No abstract

a b s t r a c tThis study aimed to investigate the effects of chitosan on dry matter intake (DMI), nutrient digestibility, ruminal fermentation, and blood metabolites in Nellore steers. Eight ruminally cannulated Nellore steers (540 ± 28.5 kg of BW) were used in a replicated 4 × 4 Latin square design, with 21-d of experimental periods. The animals were randomly assigned to the following treatments: control (without chitosan addition; Q0), Q50, Q100 and Q150, by dosing 50, 100 and 150 mg/kg BW chitosan, respectively, through the cannula. Although there was no difference on DMI, chitosan addition increased dry matter, neutral detergent fiber, and crude protein apparent total-tract digestibility (P < 0.05). Ruminal pH was not affected, whereas NH 3 N concentration was quadratically affected with chitosan addition (P = 0.01). There were no differences in total volatile fatty acids concentration among treatments. Chitosan had a quadratic effect on propionate and butyrate, whereas acetate molar proportions decreased linearly (P < 0.05). Acetate:propionate ratio decreased with chitosan addition (P < 0.05). Plasma glucose concentration was higher with chitosan addition (P < 0.05); however, total protein, urea, aspartate aminotransferase, and gamma-glutamyl transferase were not affected by chitosan. Addition of chitosan altered ruminal fermentation, improved nutrient digestibility, and did not appear to damage animal health.

Over the last decades, the development of navigation devices capable of guiding the blind through indoor and/or outdoor scenarios has remained a challenge. In this context, this paper’s objective is to provide an updated, holistic view of this research, in order to enable developers to exploit the different aspects of its multidisciplinary nature. To that end, previous solutions will be briefly described and analyzed from a historical perspective, from the first “Electronic Travel Aids” and early research on sensory substitution or indoor/outdoor positioning, to recent systems based on artificial vision. Thereafter, user-centered design fundamentals are addressed, including the main points of criticism of previous approaches. Finally, several technological achievements are highlighted as they could underpin future feasible designs. In line with this, smartphones and wearables with built-in cameras will then be indicated as potentially feasible options with which to support state-of-art computer vision solutions, thus allowing for both the positioning and monitoring of the user’s surrounding area. These functionalities could then be further boosted by means of remote resources, leading to cloud computing schemas or even remote sensing via urban infrastructure.

Abstract-Structural health monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of structures. Wireless networks (WNs) have been used to avoid the high cost of traditional generic wired systems. The most important limitation of SHM wireless systems is timesynchronization accuracy, scalability, and reliability. A complete wireless system for structural identification under environmental load is designed, implemented, deployed, and tested on three different real bridges. Our contribution ranges from the hardware to the graphical front end. System goal is to avoid the main limitations of WNs for SHM particularly in regard to reliability, scalability, and synchronization. We reduce spatial jitter to 125 ns, far below the 120 /xs required for high-precision acquisition systems and much better than the 10-/xs current solutions, without adding complexity. The system is scalable to a large number of nodes to allow for dense sensor coverage of real-world structures, only limited by a compromise between measurement length and mandatory time to obtain the final result. The system addresses a myriad of problems encountered in a real deployment under difficult conditions, rather than a simulation or laboratory test bed.

A wildland fire is an uncontrolled fire that occurs mainly in forest areas, although it can also invade urban or agricultural areas. Among the main causes of wildfires, human factors, either intentional or accidental, are the most usual ones. The number and impact of forest fires are expected to grow as a consequence of the global warming. In order to fight against these disasters, it is necessary to adopt a comprehensive, multifaceted approach that enables a continuous situational awareness and instant responsiveness. This paper describes a hierarchical wireless sensor network aimed atearly fire detection in risky areas, integrated with the fire fighting command centres, geographical information systems, and fire simulators. This configuration has been successfully tested in two fire simulations involving all the key players in fire fighting operations: fire brigades, communication systems, and aerial, coordination, and land means.