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Fractal-driven distortion of resting state functional networks in fMRI: a simulation study
No full textFractals are self-similar and scale-invariant patterns found ubiquitously in nature. A lot of evidences implying fractal properties such as 1/f power spectrums have been also observed in resting state fMRI time series. While the traditional model of fractal behavior in resting state fMRI has been a fractional Gaussian noise, it is limited to describe the physical implication of fractal behavior on functional connectivity of the brain. To answer this problem, we have proposed the fractal-based model of resting state hemodynamic response function (rs-HRF) whose properties can be summarized by a fractal exponent. Here we show, through a simulation studies, that the fractal behavior of cerebral hemodynamics may cause significant distortion of network properties between neuronal activities and BOLD signals. We simulated neuronal population activities based on the stochastic neural field model from the Macaque brain network, and then obtained their corresponding BOLD signals by convolving them with the rs-HRF filter. The precision of centrality estimated in each node was deteriorated overall in three networks based on transfer entropy, mutual information, and Pearson correlation; particularly the distortion of transfer entropy was more sensitive to the standard deviation of fractal exponents. A node with high centrality was resilient to desynchronized fractal dynamics over all frequencies while a node with small centrality exhibited huge distortion of both wavelet correlation and centrality over low frequencies. This theoretical expectation indicates that the difference of fractal exponents between brain regions leads to discrepancy of statistical network properties, especially at nodes with small centrality, between neuronal activities and BOLD signals, and that the traditional definitions of resting state functional connectivity may not effectively reflect the dynamics of spontaneous neuronal activities. As an alternative, the nonfractal connectivity, which is defined as the correlation of nonfractal components of resting state BOLD signals, can be considered to overcome the fractal artifact. In conclusion, our simulation studies may give us insight into the influence of fractal behavior on complex networks of the brain
Atherosclerosis of Coronary Arteries as Predisposing Factor in Myocardial Infarction: An Autopsy Study.
No full textThe incidence of coronary heart disease has markedly increased in India over the past few years. Ischemic heart disease, the largest cause of morbidity and mortality in the developed and developing countries today is overwhelmingly contributed by atherosclerosis. The study highlights the impact of atherosclerotic lesions in the population of Rajkot district. We studied atherosclerotic lesions in coronary arteries in cases subjected to autopsy in last 4 years, to grade and to evaluate the atheromatous plaques; and to assess the cases of myocardial infarction amongst them. The study comprises dissected specimens of heart in total 360 cases subjected for autopsy. The vessels were examined for the presence of atherosclerotic lesions which were graded according to American Heart Association and examined for evidence of myocardial infarction. The study comprises the cases in age group between 20 to 80 years. Commonest type of atherosclerosis seen was grade-4. Left Anterior Descending Coronary was most commonly involved artery. Myocardial infarction was the cause of death in 35 cases (9.72%) The data obtained may form a baseline for the forthcoming studies
Complex Problem Solving
No full textComplex problem solving takes place for reducing the\ud
barrier between a given start state and an intended goal\ud
state with the help of cognitive activities and behavior.\ud
Start state, intended goal state, and barriers prove\ud
complexity, change dynamically over time, and can be\ud
partially intransparent. In contrast to solving simple\ud
problems, with complex problems at the beginning of\ud
a problem solution the exact features of the start state,\ud
of the intended goal state, and of the barriers are\ud
unknown. Complex problem solving expects the effi-\ud
cient interaction between the problem-solving person\ud
and situational conditions that depend on the task.\ud
It demands the use of cognitive, emotional, and\ud
social resources as well as knowledge
The Problem of the Relationships of Love, Hate and Indifference
No full textIn Franceschi (2002), I presented a theory based on the matrices of concepts aiming at providing an alternative to the classification proposed by Greimas, in the field of paradigmatic analysis. The problem of specifying the relationships of the concepts of love, hate and indifference, arises in this construction. I attach myself to describe the problem of the love-hate-indifference relationships in detail, and several solutions that have been proposed to solve it. Finally I expose a solution to this problem, based on an extension of the theory of matrices of concepts
Qualitative analysis of academic group and discussion forum on Facebook
No full textIn the present study, data was triangulated and two methods of data analysis were used. Qualitative analysis was undertaken of free-text data from students’ reflective essaysto extract socially-related themes. Heuristic evaluation was conducted by expert evaluators, who investigated forum contributions and discourse in line with contemporary learning theory and considered the social\ud
culture of participation. Findings of the qualitative analysis of students’ perceptions and results of the\ud
heuristic evaluation of forum participation confirmed each other, indicating a warm social climate and a conducive, well-facilitated environment that supported individual styles of participation. It fostered interpersonal relationships between distance learners, as well as study-related benefits enhanced by peer teaching and insights acquired in a culture of social negotiation. The environment was effectively moderated, while supporting student-initiative.\u
Fractal analysis of resting state functional connectivity of the brain
No full textA variety of resting state neuroimaging data tend to exhibit fractal behavior where its power spectrum follows power-law scaling. Resting state functional connectivity is significantly influenced by fractal behavior which may not directly originate from neuronal population activities of the brain. To describe the fractal behavior, we adopted the fractionally integrated process (FIP) model instead of the fractional Gaussian noise (FGN) since the FIP model covers more general aspects of fractality than the FGN model. We also introduce a novel concept called the nonfractal connectivity which is defined as the correlation of short memory independent of fractal behavior, and compared it with the fractal connectivity which is an asymptotic wavelet correlation. We propose several wavelet-based estimators of fractal connectivity and nonfractal connectivity for a multivariate fractionally integrated noise (mFIN). The performance of these estimators was evaluated through simulation studies and the analyses of resting state functional MRI data of the rat brain
The Process of Solving Complex Problems
No full textThis article is about Complex Problem Solving (CPS), its history in a variety of research domains (e.g., human problem solving, expertise, decision making, and intelligence), a formal definition and a process theory of CPS applicable to the interdisciplinary field. CPS is portrayed as (a) knowledge acquisition and (b) knowledge application concerning the goal-oriented control of systems that contain many highly interrelated elements (i.e.,\ud
complex systems). The impact of implicit and explicit knowledge as well as systematic strategy selection on the solution process are discussed, emphasizing the importance of (1) information generation (due to the initial intransparency of the situation), (2) information reduction (due to the overcharging complexity of the problem’s structure), (3) model building (due to the interconnectedness of the variables), (4) dynamic decision making (due to the eigendynamics of the system), and (5) evaluation (due to many, interfering and/or ill-defined goals)
Language as literature: Characters in everyday spoken discourse
No full textThere are several linguistic phenomena that, when examined closely, give evidence that people speak through characters, much like authors of literary works do, in everyday discourse. However, most approaches in linguistics and in the philosophy of language leave little theoretical room for the appearance of characters in discourse. In particular, there is no linguistic criterion found to date, which can mark precisely what stretch of discourse within an utterance belongs to a character, and to which character. And yet, without at least tentatively marking the division of labor between the different characters in an utterance, it is absolutely impossible to arrive at an acceptable interpretation of it. As an alternative, I propose to take character use seriously, as an essential feature of discourse in general, a feature speakers and listeners actively seek out in utterances. I offer a simple typology of actions in discourse that draws on this understanding, and demonstrate its usefulness for the analysis of a conversation transcript
Granulocytic Sarcoma as the First Sign of Acute Leukemia in Childhood
No full textAcute myeloid leukemia (AML) may rarely involve the orbit as a solid tumor termed granulocytic sarcoma. This report describes the case of a child who presented with rapidly progressive unilateral proptosis and was diagnosed as rhabdomyosarcoma. However subsequent examination of the peripheral blood film revealed AML. Thus proptosis may present as the initial manifestation of AML
Explosive Pleuritis
No full textPleural effusions associated with pneumonia (parapneumonic effusions) are one of the most common causes of exudative pleural effusions in the world. Approximately 20 to 40% of patients hospitalized with pneumonia will have an accompanying pleural effusion. The term 'Explosive pleuritis' was originally described by Braman and Donat in 1986 as pleural effusions developing within hours of admission. We report a 38 years old male patient with minimal pleural effusion which progressed rapidly within one day to involve almost whole of the hemithorax. There were multiple loculations on ultrasonography of thorax. Pleural fluid was sero-sanguinous and revealed gram positive diplococcic. The patient improved with antibiotics and pigtail catheter drainage