O sentido do risco

O risco é um tema central da cultura da modernidade. A cultura dominante na modernidade tem a pretensão de afirmar como universal a idéia de que o perigo deve ser enfrentado segundo os princípios do racionalismo individualista e utilitarista, que devem guiar o agente que assume a responsabilidade pelo risco. O risco adquire forma e relevância particulares para a fase juvenil na medida em que representa um processo de construção, experimentação e afirmação da própria identidade. Um processo cada vez mais fragmentado e ambíguo que, atualmente, realiza-se por meio de um alongamento da transição à vida adulta no âmbito de uma dinâmica geral de desinstitucionalização do curso da vida. Está em jogo aqui outro impulso típico da modernidade: o da reflexividade que, como sugere Giddens, é o desafio crucial da fase radical da modernidade. Podemos reconhecer nas ações dos jovens, em particular precisamente naquelas de tipo arriscado, a realização do imperativo de duvidar: por meio de seu agir, cancelam a suspensão da dúvida e realizam uma forma pragmática de reflexividade. A modernidade radical encontra-se diante de desafios. Tem, antes de tudo, a necessidade de identificar palcos para a construção e a experimentação pragmática de dinâmicas de confiança. Deve, além disso, mostrar-se capaz de consentir no aumento do poder decisório dos sujeitos, inscrevendo o emprego de tais poderes em vínculos sociais que, além de demonstrarem-se efetivamente eficazes e não ambivalentes, consigam, ao mesmo tempo, levar em conta tanto a dimensão emocional como as necessidades de confiabilidade relacional das pessoas envolvidas.The risk is a central theme of the culture in modernity. The dominant culture in modernity has the pretension of affirming as universal the idea that dangers should be faced according to the principles of individualistic rationalism and utilitarianism that should guide the agent that takes the responsibility for the risk. The risk assumes form and relevance for the juvenile phase in the measure as it represents a construction process, an experimentation and statement of one's own identity. A process more and more fragmented and ambiguous that takes place through a prolongation of the transition to the adult life in the extent of a general dynamics of de-institutionalisation of life. What is at play here is another typical demand of modernity: the one for reflexivity, as suggested by Giddens, it is the crucial challenge of the radical phase of modernity. We can recognize in the youths' actions, and precisely in those of a risky kind, the accomplishment of the imperative of doubting: through their acts, they suspend the suspension of the doubt, they accomplish a pragmatic form of reflexivity. The radical modernity produces a challenge. It has to be able to identify the proper stages for the construction and pragmatic experimentation of dynamics of confidence. It has to afford the empowerment of the agents, inscribing the use of such powers in social bonds that, besides being demonstrably effective and no ambivalent, do take into account as much the emotional dimension as the needs of the involved confidence in people's reliability

Camponotus fellah queens are singly mated

The ant Camponotus fellah has been used in several behavioral and life history studies. An important factor that affects the genetic structure and division of labour within a colony is whether queens are singly or multiply mated. To determine whether queens are singly mated in C. fellah, as is the case in some other Camponotus species, we developed nine polymorphic microsatellite markers and sequenced 16 workers each from 20 colonies at six loci. Data in all colonies were compatible with queen monoandry. All the workers of one of the colonies had identical genotypes suggesting that they were clonally produced or that the queen was inbred. We, therefore, genotyped the mother queen as well as 31 more workers of the same colony at the same six loci plus the three remaining loci. These data revealed that the queen was homozygous at eight of the nine loci and that she mated with a male having a shared allele at all but one of the loci. Thus, the queen was apparently not only inbred but also probably mated with a brother

O sentido do risco

O risco é um tema central da cultura da modernidade. A cultura dominante na modernidade tem a pretensão de afirmar como universal a idéia de que o perigo deve ser enfrentado segundo os princípios do racionalismo individualista e utilitarista, que devem guiar o agente que assume a responsabilidade pelo risco. O risco adquire forma e relevância particulares para a fase juvenil na medida em que representa um processo de construção, experimentação e afirmação da própria identidade. Um processo cada vez mais fragmentado e ambíguo que, atualmente, realiza-se por meio de um alongamento da transição à vida adulta no âmbito de uma dinâmica geral de desinstitucionalização do curso da vida. Está em jogo aqui outro impulso típico da modernidade: o da reflexividade que, como sugere Giddens, é o desafio crucial da fase radical da modernidade. Podemos reconhecer nas ações dos jovens, em particular precisamente naquelas de tipo arriscado, a realização do imperativo de duvidar: por meio de seu agir, cancelam a suspensão da dúvida e realizam uma forma pragmática de reflexividade. A modernidade radical encontra-se diante de desafios. Tem, antes de tudo, a necessidade de identificar palcos para a construção e a experimentação pragmática de dinâmicas de confiança. Deve, além disso, mostrar-se capaz de consentir no aumento do poder decisório dos sujeitos, inscrevendo o emprego de tais poderes em vínculos sociais que, além de demonstrarem-se efetivamente eficazes e não ambivalentes, consigam, ao mesmo tempo, levar em conta tanto a dimensão emocional como as necessidades de confiabilidade relacional das pessoas envolvidas.The risk is a central theme of the culture in modernity. The dominant culture in modernity has the pretension of affirming as universal the idea that dangers should be faced according to the principles of individualistic rationalism and utilitarianism that should guide the agent that takes the responsibility for the risk. The risk assumes form and relevance for the juvenile phase in the measure as it represents a construction process, an experimentation and statement of one's own identity. A process more and more fragmented and ambiguous that takes place through a prolongation of the transition to the adult life in the extent of a general dynamics of de-institutionalisation of life. What is at play here is another typical demand of modernity: the one for reflexivity, as suggested by Giddens, it is the crucial challenge of the radical phase of modernity. We can recognize in the youths' actions, and precisely in those of a risky kind, the accomplishment of the imperative of doubting: through their acts, they suspend the suspension of the doubt, they accomplish a pragmatic form of reflexivity. The radical modernity produces a challenge. It has to be able to identify the proper stages for the construction and pragmatic experimentation of dynamics of confidence. It has to afford the empowerment of the agents, inscribing the use of such powers in social bonds that, besides being demonstrably effective and no ambivalent, do take into account as much the emotional dimension as the needs of the involved confidence in people's reliability

Le origini estetiche del giardino e le quinte selvagge della natura

The essay, refuting a widely accepted position in the history of the economy, and starting from an unprecedented assumption, intends to demonstrate that the gardens were not built for utilitarian reasons, but, by observing the human cultural evolutionary development on earth, for que-stions of aesthetic, giving autonomy to human thought, freeing it from economic logic, and thus linking the characteristics of evolution with those of aesthetics, furthermore proposing the theory of the wild scenes of natu-re as a place/experience through which to obtain knowledge not yet explo-red by intellect, for a more biological reading of cultural development

Experimental investigation on tensile and shear bond behaviour of Basalt-FRCM composites for strengthening calcarenite masonry elements

The use of Fabric Reinforced Cementitious Matrix (FRCM) composites for structural retrofit has seen an increased interest among the scientific community, during the last decade. Various studies have revealed their effectiveness as external retrofitting technique of masonry elements, offering numerous advantages respect to the well know Fibre Reinforced Polymer (FRP) in terms of compatibility with masonry support, reversibility of intervention and sustainability. Despite the growing use, the characterization of FRCM mechanical behaviour is still an open issue, due to numerous uncertainties involved in test set-up adopted and fibre-mortar combination. The proposed experimental study aims to investigate the tensile and shear bond behaviour of Basalt-FRCM for strengthening calcarenite masonry elements. Calcarenite is a natural stone with sedimentary origin and it is widely present in existing buildings of the Mediterranean areas. Direct tensile tests are performed on two types of Basalt-FRCM coupons, with cement-based and lime-based mortar, adopting two different test-set-up based on clamping and clevis grip methods. Moreover, double shear bond tests are carried out to evaluate the adhesion properties of the two types of Basalt-FRCM with calcarenite support. Experimental outcomes are compared in terms of stress-strain curves, evaluating the influence of mortar grade and test set-up on the mechanical performances of Basalt-FRCM composites. The comparisons provide information about the mechanical stress transfer phenomena that occur at the fibre-to-matrix and FRCM-to-substrate interface level and the failure modes

Innovative connections for steel-concrete-trussed beams: a patented solution

The most recent design strategies welcome the adoption of innovative techniques for seismic energy input mitigation, aiming to achieve high dissipation capacity, prevent the structure from collapse and ensure the serviceability of the construction. Friction damper devices have been widely adopted in framed steel structures for decades, while their introduction in different structural types is still under investigation. This paper presents the outcomes of innovative research supported by the industry and conducted on beam-to-column connections of RC structures in which the beams are Hybrid Steel-Trussed Concrete Beams (HSTCBs) and the columns are classical RC pillars. An innovative solution, recently patented, has been found for the mitigation of the effects of seismic cyclic actions on small-sized beam-column joints, typically characterised by a large amount of longitudinal reinforcement due to the small effective depth of the beam. This paper collects the main featuring steps of the innovative research, which has led to the patented solution. The calculation procedure for designing the proposed connection is shown, and the validation through 3D finite element modelling is described. For the structural analysis of the joint, several monotonic and cyclic simulations have been carried out with the scope of investigating different design moment values. The finite element results proved that the patented solution is effective in preventing beam, column and joint from damage and it is suitable for exhibiting adequate dissipative capacity ensured by a flexural behaviour dominated by wide and stable hysteresis loops

Innovative connections for steel-concrete-trussed beams: a patented solution

The most recent design strategies welcome the adoption of innovative techniques for seismic energy input mitigation, aiming to achieve high dissipation capacity, prevent the structure from collapse and ensure the serviceability of the construction. Friction damper devices have been widely adopted in framed steel structures for decades, while their introduction in different structural types is still under investigation. This paper presents the outcomes of innovative research supported by the industry and conducted on beam-to-column connections of RC structures in which the beams are Hybrid Steel-Trussed Concrete Beams (HSTCBs) and the columns are classical RC pillars. An innovative solution, recently patented, has been found for the mitigation of the effects of seismic cyclic actions on small-sized beam-column joints, typically characterised by a large amount of longitudinal reinforcement due to the small effective depth of the beam. This paper collects the main featuring steps of the innovative research, which has led to the patented solution. The calculation procedure for designing the proposed connection is shown, and the validation through 3D finite element modelling is described. For the structural analysis of the joint, several monotonic and cyclic simulations have been carried out with the scope of investigating different design moment values. The finite element results proved that the patented solution is effective in preventing beam, column and joint from damage and it is suitable for exhibiting adequate dissipative capacity ensured by a flexural behaviour dominated by wide and stable hysteresis loops

Experimental characterization of friction properties of materials for innovative beam-to-column dissipative connection for low-damage RC structures

Low-damage design of structures in seismic-prone areas is becoming an efficient strategy to obtain "earthquake-proof" buildings, i.e. buildings that, even in the case of severe seismic actions, experience a low or negligible amount of damage. Besides the safeguard of human lives, this design strategy aims also to limit the downtime of buildings, which represents a significant source of economic loss, and to ensure an immediate occupancy in the aftermath of an earthquake. In this context, focusing on moment-resisting frames (MRFs), several solutions have been developed for the beam-to-column connections (BCCs) of steel and precast/prestressed concrete structures, but very few for cast-in-situ reinforced concrete (RC) structures. This paper focuses on a recently-proposed friction-based BCC for MRFs made with hybrid steel-trussed concrete beams (HSTCBs). The latter are made by a spatial lattice built using V-shaped rebars and a steel bottom plate, which eases the introduction of a friction dissipative device. HSTCBs are usually characterized by a small effective depth, which leads to a large amount of longitudinal rebars. The latter, together with a small-sized beam-column joint, make it potentially subjected to severe damage, which reduces its dissipative capacity. The shear force acting on the joint can be reduced by endowing the BCC with a friction device, with the aim of increasing the lever arm of the bending moment transferred between beam and joint, preventing the latter from damage. To evaluate the mechanical performance of the above connection, two experimental programs have been carried out at the Structures Laboratory of the University of Palermo. The first one focused on the characterization of the friction properties of two different materials (thermal sprayed aluminum and brass), by means of a linear dissipative device subjected to cyclic load. The second one tested a beam-to-column subassembly endowed with the recently-proposed connection in which the dissipative device was made with the best performing friction material tested before. The results of the cyclic tests are presented and commented, showing the promising performance of such connection in providing a low-damage behavior and a satisfactory dissipative capacity

Seismic Performance of Earthquake-Resilient RC Frames Made with HSTC Beams and Friction Damper Devices

Seismic behavior of RC frames with hybrid steel-trussed concrete beams is affected by panel zone damage due to a large amount of longitudinal reinforcement. Here the seismic efficiency of innovative frames characterized by friction damper devices (FDDs) at beam-to-column connections is compared against traditional frame. Three configurations are investigated: FDDs alone; FDDs with column-to-foundation connections having preloaded threaded bars and disk springs; FDDs with self-centering friction devices. Non-linear analyses show that FDDs alone prevent plastic hinge formation at beam ends and beam–column joint damage. FDDs with self-centering friction devices effectively limit both peak and residual drifts, avoiding column base plasticization

Low-Damage Friction Connections in Hybrid Joints of Frames of Reinforced-Concrete Buildings

Seismic-resilient buildings are increasingly designed following low-damage and free-from-damage design strategies that aim to protect the structure’s primary load-bearing systems under ultimate-level seismic loads. With this scope, damping devices are located in accessible and easy-to-inspect sites within the main structural frames where the damage concentrates, allowing the primary structure to remain mostly undamaged or easily repairable after a severe earthquake. This paper analyses the effects of friction-damping devices in structural joints of RC buildings endowed with hybrid steel-trussed concrete beams (HSTCBs) and standard RC columns. The study proposes innovative solutions to be adopted into RC moment-resisting frames (MRFs) at beam-to-column connections (BCCs) and column-base connections (CBCs). The cyclic behaviour of the joint is analysed through 3D finite element models, while pushover and non-linear time history analyses are performed on simple two-storey and two-span MRFs endowed with the proposed devices. The main results show that the BCC endowed with curved slotted holes and Perfobond connectors is the most effective in preventing the damage that might occur in beam, column, and joint, and it is adequate to guarantee good dissipative properties. For CBCs, the results showed that the re-centering system with friction pads is the most effective in containing the peak and residual drifts, preventing the plasticization of the column base