Complex-valued B-spline neural networks for modeling and inverting Hammerstein systems

Many communication signal processing applications involve modelling and inverting complex-valued (CV) Hammerstein systems. We develops a new CV B-spline neural network approach for efficient identification of the CV Hammerstein system and effective inversion of the estimated CV Hammerstein model. Specifically, the CV nonlinear static function in the Hammerstein system is represented using the tensor product from two univariate B-spline neural networks. An efficient alternating least squares estimation method is adopted for identifying the CV linear dynamic model’s coefficients and the CV B-spline neural network’s weights, which yields the closed-form solutions for both the linear dynamic model’s coefficients and the B-spline neural network’s weights, and this estimation process is guaranteed to converge very fast to a unique minimum solution. Furthermore, an accurate inversion of the CV Hammerstein system can readily be obtained using the estimated model. In particular, the inversion of the CV nonlinear static function in the Hammerstein system can be calculated effectively using a Gaussian-Newton algorithm, which naturally incorporates the efficient De Boor algorithm with both the B-spline curve and first order derivative recursions. The effectiveness of our approach is demonstrated using the application to equalisation of Hammerstein channels.

How remote are R&D labs? Distance factors and international innovative activities

This paper shows that value creation by multinational enterprises (MNEs) is the result of activities where geographic distance effects can be overcome. We submit that geographic distance has a relatively low impact on international research and development (R&D) investments, owing to the spiky nature of innovation, and to the unique ability of MNEs to absorb and transfer knowledge on a global scale. On the one hand, MNEs need to set up their labs as close as possible to specialized technology clusters where valuable knowledge is concentrated, largely regardless of distance from their home base. On the other, MNEs have historically developed technical and organizational competencies that enable them to transfer knowledge within their internal networks and across technology clusters at relatively low cost. Using data on R&D and manufacturing investments of 6320 firms in 59 countries, we find that geographic distance has a lower negative impact on the probability of setting up R&D than manufacturing plants. Furthermore, once measures of institutional proximity are accounted for, MNEs are equally likely to set up R&D labs in nearby or in more remote locations. This result is driven by MNEs based in Triad countries, whereas for non-Triad MNEs the effect of geographic distance on cross-border R&D is negative and significant.

Detection of assemblages A and B of Giardia duodenalis in water and sewage from Sao Paulo state, Brazil

Giardia duodenalis is a protozoan that parasitizes humans and other mammals and causes giardiasis. Although its isolates have been divided into seven assemblages, named A to G, only A and B have been detected in human faeces. Assemblage A isolates are commonly divided into two genotypes, AI and AII. Even though information about the presence of this protozoan in water and sewage is available in Brazil, it is important to verify the distribution of different assemblages that might be present, which can only be done by genotyping techniques. A total of 24 raw and treated sewage, surface and spring water samples were collected, concentrated and purified. DNA was extracted, and a nested PCR was used to amplify an 890 bp fragment of the gdh gene of G. duodenalis, which codes for glutamate dehydrogenase. Positive samples were cloned and sequenced. Ten out of 24 (41.6%) samples were confirmed to be positive for G. duodenalis by sequencing. Phylogenetic analysis grouped most sequences with G. duodenalis genotype AII from GenBank. Only two raw sewage samples presented sequences assigned to assemblage B. In one of these samples genotype AII was also detected. As these assemblages/genotypes are commonly associated to human giardiasis, the contact with these matrices represents risk for public health.

Cytochrome-b variation in Apis mellifera samples and its association with COI-COII patterns

Five Mbo I (Mbo-A, Mbo-M, Mbo-C(1), Mbo-C(2) and Mbo-C(3)) and Hinf I (Hinf-1 to Hinf-5) patterns were observed in Apis mellifera samples after restriction of a 485 bp fragment of the mitochondrial cytochrome-b (cyt-b) gene. Associating the cyt-b Restriction fragment length polymorphism (RFLP) pattern of each sample to its respective previously established COI-COII (Dra I sites) pattern, five restriction patterns (Mbo-C(1), Mbo-C(2), Mbo-C(3), Hinf-1 and Hinf-4) were observed in samples of maternal origin associated to the evolutionary branch C. No deletions or insertions were observed and the nucleotide substitution rate was estimated at 5.4%. Higher nucleotide diversity was observed among the branch C-haplotypes when compared with A and M lineages. Further studies are needed to confirm if the cyt-b + COI-COII haplotypes help to assign certain phylogeographic patterns to the branch C and to clarify phylogenetic relationships among A. mellifera subspecies.

Inspiration and mimesis in Plato's criticism of poetry

Plato criticizes poetry in several of his dialogues, beginning with Apology, his first work, and ending with Laws, his last. In these dialogues, his criticism of poetry can be divided into two streams: poetry is criticized for either being divinely inspired, or because it is mimetic or imitative of reality. However, of the dialogues which criticize poetry in these ways, it is not until Laws that Plato mentions both inspiration and mimesis together, and then it is only in a few sentences. Furthermore, nowhere in the dialogues does Plato discuss their relationship. This situation has a parallel in the secondary literature. While much work has been done on inspiration or mimesis in Plato’s criticism of poetry, very little work exists which discusses the connection between them. This study examines Plato’s treatment - in the six relevant dialogues - of these two poetic elements, inspiration and mimesis, and shows that a relationship exists between them. Both can be seen to relate to two important Socratic-Platonic concerns: the care of the soul and the welfare of the state. These concerns represent a synthesis of Socratic moral philosophy with Platonic political beliefs. In the ‘inspiration’ dialogues, Ion, Apology, Meno, Phaedrus and Laws, poetic inspiration can affect the Socratic exhortation which considers the care of the individual soul. Further, as we are told in Apology, Crito and Gorgias, it is the good man, the virtuous man - the one who cares for his soul - who also cares for the welfare of the state. Therefore, in its effect on the individual soul, poetic inspiration can also indirectly affect the state. In the ‘mimesis’ dialogues, Republic and Laws, this same exhortation, on the care of the soul, is posed, but it is has now been rendered into a more Platonic form - as either the principle of specialization - the ‘one man, one job’ creed of Republic, which advances the harmony between the three elements of the soul, or as the concord between reason and emotion in Laws. While in Republic, mimesis can damage the tripartite soul's delicate balance, in Laws, mimesis in poetry is used to promote the concord. Further, in both these dialogues, poetic mimesis can affect the welfare of the state. In Republic, Socrates notes that states arc but a product of the individuals of which they are composed Therefore, by affecting the harmony of the individual soul, mimesis can then undermine the harmony of the state, and an imperfect political system, such as a timarchy, an oligarchy, a democracy, or a tyranny, can result. However, in Laws, when it is harnessed by the philosophical lawgivers, mimesis can assist in the concord between the rulers and the ruled, thus serving the welfare of the state. Inspiration and mimesis can thus be seen to be related in their effect on the education of both the individual, in the care of the soul, and the state, in its welfare. Plato's criticism of poetry, therefore, which is centred on these two features, addresses common Platonic concerns: in education, politics, ethics, epistemology and psychology.

Facetime, and ; From soaps to sci-fi : the world of fandom

A novel and exegesis exploring identity, growing up and the cultural significance of television and B-grade horror films.

R&D investment, international trade, and home market and competitiveness efects

We analyze the effects of R&D investment on international trade. The importance of studying this comes from the fact that one of the most important characteristics of modern industrial organization is that firms try to influence market behavior through strategic variables as R&D. Moreover international competition between firms is, more and more, also centered in R&D competition (besides output and price competition). With this in mind, we develop an oligopolist reciprocal-markets model where firms engage in R&D investment to achieve future reductions in marginal costs. We find ‘home market effects’ at the level of R&D investment, i.e.: firms located in countries that host a higher share of skilled-labor perform higher levels of R&D investment. As consequence, firms in these countries are more competitive than firms in other countries, and as such they can penetrate more easily foreign markets. As result of this ‘competitiveness effect’, countries where these firms are located run trade surplus, while countries where firms perform lower levels of R&D investment incur in trade deficits.

Mortality of Bemisia tabaci biotype B (sternorrhyncha: aleyrodidae) adults by aliphatic and aromatic synthetic sucrose esters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of Impurity Profiles of Lipiblock (R) vs. Orlistat using HPLC and LC-MS/MS

Comparative HPLC-UV and LC-MS/MS studies of impurity profiles of a reference sample (Xenical (R), F. Hoffmann La Roche Ltd., Switzerland) vs. generic (Lipiblock (R), EMS Sigma Pharma, a generic drug) were carried out with ethanol extracts of commercial samples. The generic formulation contained higher levels of common impurities as well as a considerable number of impurities not found in the reference product. The detected impurity profile of Lipiblock (R) revealed that it most likely is based on fermentation. Since the effect of the impurities is unknown, at this point fully synthetic Xenical (R) appears to offer a better safety margin than Lipiblock (R) which, however, compares quite well to other generic formulations.