The Predictive Power of Interest Rates Spread for Economic Activity

Since the 1980s, economists argued that the spread between the long-and short-term interest rates is a good predictor of future economic activity. Developing Estrella (2006) study, I investigate the ability of the interest rate spread to predict USA and Germany recessions using a probit model. The results show that the slope of the yield curve well predicts recession periods. I also compare the performance of the spread to the performance of the Chicago Federal Nation Index (CFNAI) — a credited leading indicator for the economic activity of the US — finding out that the yield-spread based forecast anticipates by several months the CFNAI forecast.

Optimal randomness certification in the quantum steering and prepare-and-measure scenarios

Quantum mechanics predicts the existence of intrinsically random processes. Contrary to classical randomness, this lack of predictability can not be attributed to ignorance or lack of control. Here we find the optimal method to quantify the amount of local or global randomness that can be extracted in two scenarios: (i) the quantum steering scenario, where two parties measure a bipartite system in an unknown state but one of them does not trust his measurement apparatus, and (ii) the prepare-and-measure scenario, where additionally the quantum state is known. We use our methods to compute the maximal amount of local and global randomness that can be certified by measuring systems subject to noise and losses and show that local randomness can be certified from a single measurement if and only if the detectors used in the test have detection efficiency higher than 50%.Comment: 11 pages, 6 figures. v2: Published versio

MOBILITY AND URBAN AREAS INTERCHANGE

Urban transportation today is matching more and more new needs for mobility due to the continuous change of urban functions. Nowadays, the concept of the city transcends the vision of a constructed and circumscribed space to reach the valence of a service system, linked by an infrastructure network which allows the same functionality. In this sense, mobility has suffered substantial modification in adapting to the changing needs of the local populations. Thus, the interpretation of urban mobility must change in satisfying three instances: the routes, means of transport, and mode change. Above all, the mode change needs to be adequately exploited to support new mobility. It is necessary to improve integration between different transfer modality, and to affect the propensity (favored by major guarantees of quality of travel) of the users to the use of public transport. This work is aimed to identify those parameters which are useful in planning an area where two or more transport networks can be employed. Thus, even if they are hierarchically different, they must be connected and their functions and equipment must be concentrated to facilitate the transition from one system of transport to another

Prediction of acute kidney injury using the Electronic Medical Records of a pediatric cardiac intensive care unit

Acute Kidney Injury (AKI) is a frequent complication in hospitalized patients significantly associated with mortality, length of stay, and healthcare cost. Management of AKI presents an important challenge and clinicians may be helped by robust prediction models for risk evaluation, foster prevention, and recognition. The advances in clinical informatics and the increasing availability of electronic medical records (EMR) have favored the development of predictive models of risk estimation in AKI. In this dissertation, we analyze the problem of predicting the AKI stage during the patient’s stay in the intensive care unit using retrospectively the Electronic medical records (EMRs) recently introduced in the Pediatric Intensive Care Unit (PCICU) of "Ospedale Pediatrico Bambino Gesù". After the initial phase of data selection, extraction, and management of missing data, we develop a random forest (RF) classification model including a variable selection step with the aim of predicting the stage of AKI 48 hours in advance in both binary and multiclass cases. The performances obtained in terms of Area under the ROC Curve (AUC-ROC) for binary cases and accuracy for multiclass cases are always very good compared with other recent attempts in the literature. The list of the most important variables obtained in the various classifications highlights the importance of some of the expected variables (such as creatinine) reported in other studies in the literature but also the presence of variables that are specific to pediatric patients under examination (such as PIM3). Moreover, we develop other classifications using the Generalized Additive Models (GAMS) and Bayesian network (BN) models that have the benefit of offering a more interpretable approach. Although these results are inferior to the RF, they are comparable with many outcomes reported in the literature. The plot obtained with GAMs and the structure of the directed acyclic graph (DAG) achieved with BN are consistent with a possible medical explanation and would present further interpretation hints for the doctors about the onset of AKI. Finally, we observe that all implemented models confirm the possibility of making an accurate prediction of the AKI stage using the PCICU. These models can be potentially included in a web interface and, in perspective, be integrated into the EMR of PCICU. This tool would allow the doctors to predict prospectively the patient’s stage of AKI and evaluate how to intervene if necessary. In order to proceed with this, it would be necessary for the future to implement the export of a larger dataset adding new data acquired in the meantime in PCICU

Business Model in Air Transport: Evolution of Innovation Concept

With the advent of the knowledge society, new opportunities, business models and concepts have emerged in most industrial sectors and in particular in the transport sector. The European air travel market, dominated by airlines, influenced to varying degrees from their countries of origin, has been, since the early nineties, completely revolutionized by the entrance in the competitive arena of several small companies, which, in accordance with the principles of „disruptive innovation‟, have completely changed the field of passenger transport. To understand how this was possible, it is necessary to investigate, just with the help of these new tools of Strategic Management as the business models, about the way in which these airlines are able to generate their business and create value. This work aims to analyse the close relationship between innovation of product / service and corporate business model in order to understand the dynamics of the relationship. Various contributions from literature showed how the concept of innovation within the company has evolved over the years and what were the approaches used to study it. This analysis begins with the study of the contributions of Schumpeter, the first economist to write about innovation and author of the dynamic development model and creator of the first distinction between innovation and invention. His theories have made a major contribution in this area, but none the less were also constructively criticized by other economists such as Freeman, who introduced the concept of incremental innovation and analysed the factors triggering innovation. Albernathy and Clark then added another fundamental element of analysis: the competitive environment. They studied the influence of innovation on those factors that are considered essential to achieve a competitive advantage. The same Albernathy, with Utterback, then studied the dynamics of innovations over time. Each of the cited authors analysed the phenomenon of innovation in a different light and all of their contributions allows for a broad and comprehensive concept. The picture is completed by adding the recent contributions of Christensen, who has taken up and deepened the concepts of "sustaining innovation" and " disruptive innovation" and, especially, began to highlight how essential it is that innovation is supported by a suitable business model. In this regard, he has shown that even the same business model can be object of innovation and that this type of innovation is one of the main drivers of the creation of competitive advantage

Quantum topology and modularity

Mathematics is an extremely powerful tool in physics. The effectiveness of mathematics in physics has driven vivid discussions on whether mathematics is just a tool in physical research or if there is something fundamentally mathematical about Nature itself. This thesis presents advances made towards various mathematical problems following a paradigm inversion between physics and mathematics: one where physics is used as a tool for mathematical research.The central object of discussion is the Ẑ-invariant, a quantum invariant for 3-manifolds which is physically constructed as the half-index of a 3D reduction of a 6D N=(2,0) M-theory. The Ẑ-invariant provides bridges connecting physics to disparate disciplines of otherwise disconnected disciplines of mathematics, including Low dimensional and Quantum Topology, Modularity and Vertex Operator algebras. Following an introduction and a background chapter, where all the necessary prerequisites for the remaining chapters are presented, this thesis presents advances made towards the elucidation of the structures inherent in these connections. Chapter 3 focusses on the connections between the Ẑ-invariant and log-VOAs. It is found that Ẑ-invariants for certain families of 3-manifolds may be regarded as linear combinations of characters of log-VOAs. Chapter 4 generalizes the known modular properties of Ẑ-invariants. It is shown that classes of Ẑ-invariants for certain families of 3-manifolds are higher rank quantum modular forms. In Chapter 5 defect Ẑ-invariant are introduced as well as it discusses their modular properties. Moreover, previously unknown Ẑ-invariants are proposed which are shown to relate to characters of cone-VOAs

Market and Company Dimension in the Internet Age

The analysis and the study of market and company dimension takes on a particular interest for those who analyze and study the set of problems typical of company economy. The starting point, nowadays, is the verification, from most experts openly shown, of the strict correlation of the two phenomena and, actually of their mutual influence. The analysis of these ones assumes a particular attention in light of what is happening in front of our eyes. Those which appeared irrefutable certainties are now completely put into play again, very often, for determined aspects, completely overturned in regard to the previous certainties. Our effort will consist in a detailed study of the two phenomena included in the great world of internet. The company is a very complex organism. It consists of the organization in its inner of a set of functions, which have to be dimensioned one to the others to obtain a mutual functionality and a harmonic development. The organization of the company functions is a binding necessity for adherence of them to the needs and expectations of market to which the company turns its attention and interest. This combination of functions with the chosen external environment represents the focal point of our interest. It is well clear that the changes which intervene either in one or in other environment, that must combine, necessarily produce some variations that assure the lingering of harmony already reached in the two sections

Necessary detection efficiencies for secure quantum key distribution and bound randomness

In recent years, several hacking attacks have broken the security of quantum cryptography implementations by exploiting the presence of losses and the ability of the eavesdropper to tune detection efficiencies. We present a simple attack of this form that applies to any protocol in which the key is constructed from the results of untrusted measurements performed on particles coming from an insecure source or channel. Because of its generality, the attack applies to a large class of protocols, from standard prepare-and-measure to device-independent schemes. Our attack gives bounds on the critical detection efficiencies necessary for secure quantum distribution, which show that the implementation of most partly device independent solutions is, from the point of view of detection efficiency, almost as demanding as fully device-independent ones. We also show how our attack implies the existence of a form of bound randomness, namely non-local correlations in which a non-signalling eavesdropper can find out a posteriori the result of any implemented measurement.Comment: 5 pages. v2: new title, published versio

Detection loophole attacks on semi-device-independent quantum and classical protocols

Semi-device-independent quantum protocols realize information tasks - e.g. secure key distribution, random access coding, and randomness generation - in a scenario where no assumption on the internal working of the devices used in the protocol is made, except their dimension. These protocols offer two main advantages: first, their implementation is often less demanding than fully-device-independent protocols. Second, they are more secure than their device-dependent counterparts. Their classical analogous is represented by random access codes, which provide a general framework for describing one-sided classical communication tasks. We discuss conditions under which detection inefficiencies can be exploited by a malicious provider to fake the performance of semi-device-independent quantum and classical protocols - and how to prevent it.Comment: 13 pages, 1 figure, published versio

Areas and Perspectives of the World Wine Market

This paper focuses on offering a synthetic picture of the areas and perspectives of the world wine market as observed in its international dimension. In the last thirty years, important changes have succeeded in quantitative terms as a result of qualitative expectations from the public and market structure. Henceforth, the different actors must restructure their strategies and behaviours. Apparently, the wine sector will be able to see a sensitive concentration process among companies positioned at the lower market segments. There is a situation in which a relatively reduced number of large companies dominates this part of the market. It exploits some key success factors, which is a range of offers based on several brands of international fame, eventually with a strong territorial connotation. It is assigned to specific public segments, economies of scale, and a capillary distribution optimized with respect to costs. Though the different companies categories appear in competition in the wine market, nonetheless, they are allies in the crucial battle for the support and development of wine consumption. This, as we have already seen, competes in a now definitely saturated beverage market. The consumption of wine, in particular, appears threatened by a difficulty in approaching young people for its daily consumption in traditional consumer countries. There is amassive anti-alcohol campaign in many countries in addition to the encourged position of theWorld Health Organization that tends to become increasingly hostile to alcohol and in which wine is put on the same level as all the other alcoholic beverage