The strategic timing of R&D agreements.

We present a model of endogenous formation of R&D agreements among firms in which also the timing of R&D investment is made endogenous. The purpose is to bridge two usually separate streams of literature, the noncooperative formation of R&D alliances and the endogenous timing literature. Our approach allows to consider the formation of R&D agreements over time. It is shown that, when both R&D spillovers and investment costs are sufficiently low, firms may find difficult to maintain a stable R&D agreement due to the strong incentive to invest noncooperatively as leaders. In such a case, to be stable a R&D agreement requires that the joint investment occurs at the initial stage, avoiding any delay. When instead R&D spillover rates are sufficiently high, the cooperation in R&D constitutes a profitable option, although firms also possess the incentive to sequence their investment over time. Finally, when spillovers are asymmetric and the knowledge leaks mainly from the leader to the follower, to invest as follower becomes extremely profitable, making R&D alliances hard to sustain unless firms strategically delay their joint investment in R&D.R&D investment, Spillovers, Endogenous Timing.

Clinical management of a peri-implant giant cell granuloma

Purpose. Implant therapy plays an important role in contemporary dentistry with high rates of long-term success. However, in recent years, the incidence of peri-implantitis and implant failures has significantly increased. The peripheral giant cell granuloma (PGCG) rarely occurs in peri-implant tissues and it is clinically comparable to the lesions associated with natural teeth. Therefore, the study of possible diseases associated with dental implants plays an important role in order to be able to diagnose and treat these conditions. Materials and Methods. This report described a 60-year-old Caucasian male who presented a reddish-purple pedunculated mass, of about 2 cm in diameter, associated with a dental implant and the adjacent natural tooth. Results. An excisional biopsy was performed and the dental implant was not removed. Histological examination provided the diagnosis of PGCG. After 19-month follow-up, there were no signs of recurrence of peri-implantitis around the implant. Conclusion. The correct diagnosis and appropriate surgical treatment of peri-implant giant cell granuloma are very important for a proper management of the lesion in order to preserve the implant prosthetic rehabilitation and prevent recurrences

Childhood overweight-obesity and periodontal diseases: is there a real correlation?

Objective. The association between obesity and periodontitis has been extensively investigated in adults but not in young people. The aim of this study was to examine the association between overweight-obesity and periodontal disease in pediatric subjects. Methods. Controlled cross-sectional study involving 100 school children of both gender (50 M and 50 F) between 7 and 12 years of age (mean age 9,19 +/- 1,57). Two groups were formed based on Body Mass Index value: test group with BMI >= 25 Kg/m(2) and control group with BMI <= 24 Kg/m(2). Diet intake and oral hygiene habits were recorded by a specific questionnaire and the periodontal clinical parameters were evaluated. Results. The periodontal examination in the control group revealed a full-mouth plaque score (FMPS) value equal to 21.86% against 50.08% in the group of patients overweight/obese; the full-mouth bleeding score (FMBS) in the control group amounted to 12.7% against 26.24% of test group. No patient in either group included in the study presented a probing pocket depth (PPD) >= 3, so a significant difference regarding this value was not found. Regarding the frequency and quantity of food consumption, the number of obese patients who did not follow a balanced diet largely exceeded the number of normal-weight patients (70 versus 20%). Conclusions. These results focus the attention on the negative impact of obesity on gingival health in young subjects, probably due to a combination of metabolic and inflammatory profiles and the result of a careless attitude towards prevention diseases of the oral cavit

Geomorphological classification of urban landscapes. The case study of Rome (Italy)

The results of a long-lasting geomorphological survey carried out in Rome are summarized. A method aimed at integrating survey data, historical maps, aerial photographs and archaeological and geomorphological literature produced a geomorphological map of the present-day historical centre. The geomorphology of Rome is related to the paleogeographical conditions prior to the founding of the City; they allow us to recognize the stages of landscape evolution of the ancient Caput Mundi (Capital of the World). The study area has been affected by continuous man-made changes to the drainage network and to the topographic surface over the last 3000 years. It has forced the authors to develop innovative solutions to undertake effective analysis of the urban environment and the legend of the geomorphological map in this peculiar context. The resulting map is useful for urban planning and archaeological research

Performance of mesenchymal cell-scaffold constructs in human oral reconstructive surgery: a systematic review

Background: Different sources of cultured cells combined with different scaffolds (allogenic, xenogeneic, alloplastic or composite materials) have been tested extensively in vitro and in preclinical animal studies, but there have been only a few clinical trials involving humans. Aim: This study reviewed all of the English language literature published between January 1990 and December 2015 to assess the histological performance of different mesenchymal cell-scaffold constructs used for bone regeneration in human oral reconstructive procedures. Methods: An electronic search of the MEDLINE and Cochrane Central Register of Controlled Trials databases complemented by manual searching was conducted to identify studies involving histological evaluation of mesenchymal cell-scaffold constructs in human oral surgical procedures. The methodological quality of randomized controlled clinical trials and controlled clinical trials was assessed using the Cochrane Collaboration tool for assessing the risk of bias. Heterogeneity was assessed using Review Manager software. Considering the heterogeneity, the data collected were reported by descriptive methods and a meta-analysis was applied only to the articles that reported the same outcome measures. The articles were classified and described based on the material scaffolds used. Results: The search identified 1030 titles and 287 abstracts. Full-text analysis was performed for 32 articles, revealing 14 studies that fulfilled the inclusion criteria. Three randomized controlled clinical trials were identified as potentially eligible for inclusion in a meta-analysis. The studies were grouped according to the scaffold materials used: bone allograft (three studies), polyglycolic-polylactic scaffold (four studies), collagen sponge (two studies), and bovine bone matrix (five studies). The stem cells used in these studies had been sourced from the iliac crest, periosteum, dental pulp and intraoral sites. Conclusions: The very small amount of available data makes it impossible to draw any firm conclusions regarding the increase in bone formation in human oral reconstructive procedures when using graft materials engineered with autogenous stem cells

I rapporti di fornitura nella logistica delle emergenze umanitarie

La continua evoluzione del contesto competitivo e della globalizzazione dell’economia in atto da diversi anni sembra confermare la necessità, per gli attori coinvolti, di agire non più isolatamente, ma, piuttosto, di organizzarsi sinergicamente tra loro e con elevata velocità e flessibilità. Quanto sopra è facilmente osservabile nei rapporti di fornitura. L’individuazione di partner giusti, pochi ma affidabili fornitori con cui intrattenere rapporti di lungo termine, sembra essere la scelta strategica ottimale per operare in ambienti altamente turbolenti e mutevoli. Le relazioni di fornitura prese in esame sono quelle legate alla logistica, la cui missione consiste nel garantire il giusto tipo di materiale, nella giusta quantità, nel giusto tempo, nel giusto luogo, secondo le esigenze della domanda. L’ambito oggetto dello studio è quello delle emergenze umanitarie, all’interno del quale la logistica e i rapporti di fornitura costituiscono i punti chiave per la risposta reattiva in soccorso alle popolazioni coinvolte. La logistica delle emergenze è un tema di sicura attualità, sia a livello internazionale che nazionale: si è assistito, infatti, negli ultimi anni, ad un aumento significativo del numero di disastri naturali o causati dall’uomo. Nel settore umanitario operano diversi attori che sono coinvolti nella catena di fornitura che sviluppano partnership intersettoriali tra le organizzazioni no-profit e settore privato. Le prime sono motivate da valori umanitari e religiosi e forniscono sollievo alle popolazioni in difficoltà in tempi ristretti, mentre il settore privato apporta risorse e know how, guardando con sempre maggiore interesse agli impatti positivi provenienti da azioni che rientrano nella responsabilità sociale dell’impresa. Entrambi i soggetti si muovono in un contesto molto incerto, di cui non hanno informazioni, ad esempio, in termini di tempi, luoghi, tipo di disastro, numero di persone che necessitano di assistenza. La Corporate Social Responsibility sembra diventare quindi un vero strumento di benchmarking, che permette di migliorare la reattività logistica apprendendo dalle reciproche esperienze, andando a sostituire la “catena del freddo”, precedentemente usata per l’individuazione delle best practices logistiche. La parte empirica indaga uno degli attori considerati di eccellenza, in campo internazionale, con riguardo alle capacità possedute nella logistica delle emergenze umanitarie: la Protezione Civile Italiana. Il presente lavoro si focalizza sulla gestione delle emergenze che si verificano in ambito nazionale per poi analizzare, più specificatamente, la gestione operativa e i rapporti di fornitura durante il terremoto dell’Abruzzo del 2009

I rapporti di fornitura nella logistica delle emergenze umanitarie

La continua evoluzione del contesto competitivo e della globalizzazione dell’economia in atto da diversi anni sembra confermare la necessità, per gli attori coinvolti, di agire non più isolatamente, ma, piuttosto, di organizzarsi sinergicamente tra loro e con elevata velocità e flessibilità. Quanto sopra è facilmente osservabile nei rapporti di fornitura. L’individuazione di partner giusti, pochi ma affidabili fornitori con cui intrattenere rapporti di lungo termine, sembra essere la scelta strategica ottimale per operare in ambienti altamente turbolenti e mutevoli. Le relazioni di fornitura prese in esame sono quelle legate alla logistica, la cui missione consiste nel garantire il giusto tipo di materiale, nella giusta quantità, nel giusto tempo, nel giusto luogo, secondo le esigenze della domanda. L’ambito oggetto dello studio è quello delle emergenze umanitarie, all’interno del quale la logistica e i rapporti di fornitura costituiscono i punti chiave per la risposta reattiva in soccorso alle popolazioni coinvolte. La logistica delle emergenze è un tema di sicura attualità, sia a livello internazionale che nazionale: si è assistito, infatti, negli ultimi anni, ad un aumento significativo del numero di disastri naturali o causati dall’uomo. Nel settore umanitario operano diversi attori che sono coinvolti nella catena di fornitura che sviluppano partnership intersettoriali tra le organizzazioni no-profit e settore privato. Le prime sono motivate da valori umanitari e religiosi e forniscono sollievo alle popolazioni in difficoltà in tempi ristretti, mentre il settore privato apporta risorse e know how, guardando con sempre maggiore interesse agli impatti positivi provenienti da azioni che rientrano nella responsabilità sociale dell’impresa. Entrambi i soggetti si muovono in un contesto molto incerto, di cui non hanno informazioni, ad esempio, in termini di tempi, luoghi, tipo di disastro, numero di persone che necessitano di assistenza. La Corporate Social Responsibility sembra diventare quindi un vero strumento di benchmarking, che permette di migliorare la reattività logistica apprendendo dalle reciproche esperienze, andando a sostituire la “catena del freddo”, precedentemente usata per l’individuazione delle best practices logistiche. La parte empirica indaga uno degli attori considerati di eccellenza, in campo internazionale, con riguardo alle capacità possedute nella logistica delle emergenze umanitarie: la Protezione Civile Italiana. Il presente lavoro si focalizza sulla gestione delle emergenze che si verificano in ambito nazionale per poi analizzare, più specificatamente, la gestione operativa e i rapporti di fornitura durante il terremoto dell’Abruzzo del 2009

Integration of an increasing-fidelity aerodynamic modelling approach in the conceptual design of hypersonic cruiser

This paper deals with the integration of an increasing-fidelity aerodynamic modelling approach in the conceptual design of hypersonic cruiser. At this purpose, a dedicated methodology has been developed in the framework of the H2020 STRATOFLY project and applied to the STRATOFLY MR3, the Mach 8 waverider reference configuration. Considering the complexity of the concept to be analyzed at conceptual/preliminary design stage, a build-up approach has been adopted, incrementally increasing the complexity of the aerodynamic model, from the clean external configuration up to the complete configuration, including Propulsion Systems Elements and Flight Control Surfaces. In parallel to the aerodynamic analysis, detailed Mission Analyses are performed at each step, benefitting of the incremental versions of the Aerodynamic Database which are used as input. The application of the entire methodology to the reference case-study, allows to estimate design margins to be used at the different steps, to avoid unsolicited under/over-estimations of fuel mass and ranges

Liquid Metals Heat-Pipe solution for hypersonic air-intake leading edge: Conceptual design, numerical analysis and verification

Embedded propulsion systems will allow future hypersonic aircraft to reach amazing levels of performance. However, their peculiar small-radius air-intake leading edges pose serious challenges from the aerothermodynamic, design, integration, and manufacturing standpoints. This paper discloses the methodology developed in the framework of the H2020 STRATOFLY project and specifically tailored to support the conceptual and preliminary design phases of future high-speed transportation systems. The methodology implements an incremental approach which includes multifidelity design, modelling and simulation techniques. The specific application to the MR3, a Mach 8 waverider configuration with an embedded dorsal mounted propulsive subsystem, is reported. Different alternative solutions have been thoroughly analysed, including five liquid metals as fluids (Mercury, Cesium, Potassium, Sodium and Lithium) and relative wick and case materials (Steel, Titanium, Nickel, Inconel® and Tungsten) and three leading-edges materials (CMC, Tungsten with low emissivity painting and Tungsten with high emissivity painting). The analysis of the heat transfer limits (the capillary, entrainment, viscosity, chocking and boiling limits) carried out for all five fluids and relative compatible materials, together with a more accurate FEM analysis, suggest the adoption of a Nickel- Potassium liquid metal heat pipe completely integrated in a platelet air-intake leading edge made of CMC material. Ultimately, the effectiveness of the adopted solution throughout all mission phases has been verified with a detailed numerical model, built upon an electrical analogy

Cooling system of STRATOFLY hypersonic vehicle: conceptual design, numerical analysis and verification

This paper describes the thermal design processes of STRATOFLY hypersonic vehicle cooling system showing either the methodology and the supporting FEM numerical simulations. It focuses on two different regions that are both subjected to severe overheating: air-intake leading edges and the combustion chamber. Final remarks on structure survivability are presented