Urban surface temperature time series estimation at the local scale by spatial-spectral unmixing of satellite observations

The study of urban climate requires frequent and accurate monitoring of land surface temperature (LST), at the local scale. Since currently, no space-borne sensor provides frequent thermal infrared imagery at high spatial resolution, the scientific community has focused on synergistic methods for retrieving LST that can be suitable for urban studies. Synergistic methods that combine the spatial structure of visible and near-infrared observations with the more frequent, but low-resolution surface temperature patterns derived by thermal infrared imagery provide excellent means for obtaining frequent LST estimates at the local scale in cities. In this study, a new approach based on spatial-spectral unmixing techniques was developed for improving the spatial resolution of thermal infrared observations and the subsequent LST estimation. The method was applied to an urban area in Crete, Greece, for the time period of one year. The results were evaluated against independent high-resolution LST datasets and found to be very promising, with RMSE less than 2 K in all cases. The developed approach has therefore a high potential to be operationally used in the near future, exploiting the Copernicus Sentinel (2 and 3) observations, to provide high spatio-temporal resolution LST estimates in cities

Earth observation for sustainable urban planning in developing countries: needs, trends, and future directions

Abstract: Cities are constantly changing and authorities face immense challenges in obtaining accurate and timely data to effectively manage urban areas. This is particularly problematic in the developing world where municipal records are often unavailable or not updated. Spaceborne earth observation (EO) has great potential for providing up-to-date spatial information about urban areas. This article reviews the application of EO for supporting urban planning. In particular, the article overviews case studies where EO was used to derive products and indicators required by urban planners. The review concludes that EO has sufficiently matured in recent years but that a shift from the current focus on purely science-driven EO applications to the provision of useful information for day-to-day decision-making and urban sustainability monitoring is clearly needed

Synopsis and meta-analysis of genetic association studies in osteoporosis for the focal adhesion family genes: the CUMAGAS-OSTEOporosis information system

<p>Abstract</p> <p>Background</p> <p>Focal adhesion (FA) family genes have been studied as candidate genes for osteoporosis, but the results of genetic association studies (GASs) are controversial. To clarify these data, a systematic assessment of GASs for FA genes in osteoporosis was conducted.</p> <p>Methods</p> <p>We developed Cumulative Meta-Analysis of GAS-OSTEOporosis (CUMAGAS-OSTEOporosis), a web-based information system that allows the retrieval, analysis and meta-analysis (for allele contrast, recessive, dominant, additive and codominant models) of data from GASs on osteoporosis with the capability of update. GASs were identified by searching the PubMed and HuGE PubLit databases.</p> <p>Results</p> <p>Data from 72 studies involving 13 variants of 6 genes were analyzed and catalogued in CUMAGAS-OSTEOporosis. Twenty-two studies produced significant associations with osteoporosis risk under any genetic model. All studies were underpowered (<50%). In four studies, the controls deviated from the Hardy-Weinberg equilibrium. Eight variants were chosen for meta-analysis, and significance was shown for the variants collagen, type I, α₁(<it>COL1A1</it>) G2046T (all genetic models), <it>COL1A1 </it>G-1997T (allele contrast and dominant model) and integrin β-chain β₃(<it>ITGB3</it>) T176C (recessive and additive models). In <it>COL1A1 </it>G2046T, subgroup analysis has shown significant associations for Caucasians, adults, females, males and postmenopausal women. A differential magnitude of effect in large versus small studies (that is, indication of publication bias) was detected for the variant <it>COL1A1 </it>G2046T.</p> <p>Conclusion</p> <p>There is evidence of an implication of FA family genes in osteoporosis. CUMAGAS-OSTEOporosis could be a useful tool for current genomic epidemiology research in the field of osteoporosis.</p

Uncertainty Estimation of Local-Scale Land Surface Temperature Products over Urban Areas Using Monte Carlo Simulations

Detailed, frequent, and accurate land surface temperature (LST) estimates from satellites may support various applications related to the urban climate. When satellite-retrieved LST is used in modeling, the level of uncertainty is important to account for. In this letter, an uncertainty estimation scheme based on Monte Carlo simulations is proposed for local-scale LST products derived from image fusion. The downscaling algorithm combines frequent low-resolution thermal measurements with surface cover information from high spatial resolution imagery. The uncertainty is estimated for all the intermediate products, allowing the analysis of individual uncertainties and their contribution to the final LST product. Uncertainties of less than 2 K was found for most part of the test area. The uncertainty estimation method, although demanding in terms of computations, can be useful for the uncertainty analysis of other satellite products

SHALLOW-WATER BATHYMETRY OVER VARIABLE BOTTOM TYPES USING MULTISPECTRAL WORLDVIEW-2 IMAGE

Image processing techniques that involve multispectral remotely sensed data are considered attractive for bathymetry applications as they provide a time- and cost-effective solution to water depths estimation. In this paper the potential of 8-bands image acquired by Worldview-2 satellite in providing precise depth measurements was investigated. Multispectral image information was integrated with available echo sounding and GPS data for the determination of the depth in the area of interest. In particular the main objective of this research was to evaluate the effectiveness of high spatial and spectral resolution of the new imagery data on water depth measurements using the Lyzenga linear bathymetry model. The existence of sea grass in a part of the study area influenced the linear relationship between water reflectance and depth. Therefore the bathymetric model was applied in three image parts: an area with sea grass, a mixed area and a sea grass-free area. In the last two areas the model worked successfully supported by the multiplicity of the imagery bands

Tree number estimation with the use of VHR natural colour orthophotos over a heterogeneous landscape in northern Greece

Spatial explicit knowledge regarding the quantity and the spatial distribution of forest parameters is crucial for sustainable forest management, as well as in fulfilling national reporting needs in the framework of international treaties (i.e. Kyoto Protocol, FAO, EFFIS etc). Especially, tree number which can be used for assessing forest tree density (tree number/ha), is among the most important and laboursome parameters to be measured in the field. The aim of this study is to estimate tree number based on the use of nationwide, freely available, very high spatial resolution orthophotos acquired from Greek National Cadastre and Mapping Agency during the 2007-2009 period. The study area is the University Forest of Taxiarchis, which is located in central Halkidiki, Northern Greece. The dominant species of the forest includes both broadleaves (oak, beech) and coniferous species (Black pine, Calabrian pine), which are found in both pure and mixed stands. Tree crown detection was tested on natural color orthophoto bands in several plots. The principal components and intensity-hue-saturation transformations were also applied in order to enhance tree detection accuracy. Local maxima technique was utilized for tree crown detection. Accuracy results were evaluated based on field plot data available from the official forest management plan of the area completed in 2011. Overall, the detection accuracy exceeded 50% which is deemed satisfactory considering also the heterogeneity of the Mediterranean landscape and the limited spectral resolution of the remote sensing data available

Network Analysis of Randomized Controlled Trials in Multiple Sclerosis

Background: The optimal treatment of multiple sclerosis (MS) is not yet well-defined. Objective: To estimate the relative effectiveness of treatments in MS, we performed a network of multiple-treatments meta-analysis of randomized controlled trials (RCTs) for relapsing MS using three main efficacy outcomes: relapse-free patients, patients without disease progression, and patients without magnetic resonance imaging progression. Methods: We systematically searched PubMed and the Cochrane Central Register of Controlled Trials to identify English-language articles with RCTs that compared pharmaceutical treatments using the terms multiple sclerosis and randomized controlled trial. All RCTs that involved patients with definite relapsing MS and provided data for calculating the odds ratios for the main outcomes were considered. First, comparative effectiveness relative to placebo was assessed using direct analysis. Then, each therapy was compared with interferon beta-1b (250 mu g)(star) in direct and indirect analyses. Effect sizes were estimated by applying a random-effects model. Results: We identified 4165 titles; after screening, 109 articles were eligible for inclusion. In total, 26,828 patients were included. The network consisted of 145 treatments involving 59 direct comparisons with placebo and 3 direct comparisons with interferon beta-1b (250 mu g). Two treatments showed better response compared with placebo (direct analysis) for all three efficacy outcomes: natalizumab (300 mg)(dagger) and fingolimod (0.5 mg). In comparing treatments with interferon beta-1b (250 mu g), the network analysis revealed that no therapy shows better response for all 3 efficacy outcomes and alemtuzumab, 12 and 24 mg, have better response for 2 of the outcomes (relapse-free patients and patients without disease progression). Conclusions: Although some treatments seem to have better efficacy, the results should be interpreted with caution because the network was dominated by indirect comparisons. Data from the selected studies included in the network cannot be extrapolated beyond them. Large RCTs that make head-to-head comparisons between treatments are needed to draw safe conclusions for the optimal treatment of MS. (Clin Ther. 2012;34:857-869) (C) 2012 Elsevier HS Journals, Inc. All rights reserved