A management architecture for active networks

In this paper we present an architecture for network and applications management, which is based on the Active Networks paradigm and shows the advantages of network programmability. The stimulus to develop this architecture arises from an actual need to manage a cluster of active nodes, where it is often required to redeploy network assets and modify nodes connectivity. In our architecture, a remote front-end of the managing entity allows the operator to design new network topologies, to check the status of the nodes and to configure them. Moreover, the proposed framework allows to explore an active network, to monitor the active applications, to query each node and to install programmable traps. In order to take advantage of the Active Networks technology, we introduce active SNMP-like MIBs and agents, which are dynamic and programmable. The programmable management agents make tracing distributed applications a feasible task. We propose a general framework that can inter-operate with any active execution environment. In this framework, both the manager and the monitor front-ends communicate with an active node (the Active Network Access Point) through the XML language. A gateway service performs the translation of the queries from XML to an active packet language and injects the code in the network. We demonstrate the implementation of an active network gateway for PLAN (Packet Language for Active Networks) in a forty active nodes testbed. Finally, we discuss an application of the active management architecture to detect the causes of network failures by tracing network events in time

Gedanken experiments on nearly extremal black holes and the Third Law

A gedanken experiment in which a black hole is pushed to spin at its maximal rate by tossing into it a test body is considered. After demonstrating that this is kinematically possible for a test body made of reasonable matter, we focus on its implications for black hole thermodynamics and the apparent violation of the third law (unattainability of the extremal black hole). We argue that this is not an actual violation, due to subtleties in the absorption process of the test body by the black hole, which are not captured by the purely kinematic considerations.Comment: v2: minor edits, references added; v3: minor edits to match published versio

First record of Temnosewellia minor (Platyhelminthes, Temnocephalidae) in Sicily, with a plea for a re-examination of the identity of the publicly available molecular sequences of the genus

Ectosymbiotic temnocephalan flatworms belonging to the genus Temnosewellia were collected on Cherax destructor in an aquaculture farm in Sicily, Italy. This represents the first record of a temnocephalan species for the fauna of the island. Morphological and molecular identification of the collected specimens proved that they belong to the allochthonous species Temnosewellia minor, which was introduced along with crayfishes bred in aquaculture farms. The phylogenetic analyses carried out for the molecular identification of the Sicilian population highlighted some inconsistencies in the grouping of the Temnosewellia sequences available online, thus stressing the opportunity of a careful re-examination of the voucher samples and their identifications. The risks of its unwary introduction in the wild and the need of monitoring its possible impacts on native biota are briefly discussed

Tissue inhibitor of metalloproteinase-1 (TIMP-1) regulates mesenchymal stem cells through let-7f microRNA and Wnt/β-catenin signaling

Tissue inhibitor of metalloproteinases 1 (TIMP-1) is a matrix metalloproteinase (MMP)-independent regulator of growth and apoptosis in various cell types. The receptors and signaling pathways that are involved in the growth factor activities of TIMP-1, however, remain controversial. RNA interference of TIMP-1 has revealed that endogenous TIMP-1 suppresses the proliferation, metabolic activity, and osteogenic differentiation capacity of human mesenchymal stem cells (hMSCs). The knockdown of TIMP-1 in hMSCs activated the Wnt/β-catenin signaling pathway as indicated by the increased stability and nuclear localization of β-catenin in TIMP-1–deficient hMSCs. Moreover, TIMP-1 knockdown cells exhibited enhanced β-catenin transcriptional activity, determined by Wnt/β-catenin target gene expression analysis and a luciferase-based β-catenin– activated reporter assay. An analysis of a mutant form of TIMP-1 that cannot inhibit MMP indicated that the effect of TIMP-1 on β-catenin signaling is MMP independent. Furthermore, the binding of CD63 to TIMP-1 on the surface of hMSCs is essential for the TIMP-1–mediated effects on Wnt/β-catenin signaling. An array analysis of microRNAs (miRNAs) and transfection studies with specific miRNA inhibitors and mimics showed that let-7f miRNA is crucial for the regulation of β-catenin activity and osteogenic differentiation by TIMP-1. Let-7f was up-regulated in TIMP-1–depleted hMSCs and demonstrably reduced axin 2, an antagonist of β-catenin stability. Our results demonstrate that TIMP-1 is a direct regulator of hMSC functions and reveal a regulatory network in which let-7f modulates Wnt/β-catenin activity

Gravity from Quantum Information

It is suggested that the Einstein equation can be derived from Landauer's principle applied to an information erasing process at a local Rindler horizon and Jacobson's idea linking the Einstein equation with thermodynamics. When matter crosses the horizon, the information of the matter disappears and the horizon entanglement entropy increases to compensate the entropy reduction. The Einstein equation describes an information-energy relation during this process, which implies that entropic gravity is related to the quantum entanglement of the vacuum and has a quantum information theoretic origin.Comment: 7 pages, revtex4-1, 2 figures, recent supporting results adde

Campionamento biologico delle catture commerciali Sezione III.C - Variabili biologiche relative al mestiere e dei parametri biologici Sezione III.E - Variabili biologiche relative agli stock del Programma Nazionale

Il campionamento biologico delle catture/sbarcati commerciali, sezione C – Relative al mestiere ed E – Relative agli stock (Campbiol), nell’ambito del Programma Nazionale per la Raccolta Dati Alieutici (PNRDA) (Reg. Ce. N°199/2008; N°665/2008 e decisione della commissione N°949/2008) risulta di grande importanza per conoscere come agisce il prelievo dei diversi ”metiers” sulle diverse specie, in termini di variazioni dell’abbondanza e struttura demografica delle risorse da pesca. Il campionamento biologico risponde, quindi, principalmente alle seguenti esigenze: 1. Ricostruire la struttura demografica delle catture commerciali/sbarchi di ogni specie (in taglia/età), considerando tutti i ”métiers” che incidono significativamente sull’ammontare globale delle catture. 2. Ricostruire il pattern di sfruttamento dei diversi ”métiers” per le diverse specie. 3. Consentire lo studio dei fenomeni biologici rilevanti, quali la crescita ed il ciclo sessuale, che variano nel corso dell’anno. 4. Acquisire informazioni sulla struttura demografica con specifico riferimento allo stadio di maturazione gonadica (maturità/taglia-età) ed alla relazione fra lunghezza e peso corporeo (taglia-peso/età). Il Programma Nazionale prevede il rilievo dei parametri significativi ai fini della caratterizzazione biologica del prodotto della pesca, principalmente nell’ambito di due differenti moduli: Modulo di valutazione del settore della pesca Sezione C – “Variabili biologiche relative al mestiere” Sezione E – “Variabili biologiche relative agli stock

Campionamento biologico delle catture commerciali Sezione III.C - Variabili biologiche relative al mestiere e dei parametri biologici Sezione III.E - Variabili biologiche relative agli stock del Programma Nazionale Sub-area Geografica (GSA16) – Stretto di Sicilia Anno 2015

Il campionamento biologico delle catture/sbarcati commerciali, sezione C – Relative al mestiere ed E – Relative agli stock, nell’ambito del Programma Nazionale per la Raccolta Dati Alieutici (PNRDA) (Reg. Ce. N°199/2008; N°665/2008 e decisione della commissione N°949/2008), ha l’obiettivo di valutare la composizione in taglia e/o età del pescato ed ottenere altre informazioni sulla biologia delle specie bersaglio, quali le chiavi età/lunghezza, la relazione lunghezza/peso, i parametri di crescita, la composizione in sesso e le condizioni di maturità sessuale. Il campionamento delle catture/sbarchi commerciali (campionamento biologico - CAMPBIOL) risulta di grande importanza per conoscere come agisce il prelievo dei diversi ”metiers” sulle diverse specie, in termini di variazioni dell’abbondanza e struttura demografica delle risorse da pesca. Il campionamento biologico risponde, quindi, principalmente alle seguenti esigenze: 1. Ricostruire il pattern di sfruttamento dei diversi ”métiers” per le diverse specie. 2. Ricostruire la struttura demografica delle catture commerciali/sbarchi di ogni specie (in taglia/età), considerando tutti i ”métiers” che incidono significativamente sull’ammontare globale delle catture. 3. Consentire lo studio dei fenomeni biologici rilevanti, quali la crescita ed il ciclo sessuale, che variano nel corso dell’anno. 4. Acquisire informazioni sulla struttura demografica con specifico riferimento allo stadio di maturazione gonadica (maturità/taglia-età) ed alla relazione fra lunghezza e peso corporeo (taglia-peso/età). Il Programma Nazionale prevede il rilievo dei parametri significativi ai fini della caratterizzazione biologica del prodotto della pesca, principalmente nell’ambito di due differenti moduli: Modulo di valutazione del settore della pesca Sezione C – “Variabili biologiche relative al mestiere” Sezione E – “Variabili biologiche relative agli stock

The relativistic fluid dual to vacuum Einstein gravity

We present a construction of a (d+2)-dimensional Ricci-flat metric corresponding to a (d+1)-dimensional relativistic fluid, representing holographically the hydrodynamic regime of a (putative) dual theory. We show how to obtain the metric to arbitrarily high order using a relativistic gradient expansion, and explicitly carry out the computation to second order. The fluid has zero energy density in equilibrium, which implies incompressibility at first order in gradients, and its stress tensor (both at and away from equilibrium) satisfies a quadratic constraint, which determines its energy density away from equilibrium. The entire dynamics to second order is encoded in one first order and six second order transport coefficients, which we compute. We classify entropy currents with non-negative divergence at second order in relativistic gradients. We then verify that the entropy current obtained by pulling back to the fluid surface the area form at the null horizon indeed has a non-negative divergence. We show that there are distinct near-horizon scaling limits that are equivalent either to the relativistic gradient expansion we discuss here, or to the non-relativistic expansion associated with the Navier-Stokes equations discussed in previous works. The latter expansion may be recovered from the present relativistic expansion upon taking a specific non-relativistic limit.Comment: 29 pages, 1 figure; v2: added comments and references, published versio

Local Entropy Current in Higher Curvature Gravity and Rindler Hydrodynamics

In the hydrodynamic regime of field theories the entropy is upgraded to a local entropy current. The entropy current is constructed phenomenologically order by order in the derivative expansion by requiring that its divergence is non-negative. In the framework of the fluid/gravity correspondence, the entropy current of the fluid is mapped to a vector density associated with the event horizon of the dual geometry. In this work we consider the local horizon entropy current for higher-curvature gravitational theories proposed in arXiv:1202.2469, whose flux for stationary solutions is the Wald entropy. In non-stationary cases this definition contains ambiguities, associated with absence of a preferred timelike Killing vector. We argue that these ambiguities can be eliminated in general by choosing the vector that generates the subset of diffeomorphisms preserving a natural gauge condition on the bulk metric. We study a dynamical, perturbed Rindler horizon in Einstein-Gauss-Bonnet gravity setting and compute the bulk dual solution to second order in fluid gradients. We show that the corresponding unambiguous entropy current at second order has a manifestly non-negative divergence.Comment: 28 pages, 2 appendices; v2: added references, fixed typos, one clarifying commen

Protocollo di campionamento per la valutazione della composizione quali/quantitativa delle catture delle flotte pescherecce nella GSA16

Nel documento vengono descritti i protocolli per la rilevazione, il campionamento ed il processamento delle catture (sbarcato e scarto) delle flotte commerciali operanti nello Stretto di Sicilia seguiti da IRBIM-CNR di Mazara del Vallo nel corso del monitoraggio delle attività da pesca condotto nell'ambito del Regolamento Europeo di raccolta dati alieutici (Regulation EU 2017/1004 Data Collection Framework)