2,124 research outputs found

    The Micro Slit Gas Detector

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    We describe the first tests with a new proportional gas detector. Its geometry consists in slits opened in a copper metallized kapton foil with 30 micron anode strips suspended in these openings. In this way the multiplication process is similar to a standard MSGC. The fundamental difference is the absence of an insulating substrate around the anode. Also the material budget is significantly reduced, and the problems related to charging-up or polarization are removed. Ageing properties of this detector are under study.Comment: 13 pages tex file, 10 figures ep

    Customer Orientation in Family Businesses

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    The purpose of this article is to investigate customer orientation of service employees (COSE) in family businesses. This study elaborates on the perception and importance of COSE in family-owned companies. The paper also proposes new consequences of COSE in the context of family business. The research is based on a qualitative study comprised of 13 interviews conducted on senior managers in family firms. The results are analysed using NVivo 11. This investigation confirms the relevance of the COSE construct in family businesses and the role of family influence over it. New consequences are elicited, including differentiation, customer experience, and customer well-being. The results show that practitioners consider COSE as a key element for success. This study sheds light on how COSE can be applied in a family business in order to enhance customer experience. This study expands on the potential of COSE with the use of family businesses for the first time and introduces new consequences from the original model

    NCBO Ontology Recommender 2.0: An Enhanced Approach for Biomedical Ontology Recommendation

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    Biomedical researchers use ontologies to annotate their data with ontology terms, enabling better data integration and interoperability. However, the number, variety and complexity of current biomedical ontologies make it cumbersome for researchers to determine which ones to reuse for their specific needs. To overcome this problem, in 2010 the National Center for Biomedical Ontology (NCBO) released the Ontology Recommender, which is a service that receives a biomedical text corpus or a list of keywords and suggests ontologies appropriate for referencing the indicated terms. We developed a new version of the NCBO Ontology Recommender. Called Ontology Recommender 2.0, it uses a new recommendation approach that evaluates the relevance of an ontology to biomedical text data according to four criteria: (1) the extent to which the ontology covers the input data; (2) the acceptance of the ontology in the biomedical community; (3) the level of detail of the ontology classes that cover the input data; and (4) the specialization of the ontology to the domain of the input data. Our evaluation shows that the enhanced recommender provides higher quality suggestions than the original approach, providing better coverage of the input data, more detailed information about their concepts, increased specialization for the domain of the input data, and greater acceptance and use in the community. In addition, it provides users with more explanatory information, along with suggestions of not only individual ontologies but also groups of ontologies. It also can be customized to fit the needs of different scenarios. Ontology Recommender 2.0 combines the strengths of its predecessor with a range of adjustments and new features that improve its reliability and usefulness. Ontology Recommender 2.0 recommends over 500 biomedical ontologies from the NCBO BioPortal platform, where it is openly available.Comment: 29 pages, 8 figures, 11 table

    Classification of tolerable/intolerable mucosal toxicity of head-and-neck radiotherapy schedules with a biomathematical model of cell dynamics

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    Purpose: The purpose of this study is to present a biomathematical model based on the dynamics of cell populations to predict the tolerability/intolerability of mucosal toxicity in head-and-neck radiotherapy. Methods and Materials: Our model is based on the dynamics of proliferative and functional cell populations in irradiated mucosa, and incorporates the three As: Accelerated proliferation, loss of Asymmetric proliferation, and Abortive divisions. The model consists of a set of delay differential equations, and tolerability is based on the depletion of functional cells during treatment. We calculate the sensitivity (sen) and specificity (spe) of the model in a dataset of 108 radiotherapy schedules, and compare the results with those obtained with three phenomenological classification models, two based on a biologically effective dose (BED) function describing the tolerability boundary (Fowler and Fenwick) and one based on an equivalent dose in 2 Gy fractions (EQD2) boundary (Strigari). We also perform a machine learning-like cross-validation of all the models, splitting the database in two, one for training and one for validation. Results: When fitting our model to the whole dataset, we obtain predictive values (sen + spe) up to 1.824. The predictive value of our model is very similar to that of the phenomenological models of Fowler (1.785), Fenwick (1.806), and Strigari (1.774). When performing a k = 2 cross-validation, the specificity and sensitivity in the validation dataset decrease for all models, from ˜1.82 to ˜1.55–1.63. For Fowler, the worsening is higher, down to 1.49. Conclusions: Our model has proved useful to predict the tolerability/intolerability of a dataset of 108 schedules. As the model is more mechanistic than other available models, it could prove helpful when designing unconventional dose fractionations, schedules not covered by datasets to which phenomenological models of toxicity have been fitted

    Appraisal of the inherent socio-demographic dynamics of HIV/AIDS epidemic in four districts of South-Western Uganda

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    Although HIV prevalence in Uganda is much lower than it once was, AIDS is still claiming many lives each year with clear signs of escalating rural epidemics. The objective of this study was to appraise the socio-economic and demographic dynamics of HIV/AIDS epidemic in South-Western Uganda. Data were collected with standard closed ended semi-structured questionnaires self-administered to consenting, 605 HIV/AIDS patients, selected using the multistage random sampling technique, logistic linear regression, randomized block design and Pearson’s Chi square test (á=0.01) were used to analyse the data obtained. The duration of carriage was inversely proportional (r=-0.94) to population of HIV/AIDS patients surveyed. There were 98.2% Bantu (55.5% Banyankole and 22.6% Baganda); 77.5% females and 22.5% males; more widows (38.0%) than married (35.5%). HIV/AIDS prevalence generally decreased with increasinglevel of education. The highest (66.7%) HIV/AIDS prevalence was recorded in Bushenyi, followed by 58.4% in Masaka, 57.9% in Mbarara and 53.3% in Rukungiri. Rukungiri patients above 60 years of age harboured 57.1% HIV/AIDS followed by 45.5% among Masaka patients aged 11 - 20 years and 40% among Mbarara patients less than 10 years of age. HIV/AIDS prevalence was significantly (p<0.05) dependent on socio-economic and demographic factors of surveyed population. Therefore socio-economic and demographic factors underlie HIV/AIDS prevalence in this region. Observed differences in prevalence of HIV/AIDS between the surveyed districts wereremarkable and warrant regular surveillance for updated disease  epidemiology. Education can debunk the generally misconstrued rolesof social, economic and demographic factors in the spread of HIV/AIDS

    “Western Mediterranean” (WM) broad band network: permanent seismic monitoring at the Ibero-Maghrebian region

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    The “Ibero-Maghrebian” region, a western part of the Eurasia-Africa plate boundary, is a broad deformation area without a well defined plate boundary line, comprising the Southern part of the Iberian Peninsula, the Northwestern part of Africa, the Gulf of Cadiz and the Alboran Sea, with a convergence between Iberia and Africa at some mm/year (Nuvel-1A model, DeMets et al, 1994) in a NNW-SSE direction, and a dif- ferential motion at Alboran Sea area (Buforn et al, 1995). Although seismic activity is characterized by a low to moderate magnitude and shallow depth earthquakes, big events are also well documented, among others: Lisbon earthquake (1755, I0= X), Gulf of Cadiz (1969, Ms= 8.1), or, more recently Bourmedes (2003, Mw= 7.1), some them with an associated tsunami, like Lisbon or Bourmedes earthquakes. An interme- diate seismic activity is also clearly registered from Gulf of Cadiz to mid Alboran Sea (Martin Davila and Pazos, 2003), and very deep earthquakes (h> 650 km) have been registered at Granada basin (1954, M= 7.0). In order to better study the seismic characteristics of this area, from 1996 on, ROA and the University Complutense of Madrid (UCM), with the collaboration of Geo- forschungZentrum of Potsdam (GFZ), have deployed a broad band seismic net with stations located at Southern Spain and Spanish possessions located Northern Africa, mainly surrounding the Alboran Sea, complementing the previously installed ROA SP and LP stations. This net has been named as “Western Mediterranean net” (WM FDSN code). As net was evolving, new Institutes and stations joined WM net, such a way at present is formed by ten stations located at: San Fernando (SFS), Málaga (MALA), Cartagena (CART), and Evora (UEVO, University of Evora, Portugal) at Iberian peninsula, Mahón (MAHO) at Minorca island, three stations at Melilla (MELI), Peñón de Vélez-Gomera (PVLZ), and Ceuta (CEU) at Spanish villages located Northern Africa in South Alboran Sea area, and Averroes (AVE) and Ifrane (IFR) installed at Morocco mainland as a joined effort among ISRABAT (Institut Scientifique, Univer- sité Mohammed V), ROA and UCM. Most stations are collocated with permanent geodetic GPS stations (Gárate et al, 2004). Next future plans include the installation of five stations by U. Evora at Southern Portugal area, a new station at Morocco by ISRABAT, ROA and UCM and also a new station at Oran (Algeria), as a collaboration among Université d’Oran (Algeria), ROA and UCM. All them will be associated to WM net. All WM network stations include Streckeisen STS-2 sensor, a Quanterra or Earth Data digitizer, and a SeiscomP process system (Heinloo, 2004), and all them are available in real time via phone modem or Internet, except PVLZ and CEU, which will be in short. In this work, partly funded by the Spanish Ministry of Education and Science (MEC) through the project REN2006-10311-C03-01/02 (RISTE), we will present the present status, the next future plans and some related activities of WM net

    Classification of coffee beans by GC-C-IRMS, GC-MS, and 1H-NMR

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    In a previous work using 1H-NMR we reported encouraging steps towards the construction of a robust expert system for the discrimination of coffees from Colombia versus nearby countries (Brazil and Peru), to assist the recent protected geographical indication granted to Colombian coffee in 2007.This system relies on fingerprints acquired on a 400MHz magnet and is thus well suited for small scale random screening of samples obtained at resellers or coffee shops. However, this approach cannot easily be implemented at harbour's installations, due to the elevated operational costs of cryogenic magnets. This limitation implies shipping the samples to the NMR laboratory, making the overall approach slower and thereby more expensive and less attractive for large scale screening at harbours. In this work, we report on our attempt to obtain comparable classification results using alternative techniques that have been reported promising as an alternative toNMR: GC-MS andGC-C-IRMS.Although statistically significant information could be obtained by all threemethods, the results showthat the quality of the classifiers dependsmainly on the number of variables included in the analysis; hence NMR provides an advantage since more molecules are detected to obtain a model with better predictions

    Developing Critical Collaboration Skills in Engineering Students: Results From an Empirical Study

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    In highly technical organizations, work is becoming increasingly distributed; requiring practicing engineers to master virtual collaboration skills while acquiring expertise in a range of collaboration technologies. Although there has been great emphasis on developing collaboration competencies in the engineering curriculum, empirical evidence of successful strategies for distributed team settings is scarce. As an attempt to fill this gap this study investigates the impact of a scalable intervention in developing virtual collaboration skills. The intervention, based on instructional scaffolds embedded with collaboration technologies, is aimed at supporting specific processes including planning, goal setting, clarifying goals and expectations, communication, coordination and progress monitoring. A quasi-experimental design was used to evaluate the impact of the intervention on student teamwork skills. Data from 278 graduate and undergraduate engineering students participating in virtual team projects was used in the analysis. Results from the analysis are presented suggesting a statistically significant impact of the intervention on self-management skills when comparing randomly assigned teams with and without the intervention. The intervention is designed to be scalable so that it can be embedded into existing project-based courses. Our findings have important implications for the development of teamwork skills in engineering courses and provide evidence of a successful strategy that can be integrated into the existing engineering curriculum

    Solving Large Scale Instances of the Distribution Design Problem Using Data Mining

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    In this paper we approach the solution of large instances of the distribution design problem. The traditional approaches do not consider that the instance size can significantly reduce the efficiency of the solution process. We propose a new approach that includes compression methods to transform the original instance into a new one using data mining techniques. The goal of the transformation is to condense the operation access pattern of the original instance to reduce the amount of resources needed to solve the original instance, without significantly reducing the quality of its solution. In order to validate the approach, we tested it proposing two instance compression methods on a new model of the replicated version of the distribution design problem that incorporates generalized database objects. The experimental results show that our approach permits to reduce the computational resources needed for solving large instances by at least 65%, without significantly reducing the quality of its solution. Given the encouraging results, at the moment we are working on the design and implementation of efficient instance compression methods using other data mining techniques
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