752 research outputs found

    Seasonal concentration of tourism demand: decomposition analysis and marketing implications

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    This paper analyzes seasonality in the United Kingdom, specifically the English regions in relation to tourists’ place of origin and main travel motivation. The method used is a decomposition of the Gini index, which provides relative marginal effects that facilitate the identification of market segments open to counter-seasonal marketing efforts. This method has been combined with a graphical multivariate technique (biplot), which groups segments according to their seasonality characteristics. Seasonal patterns associated with particular segments differ significantly when studied on a disaggregated basis. Therefore, an adequate level of disaggregation is essential in the design of counter-seasonal strategies. Although this study focuses on British destinations, this methodology could be used as a control and monitoring measure in the regional analysis of any destination, facilitating regular adjustment of regional tourism marketing campaigns to minimize seasonality effects, specifically by targeting the types of tourists less prone to seasonality

    Synthesis of Curved Surface Plasmon Fields through Thin Metal Films in a Tandem Array

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    We describe the generation of plasmonic modes that propagate in a curved trajectory inducing magnetic properties. This is performed by masking a metal surface with two screens containing a randomly distributed set of holes that follow a Gaussian statistic. The diameter of the holes is less than the wavelength of the illuminating plane wave. By implementing scaling and rotations on each screen, we control the correlation trajectory and generate long-range curved plasmonic modes. Using the evanescent character of the electric field, the study is implemented for the transmission of a plasmonic mode propagating in a tandem array of thin metal films offering the possibility to generate localization effects

    Assessing The Students’ Prospective Perceptions Of The Final Master Project In Actuarial Science

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    The final master project plays a key role in the curriculum design of the Actuarial Science Master degree at the University of Málaga. Students have to fulfil their projects at the end of the two-years study program in order to get the master’s degree. The nature of the projects requires the combination of a wide range of skills, which includes analytical and technical ones, as well as professional and soft skills. From this point of view, completing a final master project in this study program can become an interesting opportunity to experiment with real tasks of the actuarial profession before entering the labour market. Furthermore, the Actuarial Science Master degree at the University of Málaga offers the possibility of including a working actuary as a second supervisor, besides the academic one. Simulating or working with real problems in the field of Actuarial Science in the final master project, which use to be complex in nature and often multidisciplinary, also constitutes a useful way to integrate the contents of the different courses of the study program and get them in context. However, the quick transition of our students to the professional market, mainly through the internships, sometimes becomes a hurdle to properly finish the final projects in the scheduled academic calendar. In an attempt to improve the satisfaction and success rates, a group of lecturers are conducting a broad study about the final master project in Actuarial Science, that includes subjective aspects.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Fibronectin modulates the endocannabinoid system through the cAMP/PKA pathway during human sperm capacitation

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    Fibronectin (Fn) enhances human sperm capacitation via the cAMP/PKA pathway, and the endocannabinoid system participates in this process. Moreover, Fn has been linked to endocannabinoid system components in different cellular models, even though no evidence of such interactions in human sperm is available. Normal semen samples were evaluated over a 4-year period. Our findings suggest that (a) the capacitating effects of Fn were reversed by preincubating the sperm with a cannabinoid receptor 1 (CB1) or transient receptor potential cation channel subfamily V member 1 (TRPV1) antagonist (p < 0.001 and p < 0.05, respectively); (b) cooperation between CB1 and TRPV1 may exist (p < 0.01); (c) the activity of specific fatty acid amide hydroxylase (FAAH) decreased after 1 min (p < 0.01) and increased after 60 min (p < 0.01) of capacitation in the presence of Fn; (d) the effects of Fn on FAAH activity were prevented by preincubating spermatozoa with a protein kinase A (PKA) inhibitor (p < 0.01); (e) Fn modulated both the cyclic adenosine monophosphate concentration and PKA activity (p < 0.05) during early capacitation; and (f) FAAH was a PKA substrate modulated by phosphorylation. These findings indicate that Fn stimulates human sperm capacitation via the cAMP/PKA pathway through modulation of the endocannabinoid system. Understanding the functional competence of human spermatozoa is essential for facilitating clinical advances in infertility treatment and for developing novel contraceptive strategies.Fil: Martínez León, Eduardo Antonio. Universidad de Antofagasta; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Osycka Salut, Claudia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Signorelli, Janetti. Universidad de Antofagasta; ChileFil: Kong, Milene. Universidad de Antofagasta; ChileFil: Morales, Patricio. Universidad de Antofagasta; ChileFil: Perez Martinez, Silvina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Díaz, Emilce Silvina. Universidad de Antofagasta; Chil

    Use of recycled aluminum - polyethylene composite films as anodic electrodes for electrocoagulation of wastewater

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    artículo para uso de películas de aluminio polietilenoThis work evaluates the use of aluminum contained in the aluminum-polyethylene films as anodic electrodes using the electrocoagulation technique to reduce the pollutants contents of an industrial wastewater quickly and effectively. Two different current densities were applied 25 and 12.5 mA cm-2. When the current density of 25 mA cm-2 is used, the aluminum electrodes reduce the COD of wastewater by about 65% and the aluminum-polyethylene films electrodes reduces the COD by 56%. The color and turbidity reductions are 87 and 90% respectively. The use of aluminum-polyethylene films as electrodes in the electrocoagulation process contributes to the pollutant removal without the addition of chemical reagents or changing the pH, so it is both effective and environmentally friendly.Centro Conjunto de Investigación en Química Sustentable, UAEM-UNAM, CONACYT, UAEMe

    1D and 3D supramolecular structures exhibiting weak ferromagnetism in three Cu(II) complexes based on malonato and di-alkyl-2,2’-bipyridines

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    Abstract Manganese coordination polymers {Mn(- fum)(5dmb)(H2O)2}n (1) and {[Mn2(fum)2(4dmb)2] H2O}n (2) (fum= fumarato; 5dmb = 5,50-dimethyl-2,20-bipyridine; 4dmb = 4,40-dimethyl-2,20-bipyridine) were obtained from one-pot, solution reactions under ambient conditions. The fum ligand acquires different coordination modes in the presence of the different dmb ancillary ligands, promoting distinctive crystal structures, including divergent dimensionalities. Thus, X-ray single-crystal data reveal that complex 1 crystallizes in a monoclinic system with C2/c space group and forms an infinite one-dimensional polymer. The Mn(II) center is six-coordinated and displays a distorted octahedral configuration. In addition, the solid-state selfassembly of the polymeric structure of 1 gives rise to a twodimensional (2D) supramolecular framework, mainly through hydrogen bonding. In contrast, complex 2 crystallizes in a monoclinic system with a Cc space group and forms an infinite 2D coordination polymer having dinuclear units. The Mn(II) center has a distorted octahedral configuration. The thermal stabilities of both coordination polymers were investigated. Variable-temperature magnetic measurements show that complex 1 is paramagnetic, while complex 2 exhibits weak antiferromagnetic coupling between adjacent Mn(II) centers.supported by CONACyT project 129293, DGAPA-UNAM project IN106014, and ICYTDF, project PICCO

    Degradation of 4-Chlorophenol in a Batch Electrochemical Reactor Using BDD Electrodes

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    The influence of current density (j) (0.25, 0.30, 0.25 and 0.40 A/cm2), initial pH (2.6, 6.5 and 12), stirring speed (As) (400, 500 and 600 rpm), and initial concentration of 4-chlorophenol ([4-CP]0) (300, 500 and 700 mg/L) on degradation of persistent pollutant in a batch electrochemical cell without divisions is presented in this paper. The electrochemical cell was composed of two boron-doped diamond electrodes (BDD). The results of the study showed that best conditions for total degradation of 4-CP were: j of 0.40 A/cm , initial pH of 6.5, As of 500 rpm, and [4-CP]0 of 500 mg/L, after 150 min of reaction time. Removal of total organic carbon (TOC) was 83% at these conditions. The byproducts were identified by UHPLC. This allowed for the proposal of a degradation pathway of 4-CP at the best conditions. Furthermore, these results demonstrate that the electrochemical method employed in this study allows high percentages (96%) of degradation of 4-CP and that the process is applicable to wastewater treatment.CONACYT 26909

    Improving deep learning performance with missing values via deletion and compensation

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    Proceedings of: International Work conference on the Interplay between Natural and Artificial Computation (IWINAC 2015)Missing values in a dataset is one of the most common difficulties in real applications. Many different techniques based on machine learning have been proposed in the literature to face this problem. In this work, the great representation capability of the stacked denoising auto-encoders is used to obtain a new method of imputating missing values based on two ideas: deletion and compensation. This method improves imputation performance by artificially deleting values in the input features and using them as targets in the training process. Nevertheless, although the deletion of samples is demonstrated to be really efficient, it may cause an imbalance between the distributions of the training and the test sets. In order to solve this issue, a compensation mechanism is proposed based on a slight modification of the error function to be optimized. Experiments over several datasets show that the deletion and compensation not only involve improvements in imputation but also in classification in comparison with other classical techniques.The work of A. R. Figueiras-Vidal has been partly supported by Grant Macro-ADOBE (TEC 2015-67719-P, MINECO/FEDER&FSE). The work of J.L. Sancho-Gómez has been partly supported by Grant AES 2017 (PI17/00771, MINECO/FEDER)

    Pretreatment of Real Wastewater from the Chocolate Manufacturing Industry through an Integrated Process of Electrocoagulation and Sand Filtration

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    En este artículo se analizó el efecto de un proceso acoplado de electrocoagulación y filtración, para remover partículas suspendidas en un agua residual procedente de una industria de chocolates.The purpose of this study was to evaluate the efficiency of removal of suspended solids in terms of turbidity, color, and chemical oxygen demand (COD) when integrating the electrocoagulation process using aluminum sacrificial anodes and the sand filtration process as a pretreatment of wastewater from the chocolate manufacturing plant in Toluca, México. Wastewater from the chocolate manufacturing industry used in this study is classified as nontoxic, but is characterized as having a high content of color (5952 ± 76 Pt-Co), turbidity (1648 ± 49 FAU), and COD (3608 ± 250 mg/L). Therefore, enhanced performance could be achieved by combining pretreatment techniques to increase the efficiencies of the physical, chemical, and biological treatments. In the integrated process, there was a turbidity reduction of 96.1 ± 0.2% and an increase in dissolved oxygen from 3.8 ± 0.05 mg/L (inlet sand filtration) to 6.05 ± 0.03 mg/L (outlet sand filtration) after 120 min of treatment. These results indicate good water quality necessary for all forms of elemental life. Color and COD removals were 98.2 ± 0.2% and 39.02 ± 2.2%, respectively, during the electrocoagulation process (0.2915 mA/cm2 current density and 120 min of treatment). The proposed integrated process could be an attractive alternative of pretreatment of real wastewater to increase water quality of conventional treatments
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