Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

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Climate Change 2007: Impacts, Adaptation and Vulnerability.

MUCKE aims to mine a large volume of images, to structure them conceptually and to use this conceptual structuring in order to improve large-scale image retrieval. The last decade witnessed important progress concerning low-level image representations. However, there are a number problems which need to be solved in order to unleash the full potential of image mining in applications. The central problem with low-level representations is the mismatch between them and the human interpretation of image content. This problem can be instantiated, for instance, by the incapability of existing descriptors to capture spatial relationships between the concepts represented or by their incapability to convey an explanation of why two images are similar in a content-based image retrieval framework. We start by assessing existing local descriptors for image classification and by proposing to use co-occurrence matrices to better capture spatial relationships in images. The main focus in MUCKE is on cleaning large scale Web image corpora and on proposing image representations which are closer to the human interpretation of images. Consequently, we introduce methods which tackle these two problems and compare results to state of the art methods. Note: some aspects of this deliverable are withheld at this time as they are pending review. Please contact the authors for a preview.

http://ieeexplore.ieee.org/iel2/4524/12820/00592460.pdf

Image Processing

「脆弱性(Vulnerability)」とは何か

Governing the Commons

Detection of springtime near-surface soil thaw events in mid-latitude areas is important for understanding the near-surface earth surface system. Radar backscatter time series, such as QuikSCAT Ku-band, are valuable for surface thaw detection in permafrost areas, but their usefulness in mid-latitudes remains unverified. In order to validate the application of radar backscatter time series for surface thaw detection in mid-latitude areas, we propose a new multi-step method based on the significant signature of radar backscatter time series when springtime soil thaw events happen. The method mainly focuses on the estimated geographical boundary of thaw events and the detection of the primary thaw date; the duration of the freeze–thaw transition period is a lesser focus. The method is applied to soil freeze–thaw conditions in a mid-latitude area – northern China and Mongolia – including humid land and dryland, and achieves a reliability of R2 = 0.678 ± 0.021 P < 0.01 by comparison with ground truth measurements. The results indicate that elevation/temperature and soil moisture conditions are the key drivers of the timing of springtime soil thaw events. The success of our study demonstrates the potential for our method to be applied in mid-latitude areas, and widens the application potential of radar backscatter time series beyond high north and permafrost studies.

Radar remote sensing of springtime near-surface soil thaw events at mid-latitudes

Biological soil crusts (BSCs) play an essential role in desert ecosystems. Knowledge of the distribution and disappearance of BSCs is vital for the management of ecosystems and for desertification researches. However, the major remote sensing approaches used to extract BSCs are multispectral indices, which lack accuracy, and hyperspectral indices, which have lower data availability and require a higher computational effort. This study employs random forest (RF) models to optimize the extraction of BSCs using band combinations similar to the two multispectral BSC indices (Crust Index-CI; Biological Soil Crust Index-BSCI), but covering all possible band combinations. Simulated multispectral datasets resampled from in-situ hyperspectral data were used to extract BSC information. Multispectral datasets (Landsat-8 and Sentinel-2 datasets) were then used to detect BSC coverage in Mu Us Sandy Land, located in northern China, where BSCs dominated by moss are widely distributed. The results show that (i) the spectral curves of moss-dominated BSCs are different from those of other typical land surfaces, (ii) the BSC coverage can be predicted using the simulated multispectral data (mean square error (MSE) < 0.01), (iii) Sentinel-2 satellite datasets with CI-based band combinations provided a reliable RF model for detecting moss-dominated BSCs (10-fold validation, R2 = 0.947; ground validation, R2 = 0.906). In conclusion, application of the RF algorithm to the Sentinel-2 dataset can precisely and effectively map BSCs dominated by moss. This new application can be used as a theoretical basis for detecting BSCs in other arid and semi-arid lands within desert ecosystems.

A New Application of Random Forest Algorithm to Estimate Coverage of Moss-Dominated Biological Soil Crusts in Semi-Arid Mu Us Sandy Land, China

Efficacy of polyacrylamide (PAM), a water-soluble soil conditioner, prepared with poor-quality water (low salinity, higher sodicity) commonly available to farm managers, is unknown. We studied the ...

Polyacrylamide dissolved in low-quality water effects on structure stability of soils varying in texture and clay type

The state government of Chiapas in Mexico is promoting the cultivation of jatropha by farmers as a source of biofuel, with the first harvest expected in 2012. However, despite the fact that the planted jatropha has now reached the harvesting stage, no reports exist on the current status of jatropha cultivation in Chiapas or on issues related to cultivation. We accordingly conducted a study aimed at ascertaining the current status of jatropha cultivation and identifying factors impeding its spread. For the study, we conducted a questionnaire survey among 88 farmers of 7 villages located within 3 municipalities, and also interviewed them. Our study pointed to 2 key factors causing the abandonment of jatropha cultivation, namely the failure of farmers to receive ProArbol payments as financial assistance for cultivation, and damage caused to jatropha roots by gophers. Pest/disease outbreaks, lack of technical assistance, lack of trust for extension workers and distrust for the project were also obstacles to the spread of jatropha cultivation.

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Identification of Factors Impeding the Spread of Jatropha Cultivation in the State of Chiapas, Mexico

Part of "Proceedings of International Symposium on City Planning 2000, July 17-18, 2000, International Conference Center Kobe, Japan"

Atsushi Tsunekawa

Papers

Radar remote sensing of springtime near-surface soil thaw events at mid-latitudes

A New Application of Random Forest Algorithm to Estimate Coverage of Moss-Dominated Biological Soil Crusts in Semi-Arid Mu Us Sandy Land, China

Polyacrylamide dissolved in low-quality water effects on structure stability of soils varying in texture and clay type

Identification of Factors Impeding the Spread of Jatropha Cultivation in the State of Chiapas, Mexico

Distribution and structure of urban green spaces in Metro Manila