497 research outputs found
Adaptive Datenverwaltung im Internet
Aus der EinfĂĽhrung:
"Mit der ständig wachsenden Bedeutung des Internets als Medium für Kommunikation und Datenverarbeitung werden auch Qualitätsmerkmale wie Verfügbarkeit, Zuver-lässigkeit und Sicherheit immer wichtiger. Das gilt insbesondere für die Anwendung im Rahmen des e-Business und anderer kommerzieller Anwendungen [13].
Strukturbildung in P2P-Network-Communities
Peer-to-Peer-Netzwerke (P2P) und -Communities sind in der Vergangenheit nicht nur durch die Popularität von File-Sharing Systemen wie Gnutella [4] oder Freenet [1] zum Gegenstand umfangreicherer Forschungen geworden. In einem P2P-System ist jeder Computer zugleich Anbieter und Konsument von Informationen aller Art. Es existiert kein zentraler Server mehr, der Nutzinformationen oder Informationen über die Netzwerkstruktur bereithält. Es können jederzeit Teilnehmer hinzukommen oder entfernt werden, ohne daß die Funktionalität des Gesamtsystems beeinträchtigt wird. In solchen Netzwerken finden sich Nutzer zusammen, die gleiche Interessen, wie z.B. den Austausch bestimmter Daten, haben (Communities). Trotz oder gerade wegen dieser dynamischen, dezentralen Architektur haben solche System einige signifikante Vorteile gegenüber den erkömmlichen Client-Server-Lösungen [5]. Eine zentrale Instanz ist z.B. eine Schwachstelle, wenn es um Sicherheit und Zuverlässigkeit geht. Nicht nur mögliche technische Probleme können mit dem Server alle von diesem angebotenen Dienste unerreichbar machen, sondern auch böswillige Angriffe von außen. Zentrale Datenbestände sind zudem meistens auch sehr umfangreich und somit nur mit großen Aufwand zu pflegen
Cytokine and immune cell profiling in the cerebrospinal fluid of patients with neuro-inflammatory diseases
Background Cytokines play multiple roles during neuro-inflammatory processes and several cytokines have been studied in the context of specific diseases. This study provides a comprehensive picture of cerebrospinal fluid (CSF) changes during neuro-inflammation by analyzing multiple cytokines in combination with immune cell subsets and standard CSF parameters. Methods Using multiplex assays, we simultaneously measured 36 cytokines (CCL1-3, CCL7, CCL8, CCL11, CCL13, CCL19, CCL20, CCL22-27, CXCL1, CXCL2, CXCL5, CXCL6, CXCL8, CXCL9, CXCL11-13, CXCL16, CX3CL1, IL2, IL4, IL6, IL10, IL16, GM-CSF, IFN gamma, MIF, TNF alpha, and MIB1 beta) in the CSF and serum of 75 subjects. Diagnoses included clinically isolated syndrome and relapsing-remitting multiple sclerosis (MS, n = 18), secondary progressive MS (n = 8), neuro-syphilis (n = 6), Lyme neuro-borreliosis (n = 13), bacterial and viral meningitis (n = 20), and patients with non-inflammatory neurological diseases (NIND, n = 10). Cytokine concentrations were correlated with CSF standard parameters and CSF immune cell subsets (CD4 and CD8 T cells, B cells, plasmablasts, monocytes, and NK cells) quantified by flow cytometry. Results We observed increased levels of multiple cytokines (26/36) in patients with neuro-inflammatory diseases when compared to NIND that consistently correlated with CSF cell count and Q(Albumin). Most CSF cytokine concentrations correlated with each other, but correlations between CSF and serum values were scarce (3/36). Within the CSF compartment, CXCL13 showed a strong association with B cells when analyzing all patients, as well as patients with an intact blood-brain barrier (BBB). NK cells positively correlated with CSF concentrations of multiple cytokines (22/36) when analyzing all patients. These correlations were maintained when looking at patients with a disrupted BBB but not detectable in patients with an intact BBB. Conclusions Under conditions of neuro-inflammation, multiple CSF cytokines are regulated in parallel and most likely produced locally. A combined increase of CSF CXCL13 levels and B cells occurs under conditions of an intact BBB. Under conditions of a disrupted BBB, CSF NK cells show significantly increased values and seem to have a major contribution to overall inflammatory processes, reflected by a strong correlation with multiple cytokines. Future studies are necessary to address the exact kinetics of these cytokines during neuro-inflammation and their relation to specific diseases phenotypes
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Neural Process Reconstruction from Sparse User Scribbles
We present a novel semi-automatic method for segmenting neural processes in large, highly anisotropic EM (electron microscopy) image stacks. Our method takes advantage of sparse scribble annotations provided by the user to guide a 3D variational segmentation model, thereby allowing our method to globally optimally enforce 3D geometric constraints on the segmentation. Moreover, we leverage a novel algorithm for propagating segmentation constraints through the image stack via optimal volumetric pathways, thereby allowing our method to compute highly accurate 3D segmentations from very sparse user input. We evaluate our method by reconstructing 16 neural processes in a 1024Ă—1024Ă—50 nanometer-scale EM image stack of a mouse hippocampus. We demonstrate that, on average, our method is 68% more accurate than previous state-of-the-art semi-automatic methods.Engineering and Applied Science
PPARgamma activation attenuates T-lymphocyte-dependent inflammation of adipose tissue and development of insulin resistance in obese mice
<p>Abstract</p> <p>Background</p> <p>Inflammation of adipose tissue (AT) has been recently accepted as a first step towards obesity-mediated insulin resistance. We could previously show that mice fed with high fat diet (HFD) develop systemic insulin resistance (IR) and glucose intolerance (GI) associated with CD4-positive T-lymphocyte infiltration into visceral AT. These T-lymphocytes, when enriched in AT, participate in the development of fat tissue inflammation and subsequent recruitment of proinflammatory macrophages. The aim of this work was to elucidate the action of the insulin sensitizing PPARgamma on T-lymphocyte infiltration during development of IR, and comparison of the PPARgamma-mediated anti-inflammatory effects of rosiglitazone and telmisartan in diet-induced obesity model (DIO-model) in mice.</p> <p>Methods</p> <p>In order to investigate the molecular mechanisms underlying early development of systemic insulin resistance and glucose intolerance male C57BL/6J mice were fed with high fat diet (HFD) for 10-weeks in parallel to the pharmacological intervention with rosiglitazone, telmisartan, or vehicle.</p> <p>Results</p> <p>Both rosiglitazone and telmisartan were able to reduce T-lymphocyte infiltration into AT analyzed by quantitative analysis of the T-cell marker CD3gamma and the chemokine SDF1alpha. Subsequently, both PPARgamma agonists were able to attenuate macrophage infiltration into AT, measured by the reduction of MCP1 and F4/80 expression. In parallel to the reduction of AT-inflammation, ligand-activated PPARgamma improved diet-induced IR and GI.</p> <p>Conclusion</p> <p>Together the present study demonstrates a close connection between PPARgamma-mediated anti-inflammation in AT and systemic improvement of glucose metabolism identifying T-lymphocytes as one cellular mediator of PPARgamma´s action.</p
Socio-economic, political, and institutional sustainability of agroforestry in Alta Verapaz, Guatemala
Promoting sustainable agricultural practices such as agroforestry (AF) could improve long-term productivity, enhance a sustainable rural livelihood and reduce pressure on natural resources and ecosystems in the tropics. However, AF seems to have adoption problems due to external market forces, lack of skills, financial resources and know-how ending in low flexibility and discontinuity of farmers in practicing AF. The objective of this study is to identify social, institutional, and economic factors that influence the adoption of AF on the household and community level, taking the region Alta Verapaz in Guatemala as a case study. Alta Verapaz is amongst the poorest regions in the country but also a tropical biodiversity hotspot where current agricultural practices are threatening forest environments and social development objectives. Our study explores how capital accessibility and institutional incentives are related to farmer’s livelihood sustainability and AF compositions. The methodology is composed by semi-structured interviews with nineteen farmers and field observations. The interviews have been analysed based on a qualitative content analysis by using the inductive category development. Based on these outcomes, the study found that human and economical capitals are favoured in communities were institutions are present especially through AF training offers, creation of farmers cooperatives and economic incentives. The role of institutions resulted to be crucial in the promotion of organic AF methods, forest protection and creation of long-term income. The combination of agricultural diversification with institutional incentives is one key livelihood strategy adopted by the farmers in order to achieve a socio-economic and ecological sustainability of their households. The further promotion of community forestry projects, expansion of networks and ongoing agricultural trainings as well as the diversification of agricultural systems could be beneficial for farmers in Alta Verapaz
Finanzvergleich von Wirtschaftsuniversitäten in Zürich, Hamburg, Kopenhagen, Prag und Wien: Studie im Auftrag der Wirtschaftsuniversität Wien
Calculation of rescaling factors and nuclear multiplication of muons in extensive air showers
Recent results obtained from leading cosmic ray experiments indicate that
simulations using LHC-tuned hadronic interaction models underestimate the
number of muons in extensive air showers compared to experimental data. This is
the so-called muon deficit problem. Determination of the muon component in the
air shower is crucial for inferring the mass of the primary particle, which is
a key ingredient in the efforts to pinpoint the sources of ultra-high energy
cosmic rays.In this paper, we present a new method to derive the muon signal in
detectors, which uses the difference between the total reconstructed (data) and
simulated signals is roughly independent of the zenith angle, but depends on
the mass of the primary cosmic ray. Such a method offers an opportunity not
only to test/calibrate the hadronic interaction models, but also to derive the
exponent, which describes an increase of the number of muons in a
shower as a function of the energy and mass of the primary cosmic ray. Detailed
simulations show a dependence of the exponent on hadronic interaction
properties, thus the determination of this parameter is important for
understanding the muon deficit problem. We validate the method by using Monte
Carlo simulations for the EPOS-LHC and QGSJetII-04 hadronic interaction models,
and showing that this method allows us to recover the ratio of the muon signal
between EPOS-LHC and QGSJetII-04 and the average exponent for the
studied system, within less than a few percent. This is a consequence of the
good recovery of the muon signal for each primary included in the analysis.Comment: This work corresponds to the presentation at the ICNFP 2022 at
Kolymbari, Crete, in September 2022. The proceedings will be published in
Physica Scripta. arXiv admin note: text overlap with arXiv:2108.0752
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