3,799 research outputs found

    An agent-based approach to spatial epidemics through GIS

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    This study introduces a bottom up approach to model the complex phenomena involving the spread of epidemics in a human population with spatial dependence. To pursue this, several concepts and technologies are assembled together such as Artificial Life, Complex Networks, and Geographical Information Systems (GIS). At the beginning of this project, a Cellular Automata (CA) model was developed, but that was replaced later by an agent-based model (ABM) as it seemed more ad equate for this particular context the main target was relaxing the assumptions of homogeneous space and of random mixing of individuals. The model is split into a movement model and an infection model. The movement model uses network concepts and combines different ranges of movements to emulate the movement of individuals in human populations. The infection model is based on a classic SEIR ( Susceptible- Latent-Infectious-Removed) model and it is flexible enough to accommodate different infectious diseases. Both these models are probabilistic. The model was implemented from scratch in C++, and developed within a Geographical Information Systems (GIS) environment that provides functions for the display and analysis of geographic informa tion. Finally, some spatial vaccination strategies were implemented which illustrates a useful purpose of this kind of simulation model, for instance for aiding in the definition of health policies. The documented simulations cover the sensitivity analysis of the parameters of the movement and infection model, and there are also simulations to reproduce a mumps outbreak that occurred in Portugal between 1993 and 1996. In this way, an application of the epidemic model was illustrated for a case study, that enabled an analysis and interpretation of the model efficiency

    Jet Substructure Without Trees

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    We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is competitive with existing methods.Comment: 22 pages, 16 figures, version accepted by JHE

    Calreticulin is a secreted BMP antagonist, expressed in Hensen's node during neural induction

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    Hensen's node is the “organizer” of the avian and mammalian early embryo. It has many functions, including neural induction and patterning of the ectoderm and mesoderm. Some of the signals responsible for these activities are known but these do not explain the full complexity of organizer activity. Here we undertake a functional screen to discover new secreted factors expressed by the node at this time of development. Using a Signal Sequence Trap in yeast, we identify several candidates. Here we focus on Calreticulin. We show that in addition to its known functions in intracellular Calcium regulation and protein folding, Calreticulin is secreted, it can bind to BMP4 and act as a BMP antagonist in vivo and in vitro. Calreticulin is not sufficient to account for all organizer functions but may contribute to the complexity of its activity

    The mass area of jets

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    We introduce a new characteristic of jets called mass area. It is defined so as to measure the susceptibility of the jet's mass to contamination from soft background. The mass area is a close relative of the recently introduced catchment area of jets. We define it also in two variants: passive and active. As a preparatory step, we generalise the results for passive and active areas of two-particle jets to the case where the two constituent particles have arbitrary transverse momenta. As a main part of our study, we use the mass area to analyse a range of modern jet algorithms acting on simple one and two-particle systems. We find a whole variety of behaviours of passive and active mass areas depending on the algorithm, relative hardness of particles or their separation. We also study mass areas of jets from Monte Carlo simulations as well as give an example of how the concept of mass area can be used to correct jets for contamination from pileup. Our results show that the information provided by the mass area can be very useful in a range of jet-based analyses.Comment: 36 pages, 12 figures; v2: improved quality of two plots, added entry in acknowledgments, nicer form of formulae in appendix A; v3: added section with MC study and pileup correction, version accepted by JHE

    CANFOR Portuguese version: validation study

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    This study is embedded in the larger project "Needs Assessment of the Mentally Disordered Prisoners" funded by Fundacao para a Ciencia e Tecnologia (PIC/IC/83257/2007). We acknowledge the General-Director for Prison Services for his authorization, the Prisons' Directors for their support, the medical and non-medical staff who collaborated in this study and detainees for their participation. Special thanks to Dr Ana Cabral for her support inside the prisons and Dr Jorge Pereira for his assistance in manuscript preparation. In memory of our late friend Dr Jose Morais, who collaborated on and supported this study from the beginning.BACKGROUND The increase in prisoner population is a troublesome reality in several regions of the world. Along with this growth there is increasing evidence that prisoners have a higher proportion of mental illnesses and suicide than the general population. In order to implement strategies that address criminal recidivism and the health and social status of prisoners, particularly in mental disordered offenders, it is necessary to assess their care needs in a comprehensive, but individual perspective. This assessment must include potential harmful areas like comorbid personality disorder, substance misuse and offending behaviours. The Camberwell Assessment of Need - Forensic Version (CANFOR) has proved to be a reliable tool designed to accomplish such aims. The present study aimed to validate the CANFOR Portuguese version. METHODS The translation, adaptation to the Portuguese context, back-translation and revision followed the usual procedures. The sample comprised all detainees receiving psychiatric care in four forensic facilities, over a one year period. A total of 143 subjects, and respective case manager, were selected. The forensic facilities were chosen by convenience: one prison hospital psychiatric ward (n=68; 47.6%), one male (n=24; 16.8%) and one female (n=22; 15.4%) psychiatric clinic and one civil security ward (n=29; 20.3%), all located nearby Lisbon. Basic descriptive statistics and Kappa weighted coefficients were calculated for the inter-rater and the test-retest reliability studies. The convergent validity was evaluated using the Global Assessment of Functioning and the Brief Psychiatric Rating Scale scores. RESULTS The majority of the participants were male and single, with short school attendance, and accused of a crime involving violence against persons. The most frequent diagnosis was major depression (56.1%) and almost half presented positive suicide risk. The reliability study showed average Kappa weighted coefficients of 0.884 and 0.445 for inter-rater and test-retest agreement, respectively. The convergent validity study presented highly significant correlations between unmet needs scores, GAF and BPRS scores. CONCLUSIONS The CANFOR Portuguese version revealed similar psychometric properties to the original English version. Moreover, the results of the reliability and validity studies indicate that the tool is appropriate for individual care needs assessment and as a guide for the mental health and social interventions in forensic psychiatric services.publishersversionpublishe

    Identifying Boosted Objects with N-subjettiness

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    We introduce a new jet shape -- N-subjettiness -- designed to identify boosted hadronically-decaying objects like electroweak bosons and top quarks. Combined with a jet invariant mass cut, N-subjettiness is an effective discriminating variable for tagging boosted objects and rejecting the background of QCD jets with large invariant mass. In efficiency studies of boosted W bosons and top quarks, we find tagging efficiencies of 30% are achievable with fake rates of 1%. We also consider the discovery potential for new heavy resonances that decay to pairs of boosted objects, and find significant improvements are possible using N-subjettiness. In this way, N-subjettiness combines the advantages of jet shapes with the discriminating power seen in previous jet substructure algorithms.Comment: 26 pages, 26 figures, 2 tables; v2: references added; v3: discussion of results extende

    Unraveling Depressive Symptomatology and Risk Factors in a Changing World

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    Funding Information: The present publication was funded by the Fundação Ciência e Tecnologia, IP national support, through CHRC (UIDP/04923/2020). Publisher Copyright: © 2023 by the authors.Background: This study aimed to examine the prevalence and factors associated with symptoms of depression during the third wave of the COVID-19 pandemic. Methods: A representative sample of Portuguese adults was included in this populational survey, conducted between 25 March and 31 July 2021, with participants completing a structured questionnaire via phone interview. The symptoms of depression were measured using the Portuguese version of the Hospital Anxiety and Depression Scale (HADS). Multivariate logistic regression analyses were used to examine the association between sociodemographic, health, and lifestyle factors and depression levels (normal, mild, or moderate/severe). Results: The estimated prevalence of depression symptoms among participants was 24%. Participants who were women, were in older age groups, had multimorbidity, lived in isolated Portuguese regions such as islands and Alentejo, and were retired or unemployed more frequently reported depression symptoms. Economic hardship was also found to be associated with an increased frequency of mild or moderate-to-severe depression. In contrast, higher levels of education, regular alcohol intake, and regular exercise were associated with a lower frequency of depression symptoms. Conclusions: These findings highlight that during the third wave of the COVID-19 pandemic, a high proportion of Portuguese adults reported depression symptoms, particularly the COVID-19-vulnerable strata such seniors, patients with multimorbidity, and people in economic hardship. On the other hand, citizens who performed regular physical exercise reported lower depressive symptomology. Our work contributes to improving the planning of mental health promotion after the COVID-19 pandemic and future emergencies.publishersversionpublishe

    Non-global logarithms and jet algorithms in high-pT jet shapes

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    We consider jet-shape observables of the type proposed recently, where the shapes of one or more high-pT jets, produced in a multi-jet event with definite jet multiplicity, may be measured leaving other jets in the event unmeasured. We point out the structure of the full next-to-leading logarithmic resummation specifically including resummation of non-global logarithms in the leading-Nc limit and emphasising their properties. We also point out differences between jet algorithms in the context of soft gluon resummation for such observables.Comment: 22 pages, 4 figures. Title and a few words changed. Several typos corrected. Version accepted by JHE

    Diboson-Jets and the Search for Resonant Zh Production

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    New particles at the TeV-scale may have sizeable decay rates into boosted Higgs bosons or other heavy scalars. Here, we investigate the possibility of identifying such processes when the Higgs/scalar subsequently decays into a pair of W bosons, constituting a highly distinctive "diboson-jet." These can appear as a simple dilepton (plus MET) configuration, as a two-prong jet with an embedded lepton, or as a four-prong jet. We study jet substructure methods to discriminate these objects from their dominant backgrounds. We then demonstrate the use of these techniques in the search for a heavy spin-one Z' boson, such as may arise from strong dynamics or an extended gauge sector, utilizing the decay chain Z' -> Zh -> Z(WW^(*)). We find that modes with multiple boosted hadronic Zs and Ws tend to offer the best prospects for the highest accessible masses. For 100/fb luminosity at the 14 TeV LHC, Z' decays into a standard 125 GeV Higgs can be observed with 5-sigma significance for masses of 1.5-2.5 TeV for a range of models. For a 200 GeV Higgs (requiring nonstandard couplings, such as fermiophobic), the reach may improve to up to 2.5-3.0 TeV.Comment: 23 pages plus appendices, 9 figure
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