Structures ďentreprise,R&D et incitationsCorporate structure,R&D and incentives

The deregulation of the telecommunications industry and its convergence with the broadcasting and computer industries have led to a variety of alliances within the redefined sector. The paper uses recent developments in the economics of a corporate structure to provide some tools for an analysis of these moves. It focuses on the firm’s choice of internal organization, boundaries and alliances. After a brief recap of mergers and alliances in the three industries, the paper reviews the three possible motivations for such moves : efficiency, acquisition of market power, and objectives of entrenched managers. It then uses a formal model to provide a definition for the usually loose concept of core competency and to determine a firm’s legal boundaries and sphere of influence as a function of its headquarters’ ability to oversee activities. Last, it derives some implications of the analysis for the organization of R&;D.     

Possibility measures and possibility integrals defined on a complete lattice

We consider the definition of possibility measures on complete lattices rather than on complete Boolean algebras of sets. We give a necessary and sufficient condition for the extendability of any mapping to such a possibility measure. We also associate two types of integrals with these possibility measures, and discuss some of their more important properties, amongst which a monotone convergence theorem.     

Every longest circuit of a 3‐connected,K3,3‐minor free graph has a chord

Carsten Thomassen conjectured that every longest circuit in a 3‐connected graph has a chord. We prove the conjecture for graphs having no K_3,3 minor, and consequently for planar graphs. © 2008 Wiley Periodicals, Inc. J Graph Theory 58: 293–298, 2008     

Gerbstoffe

Ohne Zusammenfassung     

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

Direct‐injection mass spectrometry (DIMS) techniques have evolved into powerful methods to analyse volatile organic compounds (VOCs) without the need of chromatographic separation. Combined to chemometrics, they have been used in many domains to solve sample categorization issues based on volatilome determination. In this paper, different DIMS methods that have largely outperformed conventional electronic noses (e‐noses) in classification tasks are briefly reviewed, with an emphasis on food‐related applications. A particular attention is paid to proton transfer reaction mass spectrometry (PTR‐MS), and many results obtained using the powerful PTR‐time of flight‐MS (PTR‐ToF‐MS) instrument are reviewed. Data analysis and feature selection issues are also summarized and discussed. As a case study, a challenging problem of classification of dark chocolates that has been previously assessed by sensory evaluation in four distinct categories is presented. The VOC profiles of a set of 206 chocolate samples classified in the four sensory categories were analysed by PTR‐ToF‐MS. A supervised multivariate data analysis based on partial least squares regression‐discriminant analysis allowed the construction of a classification model that showed excellent prediction capability: 97% of a test set of 62 samples were correctly predicted in the sensory categories. Tentative identification of ions aided characterisation of chocolate classes. Variable selection using dedicated methods pinpointed some volatile compounds important for the discrimination of the chocolates. Among them, the CovSel method was used for the first time on PTR‐MS data resulting in a selection of 10 features that allowed a good prediction to be achieved. Finally, challenges and future needs in the field are discussed.     

Highly sensitive and selective separation of intact parathyroid hormone and variants by sheathless CE‐ESI‐MS/MS

Parathyroid hormone (PTH) is a common clinical marker whose quantification relies on immunoassays, giving variable results as batch, brand, or target epitope changes. Sheathless CE‐ESI‐MS, combining CE resolution power and low‐flow ESI sensitivity, was applied to the analysis of PTH in its native conformation in the presence of related forms. Fused silica and neutral‐coated capillaries were investigated, as well as preconcentration methods such as transient isotachophoresis, field‐amplified sample injection (FASI), and electrokinetic supercharging (EKS). The method for the separation of PTH and its variants was first developed using fused‐silica capillary with UV detection. An acidic BGE was used to separate 1–84 PTH (full length), 7–84 PTH, and 1–34 PTH. Acetonitrile was added to the BGE to reduce peptide adsorption onto the capillary wall and transient isotachophoresis was used as analyte preconcentration method. The method was then transferred to a sheathless CE‐ESI‐MS instrument. When using a fused silica capillary, CE‐MS was limited to μg/mL levels. The use of a neutral coating combined with FASI or EKS allowed a significant increase in sensitivity. Under these conditions, 1–84 PTH, 7–84 PTH, and 1–34 PTH were detected at concentrations in the low ng/mL (FASI) or pg/mL (EKS) range.     

Variational fluid flow measurements from image sequences: synopsis and perspectives

Variational approaches to image motion segmentation has been an active field of study in image processing and computer vision for two decades. We present a short overview over basic estimation schemes and report in more detail recent modifications and applications to fluid flow estimation. Key properties of these approaches are illustrated by numerical examples. We outline promising research directions and point out the potential of variational techniques in combination with correlation-based PIV methods, for improving the consistency of fluid flow estimation and simulation.