Indigenous demosponge spicules in a Late Devonian stromatoporoid basal skeleton from the Frasnian of Belgium

This paper records the first example of a demosponge spicule framework in a single specimen of a Devonian stromatoporoid from the Frasnian of southern Belgium. The small sample (2.5 × 2 cm) is a component in a brecciated carbonate from a carbonate mound in La Boverie Quarry 30 km east of Dinant. Because of the small size of the sample, generic identification is not confirmed, but the stromatoporoid basal skeleton is similar to the genus Stromatopora. The spicules are arranged in the calcified skeleton, but not in the gallery space, and are recrystallized as multi-crystalline calcite. The spicules fall into two size ranges: 10-20 μm diameter and 500-2000 μm long for the large ones and between 5-15 μm diameter and 50-100 μm length for the small ones. In tangential section, the spicules are circular, they have a simple structure, and no axial canal has been preserved. The large spicules are always monaxons, straight or slightly curved styles or strongyles. The spicules most closely resemble halichondrid/axinellid demosponge spicules and are important rare evidence of the existence of spicules in Palaeozoic stromatoporoids, reinforcing the interpretation that stromatoporoids were sponges. The basal skeleton may have had an aragonitic spherulitic mineralogy. Furthermore, the spicules indicate that this stromatoporoid sample is a demosponge. © 2014 Lethaia Foundation. Published by John Wiley & Sons Ltd

Attention-dependent modulation of cortical taste circuits revealed by granger causality with signal-dependent noise

We show, for the first time, that in cortical areas, for example the insular, orbitofrontal, and lateral prefrontal cortex, there is signal-dependent noise in the fMRI blood-oxygen level dependent (BOLD) time series, with the variance of the noise increasing approximately linearly with the square of the signal. Classical Granger causal models are based on autoregressive models with time invariant covariance structure, and thus do not take this signal-dependent noise into account. To address this limitation, here we describe a Granger causal model with signal-dependent noise, and a novel, likelihood ratio test for causal inferences. We apply this approach to the data from an fMRI study to investigate the source of the top-down attentional control of taste intensity and taste pleasantness processing. The Granger causality with signal-dependent noise analysis reveals effects not identified by classical Granger causal analysis. In particular, there is a top-down effect from the posterior lateral prefrontal cortex to the insular taste cortex during attention to intensity but not to pleasantness, and there is a top-down effect from the anterior and posterior lateral prefrontal cortex to the orbitofrontal cortex during attention to pleasantness but not to intensity. In addition, there is stronger forward effective connectivity from the insular taste cortex to the orbitofrontal cortex during attention to pleasantness than during attention to intensity. These findings indicate the importance of explicitly modeling signal-dependent noise in functional neuroimaging, and reveal some of the processes involved in a biased activation theory of selective attention

Um sistema nervoso conceitual para o diagnóstico neuropsicológico

Although tests are an important aspect of the neuropsychological practice, neuropsychology is not limited to nomothetically validated tests. The objective of this paper is to examine, from the perspective of a “conceptual nervous system”, meta-diagnostic aspects of neuropsychology, which go beyond testing. The nomothetic approach to diagnosis is compared to an idiographic one, in which diagnosis is conceived as hypothesis testing according to information processing models. The construction and use of these models is plausible due to the modular organization of the mental system, evidenced by double-dissociations. In this study, the diagnostic process in neuropsychology is examined, particularly the functional and topographic diagnoses. In most cases, the topographic diagnosis is only virtual, and uses the conceptual nervous system to correlate the observed functional deficit to lesional loci established in the literature. The models of information processing must be anatomically specified, since they will be used to establish structural-functional correlations. The human brain-mind can be seen as a computational system, in which cognition is located between perception (input) and action (output). Mental functions are divided into material (content possessing) and formal (organizers of mental processes). Brain lesions with different causes and locations disrupt these mental functions in different ways. The traditional nomothetic model of neuropsychological diagnosis must be complemented by an idiographic approach, testing hypotheses based on a model of structure-function correlation that is adequate to the anatomo-clinical relations observed in the different lesions. Key words: neuropsychology, structural-functional correlation, cognition.Apesar de a aplicação de testes, a partir de uma perspectiva nomotético- nomológica, constituir um aspecto importante da prática neuropsicológica, a neuropsicologia não se resume a esse procedimento. O objetivo deste trabalho é examinar, sob a perspectiva de um “sistema nervoso conceitual”, aspectos metadiagnósticos da neuropsicologia, cujos efeitos ultrapassam o uso de testes normatizados. Ao enfoque nomotético é contraposta a perspectiva idiográfica, na qual o diagnóstico é concebido como teste de hipóteses a partir de modelos de processamento de informação. A construção e o uso desses modelos é plausível devido à organização modular do sistema mental, evidenciada pelas duplas-dissociações. Neste trabalho, são analisados os processos de diagnóstico em neuropsicologia, principalmente o funcional e o topográfico. Na maioria das vezes, o diagnóstico de localização é virtual, e utiliza o sistema nervoso conceitual para relacionar o déficit funcional observado às localizações lesionais estabelecidas na literatura. Os modelos funcionais de processamento de informação devem ser anatomicamente especificados, para que possam ser usados como base para a correlação estrutura-função. O cérebro-mente humano pode ser visto como um sistema computacional; neste, a cognição se localiza entre a percepção (input) e a ação (output). As funções mentais são classificadas como materiais (com conteúdo) e formais (organização dos processos mentais). Lesões encefálicas com diferentes causas e localizações alteram essas funções de formas distintas. O modelo nomotético tradicional de diagnóstico neuropsicológico deve ser complementado por uma abordagem idiográfica, mediante a testagem das hipóteses baseadas num modelo de correlação estrutura-função que seja fiel às relações anátomo-clínicas observadas em diferentes lesões. Palavras-chave: neuropsicologia, correlação estrutura-função, cognição

Intradialytic hyperalimentation as adjuvant support in pregnant hemodialysis patients: case report and review of the literature

Pregnancy in chronic dialysis patients is unusual and associated with many complications. Infants are often born both prematurely and small for gestational age. We report a case of a 36-year-old diabetic hemodialysis patient G4P3 who had prolonged hyperemesis gravidarum, for whom intradialytic parenteral nutrition (IDPN) was started at week 14 and continued throughout her pregnancy. She delivered a 3.5-kg baby girl at the 36th week of gestation by cesarean section. We discuss the use of IDPN as adjunct therapy for pregnant dialysis patients

Time warping of evolutionary distant temporal gene expression data based on noise suppression

<p>Abstract</p> <p>Background</p> <p>Comparative analysis of genome wide temporal gene expression data has a broad potential area of application, including evolutionary biology, developmental biology, and medicine. However, at large evolutionary distances, the construction of global alignments and the consequent comparison of the time-series data are difficult. The main reason is the accumulation of variability in expression profiles of orthologous genes, in the course of evolution.</p> <p>Results</p> <p>We applied Pearson distance matrices, in combination with other noise-suppression techniques and data filtering to improve alignments. This novel framework enhanced the capacity to capture the similarities between the temporal gene expression datasets separated by large evolutionary distances. We aligned and compared the temporal gene expression data in budding (<it>Saccharomyces cerevisiae</it>) and fission (<it>Schizosaccharomyces pombe</it>) yeast, which are separated by more then ~400 myr of evolution. We found that the global alignment (time warping) properly matched the duration of cell cycle phases in these distant organisms, which was measured in prior studies. At the same time, when applied to individual ortholog pairs, this alignment procedure revealed groups of genes with distinct alignments, different from the global alignment.</p> <p>Conclusion</p> <p>Our alignment-based predictions of differences in the cell cycle phases between the two yeast species were in a good agreement with the existing data, thus supporting the computational strategy adopted in this study. We propose that the existence of the alternative alignments, specific to distinct groups of genes, suggests presence of different synchronization modes between the two organisms and possible functional decoupling of particular physiological gene networks in the course of evolution.</p