Investigating the mobility habits of electric bike owners through GPS data

This paper investigates the mobility habits of electric bike owners as well as their preferred routes. Through a GPS tracking campaign conducted in the city of Ghent (Belgium) we analyze the mobility habits (travel distance, time spent, speed) during the week of some e-bike users. Moreover, we propose the results of our map matching, based on the Hausdorff criterion, and preliminary results on the route choice of our sample. We strongly believe that investigating the behavior of electric bikes’ owners can help us in better understanding how to incentivize the use of this mode of transport. First results show that the trips with a higher travel distance are performed during the working days. It could be easily correlated with the daily commuting trips (home-work). Moreover, the results of our map-matching highlight how 61% of the trips are performed using the shortest path

Measuring infection transmission in a stochastic SIV model with infection reintroduction and imperfect vaccine

An additional compartment of vaccinated individuals is considered in a SIS stochastic epidemic model with infection reintroduction. The quantification of the spread of the disease is modeled by a continuous time Markov chain. A well-known measure of the initial transmission potential is the basic reproduction number $R_0$, which determines the herd immunity threshold or the critical proportion of immune individuals required to stop the spread of a disease when a vaccine offers a complete protection. Due to repeated contacts between the typical infective and previously infected individuals, $R_0$ overestimates the average number of secondary infections and leads to, perhaps unnecessary, high immunization coverage. Assuming that the vaccine is imperfect, alternative measures to $R_0$ are defined in order to study the influence of the initial coverage and vaccine efficacy on the transmission of the epidemic

Measuring infection transmission in a stochastic SIV model with infection reintroduction and imperfect vaccine

An additional compartment of vaccinated individuals is considered in a SIS stochastic epidemic model with infection reintroduction. The quantification of the spread of the disease is modeled by a continuous time Markov chain. A well-known measure of the initial transmission potential is the basic reproduction number $R_0$, which determines the herd immunity threshold or the critical proportion of immune individuals required to stop the spread of a disease when a vaccine offers a complete protection. Due to repeated contacts between the typical infective and previously infected individuals, $R_0$ overestimates the average number of secondary infections and leads to, perhaps unnecessary, high immunization coverage. Assuming that the vaccine is imperfect, alternative measures to $R_0$ are defined in order to study the influence of the initial coverage and vaccine efficacy on the transmission of the epidemic

Casting and Mechanized Titanium Restorations

INTRODUCTION: New materials and methods for clinical dentistry are continuously being introduced. There is a growing interest in the use of titanium as a restorative material for several reasons: its relatively low cost, favorable physical properties and biocompatibility. However, titanium is technically more difficult to handle than conventional metal alloys. There are two fabrication methods for titanium restorations: casting and mechanized (a combination of machine duplication and spark erosion-Pro- -cera method). PURPOSE: The aim of this review was to evaluate the advantages and disadvantages of the two fabrication methods used for titanium restorations and to make some recommendations on the indications. MATERIAL AND METHODS: Dental literature was reviewed including clinical and technique articles on the use of titanium in prosthodontic restorations. RESULT: The use of mechanized titanium has more restrictive indications than casting, but assures better marginal fit of the restorations. The bond strength of porcelain fused to titanium is questioned, because of the lower rigidity of titanium than conventional alloys and discrepancies in the thermal expansion coefficient between titanium and ceramic. Thus, low fusing ceramics tend to predominate today. The esthetic result varies. Furthermore titanium restorations require a qualified dental technician. CONCLUSION: It can be concluded that titanium is a promising alternative for prosthodontic restorations. Several error sources associated with casting can be eliminated with mechanized titanium restorations. However, little information is availableon the clinical performance of titanium restorations. More clinical prospective studies are necessary before titanium can be recommended for general clinical use

Observations of I2 at a remote marine site

Inorganic iodine plays a significant role in the photochemistry of the marine boundary layer, but the sources and cycling of iodine are not well understood. We report the first I2 observations in marine air that is not impacted by coastal macroalgal emissions or sea ice chemistry. The data clearly demonstrate that the very high I2 levels previously reported for coastal air are not representative of open ocean conditions. In this study, gas phase I2 was measured at the Cape Verde Atmospheric Observatory, a semi-remote site in the eastern tropical Atlantic, using atmospheric pressure chemical ionization tandem mass spectrometry. Atmospheric I2 levels typically increased beginning at sunset, leveled off after midnight, and then rapidly decreased at sunrise. There was also a smaller midday maximum in I 2 that was probably caused by a measurement artifact. Ambient I 2 mixing ratios ranged from <0.02-0.6 pmol mol-1 in May 2007 and <0.03-1.67 pmol mol-1 in May 2009. The sea-air flux implied by the nighttime buildup of I2 is too small to explain the observed daytime IO levels at this site. Iodocarbon measurements made in this region previously are also insufficient to explain the observed 1-2 pmol mol-1 of daytime IO. The observations imply the existence of an unknown daytime source of gas phase inorganic iodine. Carpenter et al. (2013) recently proposed that sea surface emissions of HOI are several times larger than the flux of I2. Such a flux could account for both the nighttime I2 and the daytime IO observations

On First-Passage Times and Sojourn Times in Finite QBD Processes and Their Applications in Epidemics

In this paper, we revisit level-dependent quasi-birth-death processes with finitely many possible values of the level and phase variables by complementing the work of Gaver, Jacobs, and Latouche (Adv. Appl. Probab. 1984), where the emphasis is upon obtaining numerical methods for evaluating stationary probabilities and moments of first-passage times to higher and lower levels. We provide a matrix-analytic scheme for numerically computing hitting probabilities, the number of upcrossings, sojourn time analysis, and the random area under the level trajectory. Our algorithmic solution is inspired from Gaussian elimination, which is applicable in all our descriptors since the underlying rate matrices have a block-structured form. Using the results obtained, numerical examples are given in the context of varicella-zoster virus infections

Analysis of the resolution of split-ring metamaterial lenses with application in parallel magnetic resonance imaging

In this work, we experimentally determine the resolution of split-ring metamaterials lenses with emphasis in magnetic resonance imaging applications. Two small sources are used to determine the minimal resolution of the lens, which is compared with previous theoretical predictions. Taking into account this minimal resolution, a second experiment is designed in order to study the ability of a split-ring lens to improve the localization of the field produced by two closely spaced coils. This ability could find application in parallel magnetic resonance imaging, which take advantage of the distinct coil sensitivities in order to reduce the image acquisition time. © 2011 American Institute of Physics

Secondhand Smoke Exposure in Hospitality Venues in Europe

BACKGROUND: Although in the last few years some European countries have implemented smoking bans in hospitality venues, the levels of secondhand smoke (SHS) in this occupational sector Could still be extremely high in most countries. OBJECTIVE: The aim of this study, was to assess exposure to SHS in hospitality venues in 10 European cities. METHODS: We included 167 hospitality venues (58 discotheques and pubs, 82 restaurants and cafeterias, and 27 fast-food restaurants) in this cross-sectional study. We carried Out fieldwork in 10 European cities: Vienna (Austria), Paris (France), Athens (Greece), Florence and Belluno (Italy), Galway (Ireland), Barcelona (Spain), Warsaw and Lublin (Poland), and Bratislava (Slovak Republic). We measured vapor-phase nicotine as an SHS marker. RESULTS: We analyzed 504 samples and found nicotine in most samples (97.4%). We found the highest median concentrations in discos/pubs [32.99 mu g/m(3); interquartile range (IQR), 8.06-66.84 mu g/m(3)] and lower median concentrations in restaurants/cafeterias (2.09 mu g/m(3); IQR, 0.49-6.73 mu g/m(3)) and fast-food restaurants (0.31 mu g/m(3); IQR, 0.11-1.30 mu g/m(3)) (p < 0.05). We found differences of exposure between countries that may be related to their smoking regulations. Where we sampled smoking and nonsmoking areas, nicotine concentrations were significantly lower in nonsmoking areas. CONCLUSIONS: Hospitality venues from European cities without smoking regulations have very high levels of SHS exposure. Monitoring of SHS on a regular basis as well as a total smoking ban in hospitality sector would be needed