Unsupervised classification of changes in multispectral satellite imagery

The statistical techniques of multivariate alteration detection, maximum autocorrelation factor transformation, expectation maximization, fuzzy maximum likelihood estimation and probabilistic label relaxation are combined in a unified scheme to classify changes in multispectral satellite data. An example involving bitemporal LANDSAT TM imagery is given

Visualization of and Software for Omnibus Test Based Change Detected in a Time Series of Polarimetric SAR Data

Based on an omnibus likelihood ratio test statistic for the equality of several variance-covariance matrices following the complex Wishart distribution and a factorization of this test statistic with associated p-values, change analysis in a time series of multilook polarimetric synthetic aperture radar data in the covariance matrix representation is carried out. The omnibus test statistic and its factorization detect if and when change occurs. Using airborne EMISAR and spaceborne RADARSAT-2 data, this article focuses on change detection based on the p-values, on visualization of change at pixel as well as segment level, and on computer software

Automatic Radiometric Normalization of Multitemporal Satellite Imagery

The linear scale invariance of the multivariate alteration detection (MAD) transformation is used to obtain invariant pixels for automatic relative radiometric normalization of time series of multispectral data. Normalization by means of ordinary least squares regression method is compared with normalization using orthogonal regression. The procedure is applied to Landsat TM images over Nevada, Landsat ETM+ images over Morocco, and SPOT HRV images over Kenya. Results from this new automatic, combined MAD/orthogonal regression method, based on statistical analysis of test pixels not used in the actual normalization, compare favorably with results from normalization from manually obtained time-invariant features. (C) 2004 Elsevier Inc. All rights reserved

Post-exercise cold-water immersion modulates skeletal muscle PGC-1α mRNA expression in immersed and non-immersed limbs: evidence of systemic regulation

Mechanisms mediating post-exercise cold-induced increases in PGC-1α gene expression in human skeletal muscle are yet to be fully elucidated, but may involve local cooling effects on AMPK and p38 MAPK related signalling and/or increased systemic β-adrenergic stimulation. We aimed to therefore examine whether post-exercise cold-water immersion enhancement of PGC-1α mRNA is mediated through local or systemic mechanisms. Ten subjects completed acute cycling (8x5 min at ~80% peak power output) followed by seated-rest (CON) or single-leg cold-water immersion (CWI; 10 min, 8°C). Muscle biopsies were obtained pre-, post- and 3 h post-exercise from a single limb in the CON condition but from both limbs in CWI (thereby providing tissue from a CWI and non-immersed limb, NOT). Muscle temperature decreased up to 2 h post-exercise following CWI (-5°C) in the immersed limb, with lesser changes observed in CON and NOT (-3°C; P<0.05). No differences between limbs were observed in p38MAPK phosphorylation at any time point (P<0.05), whilst a significant interaction effect was present for AMPK phosphorylation (P=0.031). Exercise (CON) increased gene expression of PGC-1α 3 h post-exercise (~5-fold; P<0.001). CWI augmented PGC-1α expression above CON in both the immersed (CWI; ~9-fold; P=0.003) and NOT limbs (~12-fold; P=0.001). Plasma Normetanephrine concentration was higher in CWI vs. CON immediately post-immersion (860 vs. 665 pmol/L; P=0.034). We report for the first time that local cooling of the immersed limb evokes transcriptional control of PGC1-α in the non-immersed limb, suggesting increased systemic β-adrenergic activation of AMPK mediates, in part, post-exercise cold-induction of PGC-1α mRNA

Low pre-exercise muscle glycogen availability offsets the effect of post-exercise cold water immersion in augmenting PGC-1α gene expression

We assessed the effects of post-exercise cold-water immersion (CWI) in modulating PGC-1α expression in response to exercise commenced with low muscle glycogen availability. In a randomized repeated-measures design, nine recreationally active males completed an acute two-legged high-intensity cycling protocol (8 x 5 min at 82.5% peak power output) followed by 10 minutes of two-legged post-exercise CWI (8°C) or control conditions (CON). During each trial, one limb commenced exercise with low (LOW: <300 mmol.kg-1 dw) or very low (VLOW: <150 mmol.kg-1 dw) pre-exercise glycogen concentration, achieved via completion of a one-legged glycogen depletion protocol undertaken the evening prior. Exercise increased (P<0.05) PGC-1α mRNA at 3 h post-exercise. Very low muscle glycogen attenuated the increase in PGC-1α mRNA expression compared with the LOW limbs in both the control (CON VLOW ~3.6-fold vs. CON LOW ~5.6-fold: P = 0.023, ES 1.22 Large) and CWI conditions (CWI VLOW ~2.4-fold vs. CWI LOW ~8.0 fold: P = 0.019, ES 1.43 Large). Furthermore, PGC-1α mRNA expression in the CWI-LOW trial was not significantly different to the CON LOW limb (P = 0.281, ES 0.67 Moderate). Data demonstrate that the previously reported effects of post-exercise CWI on PGC-1α expression (as regulated systemically via β-adrenergic mediated cell signalling) are offset in those conditions in which local stressors (i.e. high-intensity exercise and low muscle glycogen availability) have already sufficiently activated the AMPK- PGC-1α signaling axis. Additionally, data suggest that commencing exercise with very low muscle glycogen availability attenuates PGC-1α signaling

In search of the authentic nation: landscape and national identity in Canada and Switzerland

While the study of nationalism and national identity has flourished in the last decade, little attention has been devoted to the conditions under which natural environments acquire significance in definitions of nationhood. This article examines the identity-forming role of landscape depictions in two polyethnic nation-states: Canada and Switzerland. Two types of geographical national identity are identified. The first – what we call the ‘nationalisation of nature’– portrays zarticular landscapes as expressions of national authenticity. The second pattern – what we refer to as the ‘naturalisation of the nation’– rests upon a notion of geographical determinism that depicts specific landscapes as forces capable of determining national identity. The authors offer two reasons why the second pattern came to prevail in the cases under consideration: (1) the affinity between wild landscape and the Romantic ideal of pure, rugged nature, and (2) a divergence between the nationalist ideal of ethnic homogeneity and the polyethnic composition of the two societies under consideration