487 research outputs found
Ten years of ecosystem services matrix: Review of a (r)evolution
With the Ecosystem Service (ES) concept's popularisation, the need for robust and practical methodologies for ES assessments has increased. The ES matrix approach, linking ecosystem types or other geospatial units with ES in easy-to-apply lookup tables, was first developed ten years ago and, since then, has been broadly used. Whereas detailed methodological guidelines can be found in literature, the ES matrix approach seems to be often used in a quick (and maybe even "quick and dirty”) way. Based on a reviewa of scientific publications, in which the ES matrix approach was used, we present the diversity of application contexts, highlight trends of uses and propose future recommendations for improved applications of the ES matrix. A total of 109 studies applying the ES matrix approach and one methodological study without concrete applications were considered for the review. Amongst the main patterns observed, the ES matrix approach allows the assessment of a higher number of ES than other ES assessment methods. ES can be jointly assessed with indicators for ecosystem condition and biodiversity in the ES matrix. Although the ES matrix allows us consider many data sources to achieve the assessment scores for the individual ES, in the reviewed studies, these were mainly used together with expert-based scoring (73%) and/or ES scores that were based on an already-published ES matrix or deduced by information found in related scientific publications (51%). We must acknowledge that 27% of the studies did not clearly explain their methodology. This points out a lack of method elucidation on how the data had been used and where the scores came from. Although some studies addressed the need to consider variabilities and uncertainties in ES assessments, only a minority of studies (15%) did so. Our review shows that, in 29% of the studies, an already-existing matrix was used as an initial matrix for the assessment (mainly the same matrix from one of the Burkhard et al. papers). In 16% of the reviewed studies, no other data were used for the matrix scores or no adaptation of the existing matrix used was made. However, the actual idea of the ES scores, included in the Burkhard et al.'s matrices published 10 years ago, was to provide some examples and give inspiration for one's own studies. Therefore, we recommend to use only scores assessed for a specific study or, if one wishes to use pre-existing scores from another study, to revise them in depth, taking into account the local context of the new assessment. We also recommend to systematically report and consider variabilities and uncertainties in each ES assessment. We emphasise the need for all scientific studies to describe clearly and extensively the whole methodology used to score or evaluate ES in order to be able to rate the quality of the scores obtained. In conclusion, the application of the ES matrix has to become more transparent and integrate more variability analyses. The increasing number of studies that use the ES matrix approach confirms its success, appropriability, flexibility and utility for decision-making, as well as its ability to increase awareness of ES
Anomaly Detection in the Molecular Structure of Gallium Arsenide Using Convolutional Neural Networks
This paper concerns the development of a machine learning tool to detect anomalies in the molecular structure of Gallium Arsenide. We employ a combination of a CNN and a PCA reconstruction to create the model, using real images taken with an electron microscope in training and testing. The methodology developed allows for the creation of a defect detection model, without any labeled images of defects being required for training. The model performed well on all tests under the established assumptions, allowing for reliable anomaly detection. To the best of our knowledge, such methods are not currently available in the open literature; thus, this work fills a gap in current capabilities
Spatio-temporal growth dynamics of a subAlpine <i>Pinus uncinata</i> stand in the French Alps
The Flora in the vineyards of Pays d’Aigues (Provence, France) - from a poorly known area to the biology of its species
Dans ce travail ont été étudiées les influences des pratiques agricoles, du contexte paysager et de la localisation des relevés dans les parcelles sur la composition et la richesse floristique de la végétation du vignoble du Pays d'Aigues. Suivant une stratification des relevés selon ces trois facteurs et pour trois niveaux de perception, 135 relevés ont été effectués. L'analyse de variance réalisée sur le nombre d'espèces par relevé a révélé une influence significative du type d'habitat, des pratiques agricoles et moins fortement du type de paysage. Les types de paysage retenus ont été définis préalablement à partir des données géographiques disponibles (géologie, occupation de sol, relief). A posteriori, une analyse de l'histoire des parcelles a montré l'importance de ce facteur pour la présence d'un groupe écologique – les plantes liées aux céréales encore appelées « messicoles ». Une comparaison de la longévité des graines des espèces messicoles dans les vignes comparées à celles connues seulement dans les champs de céréales suggère qu’elles ne sont pas de simples résurgences en provenance de la banque de graines du sol mais qu’il existe une pérennité du maintien de ces populations depuis que les parcelles étaient cultivées en céréales.In this work the influence of three factors on species composition and richness has been studied. 135 relevés have been made, stratified according to these factors. A factorial analysis of variance (ANOVA) on the species number revealed a significant relation between vineyard habitat type, agricultural practices and -less strong- landscape type. The landscape types used to stratify the relevés have previously been determined on the base of geographic data (geology, landuse, relief). Afterwards an analysis of a single group of species known to be allied to cereal-fields called «segetals » has been done. This group turned out to be better represented in vineyards with former cereal cultivation than with a longer vineyard tradition. An analysis of the longevity of seeds of this species and those segetal species only occurring in cereals showed that the segetal species found in vineyards form not more often a persistant seed bank than those only found in cereal fields, suggesting that there is a continuity of this population in the vineyards since the times of cereal cultivation
Warm Saturns: On the Nature of Rings around Extrasolar Planets that Reside Inside the Ice Line
We discuss the nature of rings that may exist around extrasolar planets.
Taking the general properties of rings around the gas giants in the Solar
System, we infer the likely properties of rings around exoplanets that reside
inside the ice line. Due to their proximity to their host star, rings around
such exoplanets must primarily consist of rocky materials. However, we find
that despite the higher densities of rock compared to ice, most of the observed
extrasolar planets with reliable radii measurements have sufficiently large
Roche radii to support rings. For the currently known transiting extrasolar
planets, Poynting-Robertson drag is not effective in significantly altering the
dynamics of individual ring particles over a time span of years provided
that they exceed about 1 m in size. In addition, we show that significantly
smaller ring particles can exist in optically thick rings, for which we find
typical ring lifetimes ranging from a few times to a few times
years. Most interestingly, we find that many of the rings could have nontrivial
Laplacian planes due to the increased effects of the orbital quadrupole caused
by the exoplanets' proximity to their host star, allowing a constraint on the
of extrasolar planets from ring observations. This is particular
exciting, since a planet's reveals information about its interior
structure. Furthermore, measurements of an exoplanet's oblateness and of its
, from warped rings, would together place limits on its spin period. Based
on the constraints that we have derived for extrasolar rings, we anticipate
that the best candidates for ring detections will come from transit
observations by the Kepler spacecraft of extrasolar planets with semi-major
axes AU and larger.Comment: Accepted for publication in Ap
Impacts of urbanization around Mediterranean cities : changes in ecosystem service supply
Unidad de excelencia María de Maeztu MdM-2015-0552Urbanization is an important driver of changes in land cover in the Mediterranean Basin and it is likely to impact the supply and demand of ecosystem services (ES). The most significant land cover changes occur in the peri-urban zone, but little is known about how these changes affect the ES supply. For eight European and four North African cities, we have quantified changes in peri-urban land cover, for periods of sixteen years (1990-2006) in the Northern African, and twenty-two years (1990-2012) in the European cities, respectively. Using an expert-based method, we derived quantitative estimates of the dynamics in the supply of twenty-seven ES. The nature of land cover changes slightly differed between European and North African Mediterranean cities, but overall it increased in urban areas and decreased in agricultural land. The capacity of the peri-urban areas of Mediterranean cities to supply ES generally reduced over the last 20-30 years. For nine ES the potential supply actually increased for all four North African cities and three out of the eight European cities. Across all cities, the ES timber, wood fuel and religious and spiritual experience increased. Given the expected increase of urban population in the Mediterranean Basin and the current knowledge of ES deficits in urban areas, the overall decrease in ES supply capacity of peri-urban areas is a risk for human well-being in the Mediterranean and poses a serious challenge for the Sustainable Development Goals in the Mediterranean basin
Stochastic `Beads on a String' in the Accretion Tail of Arp 285
We present Spitzer infrared, GALEX UV, and SDSS and SARA optical images of
the peculiar interacting galaxy pair Arp 285 (NGC 2856/4), and compare with a
new numerical model of the interaction. We estimate the ages of clumps of star
formation in these galaxies using population synthesis models, carefully
considering the uncertainties on these ages. This system contains a striking
example of `beads on a string': a series of star formation complexes ~1 kpc
apart. These `beads' are found in a tail-like feature that is perpendicular to
the disk of NGC 2856, which implies that it was formed from material accreted
from the companion NGC 2854. The extreme blueness of the optical/UV colors and
redness of the mid-infrared colors implies very young stellar ages (~4 - 20
Myrs) for these star forming regions. Spectral decomposition of these `beads'
shows excess emission above the modeled stellar continuum in the 3.6 micron and
4.5 micron bands, indicating either contributions from interstellar matter to
these fluxes or a second older stellar population. These clumps have -12.0 <
M(B) < -10.6, thus they are less luminous than most dwarf galaxies. Our model
suggests that bridge material falling into the potential of the companion
overshoots the companion. The gas then piles up at apo-galacticon before
falling back onto the companion, and star formation occurs in the pile-up. A
luminous (M(B) ~ -13.6) extended (FWHM ~ 1.3 kpc) `bright spot' is visible at
the northwestern edge of the NGC 2856 disk, with an intermediate stellar
population (400 - 1500 Myrs). Our model suggests that this feature is part of a
expanding ripple-like `arc' created by an off-center ring-galaxy-like collision
between the two disks.Comment: Accepted by the Astronomical Journal. For color figures and appendix
material, go
tohttp://www.etsu.edu/physics/bsmith/research/sg/arp285/arp285.htm
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