Seismic vulnerability assessment of New Zealand unreinforced masonry churches

Churches are an important part of the New Zealand historical and architectural heritage, and the extensive damage occurred to stone and clay-brick unreinforced masonry portfolio after the 2010-2011 Canterbury earthquakes emphasises the necessity to better understand this structural type. An effort was undertaken to identify the national stock of unreinforced masonry churches and to interpret the damage observed in the area affected by the earthquakes: of 309 religious buildings recognized and surveyed nationwide, a sample of 80 churches belonging to the Canterbury region is studied and their performance analysed statistically. Structural behaviour is described in terms of mechanisms affecting the so-called macro-elements, and discrete local damage levels are correlated firstly with macroseismic intensity through Damage Probability Matrices, computed for the whole building and for each mechanism. The results show that the severity of shaking alone is not capable to fully explain the damage, strongly influenced by structural details that can worsen the seismic performance or improve it through earthquake-resistant elements. Simple-linear regressions, correlating the mean damage of each mechanism with the macroseismic intensity, but neglecting the difference in the vulnerability of different churches subjected to the same level of shaking, are then improved through use of multiple-linear regressions accounting for vulnerability modifiers. Several statistical procedures are considered in order to select the best regression equation and to assess which parameters have closer relationships with damage. Results show good consistency between observed and expected damage, and the proposed regression models can be used as predictive tools to help determine appropriate seismic retrofit measure to be taken. The conclusions drawn for the Canterbury region are then extended to the whole national stock and a quantitative seismic risk assessment for existing unreinforced masonry churches in New Zealand is presented, using different intensity measures to model the seismic hazard. Seismic risk is first computed mechanism by mechanism, highlighting how some mechanisms are more frequent than others, and that very large damage levels are expected for some New Zealand regions. Whereupon, an alternative synthetic damage index purely based on observed data is proposed to summarise damage related to several mechanisms and it is used to validate the choice of the best index for describing the global damage of a church when dealing with a territorial assessment. Territorial scale assessment of the seismic vulnerability of churches can assist emergency management efforts and facilitate the identification of priorities for more in-depth analysis of individual buildings. Finally, a preliminary attempt for dynamically characterize the response of unreinforced masonry church is conducted

Information structure and the referential status of linguistic expression : workshop as part of the 23th annual meetings of the Deutsche Gesellschaft für Sprachwissenschaft in Leipzig, Leipzig, February 28 - March 2, 2001

This volume comprises papers that were given at the workshop Information Structure and the Referential Status of Linguistic Expressions, which we organized during the Deutsche Gesellschaft für Sprachwissenschaft (DGfS) Conference in Leipzig in February 2001. At this workshop we discussed the connection between information structure and the referential interpretation of linguistic expressions, a topic mostly neglected in current linguistics research. One common aim of the papers is to find out to what extent the focus-background as well as the topic-comment structuring determine the referential interpretation of simple arguments like definite and indefinite NPs on the one hand and sentences on the other

Improving the twilight model for polar cap absorption nowcasts

During Solar Proton Events (SPE), energetic protons ionize the polar mesosphere causing HF radiowave attenuation, more strongly on the dayside where the effective recombination coefficient, αeff, is low. Polar cap absorption (PCA) models predict the 30 MHz cosmic noise absorption, A, measured by riometers, based on real-time measurements of the integrated proton flux-energy spectrum, J. However, empirical models in common use cannot account for regional and day-to-day variations in the day- and nighttime profiles of αeff(z) or the related sensitivity parameter, m=A/√J. Large prediction errors occur during twilight when m changes rapidly, and due to errors locating the rigidity cutoff latitude. Modeling the twilight change in m as a linear or Gauss error-function transition over a range of solar-zenith angles (χl < χ < χu) provides a better fit to measurements than selecting day or night αeff profiles based on the Earth-shadow height. Optimal model parameters were determined for several polar cap riometers for large SPEs in 1998-2005. The optimal χl parameter was found to be most variable, with smaller values (as low as 60°) post-sunrise compared with pre-sunset, and with positive correlation between riometers over a wide area. Day and night values of m exhibited higher correlation for closely spaced riometers. A nowcast simulation is presented in which rigidity boundary latitude and twilight model parameters are optimized by assimilating age-weighted measurements from 25 riometers. The technique reduces model bias, and root-mean-squared errors are reduced by up to 30% compared with a model employing no riometer data assimilation

A measurement of the neutron electric form factor at very large momentum transfer using polarized electrons scattering from a polarized helium-3 target

Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q2 and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized 3He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. GEn was measured to be 0.0242 +/- 0.0020(stat) +/- 0.0061(sys) and 0.0247 +/- 0.0029(stat) +/- 0.0031(sys) at Q2 = 1.7 and 2.5 GeV2, respectively