77 research outputs found

    A chemotactic model for interaction of antagonistic microflora colonies: front asymptotics and numerical simulations

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    This paper studies a two-dimensional chemotactic model for two species in which one of them produces a chemo-repellent for the other. It is shown asymptotically and numerically how the chemical inhibits the invasion of a moving front for the second species and how stable steady states, which depend on the chemical concentration, can be reached. The results qualitatively explain experimental observations by Swain and Ray (Microbiol. Res. 164(2), 2009), where colonies of bacteria produce metabolite agents which prevent the invasion of fungi.Comment: New updated version: 24.04.2012. Substitutes previous version of 25.10.2011. New references added. Note a change in titl

    Epistemological and Innate in Kant and Chomsky

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    In this project, I aim to discuss some points of Kantian and Chomskyan theories of knowledge, pondering on connections between them. I propose the question “what are the epistemological connections between Kant and Chomsky?” using the comparative method. Besides an historical topic, I propose theoretical contents, as Chomskyan linguistics development; Kantian aprioristical thoughts; Kantian judgments and Port-Royal judgments; innate triangles for Kant, Chomsky and Descartes; and Chomsky’s linguistic on century 21st. The main objective of the article is to achieve a better understanding of Kant’s and Chomsky’s epistemic relations, in order to comprehend more about innateness and theory of knowledge in general.Keywords: Innateness. Cartesian Linguistics. Kant. Chomsky. Poverty of stimulus. DOI: https://doi.org/10.47295/mgren.v10i3.342

    Analysis of Polyphenols in the Lamiaceae Family by Matrix Solid-Phase Dispersion Extraction Followed by Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry Determination

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    Polyphenolic compounds (PCs) are natural-occurring secondary metabolites with considerable physiological and morphological importance in plants and different biological functions. In this work, a matrix solid-phase dispersion extraction/purification procedure, followed by an ultra-high-performance liquid chromatography–tandem mass spectrometry analysis, has been developed and validated for the quantification of 17 PCs in Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. from the Lamiaceae family. The use of a limited sample amount, combined with small solvent consumption, marks the convenience of this technique for the extraction/isolation of compounds of interest. The validation showed good results, with recoveries ranged between 75 and 105%, relative standard deviation values ≤12%, and very low matrix effects. The experimental results demonstrated the variability of the phenolic pattern of the samples and the need for accurate assessment of the phenolic pattern to establish the real nutra..

    Three-points interfacial quadrature for geometrical source terms on nonuniform grids

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    International audienceThis paper deals with numerical (finite volume) approximations, on nonuniform meshes, for ordinary differential equations with parameter-dependent fields. Appropriate discretizations are constructed over the space of parameters, in order to guarantee the consistency in presence of variable cells' size, for which LpL^p-error estimates, 1p<+1\le p < +\infty, are proven. Besides, a suitable notion of (weak) regularity for nonuniform meshes is introduced in the most general case, to compensate possibly reduced consistency conditions, and the optimality of the convergence rates with respect to the regularity assumptions on the problem's data is precisely discussed. This analysis attempts to provide a basic theoretical framework for the numerical simulation on unstructured grids (also generated by adaptive algorithms) of a wide class of mathematical models for real systems (geophysical flows, biological and chemical processes, population dynamics)

    A new clinical score for cranial CT in ED non-trauma patients: Definition and first validation.

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    Introduction:Well recognized guidelines are available for the use of cranial computed tomography (CCT) in traumatic patients,while no definitely accepted standards exists to for CCT in patientswithout history of head injury. The aimof this study is to propose an easy clinical score to stratify the need of CCT inemergency department (ED) patients with suspect non-traumatic intracranial pathology. Methods: We retrospectively evaluated patients presenting to the ED for neurological deficit, postural instability, acute headache, alteredmental status, seizures, confusion, dizziness, vertigo, syncope, and pre-syncope.Webuild a score for positive CCT prediction by using a logistic regression model on clinical factors significant at univariate analysis. The score was validated on a population of prospectively observed patients. Results: We reviewed clinical data of 1156 patients; positivity of CCT was 15.2%. Persistent neurological deficit, new onset acute headache, seizures and/or altered state of consciousness, and transient neurological disorders were independent predictors of positive CCT. We observed 508 patients in a validation prospective cohort; CCT was positive in 11.3%. Our score performed well in validation population with a ROC AUC of 0.787 (CI 95% 0.748\u20130.822). Avoiding CT in score 0 patients would have saved 82 (16.2%) exams. No patients with score 0 had a positive CCT findings; score sensitivity was 100.0 (CI 95% 93.7\u2013100.0). Conclusions: A score for risk stratification of patients with suspect of intra-cranial pathology could reduce CT request in ED, avoiding a significant number of CCT while minimizing the risk of missing positive results

    Phenotypic Characterization of EIF2AK4 Mutation Carriers in a Large Cohort of Patients Diagnosed Clinically With Pulmonary Arterial Hypertension.

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    BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 (BMPR2) are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene (EIF2AK4) are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH. METHODS: Whole-genome sequencing was performed on DNA from patients with idiopathic and heritable PAH and with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis recruited to the National Institute of Health Research BioResource-Rare Diseases study. Heterozygous variants in BMPR2 and biallelic EIF2AK4 variants with a minor allele frequency of <1:10 000 in control data sets and predicted to be deleterious (by combined annotation-dependent depletion, PolyPhen-2, and sorting intolerant from tolerant predictions) were identified as potentially causal. Phenotype data from the time of diagnosis were also captured. RESULTS: Eight hundred sixty-four patients with idiopathic or heritable PAH and 16 with pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis were recruited. Mutations in BMPR2 were identified in 130 patients (14.8%). Biallelic mutations in EIF2AK4 were identified in 5 patients with a clinical diagnosis of pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Furthermore, 9 patients with a clinical diagnosis of PAH carried biallelic EIF2AK4 mutations. These patients had a reduced transfer coefficient for carbon monoxide (Kco; 33% [interquartile range, 30%-35%] predicted) and younger age at diagnosis (29 years; interquartile range, 23-38 years) and more interlobular septal thickening and mediastinal lymphadenopathy on computed tomography of the chest compared with patients with PAH without EIF2AK4 mutations. However, radiological assessment alone could not accurately identify biallelic EIF2AK4 mutation carriers. Patients with PAH with biallelic EIF2AK4 mutations had a shorter survival. CONCLUSIONS: Biallelic EIF2AK4 mutations are found in patients classified clinically as having idiopathic and heritable PAH. These patients cannot be identified reliably by computed tomography, but a low Kco and a young age at diagnosis suggests the underlying molecular diagnosis. Genetic testing can identify these misclassified patients, allowing appropriate management and early referral for lung transplantation
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