1,776 research outputs found

    Illegal trafficking and unsustainable waste management in Italy: evidence at the regional level

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    The presence of organized crime strongly affects sustainable waste management in Italy. In particular, illegal traf cking of waste has become one of the fastest growing areas of crime and one of the most lucrative industries among organized criminal activities, which has now in ltrated both the Italian urban and hazardous waste management cycle. In this study, we aim to investigate the determinants of the illegal traf cking of waste using waste, economic, and enforcement data in a panel analysis over the period 2002-2013. The topic is particularly relevant, given the high heterogeneity across Italian regions which also relates, and eventually leads, to different environmental performances. Our main ndings reveal that, in most Italian regions, enforcement activities do not exert a signi cant deterrence on criminal behaviors; a negative relationship between enforcement and illegal traf cking of waste can be identi ed only for very high levels of enforcement efforts. Moreover, we nd that the major determinants in uencing the rate of illegal traf cking of waste differ between northern-central and southern regions, con rming the existence of a regional dualism. In particular, while in the northern-central area the crime rate is positively related to the level of education and negatively to the adoption of environmentally sound policies, in southern regions the organized activities for illegal traf cking are negatively related to the degree of education attainment and positively to the endowment of waste management plants

    Reheating in nonminimal derivative coupling model

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    We consider a model with nonminimal derivative coupling of inflaton to gravity. The reheating process during rapid oscillation of the inflaton is studied and the reheating temperature is obtained. Behaviors of the inflaton and produced radiation in this era are discussed.Comment: 16 pages, 5 figures; discussions added; accepted by JCA

    Cumulative effects in inflation with ultra-light entropy modes

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    In multi-field inflation one or more non-adiabatic modes may become light, potentially inducing large levels of isocurvature perturbations in the cosmic microwave background. If in addition these light modes are coupled to the adiabatic mode, they influence its evolution on super horizon scales. Here we consider the case in which a non-adiabatic mode becomes approximately massless ("ultralight") while still coupled to the adiabatic mode, a typical situation that arises with pseudo-Nambu-Goldstone bosons or moduli. This ultralight mode freezes on super-horizon scales and acts as a constant source for the curvature perturbation, making it grow linearly in time and effectively suppressing the isocurvature component. We identify a Stuckelberg-like emergent shift symmetry that underlies this behavior. As inflation lasts for many e-folds, the integrated effect of this source enhances the power spectrum of the adiabatic mode, while keeping the non-adiabatic spectrum approximately untouched. In this case, towards the end of inflation all the fluctuations, adiabatic and non-adiabatic, are dominated by a single degree of freedom.Comment: 27 pages, 1 figure; v2: improved discussions, version published in JCA

    On the Onset of Inflation in Loop Quantum Cosmology

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    Using a Liouville measure, similar to the one proposed recently by Gibbons and Turok, we investigate the probability that single-field inflation with a polynomial potential can last long enough to solve the shortcomings of the standard hot big bang model, within the semiclassical regime of loop quantum cosmology. We conclude that, for such a class of inflationary models and for natural values of the loop quantum cosmology parameters, a successful inflationary scenario is highly improbable.Comment: 16 pages, 6 figures Amended version to appear in Phys. Rev.

    Direct fabrication through electron beam melting technology of custom cranial implants designed in a phantom based haptic

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    Repairing critical human skull injuries requires the production and use of customized cranial implants and involves the integration of computer aided design and manufacturing (CAD and CAM). The main causes for large cranial defects are trauma, cranial tumors, infected craniotomy bone flaps and external neurosurgical decompression. The success of reconstructive cranial surgery depends upon: the preoperative evaluation of the defect, the design and manufacturing of the implant, and the skill of the operating surgeon. Cranial implant design is usually carried out manually using CAD although this process is very time-consuming and the quality of the end product depends wholly upon the skill of the operator. This paper presents an alternative automated method for the design of custom-made cranial plates in a PHANToM \uae-based haptic environment, and their direct fabrication in biocompatible metal using electron beam melting (EBM) technology

    What is a Gene? A Two Sided View

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    The need to account for all currently available experimental observations concerning the gene nature, has reshaped the concept of gene turning it from the essentially mechanistic unit, predominant during the '70s, into a quite abstract open and generalized entity, whose contour appears less defined as compared to the past. Here we propose the essence of the gene to be considered double faced. In this respect genotypic and phenotypic entities of a gene would coexist and mix reciprocally. This harmonizes present knowledge with current definitions and predisposes for remodelling of our thinking as a consequence of future discoveries. A two sided view of the gene also allows to combine the genetic and epigenetic aspects in a unique solution, being structural and functional at the same time and simultaneously able to include the different levels in an overlapping unicum

    LTV stochastic systems stabilization with large and variable input delay

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    In this paper we propose a solution to the state-feedback and output-feedback stabilization problem for linear time-varying stochastic systems affected by arbitrarily large and variable input delay. It is proved that under the proposed controller the underlying stochastic process is exponentially centered and mean square bounded. The solution is given through a set of delay differential equations with cardinality proportional to the delay bound. The predictor is based on the semigroup generated by the closed-loop system in absence of delay, and its computation is described by a numerically reliable and robust method. In the deterministic case this method generates the same optimal trajectories as in the delay-less case
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