First record of the non-pollinating fig wasp Odontofroggatia galili Wiebes, 1980 from Malta (Hymenoptera, Chalcidoidea, Agaonidae)

The fig wasp Odontofroggatia galili is reported for the first time from Malta. Odontofroggatia is a non-pollinating fig wasp genus associated with a narrow range of host plant species, among them Ficus microcarpa, a widespread ornamental tree native to Asia.peer-reviewe

Convolutive superposition for multicarrier cognitive radio systems

Recently, we proposed a spectrum-sharing paradigm for single-carrier cognitive radio (CR) networks, where a secondary user (SU) is able to maintain or even improve the performance of a primary user (PU) transmission, while also obtaining a low-data rate channel for its own communication. According to such a scheme, a simple multiplication is used to superimpose one SU symbol on a block of multiple PU symbols.The scope of this paper is to extend such a paradigm to a multicarrier CR network, where the PU employs an orthogonal frequency-division multiplexing (OFDM) modulation scheme. To improve its achievable data rate, besides transmitting over the subcarriers unused by the PU, the SU is also allowed to transmit multiple block-precoded symbols in parallel over the OFDM subcarriers used by the primary system. Specifically, the SU convolves its block-precoded symbols with the received PU data in the time-domain, which gives rise to the term convolutive superposition. An information-theoretic analysis of the proposed scheme is developed, which considers different amounts of network state information at the secondary transmitter, as well as different precoding strategies for the SU. Extensive simulations illustrate the merits of our analysis and designs, in comparison with conventional CR schemes, by considering as performance indicators the ergodic capacity of the considered systems.Comment: 29 pages, 8 figure

LUCRETIUS AND HIS DE RERUM NATURA SIX CENTURIES AFTER A CONVERSATION WITH DAVID SEDLEY

In this interview David Sedley reflects on some important points of hisseminal interpretation of Lucretius’ De rerum natura six centuries after its discovery in1417 by Poggio Bracciolini (Terranuova, now Terranuova Bracciolini, 1380 – Florence,1459)

ANCORA SULLO STATUTO VERITATIVO DELLA SENSAZIONE IN EPICURO

The main goals of this article are, on the one hand, to show the peculiar features of the Epicurean view of sense-perception (aisthesis), the first criterion of truth of Epicurus’ canonic; and, on the other hand, to critically discuss a recent contribution by Alexander Bown (“Epicurus on Truth and Falsehood”, Phronesis, 61 (4), 2016, p. 463-503), which deals with Epicurus’ double notion of truth (i.e. the truth of sense-perceptions/aistheseis and the truth of opinions/hypolepseis). Besides Book 10 of Diogenes Laertius’ Lives of Eminent Philosophers and Epicurus’ Letter to Herodotus, columns LXXII-LXXIII of PHerc. 1012 (including a work by the Epicurean philosopher Demetrius Lacon) and a passage from Sextus Empiricus’ Against the Logicians (M, VIII, 9) will be examined in order to explain the meaning of truth linked by Epicurus to perceptible objects (aistheta)

STiCMAC: A MAC Protocol for Robust Space-Time Coding in Cooperative Wireless LANs

Relay-assisted cooperative wireless communication has been shown to have significant performance gains over the legacy direct transmission scheme. Compared with single relay based cooperation schemes, utilizing multiple relays further improves the reliability and rate of transmissions. Distributed space-time coding (DSTC), as one of the schemes to utilize multiple relays, requires tight coordination between relays and does not perform well in a distributed environment with mobility. In this paper, a cooperative medium access control (MAC) layer protocol, called \emph{STiCMAC}, is designed to allow multiple relays to transmit at the same time in an IEEE 802.11 network. The transmission is based on a novel DSTC scheme called \emph{randomized distributed space-time coding} (\emph{R-DSTC}), which requires minimum coordination. Unlike conventional cooperation schemes that pick nodes with good links, \emph{STiCMAC} picks a \emph{transmission mode} that could most improve the end-to-end data rate. Any station that correctly receives from the source can act as a relay and participate in forwarding. The MAC protocol is implemented in a fully decentralized manner and is able to opportunistically recruit relays on the fly, thus making it \emph{robust} to channel variations and user mobility. Simulation results show that the network capacity and delay performance are greatly improved, especially in a mobile environment.Comment: This paper is a revised version of a paper with the same name submitted to IEEE Transaction on Wireless Communications. STiCMAC protocol with RTS/CTS turned off is presented in the appendix of this draf

STIXnet: A Novel and Modular Solution for Extracting All STIX Objects in CTI Reports

The automatic extraction of information from Cyber Threat Intelligence (CTI) reports is crucial in risk management. The increased frequency of the publications of these reports has led researchers to develop new systems for automatically recovering different types of entities and relations from textual data. Most state-of-the-art models leverage Natural Language Processing (NLP) techniques, which perform greatly in extracting a few types of entities at a time but cannot detect heterogeneous data or their relations. Furthermore, several paradigms, such as STIX, have become de facto standards in the CTI community and dictate a formal categorization of different entities and relations to enable organizations to share data consistently. This paper presents STIXnet, the first solution for the automated extraction of all STIX entities and relationships in CTI reports. Through the use of NLP techniques and an interactive Knowledge Base (KB) of entities, our approach obtains F1 scores comparable to state-of-the-art models for entity extraction (0.916) and relation extraction (0.724) while considering significantly more types of entities and relations. Moreover, STIXnet constitutes a modular and extensible framework that manages and coordinates different modules to merge their contributions uniquely and exhaustively. With our approach, researchers and organizations can extend their Information Extraction (IE) capabilities by integrating the efforts of several techniques without needing to develop new tools from scratch.Comment: 11 pages, 3 figure

The impact of the EU Emissions Trading System on low-carbon technological change: the empirical evidence

This paper reviews the empirical literature analysing the effects of the EU Emissions Trading System (EU ETS) on low-carbon technological change. The emerging evidence is assessed, with references to both relevant economic concepts and the evolving regulation of the EU ETS through time. The two most robust indications of the literature are: a) the EU ETS appears to have been more effective in stimulating innovation of low-carbon technologies rather than their adoption; and b) free allocation (grandfathering) tended to hamper low-carbon investments in Phases I (2005-2007) and II (2008-2012). However, a complete general picture of the impact of the EU ETS on low-carbon technological change is missing. The main gap regards the lack of empirical evidence for Phase III (2013-2020). Especially econometric studies are few, due to the lack of suitable databases accessible to researchers - a problem that the relevant public authorities are urged to address. Thanks to the recent reforms of the EU ETS, the incentives for innovation and adoption of low-carbon technologies are probably stronger today than ever before