2,038 research outputs found
Dispersion cancellation and quantum eraser experiments analyzed in the Wigner function formalism
We extend the Wigner function formalism for parametric down-conversion experiments presented in a previous paper [Phys. Rev. A 55 3879 (1997)] to experiments involving propagation through a dispersive medium [Steinberg et al., Phys. Rev. A 45, 6659 (1992)], and polarization [Kwiat et al., Phys. Rev. A 45, 7729 (1992)]
Quantitative taphonomy of the Cacela site (late Tortonian; Algarve, S Portugal)
A quantitative taphonomic analysis were performed in the fossil assemblages of the late Tortonian of the
lower-mid part of the Cacela Formation (Cacela, Algarve, S Portugal). Taphonomic results, together with
sedimentological analysis and the faunal assemblages, allow to inferring palaeoenvironmental changes.
The upper Tortonian sedimentation started with fan-delta conglomerates that quickly changed to outerplatform
silty marls deposited in a setting with a relatively low sedimentation rate as indicated by the
concentration of glauconite. Higher up into the section, a progressive shallowing trend is inferred, and
sediments of inner platform settings were forme
Un nuevo ensayo para la evaluación de los encolados composite-composite
VI CONGRESO NACIONAL DE MATERIALES COMPUESTOS. Celebrado en
Valencia, 27-29 de junio de 2005En el presente trabajo se propone una nueva configuración de ensayo para la
determinación de la tenacidad a fractura interlaminar GIC en encolados compositecomposite.
Las configuraciones actuales que fijan las normas de ensayo para la
determinación de GIC se realizan de forma que la carga no permanece constante y el
cálculo de GIC queda altamente dependiente de las propiedades de los adherentes,
parámetros geométricos y demás variables que no representan la calidad del encolado ni
la preparación superficial. La configuración propuesta origina el avance de la grieta de
interfase bajo una carga media constante y pretende corregir las limitaciones
mencionadas
Physical and psychological paths toward less severe fibromyalgia: A structural equation model
The authors gratefully acknowledge all the participants for their
collaboration and enthusiasm. We thank the assistant researchers
involved in this study and all the members of the Physical Activity
for HEaLth Promotion (PA-HELP; CTS-1018) research group.Supplementary data associated with this article can be found, in
the online version, at https://doi.org/10.1016/j.rehab.2019.06.017.Objectives: Previous research suggested isolated associations of physical and psychological factors with
fibromyalgia severity. Integration of physical and psychological, experienced and observed, modifiable
factors associated with fibromyalgia severity in a single model will reveal therapeutic paths toward less
severity of disease. We aimed to examine an encompassing model of determinants of fibromyalgia
severity.
Methods: This observational, population-based cross-sectional study included 569 people with
fibromyalgia. An integrative model of fibromyalgia severity was tested by using structural equation
modelling. This model included 8 factors: resilience, catastrophizing, active lifestyle, declarative
memory, subjective fitness, objective fitness, psychological distress, and physical fatigue.
Results: Two core paths were associated with reduced fibromyalgia severity: 1) a psychological path
connecting high resilience and low catastrophizing with low distress and 2) a physical path, connecting a
more active lifestyle (directly and via high objective and subjective physical fitness) with low fatigue.
Additional interconnecting paths especially suggested a connection from the psychological to physical
path. Our model explained 83% of the fibromyalgia severity.
Conclusions: The present model integrated the complexity of mutually influencing factors of fibromyalgia
severity, which may help to better understand the disease. It emphasised the importance of: 1) physical
factors and psychological factors and their interconnections, 2) patients’ experiences and clinical
measurements, and 3) positive and negative signs such as physical fitness and distress. Future
longitudinal and experimental research should aim at testing the causal direction of the associations in
the model as well as the clinical implications suggested by the model. For instance, to reduce fatigue,
exercise should enhance not only objective fitness but also fitness-related perceptions. Reducing distress
and fatigue seems crucial for lowering fibromyalgia severity.This work was supported by the Spanish Ministry of Economy and Competitiveness [I+D+i DEP2010-15639, I+D+I DEP2013-40908, I+D+I PSI2015-65241-R, and BES-2014-067612] and the Spanish Ministry of Education [FPU15/00002]. This study was funded in part by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades and European Regional Development Fund (ref. SOMM17/6107/UGR) and University of Jaén, Plan de Apoyo a la Investigación 2017-2019 [EI_SEJ07_2017]. The funders did not have any role in the study design, data collection and analyses, decision to publish, or preparation of the manuscript
Classification methods to identify lesions in skin starting from spectra of diffuse reflectance
Con el objetivo de discriminar lesiones benignas y malignas en la piel humana a partir de espectros de reflexión
difusa, se han analizado diferentes algoritmos de clasificación usando el software de aprendizaje automático y reconocimiento de
patrones WEKA. Además, dada la alta dimensionalidad de la señal espectral, fue empleada una técnica selección de atributos para
determinar las variables que aporten la mayor cantidad de información. Se probó la clasificación de la señal usando los algoritmos
de máquinas de vectores de soporte, redes neuronales y bosques aleatorios, el desempeño fue evaluado usando el promedio de la
k-fold cross-validation tomando en cuenta los porcentajes de instancias clasificadas correctamente, el índice kappa, el área bajo
la curva ROC, la sensibilidad, y la especifidad. Finalmente se demuestra que el algoritmo de redes neuronales con los parámetros
momentum y learning rate en 0,6 y 0,3 respectivamente, es el que mejor se adapta al problema de reconocimiento de patrones ya
que clasifica correctamente al 89,89% de los casos.In order to differentiate between benign and malignant lesions in the human skin using diffuse reflection spectra,
different classification algorithms were tested using the WEKA data mining software. In addition, due to the high dimensionality
of the spectral signal, an attribute selection technique was applied to determine the variables that contribute with more information.
The spectral signal classification was tested using support vector machines, neural networks and random forests, their performance
was measured using the k-fold cross-validation percentages of the Kappa statistic, area under the ROC curve, specificity and
sensitivity. Finally it is shown that the one layer neural network with 6 neurons and the parameters momentum and learning rate
in 0.6 and 0.3 respectively, is best suited to the problem of pattern recognition, achieving correctly classify 89.89% of the cases
Identification of candidate genes associated with fibromyalgia susceptibility in southern Spanish women: the al‑Ándalus project
Candidate-gene studies on fibromyalgia susceptibility often include a small number of single nucleotide
polymorphisms (SNPs), which is a limitation. Moreover, there is a paucity of evidence in Europe. Therefore, we
compared genotype frequencies of candidate SNPs in a well-characterised sample of Spanish women with fibromyalgia
and healthy non-fibromyalgia women.This work was supported by the Spanish Ministry of Economy and Competitiveness
[I+D+i DEP2010-15639, I+D+i DEP2013-40908-R to M.D.-F.;
BES-2014-067612 to F.E.-L.]; the Spanish Ministry of Education [FPU2014/02518
to M.B.-C.]; the Consejería de Turismo, Comercio y Deporte, Junta de Andalucía
[CTCD-201000019242-TRA to M.D.-F.]; Consejería de Salud, Junta de Andalucía
[PI-0520-2016 to M.D.-F.], and the University of Granada, Plan Propio de
Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence
on Exercise and Health (UCEES). This work is part of a Ph.D. Thesis conducted
in the Biomedicine Doctoral Studies of the University of Granada, Spai
Coverage of highly-cited documents in Google Scholar, Web of Science, and Scopus: a multidisciplinary comparison
This study explores the extent to which bibliometric indicators based on counts of highly-cited documents could be affected by the choice of data source. The initial hypothesis is that databases that rely on journal selection criteria for their document coverage may not necessarily provide an accurate representation of highly-cited documents across all subject areas, while inclusive databases, which give each document the chance to stand on its own merits, might be better suited to identify highly-cited documents. To test this hypothesis, an analysis of 2,515 highly-cited documents published in 2006 that Google Scholar displays in its Classic Papers product is carried out at the level of broad subject categories, checking whether these documents are also covered in Web of Science and Scopus, and whether the citation counts offered by the different sources are similar. The results show that a large fraction of highly-cited documents in the Social Sciences and Humanities (8.6%-28.2%) are invisible to Web of Science and Scopus. In the Natural, Life, and Health Sciences the proportion of missing highly-cited documents in Web of Science and Scopus is much lower. Furthermore, in all areas, Spearman correlation coefficients of citation counts in Google Scholar, as compared to Web of Science and Scopus citation counts, are remarkably strong (.83-.99). The main conclusion is that the data about highly-cited documents available in the inclusive database Google Scholar does indeed reveal significant coverage deficiencies in Web of Science and Scopus in several areas of research. Therefore, using these selective databases to compute bibliometric indicators based on counts of highly-cited documents might produce biased assessments in poorly covered areas.Alberto Martín-Martín enjoys a four-year doctoral fellowship (FPU2013/05863) granted by the Ministerio de Educación, Cultura, y Deportes (Spain)
Fourth-order interference in the Wigner representation for parametric down-conversion experiments
In the Wigner formalism, after giving a general description of a light beam, the theory of parametric down-conversion is developed to second-order in the coupling constant. We then describe the detection process by calculating the auto-correlation and cross-correlations of the signal and idler beams. Four recent experiments are analyzed in detail: interference on a screen, Franson's experiments [Phys. Rev. Lett. 62, 2205 (1989)], Rarity and Tapster's experiments [Phys. Rev. Lett. 64, 2495 (1990)], and induced coherence without induced emission [X. Y. Zou, L. J. Wang, and L. Mandel, Phys. Rev. Lett. 67, 318 (1991)]
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