Naltrexone, naltrindole, and CTOP block cocaine-induced sensitization to seizures and death

I.c.v. injection for 9 days of either naltexone (NTX) (5, 10, 20, 40 micrograms/rat) or a selective mu peptide (CTOP) (0.125, 0.25, 0.5, 1, 3, 6 micrograms/rat) or delta (naltrindole) (NLT) (5, 10, 20 micrograms/rat) subtype opioid receptor antagonist affected sensitization to cocaine (COC) (50 mg/kg, i.p.) administered 10 min after. NTX (5 and 40 micrograms/rat), NLT (10 and 20 micrograms/rat), and the peptide CTOP (0.25-0.5 microgram/rat) attenuated seizure parameters (percent of animals showing seizures, mean score and latency) in a day-related manner. The DD50 (days to reach 50% of death) value for COC was 2.69, whereas it was 9.67 and 7.27 for NTX 5 and 40 micrograms/rat, 8.59 for NLT (10 micrograms/rat), and 6.11, 5.95, and 4.30 for CTOP (0.25, 0.5, and 1 microgram/rat respectively). These findings suggest a concurrent involvement of mu- and delta-opioid receptor subtype in COC-induced sensitization to toxic effects.     

On the problem of local minima in recurrent neural networks

Many researchers have recently focused their efforts on devising efficient algorithms, mainly based on optimization schemes, for learning the weights of recurrent neural networks. As in the case of feedforward networks, however, these learning algorithms may get stuck in local minima during gradient descent, thus discovering sub-optimal solutions. This paper analyses the problem of optimal learning in recurrent networks by proposing conditions that guarantee local minima free error surfaces. An example is given that also shows the constructive role of the proposed theory in designing networks suitable for solving a given task. Moreover, a formal relationship between recurrent and static feedforward networks is established such that the examples of local minima for feedforward networks already known in the literature can be associated with analogous ones in recurrent networks.     

Forecast of oil price and consumption in the short term under three scenarios: Parabolic,linear and chaotic behaviour

The paper examines the evolution of price and consumption of oil in the last decades to construct a relationship between them. Then the work considers three possible scenarios of oil price: parabolic, linear and chaotic behaviour, to predict the evolution of price and consumption of oil up to December 2003.     

Processing directed acyclic graphs with recursive neural networks

Recursive neural networks are conceived for processing graphs and extend the well-known recurrent model for processing sequences. In Frasconi et al. (1998), recursive neural networks can deal only with directed ordered acyclic graphs (DOAGs), in which the children of any given node are ordered. While this assumption is reasonable in some applications, it introduces unnecessary constraints in others. In this paper, it is shown that the constraint on the ordering can be relaxed by using an appropriate weight sharing, that guarantees the independence of the network output with respect to the permutations of the arcs leaving from each node. The method can be used with graphs having low connectivity and, in particular, few outcoming arcs. Some theoretical properties of the proposed architecture are given. They guarantee that the approximation capabilities are maintained, despite the weight sharing.     

Automatic document classification and indexing in high-volume applications

In this paper a system for analysis and automatic indexing of imaged documents for high-volume applications is described. This system, named STRETCH (STorage and RETrieval by Content of imaged documents), is based on an Archiving and Retrieval Engine, which overcomes the bottleneck of document profiling bypassing some limitations of existing pre-defined indexing schemes. The engine exploits a structured document representation and can activate appropriate methods to characterise and automatically index heterogeneous documents with variable layout. The originality of STRETCH lies principally in the possibility for unskilled users to define the indexes relevant to the document domains of their interest by simply presenting visual examples and applying reliable automatic information extraction methods (document classification, flexible reading strategies) to index the documents automatically, thus creating archives as desired. STRETCH offers ease of use and application programming and the ability to dynamically adapt to new types of documents. The system has been tested in two applications in particular, one concerning passive invoices and the other bank documents. In these applications, several classes of documents are involved. The indexing strategy first automatically classifies the document, thus avoiding pre-sorting, then locates and reads the information pertaining to the specific document class. Experimental results are encouraging overall; in particular, document classification results fulfill the requirements of high-volume application. Integration into production lines is under execution. Received March 30, 2000 / Revised June 26, 2001     

Encoding nondeterministic fuzzy tree automata into recursive neural networks

Fuzzy neural systems have been a subject of great interest in the last few years, due to their abilities to facilitate the exchange of information between symbolic and subsymbolic domains. However, the models in the literature are not able to deal with structured organization of information, that is typically required by symbolic processing. In many application domains, the patterns are not only structured, but a fuzziness degree is attached to each subsymbolic pattern primitive. The purpose of this paper is to show how recursive neural networks, properly conceived for dealing with structured information, can represent nondeterministic fuzzy frontier-to-root tree automata. Whereas available prior knowledge expressed in terms of fuzzy state transition rules are injected into a recursive network, unknown rules are supposed to be filled in by data-driven learning. We also prove the stability of the encoding algorithm, extending previous results on the injection of fuzzy finite-state dynamics in high-order recurrent networks.     

Photochemical properties of sintered iron (III) oxide

The photochemical properties of vacuum deposited films and of sintered and doped iron(III) oxide have been studied. From the wavelength dependence of the photopotentials we know that photo-activity of the electrochemical cell with the iodine/iodide redox couple starts at the same wavelength, 600–650 nm, as the absorption of light and the photoconductivity of vacuum deposited films. Open circuit potentials of about 400 mV have been observed with the visible radiation from a 150 W xenon lamp. In neutral solution photocorrosion was too small to be observed.     

Evaluation of the spatial coherence of a light beam through transverse intensity measurements

The problem of recovering the coherence features of a partially coherent quasi-monochromatic scalar optical source, starting solely from intensity measurements on the emitted beam, is addressed in the most general way, under the paraxial approximation. In particular, it is shown that on expanding the beam emitted by the source as a bundle of partially correlated Hermite-Gaussian beams, the correlation coefficients can be recovered, in principle, simply by performing scalar products between transverse intensity distributions and suitably defined functions.     

Dolichol levels in younger and older rat hearts heterotopically transplanted in younger recipients

Dolichol (D) levels increase dramatically in older tissue. An understanding of the exchangeability of D between tissues may be essential in order to understand the mechanism of the abnormal accumulation associated with aging. The question was investigated by the use of organ transplantation. D-poor hearts donated by 3-mon-old and D-rich by 22-mon-old male Lewis rats were transplanted heterotopically in 3-mon-old syngenic recipients, whose peripheral tissues and liver were poor in D. Native and transplanted hearts were taken 7 and 21 d after surgery. Native hearts of 3-mon- and 22-mon-old male Lewis rats served as control. D concentration and quantity were higher in older than in younger native hearts as expected. In the transplanted hearts, the quantity of D was unchanged, irrespective of the age of the donor and of the time of transplantation, whereas D concentration increased because of the remarkable disuse atrophy. No changes in D were observed in recipients’ tissues. It is concluded that dolichol is not redistributed via circulation from the transplanted heart to the tissues and liver of the younger recipient.     

A unified probabilistic framework for Web page scoring systems

The definition of efficient page ranking algorithms is becoming an important issue in the design of the query interface of Web search engines. Information flooding is a common experience especially when broad topic queries are issued. Queries containing only one or two keywords usually match a huge number of documents, while users can only afford to visit the first positions of the returned list, which do not necessarily refer to the most appropriate answers. Some successful approaches to page ranking in a hyperlinked environment, like the Web, are based on link analysis. We propose a general probabilistic framework for Web page scoring systems (WPSS), which incorporates and extends many of the relevant models proposed in the literature. In particular, we introduce scoring systems for both generic (horizontal) and focused (vertical) search engines. Whereas horizontal scoring algorithms are only based on the topology of the Web graph, vertical ranking also takes the page contents into account and are the base for focused and user adapted search interfaces. Experimental results are reported to show the properties of some of the proposed scoring systems with special emphasis on vertical search.