New determination of zonal harmonics coeffi- cients of the earth's gravitational potential special report no. 165

Zonal harmonics coefficient determination of earth gravitational potentia

Long term variation of the solar diurnal anisotropy of galactic cosmic rays observed with the Nagoya multi-directional muon detector

We analyze the three dimensional anisotropy of the galactic cosmic ray (GCR) intensities observed independently with a muon detector at Nagoya in Japan and neutron monitors over four solar activity cycles. We clearly see the phase of the free-space diurnal anisotropy shifting toward earlier hours around solar activity minima in A>0 epochs, due to the reduced anisotropy component parallel to the mean magnetic field. The average parallel component is consistent with a rigidity independent spectrum, while the perpendicular component increases with GCR rigidity. We suggest that this harder spectrum of the perpendicular component is due to contribution from the drift streaming. We find that the bidirectional latitudinal density gradient is positive in A>0 epoch, while it is negative in A<0 epoch, in accord with the drift model prediction. The radial density gradient, on the other hand, varies with ~11-year cycle with maxima (minima) in solar maximum (minimum) periods, but there is no significant difference seen between average radial gradients in A>0 and A<0 epochs. The average parallel mean free path is larger in A0. We also find, however, that parallel mean free path (radial gradient) appears to persistently increase (decreasing) in the last three cycles of weakening solar activity. We suggest that simple differences between these parameters in A>0 and A<0 epochs are seriously biased by these long-term trends.Comment: accepted for the publication in the Astrophysical Journa

Infant and child oral health risk status correlated to behavioral habits of parents or caregivers: a survey in central Italy

Aim: The aim of this survey was to evaluate the knowledge and awareness of parents and caregivers about potential oral health risk factors for their children in their first months of life (3–30 months). Materials and Methods: The participation to the survey was proposed to all parents or caregivers of children attending the public consulting service in Latina for mandatory vaccinations during the period of June to August 2014. A self-administered questionnaire was completed to obtain information regarding demographic variables, infant feeding practice, maternal oral health during and after pregnancy, children’s oral hygiene habits and risk behaviors (e.g., sharing cutlery, tasting of baby food, nightly using of baby bottles with sugared beverages, or sugared pacifier), and knowledge about caries and its transmission. The analysis of the data was performed using SPSS 14.0 for Windows (SPSS Inc., Chicago, IL, USA). The variance analysis and chi-square test were used to investigate the relationship between the variables. Results: Overall, the parents of 304 children consented to fill the questionnaire. Data analysis showed that about 50% of respondents considered dental caries an infectious disease, however, 53.6% was not aware of the potential vertical transmissibility of cariogenic bacteria through contaminated saliva. It is a common trend in the early stages of weaning to taste the baby food (53%) and sharing cutlery (38.5%). With regard to children oral health care, parents reported no toothbrushing for 53.1% of the children in their first 3 years of life. The relationship between the two variables concerning caries transmissibility and tools sharing carried out on through Pearson chi-square test identified P = 0.32. Conclusions: From this survey, the need for parental oral health promoting program emerged to control children oral health risk status

Multiagent Maximum Coverage Problems: The Trade-off Between Anarchy and Stability

The price of anarchy and price of stability are three well-studied performance metrics that seek to characterize the inefficiency of equilibria in distributed systems. The distinction between these two performance metrics centers on the equilibria that they focus on: the price of anarchy characterizes the quality of the worst-performing equilibria, while the price of stability characterizes the quality of the best-performing equilibria. While much of the literature focuses on these metrics from an analysis perspective, in this work we consider these performance metrics from a design perspective. Specifically, we focus on the setting where a system operator is tasked with designing local utility functions to optimize these performance metrics in a class of games termed covering games. Our main result characterizes a fundamental trade-off between the price of anarchy and price of stability in the form of a fully explicit Pareto frontier. Within this setup, optimizing the price of anarchy comes directly at the expense of the price of stability (and vice versa). Our second results demonstrates how a system-operator could incorporate an additional piece of system-level information into the design of the agents' utility functions to breach these limitations and improve the system's performance. This valuable piece of system-level information pertains to the performance of worst performing agent in the system.Comment: 14 pages, 4 figure

Evaluation of Offshore Wind Energy Resource in Chinese Coastal Sea Using QuikSCAT Data

textabstractThis paper analytically derives conditions under which the slope of the tax-reaction function is negative in a classical tax competition model. If countries maximize welfare, a negative slope (reflecting strategic substitutability) occurs under relatively mild conditions. The strategic tax response is crucial for understanding tax competition games, as well as the welfare effects of partial tax unions (whereby a subset of countries coordinate their tax rates). Indeed, contrary to earlier findings that have assumed strategic complementarity in tax rates, we show that partial tax unions might reduce welfare under strategic substitutability