Importance Sampling for Objective Function Estimations in Neural Detector Training Driven by Genetic Algorithms

To train Neural Networks (NNs) in a supervised way, estimations of an objective function must be carried out. The value of this function decreases as the training progresses and so, the number of test observations necessary for an accurate estimation has to be increased. Consequently, the training computational cost is unaffordable for very low objective function value estimations, and the use of Importance Sampling (IS) techniques becomes convenient. The study of three different objective functions is considered, which implies the proposal of estimators of the objective function using IS techniques: the Mean-Square error, the Cross Entropy error and the Misclassification error criteria. The values of these functions are estimated by IS techniques, and the results are used to train NNs by the application of Genetic Algorithms. Results for a binary detection in Gaussian noise are provided. These results show the evolution of the parameters during the training and the performances of the proposed detectors in terms of error probability and Receiver Operating Characteristics curves. At the end of the study, the obtained results justify the convenience of using IS in the training.     

Preserved monitoring and control processes in temporal lobe epilepsy.

Objective: The aim of this study was to assess an aspect of metamemory never examined before in patients with temporal lobe epilepsy (TLE): the ability to upgrade the accuracy of one's memory predictions after study. Method: Four lists of different levels of difficulty and relatedness were presented to 15 TLE patients and 15 control participants, who were asked to predict their subsequent recall both before and after studying each list. Results: The results showed clear impairment in recall in TLE patients. However, both TLE patients and controls showed an improvement in accuracy in their poststudy predictions compared with their prestudy predictions, showing that both groups were able to upgrade their metamemory predictions. Unexpectedly, prediction accuracy was overall higher in TLE patients than in controls. Moreover, study time was allocated in both groups taking into account the characteristics of the list. Conclusion: These results confirm and extend findings of Howard et al. (2010) of intact metamemory in TLE patients, and provide further support to the dissociation between memory and metamemory in this clinical population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of cooking and germination on phenolic composition and biological properties of dark beans (Phaseolus vulgaris L.)

Legumes are the base´s diet in several countries. They hold a high nutritional value, but other properties related to human health are nowadays being studied. The aim of this work was to study the influence of processes (boiling or germination) on the phenolic composition of dark beans (Phaseolus vulgaris L. c.v. Tolosana) and their effect on their antioxidant, neuroprotective and anticancer ability. Phenolic composition of raw and processed dark beans was analysed by HPLC-PAD and HPLC–ESI/MS. The antioxidant activity was evaluated by ORAC. Astrocytes cultures (U-373) have been used to test their neuroprotective effect. Anticancer activities were evaluated on three different cell lines (renal adenocarcinoma (TK-10), breast adenocarcinoma (MCF-7) and melanoma (UACC-62)) by sulphorhodamine B method. Qualitative and quantitative differences in phenolic composition have been observed between raw and processed dark beans that influence the antioxidant activity, mainly for germinated samples which show a decrease of antioxidant capacity. Although every assayed extracts decreased reactive oxygen species release and exhibited cytotoxicity activities on cancer cell lines, raw beans proved to be the most active in neuroprotective and antitumoral effects; this sample is especially rich in phenolic compounds, mainly anthocyanins. This study further demonstrated that phenolic composition of dark beans is related with cooking process and so with their neuroprotective and anticancer activity; cooking of dark beans improves their digestion and absorption at intestinal level, while maintaining its protective ability on oxidative process at cellular level.     

An experimental and theoretical study of the carbazole to carbazole intramolecular energy transfer in N‐vinylcarbazole/vinyl tert‐butyl‐benzoate copolymers of different molar compositions

Fluorescence depolarization and quenching measurements of N‐vinyl carbazole/vinyl tert‐butyl‐benzoate copolymers in dilute solution of several fluid solvents and in a rigid poly(methyl methacrylate) matrix were performed to study the effect of copolymer composition on the intramolecular energy transfer (IET) between carbazole groups (Cz) along the polymer chain. IET efficiency, as the amount of Cz? Cz intramolecular excimer formation, monotonically increases with Cz content up to a number average sequence length of carbazole of ca 12 (Cz molar content ≥ 90%). After this value, IET efficiency remains almost constant. Molecular dynamics simulations on isotactic and syndiotactic copolymer fragments of several monomer compositions were used for obtaining different parameters related to the efficiency for the IET process between Cz units along the polymer chain. Copyright © 2011 Society of Chemical Industry     

Magnitude and Significance in Landscape Change

Landscape is organised in mosaics: sets of patches with a defined pattern of boundaries through which patches interact. Changes in patches cause changes in mosaics. Landscape change has two components: a quantitative one, referring to the areas in which changes happen, and a qualitative one, referring to the degree of similarity among the mosaics substituting each other. The quantitative component informs on the magnitude of the change: the total area in which landscape mosaics have changed; the qualitative one informs on the significance thereof: the ecological differences between the mosaics substituting each other. This paper presents an index for quantifying landscape change and for discriminating between magnitude and significance therein. It was tested by study of changes in the landscape mosaics in Madrid, Spain. Results show that the index developed is useful for this purpose. This enables objective comparison of different landscape changes presenting different combinations of magnitude and significance.     

Neuroprotective properties of Spanish red wine and its isolated polyphenols on astrocytes

The neuroprotective effect of Merlot red wine and its isolated polyphenols was evaluated in an oxidative stress model induced by Fenton reaction and hydrogen peroxide in the human astrocytoma U373 MG cell line. Compared with cells treated only with oxidative stress inductors, the pre-incubation with Merlot red wine for 24 h caused a significant increase in cell viability for all concentrations assayed. The most abundant polyphenols found in Merlot red wine were the flavonoids catechin (37.8 mg/l), epicatechin (52.3 mg/l), quercetin (5.89 mg/l) and procyanidins (15.2 mg/l), the hydroxybenzoic acid gallic acid (16.7 mg/l), and the phenolic alcohol tyrosol (31.4 mg/l). The potential protective role of these polyphenols when isolated was then assessed in treated Fenton reaction U373 MG cells. Polyphenols decreased reactive oxygen species generation and increased the activity and the protein expression of the antioxidant enzymes catalase, superoxide dismutase, glutathione reductase and glutathione peroxidase. Of the polyphenols, quercetin and procyanidins showed the highest neuroprotective effect.     

Evaluation of the chemical composition and antimicrobial activity of Mentha pulegium,Juniperus phoenicea,and Cyperus longus essential oils from Morocco

The present study evaluates the chemical composition and antimicrobial activity of the essential oils (EOs) of Mentha pulegium L., Juniperus phoenicea L. and Cyperus longus L. from Morocco. The composition of these species was analyzed by GC/MS and 84 components were identified. M. pulegium EO showed a great similarity with EOs coming from other regions, as pulegone, the major component, accounted for about 70% of the EO. The EO of J. phoenicea had as main components α-pinene (24.9%), β-phellandrene (24.4%) and α-terpinyl acetate (12.9%). The EO extracted from C. longus was remarkably rich in sesquiterpene hydrocarbons (83.2%), which included β-himachalene (46.6%), α-humulene (16.9%), and γ-himachalene (10.1%). The antimicrobial activity of these EOs has been evaluated against seven bacteria of significant importance for food hygiene. According to the results, M. pulegium showed the best bacteriostatic and bactericidal effect, followed by J. phoenicea and C. longus. So far as we know, this is the first report on the quantitative composition and biological activity of the essential oil from C. longus. The tested EOs showed a variable degree of antimicrobial activity being M. pulegium the most effective one.     

Hf-based Metal-Organic Frameworks in Heterogeneous Catalysis

Among the large family of metal-organic frameworks (MOFs), Hf-based MOFs are foreseen as promising materials for practical applications due to their exceptional characteristics such as rich structure versatility and outstanding stability. This review discusses catalytic applications of Hf-MOFs since their development in 2012, and are summarized according to the location of the active site: at the hafnium node, at the linker or as a single-site chemical entity located at the hafnium node after post-synthetic functionalization. Special emphasis is made to synthetic preparation methods and catalytic performance.     

Influence of frozen storage on aptitude of sardine and dolphinfish for cold-smoking process

Stability of dolphinfish (Coryphaena hippurus) and sardines (Sardina pilchardus) of different fat content (lean and fatty sardines) during frozen storage and its suitability for cold-smoking throughout storage were evaluated in order to overcome seasonal and excess catches of these species. Dolphinfish showed a relative stability regarding protein functionality (protein solubility, apparent viscosity, water and lipid holding capacity), lipid oxidation and total volatile basic nitrogen (TVBN) accumulation, which led to high acceptability ratings of the resulting smoked product throughout frozen storage (340 days). However, both lean and fatty sardines showed a marked loss of protein functionality, which coincided with the accumulation of oxidation products and TVBN. Freezing of raw muscle may become a valuable preservation method for the smoking industry to overcome the short caught period of dolphinfish in the Balearic Islands and to make use of excess catches of both, lean and fatty sardine. High quality smoked products may be obtained from the frozen muscle during approximately twelve, four and two months of frozen storage for Dolphinfish, lean and fatty sardine, respectively.     

Using Structural Equation Modeling (SEM) for the Study of Impurity Profiles of Drug Substances

The impurity profile is one of the most important quality characteristics of a drug substance. Although it is always desirable to determine the chemical structure of all impurities forming the impurity profile, unfortunately this is not always economically and technically feasible because of the extremely low concentrations at which some impurities may be found in the drug substance. Therefore, alternative approaches to the chemical analysis are needed for trying to determine the origin of the unidentified impurities.

In a previous study conducted by our group, based on exploratory (principal component and hierarchical cluster) analysis, we were able to suggest a hypothesis for explaining the origin of the unidentified impurities of a drug substance. However, there was still a concern that alternative hypotheses might explain the same phenomenon equally well. This article explores the application of recent developments in structural equation modeling for the systematic generation and selection of hypotheses (models) worthy of being confirmed by chemical research.