Incompatibility of trends in multi-year estimates from the American Community Survey

The American Community Survey (ACS) provides one-year (1y), three-year (3y) and five-year (5y) multi-year estimates (MYEs) of various demographic and economic variables for each "community", although the 1y and 3y may not be available for communities with a small population. These survey estimates are not truly measuring the same quantities, since they each cover different time spans. Using some simplistic models, we demonstrate that comparing different period-length MYEs results in spurious conclusions about trend movements. A simple method utilizing weighted averages is presented that reduces the bias inherent in comparing trends of different MYEs. These weighted averages are nonparametric, require only a short span of data, and are designed to preserve polynomial characteristics of the time series that are relevant for trends. The basic method, which only requires polynomial algebra, is outlined and applied to ACS data. In some cases there is an improvement to comparability, although a final verdict must await additional ACS data. We draw the conclusion that MYE data is not comparable across different periods.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS259 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Simulation, no problem, of course we offer this service! (observations on firms who have worked to make this true)

The paper focuses on the practical experiences of a number of professional firms striving to use simulation to deliver information of value to their clients. It exposes issues such as limitations in existing working practices and the mismatch between language routinely used by facilitators and trainees as well as their different expectations. The paper also discusses the differences observed between incremental implementation of simulation within practices and firms who wished to "jump in at the deep end". Lastly, it addresses the dilemma of how to move simulation tools into the already busy schedules and overloaded programmes of design practices successfully

Dispersant Efficacy and Effectiveness

Dispersants have been researched extensively and used for oil spill mitigation for more than 40 years, yet there are opportunities to enhance our understanding, including with respect to their long term fate and effects and how to optimize dispersant use. For example, the 2005 National Academy of Sciences report, Understanding Oil Spill Dispersants: Efficacy and Effects, suggested a number of areas where increased understanding would help support the use of dispersants. Throughout the summer of 2010 dispersants were used in unprecedented quantities and, in the case of sub-sea application, with novel application methods following the Deepwater Horizon incident. The focus of this paper is to provide a brief overview of spilled oil behavior, chemical dispersants efficacy and effectiveness, and a discussion of the state of knowledge pre-, during, and post- Deepwater Horizon

SPE water electrolyzers in support of the lunar outpost

During the 1970s, the SPE water electrolyzer, which uses ion exchange membranes as its sole electrolyte, was developed for nuclear submarine metabolic oxygen production. These developments included SPE water electrolyzer operation at up to 3,000 psia and at current densities in excess of 1,000 amps per square foot. The SPE water electrolyzer system is now fully qualified for both the U.S. and U.K. Navies with tens of thousands of system hours accumulated at sea. During the 1980s, the basic SPE water electrolyzer cell structure developed for the Navies was incorporated into several demonstrations for NASA's Space Station Program. Among these were: the SPE regenerative fuel cell for electrical energy storage; the SPE water electrolyzer for metabolic oxygen production; and the high pressure SPE water electrolyzer for reboost propulsion reactant production. In the 1990s, one emphasis will be the development of SPE water electrolyzers for the Lunar Outposts Currently defined potential Lunar Outpost applications for the SPE water electrolyzer include: SPE water electrolyzers for metabolic oxygen and potable water production from reclaimed water; and SPE water electrolyzers operating at high pressure as part of stationary and mobile surface energy storage systems

The Effect of Attendance on Grade for First Year Economics Students in University College Cork

This paper examines the relationship between attendance and grade, controlling for other factors, in first year economics courses in University College Cork. Determinants of both class attendance and grade are specified and estimated. We find that attendance is low, at least by comparison with US evidence. Hours worked and travel time are among the factors affecting class attendance. Class attendance, and especially tutorial attendance has a positive and diminishing marginal effect on grade, while hours worked in a part-time job have a significant negative effect on grade.

Party Groups and Policy Positions in the European Parliament

As the legislative body of the European Union, the European Parliament groups 732 elected representatives from over 170 national political parties from 25 member states. At the EP level, these members are affiliated with seven major party groups representing distinct policy positions. In this paper we provide precise estimates of these policy positions based on expert surveys in addition to characterizing the dimensionality of policy competition in the EP. Our results suggest not only that party groups have identifiable and differentiated positions on multiple issues of policy, but also that these positions group broadly into two orthogonal dimensions: one consisting of classic left-right social and economic issues, and the other related to the powers and scope of EU institutions.Party Competition, Policy Positions, European Parliament, Expert Surveys.

Thermal mass, insulation and ventilation in sustainable housing - An investigation across climate and occupancy

Sustainable housing standards are reviewed including the UK 2005 building regulations, the UK Advanced Standard and EU Passive-house Standard. Conflicts between the standards are highlighted. The significance of insulation, orientation, ventilation, thermal mass, occupancy, gains, shading and climate on predicted energy performance is illustrated. An ESP-r model is then used to investigate these factors across a range of climates and occupancy / gains scenarios. The investigation covers both heating and cooling energy requirements. The relative importance of key factors is quantified and a matrix of results presented with conclusions. The role of simulation in informing design decisions is demonstrated as well as the importance of considering climate and occupancy/ gains patterns

Global Change: A Biogeochemical Perspective

A research program that is designed to enhance our understanding of the Earth as the support system for life is described. The program change, both natural and anthropogenic, that might affect the habitability of the planet on a time scale roughly equal to that of a human life is studied. On this time scale the atmosphere, biosphere, and upper ocean are treated as a single coupled system. The need for understanding the processes affecting the distribution of essential nutrients--carbon, nitrogen, phosphorous, sulfur, and water--within this coupled system is examined. The importance of subtle interactions among chemical, biological, and physical effects is emphasized. The specific objectives are to define the present state of the planetary life-support system; to ellucidate the underlying physical, chemical, and biological controls; and to provide the body of knowledge required to assess changes that might impact the future habitability of the Earth

Documentation for the spatial analysis system (SPAN) for resource use by animals

Nearest-neighbor analyses have been used with mapped data f or tests of spatial dispersion and association i n plant and animal ecology. This paper full describes a computer software package developed to use Monte Carlo trials instead of chi-squared distributions for assigning probabilities to observed values of nearest neighbor statistics. The program can factor-out the unique geometry of resources in a sample plot,which can affect locations of animals, thus testing for direct patterns among the animals independent of their resource patterns. The Kappa statistic for association is a1 o calculated a1though its application has met with limited success. A users manual and the Fortran program language is included. (80pp.

Continuum Contributions to the SDO/AIA Passbands During Solar Flares

Data from the Multiple EUV Grating Spectrograph (MEGS-A) component of the Extreme Ultraviolet Experiment (EVE) onboard the Solar Dynamics Observatory (SDO) were used to quantify the contribution of continuum emission to each of the EUV channels of the Atmospheric Imaging Assembly (AIA), also on SDO, during an X-class solar flare that occurred on 2011 February 15. Both the pre-flare subtracted EVE spectra and fits to the associated free-free continuum were convolved with the AIA response functions of the seven EUV passbands at 10 s cadence throughout the course of the flare. It was found that 10-25% of the total emission in the 94A, 131A, 193A, and 335A passbands throughout the main phase of the flare was due to free-free emission. Reliable measurements could not be made for the 171A channel, while the continuum contribution to the 304A channel was negligible due to the presence of the strong He II emission line. Up to 50% of the emission in the 211A channel was found to be due to free-free emission around the peak of the flare, while an additional 20% was due to the recombination continuum of He II. The analysis was extended to a number of M- and X-class flares and it was found that the level of free-free emission contributing to the 171A and 211A passbands increased with increasing GOES class. These results suggest that the amount of continuum emission that contributes to AIA observations during flares is more significant than that stated in previous studies which used synthetic, rather than observed, spectra. These findings highlight the importance of spectroscopic observations carried out in conjunction with those from imaging instruments so that the data are interpreted correctly.Comment: 9 pages, 6 figures, 1 tabl