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Ultrafast X-ray imaging on individual fragile specimens such as aerosols1 , metastable particles2 , superfluid quantum systems3 and live biospecimens4 provides high-resolution information that is inaccessible with conventional imaging techniques. Coherent X-ray diffractive imaging, however, suffers from intrinsic loss of phase, and therefore structure recovery is often complicated and not always uniquely defined4,5. Here, we introduce the method of in-flight holography, where we use nanoclusters as reference X-ray scatterers to encode relative phase information into diffraction patterns of a virus. The resulting hologram contains an unambiguous three-dimensional map of a virus and two nanoclusters with the highest lateral resolution so far achieved via single shot X-ray holography. Our approach unlocks the benefits of holography for ultrafast X-ray imaging of nanoscale, non-periodic systems and paves the way to direct observation of complex electron dynamics down to the attosecond timescale. Femtosecond X-ray Fourier holography imaging with record-high lateral resolution below 20 nm is demonstrated. Phase information is encoded into the interference of the diffraction patterns of a reference particle with a measurement sample.

AbstractThis article offers a critical analysis of the notions of causality and conditioning of linguistic change as these were developed in the French functionalist school, most notably by Martinet (Norsk tidsskrift for sprogvidenskap 18: 434––440, 1955), and some of his followers (Haudricourt, Juilland, Essai pour une histoire structurale du phonéétisme franççais, Klincksieck, 1949, Hagèège, Haudricourt, La phonologie panchronique, Presses Universitaires de France, 1978).In the first section, we analyse the types of causality discussed in functionalist diachronic studies. We then discuss the teleological aspect associated with functionalist causal explanations. Finally, we analyse the distinction between internal and external factors in linguistic change. These issues are inextricably intertwined in diachronic functionalism, but French functionalists adopt different stands with respect to the nature, role and function of internal and external factors, and with respect to the explanation of ‘‘actuated’’ linguistic change.From our critical analysis it appears that the concept of causality has not been fully elaborated by the functionalists, and that the notions of causality and conditioning remain vague. We argue that this is due to a more basic problem at the level of the theoretical conception of language, viz. the fact that Martinet is caught between three perspectives on ‘‘language’’: (1) the linguistic system as existing independently of speakers; (2) the individual speaker and the idiolect as a supposedly homogeneous object of study; (3) the socially stratified and heterogeneous speech community.

Abstract. This contribution offers a historical survey of the views adopted by Romance scholars in methodological discussions tied up with dialectological work conducted between 1875 and 1925. Following an initial phase in which dialectology was strongly linked to folklore-based work and was mainly devoted to the collection of materials, the study of dialects gained a theoretical status within the historical-comparative model. Dialectology then became institutionalised as an academic discipline which developed in various theoretical directions, with Jules Gilliéron and Louis Gauchat as the two key representatives. Whereas Gilliéron favoured the semantic and psychological study of the history of words - to the neglect of the study of their phonetic evolution -, Gauchat stressed the primacy of phonetics, while paying due attention to sociolinguistic phenomena. The methodological principles on which dialectological work was based had a major impact on other domains within Romance linguistics. Walther von Wartburg, for example, integrated the results of dialectological work in his Romance etymological studies, and Antoine Meillet stressed the heuristic and methodological contribution of linguistic geography to historical and general linguistics.

Abstract. This contribution offers a historical survey of the views adopted by Romance scholars in methodological discussions tied up with dialectological work conducted between 1875 and 1925. Following an initial phase in which dialectology was strongly linked to folklore-based work and was mainly devoted to the collection of materials, the study of dialects gained a theoretical status within the historical-comparative model. Dialectology then became institutionalised as an academic discipline which developed in various theoretical directions, with Jules Gilliéron and Louis Gauchat as the two key representatives. Whereas Gilliéron favoured the semantic and psychological study of the history of words - to the neglect of the study of their phonetic evolution -, Gauchat stressed the primacy of phonetics, while paying due attention to sociolinguistic phenomena. The methodological principles on which dialectological work was based had a major impact on other domains within Romance linguistics. Walther von Wartburg, for example, integrated the results of dialectological work in his Romance etymological studies, and Antoine Meillet stressed the heuristic and methodological contribution of linguistic geography to historical and general linguistics.

Pierre Swiggers: Frege on reference in quotation.A discussion about the correct interpretation of an "enigmatic" statement made by Frege.