An interactive semantics of logic programming

We apply to logic programming some recently emerging ideas from the field of reduction-based communicating systems, with the aim of giving evidence of the hidden interactions and the coordination mechanisms that rule the operational machinery of such a programming paradigm. The semantic framework we have chosen for presenting our results is tile logic, which has the advantage of allowing a uniform treatment of goals and observations and of applying abstract categorical tools for proving the results. As main contributions, we mention the finitary presentation of abstract unification, and a concurrent and coordinated abstract semantics consistent with the most common semantics of logic programming. Moreover, the compositionality of the tile semantics is guaranteed by standard results, as it reduces to check that the tile systems associated to logic programs enjoy the tile decomposition property. An extension of the approach for handling constraint systems is also discussed.Comment: 42 pages, 24 figure, 3 tables, to appear in the CUP journal of Theory and Practice of Logic Programmin

The "misunderstood freedom" of demolition and the "distance" between Naples and its periphery. La "libertà malintesa" della demolizione e la "distanza" tra Napoli e la sua periferia.

L'articolo si interroga sul senso della recente decisione di demolire il complesso delle Vele di Scampia da parte del Comune di Napoli sottolineandone il valore architettonico come sperimentazione tipologica e costruttiva tra le più avanzate della modernità e la qualità paesaggistica di un episodio urbano plasticamente ed artisticamente significativo che rimanda a caratteri geografici e topologici, la cui immagine si identifica con la periferia nord di Napoli. E' proprio di fronte a tale valore iconico di tali edifici che ci si chiede quale possa essere il progetto che prenderà il loro posto e la strategia che sarà applicata al conseguente vuoto fatto di enormi distanze da colmar

Performance management in small itallian non-profits

This paper aims at investigating performance management in the context of small non-profits in Italy. The research was based on a small charity in Rome that deals with social inclusion of minors. The analysis was undertaken through two rounds of interviews and by having access to the non-profit’s relevant documents. The research’s results have shown a strong altruistic drive and a lack of formality in performance management practices. Making a clear connection between performance management and its potential benefits to the non-profit’s cause is crucial to favour the adoption of this practice and its utilisation over time

X-ray analysis of the accreting supermassive black hole in the radio galaxy PKS 2251+11

We investigate the dichotomy between jetted and non-jetted Active Galactic Nuclei (AGNs), focusing on the fundamental differences of these two classes in the accretion physics onto the central supermassive black hole (SMBH). Our aim is to study and constrain the structure, kinematics and physical state of the nuclear environment in the Broad Line Radio Galaxy (BLRG) PKS 2251+11. The high X-ray luminosity and the relative proximity make such AGN an ideal candidate for a detailed analysis of the accretion regions in radio galaxies. We performed a spectral and timing analysis of a $\sim$64 ks observation of PKS 2251+11 in the X-ray band with XMM-Newton. We modeled the spectrum considering an absorbed power law superimposed to a reflection component. We performed a time-resolved spectral analysis to search for variability of the X-ray flux and of the individual spectral components. We found that the power law has a photon index $\Gamma=1.8\pm 0.1$, absorbed by an ionized partial covering medium with a column density $N_H=(10.1\pm 0.8) \times 10^{23}$ cm$^{-2}$, a ionization parameter $\log{\xi}=1.3\pm 0.1$ erg s$^{-1}$ cm and a covering factor $f\simeq90\%$. Considering a density of the absorber typical of the Broad Line Region (BLR), its distance from the central SMBH is of the order of $r\sim 0.1$ pc. An Fe K$\alpha$ emission line is found at 6.4 keV, whose intensity shows variability on time scales of hours. We derived that the reflecting material is located at a distance $r\gtrsim600r_s$, where $r_s$ is the Schwarzschild radius. Concerning the X-ray properties, we found that PKS 2251+11 does not differ significantly from the non-jetted AGNs, confirming the validity of the unified model in describing the inner regions around the central SMBH, but the lack of information regarding the state of the very innermost disk and SMBH spin still leave unconstrained the origin of the jet

Sphingosine 1-phosphate axis: a new leader actor in skeletal muscle biology.

Sphingosine 1-phosphate (S1P) is a bioactive lipid involved in the regulation of biological processes such as proliferation, differentiation, motility, and survival. Here we review the role of S1P in the biology and homeostasis of skeletal muscle. S1P derives from the catabolism of sphingomyelin and is produced by sphingosine phosphorylation catalyzed by sphingosine kinase (SK). S1P can act either intracellularly or extracellularly through specific ligation to its five G protein-coupled receptors (GPCR) named S1P receptors (S1PR). Many experimental findings obtained in the last 20 years demonstrate that S1P and its metabolism play a multifaceted role in the regulation of skeletal muscle regeneration. Indeed, this lipid is known to activate muscle-resident satellite cells, regulating their proliferation and differentiation, as well as mesenchymal progenitors such as mesoangioblasts that originate outside skeletal muscle, both involved in tissue repair following an injury or disease. The molecular mechanism of action of S1P in skeletal muscle cell precursors is highly complex, especially because S1P axis is under the control of a number of growth factors and cytokines, canonical regulators of skeletal muscle biology. Moreover, this lipid is crucially involved in the regulation of skeletal muscle contractile properties, responsiveness to insulin, fatigue resistance and tropism. Overall, on the basis of these findings S1P signaling appears to be an appealing pharmacological target for improving skeletal muscle repair. Nevertheless, further understanding is required on the regulation of S1P downstream signaling pathways and the expression of S1PR. This article will resume our current knowledge on S1P signaling in skeletal muscle, hopefully stimulating further investigation in the field, aimed at individuating novel molecular targets for ameliorating skeletal muscle regeneration and reducing fibrosis of the tissue after a trauma or due to skeletal muscle diseases

Ordinare la distanza. Abitare nella città cercando natura

Ordinare la distanza tra le cose progettandola e abitare nella città cercando natura, significa ricercare luoghi comuni e condivisi, investiti dal progetto come unica garanzia di ordine. Vuol dire ribaltare il concetto di spazio aperto come vuoto e assenza, densificandolo, lasciando tracce, creando luoghi dello stare, disponendo gli elementi – naturali o artificiali - secondo un ordinamento geometrico che definisca un sistema architettonico bilanciato, una trama che regoli la distanza mediante dei ritmi, accentramenti, dilatazioni, immettendo relazioni visuali e valori posizionali che orientano l’uomo nel suo percorrere ed abitare lo spazio. Fanno da sfondo a questa trattazione su strumenti e tecniche di progetto dello spazio, alcuni riferimenti alla modernità considerata principale referente del progetto contemporaneo

Polarization reconfigurable patch antenna for compact and low cost UHF RFID reader

This paper presents a patch antenna designed for Ultra High Frequency (UHF) Radio Frequency IDentification (RFID) reader including a reconfigurable feeding for achieving polarization agility. The switchable polarization improves the polarization efficiency in comparison with standard circular polarized antenna solutions. CMOS switches are used in the reconfigurable feeding network for enabling higher power transmission and uncomplicated control with respect to solutions involving varactors and PIN diodes. Moreover, the designed patch antenna and ground planes have reduced size, for best integration of the reader in the required application. The combination of antenna and reconfigurable feeding network has been tested through simulations, showing good performance over the EU RFID frequency band (865-868 MHz). Due to its flexible and inexpensive structure, the proposed reconfigurable feeding system is a promising alternative to standard circular polarized reader antenna approaches

Shape-Memory Polymers in Dentistry: Systematic Review and Patent Landscape Report

To perform a systematic review (SR) of existing literature and a patent landscape report (PLR) regarding the potential applications of shape-memory polymers (SMPs) in dentistry

A quantitative bioassay to determine the inhibitory potency of NGF-TrkA antagonists

In this article, we demonstrate and validate a new bioassay named the NTAB [NGF-TrkA (nerve growth factor-tropomyosin receptor kinase A) antagonist bioassay] for the determination of the inhibitory potency of NGF-TrkA antagonists, based on the inhibition of NGF-dependent proliferation of the human TF1 erythroleukemic cell line.It is well known that NGF holds great therapeutic potential due to its neurotrophic and neuroprotective properties. NGF is also involved in some pathways, however, principally driven by TrkA that, if not correctly regulated, can lead to unwanted pathological outcomes linked to pain, angiogenesis, and cancer.Indeed, there is an increasing interest, from a therapeutic perspective, in designing new effective molecules (antibodies, antibody fragments, or small molecules) able to inhibit the undesired NGF-TrkA pathway. For these reasons, there is an interest to develop functional cell-based assays for determination of the inhibition potency of compounds inhibiting the NGF-TrkA axis. The NTAB presents significant advantages over other published NGF-TrkA functional bioassays, for these reasons: (1) It is quantitative, (2) it measures a pure TrkA response, (3) it is simpler, (4) it is based on a natural biological response, and (5) it is easily scalable from a lab scale to an automated industrial assay.The NTAB assay was validated with a panel of well-characterized NGF-TrkA inhibitors, yielding characteristic dose-response curves, from which the relative strength of the inhibitors was quantitatively determined and used for comparisons. This new bioassay will be very useful to assist in the validation and prioritization of the best inhibitors among a large number of candidates

Phase shifters design for Rotman lens based beamforming network scan range extension

The design of the phase management unit needed for extending the scan range of a 24 GHz array antenna system based on Rotman lens beamforming is presented. The developed phase management unit consists of both static and switchable reflective type phase shifters, whose particular arrangement, in combination with a Rotman lens, allows increasing the maximum steering beam angle by 100%. Finally, the proposed concept is validated through simulation including the complete beamforming network and antenna array system