Search results for "resolution"

The efficiency of gel permeation chromatography

2007

The resolution power of gel permeation chromatography (GPC) columns and their combinations is tested as a function of the pore sizes of the gels and as a function of the elution velocity. The efficiency of GPC is characterized by the ratio UG/UT, where UG is the experimental, and UT the theoretical, inhomogeneity. The latter quantity is obtained from absolute measurements of Mw, and Mn. The ratio passes through a minimum for a series of columns with increasing pore sizes. The minimum occurs at that column or column set which is best suited to resolving a given polymer. UG/UT for any column decreases with decreasing elution velocity. At a certain velocity UG/UT becomes 1. This velocity is us…

Variations in Substitution Rate in Human and Mouse Genomes

2003

We present a method to quantify spatial fluctuations of the substitution rate on different length scales throughout genomes of eukaryotes. The fluctuations on large length scales are found to be predominantly a consequence of a coarse-graining effect of fluctuations on shorter length scales. This is verified for both the mouse and the human genome. We also found that both species show similar standard deviation of fluctuations even though their mean substitution rate differs by a factor of two. Our method furthermore allows to determine time-resolved substitution rate maps from which we can compute auto-correlation functions in order to quantify how fast the spatial fluctuations in substitu…

Histone Code and Higher-Order Chromatin Folding: A Hypothesis

2016

AbstractHistone modifications alone or in combination are thought to modulate chromatin structure and function; a concept termed histone code. By combining evidence from several studies, we investigated if the histone code can play a role in higher-order folding of chromatin. Firstly using genomic data, we analyzed associations between histone modifications at the nucleosome level. We could dissect the composition of individual nucleosomes into five predicted clusters of histone modifications. Secondly, by assembling the raw reads of histone modifications at various length scales, we noticed that the histone mark relationships that exist at nucleosome level tend to be maintained at the high…

Estimation of Purkinje trees from electro-anatomical mapping of the left ventricle using minimal cost geodesics

2015

The electrical activation of the heart is a complex physiological process that is essential for the understanding of several cardiac dysfunctions, such as ventricular tachycardia (VT). Nowadays, patient-specific activation times on ventricular chambers can be estimated from electro-anatomical maps, providing crucial information to clinicians for guiding cardiac radio-frequency ablation treatment. However, some relevant electrical pathways such as those of the Purkinje system are very difficult to interpret from these maps due to sparsity of data and the limited spatial resolution of the system. We present here a novel method to estimate these fast electrical pathways from the local activati…

Application of artificial neural networks and logistic regression to the prediction of forest fire danger in Galicia using MODIS data

2012

Fire danger models are a very useful tool for the prevention and extinction of forest fires. Some inputs of these models, such as vegetation status and temperature, can be obtained from remote sensing images, which offer higher spatial and temporal resolution than direct ground measures. In this paper, we focus on the Galicia region (north-west of Spain), and MODIS (Moderate Resolution Imaging Spectroradiometer) images are used to monitor vegetation status and to obtain land surface temperature as essential inputs in forest fire danger models. In this work, we tested the potential of artificial neural networks and logistic regression to estimate forest fire danger from remote sensing and f…

Sensitivity of the C-band SRTM DEM Vertical Accuracy to Terrain Characteristics and Spatial Resolution

2008

This work reports the results of a careful regional analysis of the SRTM DEM (Shuttle Radar Topography Mission – Digital Elevation Model) vertical accuracy as a function of both topography and Land-Use/Land Cover (LULC). Absolute vertical errors appear LULC-dependent, with some values greater than the stated accuracy of the SRTM dataset, mostly over forested areas. The results show that the structure of the errors is well modeled by a cosine power n of the local incidence angle (θloc). SRTM quality is further assessed using slope and topographical similarity indexes. The results show a lower relative accuracy on slope with a R2 = 0.5 and a moderate agreement (Kappa ≈ 0.4) between SRTM- and …

El rrgimen jurrdico del arbitraje comercial internacional en Bolivia (The Legal Regime of International Commercial Arbitration in Bolivia)

2014

Spanish Abstract: El presente articulo analiza en profundidad la actual situacion del tratamiento del arbitraje comercial internacional en Bolivia, sus tendencias y las dificultades que afronta. El trabajo estudia de manera critica las soluciones aportadas por la Ley 1770 de conciliacion y arbitraje, su ambito y lagunas. English Abstract: This Article studies in depth the current situation of the legal regime of International Commercial Arbitration in Bolivia and its trends and difficulties. It analyzes in a critical manner the different solutions provided by the Act 1770 on Arbitration and Conciliation, their scope and gaps.

New geo-portal for MODIS/SEVIRI image products with geolocation-based retrieval functionality

2015

A large number of remote sensing data sets have been collected in recent years by Earth observation instruments such as the moderate resolution imaging spectroradiometer (MODIS) aboard the Terra/Aqua satellite and the spinning enhanced visible and infrared imager (SEVIRI) aboard the geostationary platform Meteosat Second Generation. The advanced remote sensing products resulting from the analysis of these data are useful in a wide variety of appli- cations but require significant resources in terms of storage, retrieval, and analysis. Despite the wide availability of these MODIS/SEVIRI products, the data coming from these instruments are spread among different locations and retrieved from d…

Coherent South American Monsoon variability during the last millennium revealed through high‐resolution proxy records

2019

Quantification of the microstructural evolution of polycrystalline fabrics using FAME: Application to in situ deformation of ice

2014

Abstract In geology, glaciology and material science new technological advances result in an ever increasing amount of data and datasets, in particular when in situ experiments are conducted. Rapid, rigorous and reliable statistical treatment is needed to allow researchers to access these large datasets for further analysis. Here, we present FAME (Fabric Analyser based Microstructure Evaluation), a suite of Matlab® scripts that utilize the Matlab® open-source toolboxes MTEX and PolyLX (optional) for rapid quantification of thin section data. The data has been collected using an automated Fabric Analyser at a spatial resolution of 5 μm/pixel. From the dataset, grain maps are reconstructed an…