Analyzing Partially Correlated Longitudinal Data in Community Survey Research     

Hua Qin  Elizabeth Prentice  Kathlee Freeman 《社会与自然资源》2018,31(1):142-149

Community surveys have been widely used to investigate local residents’ perceptions and behaviors related to natural resource issues. However, most existing community survey research relies on cross-sectional data and is thus unable to capture the temporal dynamics of community processes. Longitudinal analysis has received increasing interest in recent natural resource social science literature. Trend and panel studies are two typical approaches in longitudinal community survey research. Due to limited sampling frames, research design, and respondent attrition, longitudinal community surveys often involve both paired and independent observations across different survey waves. Using previous survey data on community responses to forest insect disturbance in Alaska as an example, this research note shows that the corrected z-test is a more appropriate approach to analyze partially correlated longitudinal data than conventional statistical techniques such as the paired and independent t-tests.  相似文献   

NGC 1705: The missing link between blue compact dwarf and dwarf elliptical galaxies?     

Gerhardt R. Meurer  K. C. Freeman  Michael A. Dopita 《Astrophysics and Space Science》1989,156(1-2):141-151

We report results of a detailed study of the nearby blue compact dwarf galaxy NGC 1705. There are two stellar populations in NGC 1705: an underlying population around a Gyr old or older, and a young population of fairly continuous star formation for the last 250 Myr. An off-centre nucleus, which is probably a young (10 Myr old), massive (10⁶ M ) globular cluster, is part of this young population. The H morphology and emission line kinematics are consistent with an expulsive flow triggered by the formation of the nucleus. We show that NGC 1705 is losing ionized material in this galactic wind with neutral material probably entrained in the flow. This flow may lead to total removal of the ISM. The evolutionary fate of NGC 1705 is uncertain but the most likely outcome is rapid evolution into a nucleated dwarf elliptical galaxy.  相似文献   

Reply to Comment on: Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos,Western Australia     

Anja M. Scheffers  Sander R. Scheffers  Dieter H. Kelletat  Peter Squire  Lindsay Collins  Yuexing Feng  Jian‐Xin Zhao  Renaud Joannes‐Boyau  Simon Matthias May  Gerhard Schellmann  Heather Freeman 《第四纪科学杂志》2013,28(2):213-215

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Steering sustainability in an urbanizing world – Edited by Anitra Nelson     

Claire Freeman 《New Zealand geographer》2010,66(3):232-233

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Probing the high latitude ionosphere from ground-based observations: The state of current knowledge and capabilities during IPY (2007–2009)     

Lucilla Alfonsi  Andrew J. Kavanagh  Ermanno Amata  Pierre Cilliers  Emilia Correia  Mervyn Freeman  Kirsti Kauristie  Ruiyuan Liu  Juha-Pekka Luntama  Cathryn N. Mitchell  G.A. Zherebtsov 《Journal of Atmospheric and Solar》2008,70(18):2293-2308

During the International Polar Year (IPY), one area of great interest is co-coordinated, multi-instrument probing of the ionosphere at high latitudes. This region is important not only for the applications that rely upon our understanding of it, but also because it contains the footprints of processes that have their origin in the interplanetary space. Many different techniques are now available for probing the ionosphere, from radar measurements to the analysis of very low frequency (VLF) wave paths. Combining these methods provides the ability to study the ionosphere from high in the F-region to the bottom of the D-layer. Thus, coupling processes from the magnetosphere and to the neutral atmosphere can be considered. An additional dimension is through comparisons of the response of the two polar ionospheres to similar (or the same) geomagnetic activity. With more instruments available at the South Pole inter-hemispheric, studies have become easier to accomplish such that a fuller picture of the global response to Sun–Earth coupling can be painted.This paper presents a review of the current state of knowledge in ionospheric probing. It cannot provide a comprehensive guide of the work to date due to the scale of the topic. Rather it is intended to give an overview of the techniques and recent results from some of the instruments and facilities that are a part of the IPY cluster 63—Heliosphere Impact on Geospace. In this way it is hoped that the reader will gain a flavor of the recent research performed in this area and the potential for continuing collaboration and capabilities during the IPY (2007–2009).  相似文献   

Structure and kinematics of edge-on galaxy discs – I. Observations of the stellar kinematics     

M. Kregel  P. C. van der Kruit  K. C. Freeman 《Monthly notices of the Royal Astronomical Society》2004,351(4):1247-1265

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Thermal convection with a water ice I rheology: Implications for icy satellite evolution     

J. Freeman  L. Moresi 《Icarus》2006,180(1):251-264

We model stagnant-lid convection for water ice I using a multicomponent rheology, combining grain boundary sliding, dislocation and diffusion creep mechanisms. For the superplastic flow-dislocation creep rheology, dislocation creep (n=4) dominates the deformation within the actively convecting sublayer whilst superplastic flow (n=1.8) is the dominant process within the stagnant-lid whilst for the superplastic flow-diffusion creep rheology, superplastic flow is the dominant deformation mechanism within the convecting sublayer while diffusion creep (n=1) is the dominant deformation process in the stagnant-lid. These results suggest deformation in the actively convecting sublayer is likely to be dominated by the mechanism with the largest stress exponent. We also provide heat flux scaling relationships for the superplastic flow, basal slip, dislocation creep-superplastic flow and superplastic flow-diffusion creep rheologies and provide a simple parameterized convection model of an icy satellite thermal evolution.  相似文献   

A 421-d activity cycle in the BeX recurrent transient A0538–66 from MACHO monitoring     

C. Alcock  R. A. Allsman  D. R. Alves  T. S. Axelrod  A. C. Becker  D. P. Bennett  P. A. Charles  K. H. Cook  A. J. Drake  K. C. Freeman  M. Geha  K. Griest  M. J. Lehner  S. L. Marshall  K. E. McGowan  †  D. Minniti  C. A. Nelson  B. A. Peterson  P. Popowski  M. R. Pratt  P. J. Quinn  C. W. Stubbs  W. Sutherland  A.B. Tomaney  T. Vandehei  D. L. Welch 《Monthly notices of the Royal Astronomical Society》2001,321(4):678-684

We present a ∼5-yr optical light curve of the recurrent Be/X-ray transient A0538–66 obtained as a by-product of the MACHO Project. These data reveal both a long-term modulation at P =420.8±0.8 d and a short-term modulation at 16.6510±0.0022 d which, within errors, confirms the previously found orbital period. Furthermore, the orbital activity is only seen at certain phases of the 421-d cycle, suggesting that the long-term modulation is related to variations in the Be star envelope.  相似文献   

The cosmological significance of low surface brightness galaxies found in a deep blind neutral hydrogen survey     

R. F. Minchin  M. J. Disney  Q. A. Parker  P. J. Boyce  W. J. G. de Blok  G. D. Banks †  R. D. Ekers  K. C. Freeman  D. A. Garcia  B. K. Gibson  M. Grossi  R. F. Haynes  P. M. Knezek  R. H. Lang  D. F. Malin  R. M. Price  M. Putman  I. M. Stewart  A. E. Wright 《Monthly notices of the Royal Astronomical Society》2004,355(4):1303-1314

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Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos,Western Australia     

Anja M. Scheffers  Sander R. Scheffers  Dieter H. Kelletat  Peter Squire  Lindsay Collins  Yuexing Feng  Jian‐Xin Zhao  Renaud Joannes‐Boyau  Simon Matthias May  Gerhard Schellmann  Heather Freeman 《第四纪科学杂志》2012,27(7):713-724

Prehistoric storm records are relatively scarce in most parts of the world. This article presents storm records derived from coral rubble‐based geological archives of the Houtman Abrolhos Archipelago located off the west coast of Australia, where the southernmost coral reefs of the Indian Ocean are found. Winter storm swell from the circum‐Antarctic ‘Brave Westerlies’, as well as tropical cyclone waves, have left numerous ridge systems on dozens of islands of the archipelago, all composed of coral rubble from adjacent reefs. At three islands, seven ridge systems were dated by three different methods: U‐series (68 dates), radiocarbon (64 dates), electron spin resonance (7 dates); 139 radiometric dates span the last 5500 years of the Holocene. In contrast to the geomorphological interpretation, the age sequences show ‘inversions’, hiatuses and different ages for the same ridge, all pointing to complicated ridge formation processes. Time gaps, some exceeding 1000 years, are interpreted as phases of erosion and not as phases without storm activity. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献