Effects of landscape structure on vegetation and some animal groups after agriculture abandonment

This research was carried out on the montane belt of a south-exposed watershed in the Intermediary Alps which have been hit by agriculture abandonment. The aim of the study was to study the relationships between vegetation, landscape mosaic, and two kinds of animals using this space at different scales: roe deer (Capreolus capreolus) and earthworms (lumbricids). Landscape dynamics (post-cultural recolonisation) and landscape structure have been approached by means of the Arc/Info geographical information system (GIS). Several methods used to study on one hand roe deer distribution, and, on the other, earthworm abundance and diversity are developed. Of these, in particular, GIS processing is used to sample earthworms according to vegetation dynamics, and roe deer distribution is related to landscape heterogeneity. Earthworms are more abundant and diversified in the key steps of vegetation dynamics. These lumbricids can be considered as functional indicators of these dynamics. Results also demonstrate that both the vegetation type and the landscape heterogeneity have a direct influence on the use of the space by the roe deer. They show themselves to be structural indicators of the landscape.     

Glyphosate immunosensor. Application for water and soil analysis

A fully automated immunosensor for the herbicide glyphosate has been developed on the basis of the immunocomplex capture assay protocol. The sensor carries out on-line analyte derivatization prior to the assay and uses a selective anti-glyphosate serum, a glyphosate peroxidase enzyme tracer, and fluorescent detection. Under optimal conditions, the detection limit achieved is 0.021 microg/L with an analysis rate of 25 min per assay, autonomy of more than 48 h, and sensor reusability >500 analytical cycles. The immunosensor is able to discriminate structurally related molecules, such as aminomethylphosphonic acid, the main metabolite of glyphosate, and other related herbicides, such as glufosinate and glyphosine. Interferences from naturally occurring species (anions, cations, and humic substances) and their elimination were also studied. The immunosensor has been successfully applied to water and soil sample analysis, with good recoveries at levels lower than 1 microg/L. Results obtained with the immunosensor correlate well with data from a magnetic particle ELISA and LC/LC/MS chromatographic method.     

Photosensitization of the skin and fluorescence spectra (author's transl)

We have carried out spectrofluorometric determinations of numerous substances such as drugs, chemicals and plants in order to find out whether there is a correlation between fluorescence data and photosensitization of the skin. A hypothesis on the mechanism of photosensitization is discussed and the data on the fluorescent properties of some 50 products is given.     

Terminologie et unitesTerminology and unitsTerminologie und einheitenTepминoлoгия и eдиницы измepeния

Terminology and units raise and will always raise problems. We have chosen some examples for which more precise definitions would seem useful.     

Supercritical fluid extraction of alkaloids from Ilex paraguariensis St. Hil.

In this work a study about extracts obtained from Ilex paraguariensis St. Hil. leaves with supercritical CO₂ was carried out. Experiments were performed in a pilot-scale extractor with capacity of 1 L at pressure of 120, 150, 170 and 200 bar for four temperature conditions, 313.15, 323.15, 333.15 and 343.15 K. The experimental data were fitted using a mathematical model characterized by the existence of two distinct periods of extraction. Numerical results for the adjusted parameters correlated very well the supercritical extraction experimental data. The confidence of results obtained from mathematical model and experiments was assured through the chi-square test.     

Out of the picture? How incompatible knowledge and distant visual stimuli may foster idea generation

Visual stimuli such as pictures, sketches or prototypes play a major role in idea generation. Companies today often promote the use of these non‐verbal tools during creativity sessions, at the early stages of design. However, recent studies tend to show that these tools do not systematically enhance idea generation. Our research project therefore aims to better understand the contribution of visual stimuli during creativity sessions, and especially the contribution of distant stimuli which present knowledge that appears to be incompatible with the design topic. This study is based on an exploration led at the automotive company Renault by a team working on new services for charging electric vehicles. During idea generation sessions, a set of pictures was used by a meeting facilitator to inspire the team with new ideas. We show that the effects produced by the different pictures are varied: they do not always promote radical expansion, and when they do, expansion is not always of the same nature. Moreover, represented knowledge appears to have a major influence on idea generation, as the most original ideas came from pictures that not only expanded initial knowledge, but also helped to reorder the team's knowledge base and introduce new design rules.     

Identifying representative users in matrix factorization-based recommender systems: application to solving the content-less new item cold-start problem

Matrix factorization has proven to be one of the most accurate recommendation approaches. However, it faces one major shortcoming: the latent features that result from the factorization are not directly interpretable. Providing interpretation for these features is important not only to help explain the recommendations presented to users, but also to understand the underlying relations between the users and the items. This paper consists of 2 contributions. First, we propose to automatically interpret features as users, referred to as representative users. This interpretation relies on the study of the matrices that result from the factorization and on their link with the original rating matrix. Such an interpretation is not only performed automatically, as it does not require any human expertise, but it also helps to explain the recommendations. The second proposition of this paper is to exploit this interpretation to alleviate the content-less new item cold-start problem. The experiments conducted on several benchmark datasets confirm that the features discovered by a Non-Negative Matrix Factorization can be interpreted as users and that representative users are a reliable source of information that allows to accurately estimate ratings on new items. They are thus a promising way to solve the new item cold-start problem.     

Carbon nanotubes in macrophages: imaging and chemical analysis by X-ray fluorescence microscopy

X-ray fluorescence microscopy (microXRF) is applied for the first time to study macrophages exposed to unpurified and purified single-walled (SW) and multiwalled (MW) carbon nanotubes (CNT). Investigating chemical elemental distributions allows one to (i) image nanotube localization within a cell and (ii) detect chemical modification of the cell after CNT internalization. An excess of calcium is detected for cells exposed to unpurified SWCNT and MWCNT and related toxicological assays are discussed.