6,596 research outputs found
La stabile organizzazione digitale: un morto che cammina?
No full textIl presente contributo si propone di analizzare il concetto di stabile organizzazione digitale (detta anche virtuale) alla luce del contesto internazionale ed unionale, nonché la sua traduzione domestica quale risulta dalla lettera f-bis dell’art. 162 del TUIR, non novellata dallo schema di decreto delegato attuativo dell’art. 3 della Legge delega n. 111/2023. Le conclusioni sono nel senso di un auspicato ripensamento del tema da parte del nostro legislatore, tenendo peraltro conto dell’incerta sorte dei lavori sul Pillar 1, e comunque di una revisione della fattispecie di cui all’anzidetta lett. f-bis.The essay is aimed at studying the concept of digital permanent establishment (also known as virtual) in the light of the international and EU context, as well as its domestic translation as resulting from lett. f-bis of the Income Tax Act, not amended in this respect by the bill draft which implements art. 3 of delegation law no. 111/2023. The author concludes by suggesting the legislator, also taking into account the uncertain destiny of Pillar 1 works, to rethink the topic and proposing a new approach to the concept as defined in the above mentioned letter f-bis
Exchange excited f-f transitions in the electron energy-loss-spectra of rare-earth metals
No full textDipole-forbidden f-f multiplet excitations are found to characterize the electron-energy-loss spectra of Pr, Nd, Sm, Gd, Tb, Dy, Ho, and Er when the primary-electron energy is close to the binding energy of the 4d electrons. In Sm and Gd the f-f transitions are also detected at lower primary energies. The identification of the sharp peaks observed in the spectra as f-f excitations comes from straightforward comparison with the absorption spectra of the trivalent ions. The excitation energies of the f-f transitions are found to depend very weakly on the chemical environment. The exchange nature of the f-f excitation process explains the strong decrease of the intensities of the f-f peaks when the primary energy is raised, and is consistent with the resonant enhancement observed for primary energies near the 4d-4f threshold. A similar resonance is also observed in the primary-energy dependence of the intensity of the plasmon peak
La stabile organizzazione “da remoto”: la lett. f-bis) dell’art. 162 del T.U.I.R. e l’approccio OCSE
No full textDi fronte al bivio segnato dal programma di lavoro di fine maggio dell’Inclusive Framework on BEPS, volto a sviluppare “a Consensus Solution to the Tax Challenges Arising from the Digitalisation of the Economy”, ossia l’alternativa consistente nell’intervenire sulla nozione di stabile organizzazione ovvero elaborare un autonomo criterio di collegamento territoriale basato su una new non-physical taxable presence (e consistente, appunto, nel remote yet sustained and significant involvement in the economy of a jurisdiction), il legislatore italiano, con la lett. f-bis) del secondo comma dell’art. 162 Tuir, parrebbe aver imboccato la strada dimezzo.Ha in particolare modificato la nozione di stabile organizzazione materiale per ricomprendervi, in modo almeno apparentemente contraddittorio, anche il caso della nonphysical taxable presence. Il risultato è una previsione di incerto significato (natura antielusiva o nuova fattispecie di stabile organizzazione?) e di dubbia legittimità costituzionale
Grasping Local Participation: The Implementation of the Women, Peace and Security Agenda in the Western Balkans and North Africa
No full textThis article focuses on those “points of fracture” (Kirby and Shepherd 2020, 12) that have manifested in the implementation of the Women, Peace and Security (WPS) Agenda in the Mediterranean region by examining National Action Plans (NAPs) in two distinct sub-regions – the Western Balkans and North Africa. We develop a comparative framework to shed light on the dimension of participation of these plans in four countries where the debate on WPS has reached different stages: Bosnia–Herzegovina, Kosovo, Tunisia and Morocco. By empirically investigating participation as both modality and focus of WPS debate and practice in these countries, we show that NAPs are unable to produce “meaningful local ownership” (Basini and Ryan 2016, 390) and that the international discourse on WPS should be re-thought to resonate with women’s needs, experiences and perspectives in post-conflict and post-revolutionary settings
‘Biological’ revolution and strategies for innovation in pharmaceutical companies
No full textFundamental advances in the life sciences are exerting a profound influence on the structure of the pharmaceutical industry and the strategies of drug companies. The ‘biological’ revolution makes it possible to apply a scientific method to drug research. This paper argues that pharmaceutical companies can take advantage of the new method only if they encourage ‘openness’ of their research. We also offer a framework to explain why innovations in this industry increasingly result from networks of agents with complementary skills and resources. Greater use of scientific knowledge implies that important information for innovation can be expressed in relatively general and universal forms. This eases information exchange, and encourages specialisation and division of labour in drug R&D and marketing. Finally, the possibility of a division of labour in innovation opens new opportunities for medium‐sized national pharmaceutical firms in Europe. Provided that they found their strategies on high‐quality research in specialised niches, they can set up alliances with partners that possess complementary knowledge, and supply resources for clinical development and international marketing. Copyright © 1993, Wiley Blackwell. All rights reserve
Optical Polarimetry for Fundamental Physics
No full textSensitive magneto-optical polarimetry was proposed by E. Iacopini and E. Zavattini in 1979 to detect vacuum electrodynamic non-linearity, in particular Vacuum Magnetic Birefringence (VMB). This process is predicted in QED via the fluctuation of electron–positron virtual pairs but can also be due to hypothetical Axion-Like Particles (ALPs) and/or MilliCharged Particles (MCP). Today ALPs are considered a strong candidate for Dark Matter. Starting in 1992 the PVLAS collaboration, financed by INFN, Italy, attempted to measure VMB conceptually following the original 1979 scheme based on an optical cavity permeated by a time-dependent magnetic field and heterodyne detection. Two setups followed differing basically in the magnet: the first using a rotating superconducting 5.5 T dipole magnet at the Laboratori Nazionali di Legnaro, Legnaro, Italy and the second using two rotating permanent 2.5 T dipole magnets at the INFN section of Ferrara. At present PVLAS is the experiment which has set the best limit in VMB reaching a noise floor within a factor 7 of the predicted QED signal: Δn(QED)=2.5×10−23 @ 2.5 T. It was also shown that the noise floor was due to the optical cavity and a larger magnet is the only solution to increase the signal to noise ratio. The PVLAS experiment ended at the end of 2018. A new effort, VMB@CERN, which plans to use a spare LHC dipole magnet at CERN with a new modified optical scheme, is now being proposed. In this review, a detailed description of the PVLAS effort and the comprehension of its limits leading to a new proposal will be given
Polarisation dynamics of a birefringent Fabry-Perot cavity
No full textOptical Fabry–Perot cavities always show a non-degeneracy of two orthogonal polarisation states. This is due to the unavoidable birefringence of dielectric mirrors whose effects are extremely important in Fabry–Perot-based high-accuracy polarimeters: in birefringent cavities, ellipticities and rotations mix. We have developed and present here a theory of the polarisation state dynamics in a birefringent Fabry–Perot resonator, and we validate it through measurements performed with the polarimeter of the PVLAS experiment. The measurements are performed while a laser is frequency-locked to the cavity, and provide values for the phase difference between the two orthogonal polarisation components introduced by the combination of the two cavity mirrors (equivalent wave-plate) and for the finesse of the cavity. The theoretical formulas and the experimental data agree well showing that the consequences of the mirror birefringence must be taken into account in this and in any other similar experiment
MAcPNN: Mutual Assisted Learning on Data Streams with Temporal Dependence
No full textInternet of Things (IoT) Analytics often involves applying machine learning (ML) models on data streams. In such scenarios, traditional ML paradigms face obstacles related to continuous learning while dealing with concept drifts, temporal dependence, and avoiding forgetting. Moreover, in IoT, different edge devices build up a network. When learning models on those devices, connecting them could be useful in improving performance and reusing others’ knowledge. This work proposes Mutual Assisted Learning, a learning paradigm grounded on Vygotsky’s popular Sociocultural Theory of Cognitive Development. Each device is autonomous and does not need a central orchestrator. Whenever it degrades its performance due to a concept drift, it asks for assistance from others and decides whether their knowledge is useful for solving the new problem. This way, the number of connections is drastically reduced compared to the classical Federated Learning approaches, where the devices communicate at each training round. Every device is equipped with a Continuous Progressive Neural Network (cPNN) to handle the dynamic nature of data streams. We call this implementation Mutual Assisted cPNN (MAcPNN). To implement it, we allow cPNNs for single data point predictions and apply quantization to reduce the memory footprint. Experimental results prove the effectiveness of MAcPNN in boosting performance on synthetic and real data streams
Non-Hermitian time-dependent perturbation theory: Asymmetric transitions and transitionless interactions
No full textThe ordinary time-dependent perturbation theory of quantum mechanics, that describes the interaction of a stationary system with a time-dependent perturbation, predicts that the transition probabilities induced by the perturbation are symmetric with respect to the initial and final states. Here we extend time-dependent perturbation theory into the non-Hermitian realm and consider the transitions in a stationary Hermitian system, described by a self-adjoint Hamiltonian HË0, induced by a time-dependent non-Hermitian interaction f(t)HË1. In the weak interaction (perturbative) limit, the transition probabilities generally turn out to be asymmetric for exchange of initial and final states. In particular, for a temporal shape f(t) of the perturbation with one-sided Fourier spectrum, i.e. with only positive (or negative) frequency components, transitions are fully unidirectional, a result that holds even in the strong interaction regime. Interestingly, we show that non-Hermitian perturbations can be tailored to be transitionless, i.e. the perturbation leaves the system unchanged as if the interaction had not occurred at all, regardless the form of HË0and HË1. As an application of our results, we provide important physical insights into the asymmetric (chiral) behavior of dynamical encircling of an exceptional point in two- and three-level non-Hermitian systems
MD simulation of the Na+-phenylalanine complex in water: competition between cation-pi interaction and aqueous solvation
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