Statistical mechanics of lossy data compression using a non-monotonic perceptron

The performance of a lossy data compression scheme for uniformly biased Boolean messages is investigated via methods of statistical mechanics. Inspired by a formal similarity to the storage capacity problem in the research of neural networks, we utilize a perceptron of which the transfer function is appropriately designed in order to compress and decode the messages. Employing the replica method, we analytically show that our scheme can achieve the optimal performance known in the framework of lossy compression in most cases when the code length becomes infinity. The validity of the obtained results is numerically confirmed.Comment: 9 pages, 5 figures, Physical Review

Polynomial iterative algorithms for coloring and analyzing random graphs

We study the graph coloring problem over random graphs of finite average connectivity $c$. Given a number $q$ of available colors, we find that graphs with low connectivity admit almost always a proper coloring whereas graphs with high connectivity are uncolorable. Depending on $q$, we find the precise value of the critical average connectivity $c_q$. Moreover, we show that below $c_q$ there exist a clustering phase $c\in [c_d,c_q]$ in which ground states spontaneously divide into an exponential number of clusters. Furthermore, we extended our considerations to the case of single instances showing consistent results. This lead us to propose a new algorithm able to color in polynomial time random graphs in the hard but colorable region, i.e when $c\in [c_d,c_q]$.Comment: 23 pages, 10 eps figure

Repeatability and reproducibility of the Forskolin-induced swelling (FIS) assay on intestinal organoids from people with Cystic Fibrosis

Background: The forskolin-induced swelling (FIS) assay measures CFTR function on patient-derived intestinal organoids (PDIOs) and may guide treatment selection for individuals with Cystic Fibrosis (CF). The aim of this study is to demonstrate the repeatability and reproducibility of the FIS assay following a detailed Standard Operating Procedure (SOP), thus advancing the validation of the assay for precision medicine (theranostic) applications. Methods: Over a 2-year period, FIS responses to CFTR modulators were measured in four European labs. PDIOs from six subjects with CF carrying different CFTR genotypes were used to assess the repeatability and reproducibility across the dynamic range of the assay. Results: Technical, intra-assay repeatability was high (Lin's concordance correlation coefficient (CCC) 0.95–0.98). Experimental, within-subject repeatability was also high within each lab (CCCs all >0.9). Longer-term repeatability (>1 year) showed more variability (CCCs from 0.67 to 0.95). The reproducibility between labs was also high (CCC ranging from 0.92 to 0.97). Exploratory analysis also found that between-lab percentage of agreement of dichotomized CFTR modulator outcomes for predefined FIS thresholds ranged between 78 and 100 %. Conclusions: The observed repeatability and reproducibility of the FIS assay within and across different labs is high and support the use of FIS as biomarker of CFTR function in the presence or absence of CFTR modulators

Multigranular exocytosis of Weibel-Palade bodies in vascular endothelial cells

Regulated exocytosis of Weibel-Palade bodies (WPBs) is a pivotal mechanism via which vascular endothelial cells initiate repair in response to injury and inflammation. Several pathways have been proposed to enable differential release of bioactive molecules from WPBs under different pathophysiologic conditions. Due to the complexity, many aspects of WPB biogenesis and exocytosis are still poorly understood. Herein, we have investigated the regulated exocytosis of the major WPB constituent, von Willebrand Factor (VWF), which upon its release forms strings of up to several millimeters long that capture circulating platelets and thereby initiate the formation of a haemostatic plug. Using correlative, fluorescence, and electron microscopic imaging techniques, we provide evidence that multigranular exocytosis is an important pathway for VWF release in secretagogue-challenged human umbilical vein endothelial cells. A novel membrane-delimited structure (secretory pod) was identified as the site of WPB coalescence and VWF exocytosis. Clathrin-coated profiles present on the secretory pods suggested remodeling via compensatory membrane retrieval. Small, 30- to 40-nm cytoplasmic vesicles (nanovesicles) mediated the fusion of WPBs with secretory pods. Multigranular exocytosis may facilitate VWF string formation by pooling the content of multiple WPBs. In addition, it may provide a novel mechanism for the differential release of WPB cargo.Microscopic imaging and technolog

Geothermal energy and heat storage in aquifers

After the first energy crisis in 1973 various research programmes to do with energy conservation and diversification of energy resources were set up in the Netherlands. A number of these were directed to the rest of the subsoil for the following purposes: - the extraction of geothermal energy from great depths (1800-3000 m below surface); - the extraction of geothermal energy from shallow depths, using the heat pumps; - seasonal storage of heat and cold at shallow and intermediate depths ; - the storage of energy from power plants in caverns or porous bodies, e.g. compressed air in aquifers during daily periods of low consumption. These programmes were funded by the Netherlands Ministry of Economic Affairs and by the Commission of the European Community. During this technical meeting the results of investigations on geothermal energy extraction and heat storage in the subsoil will be presented. The subjects discussed will include the geohydrological boundary conditions, geological, geochemical and environmental aspects, the test facility that is being established on TNO premises in Delft and the results of a geothermal test well in Asten. Although the energy situation has changed considerably during the last years and instead of a shortage there now appears to be an energy surplus, it is most likely that the subjects discussed during this meeting remain topical. The main driving force may become the urgency to reduce carbon dioxide emission because of its environmental consequences

Hydrochemistry and energy storage in aquifers

This volume of the series Proceedings and Information of the TNO Committee on Hydrological Research (CHO-TNO) contains the contributions as presented on the 48th technical meeting of the CHO-TNO, "Hydrochemistry and energy storage in aquifers". During this symposium recent results have been presented on research which has been conducted within the framework of Annex VI of the International Energy Agency (IEA); Environmental and Chemical Aspects of Thermal Energy Storage in Aquifers and Research and Development of Water Treatment Methods. The Dutch contribution within the IEA framework is coordinated and sponsored by the Netherlands Agency for Energy and the Environment (NOVEM BV) in the Dutch research program: National Research Program on Geothermal Energy and Energy Storage in Aquifers (NOAA)

Genome composition of reassortants between MDV and <i>wt</i>l viruses identified by pyrosequencing.

<p>Genome composition of reassortants between MDV and <i>wt</i>l viruses identified by pyrosequencing.</p