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Characterization of the electronic band structure of solid state materials is routinely performed using photoemission spectroscopy. Recent advancements in short-wavelength light sources and electron detectors give rise to multidimensional photoemission spectroscopy, allowing parallel measurements of the electron spectral function simultaneously in energy, two momentum components and additional physical parameters with single-event detection capability. Efficient processing of the photoelectron event streams at a rate of up to tens of megabytes per second will enable rapid band mapping for materials characterization. We describe an open-source workflow that allows user interaction with billion-count single-electron events in photoemission band mapping experiments, compatible with beamlines at 3rd and 4rd generation light sources and table-top laser-based setups. The workflow offers an end-to-end recipe from distributed operations on single-event data to structured formats for downstream scientific tasks and storage to materials science database integration. Both the workflow and processed data can be archived for reuse, providing the infrastructure for documenting the provenance and lineage of photoemission data for future high-throughput experiments.

The laser-driven ultrafast demagnetization effect is one of the long-standing problems in solid-state physics. The time scale is given not only by the transfer of energy, but also by the transport of angular momentum away from the spin system. Through a double-pulse experiment resembling two-dimensional spectroscopy, we separate the different pathways by their nonlinear properties. We find (a) that the loss of magnetization within 400 fs is not affected by the previous excitations (linear process), and (b) we observe a picosecond demagnetization contribution that is strongly affected by the previous excitations. Our experimental approach is useful not only for studying femtosecond spin dynamics, but can also be adapted to other problems in solid-state dynamics.

X-ray photoelectron diffraction is a powerful tool for determining the structure of clean and adsorbate-covered surfaces. Extending the technique into the ultrafast time domain will open the door to studies as diverse as the direct determination of the electron-phonon coupling strength in solids and the mapping of atomic motion in surface chemical reactions. Here we demonstrate time-resolved photoelectron diffraction using ultrashort soft X-ray pulses from the free electron laser FLASH. We collect Se 3d photoelectron diffraction patterns over a wide angular range from optically excited Bi\\(_2\\)Se\\(_3\\) with a time resolution of 140 fs. Combining these with multiple scattering simulations allows us to track the motion of near-surface atoms within the first 3 ps after triggering a coherent vibration of the A\\(_{1g}\\) optical phonons. Using a fluence of 4.2 mJ/cm\\(^2\\) from a 1.55 eV pump laser, we find the resulting coherent vibrational amplitude in the first two interlayer spacings to be on the order of 1 pm.

Characterization of the electronic band structure of solid state materials is routinely performed using photoemission spectroscopy. Recent advancements in short-wavelength light sources and electron detectors give rise to multidimensional photoemission spectroscopy, allowing parallel measurements of the electron spectral function simultaneously in energy, two momentum components and additional physical parameters with single-event detection capability. Efficient processing of the photoelectron event streams at a rate of up to tens of megabytes per second will enable rapid band mapping for materials characterization. We describe an open-source workflow that allows user interaction with billion-count single-electron events in photoemission band mapping experiments, compatible with beamlines at \\(3^{\\text{rd}}\\) and \\(4^{\\text{th}}\\) generation light sources and table-top laser-based setups. The workflow offers an end-to-end recipe from distributed operations on single-event data to structured formats for downstream scientific tasks and storage to materials science database integration. Both the workflow and processed data can be archived for reuse, providing the infrastructure for documenting the provenance and lineage of photoemission data for future high-throughput experiments.

Core level binding energies and absorption edges are at the heart of many experimental techniques concerned with element-specific structure, electronic structure, chemical reactivity, elementary excitations and magnetism. X-ray photoemission spectroscopy (XPS) in particular, can provide information about the electronic and vibrational many-body interactions in a solid as these are reflected in the detailed energy distribution of the photoelectrons. Ultrafast pump-probe techniques add a new dimension to such studies, introducing the ability to probe a transient state of the many-body system. Here we use a free electron laser to investigate the effect of a transiently excited electron gas on the core level spectrum of graphene, showing that it leads to a large broadening of the C 1s peak. Confirming a decade-old prediction, the broadening is found to be caused by an exchange of energy and momentum between the photoemitted core electron and the hot electron system, rather than by vibrational excitations. This interpretation is supported by a line shape analysis that accounts for the presence of the excited electrons. Fitting the spectra to this model directly yields the electronic temperature of the system, in agreement with electronic temperature values obtained from valence band data. Furthermore, making use of time- and momentum-resolved C 1s spectra, we illustrate how the momentum change of the outgoing core electrons leads to a small but detectable change in the time-resolved photoelectron diffraction pattern and to a nearly complete elimination of the core level binding energy variation associated with the narrow \\(\\sigma\\)-band in the C 1s state. The results demonstrate that the XPS line shape can be used as an element-specific and local probe of the excited electron system and that X-ray photoelectron diffraction investigations remain feasible at very high electronic temperatures.

piRNAs are crucial for transposon silencing, germ cell maturation, and fertility in male mice. Here, we report on the genetic landscape of piRNA dysfunction in humans and present 39 infertile men carrying biallelic variants in 14 different piRNA pathway genes, including PIWIL1 , GTSF1 , GPAT2, MAEL, TDRD1 , and DDX4 . In some affected men, the testicular phenotypes differ from those of the respective knockout mice and range from complete germ cell loss to the production of a few morphologically abnormal sperm. A reduced number of pachytene piRNAs was detected in the testicular tissue of variant carriers, demonstrating impaired piRNA biogenesis. Furthermore, LINE1 expression in spermatogonia links impaired piRNA biogenesis to transposon de-silencing and serves to classify variants as functionally relevant. These results establish the disrupted piRNA pathway as a major cause of human spermatogenic failure and provide insights into transposon silencing in human male germ cells. piRNAs are small RNA molecules found primarily in the testes of mice and men. Stallmeyer et al. demonstrate that variants in specific genes can disrupt the formation of piRNAs, impairing spermatogenesis and causing human male infertility.

RésumeLa profession infirmière connait une rapide croissance des effectifs dans tous les pays occidentaux. Avec la multiplication des secteurs extrahospitaliers, l’académisation des formations et l’instauration de hiérarchies propres, cette croissance s’accompagne d’un processus de différenciation horizontal autant que vertical. Dans un tel contexte, il convient de restituer les enjeux qui traversent la profession en tenant compte de l’ensemble de ses secteurs d’activité à l’échelle d’un territoire donné. Une analyse de correspondances multiples et une analyse de classification menées sur un échantillon représentatif d’infirmières de Suisse romande (n = 2 923) permet de dégager un espace infirmier dans lequel sont identifiées quatre fractions : les « dominantes médicales », les « dominées médicales », les « élites infirmières », les « hétérodoxes ». Chacune de ces fractions se caractérise par des représentations et pratiques spécifiques, que ce soit dans le domaine de la pratique des soins, de la production de savoirs ou encore de la relation avec la profession médicale. The professional space of nursing : an analysis based on the case of French-speaking SwitzerlandThe nursing profession is experiencing rapid numerical growth in all Western countries. With the proliferation of non-hospital sectors, the academicisation of training and the establishment of distinct hierarchies, this growth is accompanied by a process of horizontal as well as vertical differentiation. In such a context, it is important to reconsider the issues that run throughout this occupation by taking into account all of its sectors of activity at the scale of a specific geographical area. A combination of multiple correspondence analysis and cluster analysis, carried out on a representative sample of nurses from French-speaking Switzerland (n = 2,923) reveals a nursing space in which four segments can be identified : “medically dominant”, “medically dominated”, “nursing elites” and “heterodox”. Each of these segments is characterized by specific representations and practices, whether in the spaces of the practice of care, production of knowledge or relationship with the medical profession.

The nursing profession is experiencing rapid numerical growth in all Western countries. With the proliferation of non-hospital sectors, the academicisation of training and the establishment of distinct hierarchies, this growth is accompanied by a process of horizontal as well as vertical differentiation. In such a context, it is important to reconsider the issues that run throughout this occupation by taking into account all of its sectors of activity at the scale of a specific geographical area. A combination of multiple correspondence analysis and cluster analysis, carried out on a representative sample of nurses from French-speaking Switzerland (n = 2,923) reveals a nursing space in which four segments can be identified: “medically dominant,” “medically dominated,” “nursing elites” and “heterodox.” Each of these segments is characterized by specific representations and practices, whether in the spaces of the practice of care, production of knowledge or relationship with the medical profession.