7,225 research outputs found

    Lax orthogonal factorisation systems

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    This paper introduces lax orthogonal algebraic weak factorisation systems on 2-categories and describes a method of constructing them. This method rests in the notion of simple 2-monad, that is a generalisation of the simple reflections studied by Cassidy, H\'ebert and Kelly. Each simple 2-monad on a finitely complete 2-category gives rise to a lax orthogonal algebraic weak factorisation system, and an example of a simple 2-monad is given by completion under a class of colimits. The notions of KZ lifting operation, lax natural lifting operation and lax orthogonality between morphisms are studied.Comment: 59 page

    Web Acceptance and Usage Model: A Comparison between Goal-directed and Experiential Web Users

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    In this paper we analyse the Web acceptance and usage between goal-directed users and experiential users, incorporating intrinsic motives to improve the particular and explanatory TAM value –traditionally related to extrinsic motives-. A field study was conducted to validate measures used to operationalize model variables and to test the hypothesised network of relationships. The data analysis method used was Partial Least Squares (PLS).The empirical results provided strong support for the hypotheses, highlighting the roles of flow, ease of use and usefulness in determining the actual use of the Web among experiential and goal-directed users. In contrast with previous research that suggests that flow would be more likely to occur during experiential activities than goal-directed activities, we found clear evidence of flow for goal-directed activities. In particular the study findings indicate that flow might play a powerfulrole in determining the attitude towards usage,intention to useand, in turn,actual Web use among experiential and goal-directed users

    Classification of high dimensional data using LASSO ensembles

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    Urda, D., Franco, L. and Jerez, J.M. (2017). Classification of high dimensional data using LASSO ensembles. Proceedings IEEE SSCI'17, Symposium Series on Computational Intelligence, Honolulu, Hawaii, U.S.A. (2017). ISBN: 978-1-5386-2726-6The estimation of multivariable predictors with good performance in high dimensional settings is a crucial task in biomedical contexts. Usually, solutions based on the application of a single machine learning model are provided while the use of ensemble methods is often overlooked within this area despite the well-known benefits that these methods provide in terms of predictive performance. In this paper, four ensemble approaches are described using LASSO base learners to predict the vital status of a patient from RNA-Seq gene expression data. The results of the analysis carried out in a public breast invasive cancer (BRCA) dataset shows that the ensemble approaches outperform statistically significant the standard LASSO model considered as baseline case. We also perform an analysis of the computational costs involved for each of the approaches, providing different usage recommendations according to the available computational power.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Novel Ruthenium-Silver PTA-Based Polymers and Their Behavior in Water

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    New coordination polymers based on two metal-containing moieties Ru–Ag are synthesized: Na[RuCpX(PTA)-μ-(PTA)-1κP:2κ2N-AgX2]∞ (X = Cl (1), Br (2), I (3)). Characterization is performed by NMR, UV-visible and FT-IR spectroscopy, optical-electron microscopy, and elemental analyses (C, H, N, S). Light scattering is employed to characterize the colloidal particles growth by polymer self-assembling. These structures are stable over a broad range of pH and exhibit thermally-driven swelling, thus resembling a typical thermosensitive hydrogel

    Hypothalamic and mesencephalic regions involved in the control of laryngeal activity and subglottic pressure in spontaneously breathing anaesthetized rats

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    Changes of laryngeal caliber allow changes in airflow which are necessary for the vibration of the vocal folds and emission of voice. It is known that stimulation of the Periaqueductal Gray matter (PAG) and nucleus retroambiguus (nRA) produces vocalization, and lesions in PAG cause mutism in animals and humans. The nRA is the perfect target to turn passive into active expiration modifying the activity of laryngeal motoneurons located in the nucleus ambiguous (Paton and Nolan, 2000). We have shown that rostral and ventral pontine structures are involved in changes of laryngeal caliber (Lara et al., 2002). It has been also demonstrated a high expression of FOXP2 protein (transcription factor related to vocalization) at mesencephalic and pontine regions (PAG, Parabrachial complex and A5 Region) involved in cardiorespiratory control. The aim of this study was to characterize the relations between hypothalamic and mesencephalic regions involved in cardiorespiratory control and their possible role in modulating laryngeal activity. Experimental studies were carried out with non-inbred male rats (n=7), SPF, Sprague-Dawley (250-300 g) housed under standard conditions. Animals were anesthetized with sodium pentobarbitone (60 mg/kg i.p., initial dose, supplemented 2 mg/kg, i.v., as necessary). A double tracheal cannulation to develop the classical technique of the “glottis isolated in situ” and for the recording of respiratory airflow was carried out. DMH-PeF, dlPAG, and CnF stimulations evoked a significant decrease of laryngeal resistance (subglottal pressure) (p<0.01) accompanied with an inspiratory facilitatory response consisted of an increase in respiratory rate, together with a pressor and tachycardic response. The results of our study contribute with new data on the role of the hypothalamic-mesencephalic neuronal circuits in the control mechanisms of subglottic pressure and laryngeal activity.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Characterization of the Neutron Irradiation System for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories

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    The objective of this work was to characterize the neutron irradiation system consisting of americium 241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential experimental configurations and neutron spectra for component irradiation. The final product of this work is a MCNP model validated by measurements, an overall understanding of neutron irradiation system including photon/neutron transport and effective dose rates throughout the system, and possible experimental configurations for future irradiation of components

    Surgimiento y conformación de bandas emergentes. Conformación y confrontación de las bandas emergentes

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    De décadas pasadas el País ha venido experimentando múltiples manifestaciones criminales, generadoras de violencia y que han entorpecido el crecimiento económico y social, inicialmente se dan los movimientos de autodefensas campesinas que a mediados del siglo anterior dieron origen a los grupos subversivos, posterior a ellos surgen los grupos de autodefensas (paramilitares) con el propósito de realizar una lucha contra subversiva, su actuar criminal dejo un mal aprendizaje tanto en la población civil como en los combatientes, estos últimos que posterior a la desmovilización y pese a los esfuerzos gubernamentales no hallaron camino diferente a continuar con su actuar criminal. En el fenómeno BACRIM se ha dado un reciclaje de especialistas en el uso de las armas, en el grado de subordinación que los diferentes bloques de las AUC habían logrado y las limitaciones y retraso de la política de reintegración para enfrentar ese reciclaje encaminado al trafico de drogas, extorciones entre otras actividades ilícitas, lo que ha permitido a estos grupos delincuenciales un acrecentamiento y fortalecimiento en su actuar criminal.For decades our country has been experiencing multiple criminal manifestations, generating violence and that they have hampered the economic and social growth, initially given the movements of peasant self-defense groups that in the middle of the previous century gave rise to subversive groups, subsequently arise the groups of self-defense (paramilitary) for the purpose of making a fight against subversive emerge back to them. their criminal actions leave one bad learning both, in the civilian population as combatants, these last that later to demobilization and despite the Government's efforts did not find different path that continue with his criminal act. In the BACRIM phenomenon, is given a recycling of specialists in the use of weapons, in the degree of subordination that the different blocks of the AUC had been achieved and the limitations and delay of the reintegration policy to face the recycling intended to the drugs traffic, extortion among other illicit activities, which allowed these criminal groups an enhancement and strengthening in his criminal act

    Ruína del convento de San Francisco en Santo Domingo : análisis y recuperación

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    Análisis arquitectónico de edificios históricos de la República Dominicana. Curso de Manuel Franco Taboada Master de Arquitectura UDC-PUCMM República DominicanaEste estudio está vinculado al proyecto de investigación «Encuentros, intercambios y presencias en Galicia entre los siglos XVI y XX» (HAR2011-22899) y al «Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas» (GRC2013-036)
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