Performance of a linear interference canceller for a ds/cdma synchronous system based on the ekf delay estimator

Since the conventional detector often fails to produce reliable decisions for a CDMA channel, several new multiuser detectors have previously proposed. In the present paper, the authors propose both a simple linear scheme for interference cancellation, which exhibits good performance, and a synchronism scheme based on the extended Kalman filter (EKF) to achieve synchronization among the different users at the base station, for a direct-sequence code-division multiple-access (DS/CDMA) synchronous system. The influence of the synchronism scheme on the performance of the interference canceller is analyzed under Rayleigh multipath fading.Peer ReviewedPostprint (published version

Current concepts in nanostructured contrast media development for In vivo photoacoustic imaging

Photoacoustic (PA) imaging is indeed one of the most promising bioimaging techniques for theranostics applications in humans, allowing for the visualization of blood vessels and melanomas with high spatial resolution. However, in order to overcome the endogenous contrast arising from interfering endogenous species such as haemoglobin and melanin, specific contrast agents need to be developed, allowing PAI to successfully identify targeted contrast in the range of wavelengths in which interference from the biomatrix is minimized. This has been first performed by small molecule dyes, which, however, suffer from some important limitations such as low hydrophilicity and short circulation times. For this reason, scientific research has recently directed its efforts towards the development of nanostructured contrast agents capable of providing efficient PA contrast at low concentrations with low toxicity and high biocompatibility. The principal nanostructures are based on (1) metal and semiconducting nanoparticles, amongst which variously shaped nano-gold plays the main role, (2) carbon nanomaterials, such as carbon nanotubes and graphene, and (3) conjugated polymer nanoparticles. In this review, the principal characteristics of this class of materials are reported and greater focus is directed towards in vivo studies. A detailed analysis is performed on various physical-chemical parameters that define the PA response of reported contrast agents, like absorption coefficients and photoacoustic efficiencies. By comparing the experimental data, this review provides a comprehensive tool for the evaluation of new nanostructured contrast agents for PA imaging

On the influence of the channel impulsional response estimation on the performance of a linear interference canceller for a DS/CDMA system

In a code division multiple access (CDMA) mobile radio communication system, interference from other users is one of the most critical drawbacks due to the lack of perfect orthogonality between user access codes. So far, practical systems have used power control to overcome fading and near/far effects. Another approach which also results in an important improvement of the capacity is the use of interference cancellers. A simple linear interference cancellation scheme for coherent BPSK modulation is proposed and analyzed under Rayleigh multipath fading, and in particular, the influence of the channel impulsive response estimation on the performance of the cancellation scheme has been assessed.Peer ReviewedPostprint (published version

The use of coding and diversity combining for mitigating fading effects in a DS/CDMA system

Spatial diversity is an attractive technology to cope with the fading channel encountered in mobile communications. This paper presents novel closed analytical expressions of the bit-error rate (BER) achievable in a coherent binary phase-shift-keying (CBPSK) direct-sequence code-division multiple-access (DS/CDMA) system for any power delay profile and for either postdetection selection or maximal ratio combining (MRC). In particular, expressions for the cutoff rate Ro and for its related parameter D are also formulated in order to assess the system performance under the consideration of some channel coding schemes. Finally, an exemplary study is carried out in order to illustrate the behavior of a realistic space-diversity code-division multiple-access (CDMA) system according to the analytical expressions that have been derivedPeer Reviewe

Uniqueness in languages with and without articles : Catalan vs Russian

The article compares the interpretation of singular topical nominals in Romance (Catalan) and Slavic (Russian), and its relation to the presence/absence of the article in the overt morphosyntax. The empirical study, presented in this paper, confirmed the theoretical prediction that in Catalan the presence of a definite article conveys uniqueness of the referent, while an indefinite article suggests nonuniqueness. In the absence of articles (in Russian), bare nominals are compatible with both a uniqueness and a non-uniqueness interpretation. The reading of a bare noun phrase is inferred pragmatically, depending on contextual factors and the background knowledge of the interlocutors

Click Chemistry for the Assembly of Gold Nanorods and Silver Nanoparticles

The synthesis of compact nanostructures with highly integratedfunctionalities through the controlled assembly ofnanoparticles (NPs) is potentially of broad interest in researchfields such as drug delivery, multimodal imaging, andelectronic devices. This concept seems to be particularlyimportant in view of the emerging concept of theranostic,according to which both therapeutic and diagnostic capabilitiescan be present in two nanostructures. A key step, however,is how to combine individual nanostructures withoutloosing the original properties

Generarized Cubic Model for BaTiO3_3-like Ferroelectric Substance

We propose an order-disorder type microscopic model for BaTiO$_3$-like Ferroelectric Substance. Our model has three phase transitions and four phases. The symmetry and directions of the polarizations of the ordered phases agree with the experimental results of BaTiO$_3$. The intermediate phases in our model are known as an incompletely ordered phase, which appears in a generalized clock model.Comment: 6 pages, 4figure

How speakers interpret the negative markers no and no … pas in Catalan

This paper reports the results of an experimental investigation designed to test the interpretation of the optional doubling of the negative markers no and pas in Expletive Negation (EN) contexts and in preverbal Negative Concord Items (NCI) contexts in Catalan. We show that in EN contexts a negative interpretation of no is preferred to anexpletive one, with non-negative readings being less widespread than expected from what is described in traditional grammars. In NCI contexts the overt presence of no basically contributes to a single negation interpretation, thus confirming the status of Catalan as aNegative Concord language. We also show that, in the absence of discourse environments, pas in both EN and NCI contexts shows a variable interpretation, a characteristic of negative polarity items. Our results indicate that pas does not increase the amount of negative interpretation of no in EN contexts, or of Double Negation in NCI contexts, but is an item dependent on the interpretation of no. We conclude that the strengthening role of Catalan pas (at stage two of Jespersen's cycle), while associated with the expression of metalinguistic negation, does not reverse the truth or falsity of a proposition