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  • 1
    Language: English
    In: European journal of wildlife research, 2015, Vol.61(4), pp.617-621
    Description: Many wild populations of lizards in the Mediterranean Basin inhabit small islands frequently visited by humans. Reptiles respond to humans as potential predators by escaping to refuges or by increasing antipredator behaviours which lead to a loss of body condition and may have important consequences for fitness. We assessed effects of human pressure on parasitism and body condition of the endangered insular lizard Podarcis lilfordi in Aire Island (Balearic Islands, Spain). Two areas differing in the number of visitors were compared at different seasons: spring, with almost no human pressure, and summer, when the major bulk of visitors arrive. Compared across seasons, the lizards from areas frequented by humans suffered a greater loss of body condition and showed a less parasitism reduction compared to individuals from the undisturbed area. Therefore, human disturbance seems to have deleterious effects on body condition and other fitness-related drivers, as parasitism. Results evidence important consequences of tourism for short- and long-term fitness of individuals and should be considered when designing conservation plans or management strategies. ; p. 617-621.
    Keywords: Podarcis ; Antipredatory Behavior ; Body Condition ; Tourism ; Humans ; Spring ; Lizards ; Predators ; Parasitism ; Basins ; Summer ; Islands
    ISSN: 1612-4642
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  • 2
    Language: English
    In: Engineering Structures, 01 January 2016, Vol.106, pp.209-221
    Description: The use of advanced composites for building rehabilitation presents several advantages when compared with traditional construction materials. When degraded building floors need to be replaced, composite sandwich panels are a potentially interesting solution, namely for buildings with load-bearing rubble masonry walls. In this paper, connection systems between composite sandwich floors and load-bearing walls are proposed, and their behaviour under vertical loading is investigated. The systems comprise steel angles anchored to the walls, serving as main supports of the sandwich panels, which are then adhesively bonded and/or bolted to the angles. These connection systems are experimentally assessed using sandwich panels made of glass-fibre reinforced polymer (GFRP) face sheets and cores of either polyurethane (PUR) foam or balsa wood, by means of flexural tests on cantilevers, which are also simulated using non-linear finite element models. The structural response of the connection systems is determined, including the rotational stiffness conferred to the floors, the strength and the failure modes. Moment–rotation relationships are obtained for the connection systems and sandwich panel types considered, which provide a wide range of rotational stiffness values, from 60 to 10,856 kNm/rad per unit width (m). These are then used to analytically estimate the short-term mid-span deflections of floors with semi-rigid connections and spans ranging between 2 m and 5 m. It is shown that some of the proposed connections allow significant floor stiffness increases compared with simply supported conditions, with reductions in total mid-span deflection of up to 65% being achieved for a span of 4 m. The results obtained for the proposed connections highlight (i) their potential benefits for fulfilling serviceability limit states and (ii) the importance of considering an adequate structural model when designing sandwich floor panels.
    Keywords: Composites ; Sandwich Panels ; Floors ; Building Rehabilitation ; Connections ; Gfrp ; Polyurethane Foam ; Balsa Wood ; Engineering
    ISSN: 0141-0296
    E-ISSN: 1873-7323
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  • 3
    Language: English
    In: Composite Structures, 15 December 2015, Vol.134, pp.255-268
    Description: A connection system between adjacent sandwich panels for use in building floor rehabilitation, consisting of an adhesively (epoxy) bonded Z-joint, is proposed and studied. Experimental and numerical investigations were carried out to assess the joints’ behaviour under vertical loads, their effect on the overall mechanical response of the sandwich floor panels, and the stress distributions within the various panel components. Their behaviour along the transverse and longitudinal (main span) directions was studied for panels made of glass-fibre reinforced polymer (GFRP) faces and two types of cores: polyurethane (PUR) foam and balsa wood. The joints’ failure along the transverse direction occurred in the GFRP elements due to excessive through-thickness tensile stresses – failure in the adhesive layer was not observed. In the longitudinal direction, joint failure did not occur. The developed FE models were able to simulate the behaviour of the connections and jointed panels, providing reasonably accurate predictions for the deformations and failure modes experimentally observed. The joints significantly increased the panels’ shear stiffness, but showed limited influence on their bending stiffness. Although the flexural stiffness of the PUR foam and balsa wood cored panels was similar, the balsa wood core absorbed a significantly higher portion of shear force.
    Keywords: Sandwich Panels ; Connections ; Adhesive Joint ; Gfrp ; Polyurethane Foam ; Balsa Wood ; Engineering
    ISSN: 0263-8223
    E-ISSN: 1879-1085
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  • 4
    Language: English
    In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, 2016, Vol. 63(10), pp. 1737-1745
    Description: In this paper we propose a new representation for FFT algorithms called the triangular matrix representation. This representation is more general than the binary tree representation and, therefore, it introduces new FFT algorithms that were not discovered before. Furthermore, the new representation has the advantage that it is simple and easy to understand, as each FFT algorithm only consists of a triangular matrix. Besides, the new representation allows for obtaining the exact twiddle factor values in the FFT flow graph easily. This facilitates the design of FFT hardware architectures. As a result, the triangular matrix representation is an excellent alternative to represent FFT algorithms and it opens new possibilities in the exploration and understanding of the FFT.
    Keywords: Binary Tree; Cooley-Tukey; Fast Fourier Transform (Fft) ; Engineering And Technology ; Electrical Engineering, Electronic Engineering, Information Engineering ; Other Electrical Engineering, Electronic Engineering, Information Engineering ; Teknik Och Teknologier ; Elektroteknik Och Elektronik ; Annan Elektroteknik Och Elektronik
    ISSN: 1549-8328
    E-ISSN: 15580806
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  • 5
    Language: English
    In: IEEE Transactions on Circuits and Systems - II - Express Briefs, 2016, Vol. 63(9), pp. 868-872
    Description: This brief presents the feedforward short-time Fourier transform (STFT). This new approach is based on reusing the calculations of the STFT at consecutive time instants. This leads to significant savings in hardware components with respect to fast Fourier transform based STFTs. Furthermore, the feedforward STFT does not have the accumulative error of iterative STFT approaches. As a result, the proposed feedforward STFT presents an excellent tradeoff between hardware utilization and performance.
    Keywords: Feedforward; Fast Fourier Transform (Fft); Pipelined Architecture; Short-Time Fourier Transform (Stft) ; Engineering And Technology ; Electrical Engineering, Electronic Engineering, Information Engineering ; Other Electrical Engineering, Electronic Engineering, Information Engineering ; Teknik Och Teknologier ; Elektroteknik Och Elektronik ; Annan Elektroteknik Och Elektronik
    ISSN: 1549-7747
    E-ISSN: 15583791
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  • 6
    Language: English
    In: Composites Part B, 01 April 2016, Vol.90, pp.160-171
    Description: This paper presents an experimental and analytical study about the effect of temperature on the flexural creep of GFRP laminates produced by vacuum infusion. Such laminates are considered for use in the faces of sandwich panels for building floor application. Flexural creep tests were carried out in a three point bending configuration for stress levels of 15%, 25% and 35% of the laminate's flexural strength, and temperatures of 20 °C, 24 °C and 28 °C (a range likely to be found in the envisaged application), with durations between 1000 h and 2215 h. The creep response was observed to increase both with temperature and stress level. Findley's power law was used to model the experimental results, and extended to include an Arrhenius equation for temperature dependence of the creep response. The proposed model provided a good fit to the experimental creep curves, and was used to derive a set of practical design equations for the time-temperature dependent (i) flexural modulus, (ii) creep coefficient, and (iii) flexural modulus reduction factor. Finally, the time-temperature-stress superposition principle (TTSSP) and the time-stress superposition principle (TSSP) were used to obtain “master curves” that compared well with the proposed model's predictions.
    Keywords: A. Polymer-Matrix Composites (Pmcs) ; B. Creep ; C. Analytical Modelling ; E. Resin Transfer Moulding (Rtm) ; Temperature Effects ; Engineering
    ISSN: 1359-8368
    E-ISSN: 1879-1069
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  • 7
    Language: English
    In: Oecologia, August 2017, Vol.184(4), pp.859-871
    Description: Elucidating the factors determining reproductive success has challenged scientists since Darwin, but the exact pathways that shape the evolution of life history traits by connecting extrinsic (e.g., landscape structure) and intrinsic (e.g., female's age and endosymbionts) factors and reproductive success have rarely been studied. Here we collected female fleas from wild rodents in plots differing in their densities and proportions of the most dominant rodent species. We then combined path analysis and model selection approaches to explore the network of effects, ranging from micro to macroscales, determining the reproductive success of these fleas. Our results suggest that female reproductive success is directly and positively associated with their infection by Mycoplasma bacteria and their own body mass, and with the rodent species size and total density. In addition, we found evidence for indirect effects of rodent sex and rodent community diversity on female reproductive success. These results highlight the importance of exploring interrelated factors across organization scales while studying the reproductive success of wild organisms, and they have implications for the control of vector-borne diseases.
    Keywords: Fitness ; Life History ; Model Selection ; Parasites ; Path Analysis ; Scales ; Arthropod Vectors ; Flea Infestations ; Reproduction
    ISSN: 00298549
    E-ISSN: 1432-1939
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  • 8
    In: Molecular Ecology, September 2018, Vol.27(18), pp.3714-3726
    Description: The way that some parasites and pathogens persist in the hostile environment of their host for long periods remains to be resolved. Here, longitudinal field surveys were combined with laboratory experiments to investigate the routes of transmission and infection dynamics of such a pathogen—a wild rodent haemotropic bacterium, specifically a ‐like bacterium. Fleaborne transmission, direct rodent‐to‐rodent transmission and vertical transmission from fleas or rodents to their offspring were experimentally quantified, and indications were found that the main route of bacterial transmission is direct, although its rate of successful transmission is low (~20%). The bacterium's temporal dynamics was then compared in the field to that observed under a controlled infection experiment in field‐infected and laboratory‐infected rodents, and indications were found, under all conditions, that the bacterium reached its peak infection level after 25–45 days and then decreased to low bacterial loads, which persist for the rodent's lifetime. These findings suggest that the bacterium relies on persistency with low bacterial loads for long‐term coexistence with its rodent host, having both conceptual and applied implications.
    Keywords: Haemoplasmas ; Haemotropic Mycoplasmas ; Host–Parasite Interactions ; Infection Dynamics ; Persistent Infection ; Transmission Mechanisms ; Wild Rodent
    ISSN: 0962-1083
    E-ISSN: 1365-294X
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  • 9
    In: Ethology, February 2015, Vol.121(2), pp.116-124
    Description: Economic escape models predict escape decisions of prey which are approached by predators. Flight initiation distance (FID, predator–prey distance when prey begins to flee) and distance fled (DF) are major variables used to characterize escape responses. In optimal escape theory, FID increases as cost of not fleeing also increases. Moreover, FID decreases as cost of fleeing increases, due to lost opportunities to perform activities that may increase fitness. Finally, FID further increases as the prey's fitness increases. Some factors, including parasitism, may affect more than one of these predictors of FID. Initially, parasitized prey may have lower fitness as well as impaired locomotor ability, which would avoid predation and/or reduce their foraging ability, further decreasing the opportunity of fleeing. For example, if parasites decrease body condition, prey fitness is reduced and escape ability may be impaired. Hence, the overall influence of parasitism on FID is difficult to predict. We examined relationships between escape decisions and different traits: parasite load, body size and body condition in the Balearic lizard, . Lizards that showed higher haemogregarines load had longer FID and shorter DF. Although results did not confirm our initial predictions made on the basis of optimal escape theory, our findings suggest that parasites can alter several aspects of escape behaviour in a complex way.
    Keywords: Flight Initiation Distance ; Distance Fled ; Body Condition ; Parasitism ; Optimal Escape Theory
    ISSN: 0179-1613
    E-ISSN: 1439-0310
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  • 10
    Language: Spanish
    In: Revista Española de Orientación y Psicopedagogía, 2010, Vol.21(3), p.676
    ISSN: 1989-7448
    ISSN: 11397853
    Source: Fundación Dialnet
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