Inertial sensors for smartphones navigation.

The advent of smartphones and tablets, means that we can constantly get information on our current geographical location. These devices include not only GPS/GNSS chipsets but also mass-market inertial platforms that can be used to plan activities, share locations on social networks, and also to perform positioning in indoor and outdoor scenarios. This paper shows the performance of smartphones and their inertial sensors in terms of gaining information about the user's current geographical locatio n considering an indoor navigation scenario. Tests were carried out to determine the accuracy and precision obtainable with internal and external sensors. In terms of the attitude and drift estimation with an updating interval equal to 1 s, 2D accuracies of about 15 cm were obtained with the images. Residual benefits were also obtained, however, for large intervals, e.g. 2 and 5 s, where the accuracies decreased to 50 cm and 2.2 m, respectively.

Failure of aminophylline and salbutamol to improve respiratory muscle function and exercise tolerance in healthy humans.

We investigated the effects of intravenously administered aminophylline (A; 6 mg/kg over 20 min, followed by 0.9 mg/kg/h), salbutamol (S; 4 micrograms/kg over 20 min, followed by 3 micrograms/kg/h) and placebo (P; saline solution) on the strength of the respiratory muscles, the ventilatory endurance and the exercise tolerance in 7 healthy humans. Neither A nor S caused bronchodilation, as shown by the lack of change in FEV1. The strength of respiratory muscles, as measured by maximal inspiratory pressure (MIP), and the ventilatory endurance, as measured by sustainable inspiratory pressure (SIP), were not statistically different after A (MIP: 136.5 +/- SE 11.6 cm H2O; SIP: 104.2 +/- 8.4 cm H2O or after S (MIP: 135.7 +/- 11.5; SIP: 107.1 +/- 10.4) compared to after P (MIP: 127.1 +/- 10.1; SIP: 105.0 +/- 5.9). Significant changes in 12-min walking distance, perceived exertion rate, anaerobic threshold, maximal work output, maximal O2 uptake were observed neither after A nor after S. The exchange ratio and heart rate were higher after A and S than after P at some steps of a progressive, symptom-limited, treadmill-based exercise test. This might be the result of metabolic or cardiovascular adaptations elicited by these drugs. We conclude that A or S at therapeutic concentrations have no clinically relevant beneficial effects on ventilatory muscle function and exercise tolerance in healthy subjects.