1,083 research outputs found

    Analysis of irregular behaviour on an optical computing logic cell

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    A new methodology to study irregular behaviours in logic cells is reported. It is based on two types of diagrams, namely phase and working diagrams. Sets of four bits are grouped and represented by their hexadecimal equivalent. Some hexadecimal numbers correspond to certain logic functions. The influence of the internal and external tolerances, namely those appearing in the employed devices and in the working signals, may be analysed with this method. Its importance in the case of logic structures with chaotic behaviours is studied

    Ratchet universality in the bidirectional escape from a symmetric potential well

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    The present work discusses symmetry-breaking-induced bidirectional escape from a symmetric metastable potential well by the application of zero-average periodic forces in the presence of dissipation. We characterized the interplay between heteroclinic instabilities leading to chaotic escape and breaking of a generalized parity symmetry leading to directed ratchet escape to an attractor either at infinity or at -infinity. Optimal enhancement of directed ratchet escape is found to occur when the wave form of the zero-average periodic force acting on the damped driven oscillator matches as closely as possible to a universal wave form, as predicted by the theory of ratchet universality. Specifically, the optimal approximation to the universal force triggers the almost complete destruction of the nonescaping basin for driving amplitudes which are systematically lower than those corresponding to a symmetric periodic force having the same period. We expect that this work could be potentially useful in the control of elementary dynamic processes characterized by multidirectional escape from a potential well, such as forced chaotic scattering and laser-induced dissociation of molecular systems, among others

    Torsion cycles as non-local magnetic sources in non-orientable spaces

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    Non-orientable spaces can appear to carry net magnetic charge, even in the absence of magnetic sources. It is shown that this effect can be understood as a physical manifestation of the existence of torsion cycles of codimension one in the homology of space.Comment: 17 pages, 4 figure

    Local flap reconstruction of large scalp defects

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    Scalp defects can have a number of origins, and their repair is dependent upon their location, size and depth. In the case of the scalp, the repair of even small defects is complicated. Local flaps are the reference for the reconstruction of such defects. Knowledge of scalp anatomy is essential for preparing these flaps, which must be based on one or two vascular pedicles to afford a large rotation angle ? thereby facilitating closure of the defect. The parietal zone is the location offering the greatest flap mobilization possibilities. We present a case involving the repair of a major pericranial frontoparietal scalp defect. A local transverse posterior transpositioning scalp flap was raised with the posterior auricular and occipital arteries as vascular pedicle. Following repositioning of the flap, a free partial-thickness skin graft from the thigh was used to cover the donor zone. A review is provided of the different techniques for the reconstruction of large scalp defects

    Diffusion Tensor Imaging in Alzheimer's disease

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    Attentional control and Information processing speed are central concepts in cognitive psychology and neuropsychology. Functional neuroimaging and neuropsychological assessment have depicted theoretical models considering attention as a complex and non-unitary process. One of its component processes, Attentional set-shifting ability, is commonly assessed using the Trail Making Test (TMT). Performance in the TMT decreases with increasing age in adults, Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD). Besides, speed of information processing (SIP) seems to modulate attentional performance. While neural correlates of attentional control have been widely studied, there are few evidences about the neural substrates of SIP in these groups of patients. Different authors have suggested that it could be a property of cerebral white matter, thus, deterioration of the white matter tracts that connect brain regions related to set-shifting may underlie the age-related, MCI and AD decrease in performance. The aim of this study was to study the anatomical dissociation of attentional and speed mechanisms. Diffusion tensor imaging (DTI) provides a unique insight into the cellular integrity of the brain, offering an in vivo view into the microarchitecture of cerebral white matter. At the same time, the study of ageing, characterized by white matter decline, provides the opportunity to study the anatomical substrates speeded or slowed information processing. We hypothesized that FA values would be inversely correlated with time to completion on Parts A and B of the TMT, but not the derived scores B/A and B-A

    Long-term impact of sustainable land management practices on soil bacterial community in an almond orchard in south Spain

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    [SPA] Una estructura de comunidad bacteriana saludable es uno de los principales indicadores de calidad del suelo. Las prácticas agrícolas modernas en las que se aplican labranza intensa y fertilizantes químicos continúan poniendo en juego el equilibrio ambiental y la sostenibilidad de la producción día a día. En este estudio, nuestro objetivo fue evaluar el efecto a largo plazo de prácticas sostenibles de bajos insumos, como la labranza reducida y el abono verde sobre la comunidad bacteriana edáfica en un cultivo de almendros del sur de España. La labranza reducida y la adición de abono verde han demostrado la estructura de la comunidad bacteriana más estable y la abundancia de especies con respecto a los métodos convencionales. El carbono orgánico del suelo y la comunidad bacteriana se mejoran con un enfoque sostenible de bajos insumos. [ENG] A healthy bacterial community structure is one of the main aspects of soil quality indicators. Modern agricultural practices, where intense tillage and chemical fertilizers are applied, continue to put environmental balance and sustainability of production at stake day by day. In this study, we aimed to assess the long-term effect of low-input sustainable practices such as reduced tillage and green manure on soil bacterial communities in an almond orchard from south Spain. Reduced tillage and addition of green manure has shown the most stable bacterial community structure and species abundance with respect to conventional practice. Soil organic carbon and bacterial community are improved by low-input sustainable approach.This work was conducted as a part of the European Commission Horizon 2020 project Diverfarming [grant agreement 728003]

    Impact of different crop rotation sequences and management practices on soil bacterial diversity in Northern Netherlands

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    [SPA] La identificación de la estructura y diversidad bacteriana edáfica proporciona una visión enorme de la calidad del suelo debido a las intensas relaciones bioquímicas entre el microbioma del suelo y las plantas que interactúan. El objetivo de este estudio fue evaluar cómo diferentes sistemas de cultivo diversificados bajo dos diferentes tipos de manejo (convencional y biodinámico) afectan a la diversidad bacteriana del suelo. La comunidad bacteriana del suelo se identificó a través de la secuenciación de próxima generación de genes de codificación del RNAr 16S bacteriano. Los resultados mostraron que diferentes secuencias de rotaciones de cultivos, el periodo de implementación de las rotaciones y la práctica de manejo tienen una fuerte influencia en la biomasa microbiana, la biodiversidad bacteriana y la abundancia de diferentes filos bacterianos. [ENG] Identification of soil bacterial community structure and diversity provides a huge insight into soil quality due to the intense biochemical relationships between soil microbiome and interacting plants. The aim of this study was to assess how different diversified cropping systems under two different management (conventional and biodynamic) can affect soil bacterial diversity. Soil bacterial community was identified through next-generation sequencing of 16S rRNA coding genes of soil bacteria. The findings showed that different sequences of crop rotations, period of implementation of rotations and management practice had a strong influence on soil microbial biomass, bacterial biodiversity and the abundance of different bacterial phyla, without a specific trend regulated by these factors.This work was supported by the European Commission Horizon 2020 project Diverfarming [grant agreement 728003]

    Implication of miR-612 and miR-1976 in the regulation of TP53 and CD40 and their relationship in the response to specific weight-loss diets

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    Background: Non-coding RNAs (i.e., miRNAs) play a role in the development of obesity and related comorbidities and the regulation of body weight. Objective: To identify candidate miRNA biomarkers throughout omics approaches in order to predict the response to specific weight-loss dietary treatments. Design: Genomic DNA and cDNA isolated from white blood cells of a subset from the RESMENA nutritional intervention study (Low-responders (LR) vs High-responders (HR)) was hybridized in Infinium Human Methylation450 BeadChip and in Illumina Human HT-12 v4 gene expression BeadChips arrays respectively. A bioinformatic prediction of putative target sites of selected miRNAs was performed by applying miRBase algorithms. HEK-293T cells were co-transfected with expression vectors containing the 3'-UTR of candidate genes to validate the binding of miRNAs to its target sites. Results: 134 miRNAs were differentially methylated between HR and LR in the methylation array, whereas 44 miRNAs were differentially expressed between both groups in the expression array. Specifically, miR-1237, miR-1976, miR-642, miR-636, miR-612 and miR-193B were simultaneously hypomethylated and overexpressed in HR. miR-612 and miR-1976 showed greatest differences in methylation and expression levels, respectively. The bioinformatic prediction revealed that TP53 was a putative target gene of miR-612 and CD40 of miR-1976. Moreover, TP53 was downregulated in the expression array when comparing HR vs LR expression levels adjusted by sex, diet, age and baseline weight, and CD40 showed a statistical trend. Furthermore, gene expression levels of TP53 and CD40 in white blood cells, when measured by qPCR, were also downregulated in HR. Finally, miR-612 and miR-1976 potently repressed TP53 and CD40 respectively by targeting its 3'-UTR regions. Conclusion: miR-612 and miR-1976 levels could be prospective biomarkers of response to specific weight-loss diets and might regulate the gene expression of TP53 and CD40

    Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data

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    Grapheme-color synesthesia is a neurological phenomenon in which viewing achromatic letters/numbers leads to automatic and involuntary color experiences. In this study, voxel-based morphometry analyses were performed on T1 images and fractional anisotropy measures to examine the whole brain in associator grapheme-color synesthetes. These analyses provide new evidence of variations in emotional areas (both at the cortical and subcortical levels), findings that help understand the emotional component as a relevant aspect of the synesthetic experience. Additionally, this study replicates previous findings in the left intraparietal sulcus and, for the first time, reports the existence of anatomical differences in subcortical gray nuclei of developmental grapheme-color synesthetes, providing a link between acquired and developmental synesthesia. This empirical evidence, which goes beyond modality-specific areas, could lead to a better understanding of grapheme-color synesthesia as well as of other modalities of the phenomenon
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