51 research outputs found
Discriminating small wooded elements in rural landscape from aerial photography: a hybrid pixel/object-based analysis approach
While small, fragmented wooded elements do not represent a large surface area in
agricultural landscape, their role in the sustainability of ecological processes is
recognized widely. Unfortunately, landscape ecology studies suffer from the lack
of methods for automatic detection of these elements. We propose a hybrid
approach using both aerial photographs and ancillary data of coarser resolution
to automatically discriminate small wooded elements. First, a spectral and textural
analysis is performed to identify all the planted-tree areas in the digital photograph.
Secondly, an object-orientated spatial analysis using the two data sources
and including a multi-resolution segmentation is applied to distinguish between
large and small woods, copses, hedgerows and scattered trees. The results show the
usefulness of the hybrid approach and the prospects for future ecological
applications
BiodiversitĂ© et services rendus Ă lâagriculture. Principaux enseignements de diffĂ©rents dispositifs de recherche rĂ©cents et actuels en Midi-PyrĂ©nĂ©es
Dans le canton dâAurignac, des chercheurs de lâInstitut national de la recherche agronomique et de lâInstitut national polytechnique de Toulouse travaillent depuis une trentaine dâannĂ©es sur lâagriculture, les paysages et la biodiversitĂ©. Les paysages agricoles Ă©tudiĂ©s sont caractĂ©risĂ©s par une agriculture de polyculture Ă©levage et la prĂ©sence de petits bois. Ces paysages agri-forestiers constituent un site dâĂ©tude Ă long terme qui est reconnu au niveau national et europĂ©en
Detecting clear-cuts and decreases in forest vitality using MODIS NDVI time series
This paper examines the potential of MODIS-NDVI time series for detecting clear-cuts in a coniferous forest stand in the south of France. The proposed approach forms part of a survey monitoring the status of forest health and evaluating the forest decline phenomena observed over the last few decades. One of the prerequisites for this survey was that a rapid and easily reproducible method had to be developed that differentiates between forest clear-cuts and changes in forest health induced by environmental factors such as summer droughts. The proposed approach is based on analysis of the breakpoints detected within NDVI time series, using the "Break for Additive Seasonal and Trend" (BFAST) algorithm. To overcome difficulties detecting small areas on the study site, we chose a probabilistic approach based on the use of a conditional inference tree. For model calibration, clear-cut reference data were produced at MODIS resolution (250 m). According to the magnitude of the detected breakpoints, probability classes for the presence of clear-cuts were defined, from greater than 90% to less than 3% probability of a clear-cut. One of the advantages of the probabilistic model is that it allows end users to choose an acceptable level of uncertainty depending on the application. In addition, the use of BFAST allows events to be dated, thus making it possible to perform a retrospective analysis of decreases in forest vitality in the study area
Non-renormalization for planar Wess-Zumino model
Using a non-perturbative functional method, where the quantum fluctuations
are gradually set up,it is shown that the interaction of a N=1 Wess-Zumino
model in 2+1 dimensions does not get renormalized. This result is valid in the
framework of the gradient expansion and aims at compensating the lack of
non-renormalization theorems
Cost Burden of Illness for Hepatitis C Patients with Employer-Sponsored Health Insurance
The disease burden of hepatitis C virus (HCV) is expected to more than double in the next two decades. Currently, there is very little information about the costs of HCV treatment for employers who pay for treatment and health plans that cover HCV patients. This study reports the medical costs of HCV for workers with health insurance. A retrospective claims data design was used for this study. A sample of HCV patients with health insurance was drawn from the inpatient, outpatient, and enrollment files of the MEDSTAT Group's MarketScan family of databases for 1993-1998. Patients were grouped into cohorts and studied for up to 2 years before and after HCV diagnosis. Sample size varies according to length of follow-up, peaking at 3,077 patients enrolled for at least 6 months. In the first year following HCV diagnosis, average payments for HCV patients (1,186). Doctors are encouraged to test high-risk patients to find HCV patients earlier in the course of their disease and to better manage their care in order to avoid unnecessary illness and expenses for this disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63140/1/109350702320229195.pd
Comprendre la dynamique régionale des exploitations de polyculture élevage pour accompagner le développement rural dans les Coteaux de Gascogne
Les Coteaux de Gascogne constituent un des terrains de recherche sur lâavenir des paysages ruraux et la durabilitĂ© de la gestion des ressources naturelles. Cette petite rĂ©gion du Sud-Ouest de la France est historiquement fondĂ©e sur un systĂšme social dit « Ă maison » caractĂ©risĂ© par une permanence des patrimoines fonciers et des exploitations agricoles. Le systĂšme agraire qui lui est liĂ© gĂ©nĂšre une mosaĂŻque de paysages composĂ©e de grandes cultures, de prairies liĂ©es Ă lâĂ©levage bovin et de bois. Lâagriculture locale a connu, depuis les annĂ©es 1950, de profonds changements liĂ©s Ă la modernisation et Ă lâagrandissement des exploitations. A lâorigine trĂšs diversifiĂ©es et tournĂ©es vers lâautoconsommation, les exploitations sâinscrivent aujourdâhui dans lâĂ©conomie de marchĂ© tout en conservant une orientation de polyculture-Ă©levage. Dans une perspective dâĂ©laboration de scĂ©narios dâĂ©volution relatifs Ă lâĂ©levage, nous avons mis en place un dispositif de recherche en partenariat. Il a Ă©tĂ© convenu, avec les partenaires, que la premiĂšre Ă©tape de nos travaux porte sur lâamĂ©lioration de la connaissance des changements en cours dans les exploitations et la comprĂ©hension des stratĂ©gies des familles agricoles. A partir dâune enquĂȘte exhaustive et spatialisĂ©e des exploitations utilisant le territoire de quatre communes, nous avons, en premier lieu, Ă©laborĂ© une typologie pour disposer dâune reprĂ©sentation de la diversitĂ© de leurs situations. Les modes dâorganisation spatiale et fonctionnelle des territoires dâexploitation montrent des situations contrastĂ©es liĂ©es Ă leur dimension et Ă leur accĂšs aux ressources fonciĂšres. La transmission des exploitations et lâavenir de lâĂ©levage bovin sont des questions pressantes qui constituent des Ă©lĂ©ments Ă intĂ©grer dans les modĂšles et scĂ©narios Ă Ă©laborer
Les territoires d'exploitations agricoles qui pratiquent des systÚmes de production différents présentent-ils une biodiversité différente? L'exemple des oiseaux nicheurs
Agri-environmental policies are most often applied at the individual farm level. An improved effectiveness of these policies could result from an it is then necessary to study the ecological patterns by consi dering the level of agricultural organisation. However, many studies are currently lead at the field scale or the landscape scale without considering the whole farm territory. Our study focus on the relationships between bird diversity in farmland and spatial patterns of farming system types regarded as a level of agricultural organisation.We test 2 hypotheses:
-The farming systems can discriminate bird diversity.
- Landscape areas with extensive farming systems have an higher bird diversity than the ones with intensive farming systems because they include more semi-natural elements
Sylviculture et nutrition des accrus de frĂȘne dans les Hautes-PyrĂ©nĂ©es
Le projet CHAPAY a contribuĂ© Ă produire des connaissances, des mĂ©thodes et des outils pour prendre en compte les relations entre le changement des activitĂ©s agricoles et des paysages dans lâaction publique et la gouvernance des territoires. Le frĂȘne trouve dans de nombreux sites des Hautes-PyrĂ©nĂ©es des conditions favorables Ă son installation, mais sa croissance est trĂšs variable selon les stations. Lâexploitation forestiĂšre de ces accrus nĂ©cessite, au prĂ©alable, une connaissance du potentiel de croissance auquel on peut sâattendre selon la fertilitĂ© de la station concernĂ©e. Nos rĂ©sultats sont fondĂ©s sur une Ă©tude de terrain portant sur des accrus reprĂ©sentatifs des Hautes-PyrĂ©nĂ©es. Nous les avons classĂ©s en niveaux de potentiel de croissance actuels et futurs et nous avons interprĂ©tĂ© ces niveaux par rapport aux donnĂ©es de fertilitĂ© chimique des stations. Cette mĂ©thodologie peut ĂȘtre Ă©tendue Ă dâautres rĂ©gions et Ă dâautres types dâaccrus. Elle peut servir de base Ă une catĂ©gorisation des accrus selon leur intĂ©rĂȘt Ă©cologique ou Ă©conomique
An integrative multiâscale approach to regional agriculture to support the assessment and benefit of pestâregulation services delivered by biodiversity
Ecology is first of all a scientific discipline, with its body of theories and methods, and a constant renewal of its main specific fields and principles. In that regard, Ecology is not different from the other scientific disciplines and produces an increasing number of outstanding publications on both fundamental and applied grounds. Ecology can produce highly theoretical works, which is essential, but Ecology can be -and even moremust be an applied science. Currently, practical applications of Ecology for the benefits of our societies have become more numerous and increasingly urgent. âInteractionsâ, sensu lato, are at the very heart of Ecology which makes it by definition THE science of Biodiversity. Beyond the knowledge of how Life has appeared and developed, Ecology can provide the basis for the preservation of Biodiversity and ensure its management is relevant and efficient into the future. By being more integrative and global, Ecology could establish itself as the cornerstone of sustainable development. In this beginning of the 21st century, the influence of Ecology will inevitably grow and play a key role for Planet Earth and human well-being. SfĂ©cologie2016, an International Conference on ecological sciences would not have taken place without 2 years of hard work from the staff of my Institute (IMBE). That is thus with a real pleasure that we welcome you today in Marseille. (Thierry TATONI IMBE Director
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