Modal parameters identification with environmental tests and advanced numerical analyses for masonry bell towers: a meaningful case study

Abstract In the first part, a dynamic monitoring for non-destructive evaluation of heritage structures is discussed with reference to a case study, namely the Pomposa Abbey belfry, located in the Ferrara Province (Italy). The main dynamic parameters constitute an important reference to define an advanced numerical model, discussed in the second part, based on Non-Smooth Contact Dynamics (NSCD) method. Schematised as a system of rigid blocks undergoing frictional sliding and plastic impacts, the tower has exhibited complex dynamics, because of both geometrical nonlinearity and the non-smooth nature of the contact laws. First, harmonic oscillations have been applied to the basement of the tower and a systematic parametric study has been conducted, aimed at correlating the system vulnerability to the values of amplitude and frequency of the assigned excitation corroborated by the dynamic identification results. In addition, numerical analyses have been done to highlight the effects of the friction coefficient and of the blocks geometries on the dynamics, in particular on the collapse modes. Finally, a study of the tower stability against seismic excitations has been addressed and 3D simulations have been performed with a real earthquake

iconic crumbling of the clock tower in amatrice after 2016 central italy seismic sequence advanced numerical insight

Abstract The present paper investigates from an advanced numerical point of view the progressive damage of the Amatrice (Rieti, Italy) civic clock tower, after a long sequence of strong earthquakes that struck central Italy in 2016. Two advanced numerical models are here utilised to have an insight into the modalities of progressive damage and the behaviour of the structure under strong non-linear dynamic excitations, namely a Non-Smooth Contact Dynamics (NSCD) and a FE Concrete Damage Plasticity (CDP) models. In both cases, a full 3D detailed discretization is adopted. From the numerical results, both the role played by the actual geometries and the insufficient resistance of the constituent materials are envisaged, showing a good match with actual crack patterns observed after the seismic sequence

Optimum sample size to estimate mean parasite abundance in fi sh parasite surveys

[EN] To reach ethically and scientifically valid mean abundance values in parasitological and epidemiological studies this paper considers analytic and simulation approaches for sample size determination. The sample size estimation was carried out by applying mathematical formula with predetermined precision level and parameter of the negative binomial distribution estimated from the empirical data. A simulation approach to optimum sample size determination aimed at the estimation of true value of the mean abundance and its confidence interval (CI) was based on the Bag of Little Bootstraps (BLB). The abundance of two species of monogenean parasites Ligophorus cephali and L. mediterraneus from Mugil cephalus across the Azov-Black Seas localities were subjected to the analysis. The dispersion pattern of both helminth species could be characterized as a highly aggregated distribution with the variance being substantially larger than the mean abundance. The holistic approach applied here offers a wide range of appropriate methods in searching for the optimum sample size and the understanding about the expected precision level of the mean. Given the superior performance of the BLB relative to formulae with its few assumptions, the bootstrap procedure is the preferred method. Two important assessments were performed in the present study: i) based on CIs width a reasonable precision level for the mean abundance in parasitological surveys of Ligophorus spp. could be chosen between 0.8 and 0.5 with 1.6 and 1x mean of the CIs width, and ii) the sample size equal 80 or more host individuals allows accurate and precise estimation of mean abundance. Meanwhile for the host sample size in range between 25 and 40 individuals, the median estimates showed minimal bias but the sampling distribution skewed to the low values; a sample size of 10 host individuals yielded to unreliable estimates.SS and VS were supported by MEDEA project fellowships, Erasmus Mundus Action 2. CC-S was funded by project #MTM2014-52975-C2-1-R:" Inference in Structured Additive Regression (STAR) Models with Extensions to Multivariate Responses. Applications in Biomedicine", cofinanced by the Ministry of Economy and Competitiveness (SPAIN) and by the European Regional Development Fund (FEDER). This study is partially supported by Ministry of Education and Science of Ukraine, project #1/17.Shvydka, S.; Sarabeev, V.; Estruch, VD.; Cadarso-Suarez, C. (2018). Optimum sample size to estimate mean parasite abundance in fi sh parasite surveys. Helminthologia. 55(1):52-59. https://doi.org/10.1515/helm-2017-0054S5259551Rohde, K., Hayward, C., & Heap, M. (1995). Aspects of the ecology of metazoan ectoparasites of marine fishes. International Journal for Parasitology, 25(8), 945-970. doi:10.1016/0020-7519(95)00015-tAnderson, R. M., & Gordon, D. M. (1982). Processes influencing the distribution of parasite numbers within host populations with special emphasis on parasite-induced host mortalities. Parasitology, 85(2), 373-398. doi:10.1017/s0031182000055347Poiani, A. (1992). Ectoparasitism as a possible cost of social life: a comparative analysis using Australian passerines (Passeriformes). Oecologia, 92(3), 429-441. doi:10.1007/bf00317470Kleiner, A., Talwalkar, A., Sarkar, P., & Jordan, M. I. (2014). A scalable bootstrap for massive data. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 76(4), 795-816. doi:10.1111/rssb.12050Jovani, R., & Tella, J. L. (2006). Parasite prevalence and sample size: misconceptions and solutions. Trends in Parasitology, 22(5), 214-218. doi:10.1016/j.pt.2006.02.011BAGGE, A. M., SASAL, P., VALTONEN, E. T., & KARVONEN, A. (2005). Infracommunity level aggregation in the monogenean communities of crucian carp (Carassius carassius). Parasitology, 131(3), 367-372. doi:10.1017/s0031182005007626Belghyti, D., Berrada-rkhami, O., Boy, V., Aguesse, P., & Gabrion, C. (1994). Population biology of two helminth parasites of flatfishes from the Atlantic coast of Morocco. Journal of Fish Biology, 44(6), 1005-1021. doi:10.1111/j.1095-8649.1994.tb01272.xTAYLOR, L. R. (1961). Aggregation, Variance and the Mean. Nature, 189(4766), 732-735. doi:10.1038/189732a

Processamento e produtos.

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Cloacal Bacterial Diversity Increases with Multiple Mates: Evidence of Sexual Transmission in Female Common Lizards

Sexually transmitted diseases have often been suggested as a potential cost of multiple mating and as playing a major role in the evolution of mating systems. Yet there is little empirical data relating mating strategies to sexually transmitted microorganisms in wild populations. We investigated whether mating behaviour influences the diversity and composition of cloacal assemblages by comparing bacterial communities in the cloaca of monandrous and polyandrous female common lizards Zootoca vivipara sampled after the mating period. We found that polyandrous females harboured more diverse communities and differed more in community composition than did monandrous females. Furthermore, cloacal diversity and variability were found to decrease with age in polyandrous females. Our results suggest that the higher bacterial diversity found in polyandrous females is due to the sexual transmission of bacteria by multiple mates. The impact of mating behaviour on the cloacal microbiota may have fitness consequences for females and may comprise a selective pressure shaping the evolution of mating systems

Evaluation of potential habitat with an integrated analysis of a spatial conservation strategy for David’s deer, Elaphurus davidians

How to assess the potential habitat integrating landscape dynamics and population research, and how to reintroduce animals to potential habitats in environments highly human disturbed are still questions to be answered in conservation biology. According to behavioral research on Elaphurus davidians, we have developed a suitability index and a risk index to evaluate the potential habitats for the deer. With these indices, we conducted two transect assessments to evaluate the gradient change of the target region. Then, taking rivers as border lines, we tabulated the forest areas, high grassland area and total area and then compared the forest and high grassland area in each subregion. Furthermore, we computed the land use transfer matrix for the whole Yancheng coast during 1987–2000. We also computed human modified index (HMI) in six subregions. Lastly with a geographical information system support we obtained the spatial distribution of the indices and evaluation of the whole potential habitats from a neighborhood analysis. The transect assessment showed that the suitability of the coastal area was higher than that of the inland area for the deer, while the southern area was higher than the northern. Landscape metrics and HMI analysis showed that different landscape patterns and different anthropogenic disturbance existed within the region, and the increasing human disturbance was the key factor causing the pattern dynamics. The evaluation of potential habitats showed that there was an estimated carrying capacity of no more than 10,000 for David’s deer reintroduction into the natural area. Also the reintroduction strategy was discussed. This integrated approach linked the population research and the landscape metrics, and the dataset with different scale; thus, it is an approach likely to be useful for the protection of other large animal in a landscape highly disturbed by humans