The role of codified sources of knowledge in innovation: empirical evidence from Dutch manufacturing

This paper explores ongoing debates about the role that codified forms of knowledge play in fostering firms' and countries' innovative performance. It aims to provide an empirical exploration of the use of codified sources of information for innovation at the sectoral level. Despite considerable interest in David and Foray's (1995) work on the codification of knowledge and the changing nature of innovation due to the use of information and communication technologies, there are relatively few empirical studies that probe the role of codified sources of information in the innovation process. Our goal is to assess 'how' important codified sources of information are for innovation for different sectors and to the innovation system in general. We explore the relationship between the use of codified sources by individual firms and increases in the 'distributional power' of an innovation system, a key component in David and Foray's codification argument. We then link the use of codified sources to different innovative strategies and characteristics of innovation at the firm level. The data used for the analysis is based on The Netherlands Community Innovation Survey (II) for the manufacturing sector. The data set covers 1997 firms in 11 major industries.Innovation, knowledge, manufacturing industries, codification

Local-field effects in silicon nanoclusters

The effect of the local fields on the absorption spectra of silicon nanoclusters (NCs), freestanding or embedded in SiO2, is investigated in the DFT-RPA framework for different size and amorphization of the samples. We show that local field effects have a great influence on the optical absorption of the NCs. Their effect can be described by two separate contributions, both arising from polarization effects at the NC interface. First, local fields produce a reduction of the absorption that is stronger in the low energy limit. This contribution is a direct consequence of the screening induced by polarization effects on the incoming field. Secondly, local fields cause a blue shift on the main absorption peak that has been explained in terms of perturbation of the absorption resonance conditions. Both contributions do not depend either on the NC diameter nor on its amorphization degree, while showing a high sensitivity to the environment enclosing the NCs

Analisi Sistematica, Paleoecologica e Paleobiogeografica della Selaciofauna plio-pleistocenica del Mediterraneo

The systematic, paleoecologic and paleobiogeographic analysis of the Plio-Pleistocene Mediterranean elasmobranch fauna herein discussed provides new relevant data concerning the diversity and disparity of this important marine vertebrate group, in relation to the main climatic, oceanographic and geological evolutionary events. Moreover, This study is part of a wider project in order to understand the main Neogene historical and evolutionary processes involved in the establishment of the present Mediterranean fish fauna. The database used, comprehensive of all the Plio-Pleistocene shark teeth fauna of the Mediterranean area, was compiled from a generic and species revision of historical elasmobranch teeth collections, from a study of the new findings collected the middle Pliocene sections of Rio Merli, Rio dei Ronchi, Rio Cugno and Rio Co di Sasso, and from the lower-middle Pleistocene sections of Fiumefreddo, Grammichele, Archi and Vallone Catrica, as well as from a critical analysis of as many publications as possible figuring and describing Plio-Pleistocene Mediterranean elasmobranch faunas. The qualitative and quantitative analysis of this database provided a general paleoecological and paleobiogeographical pattern of the Mediterranean elasmobranch fauna through the Plio-Pleistocene. A total of 27 species, included into 19 genera, 13 families and 8 orders, have been described. The main systematic results concerned the revision of several teeth, once included in the fossil taxon C. egertoni, from the lower-middle Pliocene of Italy, assigned to the carcharhinid species C. brachyurus, C. falciformis, C. leucas, C. longimanus, C. obscurus, C. perezi, C. plumbeus. Such revision provided the high diversity and disparity of the genus Carcharhinus starting from the lower-middle Pliocene in the Mediterranean, and supported the hypothesis of C. egertoni as a “wasted-basket species”. Moreover, according to the recent diagnosed proposed by Purdy et al. (2001), the shark teeth herein documented and once included in the fossil taxon Isurus hastalis have been assigned to the wide-toothed mako shark Isurus xiphodon. The wide geographic distribution of this fossil taxon during the lower-middle Pliocene (upper Pliocene ?) in the Mediterranean was consistent with the strong presence of marine mammals, mainly pinnipeds and/or small cetaceans, on which I. xiphodon fed. Finally, six large teeth from the Pliocene of Italy have been assigned to the giant-toothed white shark Carcarodon megalodon. This voracious shark was considered extinct between the Upper Miocene-lower Pliocene from the Mediterranean. Therefore, the teeth documented might extend the fossil record of this shark at least during the lower Pliocene into the basin, even if more detailed studies needed to confirm this record. The data provided by the systematic study carried out in this work integrated with those from the critical analysis of the main publications have allowed to recognise a total of 73 elasmobranch species, of which 14 in open nomenclature for the identification at specific level, included in 51 genera, 26 families, and 11 orders. In particular, Carcharhiniformes, representing the 30,6% of the total fauna, was the most diversified shark order of Mediterranean elasmobranch fauna. Moreover, Lamniformes (16,6%), Squaliformes (16,6%) and Myliobatiformes (15,3) provided a relevant part of the elasmobranch fauna diversity. All the other elasmobranch orders, Hexanchiformes (5,5%), Echinorhiniformes (1,4%), Squatiniformes (4,2%), Pristiophoriformes (2,8%), Orectolobiformes (1,4%), Rajiformes (4,2%), and Torpediniformes (1,4%), were poorly represented and mostly subordinated to these four large groups. From a stratigraphic point of view, the teeth recorded in the lower Pleistocene section of Fiumefreddo assigned to the living Apristurus aff. laurussoni represent the first fossil record for the genus Apristurus, while the teeth assigned to Chlamydoselachus anguineus, from the same lower Pleistocene section, represent the first fossil record for this living species. The qualitative and quantitative analysis of the database provided a progressive decrease in diversity and disparity of the elasmobranch fossil record across the Plio-Pleistocene. Moreover, two different evolutionary trend were recognised for the Plio-Pleistocene elasmobranch fauna. A first evolutionary trend involved all the epipelagic and mesopelagic groups of the elasmobranch fauna, characterized however by the less structural variations, mainly related to the progressive disappearance of Miocene relict taxa, such as Isurus xiphodon, Parotodus benedeni or Dipturus olisiponensis, as well as extra-Mediterranean tropical and subtropical species, such as Galeocerdo cuvier, Carcharhinus leucas or C. perezi, showing, starting from the middle Pliocene, a faunal composition very similar to the present. By contrast, a second evolutionary trend involved all those upper mesopelagic and/or bathypelagic shark families, such as Centrophoridae or Dalatiidae, as well as many scyliorinid species. These elasmobranch groups provided the most relevant structural changes across all the Plio-Pleistocene, through several periods of diversification and crisis, probably supported by changes in the deep waters hydrographic conditions of the Mediterranean, as well as by major connection with the near Atlantic Ocean

Development of a open-vessel single-stage respirometer.

This paper describes the development and accuracy analysis of a single-stage respirometer which can be used both in the laboratory for wastewater characterization and in the plant as a process instrument. It is based on an accurate model of parasitic aeration, making the two-stage assumption unnecessary. Its operation is supervised by a real-time software, written in Lab View, managing the various measurement procedures and estimating the wastewater characteristics. Its accuracy is assessed through sensitivity and error propagation analysis, proving superior to the conventional model. A laboratory implementation of the instrument was tested with readily degradable substrate, yielding consistent and accurate respirograms

An Efficient Catalytic Method for Regioselective Sulfenylation of Electron-rich Aza-aromatics at RoomTtemperature

Electron-rich aza-aromatic compounds such as indoles and pyrroles represent systems of particular interest and importance in organic chemistry. An useful methodology for regioselective direct introduction of sulfenyl group on electron-rich aza-aromatics through S-alkyl and S-arylthiophthalimides as sulfenylating agents is described. Catalytic amounts of CeCl3.7H2O-NaI system are crucial to the promotion of this regioselective carbon-sulfur bond-forming Friedel-Crafts reaction. The reaction occurred in mild conditions and the products were obtained in good to excellent yields. Due to the large importance of functionalized indoles among natural compounds and pharmaceutical products, the methodology represents an efficient preparation of sulfenyl aza-aromatics, which are useful intermediates for important organic transformations

Peeking into the Femtosecond Hot-Carrier Dynamics Reveals Unexpected Mechanisms in Plasmonic Photocatalysis

Plasmonic-driven photocatalysis may lead to reaction selectivity that cannot be otherwise achieved. A fundamental role is played by hot carriers, i.e., electrons and holes generated upon plasmonic decay within the metal nanostructure interacting with molecular species. Understanding the elusive microscopic mechanism behind such selectivity is a key step in the rational design of hot-carrier reactions. To accomplish that, we present state-of-the-art multiscale simulations, going beyond density functional theory, of hot-carrier injections for the rate-determining step of a photocatalytic reaction. We focus on carbon dioxide reduction, for which it was experimentally shown that the presence of a rhodium nanocube under illumination leads to the selective production of methane against carbon monoxide. We show that selectivity is due to a (predominantly) direct hole injection from rhodium to the reaction intermediate CHO. Unexpectedly, such an injection does not promote the selective reaction path by favoring proper bond breaking but rather by promoting bonding of the proper molecular fragment to the surface

Characterizing the effects of water distribution system topology modifications on its dynamic behaviour through connectivity metrics

[EN] Water distribution networks (WDNs) are complex combinations of nodes and links and their structure has an impact on their behaviour, considering both quantitative (i.e. related to pipe flows and nodal pressures) and qualitative (i.e. related to water age and quality) aspects. The complexity of WDNs has been the basis of several studies that have resorted to the graph theory to relate connectivity properties to system behaviour (e.g. its reliability and water age/quality), evaluated under the assumption of steady-state conditions. Within this framework, in recent years the tendency toward reducing network interconnection through the closure of isolation valves has emerged, mainly to (i) facilitate its monitoring and management, and (ii) increase flow velocity and reduce water age. However, changes in the topology of a network can affect not only aspects evaluated under the assumption of steady-state conditions, but also its dynamic behaviour. Based on these considerations, the present study investigates whether some metrics derived from graph theory, already applied in the context of networks’ steady-state analyses, can also provide useful indications for assessing the effects of changes in the topological structure, which could be consequences of branching operations, on the dynamic response of a network subjected to users’ activity. The analyses highlight that connectivity metrics can reflect the pressure dynamic behaviour of the hydraulic systems and support in their macroscopic understanding during design and management operations. Thus, their application can be effectively extended from the steady-state to the dynamic framework.Marsili, V.; Alvisi, S.; Maietta, F.; Capponi, C.; Meniconi, S.; Brunone, B.; Franchini, M. (2024). Characterizing the effects of water distribution system topology modifications on its dynamic behaviour through connectivity metrics. Editorial Universitat Politècnica de València. https://doi.org/10.4995/WDSA-CCWI2022.2022.1401