165 research outputs found

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    Seismic Design and Preliminary Analyses of a Prefabricated Hybrid Steel-Concrete Wall

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    Steel frames with reinforced concrete infill walls (SRCWs) are an interesting structural solution for applications in seismic areas if designed to exploit the stiffness of reinforced concrete (RC) and the ductility and dissipative capacity of steel. Three horizontal resisting mechanisms can be identified in SRCW: 1) contribution of the steel frame; 2) direct interactions between the steel frame and the compression strut in the RC infill walls; 3) interactions between steel frame and the RC infill wall through friction and shear connectors. While Eurocode 8 considers SRCWs to behave essentially as RC walls, numerical analyses demonstrated that this assumption may be far from reality. Innovative solutions for SRCW and relevant design approaches were eventually proposed in order to achieve a structural system able to fully exploit the advantages of the steel and RC components. In this context, the present study investigates a type of innovative modular SRCW through numerical simulations allowing a better understanding of its structural behaviour

    Please, sir, pull down your socks!

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    A 48-year-old male patient presented at the regular followupvisit seven months after a successful kidney transplant.After discussion of blood chemistries with the doctor, thepatient underwent a physical examination. As usual, heunbuttoned his shirt and undid his trouser belt. Inspectionof the limbs, after pulling up his trousers, confirmed thepresence of ankle oedema; the graft was quite firm, with nomurmurs in the area

    Vertebrae reveal industrial-era increases in Atlantic bluefin tuna catch-at-size and juvenile growth

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    Climate change and size-selective overexploitation can alter fish size and growth, yet our understanding of how and to what extent is limited due to a lack of long-term biological data from wild populations. This precludes our ability to effectively forecast population dynamics and support sustainable fisheries management. Using modern, archived, and archaeological vertebrae dimensions and growth rings of one of the most intensely exploited populations, the eastern Atlantic and Mediterranean bluefin tuna (Thunnus thynnus, BFT), we estimated catch-at-size and early-life growth patterns from the 3 (rd) century bce to the 21 (st) century ce to understand responses to changes in its environment. We provide novel evidence that BFT juvenile growth increased between the 16 (th)-18 (th), 20 (th), and 21 (st) centuries, and is correlated with a warming climate and likely a decrease in stock biomass. We found it equally plausible that fisheries-induced evolution has acted to increase juvenile BFT growth, driving earlier maturation as a result of size-selective exploitation. Coincidently, we found limited evidence to suggest a long history of large ( >200 cm FL) BFT capture. Instead, we found that the catch-at-size of archaeological BFT was relatively small in comparison with more intensive, 20 (th) and 21 (st) century tuna trap fisheries which operated further from shore. This complex issue would benefit from studies using fine-scale biochronological analyses of otoliths and adaptation genomics, throughout the last century especially, to determine evolutionary responses to exploitation, and further disentangle the influence of temperature and biomass on fish growth

    Characterization of dry-stack interlocking compressed earth blocks

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    Earth has been a traditional building material to construct houses in Africa. One of the most common techniques is the use of sun dried or kiln fired adobe bricks with mud mortar. Fired bricks are the main cause for deforestation in countries like Malawi. Although this technique is low-cost, the bricks vary largely in shape, strength and durability. This leads to weak houses which suffer considerable damage during floods and seismic events. One solution is the use of dry-stack masonry with stabilized interlocking compressed earth blocks (ICEB). This technology has the potential of substituting the current bricks by a more sustainable kind of block. This study was made in the context of the HiLoTec project, which focuses on houses in rural areas of developing countries. For this study, Malawi was chosen for a case study. This paper presents the experimental results of tests made with dry-stack ICEBs. Soil samples from Malawi were taken and studied. Since the experimental campaign could not be carried out in Malawi, a homogenization process of Portuguese soil was made to produce ICEBs at the University of Minho, Portugal. Then, the compression and tensile strength of the materials was determined via small cylinder samples. Subsequently, the compression and flexural strength of units were determined. Finally, tests to determine the compressive strength of both prisms and masonry wallets and to determine the initial shear strength of the dry interfaces were carried out. This work provides valuable data for low-cost eco-efficient housingThis work was carried out under the research project HiLoTec - Development of a Sustainable Self-Construction System for Developing Countries. The authors wish to thank Mota-Engil Constructing Group for supporting this project

    Effect of different weaning age (21, 28 or 35 days) on production, growth and certain parameters of the digestive tract in rabbits

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    The effect of different weaning ages, that is, 21 (G21), 28 (G28) or 35 (G35) days, on growth and certain parameters of the digestive tract was examined in rabbits to assess the risk of early weaning attributable to the less-developed digestive system. On days 35 and 42, G35 rabbits had 10% to 14% and 10% higher BW, respectively ( P,0.05), than those weaned at days 21 and 28. In the 4th week of life, early weaned animals had 75% higher feed intake than G28 and G35 rabbits ( P,0.05). The relative weight of the liver increased by 62% between 21 and 28 days of age, and thereafter it decreased by 76% between 35 and 42 days of age ( P,0.05), with G21 rabbits having 29% higher weight compared with G35 animals on day 35 ( P,0.05). The relative weight of the whole gastrointestinal (GI) tract increased by 49% and 22% after weaning in G21 and G28 rabbits, respectively ( P,0.05). On day 28, the relative weight of the GI tract was 19% higher in G21 than in G28 rabbits, whereas on day 35 G21 and G28 animals had a 12% heavier GI tract compared with G35 rabbits ( P,0.05). Age influenced the ratio of stomach, small intestine and caecum within the GI tract; however, no effect of different weaning age was demonstrated. The pH value of the stomach and caecum decreased from 5.7 to 1.6 and from 7.1 to 6.3, respectively, whereas that of the small intestine increased from 6.8 to 8.4 ( P,0.05); the differences between groups were not statistically significant. Strictly anaerobic culturable bacteria were present in the caecum in high amounts (108), already at 14 days of age; no significant difference attributable to weaning age was demonstrable. The concentration of total volatile fatty acids (tVFA) was higher in G21 than in G28 and G35 throughout the experimental period ( P,0.05). The proportion of acetic and butyric acid within tVFA increased, whereas that of propionic acid decreased, resulting in a C3 : C4 ratio decreasing with age. Early weaning (G21) resulted in higher butyric acid and lower propionic acid proportions on day 28 ( P,0.05). No interaction between age and treatment was found, except in relative weight of the GI tract and caecal content. In conclusion, early weaning did not cause considerable changes in the digestive physiological parameters measured, but it resulted in 10% lower growth in rabbits

    Puzzling over spurdogs : molecular taxonomy assessment of the Squalus species in the Strait of Sicily

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    The actual occurrence of Squalus megalops in the Mediterranean Sea has recently been questioned. Several research works which sought to assess available morphological and meristic features that differentiate S. megalops from other Squalus species in the Mediterranean Sea, revealed poor discriminatory power and high variability of the assessed characters, especially when comparing S. megalops and S. blainville. The application of molecular tools does not support the presence of S. megalops. In the present study, we screened spurdog species from the Strait of Sicily using a molecular taxonomy approach based on two mitochondrial DNA markers and we report the occurrence of two Squalus lineages characterizing specimens collected from the stretch of sea between Tunisia, southern Sicily, Malta and Libya. The results support the hypothesis that a common species, S. blainville, currently inhabits the Mediterranean Sea, while a second and rare species is probably an occasional visitor with high morphological similarity to the S. megalops and S. blainville but is genetically distinct from both. Within this perspective, the occurrence of S. megalops in the Mediterranean Sea is not confirmed and our study highlights the taxonomic uncertainties in relation to the occurrence and distribution of Squalus species in this region. We encourage the establishment of a coordinated international effort to implement a comprehensive and integrated taxonomic assessment on this genus which represents an irreplaceable component of the biodiversity of the area.peer-reviewe

    Eurocity London: a qualitative comparison of graduate migration from Germany, Italy and Latvia

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    This paper compares the motivations and characteristics of the recent migration to London of young-adult graduates from Germany, Italy and Latvia. Conceptually the paper links three domains: the theory of core–periphery structures within Europe; the notion of London as both a global city and a ‘Eurocity’; and the trope of ‘crisis’. The dataset analysed consists of 95 in-depth biographical interviews and the paper’s main objective is to tease out the narrative similarities and differences between the three groups interviewed. Each of the three nationalities represents a different geo-economic positioning within Europe. German graduates move from one economically prosperous country to another; they traverse shallow economic and cultural boundaries. Italian graduates migrate from a relatively peripheral Southern European country where, especially in Southern Italy, employment and career prospects have long been difficult, and have become more so in the wake of the financial crisis. They find employment opportunities in London which are unavailable to them in Italy. Latvian graduates are from a different European periphery, the Eastern one, post-socialist and post-Soviet. Like the Italians, their moves are economically driven whereas, for the Germans, migration is more related to lifestyle and life-stage. For all three groups, the chance to live in a large, multicultural, cosmopolitan city is a great attraction. And for all groups, thoughts about the future are marked by uncertainty and ambiguity

    Intra-European Movement: Multi-Level or Mismatched Governance?

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    The case of intra-EU mobility raises significant debate about multi-level governance (MLG) both in analytical terms – how multi-level is governance of intra-EU mobility, what actors are involved and how? – and normative terms – can intra-EU mobility be seen as ‘successful’ multi-level governance? Intra-EU mobility is an area that faces both issue complexity and institutional complexity (Stephenson, 2013, pp. 817) and as such, the governance arrangements are often correspondingly complex. This chapter will attempt to locate the case of intra-EU mobility within the broader literature on multi-level governance and try to draw out lessons for understanding MLG as a practical, analytical and normative concept. This is relevant to both the understanding of intra-EU mobility and the understanding of MLG. On the one hand, additional cases help to support or refute the robustness of our conceptualisation of multi-level governance; on the other hand, MLG as a concept can help us to understand the entanglement of a complex issue that cuts across political and policy bounds. The chapter will first develop a framework of multi-level governance that can be applied to intra-EU migration. Then, the structural, relational and policy factors that affect MLG will be explored in the context of this specific case. The final section will try to craft some answers about what intra-EU migration policy can tell us about multi-level governance, and vice versa
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