1,571 research outputs found

    Fractal Behaviour in the O(3) Model

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    We study domain formation in the two-dimensional O(3) model near criticality. The fractal dimension of these domains is determined with good statistical accuracy.Comment: 6 pages + 3 figures (concatenated PS files, uuencoded gz-compressed

    Context-aware user modeling strategies for journey plan recommendation

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    Popular journey planning systems, like Google Maps or Yahoo! Maps, usually ignore user’s preferences and context. This paper shows how we applied context-aware recommendation technologies in an existing journey planning mobile application to provide personalized and context-dependent recommendations to users. We describe two different strategies for context-aware user modeling in the journey planning domain. We present an extensive performance comparison of the proposed strategies by conducting a user-centric study in addition to a traditional offline evaluation methodPeer ReviewedPostprint (published version

    A molecular interpretation of the dynamics of diffusive mass transport of water within a glassy polyetherimide

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    The diffusion process of water molecules within a polyetherimide (PEI) glassy matrix has been analyzed by combining the experimental analysis of water sorption kinetics performed by FTIR spectroscopy with theoretical information gathered from Molecular Dynamics simulations and with the expression of water chemical potential provided by a non‐equilibrium lattice fluid model able to describe the thermodynamics of glassy polymers. This approach allowed us to construct a convincing description of the diffusion mechanism of water in PEI providing molecular details of the process related to the effects of the cross‐ and self‐hydrogen bonding established in the system on the dynamics of water mass transport

    QED in strong, finite-flux magnetic fields

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    Lower bounds are placed on the fermionic determinants of Euclidean quantum electrodynamics in two and four dimensions in the presence of a smooth, finite-flux, static, unidirectional magnetic field B(r)=(0,0,B(r))B(r) =(0,0,B(r)), where B(r)≄0B(r) \geq 0 or B(r)≀0B(r) \leq 0, and rr is a point in the xy-plane.Comment: 10 pages, postscript (in uuencoded compressed tar file

    Translational selection on SHH genes

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    Codon usage bias has been observed in various organisms. In this study, the correlation between SHH genes expression in some tissues and codon usage features was analyzed by bioinformatics. We found that translational selection may act on compositional features of this set of genes

    A novel series of compositionally biased substitution matrices for comparing Plasmodium proteins

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    <p>Abstract</p> <p>Background</p> <p>The most common substitution matrices currently used (BLOSUM and PAM) are based on protein sequences with average amino acid distributions, thus they do not represent a fully accurate substitution model for proteins characterized by a biased amino acid composition. This problem has been addressed recently by adjusting existing matrices, however, to date, no empirical approach has been taken to build matrices which offer a substitution model for comparing proteins sharing an amino acid compositional bias. Here, we present a novel procedure to construct series of symmetrical substitution matrices to align proteins from similarly biased <it>Plasmodium </it>proteomes.</p> <p>Results</p> <p>We generated substitution matrices by selecting from the BLOCKS database those multiple alignments with a compositional bias similar to that of <it>P. falciparum </it>and <it>P. yoelii </it>proteins. A novel 'fuzzy' clustering method was adopted to group sequences within these alignments, showing that this method retains more complete information on the amino acid substitutions when compared to hierarchical clustering. We assessed the performance against the BLOSUM62 series and showed that the usage of our matrices results in an improvement in the performance of BLAST database searches, greatly reducing the number of false positive hits. We then demonstrated applications of the use of novel matrices to improve the annotation of homologs between the two <it>Plasmodium </it>species and to classify members of the <it>P. falciparum </it>RIFIN/STEVOR family.</p> <p>Conclusion</p> <p>We confirmed that in the case of compositionally biased proteins, standard BLOSUM matrices are not suited for optimal alignments, and specific substitution matrices are required. In addition, we showed that the usage of these matrices leads to a reduction of false positive hits, facilitating the automatic annotation process.</p

    The Single-Particle density of States, Bound States, Phase-Shift Flip, and a Resonance in the Presence of an Aharonov-Bohm Potential

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    Both the nonrelativistic scattering and the spectrum in the presence of the Aharonov-Bohm potential are analyzed. The single-particle density of states (DOS) for different self-adjoint extensions is calculated. The DOS provides a link between different physical quantities and is a natural starting point for their calculation. The consequences of an asymmetry of the S matrix for the generic self-adjoint extension are examined. I. Introduction II. Impenetrable flux tube and the density of states III. Penetrable flux tube and self-adjoint extensions IV. The S matrix and scattering cross sections V. The Krein-Friedel formula and the resonance VI. Regularization VII. The R --> 0 limit and the interpretation of self-adjoint extensions VIII. Energy calculations IX. The Hall effect in the dilute vortex limit X. Persistent current of free electrons in the plane pierced by a flux tube XI. The 2nd virial coefficient of nonrelativistic interacting anyons XII. Discussion of the results and open questionsComment: 68 pages, plain latex, 7 figures, 3 references and one figure added plus a few minor text correction

    ‘Stick them to the cross’:Anti-trafficking apps and the production of ignorance

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    There is a long history of ignorance production around trafficking in human beings. A proliferation of anti-trafficking apps plays an important role in the reinforcement of this ignorance. Anti-trafficking apps work in different ways to other (mis)information tools, but there is a lack of academic research on the topic. This paper addresses this gap through an agnotological approach: focusing on how ignorance is produced and becomes productive, rather than seeing ignorance as just a lack of knowledge. We investigate how anti-trafficking apps are used to manipulate (mis)understandings of and responses to human trafficking by enabling new types of awareness raising, user participation and ignorance production. The networking of ignorance that this allows – and the integration of this into new aspects of everyday life – illustrates de Goede’s (2012) warning that “the network is problematic as a security technique
because, ultimately, it has no outside” (p. 228)

    Factors Influencing the Implementation of Integrated Management of Childhood Illness (IMCI) by Healthcare Workers at Public Health centers & Dispensaries in Mwanza, Tanzania.

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    \ud Integrated Management of Childhood Illness (IMCI) was developed by the World Health Organization (WHO) and the United Nations International Children's Fund (UNICEF) and aims at reducing childhood morbidity and mortality in resource-limited settings including Tanzania. It was introduced in 1996 and has been scaled up in all districts in the country. The purpose of this study was to identify factors influencing the implementation of IMCI in the health facilities in Mwanza, Tanzania since reports indicates that the guidelines are not full adhered to by the healthcare workers. A cross-sectional study design was used and a sample size of 95 healthcare workers drawn from health centers and dispensaries within Mwanza city were interviewed using self-administered questionnaires. Structured interview was also used to get views from the city IMCI focal person and the 2 facilitators. Data were analyzed using SPSS and presented using figures and tables. Only 51% of healthcare workers interviewed had been trained. 69% of trained Healthcare workers expressed understanding of the IMCI approach. Most of the respondents (77%) had a positive attitude that IMCI approach was a better approach in managing common childhood illnesses especially with the reality of resource constraint in the health facilities. The main challenges identified in the implementation of IMCI are low initial training coverage among health care workers, lack of essential drugs and supplies, lack of onsite mentoring and lack of refresher courses and regular supportive supervision. Supporting the healthcare workers through training, onsite mentoring, supportive supervision and strengthening the healthcare system through increasing access to essential medicines, vaccines, strengthening supply chain management, increasing healthcare financing, improving leadership & management were the major interventions that could assist in IMCI implementation. The healthcare workers can implement better IMCI through the collaboration of supervisors, IMCI focal person, Council Health Management Teams (CHMT) and other stakeholders interested in child health. However, significant barriers impede a sustainable IMCI implementation. Recommendations have been made related to supportive supervision and HealthCare system strengthening among others.\u
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