Self-Consistent-Field Study of Adsorption and Desorption Kinetics of Polyethylene Melts on Graphite and Comparison with Atomistic Simulations

A method is formulated, based on combining self-consistent field theory with dynamically corrected transition state theory, for estimating the rates of adsorption and desorption of end-constrained chains (e.g. by crosslinks or entanglements) from a polymer melt onto a solid substrate. This approach is tested on a polyethylene/graphite system, where the whole methodology is parametrized by atomistically detailed molecular simulations. For short-chain melts, which can still be addressed by molecular dynamics simulations with reasonable computational resources, the self-consistent field approach gives predictions of the adsorption and desorption rate constants which are gratifyingly close to molecular dynamics estimates.Comment: 18 pages, 10 figure

A specification-based QoS-aware design framework for service-based applications

Effective and accurate service discovery and composition rely on complete specifications of service behaviour, containing inputs and preconditions that are required before service execution, outputs, effects and ramifications of a successful execution and explanations for unsuccessful executions. The previously defined Web Service Specification Language (WSSL) relies on the fluent calculus formalism to produce such rich specifications for atomic and composite services. In this work, we propose further extensions that focus on the specification of QoS profiles, as well as partially observable service states. Additionally, a design framework for service-based applications is implemented based on WSSL, advancing state of the art by being the first service framework to simultaneously provide several desirable capabilities, such as supporting ramifications and partial observability, as well as non-determinism in composition schemas using heuristic encodings; providing explanations for unexpected behaviour; and QoS-awareness through goal-based techniques. These capabilities are illustrated through a comparative evaluation against prominent state-of-the-art approaches based on a typical SBA design scenario

GIS as an educational tool: Mapping cultural sites in greek space-time

Το θέμα της παρούσας εργασίας είναι η χαρτογραφική παρουσίαση της πολιτιστικής διαδοχής στον ελληνικό χωρο-χρόνο που σχετίζεται με βασικές έννοιες της γεωγραφικής και ιστορικής εκπαίδευσης. Η παιδαγωγική αξία της μελέτης είναι η ανάπτυξη πέντε διακριτών δεξιότητων: της έννοιας του χρόνου-κλίμακας, της ιστορικής και γεωγραφικής κατανόησης, της χωρικής ανάλυσης και ερμηνείας, της ικανότητας διεξαγωγής γεω-ιστορικής έρευνας, και της γεω-ιστορικής διαδικασίας λήψης αποφάσεων. Η μεθοδολογία βασίζεται στη βαθμονόμηση μιας σειράς κριτηρίων για κάθε πολιτιστική περιοχή που καλύπτει τα θέματα της οικονομίας, της γεωμορφολογίας, της κοινωνίας των πολιτών, της θρησκείας, της τέχνης και της επιστήμης. Η περαιτέρω ανάλυση αυτών των δεδομένων οδηγεί στη δημιουργία μιας γεω-βάσης. Οι παλαιογεωγραφικοί και ιστορικοί χάρτες των πολιτιστικών χώρων που προέρχονται από την γεωβάση παρέχουν πληροφορίες σχετικά με τις χρονικές και χωρικές μεταβολές. Ως αποτέλεσμα, οι μαθητές θα είναι σε θέση να αναπτύξουν μια πολυδιάστατη και διεπιστημονική προσέγγιση, προκειμένου να ανακατασκευάσουν την εξέλιξη του τόπου.This paper deals with the cartographical presentation of cultural succession in Greek space-time associated with core concepts of geographic and historical education. The pedagogic value of this study is to develop five distinct skills: sense of time-scale, historical and geographic comprehension, spatial analysis and interpretation, ability to perform geo-historical research, and procedure of geohistorical decision-making. The methodology is based on the calibration of a set of criteria for each cultural site that covers the topics of economy, geomorphology, society, religion, art and science. Further analysis of these data forms a geodatabase. In addition, palaeogeographic and historical maps of the cultural sites derived by the geodatabase provide information about temporal and spatial changes. As result, students will be able to develop a multidimensional and interdisciplinary approach, in order to reconstruct the evolution of the site

Technology needs assessment of an atmospheric observation system for tropospheric research missions, part 1

The technology advancements needed to implement the atmospheric observation satellite systems for air quality research were identified. Tropospheric measurements are considered. The measurements and sensors are based on a model of knowledge objectives in atmospheric science. A set of potential missions and attendant spacecraft and sensors is postulated. The results show that the predominant technology needs will be in passive and active sensors for accurate and frequent global measurements of trace gas concentration profiles

A Genome-Wide Screen for Bacterial Envelope Biogenesis Mutants Identifies a Novel Factor Involved in Cell Wall Precursor Metabolism

The cell envelope of Gram-negative bacteria is a formidable barrier that is difficult for antimicrobial drugs to penetrate. Thus, the list of treatments effective against these organisms is small and with the rise of new resistance mechanisms is shrinking rapidly. New therapies to treat Gram-negative bacterial infections are therefore sorely needed. This goal will be greatly aided by a detailed mechanistic understanding of envelope assembly. Although excellent progress in the identification of essential envelope biogenesis systems has been made in recent years, many aspects of the process remain to be elucidated. We therefore developed a simple, quantitative, and high-throughput assay for mutants with envelope biogenesis defects and used it to screen an ordered single-gene deletion library of Escherichia coli. The screen was robust and correctly identified numerous mutants known to be involved in envelope assembly. Importantly, the screen also implicated 102 genes of unknown function as encoding factors that likely impact envelope biogenesis. As a proof of principle, one of these factors, ElyC (YcbC), was characterized further and shown to play a critical role in the metabolism of the essential lipid carrier used for the biogenesis of cell wall and other bacterial surface polysaccharides. Further analysis of the function of ElyC and other hits identified in our screen is likely to uncover a wealth of new information about the biogenesis of the Gram-negative envelope and the vulnerabilities in the system suitable for drug targeting. Moreover, the screening assay described here should be readily adaptable to other organisms to study the biogenesis of different envelope architectures

Redsharc: A Programming Model and On-Chip Network for Multi-Core Systems on a Programmable Chip

The reconfigurable data-stream hardware software architecture (Redsharc) is a programming model and network-on-a-chip solution designed to scale to meet the performance needs of multi-core Systems on a programmable chip (MCSoPC). Redsharc uses an abstract API that allows programmers to develop systems of simultaneously executing kernels, in software and/or hardware, that communicate over a seamless interface. Redsharc incorporates two on-chip networks that directly implement the API to support high-performance systems with numerous hardware kernels. This paper documents the API, describes the common infrastructure, and quantifies the performance of a complete implementation. Furthermore, the overhead, in terms of resource utilization, is reported along with the ability to integrate hard and soft processor cores with purely hardware kernels being demonstrated

Is Entrepreneurial Success Predictable? An Ex-Ante Analysis of the Character-Based Approach

This paper empirically analyzes whether the character-based approach, which focuses on the personality structure and the human capital of business founders, allows prediction of entrepreneurial success. A unique data set is used consisting of 414 persons whose personal characteristics were analyzed by different methods, namely an one-day assessment center (AC) and a standardized questionnaire, before they launched their business. Results are partly unexpected and weaker than previous ex-post findings: first, we found correlations between the AC data and the questionnaire in one subgroup only. Second, the predictive power of the AC data is slightly better than that of the questionnaire, but lower than expected in theory. Interestingly, for those subgroups where the AC data have low predictive power, the questionnaire does better. Third, when success is measured in terms of employees hired, the character-based approach is a poor predictor. Copyright 2008 The Authors.

Assessment of the use of space technology in the monitoring of oil spills and ocean pollution: Technical volume. Executive summary

The potential of space systems and technology for detecting and monitoring ocean oil spills and waste pollution was assessed as well as the impact of this application on communication and data handling systems. Agencies charged with responsibilities in this area were identified and their measurement requirements were ascertained in order to determine the spatial resolution needed to characterize operational and accidental discharges. Microwave and optical sensors and sensing techniques were evaluated as candidate system elements. Capabilities are described for the following: synthetic aperture radar, microwave scatterometer, passive microwave radiometer, microwave altimeter, electro-optical sensors currently used in airborne detection, existing space-based optical sensors, the thematic mapper, and the pointable optical linear array

Clinical Utility of Cardiovascular Magnetic Resonance Imaging for Diagnosis of Acute Myocarditis

Cardiac magnetic resonance imaging (CMR) is a novel imaging technique that may help differentiate between myocarditis and acute coronary syndrome and compares favorably to other imaging techniques because it also provides information on tissue consistency and characteristics. We herein present a case, whereby CMR was most useful in providing such a differential diagnosis