1,284 research outputs found

    Multisensory causal inference in the brain

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    At any given moment, our brain processes multiple inputs from its different sensory modalities (vision, hearing, touch, etc.). In deciphering this array of sensory information, the brain has to solve two problems: (1) which of the inputs originate from the same object and should be integrated and (2) for the sensations originating from the same object, how best to integrate them. Recent behavioural studies suggest that the human brain solves these problems using optimal probabilistic inference, known as Bayesian causal inference. However, how and where the underlying computations are carried out in the brain have remained unknown. By combining neuroimaging-based decoding techniques and computational modelling of behavioural data, a new study now sheds light on how multisensory causal inference maps onto specific brain areas. The results suggest that the complexity of neural computations increases along the visual hierarchy and link specific components of the causal inference process with specific visual and parietal regions

    Icon: A diagrammatic theorem prover for ontologies

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    Concept diagrams form a visual language that is aimed at non-experts for the specification of ontologies and reason- ing about them. Empirical evidence suggests that they are more accessible to ontology users than symbolic notations typically used for ontologies (e.g., DL, OWL). Here, we re- port on iCon, a theorem prover for concept diagrams that al- lows reasoning about ontologies diagrammatically. The input to iCon is a theorem that needs proving to establish how an entailment, in an ontology that needs debugging, is caused by a minimal set of axioms. Such a minimal set of axioms is called an entailment justification. Carrying out inference in iCon provides a diagrammatic proof (i.e., explanation) that shows how the axioms in an entailment justification give rise to the entailment under investigation. iCon proofs are for- mally verified and guaranteed to be correct.Zohre

    Deductive reasoning about expressive statements using external graphical representations

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    Research in psychology on reasoning has often been restricted to relatively inexpressive statements involving quantifiers. This is limited to situations that typically do not arise in practical settings, such as ontology engineering. In order to provide an analysis of inference, we focus on reasoning tasks presented in external graphic representations where statements correspond to those involving multiple quantifiers and unary and binary relations. Our experiment measured participants’ performance when reasoning with two notations. The first used topology to convey information via node-link diagrams (i.e. graphs). The second used topological and spatial constraints to convey information (Euler diagrams with additional graph-like syntax). We found that topological- spatial representations were more effective than topological representations. Unlike topological-spatial representations, reasoning with topological representations was harder when involving multiple quantifiers and binary relations than single quantifiers and unary relations. These findings are compared to those for sentential reasoning tasks

    Exploring and conceptualising attestation

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    When formalising the rules of trust in the remote attesta- tion of TPM-based computer systems it is paramount that the rules are precisely understood, supporting unambiguous communication of infor- mation about system requirements between engineers. We present a dia- grammatic approach to modelling rules of trust using an extended version of concept diagrams. Within the context of our proof-of-concept Net- work Function Virtualisation and Attestation environment, these rules allow different level of trust to be explored and, importantly, allow us to identify when a computer system should not be trusted. To ensure that the modelling approach can be applied to general systems, we in- clude generic patterns for extending our domain model and rules of trust. Consequently, through the use of a formal, yet accessible, diagrammatic notation, domain experts can define rules of trust for their systems.Leverhulme Trust gran

    Tunable Optical Assembly with Vibration Dampening

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    Since their market introduction in 1995, fiber Bragg gratings (FBGs) have emerged as excellent means of measuring such parameters as strain and temperature. Distributed-grating sensing is particularly beneficial for such structural-health monitoring applications such as those of 'smart' structures or integrated vehicle health management in aerospace vehicles. Because of the variability of their output wavelengths, tunable lasers have become widely used as means of measuring FBGs. Several versions of a lightweight assembly for strain-tuning an FBG and dampening its vibrations have been constructed. The main components of such an assembly are one or more piezoelectric actuators, an optical fiber containing one or more Bragg grating(s), a Bragg-grating strain-measurement system, and a voltage source for actuation. The piezoelectric actuators are, more specifically, piezoceramic fiber composite actuators and, can be, still more specifically, of a type known in the art as macro-fiber composite (MFC) actuators. In fabrication of one version of the assembly, the optical fiber containing the Bragg grating(s) is sandwiched between the piezoelectric actuators along with an epoxy that is used to bond the optical fiber to both actuators, then the assembly is placed in a vacuum bag and kept there until the epoxy is cured. Bonding an FBG directly into an MFC actuator greatly reduces the complexity, relative to assemblies, that include piezoceramic fiber composite actuators, hinges, ferrules, and clamp blocks with setscrews. Unlike curved actuators, MFC actuators are used in a flat configuration and are less bulky. In addition, the MFC offers some vibration dampening and support for the optical fiber whereas, in a curved piezoelectric actuator assembly, the optical fiber is exposed, and there is nothing to keep the exposed portion from vibrating

    Reference concentrations for trace elements in urine for the Brazilian population based on q-ICP-MS with a simple dilute-and-shoot procedure

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    Biomonitoring of trace elements is of critical importance in human health assessment. However, trace element concentrations in biological fluids are affected by environmental and physiological parameters, and therefore considerable variations can occur between specific population subgroups. Brazil is a large country with large environmental diversity and with a limited knowledge of the reference values (baseline data) for trace elements in biological fluids. Atomic absorption spectrometry (AAS) and inductively coupled plasma emission spectrometry (ICP-OES) are still the dominant analytical techniques used for biomonitoring trace element analysis in clinical specimens. However, the use of ICP-MS is becoming more usual in clinical laboratory analysis. Then, we evaluated here a simple dilute-and-shoot method for sequential determination of Al, Ba, Be, Cd, Co, Cu, Cs, Mn, Ni, Pb, Pt, Sb, Se, Sn, Tl and U in urine by quadrupole inductively coupled plasma mass spectrometry (q-ICP-MS). Urine samples (500 µL) were accurately pipetted into conical tubes (15 mL) and diluted to 10 mL with a solution containing 0.5 % (v/v) HNO3 + 0.005% (v/v) Triton X-100. Diluted urine samples also contain rhodium, iridium and yttrium added as internal standards. After that, samples were directly analyzed by ICP-MS against matrix-matching calibration. Method detection limit (3s, n = 20) were in the ng L-1 range for all analytes. The method was applied to the analysis of 412 ordinary urine samples from Brazilian healthy and non-exposed subjects to establish reference values. Data validation was provided by the analysis of the standard reference material (SRM) 2670a toxic elements in urine (freeze-dried) (high and low levels) from the National Institute of Standards and Technology (NIST) and reference urine samples from the trace elements intercomparison program operated by the Institut National de Sante' Publique du Quebec, Canada.O biomonitoramento de elementos químicos é de extrema importância na avaliação da saúde humana. Entretanto, as concentrações dos elementos químicos nos fluidos biológicos são afetadas por parâmetros ambientais e fisiológicos e, consequentemente, consideráveis variações podem ocorrer entre subgrupos de populações específicas. O Brasil é um país com ampla diversidade ambiental e existe limitado conhecimento de valores de referência para elementos químicos em fluidos biológicos. A espectrometria de absorção atômica (AAS) e a espectrometria de emissão ótica com plasma acoplado indutivamente (ICP-OES) ainda são as técnicas analíticas mais comumente empregadas no biomonitoramento de elementos químicos em amostras clínicas. Entretanto, o uso da espectrometria de massas com plasma acoplado indutivamente (ICP-MS) está se tornando a cada dia mais comum nos laboratórios clínicos. Neste estudo, foi avaliado um método rápido envolvendo simples diluição da amostra para determinação de Al, Ba, Be, Cd, Co, Cu, Cs, Mn, Ni, Pb, Pt, Sb, Se, Sn, Tl e U em urina por ICP-MS. Amostras de urina (500 μL) foram pipetadas em frascos cônicos de 15 mL e diluídas para 10 mL com uma solução contendo 0,5 % (v/v) HNO3 + 0,005% (v/v) Triton X-100. Ródio, irídio e ítrio foram adicionados como padrões internos. Em seguida, as amostras foram diretamente analisadas por ICP-MS com calibração por ajuste de matriz. Os limites de detecção do método (3s, n = 20) foram da ordem de ng L-1 para todos os analitos em estudo. O método foi aplicado para a análise de 412 amostras de urina de brasileiros saudáveis e não expostos ambientalmente ou ocupacionalmente a metais para o estabelecimento de valores de referência na população brasileira. A validação dos resultados foi acompanhada pela análise de material de referência certificada de urina (SRM) 2670a proveniente do National Institute of Standards and Technology (NIST) e de materiais de referência provenientes do Institut National de Sante' Publique Du Quebec, no Canadá.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Relationships between self-efficacy and pap smear screening in Iranian women

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    Cervical cancer is the fourth common cancer among women worldwide. Pap smear screening has resulted in deceasing incidence of cervical cancer in developed countries but low uptake of Pap smear screening among women in developing countries is still a public health challenge. The aim of this cross-sectional study was to assess the relationship between self-efficacy and timely uptake of Pap smear among Iranian women. A total of 580 married women referred to primary health care centers covered administratively by Shahid Beheshti University of Medical Sciences in Tehran were administered a questionnaire by trained staff. Data were analyzed with SPSS (version 16) software, using univariate and multivariate logistic regression. The mean age for participants was 33.1±8.8 years. There was a significant association between self-efficacy and Pap smear screening (P < 0.01). There was also a positive correlation between duration of marriage and husband's education with Pap smear uptake (P < 0.01). In univariate analysis, there was a significant association between Pap smear uptake and level of self-efficacy (OR = 15.3 for intermediate and OR=7.4 for good level), duration of marriage (OR = 5.7 for 5-14 years and OR=10.4 for more than 15), age (OR =2.7 for 27-34 years and OR=7.4 for more than 35 years) and husband education level (OR=2.3 for more than 12 years of education). In multivariate analysis, significant associations persisted between Pap smear uptake and self-efficacy (OR = 23.8; 95 CI: 8.7, 65.5), duration of marriage (OR = 5.9; 95 CI: 2.8, 12.2), age (OR = 3.9; 95 CI: 1.2, 12.9) and husband's education (OR = 2.5; 95 CI: 2.0, 10.3). Efforts are needed to increase women's knowledge about cervical cancer and improve their self-efficacy and perceptions of the Pap smear screening in order to reduce cervical cancer incidence and mortality rates. © 2016, Asian Pacific Journal of Cancer Prevention
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