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| Registros recuperados: 2.284 | |
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| Yaroslav Strokovskyy. |
| We propose a hypothetic mechanism of ordering and shaping cells during _C. elegans_ embryogenesis. The mechanism is based on the assumption that during each round of division of cells, daughter cells acquire electric charges from its mother cells (charge conservation law is taken into account). Between the acts of division, the total electric field, generated by a system of charged cells, change relative positions of the charged cells within the region. In one’s turn, the positions of the charged cells determine the pattern of the electrostatic field. A mathematical model of such self-consistent mechanism is developed. The process of developing the sixteen-cell structure starting with one cell is simulated. The results correspond to the known... |
| Tipo: Manuscript |
Palavras-chave: Developmental Biology. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4277/version/1 |
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| Bob O'Hara; Päivi Komulainen; Outi Savolainen; Mikko J. Sillanpää. |
| A novel approach based on latent variable modelling is presented for the analysis of multivariate quantitative and qualitative trait loci. The approach is general in the sense that it enables the joint analysis of many kinds of quantitative and qualitative traits (including count data and censored traits) in a single modelling framework. In the framework, the observations are modelled as functions of latent variables, which are then affected by quantitative trait loci. Separating the analysis in this way means that measurement errors in the phenotypic observations can be included easily in the model, providing robust inferences. The performance of the method is illustrated using two real multivariate datasets, from barley and Scots pine. |
| Tipo: Manuscript |
Palavras-chave: Genetics & Genomics; Bioinformatics. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4137/version/1 |
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| Michel Thiebaut de Schotten; Flavio Dell'Acqua; Stephanie Forkel; Andrew Simmons; Francesco Vergani; Declan G.M. Murphy; Marco Catani. |
| Looking for a friend in the crowd, avoiding a sudden danger or contemplating a work of art are some examples of actions based on the efficiency of our visuo-spatial attention system. The specialization of the right brain hemisphere for visuo-spatial attention is a characteristic of most humans, but its anatomical basis remains largely unknown. Our study is the first to report in humans the existence of a bilateral parieto-frontal network whose hemispheric lateralization predicts the degree of specialization of the right hemisphere for visuo-spatial attention. Our results also suggest that this specialization is associated with an unbalanced speed of visuo-spatial processing between the two hemispheres. This lateralization may be predictive of visuo-spatial... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/5549/version/1 |
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| Pinar Wennerberg; Manuel Möller; Sonja Zillner. |
| To realize applications such as semantic medical image search different domain ontologies are necessary that provide complementary knowledge about human anatomy and radiology. Consequently, integration of these different but nevertheless related types of medical knowledge from disparate domain ontologies becomes necessary. Ontology alignment is one way to achieve this objective. Our approach for aligning medical ontologies has three aspects: (a) linguistic-based, (b) corpus-based, and (c) dialogue-based. We briefly report on the linguistic alignment (i.e. the first aspect) using an ontology on human anatomy and a terminology on radiology. |
| Tipo: Manuscript |
Palavras-chave: Bioinformatics. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3521/version/2 |
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| Pinar Wennerberg; Manuel Möller; Sonja Zillner. |
| To realize applications such as semantic medical image search different domain ontologies are necessary that provide complementary knowledge about human anatomy and radiology. Consequently, integration of these different but nevertheless related types of medical knowledge from disparate domain ontologies becomes necessary. Ontology alignment is one way to achieve this objective. Our approach for aligning medical ontologies has three aspects: (a) linguistic-based, (b) corpus-based, and (c) dialogue-based. We briefly report on the linguistic alignment (i.e. the first aspect) using an ontology on human anatomy and a terminology on radiology |
| Tipo: Manuscript |
Palavras-chave: Cancer; Bioinformatics. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3521/version/1 |
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| BaoDe Chen; WeiYi Xu; Chen Yu; ZhenYun Ni; XueFen Li; DaWei Cui. |
| Background: Obesity promotes progression to microalbuminuria and increases the risk of chronic kidney disease. Current protocols of screening microalbuminuria are not recommended for the overweight or obese.

Design and Methods: A cross-sectional study was conducted. The relationship between metabolic risk factors and microalbuminuria was investigated. A regression model based on metabolic risk factors was developed and evaluated for predicting microalbuminuria in the overweight or obese.

Results: The prevalence of MA reached up to 17.6% in Chinese overweight men. Obesity, hypertension, hyperglycemia and hyperuricemia were the important risk factors for microalbuminuria in the overweight.... |
| Tipo: Manuscript |
Palavras-chave: Molecular Cell Biology; Evolutionary Biology. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/5372/version/1 |
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| Xiaolin Zhang. |
| The neuron, when considered as a signal processing device, itsinputs are the frequency of pulses received at the synapses, and its output is the frequency of action potentials generated- in essence, a neuron is a pulse frequency signal processing device. In comparison, electrical devices use either digital or analog signals for communication or processing, and the mathematics behind these subjects is well understood. However, in regards to pulse frequency processing devices, there has not yet been a clear and persuasive mathematical model to describe the functions of neurons. It goes without saying that such a model is very important, not only for understanding neuron and neural system behavior, but also for undeveloped potential applications in industry.... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1703/version/1 |
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| Daniel R. Taub. |
| I performed a meta-analysis of studies examining the relationships among nutrient availability, plant growth rate and allocation to roots vs. shoots. Species characteristic of high fertility habits grew faster than species characteristic of less fertile habitats. While species were highly plastic in root/shoot ratio, there was a strong correlation in root/shoot across fertility levels when plants were grown across fertility gradients. This suggests that the proportional mass allocation to roots is a consistent characteristic of individual species relative to other species. There was no consistent relationship between allocation to roots and either growth rate or the fertility of habitats that species typically are found in. |
| Tipo: Manuscript |
Palavras-chave: Ecology; Plant Biology. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/185/version/1 |
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| Saheeb Ahmed Kayani. |
| In this research report, X-ray diffraction (XRD) and X-ray fluorescence (XRF) spectrometry have been used to determine the mineralogical and elemental composition of a stone sample recovered from a location near village Lehri in district Jhelum, Pakistan. The test data is compared with previous findings (as reported in literature and included in references) to identify this sample stone as part of a prehistoric meteorite ablation debris.
Further to this, carbon content of a specimen of the meteorite debris has been determined through combustion analysis. This carbon abundance has been compared with carbon wt% value of a certain type of meteorites to establish the origin and nature of the parent body of this particular meteorite debris. |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/5450/version/1 |
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| Dawid Mazurek. |
| Although the colonialism surely developed independently in Graptolithoidea and Bryozoa, both groups share similar patterns of astogeny. One of the common features is the presence of morphological gradients. Many attempts at its explanation were made for more than a half of the century. This paper discusses a new model of the late astogeny in some bryozoan colonies, showing a cyclic reappearance of secondary zones of astogenetic change and astogenetic repetition that cannot be explained by the single morphogen gradient theory. |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1585/version/1 |
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| Xin Zou; Damien Coyle; KongFatt Wong-Lin; Liam Maguire. |
| Many dementia cases, such as Alzheimer’s disease (AD), are characterized by an increase in low frequency field potential oscillations. However, a definitive understanding of the effects of the beta-Amyloid peptide, which is a main marker of AD, on the low frequency theta rhythm (4-7Hz) is still unavailable. In this work, we investigate the neural mechanisms associated with beta-Amyloid toxicity using a conductance-based neuronal network model of the hippocampus CA1 region. We simulate the effects of beta-Amyloid on the A-type fast inactivating K+ channel by modulating the maximum conductance of the current in pyramidal cells, denoted by gA. Our simulation results demonstrate that as gA decreases (through A[beta]
blockage), the... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6004/version/1 |
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| Jin Gu. |
| Transcription is the central process of gene regulation. In higher eukaryotes, the transcription of a gene is usually regulated by multiple cis-regulatory regions (CRRs). In different tissues, different transcription factors bind to their cis-regulatory motifs in these CRRs to drive tissue-specific expression patterns of their target genes. By combining the genome-wide gene expression data with the genomic sequence data, we proposed multiple-instance scoring (MIS) method to predict the tissue-specific motifs and the corresponding CRRs. The method is mainly based on the assumption that only a subset of CRRs of the expressed gene should function in the studied tissue. By testing on the simulated datasets and the fly muscle dataset, MIS can identify true... |
| Tipo: Manuscript |
Palavras-chave: Genetics & Genomics; Molecular Cell Biology; Bioinformatics. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/4038/version/1 |
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| Federico Esposti; Jacopo Lamanna; Maria Gabriella Signorini. |
| A lot of methods were created in last decade for the spatio-temporal analysis of multi-electrode array (MEA) neuronal data sets. All these methods were implemented starting from a channel to channel analysis, with a great computational effort and onerous spatial pattern recognition task. 
Our idea is to approach the MEA data collection from a different point of view, i.e. considering all channels simultaneously. We transform the 2D plus time MEA signal in a mono-dimensional plus time signal and elaborate it as a normal 1D signal, using the Space-Amplitude Transform method. 
This geometrical transformation is completely invertible and allows to employ very fast processing algorithms. 
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| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/1306/version/1 |
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| Zheng Sixiang; Liu Feihu; Zhang Chaojun; Chen Zhilin; Ma Yuhua; Meng Pinghong; Zhao Yan. |
| Mitosis is nuclear division plus cytokinesis,and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase. However, a new nucleus behavior in interspecific hybrid progenies of Lilium was observed in our experiment. Very unusual behaviors of nuclei surprisingly presented during the mitosis, such as sprouting or germination, tube-like elongation, penetrating cell membrane into a neighbor cell, the top of nuclei tube expanding, intruding and splitting of the tube-like nucleus, and micronucleus formation, and so on. Furthermore, the tetrad of meiosis was founded in mitosis of root.

Routine of the unusual nucleus behaviors observed in our experiment may be summarized as nucleus... |
| Tipo: Manuscript |
Palavras-chave: Plant Biology. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4631/version/1 |
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| UnCheol Lee; Seunghwan Kim; Gyu-Jeong Noh; Byung-Moon Choi. |
| As pointed out by William James, "the consciousness is a dynamic process, not a thing" , during which short term integration is succeeded by another differentiated neural state through the continual interplay between the environment, the body, and the brain itself. Thus, the dynamic structure underlying successive states of the brain is important for understanding human consciousness as a process. In order to investigate the dynamic property of human consciousness, we developed a new method to reconstruct a state space from electroencephalogram(EEG), in which a trajectory, reflecting states of consciousness, is constructed based on the global information integration of the brain. EEGs were obtained from 14 subjects received an intravenous... |
| Tipo: Manuscript |
Palavras-chave: Neuroscience. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/1244/version/1 |
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| Wei Sheng Zeng; Shou Zheng Tang. |
| To implement monitoring and assessment of national forest biomass, it is becoming the trend to develop generalized single-tree biomass models suitable for large scale forest biomass estimation. Considering that the theoretical biomass allometric model developed by West et al. [1,2] was statistically different from the empirical one, the two parameters in the most commonly used biomass equation M=aDb were analyzed in this paper. Firstly, based on the knowledge of geometry, the theoretical value of parameter b was deduced, i.e., b=7/3(~2.33), and the comparison with many empirical studies conducted throughout the globe indicated that the theoretical parameter could describe soundly the average allometric relationship between aboveground biomass M and D... |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6704/version/2 |
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| Wei Sheng Zeng; Shou Zheng Tang. |
| To implement monitoring and assessment of national forest biomass, it is becoming the trend to develop generalized single-tree biomass models suitable for large scale forest biomass estimation. Considering that the theoretical biomass allometric model developed by West et al. [1,2] was statistically different from the empirical one, the two parameters in the most commonly used biomass equation M=aDb were analyzed in this paper. Firstly, based on the knowledge of geometry, the theoretical value of parameter b was deduced, i.e., b=7/3(≈2.33), and the comparison with many empirical studies conducted throughout the globe indicated that the theoretical parameter could describe soundly the average allometric relationship between aboveground biomass M... |
| Tipo: Manuscript |
Palavras-chave: Ecology. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6704/version/1 |
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| Zhao Liang; Wu Shixiu; Xie Congyin; Zhang Li. |
| There are numerous mathematical or statistical models have been given out for radiation cell killing mechanism. Unfortunately, none of the model could explain the mechanism perfectly. The more advanced model for it is still necessary to be researched. Following common assumption, a new theoretical model named "target cumulating" model is induced from the molecular and particle physics level. The result of theoretical calculation gives the equation of cell survival rate corresponding to delivered dose and other sensitivity parameters. In addition to fit the cell survival curve well, the new model showed advantages with comparing to previous models. Also, the new model predicts or explains some phenomenon that had been observed in... |
| Tipo: Manuscript |
Palavras-chave: Cancer. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/2880/version/1 |
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| Domenico P. R. O. F. Fuoco. |
| In order to study and develop an economic solution to environmental pollution in water, a wide variety of materials were investigated. Natural zeolites emerge from that research as the best in class of this category. Zeolites are natural materials relatively abundant and non biodegradable, economic and good to perform processes of environmental remediation. This paper contains a full description of a new method to characterize superficial properties of natural zeolites of exotic provenience (Caribbean Islets) with atomic force microscopy (AFM). AFM works with the optical microscope simplicity and the high resolution typical of a transmission electron microscope (TEM). Structural information of mesoporous material is obtained using scanning and transmission... |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2012 |
URL: http://precedings.nature.com/documents/6828/version/1 |
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| Registros recuperados: 2.284 | |
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