not directly advected by the flow. Sufficiently strong advection can stop the aggregation and coarsening process that is then restricted to the direction perpendicular to the flow

The role of procedural memory in grammar and numeracy skills

The objective of this study was to examine the contribution of procedural memory to grammar and numeracy skills, which both involve the manipulation of abstract patterns. Seventy-six typically developing children between 5 and 7 years of age were assessed on grammar with a past tense production task and a sentence comprehension task, on numeracy with a counting task and a calculation task, and on procedural memory with a serial reaction time task. Moderate correlations were found between the measures of grammar and numeracy. Moreover, 4 hierarchical linear regressions indicated that procedural memory was associated with calculation but not with counting or grammar skills when age and working memory were taken into account. These novel findings suggest that procedural memory may have a role to play in the development of some numeracy skills. Several possible explanations for the absence of contribution to grammar are considered

Communication aids in the classroom: the views of education staff and speech and language therapists involved with the Communication Aids Project

The findings presented in this paper are part of an independent evaluation study of the Communication Aids Project (CAP). The study was carried out between July 2003 and April 2004 and looked at the impact of CAP on children receiving communication aids and evaluated the CAP strategy of assessment and delivery. In this paper the views of education staff and speech and language therapists who were working with communication aid users in school are presented. The professionals who were interviewed provided positive feedback on the existence of CAP, on the assessment for the communication aid, particularly where the use of the aid in the classroom was considered, and on the children's increased participation in classroom and learning activities since receiving the aid. They also highlighted the issue of managing parents' expectations regarding the use of aids and the value of and need for continued training for professionals working with communication aids in the classroom. The authors of this article, Jannet Wright, senior lecturer, Chris Donlan, senior lecturer, Caroline Newton, lecturer, and Michael Clarke, lecturer, from University College London; Claire Lister, from the Institute of Child Health, London; and Jasmina Cherguit, assistant psychologist, draw upon their findings to develop recommendations for future policy, practice and professional development

Exploring the views of students on the use of Facebook in university teaching and learning

Facebook use among students is almost ubiquitous; however, its use for formal academic purposes remains contested. Through an online survey monitoring student use of module Facebook pages and focus groups, this study explores students’ current academic uses of Facebook and their views on using Facebook within university modules. Students reported using Facebook for academic purposes, notably peer–peer communication around group work and assessment – a use not always conceptualised by students as learning. Focus groups revealed that students are not ready or equipped for the collaborative style of learning envisaged by the tutor and see Facebook as their personal domain, within which they will discuss academic topics where they see a strong relevance and purpose, notably in connection with assessment. Students use Facebook for their own mutually defined purposes and a change in student mind- and skill-sets is required to appropriate the collaborative learning benefits of Facebook in formal educational contexts

Parents' expectations and perceptions concerning the provision of communication aids by the Communication Aids Project (CAP)

This paper reports findings from part of an evaluation study of the Communication Aids Project (CAP), a government-funded project in England which provided communication aids to school-aged children. The paper focuses on parents'views of the CAP process and the impact of the aid. Fourteen parents were interviewed twice over the telephone: once before or just as their children received communication aids and again six to eight weeks later. Parents expressed satisfaction with the impact of the aid on their children's lives and showed they had realistic expectations concerning potential short- and long-term benefits. They raised two main concerns regarding the provision of aids, namely the timescale involved and access to accurate information and advice

Communication aids in the classroom: the views of education staff and speech and language therapists involved with the Communication Aids Project

The findings presented in this paper are part of an independent evaluation study of the Communication Aids Project (CAP). The study was carried out between July 2003 and April 2004 and looked at the impact of CAP on children receiving communication aids and evaluated the CAP strategy of assessment and delivery. In this paper the views of education staff and speech and language therapists who were working with communication aid users in school are presented. The professionals who were interviewed provided positive feedback on the existence of CAP, on the assessment for the communication aid, particularly where the use of the aid in the classroom was considered, and on the children's increased participation in classroom and learning activities since receiving the aid. They also highlighted the issue of managing parents' expectations regarding the use of aids and the value of and need for continued training for professionals working with communication aids in the classroom. The authors of this article, Jannet Wright, senior lecturer, Chris Donlan, senior lecturer, Caroline Newton, lecturer, and Michael Clarke, lecturer, from University College London; Claire Lister, from the Institute of Child Health, London; and Jasmina Cherguit, assistant psychologist, draw upon their findings to develop recommendations for future policy, practice and professional development

Computerised speechreading training for deaf children: A randomised controlled trial

Purpose: We developed and evaluated in a randomised controlled triala computerised speechreading training programme to determine a) whether it is possible to train speechreading in deaf children and b) whether speechreading training results in improvements in phonological and reading skills.Previous studies indicate a relationship between speechreading and reading skill and further suggest this relationshipmay be mediated by improved phonological representations. This is important since many deaf children find learning to read to be very challenging. Method: Sixty-six deaf 5-7 year olds were randomised into speechreading and maths training arms. Each training programme was comprised of10 minutesessionsa day, 4 days a week for 12 weeks. Children were assessed on a battery of language and literacy measures before training, immediately after training, 3 months and 10 months after training. Results: We found no significant benefits for participants who completed the speechreading training, compared to those who completed the maths training, on the speechreading primary outcome measure. However, significantly greater gains were observed in the speechreading training group on one of the secondary measures of speechreading. There was also some evidence of beneficial effects of the speechreading training on phonological representations, however these effects were weaker. No benefits were seen toword reading. Conclusions: Speechreading skill is trainable in deaf children. However, to support early reading, training may need to be longer or embedded in a broader literacy programme. Nevertheless, a training tool that can improve speechreading is likely to be of great interest to professionals working with deaf children

Biofilms and device-associated infections.

Microorganisms commonly attach to living and nonliving surfaces, including those of indwelling medical devices, and form biofilms made up of extracellular polymers. In this state, microorganisms are highly resistant to antimicrobial treatment and are tenaciously bound to the surface. To better understand and control biofilms on indwelling medical devices, researchers should develop reliable sampling and measurement techniques, investigate the role of biofilms in antimicrobial drug resistance, and establish the link between biofilm contamination and patient infection

The Effect of Cell Death on the Stability of a Growing Biofilm

In this paper, we investigate the role of cell death in promoting pattern formation within bacterial biofilms. To do this we utilise an extension of the model proposed by Dockery and Klapper [13], and consider the effects of two distinct death rates. Equations describing the evolution of a moving biofilm interface are derived, and properties of steady state solutions are examined. In particular, a comparison of the planar behaviour of the biofilm interface in the different cases of cell death is investigated. Linear stability analysis is carried out at steady state solutions of the interface, and it is shown that, under certain conditions, instabilities may arise. Analysis determines that, while the emergence of patterns is a possibility in `deep’ biofilms, it is unlikely that pattern formation will arise in `shallow’ biofilms

Interactions between bacterial surfaces and milk proteins, impact on food emulsions stability

Bacteria possess physicochemical surface properties such as hydrophobicity, Lewis acid/base and charge which are involved in physicochemical interactions between cells and interfaces. Moreover, food matrices are complex and heterogeneous media, with a microstructure depending on interactions between the components in media (van der Waals, electrostatic or structural forces, etc.). Despite the presence of bacteria in fermented products, few works have investigated how bacteria interact with other food components. The objective of the present study was to determine the effects of the surface properties of lactic acid bacteria on the stability of model food emulsions. The bacteria were added to oil/water emulsions stabilized by milk proteins (sodium caseinate, whey proteins concentrate or whey proteins isolate) at different pH (from 3 to 7.5). The effect of bacteria on the emulsions stability depended on the surface properties of strains and also on the characteristics of emulsions. Flocculation and aggregation phenomena were observed in emulsion at pHs for which the bacterial surface charge was opposed to the one of the proteins. The effects of bacteria on the stability of emulsion depended also on the concentration of cations present in media such as Ca2+. These results show that the bacteria through their surface properties could interact with other compounds in matrices, consequently affecting the stability of emulsions. The knowledge and choice of bacteria depending on their surface properties could be one of the important factors to control the stability of matrices such as fermentation media or fermented products.Région Bourgogne, Agence Universitaire de la Francophonie