The Europa Ocean Discovery mission

Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`s surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges

Er-doped Tellurite glasses for planar waveguide power amplifier with extended gain bandwidth

Tellurite glass compositions doped with erbium and erbium/ytterbium optimised to support extended gain bandwidth with significant amplification have been fabricated, and their thermal, optical absorption, excitation and luminescence properties investigated. Each rare-earth dopant concentration was set at 1x1020/cm3. Broad emission cross-section bandwidths up to 50nm FWHM were observed, with fluorescence lifetimes of ~3ms. Collinear pump probe measurements on ~4mm thick bulk samples revealed peak gains of up to 2.1dB/cm at a wavelength of 1535nm in the co-doped material, with an incident pump intensity of only Iinc~8kW/cm2 at a wavelength of 974nm. At equivalent absorbed pump powers between co-doped and single doped materials the relative gain was 1.25dB/cm (Iinc~4kW/cm2) and 0.9dB/cm (Iinc~8kW/cm2) respectively, demonstrating efficient energy transfer from the ytterbium to erbium ions. Excited state absorption at longer wavelengths was observed and characterised and its implication on realising sufficient gain in the wavelength band of interest is discussed

Investigation of Erbium-doped tellurite glasses for a planar waveguide power amplifier at 1.57 microns

Comparing gain in Er-doped tellurite glasses for CO2 absorption measurements, a maximum gain of 2.2dB/cm with 8 ms fluorescence lifetime has been obtained at 1572 nm using a 974 nm pump with intensity of 8kW/cm2

Er-doped tellurite waveguides for power amplifier applications

Tellurite waveguides are promising candidates for high gain with broad-bandwidth, especially with Er-doping, which covers the telecommunications band and important spectral absorption features of atmospheric CO2. This study aimed at developing new Er,Yb-doped tellurite waveguide power amplifier modules suited to LIDAR measurements from space that will enable improved mapping of the concentration and distribution of CO2 in our atmosphere. A comparison of the optical properties of bulk and waveguide samples has been made, with double-clad waveguide devices, suited for high power diode pumping, currently under test

Er-doped planar waveguides for power amplifier applications

New devices are required to provide effective tools for DIAL or LIDAR measurements from space, which will enable improved mapping of the concentration and distribution of CO2 in our atmosphere. Here we present characteristics of Er-doped thin film waveguides, with an extended gain bandwidth, which are applicable to planar waveguide power amplifiers for wavelengths around the 1572 nm CO2 absorption peaks. Planar waveguide films have been fabricated by sputtering of fluorophosphate and tellurite based glasses onto oxidised silicon wafers, and their properties characterized. The deposition parameters for undoped and Er,Yb-doped films have been assessed and studied, achieving losses of <1.5 dB/cm at 633 nm for the as deposited waveguides. A comparison between the two host materials is made and the potential performance discussed

Caloric intake from fast food among children and adolescents in the United States, 2011-2012

Key findingsData from the National Health and Nutrition Examination Survey\ue2\u20ac\ua2 In 2011\ue2\u20ac\u201c2012, just over one-third of children and adolescents consumed fast food on a given day.\ue2\u20ac\ua2 In 2011\ue2\u20ac\u201c2012, children and adolescents consumed on average 12.4% of their daily calories from fast food restaurants.\ue2\u20ac\ua2 Caloric intake from fast foods was higher in adolescents aged 12\ue2\u20ac\u201c19 years than in children aged 2\ue2\u20ac\u201c11 years.\ue2\u20ac\ua2 Non-Hispanic Asian children had significantly lower caloric intake from fast food compared with non-Hispanic white, non-Hispanic black, and Hispanic children.\ue2\u20ac\ua2 No significant differences in caloric intake from fast food were noted by sex, poverty status, or weight status.Consumption of fast food has been linked to weight gain in adults (1). Fast food has also been associated with higher caloric intake and poorer diet quality in children and adolescents (2). From 1994 through 2006, caloric intake from fast food increased from 10% to 13% among children aged 2-18 years (3). This report presents the most recent data on the percentage of calories consumed from fast food among U.S. children by sex, age group, race and Hispanic origin, poverty status, and weight status.Suggested citation: Vikraman S, Fryar CD, Ogden CL. Caloric intake from fast food among children and adolescents in the United States, 2011\ue2\u20ac\u201c2012. NCHS data brief, no 213. Hyattsville, MD: National Center for Health Statistics. 2015CS25871

Leadership in the Service of Hospitality

The definition of leadership has changed considerably in the past one hundred years, beginning with the “great man” concept and, more recently, focusing on “transformational leadership.” The next step in leadership evolution is servant leadership, in which the leader seeks to support and empower followers. The implications are considerable for the hospitality industry, since it is based on the concept of leadership through service. Hospitality educators could take steps to instill servant leadership principles in students to equip them for this increasingly relevant leadership style