353 research outputs found
Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a periodically multilayered isotropic dielectric material
Multiple p- and s-polarized compound surface plasmon-polariton (SPP) waves at
a fixed frequency can be guided by a structure consisting of a metal layer
sandwiched between a homogeneous isotropic dielectric (HID) material and a
periodic multilayered isotropic dielectric (PMLID) material. For any thickness
of the metal layer, at least one compound SPP wave must exist. It possesses the
p-polarization state, is strongly bound to the metal/HID interface when the
metal thickness is large but to both metal/dielectric interfaces when the metal
thickness is small. When the metal layer vanishes, this compound SPP wave
transmutes into a Tamm wave. Additional compound SPP waves exist, depending on
the thickness of the metal layer, the relative permittivity of the HID
material, and the period and the composition of the PMLID material. Some of
these are p polarized, the others being s polarized. All of them differ in
phase speed, attenuation rate, and field profile, even though all are excitable
at the same frequency. The multiplicity and the dependence of the number of
compound SPP waves on the relative permittivity of the HID material when the
metal layer is thin could be useful for optical sensing applications.Comment: 17 page
Compound surface-plasmon-polariton waves guided by a thin metal layer sandwiched between a homogeneous isotropic dielectric material and a structurally chiral material
Multiple compound surface plasmon-polariton (SPP) waves can be guided by a
structure consisting of a sufficiently thick layer of metal sandwiched between
a homogeneous isotropic dielectric (HID) material and a dielectric structurally
chiral material (SCM). The compound SPP waves are strongly bound to both
metal/dielectric interfaces when the thickness of the metal layer is comparable
to the skin depth but just to one of the two interfaces when the thickness is
much larger. The compound SPP waves differ in phase speed, attenuation rate,
and field profile, even though all are excitable at the same frequency. Some
compound SPP waves are not greatly affected by the choice of the direction of
propagation in the transverse plane but others are, depending on metal
thickness. For fixed metal thickness, the number of compound SPP waves depends
on the relative permittivity of the HID material, which can be useful for
sensing applications
Confianza e información en el derecho contractual europeo
The paper analyses the reasons for a correct formation of the exchange contract in a market economy, in order to safeguard its operation in a competitive sense. In particular, it highlights the importance of protecting the trust of the contracting parties with respect to reciprocal disclosure obligations that prevent the conclusion of asymmetric contracts, which by definition are unfair and inefficient
Pharmacokinetic/pharmacodynamic (PK/PD) considerations in the management of Gram-positive bacteraemia
tolerability and safety of antifungal drugs
When treating critically ill patients, as those with fungal infections, attention should be focused on the appropriate use of drugs, especially in terms of dose, safety, and tolerability. The fungal infection itself and the concomitant physiological disorders concur to increase the risk of mortality in these patients, therefore the use of any antifungal agent should be carefully evaluated, considering both the direct action on the target fungus and the adverse effects eventually caused. Among antifungal drugs, echinocandins have the greatest tolerability. In fact, unlike amphotericin B, showing nephrotoxicity, and azoles, which are hepatotoxic, the use of echinocandins doesn't result in major adverse events
SALIENZA E CONTATTO IN CONTESTO ITALOROMANZO: PROSPETTIVE TEORICHE E FENOMENI LINGUISTICI
Il contributo si sofferma sul rapporto tra salienza e contatto italiano-dialetto con l’obiettivo, da un lato, di esplorare e comprendere l’effettiva validità e applicabilità in contesto italoromanzo delle principali modellizzazioni diffuse in letteratura, dall’altro, di individuare e proporre percorsi di analisi e specifiche categorie che passano trovare un più immediato riscontro nella realtà indagata.
Dopo aver discusso i principali aspetti di ordine linguistico ed extralinguistico che caratterizzano le più note teorie riguardanti la salienza, ci si concentrerà sulla realtà sociolinguistica italoromanza a partire da un caso di studio sul contatto italiano-dialetto in Sicilia tratto dall’analisi di alcuni dati lessicali della sezione sociovariazionale dell’Atlante Linguistico della Sicilia. In tal senso, si dimostrerà l’elevata salienza dei tratti fonetici e morfologici della varietà locale, aspetto suggerito in modo esplicito dagli informatori nel corso delle interviste. Inoltre, si cercherà di verificare l’efficacia dei presupposti teorici, dei fenomeni e degli esiti previsti dai modelli considerati, aspetto che spingerà verso la necessità di una più precisa e, al contempo, ampia definizione del concetto di salienza nonché di nuove categorie attraverso cui definire quei tratti oggetto di una elevata consapevolezza da parte dei parlanti.
Salience and contact in an Italo-Roman context: theoretical perspectives and linguistic phenomena
This work deals with the relationship between salience and Italian-dialect contact trying to comprehend the correspondence in the Italo-Romance context of the main theories diffused in literature and to propose a new analytical approach and specific categories which better fit this specific case of language contact. After discussing the main linguistic and extralinguistic aspects of the well-known theories concerning salience, the study focusses on a case study about the contact between Italian and Sicilian deriving from the lexical data of the Atlante Linguistico della Sicilia. In particular, as suggested by the same speakers during the interviews, the analysis makes clear the salience of the phonetic and morphological features of the local variety, also demonstrating the lack of correspondence of the salience theories and models taken into account. This leads to a more specific and, at the same time, broader definition of salience as well as to new categories by which classify those linguistic elements of the local variety characterized by a high level of awareness by the speakers
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
Editoriale
<a href="http://dx.doi.org/10.7175/rhc.v4i2s.871">http://dx.doi.org/10.7175/rhc.v4i2s.871</a
Prophylaxis and treatment of invasive fungal infections in hematological patients
The evidence from the literature strongly support antifungal prophylaxis in high risk haematological patients, such as patients with AML during remission induction chemotherapy and alloHSCT patients. Current antifungal prophylaxis guidelines for high risk patients recommend azoles (fluconazole, posaconazole, voriconazole) and echinocandins (micafungin) with the strongest level of evidence. In terms of treatment, the choice between empiric therapy (or fever driven) and pre-emptive therapy (or diagnostic driven) is still debated. Not a single therapeutic strategy is appropriate in every patients, in particular empirical antifungal therapy may be recommended in patients at very high risk, while a pre-emptive approach may be advised for those at standard risk. In order to exploit the synergistic and/or additive effect of two antifungal drugs it's possible to combine two agents that work with different mechanisms of action (e.g. echinocandins + azoles or polyenes). Once the treatment has been initiated we should consider the therapeutic drug monitoring (TDM) of the drugs, especially when the pharmacokinetic variability is high and the dose-concentration effect relationships is not predictable (e.g. for itraconazole, voriconazole and posaconazole)
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