Corporate diversification, coherence and economic performance

Within the diversification literature the concept of corporatecoherence has been referred to as the ability of the firm togenerate and explore synergies of various types. However, theempirical studies have insofar provided only approaches takingexplicitly into account the product/market side of the phenomenon.The present paper operationalizes the concept of corporate coherenceas a dynamic interconnectedness between the company’stechnological competencies and its downstream activities. Italso provides some further empirical evidence on the widelydiscussed relationship between corporate diversification andperformance. Specifically, it offers some (albeit rather weak)evidence that economic performance is positively influencednot by the degree of diversification per se, but by the abilityof the company to increase its corporate coherence.     

Efficient and Adaptive Threshold Signatures for Ad hoc networks

In this paper, we propose a secure, flexible, robust and fully distributed signature service, for ad hoc groups. In order to provide the service, we use a new threshold scheme, that allows to share a secret key among the current group members. The novelty of the scheme is in that it easily and efficiently enables dynamic increase of the threshold, according to the needs of the group, so that the service provides both adaptiveness to the level of threat the ad hoc group is subject to, and availability. We prove the correctness of the protocol and evaluate its efficiency. The changes to the threshold are performed by using a protocol that is efficient in terms of interactions among nodes and per-node required resources, resulting suitable even for resource-constrained settings. Finally, the same proposed scheme allows to detect nodes that attempt to disrupt the service, providing invalid contributions to the distributed signature service.     

Toward a tomographic picture of a Bose-Einstein condensate

The possibilities of applying tomographic techniques to a Bose-Einstein condensate to reconstruct its ground state are investigated by means of numerical simulations. Two situations for which the density-matrix elements can be retrieved from atom counting probabilities are considered. The methods presented here allow one to distinguish among various possible quantum states.     

Fracture behavior of nitrile rubber-cellulose II nanocomposites

Nanocomposites of nitrile rubber (NBR) and cellulose II (Cel II) were prepared by co-coagulation of nitrile rubber latex and cellulose xanthate mixtures. The effect of the addition of increasing amounts of Cell II, varying from 0 to 30 phr, on the mechanical behavior of a NBR was analyzed. The fracture mechanisms of the nitrile rubber-cellulose II (NBR/Cel II) nanocomposites after tension and tear tests was investigated by scanning electron microscopy (SEM) and correlated to the test results. It was found that the addition of Cell II to NBR leads to a gradual change in the stress at break, and the samples with 20 phr of Cel II showed the highest resistance; as the cellulose content is increased to 30 phr, the strain at break decreases. The SEM fractographic analyses of NBR/Cel II nanocomposites, with cellulose content up to 30 support the observed mechanical behavior of the material. The results are presented and discussed. The obtainment of NBR/Cel II nanocomposites was proven by transmission electron microscopy (TEM).     

A cube to learn: a tangible user interface for the design of a learning appliance

In this paper we introduce the design and development of the Learning Cube as a novel tangible learning appliance. Using the common shape of a cube we implemented a general learning platform that supports test based quizzes where questions and answers can be text or image based. Exploiting the physical affordances of the cube and augmenting it with embedded sensors and LCD displays placed on each face, we present different learning appliances as playful learning interfaces for children. Based on the initial observations of the experience with children, we argue that breaking conventions about how a computer has to look like, and providing children with a playful interface is a promising approach to embed and integrate technology into children’s everyday context and activities.     

New signaling molecules in some gram-positive and gram-negative bacteria

A new family of putative signaling molecules having a 2(5H)-furanone configuration has been described in this work. They were released during late exponential or stationary phase in different growth media by some gram-positive bacteria, such as Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus paraplantarum, Lactobacillus sanfranciscensis, Enterococcus faecalis, and a gram-negative species, i.e. Salmonella enterica. A pair of 2(5H)-furanones called furanones A and B occurred in all the conditioned media (CMs) of the species considered. These two molecules showed similar retention times and their spectral data shared the key fragments to include them in the 2(5H)-furanones family. However, some differences were observed in the mass fragmentation profiles. In particular the use of PCA analysis of all the mass fragments enabled the grouping of furanone A profiles of S. enterica, L. helveticus, L. plantarum, L. paraplantarum, L. sanfranciscensis and E. faecalis in one unique cluster with only few exceptions. On the other hand, the mass fragmentation profiles of furanone B of the major part of the species and strains could be grouped together and were differentiated from those of L. helveticus. The specific activity of cell-free supernatants of high density cultures of S. enterica confirmed that the release of active molecules, and specifically of furanones A and B, was cell density dependent. Moreover, a preliminary experiment suspending S. enterica cells into cell-free supernatants of L. helveticus previously exposed to an oxidative stress demonstrated that furanones A and B have a strong interspecific activity. In fact cell autolysis and cell envelope damages were observed with Scanning Electron Microscopy (SEM) in S. enterica.     

Domains of seismic noise response in faulted limestone (central Apennines,Italy): insights into fault-related site effects and seismic hazard

Bulletin of Engineering Geology and the Environment - Studying seismic response at complex geological settings is a challenge due the occurrence of site effects related to widespread...     

Synthesis and Pharmacological Evaluation of α4β2 Nicotinic Ligands with a 3‐Fluoropyrrolidine Nucleus

Nicotinic acetylcholine receptors (nAChRs) play an important role in many central nervous system disorders such as Alzheimer’s and Parkinson’s diseases, schizophrenia, and mood disorders. The α₄β₂ subtype has emerged as an important target for the early diagnosis and amelioration of Alzheimer’s disease symptoms. Herein we report a new class of α₄β₂ receptor ligands characterized by a basic pyrrolidine nucleus, the basicity of which was properly decreased through the insertion of a fluorine atom at the 3‐position, and a pyridine ring carrying at the 3‐position substituents known to positively affect affinity and selectivity toward the α₄β₂ subtype. Derivatives 3‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)‐5‐(phenylethynyl)pyridine ( 11 ) and 3‐((4‐fluorophenyl)ethynyl)‐5‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)pyridine ( 12 ) were found to be the most promising ligands identified in this study, showing good affinity and selectivity for the α₄β₂ subtype and physicochemical properties predictive of a relevant central nervous system penetration.