The postulations á la D'Alembert and á la Cauchy for higher gradient continuum theories are equivalent. A review of existing results

In order to found continuum mechanics, two different postulations have been used. The first, introduced by Lagrange and Piola, starts by postulating how the work expended by internal interactions in a body depends on the virtual velocity field and its gradients. Then, by using the divergence theorem, a representation theorem is found for the volume and contact interactions which can be exerted at the boundary of the considered body. This method assumes an a priori notion of internal work, regards stress tensors as dual of virtual displacements and their gradients, deduces the concept of contact interactions and produces their representation in terms of stresses using integration by parts. The second method, conceived by Cauchy and based on the celebrated tetrahedron argument, starts by postulating the type of contact interactions which can be exerted on the boundary of every (suitably) regular part of a body. Then it proceeds by proving the existence of stress tensors from a balance-type postulate. In this paper, we review some relevant literature on the subject, discussing how the two postulations can be reconciled in the case of higher gradient theories. Finally, we underline the importance of the concept of contact surface, edge and wedge s-order forces

Napoli. Spazi interstiziali e divergenze del ‘tactum’ nell’area della Marina. Note per la rigenerazione urbana

The processes of globalization and alienation that float through the urban contemporary culture permeating atmospheres densely, give us the image of a plural and multiple city. It is constantly in progress as a result of unstoppable dynamics which transmute even the traditional places of permanent configurations into unstable structures, porous and fragmented, tending to hybridization of its constituent parts and to the complexity of relationships. Phenomena of metissage, product by mutual influences among different ethnic groups, give rise to contamination of cultures and seem transposable in a changed identity of the contemporary city. This changes in a fragmented way like rejecting a unitary ‘concept’, and generates hybrid and uneven places which configure the urban archipelago and the mark of a city that abandons the adoption of immutable forms and exists even before its project. In these mechanisms of urbanization, the urban blanks play a fundamental role and in particular those ambiguous spaces and irregular, or residual, whose intrinsic connective properties define the potential of bonding agent, able to sew up and connect the laddered parts of the city. The particular figures and the indefinite concatenation of these 'mestizos' spaces are found in area of Marina in Naples, through the district ‘Porto’ and the district ‘Pendino’. If "space is what impedes that all is in one place", in this area of the city then it would seem left only space for the degradation and marginalization that may arise other urban or environmental infections or contamination. A double meaning of the contamination term is referable to the meaning of the Latin word ‘tactum’ which diverges into two very different (but always interactive) senses. A negative acceptation of ‘contagion’ or ‘infection’ clearly detectable in the area in examined and a positive acceptation of ‘interaction’ or ‘hybridization’, which is very attached to the cognitive value that is assigned by the contemporary culture to the concept of multiplicity. Both connotations are simultaneously found present in the area in examined, although with a different force. For the development of project interventions for urban regeneration, the positive valence of the phenomena of contamination is expressed more specifically in the intrinsic connective energy of the blanks among the buildings which are also called 'in-between' in the current language of contemporary architecture. These blanks are inherently null and shall be available to the intervention of urban regeneration as places appropriate to develop a new urbanity’s principle that constitutes them as a kind of potential infrastructure, giving rise to a unified vision for the city of the future

Santa Maria di Pietraspaccata a Marano di Napoli

L'articolo interpreta i caratteri ambientali del sito di S. Maria di Pietraspaccata in Marano di Napoli attraverso gli esiti di un rilievo già condotto che permettono di rappresentare, attraverso il disegno, la complessità del luogo. Le antichissime cavità rupestri configurano l'ipotesi di un originario insediamento eremitico dislocato su tre principali livelli e costituito 'in negativo' nella parete tufacea (due grotte eremitiche e un ambiente cultuale absidato al livello di accesso, un ambiente con funzione di colatoio orizzontale per la mummificazione dei morti al secondo livello, una grotta per la sistemazione dei corpi al terzo livello) cui si innestarono, in periodo rinascimentale, le strutture murarie destinate a romitorio. Il luogo, diventato successivamente sede di accoglienza per i pellegrini transitanti lungo l'antico tratturo di origine osca che collegò l'entroterra napoletano alla piana flegrea, la cui capacità di rappresentare il tempo emerge dalla contestualità delle due principali fasi generative (quella di scavo e 'sottrazione' materica e quella costruttiva di 'addizione'), accresce la propria dimensione enigmatica nelle numerose e più minute testimonianze stratificate e particolarissimi rinvenimenti, ispessendo i propri strati di memoria e ponendosi come esempio di architettura dimenticata da recuperare all'interno dei processi contemporanei per la rigenerazione territoriale

Editorial: New scenarios, growth paths and opportunities of emerging markets.

Dear readers! We are pleased to present the first issue of the journal Corporate and Business Strategy Review in 2022. The recent global financial crises, as well as the spread of the COVID-19 pandemic, have made it necessary to rethink the basic principles of financial regulation. Nonetheless, financial development remains as strong as ever in emerging markets, although the focus is more on basic elements such as strengthening banking systems and widening the scope of the formal financial system, rather than sophisticated instruments and innovations

Extracting the Cyclical Component in Hours Worked: a Bayesian Approach

The series on average hours worked in the manufacturing sector is a key leading indicator of the U.S. business cycle. The paper deals with robust estimation of the cyclical component for the seasonally adjusted time series. This is achieved by an unobserved components model featuring an irregular component that is represented by a Gaussian mixture with two components. The mixture aims at capturing the kurtosis which characterizes the data. After presenting a Gibbs sampling scheme, we illustrate that the Gaussian mixture model provides a satisfactory representation of the data, allowing for the robust estimation of the cyclical component of per capita hours worked. Another important piece of evidence is that the outlying observations are not scattered randomly throughout the sample, but have a distinctive seasonal pattern. Therefore, seasonal adjustment plays a role. We ¯nally show that, if a °exible seasonal model is adopted for the unadjusted series, the level of outlier contamination is drastically reduced.Gaussian Mixtures, Robust signal extraction, State Space Models, Bayesian model selection, Seasonality

The Predictive Information Content of External Imbalances for Exchange Rate Returns: How Much Is It Worth?

This paper examines the exchange rate predictability stemming from the equilibrium model of international financial adjustment developed by Gourinchas and Rey (2007). Using predictive variables that measure cyclical external imbalances for country pairs, we assess the ability of this model to forecast out-of-sample four major US dollar exchange rates using various economic criteria of model evaluation. The analysis shows that the model provides economic value to a risk-averse investor, delivering substantial utility gains when switching from a portfolio strategy based on the random walk benchmark to one that conditions on cyclical external imbalances.foreign exchange; predictability; global imbalances; fundamentals.