Robustness of mutual information to inter-subject variability for automatic artefact removal from EEG

The externally recorded electroencephalogram (EEG) is contaminated with signals that do not originate from the brain, collectively known as artefacts. Thus, EEG signals must be cleaned prior to any further analysis. In particular, if the EEG is to be used in online applications such as Brain-Computer Interfaces (BCIs) the removal of artefacts must be performed in an automatic manner. This paper investigates the robustness of Mutual Information based features to inter-subject variability for use in an automatic artefact removal system. The system is based on the separation of EEG recordings into independent components using a temporal ICA method, RADICAL, and the utilisation of a Support Vector Machine for classification of the components into EEG and artefact signals. High accuracy and robustness to inter-subject variability is achieved.

Longitudinal investigation of the faecal microbiota of healthy full-term infants using fluorescence in situ hybridization and denaturing gradient gel electrophoresis.

From birth onwards, the gastrointestinal (GI) tract of infants progressively acquires a complex range of micro-organisms. It is thought that by 2 years of age the GI microbial population has stabilized. Within the developmental period of the infant GI microbiota, weaning is considered to be most critical, as the infant switches from a milk-based diet (breast and/or formula) to a variety of food components. Longitudinal analysis of the biological succession of the infant GI/faecal microbiota is lacking. In this study, faecal samples were obtained regularly from 14 infants from 1 month to 18 months of age. Seven of the infants (including a set of twins) were exclusively breast-fed and seven were exclusively formula-fed prior to weaning, with 175 and 154 faecal samples, respectively, obtained from each group. Diversity and dynamics of the infant faecal microbiota were analysed by using fluorescence in situ hybridization and denaturing gradient gel electrophoresis. Overall, the data demonstrated large inter- and intra-individual differences in the faecal microbiological profiles during the study period. However, the infant faecal microbiota merged with time towards a climax community within and between feeding groups. Data from the twins showed the highest degree of similarity both quantitatively and qualitatively. Inter-individual variation was evident within the infant faecal microbiota and its development, even within exclusively formula-fed infants receiving the same diet. These data can be of help to future clinical trials (e.g. targeted weaning products) to organize protocols and obtain a more accurate outline of the changes and dynamics of the infant GI microbiota.

Prosodie et Syndrome de Williams : une étude inter-langue

L’objectif de l’étude est de mieux cerner les particularités acoustiques de la prosodie d’enfants porteurs du SW de langue maternelle anglaise et de langue maternelle française. Des productions spontanées ont été recueillies à l’aide de la tâche de narration « Grenouille, où es-tu ? » (Mayer, 1969). La prosodie des enfants SW est comparée à celle de deux groupes typiques, un de même âge chronologique et un de même âge développemental que le groupe avec SW La population se compose de 1. 7 enfants SW de langue française âgés entre 6 ans et 13 ans 7 mois, appariés à deux groupes typiques et 2. 13 enfants SW de langue anglaise âgés entre 6 ans et 13 ans 11 mois, appariés à deux groupes typiques. Notre analyse porte sur un paramètre acoustique de la prosodie des enfants avec SW : la Variation de la Fréquence Fondamentale. Les résultats sont discutés sur les points suivants : 1. les différences et similitudes entre les profils prosodiques des enfants avec SW et des enfants typiques de même âge chronologique ou développemental, en langue anglaise et en langue française, 2. les différences entre les enfants avec SWde langue maternelle anglaise et les enfants avec SWde langue maternelle française et 3. le développement prosodique observé chez les enfants avec SW. (For English abstract see "Additional Information")

Inter-relationships between small, dense low-density lipoprotein (LDL), plasma triacylglycerol and LDL apoprotein B in an atherogenic lipoprotein phenotype in free-living subjects

A predominance of small, dense low-density lipoprotein (LDL) is a major component of an atherogenic lipoprotein phenotype, and a common, but modifiable, source of increased risk for coronary heart disease in the free-living population. While much of the atherogenicity of small, dense LDL is known to arise from its structural properties, the extent to which an increase in the number of small, dense LDL particles (hyper-apoprotein B) contributes to this risk of coronary heart disease is currently unknown. This study reports a method for the recruitment of free-living individuals with an atherogenic lipoprotein phenotype for a fish-oil intervention trial, and critically evaluates the relationship between LDL particle number and the predominance of small, dense LDL. In this group, volunteers were selected through local general practices on the basis of a moderately raised plasma triacylglycerol (triglyceride) level (>1.5 mmol/l) and a low concentration of high-density-lipoprotein cholesterol (<1.1 mmol/l). The screening of LDL subclasses revealed a predominance of small, dense LDL (LDL subclass pattern B) in 62% of the cohort. As expected, subjects with LDL subclass pattern B were characterized by higher plasma triacylglycerol and lower high-density lipoprotein cholesterol (<1.1 mmol/l) levels and, less predictably, by lower LDL cholesterol and apoprotein B levels (P<0.05; LDL subclass A compared with subclass B). While hyper-apoprotein B was detected in only five subjects, the relative percentage of small, dense LDL-III in subjects with subclass B showed an inverse relationship with LDL apoprotein B (r=-0.57; P<0.001), identifying a subset of individuals with plasma triacylglycerol above 2.5 mmol/l and a low concentration of LDL almost exclusively in a small and dense form. These findings indicate that a predominance of small, dense LDL and hyper-apoprotein B do not always co-exist in free-living groups. Moreover, if coronary risk increases with increasing LDL particle number, these results imply that the risk arising from a predominance of small, dense LDL may actually be reduced in certain cases when plasma triacylglycerol exceeds 2.5 mmol/l.

Model inter-comparison between statistical and dynamic model assessments of the long-term stability of blanket peat in Great Britain (1940-2099)

We compared output from 3 dynamic process-based models (DMs: ECOSSE, MILLENNIA and the Durham Carbon Model) and 9 bioclimatic envelope models (BCEMs; including BBOG ensemble and PEATSTASH) ranging from simple threshold to semi-process-based models. Model simulations were run at 4 British peatland sites using historical climate data and climate projections under a medium (A1B) emissions scenario from the 11-RCM (regional climate model) ensemble underpinning UKCP09. The models showed that blanket peatlands are vulnerable to projected climate change; however, predictions varied between models as well as between sites. All BCEMs predicted a shift from presence to absence of a climate associated with blanket peat, where the sites with the lowest total annual precipitation were closest to the presence/absence threshold. DMs showed a more variable response. ECOSSE predicted a decline in net C sink and shift to net C source by the end of this century. The Durham Carbon Model predicted a smaller decline in the net C sink strength, but no shift to net C source. MILLENNIA predicted a slight overall increase in the net C sink. In contrast to the BCEM projections, the DMs predicted that the sites with coolest temperatures and greatest total annual precipitation showed the largest change in carbon sinks. In this model inter-comparison, the greatest variation in model output in response to climate change projections was not between the BCEMs and DMs but between the DMs themselves, because of different approaches to modelling soil organic matter pools and decomposition amongst other processes. The difference in the sign of the response has major implications for future climate feedbacks, climate policy and peatland management. Enhanced data collection, in particular monitoring peatland response to current change, would significantly improve model development and projections of future change.

Estudo clínico-molecular na Leishmaniose mucocutânea diagnóstico e rastreamento de subpopulações de Leishmania (Viannia) braziliensis nos níveis inter e intrapacientes

O presente estudo teve como principal objetivo avaliar a diversidade genética de Leishmania (Viannia) braziliensis nos níveis inter e intrapacientes, diretamente em lesões cutâneas e mucosas de indivíduos com leishmanioses mucocutânea (LMC), disseminada (LD) e mucosa (LM), incluindo indivíduos coinfectados pelo vírus da imunodeficiência humana (HIV). Um total de 61 amostras procedentes de 38 pacientes foi analisado pelas técnicas da reação em cadeia da polimerase (PCR), da reação em cadeia da polimerase com primer único em condições de baixa estringência (LSSP-PCR) e da análise fenética, tendo como alvo molecular a região variável do minicírculo do DNA do cinetoplasto (kDNA). Neste estudo, predominaram indivíduos do sexo masculino e com acometimento mucoso nasal. A presença de DNA do parasita foi evidenciada pela banda diagnóstica de 750 pb, em todas as amostras analisadas, possibilitando o diagnóstico específico. Na investigação do perfil genotípico de subpopulações de L. (V.) braziliensis, através da LSSP-PCR, foi revelado o polimorfismo genético intrafragmento traduzido como uma assinatura do kDNA do parasito para cada amostra. Assinaturas de kDNAs similares em amostras de paciente coletadas ao mesmo tempo (mucosa oral e nasal), e a divergência nos perfis genéticos em amostras coletadas em tempos diferentes na mesma localização (mucosa nasal) sugerem a clonalidade do inóculo inicial, como consequência da estrutura populacional clonal de Leishmania No estudo da variabilidade genética de L. (V.) braziliensis nos níveis inter e intrapacientes foram evidenciadas similaridades genotípicas entre as amostras de lesões cutânea e mucosa intrapacientes. As análises fenética e estatística possibilitaram afirmar que a diversidade genética no nível intrapacientes é menor do que a observada entre os pacientes. Nenhuma associação pode ser observada entre os perfis genéticos de L. (V.) braziliensis e as formas clínicas da doença (LM, LMC, LD), e nem em relação à localização da lesão cutânea ou mucosa (nasal ou oral). O polimorfismo genético de L. (V.) braziliensis também foi evidenciado nos pacientes coinfectados pelo HIV, cuja análise fenética reuniu os perfis genéticos em dois grupos distintos, os quais discriminaram entre as amostras obtidas de pacientes com coinfecção Leishmania/ HIV daquelas obtidas de pacientes não coinfectados. A discriminação de perfis genéticos diferenciados de L. (V.) braziliensis em pacientes coinfectados pelo HIV sugere que a imunossupressão tem impacto na estrutura populacional do parasita. Os nossos resultados corroboram a complexidade genética existente nos parasitos do gênero Leishmania, reforçando a diversidade na dinâmica populacional e na plasticidade genética de L. (V.) braziliensis

The management of positive inter-store externalities in shopping centres: some empirical evidence

In enclosed shopping centres, stores benefit from the positive externalities of other stores in the centre. Some stores provide greater benefits to their neighbours than others – for example anchor tenants and brand leading stores. In managing shopping centres, these positive externalities might be captured through rental variations. This paper explores the determinants of rent – including externalities – for UK regional shopping centres. Two linked databases were utilised in the research. One contains characteristics of 148 shopping centres; the other has some 1,930 individual tenant records including rent level. These data were analysed to provide information on the characteristics of centres and retailers that help determine rent. Factors influencing tenant rents include market potential factors derived from urban and regional economic theory and shopping centre characteristics identified in prior retail research. The model also includes variables that proxy for the interaction between tenants and the impact of positive in-centre externalities. We find that store size is significantly and negatively related to tenant with both anchor and other larger tenants, perhaps as a result of the positive effects generated by their presence, paying relatively lower rents while smaller stores, benefiting from the generation of demand, pay relatively higher rents. Brand leader tenants pay lower rents than other tenants within individual retail categories.

Investigation of the faecal microbiota of kittens: monitoring bacterial succession and effect of diet

Weaning is a stressful process for kittens, and is often associated with diarrhoea and the onset of infectious diseases. The gastrointestinal microbiota plays an essential role in host well-being, including improving homeostasis. Composition of the gastrointestinal microbiota of young cats is poorly understood, and the impact of diet on the kitten microbiota unknown. The aims of this study were to monitor the faecal microbiota of kittens and determine the effect(s) of diet on its composition. Bacterial succession was monitored in two groups of kittens (at 4 and 6 weeks, and 4 and 9 months of age) fed different foods. Age-related microbial changes revealed significantly different counts of total bacteria, lactic acid bacteria, Desulfovibrionales, Clostridium cluster IX and Bacteroidetes between 4-week- and 9-month-old kittens. Diet-associated differences in the faecal microbiota of the two feeding groups were evident. In general, fluorescence in situ hybridization analysis demonstrated bifidobacteria, Atopobium group, Clostridium cluster XIV and lactic acid bacteria were dominant in kittens. Denaturing gradient gel electrophoresis profiling showed highly complex and diverse faecal microbiotas for kittens, with age- and/or food-related changes seen in relation to species richness and similarity indices. Four-week-old kittens harboured more diverse and variable profiles than those of weaned kittens.