Dynamic coding of temporal luminance variation

The range of variation in environmental stimuli is much larger than the visual system can represent. It is therefore sensible for the system to adjust its responses to the momentary input statistics of the environment, such as when our pupils contract to limit the light entering the eye. Previous evidence indicates that the visual system increasingly centers responses on the mean of the visual input and scales responses to its variation during adaptation. To what degree does adaptation to a stimulus varying in luminance over time result in such adjustment of responses? The first two experiments were designed to test whether sensitivity to changes in the amplitude and the mean of a 9.6° central patch varying sinusoidally in luminance at 0.6 Hz would increase or decrease with adaptation. This was also tested for a dynamic peripheral stimulus (random patches rotating on the screen) to test to what extent the effects uncovered in the first two experiments reflect retinotopic mechanisms. Sensitivity to changes in mean and amplitude of the temporal luminance variation increased sharply the longer the adaptation to the variation, both for the large patch and the peripheral patches. Adaptation to luminance variation leads to increased sensitivity to temporal luminance variation for both central and peripheral presentation, the latter result ruling retinotopic mechanisms out as sole explanations for the adaptation effects.     

Inductive method for assessing the amount and orientation of steel fibers in concrete

Steel fibers are ferromagnetic and they have the property of altering the magnetic field around them. This paper discusses a method and gives a practical example to measure, non-destructively, the amount and orientation of fibers from cubic concrete specimens (150?mm). This is possible because the fibers affect inductance of a sensor (an inductive coil) that is wrapped around the specimen.     

Wireless sensor node localization

For most wireless sensor network (WSN) applications, the positions of the sensor nodes need to be known. Global positioning systems have not fitted into WSNs very well owing to their price, power consumption, accuracy and limitations in their operating environment. Hence, the last decade has brought about a large number of proposed methods for WSN node localization. They show tremendous variation in the physical phenomena they use, the signal properties they measure, the resources they consume, as well as in their accuracy, range, advantages and limitations. This paper provides a high-level, comprehensive overview of this very active research area.     

Analysis of laser scanning and strategies for dimensional and geometrical control

Noncontact scanning systems are becoming more present in the industry every day. These systems allow a significant reduction in manufacturing costs, mainly due to the important decrement in the inspection time. They enable obtaining a great amount of data that provides very good levels of quality in results. In spite of the well-known advantages that these systems offer, there are also some difficulties, such as the undefined and nonstandardized accuracy when compared with traditional inspection systems based on touch-trigger probes. That is one of the reasons for the practical absence of scanning systems in metrological applications: they have not been adequately tested in terms of accuracy for geometric and dimensional tolerance control. In fact, these systems are mainly used in reverse engineering or multimedia applications. The goal pursued in this research is to analyze the applicability of scanning systems for measuring and control of tolerances. Two different scanning systems were analyzed: a laser triangulation sensor and a touch-trigger probe, both mounted on a coordinate measuring machine. Several test parts were designed, which include different canonical features: planes, spheres, cylinders, holes (outer and inner), and conical surfaces. A common alignment method was defined in order to compare the geometry generated for both scanning systems. Different scanning orientation strategies were defined for laser scanning. Besides this, features were reconstructed with several computer-aided design systems, and the correlation between the contact and noncontact geometries was analyzed to study the convergence of results among them. Finally, an analysis was carried out to compare them in terms of geometrical and dimensional tolerances, considering the contact measurements as datum. As a result, some advises are given with respect to the best strategies for scanning, estimating the deviations.     

Functional Properties of Honey,Propolis, and Royal Jelly

ABSTRACT: Honey, propolis, and royal jelly, products originating in the beehive, are attractive ingredients for healthy foods. Honey has been used since ancient times as part of traditional medicine. Several aspects of this use indicate that it also has functions such as antibacterial, antioxidant, antitumor, anti‐inflamatory, antibrowning, and antiviral. Propolis is a resinous substance produced by honeybees. This substance has been used in folk medicine since ancient times, due to its many biological properties to possess, such as antitumor, antioxidant, antimicrobial, anti‐inflammatory, and immunomodulatory effects, among others. Royal jelly has been demonstrated to possess numerous functional properties such as antibacterial activity, anti‐inflammatory activity, vasodilative and hypotensive activities, disinfectant action, antioxidant activity, antihypercholesterolemic activity, and antitumor activity. Biological activities of honey, propolis, and royal jelly are mainly attributed to the phenolic compounds such as flavonoids. Flavonoids have been reported to exhibit a wide range of biological activities, including antibacterial, antiviral, anti‐inflammatory, antiallergic, and vasodilatory actions. In addition, flavonoids inhibit lipid peroxidation, platelet aggregation, capillary permeability and fragility, and the activity of enzyme systems including cyclo‐oxygenase and lipoxygenase.     

The effect of innovativeness on the adoption of B2C e-commerce: A model based on the Theory of Planned Behaviour

This paper analyses the factors that lead Internet users to becoming online shoppers. In particular, assuming that Internet is an innovation affecting the way individuals shop, a model of electronic commerce adoption is proposed that adds personal innovativeness to the traditional formulation of the Theory of Planned Behaviour. The theoretical model proposed is tested on a sample of Web users with no experience in online shopping. The results denote that electronic commerce acceptance is determined by attitudes to the system, subjective norm and personal innovativeness in the domain of information technology. Moreover, we find that personal innovativeness has a moderating effect on the acceptance of electronic commerce.     

THE COMPOSITION OF TWO SPANISH PEPPER VARIETIES (FRESNO DE LA VEGA AND BENAVENTE‐LOS VALLES) IN DIFFERENT RIPENING STAGES

ABSTRACT

The chemical composition of two traditional varieties of Spanish peppers, “Fresno de la Vega” and “Benavente‐Los Valles” harvested in the provinces of León and Zamora, respectively, at different ripening stages (green mature, breaker and red) were evaluated. Herein we report the global composition, mineral and trace element contents, and the most relevant physicochemical parameters of each variety of pepper collected in 2 consecutive years. Both pepper varieties showed a similar chemical composition, except in vitamin C content, which resulted to be about 70% higher in Fresno de la Vega peppers. Red ripe fruits were high in total carbohydrates, fructose, glucose, sucrose, fat (64.5, 29.14, 25.57, 2.94, 1.79/100 g dry weight, respectively) and total soluble solids (6.83°Brix). Ascorbic acid content also increased progressively during ripening, reaching a mean value of 1.81 mg/100 g dry weight for Fresno de la Vega peppers. Potassium was the most abundant of the analyzed elements in the all samples, followed by phosphorus, magnesium, calcium and sodium. The order of the levels of the trace elements was iron > manganese > zinc > copper.

PRACTICAL APPLICATIONS

This report underscores the potential value of two traditional varieties of Spanish peppers and provides information on their composition during ripening to decide the proper harvesting time, which can be useful in the food industry.     

n-Pentane Hydroisomerization on Pt Containing HZSM-5, HBEA and SAPO-11

Hydroisomerization of n-pentane over platinum promoted acids zeolites was studied. The effect of structure and acidity of the support was investigated at atmospheric pressure between 250 and 400 °C. Pt/HDBEA catalyst showed the best performance at 300 °C with high activity and selectivity to isopentane, due to its structure and a proper balance between acid and metallic sites. This catalyst has a high catalytic stability and regeneration under air flow after deactivation by coking, restores its activity and selectivity.