287 research outputs found
Nematode Communities in Soils of the Same Volcanic Origin across a Gradient of Naturalization: From Intensive Agriculture to Forest
No full textNematodes play a key role in ecological environments. Biotic indices based on soil nematode community are effectively used for assessing soil health status. This work represents the opportunity to investigate three different management practices continuously maintained for 40 or more decades on soils with the same geological origin. This unique feature allows us to reduce variables and link biotic with abiotic factors. Therefore, the nematode communities of three neighboring volcanic soils under different managements were examined. The maximum values in soil biodiversity were found in the forest environment in which all the trophic groups were detected and well balanced. Instead, in permanent grassing and carnation crop greenhouse (CG), biodiversity indices progressively decreased with the intensification of agricultural practices. Furthermore, CG showed a stronger dominance of a specific plant-parasitic nematode identified as Heterodera daverti. Nematode indicators demonstrated that changes in the nematode community gradually varied from anthropic to natural environments whereas soil properties were feebly correlated to nematode community indicators. In conclusion, we demonstrated that biodiversity and ecological indices applied to the soil nematode community are effective at detecting alterations due to anthropogenic impact. Nematodes seem to be susceptible to perceiving the soil dynamics
Stochastic identification of masonry parameters in 2D finite elements continuum models
No full textThe comprehension and structural modeling of masonry constructions is fundamental to safeguard the integrity of built cultural assets and intervene through adequate actions, especially in earthquake-prone regions. Despite the availability of several modeling strategies and modern computing power, modeling masonry remains a great challenge because of still demanding computational efforts, constraints in performing destructive or semidestructive in-situ tests, and material uncertainties. This paper investigates the shear behavior of masonry walls by applying a plane-stress FE continuum model with the Modified Masonry-like Material (MMLM). Epistemic uncertainty affecting input parameters of the MMLM is considered in a probabilistic framework. After appointing a suitable probability density function to input quantities according to prior engineering knowledge, uncertainties are propagated to outputs relying on gPCE-based surrogate models to considerably speed up the forward problemsolving. The sensitivity of the response to input parameters is evaluated through the computation of Sobol’ indices pointing out the parameters more worthy to be further investigated, when dealing with the seismic assessment of masonry buildings. Finally, masonry mechanical properties are calibrated in a probabilistic setting with the Bayesian approach to the inverse problem based on the available measurements obtained from the experimental loaddisplacement curves provided by shear compression in-situ tests
Indigenous peoples and climate justice. A critical analysis of international human rights law and governance
No full textThis book provides a new interpretation of international law specifically dedicated to Indigenous peoples in the context of a climate justice approach. The book presents a critical analysis of past and current developments at the intersection of human rights and international environmental law and governance. The book suggests new ways forward and demonstrates the need for a paradigmatic shift that would enhance the meaningful participation of Indigenous peoples as fundamental actors in the conservation of biodiversity and in the fight against climate change. The book offers guidance on a number of critical intersecting and interdependent issues at the forefront of climate change law and policy – inside and outside of the UN climate change regime. The author suggests that the adoption of a critical perspective on international law is needed in order to highlight inherent structural and systemic issues of the international law regime which are all issues that ultimately impede the pursue of climate justice for Indigenous peoples.
Giada Giacomini is an experienced researcher in international human rights law, international environmental law, climate change law and policy, and with an interest in climate vulnerable communities. She holds a PhD in Public, Comparative and International Law. She specializes in climate justice, critical legal studies and non-anthropocentric law. Upon completion of her PhD studies, she completed an Internship at the Independent Redress Mechanism of the Green Climate Fund. She is currently involved in several research projects dealing with ecosocial work, environmental conservation and Indigenous peoples, and climate litigation
Modulating factors of individual sensitivity to diepoxybutane: sister chromatid exchanges induced in vitro in human lymphocytes
No full textSpontaneous and diepoxybutane (DEB)-induced sister chromatid exchanges (SCEs) were examined in cultured peripheral lymphocytes (PBL) from 122 healthy donors. SCE-inducing activity under defined experimental conditions and individual sensitivity to genotoxic stress were assessed. SCE means distribution appeared asymmetrical, identifying about 22% of subjects characterized by a 'high-respondent' phenotype with more than 111 SCEs/cell. Confounding factors, such as smoking habit, wine and coffee consumption, work activity and hematological factors, showed a limited capacity to affect individual SCE responsiveness, however hemoglobin and uric acid seemed to antagonize DEB genotoxicity
Service Shifting: a Paradigm for Service Resilience in 5G
No full textMany real-world services can be provided through multiple virtual network function (VNF) graphs, corresponding, e.g., to high- and low-complexity variants of the service itself. Based on this observation, we extend the concept of service scaling in network orchestration to service shifting, i.e., upgrading or downgrading the VNF graph to use among those implementing the same service. Service shifting can serve multiple goals, from reducing operational costs to reacting to infrastructure problems. Furthermore, it enhances the flexibility of service-level agreements between network operators and third party content providers (“verticals”). In this paper, we introduce and describe the service shifting concept, its benefits, and the associated challenges, with special reference to how service shifting can be integrated within real-world 5G architectures and implementations. We conclude that existing network orchestration frameworks can be easily extended to support service shifting, and its adoption has the potential to make 5G network slices easier for the operators to manage under high-load conditions, while still meeting the verticals’ requirements
Peak velocities estimation for a direct five-step design procedure of inter-storey viscous dampers
No full textIn the last decades, the use of added viscous dampers for the mitigation of the
effects due to the seismic action upon the structural elements has been worldwide spread.
In this respect, several design methods aimed at sizing the viscous dampers to be inserted
in building structures have been proposed. Among others, some of the authors proposed a
five-step procedure which guides the practical design from the choice of a target reduction
in the seismic response of the structural system (with respect to the response of a structure
without any additional damping device), to the identification of the corresponding damping
ratio and the mechanical characteristics (i.e. the damping coefficient values for chosen
damping exponent, the oil stiffnes, the maximum damper forces) of the commercially
available viscous dampers. The procedure requires the development of numerical simulations
for the evaluation of the peak inter-storey velocity profiles, necessary for the
evaluation of the damper forces. In the present paper a comprehensive study on the interstorey
velocity profiles developed in shear-type building structures under seismic excitation
is conducted with the purpose of deriving analytical formulae for their estimation. The
analytical estimations of the peak inter-storey velocities are then used to simplify the
original five-step procedure leading to a direct (i.e. fully analytical) procedure. The direct
procedure is suitable for the preliminary design of the added viscous dampers, in particular
for practitioners not dealing everyday with the design of added viscous dampers.In the last decades, the use of added viscous dampers for the mitigation of the effects due to the seismic action upon the structural elements has been worldwide spread. In this respect, several design methods aimed at sizing the viscous dampers to be inserted in building structures have been proposed. Among others, some of the authors proposed a five-step procedure which guides the practical design from the choice of a target reduction in the seismic response of the structural system (with respect to the response of a structure without any additional damping device), to the identification of the corresponding damping ratio and the mechanical characteristics (i.e. the damping coefficient values for chosen damping exponent, the oil stiffnes, the maximum damper forces) of the commercially available viscous dampers. The procedure requires the development of numerical simulations for the evaluation of the peak inter-storey velocity profiles, necessary for the evaluation of the damper forces. In the present paper a comprehensive study on the inter-storey velocity profiles developed in shear-type building structures under seismic excitation is conducted with the purpose of deriving analytical formulae for their estimation. The analytical estimations of the peak inter-storey velocities are then used to simplify the original five-step procedure leading to a direct (i.e. fully analytical) procedure. The direct procedure is suitable for the preliminary design of the added viscous dampers, in particular for practitioners not dealing everyday with the design of added viscous dampers
A “direct five-step procedure” for the preliminary seismic design of buildings with added viscous dampers
No full textIn the present work a direct procedure for the preliminary seismic design of building structures with added dampers is described which represents the simplification of the so-called “five-step procedure” originally developed in 2010 by some of the authors. The procedure is applicable to yielding frame structures with a generic along-the-height distribution of inter-storey viscous dampers. It is aimed at guiding the structural engineer through the sizing of both viscous dampers and structural elements making use of an equivalent static analysis approach. First, the peak structural response under earthquake excitation is reduced by imposing an overall reduction factor accounting for both the ductility demand and the viscous damping provided by the added dampers. Second, linear damping coefficients are calculated in order to reduce the structural response according to the selected target damping ratio. Then, analytical formulas allow the estimation of peak velocities and forces in the dissipative devices, and an energy criterion is used to identify the non-linear mechanical characteristics of the actual manufactured viscous dampers. Finally, the internal actions in the structural elements are estimated through the envelope of two equivalent static analyses (ESA). At this initial stage of the research, the procedure appears suitable for the preliminary design phase, while correction factors for the higher modes contributions need to be applied to improve its accuracy, especially for high-rise buildings. A numerical verification of the final behaviour of the system by means of non-linear time-history analyses is recommended. An applicative example is finally developed to highlight the soundness of the procedure
Estimation of maximum damper forces in shear-type buildings subjected to seismic input
No full textIn the last decades, the use of added viscous dampers for the mitigation of the effects due to the seismic action upon the structural elements has been worldwide spread. On the same time, a large research effort has been devoted to the study of the behaviour and performances of building structure equipped with added dampers with special attention to the development of procedures for the optimization of dampers performances through the use of complex algorithms and iterative procedures whose application requires, in most cases, a significant expertise beyond that of the average practitioner and its use is therefore essentially limited to researchers or to large firms specialized in the field of structural control. Nonetheless, less attention has been devoted to the development of practical design procedures. In this regard, on the knowledge of the authors, few practical procedures have been proposed.
Among others, the authors recently proposed a five-step procedure for the dimensioning of inter-storey viscous dampers to be added in frame structures (Silvestri et al., 2010). The procedure aims at guiding the practical design from the choice of a target reduction in the seismic response of the structural system (with respect to the response of a structure without any additional damping devices), to the identification of the corresponding damping ratio and the mechanical characteristics (i.e., damping coefficient values for chosen damping exponent, stiffness of the oil) of the commercially available viscous dampers. The application of the procedure requires the use of a computer program to perform linear and non-linear time-history analysis in order to evaluate the damping force in the added dampers.
In the present paper a simplified version of the 5-step procedure leading to a 3-step procedure which does not require any numerical analyses for the sizing of the viscous dampers is proposed. In detail, simple analytical expressions for the damping forces (leading to a specific target damping ratio) are derived starting from appropriate drift profiles representative of different stiffness distribution along the height
Optimization-in-the-Loop for Energy-Efficient 5G
No full textWe consider the problem of energy-efficient network
management in 5G systems, where backhaul and fronthaul nodes
have both networking and computational capabilities. We devise
an optimization model accounting for the main features of 5G
backhaul and fronthaul, and jointly solve the problems of (i)
node switch on/off, (ii) VNF placement, and (iii) traffic routing.
We implement an optimization module within an application on
top of an SDN controller and NFV orchestrator, thus enabling
swift, high-quality decisions based on current network conditions.
Finally, we validate and test our scheme with real-world power
consumption, network topology and traffic demand, assessing
its performance as well as the relative importance of the main
contributions to the total power consumption of the system.This work was supported by the EU project “5G- Crosshaul: The 5G Integrated fronthaul/backhaul” (grant no. 671598) within the H2020 programme.En prens
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