622 research outputs found
Directed Percolation Universality in Asynchronous Evolution of Spatio-Temporal Intermittency
We present strong evidence that a coupled-map-lattice model for
spatio-temporal intermittency belongs to the universality class of directed
percolation when the updating rules are asynchronous, i.e. when only one
randomly chosen site is evolved at each time step. In contrast, when the system
is subjected to parallel updating, available numerical evidence suggests that
it does not belong to this universality class and that it is not even
universal. We argue that in the absence of periodic external forcing, the
asynchronous rule is the more physical.Comment: 12 pages, RevTeX, includes 6 figures, submitted to Physical Review
Letters; changed version includes a better physical motivation for
asynchronous updates, extra references and minor change
Trigeminal neuralgia: new classification and diagnostic grading for practice and research
Trigeminal neuralgia (TN) is an exemplary condition of neuropathic facial pain. However, formally classifying TN as neuropathic pain based on the grading system of the International Association for the Study of Pain is complicated by the requirement of objective signs confirming an underlying lesion or disease of the somatosensory system. The latest version of the International Classification of Headache Disorders created similar difficulties by abandoning the term symptomatic TN for manifestations caused by major neurologic disease, such as tumors or multiple sclerosis. These diagnostic challenges hinder the triage of TN patients for therapy and clinical trials, and hamper the design of treatment guidelines. In response to these shortcomings, we have developed a classification of TN that aligns with the nosology of other neurologic disorders and neuropathic pain. We propose 3 diagnostic categories. Classical TN requires demonstration of morphologic changes in the trigeminal nerve root from vascular compression. Secondary TN is due to an identifiable underlying neurologic disease. TN of unknown etiology is labeled idiopathic. Diagnostic certainty is graded possible when pain paroxysms occur in the distribution of the trigeminal nerve branches. Triggered paroxysms permit the designation of clinically established TN and probable neuropathic pain. Imaging and neurophysiologic tests that establish the etiology of classical or secondary TN determine definite neuropathic pain
Sediment disturbance by Ediacaran bulldozers and the roots of the Cambrian explosion
Se han documentado fósiles de rastros de excavadoras de sedimentos en los estratos ediacaranos terminales del Grupo Nama en Namibia, donde se encuentran en el miembro Spitskop de la Formación Urusis (subgrupo Schwarzrand). Consisten en fósiles de trazas unilobadas a bilobadas horizontales a subhorizontales que describen garabatos, círculos y, más raramente, espirales y meandros abiertos, y que muestran una estructura interna indicativa de relleno activo. Su presencia sugiere que la explotación del ecoespacio infaunal poco profundo por parte de bilateros relativamente grandes ya estaba en marcha en los albores del Fanerozoico. El excavado eficiente sugiere que el desarrollo de la espina dorsal está muy probablemente relacionado con el aumento del tamaño del cuerpo de los metazoos. Estos fósiles en trazas son los primeros representantes claros hasta ahora registrados del arrastre de sedimentos, actividad que puede haber tenido un impacto negativo en las comunidades de alimentación en suspensión y/o de osmotrofos, así como en las esteras, lo que representa los primeros ejemplos de ingeniería de ecosistemas y amensalismo de grupos tróficos. La aparición de bulldozers de sedimentos puede haber promovido el establecimiento de gradientes en la distribución horizontal y vertical de material orgánico en relación con entornos espacialmente heterogéneos en el fondo marino en un momento crítico de la evolución de la Tierra.Trace fossils of sediment bulldozers are documented from terminal Ediacaran strata of the Nama Group in Namibia, where they occur in the Spitskop Member of the Urusis Formation (Schwarzrand Subgroup). They consist of unilobate to bilobate horizontal to subhorizontal trace fossils describing scribbles, circles and, more rarely, open spirals and meanders, and displaying an internal structure indicative of active fill. Their presence suggests that exploitation of the shallow infaunal ecospace by relatively large bilaterians was already well underway at the dawn of the Phanerozoic. Efficient burrowing suggests coelom development most likely linked to metazoan body-size increase. These trace fossils are the earliest clear representatives so far recorded of sediment bulldozing, an activity that may have had a negative impact on suspension-feeding and/or osmotroph communities, as well as on matgrounds, representing early examples of ecosystem engineering and trophic-group amensalism. The occurrence of sediment bulldozers may have promoted the establishment of gradients in horizontal and vertical distribution of organic material in connection with spatially heterogeneous environments on the sea floor at a critical time in Earth evolution.• Natural Sciences and Engineering Research Council (NSERC) Discovery. Grants 311726-05/13 y 311727-05/15, para Louis Alberto Buatois y Maria Gabriela Mángano
• Palaeontological Scientific Trust (Sudáfrica). Ayuda a John Almond
• Ministerio de Ciencia e Innovación y Fondo Europeo de Desarrollo Regional (FEDER). Subvención CGL-2012-37237, para Sören JensenpeerReviewe
Determining the Respiratory State From a Seismocardiographic Signal - A Machine Learning Approach
Seismocardiography (SCG) is a non-invasive method for measurement of vibrations on the chest wall originating from the heart. Respiration changes the morphology of the SCG-signal and analyzing these changes could improve the diagnostic value of SCG. This study aimed to determine the nasal respiration signal amplitude at mitral closure (MC) and aortic opening (AO) using SCG features. The three proposed methods for this were multiple regression analysis (MRA), support vector regression (SVR), and a neural network (NN). SCG, Electrocardiography and nasal-catheter flow signals were acquired from 18 healthy subjects (age 29± 6). SCG-signal fiducial points were used as features and were found using an automatic algorithm followed by manual verification. Fiducial points amplitudes, timings between these and frequency components formed 12 features. All models were trained on 80% of the data, underwent 10-fold cross-validation and were tested on the remaining 20% of the data. Predictions on test data for MC and AO time points, the Pearson correlations coefficient, and sum of squared errors of prediction were: (rMC, rAO, SSEMC, SSEAO) for the following models: NN (0.908, 0.904, 11.71, 12.05), SVR (0.881, 0.833, 18.95, 19.76) and MRA (0.450, 0.437, 51.21, 51.48). These predictive models show a strong correlation between the SCG-signal and respiration
Determining the Respiratory State From a Seismocardiographic Signal:A Machine Learning Approach
Draft Genome Sequence of Acinetobacter johnsonii C6, an Environmental Isolate Engaging in Interspecific Metabolic Interactions
ABSTRACT
Acinetobacter johnsonii
C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with
Pseudomonas putida
in biofilms. The draft genome of
A. johnsonii
C6 is 3.7 Mbp and was shaped by mobile genetic elements. It reveals genes facilitating the biodegradation of aromatic hydrocarbons and resistance to antimicrobials and metals.
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Evidence for directed percolation universality at the onset of spatiotemporal intermittency in coupled circle maps
We consider a lattice of coupled circle maps, a model arising naturally in
descriptions of solid state phenomena such as Josephson junction arrays. We
find that the onset of spatiotemporal intermittency (STI) in this system is
analogous to directed percolation (DP), with the transition being to an unique
absorbing state for low nonlinearities, and to weakly chaotic absorbing states
for high nonlinearities. We find that the complete set of static exponents and
spreading exponents at all critical points match those of DP very convincingly.
Further, hyperscaling relations are fulfilled, leading to independent controls
and consistency checks of the values of all the critical exponents. These
results lend strong support to the conjecture that the onset of STI in
deterministic models belongs to the DP universality class.Comment: Submitted to Physical Review
Draft Genome Sequence of the Yeast Pachysolen tannophilus CBS 4044/NRRL Y-2460
A draft genome sequence of the yeast Pachysolen tannophilus CBS 4044/NRRL Y-2460 is presented. The organism has the potential to be developed as a cell factory for biorefineries due to its ability to utilize waste feedstocks. The sequenced genome size was 12,238,196 bp, consisting of 34 scaffolds. A total of 4,463 genes from 5,346 predicted open reading frames were annotated with function
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